Dissertation/Thèse

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2024
Thèses
1
  • VLADIMIR RODRIGUES LEMES GONGORA
  • Analysis of the Contribution of Synchronous Condensers in the Presence of Large Amounts of Renewable Source

  • Leader : PAULO FERNANDO RIBEIRO
  • MEMBRES DE LA BANQUE :
  • ELIANE VALENCA NASCIMENTO DE LORENCI
  • ENIO ROBERTO RIBEIRO
  • FERNANDO NUNES BELCHIOR
  • MAURICIO CAMPOS PASSARO
  • PAULO FERNANDO RIBEIRO
  • Data: 21 févr. 2024


  • Afficher le Résumé
  • The electrical power system faces constant changes, adapting gradually to the demands that shape it. In the last decade, growing concern regarding the energy transition has diversified the energy generation matrix plural. Despite the benefits of this new reality, which include contributing to the decarbonization of the planet, the increasing use of renewable sources, such as wind power and solar, results in a weakening electrical grid. It occurs due to the inherent characteristics of these energy sources, such as low production of reactive energy and inertia, high intermittency, and no contribution to the short-circuit capacity. Considering this fact, the importance of utilizing reactive power compensation technology to attenuate electrical transients can lead to various disturbances, such as blackouts. In this context, synchronous condensers are a reemerging technology and are a more efficient solution because they are capable of increasing grid inertia, to collaborate with the short-circuit capacity of the electrical power system. This dissertation aims to analyze the consequences of integrating a large number of renewable energy sources into the electrical system, in addition to evaluating the effectiveness of three types of reactive compensators: synchronous condenser, static synchronous compensator (STATCOM), and the static VAR compensator (SVC). In addition to the theoretical study of each technology, simulations were conducted using suitable software, adapting an existing electrical power system to this new operational reality. Through the comparative evaluation of the effectiveness of each reactive compensation technique, efforts actively sought to identify solutions contributing to mitigating potential electrical instabilities and, ultimately, to providing support for the development of new knowledge and understanding regarding the diverse and modern energy matrix. This initiative results in an electrical system operating with high performance, reliability, and resilience.

Thèses
1
  • VINICIUS BRAGA FERREIRA DA COSTA
  • HOLISTIC DEVELOPMENT OF INTELLIGENT ELECTRICITY MARKETS USING THE TAROT – OPTIMIZED TARIFF – WITH TECHNICAL, ECONOMIC, REGULATORY, AND ENVIRONMENTAL MODELS

  • Leader : BENEDITO DONIZETI BONATTO
  • MEMBRES DE LA BANQUE :
  • TIAGO ANDRÉ SOARES
  • BERNARDO MARQUES AMARAL
  • ANTONIO CARLOS ZAMBRONI DE SOUZA
  • BENEDITO DONIZETI BONATTO
  • BRUNO HENRIQUES DIAS
  • ELIANE VALENCA NASCIMENTO DE LORENCI
  • RAFAEL SILVA CAPAZ
  • WALMIR FREITAS FILHO
  • Data: 21 févr. 2024


  • Afficher le Résumé
  • The deployment of renewable distributed generation (DG) and energy storage systems (ESSs) has been continuously increasing in several countries due to ongoing technical and economic breakthroughs and the implementation of incentive policies. In Brazil, the deployment of on-grid DG under a compensa-tion scheme began in 2012, when the first specific regulation was published (Normative Resolution - REN 482). REN 482 implemented the net metering policy to boost DG installed capacity, as such a policy is highly beneficial for prosumers. However, DG installed capacity has increased substantially, causing decision-makers to rethink the regulatory framework and seek a more balanced solution through Ordinary Law 14300/2022 (OL). In this context, it is clear that regulatory aspects are in the spotlight in Brazil, given their importance to society and the need for changes. However, there is a lack of robust and holistic regulatory models that can be used to implement efficient regulatory frame-works. Thus, analyses are typically empirical. In this context, this thesis fills an essential research gap by developing cutting-edge regulatory models. First, it adapts the optimized tariff model - TAROT (so-cioeconomic regulated electricity market model) and the Bass Diffusion Model - BDM (forecasting model of technology integration) to the context of DG and ESSs to evaluate the consequences of in-creasing penetration levels in the market. Second, it uses the TAROT, BDM, and Life Cycle Assess-ment - LCA (environmental impact analysis technique) to holistically analyze the impacts of the OL, taking into account socioeconomic and environmental indicators. Third, it combines the TAROT, BDM, and LCA into a multi-objective optimization (MOO) approach to obtain holistic and optimal regulatory frameworks for DG. The optimal solutions are compared to the OL to evaluate whether the law achieved a satisfactory trade-off. Fourth, it extends the proposed model by assuming the co-existence between conventional markets and Community-Based Markets (CBMs), defined as groups of members that share common interests, such as trading electricity from DG. Lastly, it introduces a sce-nario-based bi-level optimization problem to account for the random locational aspect of DG systems. Results demonstrate that the OL is successful in mitigating tariff raises and reducing social inequality. By contrast, there are negative implications to the DG business, market welfare, and the environment, as socioeconomic welfare losses at 2.12 billion R$/year or 0.42 billion US$/year, and emissions at 0.35 Mt CO2-eq/year are estimated in total for the 35 analyzed concession areas. The MOO approach indi-cates that the OL is a dominated or non-optimal solution since it is not located on the Pareto frontiers. Thus, while reductions in the compensation for the electricity injected into the grid are necessary in Brazil, the OL defined the compensation empirically, without the application of well-defined methods, implying a sub-optimal solution. Assuming the Euclidian knee points, the optimal solutions implied benefits of around 24% in terms of electricity tariff affordability, with small losses of roughly 6% in terms of socioeconomic welfare and global warming potential. Additionally, one can conclude that CBMs can be significantly beneficial in mitigating energy poverty in Brazil, as benefits of around 1.4% were estimated assuming the whole regulated market, or 16.5% assuming only the CBMs participants. However, such benefits would only take place if low-income consumers could participate in the CBMs. Lastly, the bi-level problem demonstrates the importance of assuming the uncertainties associated with DG integration.

2023
Thèses
1
  • LUIZ GUSTAVO PIEVE NUNES
  • Study of Ferroresonance Phenomena in Potential Transformers Applied to Wind Farm Substations

  • Leader : ESTACIO TAVARES WANDERLEY NETO
  • MEMBRES DE LA BANQUE :
  • ESTACIO TAVARES WANDERLEY NETO
  • GUSTAVO PAIVA LOPES
  • JOSE FELICIANO ADAMI
  • MAURICIO CAMPOS PASSARO
  • Data: 14 févr. 2023


  • Afficher le Résumé
  • This paper presents an analysis of the ferroresonance problem that occurs in potential transformers in wind farm substations from high frequency transients, which has been increasingly recurrent in the context of the Generation of electricity from renewable energy sources. This work also analyzes the capacitances involving the active part of the transformers, which were obtained from data measured in the field, as well as presenting how such capacitances can prevent these transients from occurring. Furthermore, in this paper, a Frequency response analysis will be presented using a typical model of potential transformer that is installed in a wind farm substation. These potential transformers are connected to voltages that, due to their low load, promote the effect of resonance, since, as is widely known, the worst situation the operation of transformer of inductive potential is When it is in emptiness. In this way, this work will be the starting point of a discussion that based on the displacement of the resonance point from the adjustment of capacitances.

2
  • LEONARDO PEREIRA REZENDE MACIEL
  • Selective Protection Against Earth Faults in the Stator of Multiple Generators Connected in Parallel

  • Leader : PAULO MARCIO DA SILVEIRA
  • MEMBRES DE LA BANQUE :
  • CARLOS ALBERTO VILLEGAS GUERRERO
  • LUIS HENRIQUE LOPES LIMA
  • PAULO MARCIO DA SILVEIRA
  • RONALDO ROSSI
  • Data: 17 févr. 2023


  • Afficher le Résumé
  • Generator stator earth fault protection is one of the main topics evaluated during protection studies. Several methods against this type of fault have been developed over the years, however, none of the traditional methods is able to guarantee the selectivity of the protection system in scenarios that consider the operation of multiple generators in parallel, grounded by high impedance.
    From the literature review, it was identified the proposition of a new method capable of overcoming this problem caused by the parallelism of the machines. However, despite the high potential, this methodology was evaluated only through offline simulations.
    Therefore, this dissertation proposes a test platform through a real-time digital simulation environment in the RTDS (Real-Time Digital Simulator) and evaluates the new selective method of protection against earth faults in an electrical system composed of two synchronous generators connected in parallel.
    This work also contributed to the development of an electrical circuit capable of emulating the generation of different levels of third harmonic voltage, both at the terminals and at the neutral of each machine.
    In this context, nine operating scenarios were modeled from the main system and the simulation of phase-to-ground short circuits along the entire length of the stator winding of the synchronous machine was performed. The simulations contemplated the integration of commercial protection relays through the technique called hardware-in-the-loop in RTDS. In addition, for the correct application of the evaluated methodology, a communication system between the equipment was developed.
    The results obtained allow us to conclude that the scope and effectiveness of the evaluated method is conditioned to the harmonic level present in each of the generators that share the same bus.

3
  • DANIEL CARNEIRO DE ALMEIDA
  • STUDY OF THE ELECTRICAL EFFECTS OF THE UNIFEI PHOTOVOLTAIC MINI PLANT ON THE DISTRIBUTION NETWORK

  • Leader : EDUARDO CRESTANA GUARDIA
  • MEMBRES DE LA BANQUE :
  • ANDERSON RODRIGO DE QUEIROZ
  • EDUARDO CRESTANA GUARDIA
  • ROBERTO AKIRA YAMACHITA
  • Data: 17 févr. 2023


  • Afficher le Résumé
  • Distributed Generation (DG), especially photovoltaic solar energy, has been growing a lot in recent years because it has a leveled cost of implementation lower than fossil sources. Aneel Normative Resolution No. 482/2012, which established the compensation system and defined the connection characteristics for distributed micro and mini-generation systems, boosted the expansion of this segment. The supply of energy obtained by photovoltaic systems can make an important contribution to the Brazilian energy matrix, however, it is important that the electrical effects on neighboring networks are analyzed, such as voltage regulation and the thermal limit of conductors, which define the capacity network hosting. The objective of this work is to evaluate the electrical characteristics of the behavior of the feeder circuit of a substation where the photovoltaic plant of UNIFEI will be connected, with an initial capacity of 609,84 [kWp] and its expansion to 976 [kWp] connected to the supply network in primary voltage of 13.8 kV in the southern region of Minas Gerais on the CEMIG network. The tariff modality contracted by the consumer unit is the green hourly tariff of subgroup A4. The methodology proposed for the study consists of analyzing the power flow using the OpenDSS software in the IJAU11 feeder circuit connected to the local substation. The network's physical and electrical characteristics and load curves are drawn from historical BDGD measurements. The physical characteristics of the plant are configured in the PVSystem software in OpenDSS, where the constructive arrangement of the plant on the university campus is configured, considering the conditions of solar irradiation in its geographic coordinates. The electrical effects of voltage and current caused by this plant's power injection into the network were evaluated according to the limits defined in PRODIST, reaching values below the limit, 1.05 pu higher and 0.93 pu lower.

4
  • ALEX ANTONIO COSTA
  • Power Transformers Health Index Assessment: An Asset Management Support Tool

  • Leader : ARMANDO MARTINS LEITE DA SILVA
  • MEMBRES DE LA BANQUE :
  • FERNANDO APARECIDO DE ASSIS
  • ARMANDO MARTINS LEITE DA SILVA
  • JOAO GUILHERME DE CARVALHO COSTA
  • JOSE MARIA DE CARVALHO FILHO
  • Data: 31 mars 2023


  • Afficher le Résumé
  • The aging of equipment installed in the Electric Power System is a worldwide reality. In Bra-zil, large electrical installations such as power plants, transmission lines and substations were built in the 1960s and 1970s. Therefore, equipment that has not yet been replaced has been in operation for over 50 years. The Brazilian Electricity Regulatory Agency (ANEEL) establish-es the remuneration of companies that operate in the electricity sector through criteria that include, among others, quality performance indicators for the supply of electricity and the amount invested by companies, assuming for the power transformer installed in distribution substations a depreciation rate such that the equipment is considered fully obsolete in 35 years.
    The need to replace aging equipment competes with other demands on electricity distributors, such as the need to expand the system to meet the load growth and to return dividends to in-vestors. In this context, companies in the electricity sector have sought to improve the man-agement of their assets, through norms and methods that allow a detailed analysis of tech-nical, economic and strategic criteria.
    This dissertation presents the health index as a relevant metric in asset management, capable of prioritizing investment needs in the renewal of companies’ power transformer installations. The proposed work details the creation of this index for substation power transformers, de-scribing the necessary data to diagnose the conditions of the internal components (winding, core, oil and solid insulation), high voltage bushings and on-load tap changer (OLTC), as well as it presents all the mathematical equations that allow its calculation.
    The proposal is applied in a Brazilian electricity distribution company, which adopted the health index according to the criteria presented in this dissertation to classify its 681 power transformers, installed in 354 substations. The classification is one of the asset management tools adopted by the company to provide technical and economic justification for the invest-ment plan for the 2023-2027 cycle presented to ANEEL.

5
  • MARCIANO DE LIMA MEDEIROS
  • Efficiency of Coupling Between Photonic Crystal Fibers and Photonic Integrated Circuits

  • Leader : DANILO HENRIQUE SPADOTI
  • MEMBRES DE LA BANQUE :
  • DANILO HENRIQUE SPADOTI
  • FELIPE BELTRAN MEJIA
  • JORGE RICARDO MEJIA SALAZAR
  • MATEUS AUGUSTO FAUSTINO CHAIB JUNQUEIRA
  • Data: 19 avr. 2023


  • Afficher le Résumé
  • Research interest: In this dissertation, the coupling problem between silicon nanoguides and the "outside world," namely an optical fiber, was numerically investigated using the FDTD method. The process of guiding light from the fiber into a nanoguide is referred to as optical coupling, and the coupling problem arises from the dimensional incompatibility between the conventional optical fiber core and the cross-sectional area of the integrated nanoguides. Currently, this is one of the most significant challenges faced by researchers in the field of silicon nanophotonics. Although the manufacturing of silicon photonic devices has achieved high quality due to compatibility with CMOS fabrication processes, the transition at the interface between the fiber and the nanoguide is characterized by considerable insertion losses due to the coupling problem. Thus, solving this problem holds great importance for the application of silicon photonic integrated circuits in optical communications..

    Objectives: The objective of this work is to address the coupling interface problem between optical fibers and silicon nanoguides, using photonic crystal fibers instead of conventional optical fibers. For this purpose, uniform Bragg gratings are employed as a coupling technique, and the coupling efficiency to the photonic crystal fiber is investigated through numerical simulations, considering the coupling angle, lattice parameters, as well as the physical parameters of the fiber, specifically the air hole diameter. Therefore, this study focuses on the examination, modeling, and optimization of the coupling technique using Bragg gratings to achieve efficient coupling between photonic crystal fibers and silicon nanoguides.

    Results obtained: The simulations results show that efficient coupling can be achieved between photonic crystal fibers and SOI waveguides. The coupling efficiency was investigated based on two types of uniform Bragg couplers. The first one is a simple grating coupler etched on the surface of a nanoguide integrated in the SOI platform. The second one is a Bragg grating coupler with a bottom metallic reflector. In the latter, a gold reflector was added to maximize the reflection at the oxide/substrate interface of the SOI platform and reuse the radiated energy to the substrate. Efficiency simulations with the standard coupler demonstrate a maximum coupling efficiency of 32.6 % at a coupling angle of 10°. Meanwhile, a maximum coupling efficiency of 70.3 % is demonstrated when the reflector is added. Furthermore, an interesting dependence of the coupling efficiency on the air hole diameter of the photonic crystal fibers has also been determined, indicating that this parameter should be appropriately chosen to optimize the coupling efficiency.

6
  • MAURO KEN ITI UEMORI
  • EFFICIENCY ORIENTED HYDROGENERATOR DESIGNHYDROGENERATOR DESIGN

  • Leader : EDSON DA COSTA BORTONI
  • MEMBRES DE LA BANQUE :
  • BERNARDO PINHEIRO DE ALVARENGA
  • EDSON DA COSTA BORTONI
  • JORGE JOHNNY ROCHA ECHEVERRIA
  • RICARDO ELIAS CAETANO
  • ROBERTO AKIRA YAMACHITA
  • Data: 5 juin 2023


  • Afficher le Résumé
  • A detailed description of a salient pole synchronous vertical hydrogenerator will be presented, discussing the design, the manufacturing processes and the materials of all the main components.
    A description of all the losses involved in the calculation of the efficiency is elaborated, their origins and methods for the reduction of the losses and consequent increase of the efficiency.
    To consolidate the concepts, a theoretical approach is discussed on the principles of electrical and thermal dimensioning of synchronous generators.
    To enrich the theoretical approach, two application cases were presented. In each case, two alternatives were simulated, one aiming at high efficiency and the other aiming at reducing the cost.
    The first case deals with a hypothetical generator of 300 MVA and 120 rpm, to expose the optimization procedure. In this case, these sizing rudiments are applied to a generator of 100 MVA and 257.14 rpm that represents a real generator, manufactured, designed and successfully commissioned.
    In the second case, in addition to simulating the machine as it was built, two additional variants are exposed. In a first variant, based on the design of the machine built, a version with the same high efficiency is elaborated, however, introducing technological updates with which the original cost could be reduced. In the second variant, in place of the original project, a generator totally oriented to cost reduction is elaborated. Thus, when comparing results, compare the performance-optimized variant with the fully cost-oriented variant.
    Finally, an analysis is made of the increase in sales prices of high-efficiency oriented generators, when compared to generators sized for cost optimization, and an analysis of gains in the sale of additional energy resulting from the reduction of losses, finally estimating the years of operation required to match the price increase.

7
  • GUILHERME BERTUOL RODRIGUES DE QUEIROZ
  • Fault Location in Extra-High Voltage Transmission Lines: Theory and Application of Phasor-Based Algorithms

  • Leader : PAULO MARCIO DA SILVEIRA
  • MEMBRES DE LA BANQUE :
  • FREDERICO OLIVEIRA PASSOS
  • JOSE MARIA DE CARVALHO FILHO
  • KLEBER MELO E SILVA
  • PAULO MARCIO DA SILVEIRA
  • Data: 5 juil. 2023


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  • Fault location algorithms present different formulations, data requirements, and parameters that make them applicable or not to a specific scenario. Understanding these requirements and the characteristic errors in different scenarios is essential to enable the selection of the most appropriate approach. This work presents several fault location algorithms based on phasors from one and two terminals and analyzes their performance in cases of actual faults and simulated faults in Extra High Voltage Transmission Lines.

    The presented algorithms were implemented in a software in the MATLAB environment for analysis of faults simulated by ATPDraw and for the analysis of actual faults using files generated by Protection Relays and Digital Fault Recorders. The algorithm performance results were compiled into graphs for analysis. The performances were evaluated for different faults types and different sources of error.

    The one-end fault-location algorithms used in this study have features to reduce the error caused by fault resistance combined with load current and system non-homogeneity. The two-end fault-location algorithms solve this problem and have features to reduce error due to synchronization failure. However, algorithms that use the symmetrical components approach can present considerable errors in the case of non-transposed transmission lines or lines with long non-transposed sections. For these cases, matrix-based approaches were used.

    The theoretical presentation of the algorithms and the results of the simulations make it possible to indicate the most viable solution based on parameter requirements, available input data, and the effects of different error sources present in each case, improving fault location estimates. Tables presenting the effects of the error sources and input data requirements have been developed to support this choice. A more accurate fault location estimate reduces the time and cost for transmission line inspection, reducing system restoration time, contributing to the safety of people, the environment, and the transmission system, as well as reducing potential financial penalties for equipment unavailability or compensations fines.

8
  • BRAEN GLEISER ARAUJO
  • EVALUATION OF CONVENTIONAL AND RNA-BASED EXCITATION LOSS PROTECTION OF SYNCHRONOUS GENERATORS IN THE PRESENCE OF SVC

  • Leader : AURELIO LUIZ MAGALHAES COELHO
  • MEMBRES DE LA BANQUE :
  • ADRIANO BATISTA DE ALMEIDA
  • AURELIO LUIZ MAGALHAES COELHO
  • IVAN PAULO DE FARIA
  • WANER WODSON APARECIDO GONCALVES SILVA
  • Data: 7 juil. 2023


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  • As the electrical power system (SEP) expands, it becomes necessary to take precautions regarding stability and power transmission issues, as they become increasingly complex. In this scenario, the use of Flexible Alternating Current Transmission System (FACTS) devices improves the stability and power flow optimization of the network. However, the integration of FACTS into transmission lines (TLs) can modify the voltage and current amplitude and angle values of the system where they are inserted, thus altering the network has characteristics and consequently, the trajectory of the measured impedance. Such effects can then be reflected in the operation times and coverage ranges of relay protection zones that relays on impedance measurement, such as the loss of excitation protection for synchronous machines connected to these TLs. In this context, this study presents computational simulations and laboratory tests to analyze the response of protection systems for synchronous machines connected to TLs with Static Var Compensators (SVC) FACTS devices. Various events with and without the presence of SVCs are simulated and stored in a database for offline closed loop testing with a generator protection relay, evaluating the response time of traditional loss of excitation protection characteristics. These characteristics are compared with a method based on a Multilayer Perceptron Artificial Neural Network (ANN) implemented to enhance the protection response in these scenarios.

9
  • MARCELO GRANATO SIQUEIRA
  • Development of Fast Charger for Electric Vehicles

  • Leader : ROBSON BAUWELZ GONZATTI
  • MEMBRES DE LA BANQUE :
  • ROBSON BAUWELZ GONZATTI
  • WILSON CÉSAR SANT`ANA
  • RONDINELI RODRIGUES PEREIRA
  • SÍLVIA COSTA FERREIRA
  • Data: 14 juil. 2023


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  • The increase in the combustion of fossil fuels to meet the growing demand for energy is one of the main causes for the increase in the concentration of carbon dioxide (CO2) in the atmosphere. In an attempt to slow this growing environmental pollution, the vast majority of the world’s nations have committed to reduce emissions of CO2 and other greenhouse gases. With this in mind, the transition from combustion vehicles to electric vehicles (EVs) is seen by many authors as one of the most promising developments for reducing greenhouse gas emissions and improving air quality. However, the biggest obstacle to the popularization of this type of vehicle is the time needed to recharge its batteries, during a trip for example. Having said all these paradigms, this dissertation presents the development of a three-phase fast charger for electric vehicle batteries. Nominally this charger is designed to deliver up to 50 [kW] and 100 [A] nominal to the battery. The first charging stage consists of an AC/DC converter coupled to an LCL filter and connected to the power grid at 220 [V] Phase-Phase. The second stage consists of a DC/DC interleaved converter, which is connected to the DC bus at 500 [V]. The charger is coupled to the battery in order to validate charging through the CC-CV method (Constant Current - Constant Voltage). The operation of the converter and its control technique are validated through simulations in the Matlab software, using the Simulink tool. Then, the charger is built using the AC/DC first stage and its operation is demonstrated using a bank of batteries. The control strategy is implemented in the DSP TMS320F28379D from Texas Instruments, using the software Code Composer. Satisfactory results were obtained in the battery charging control although the practical implementation is done on a small scale, the control system can be easily used at higher powers, just with adjustments in the control gains. The importance of compensating the dead-times that appear in the practical part is highlighted.

10
  • ACÁSSIO MARCELO DIAS PINTO
  • Photovoltaic generation: analysis of influencing factors according to the Design of Experiments (DoE)

  • Leader : EDUARDO CRESTANA GUARDIA
  • MEMBRES DE LA BANQUE :
  • EDUARDO CRESTANA GUARDIA
  • MARCIO ANDREY ROSELLI
  • ROBERTO AKIRA YAMACHITA
  • Data: 24 juil. 2023


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  • Photovoltaic solar energy has shown strong growth in recent years because it is a clean, renewable, competitive and accessible energy. In this context, the Design of Experiments (DoE) is premised on the analysis, modeling and optimization of experiments, with statistical reliability, data and cost savings. In this way, photovoltaic generation was analyzed according to meteorological variables: solar radiation, temperature, wind speed and relative humidity, as well as the isolated and combined influence of each factor, with the objective of validating the model in uncontrollable conditions and define the optimal operating point. Pareto charts and Response Surfaces support the generated power equations, allowing the prediction of results and future estimates, as well as the definition of technical and economic optimal points. In addition, the case study demonstrated the validity of the DoE in an open environment and in the operation of the panels, allowing the identification of noise throughout the analyses, such as wind speed and relative humidity. Situations still little explored in the literature, even with high efficiency in noise analysis and with the potential to contribute to the diagnosis of failures and preliminary studies for the implementation of new projects.

11
  • WILLIAM HENRIQUE PEREIRA COSTA
  • Multiclass Classification of Electroencephalogram Signals for Motor Imagery Tasks Using Statistical Signal Processing and Deep Learning

  • Leader : LUIZ EDUARDO BORGES DA SILVA
  • MEMBRES DE LA BANQUE :
  • GISCARD FRANCIMEIRE CINTRA VELOSO
  • JOAO ONOFRE PEREIRA PINTO
  • LUIZ EDUARDO BORGES DA SILVA
  • Data: 27 juil. 2023


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  • Research Interests: Efficient classification of electroencephalogram (EEG) signals is crucial for the development of brain-computer interface systems. However, the complexity and variability of EEG signals pose significant challenges for accurate classification. Additionally, this study has social relevance as it can contribute to the development of assistive brain-computer interfaces, benefiting individuals with severe motor impairments, such as those who have experienced a stroke. These interfaces have the potential to improve the quality of life for these individuals by enabling communication and device control through brain activity.
    Objectives: This study aimed to compare the performance and computational cost of an artificial neural network using different signal processing techniques for the classification of resting state and left/right wrist movement imagination states from EEG signals. Three statistical signal processing techniques, Principal Component Analysis (PCA), Independent Component Analysis (ICA), and Singular Spectrum Analysis (SSA), were explored in conjunction with a Convolutional Neural Network (CNN) to enhance the classification of EEG signals.
    Results Obtained: The results revealed that the PCA technique led to a reduction in training time of up to 63.5% without significantly compromising performance in terms of classification accuracy. PCA proved to be a promising approach, capturing relevant information from the EEG signals and improving the CNN's ability to classify accurately. On the other hand, both ICA and SSA techniques did not yield promising results. ICA had negative effects on feature extraction, resulting in decreased classification accuracy by the CNN. SSA, on the other hand, showed consistently low performance across all evaluated metrics, indicating challenges in capturing discriminative information from the EEG-IM signals.

12
  • HUMBERTO JOSÉ GONZAGA
  • Remote Monitoring and Diagnostics Applied to Industrial Processes, Within the Industry 4.0 Concept

  • Leader : TALES CLEBER PIMENTA
  • MEMBRES DE LA BANQUE :
  • ALEXANDRE BARATELLA LUGLI
  • GABRIEL ANTONIO FANELLI DE SOUZA
  • ROBSON LUIZ MORENO
  • TALES CLEBER PIMENTA
  • Data: 3 août 2023


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  • In light of the industry 4.0, remote monitoring and diagnosis applied to industrial processes is critical. In industrial plants where technologies are lagging, this process can be performed using protocols and tools such as MQTT, Modbus and Node-RED. This essay addresses concepts of industry 4.0 applied on remote monitoring and diagnosis, with the aim of create an interface that allows the communication with all field devices which operate with Modbus RTU protocols and the user, remotely. The proposed work aims to create an interface that allows the remote access to field devices in industrial plants already installed and without the available technology. In the context of Industry 4.0, remote monitoring and diagnostics applied to these processes are critical to continuous improvement, decision making, cost reduction, optimization of maintenance, quality improvement and other factors related to efficiency and safety of the production process. To solve the problems related to the lack of technology focused on Industry 4.0, studies were carried out to develop an interface capable of making the connection between outdated field devices, which operate on protocols such as Modbus RTU, and remote access. It was made a study of the main protocol used on the shop floor, which do not have direct access to technologies for remote communication. From these data were researched technologies and devices capable of communicating with this protocol, perform the exchange of data and enable their access remotely. Thus was studied a tool capable of communicating with this interface, based on the TCP/IP standard, to make access and remote control from a computer, from anywhere, connected to the internet network. Thus, a solution was developed that performs the exchange of data between a field device and an online platform through the MQTT protocol, which operates on the TCP/IP architecture. The results show the possibility of adequacy of existing processes for the concept of Industry 4.0. This system allows monitoring the efficiency and performance of operations, which allows it to reduce the response time to unexpected events and failures in the process. This study contributes to the advancement of knowledge in applications related to the adequacy of industrial plants within the concept of Industry 4.0, providing a practical and validated solution for the execution of the mentioned activities, which allows its use in future research in implementations related to updating industrial processes.

13
  • EDUARDO DELMONDES GRAVA
  • A Proposal for a Transmission Line Protection Relay Using Artificial Neural Networks

  • Leader : PAULO MARCIO DA SILVEIRA
  • MEMBRES DE LA BANQUE :
  • AURELIO LUIZ MAGALHAES COELHO
  • CARLOS ALBERTO VILLEGAS GUERRERO
  • DENIS VINICIUS COURY
  • FREDERICO OLIVEIRA PASSOS
  • PAULO MARCIO DA SILVEIRA
  • Data: 21 août 2023


  • Afficher le Résumé
  • This work proposes the application of artificial neural networks (ANNs) as a working principle of a transmission line protection relay. The proposed relay has the functions of fault classification and location, distance protection and neutral overcurrent. Each application is performed by an ANN multilayer perceptron (MLP). The methodology used in the training of protection functions allows the performance of well-defined characteristics such as quadrilateral and mho. The architecture of the networks was defined aiming at optimization and performance speed, making use of the smallest possible number of neurons. The training process of the ANNs was carried out through the Solver tool, from Microsoft Excel, with the help of several applications developed in the Visual Basic language. One of the programs developed in VBA is used in the evaluation of neural networks in the face of real disturbances of the electrical system using oscillography files. The five designed neural networks were implemented in hardware through an ESP32 microcontroller. All program code steps are detailed. The final part of the work analyzes the results of the prototype relay tests carried out in a real-time simulator RTDS. The practical tests performed prove that the proposed relay is fast and safe, confirming the feasibility of the proposal for the protection of transmission lines.

14
  • GIUSEPPE SCABELLO SILVA
  • A Fuzzy inference-based TCSC control technique to improve dynamic power system responses

  • Leader : GABRIEL ANTONIO FANELLI DE SOUZA
  • MEMBRES DE LA BANQUE :
  • EVALDO RENÓ FARIA CINTRA
  • GABRIEL ANTONIO FANELLI DE SOUZA
  • ROBSON LUIZ MORENO
  • Data: 22 août 2023


  • Afficher le Résumé
  • The expansion of the transmission network has been taking place significantly in recent years. Aiming to maximize the load flow, stability, power quality in transmission lines, and in the entire power system, FACTS devices begin to be employed. These devices work to maintain the nominal electrical parameters in addition to help the system to recover its steady state after a disturbance or even a collapse. Thyristor Controlled Series Compensator (TCSC) is a type of FACTS devices and is able to change the line impedance improving power flow as well as contributing to system stability. Many studies have been carried out, and researches have been published, to define the best TCSC control techniques, some of which are already in use. Due to the great diversity of control techniques, finding the most appropriate method to be used in a given system is a non-trivial task. The present dissertation will bring two published techniques to control TCSC based on the lead-lag model, whose parameters are defined through metaheuristic techniques such as Genetic Algorithm and Particle Swarm. The results found in these publications will be simulated in a Matlab/Simulink environment and confronted with the Fuzzy logic application written with linguistic inference, simplified rules and simple membership functions. Three scenarios, with different faults, will be proposed and the simulations result and variables will be compared as angular velocity, angular displacement, electrical power and network equivalent impedance. The two published models and the proposed fuzzy logic will achieve stability with very similar results in all simulations. The big advantage in the use of Fuzzy logic is in its modeling simplicity, unlike the heuristic techniques that require much more modeling time and sometimes long iterations to achieve acceptable parameters.

15
  • ALLANN BRENO DE SALES PEREIRA
  • INSERTION LOSS AND RETURN LOSS TESTS IN MECHANICAL FIBER OPTIC CONNECTIONS

  • Leader : ROBSON LUIZ MORENO
  • MEMBRES DE LA BANQUE :
  • ENIO ROBERTO RIBEIRO
  • LEONARDO MESQUITA
  • ROBERTO SHIGUERU NOBUYASU JUNIOR
  • ROBSON LUIZ MORENO
  • Data: 22 sept. 2023


  • Afficher le Résumé
  • This work presents an understanding about the execution of tests on fiber optic
    connectorizations used in data transmission. In this study, optical loss measurements
    is made in mechanical connectors such as Insertion Loss (IL) and Return Loss (RL)
    based. The test methodology was based on the certification requirements for the
    commercialization of telecommunications products by the National
    Telecommunications Agency (ANATEL) and international standards of the
    International Electrotechnical Commission (IEC).
    In addition to the fundamental theoretical argument, we performed an
    evaluation of field-mounted connectors from ten different manufacturers sold in Brazil.
    The tests were carried out at the light source wavelength of 1550 nm based on two
    groups of tests: climatic and mechanical tests. In which the optical loss values are
    measured both initially and during the tests, thus depending on the requirements of the
    standards. Furthermore, It was carried out through the facilities and equipments from
    the Laboratory for Testing Telecommunications Equipment (LTET) at the Federal
    University of Itajubá (UNIFEI).

16
  • GABRIEL VINICIOS SILVA MAGANHA
  • Simulation of PLC in Web Browsers: A Tool for Enhancing Electrical Engineering Education

  • Leader : ANTONIO CARLOS ZAMBRONI DE SOUZA
  • MEMBRES DE LA BANQUE :
  • ADRIANO BATISTA DE ALMEIDA
  • ANTONIO CARLOS ZAMBRONI DE SOUZA
  • CLAUDIA ELIANE DA MATTA
  • PEDRO PAULO BALESTRASSI
  • Data: 29 nov. 2023


  • Afficher le Résumé
  • This master’s thesis explores the development and impact of a web-based Programmable
    Logic Controller (PLC) simulator, aiming to improve technical and professional education
    and promote digital inclusion. In a context where industrial automation is rapidly expanding,
    and PLCs play a crucial role in controlling industrial machines and processes, the
    complexity of PLC programming represents a substantial obstacle, especially for beginners.
    The developed PLC simulator, by offering a safe and controlled virtual environment
    for programming and simulation, emerges as an innovative educational solution, allowing
    users to experiment and test various programming and control strategies. Its main advantage
    lies in its web-based access, enabling use anywhere with internet access, which
    provides flexibility to students and professionals and eliminates the need for physical
    equipment, reducing the risk of damage or interruptions in production. The relevance of
    simulators in the teaching and learning process, also recognized in academic literature,
    is particularly highlighted in this study, given their ability to provide a safe environment
    for the practice of complex skills, crucial in risky fields such as electrical engineering and
    industrial automation. The dissertation approach includes everything from the conception
    to the technical implementation of the simulator, in addition to an analysis based on
    research with technical level users, aiming to evaluate its effectiveness in the learning process.
    The results obtained are important for the continuous improvement of the tool and
    for the expansion of its educational applications, emphasizing the simulator’s potential to
    improve the teaching of PLC programming and contribute significantly to the training of
    more qualified professionals prepared to meet the demands of the automation industry.

17
  • GUILHERME DA SILVA SANTOS
  • Proposal for Implementing Mitigation Measures to Reduce Short-Circuit Levels in Circuit Breaker Overstressed Study

  • Leader : AURELIO LUIZ MAGALHAES COELHO
  • MEMBRES DE LA BANQUE :
  • ADRIANO BATISTA DE ALMEIDA
  • AURELIO LUIZ MAGALHAES COELHO
  • IVAN PAULO DE FARIA
  • WANER WODSON APARECIDO GONCALVES SILVA
  • Data: 15 déc. 2023


  • Afficher le Résumé
  • The constant growth in electrical power demand requires careful planning to expand
    the generation power plants and the transmission lines while maintaining the efficiency,
    safety, and reliability of the electrical system. The integration of new projects introduces
    operational challenges to the electrical grid, such as increased power flows and short-circuit
    currents. In some instances, these currents may exceed the rated capacity of circuit
    breakers, resulting in their being overstressed. Therefore, it is imperative to assess the
    equipment’s rated withstand capability against the fault currents in the circuit where it is
    installed. The Brazilian Electric System (SEB) currently confronts significant challenges,
    particularly concerning high levels of short-circuit currents. This is especially notable in
    the electrical area of Rio de Janeiro, which contains numerous substations where circuit
    breakers have been overstressed. This situation has constrained the expansion of the
    system. In this context, this study entailed comprehensive simulations of the Rio de
    Janeiro area to determine short-circuit currents within the simulation network. To conduct
    these simulations, we utilized the computational program Simultaneous Fault Analysis
    (ANAFAS) and conducted an extensive investigation of circuit breakers being overstressed
    under actual electrical system conditions. To address the issue of circuit breakers being
    overstressed due to high fault currents, we also present the principal mitigating measures
    commonly employed in Brazil and worldwide. The primary objective of this study was to
    research structural solutions for implementation in the Rio de Janeiro area, thus replacing
    the temporary operational measures that have been previously utilized. Additionally, the
    study estimated the necessary investments for implementing these definitive solutions.
    The significance of this work extends to the practical application of the proposed measures
    within the substations of the Rio area, considering the current analysis timeframe and the
    future configuration of this electrical system.

18
  • MURILO LEANDRO FRANCO
  • Computational modeling and simulation of a Back-to-Back Voltage Source Converter (VSC) in an industrial smart microgrid.

  • Leader : BENEDITO DONIZETI BONATTO
  • MEMBRES DE LA BANQUE :
  • BENEDITO DONIZETI BONATTO
  • GUSTAVO PAIVA LOPES
  • JOSE CARLOS DE MELO VIEIRA JUNIOR
  • MAURICIO CAMPOS PASSARO
  • ROBSON BAUWELZ GONZATTI
  • Data: 15 déc. 2023


  • Afficher le Résumé
  • This work presents a case study on the application of a voltage source converter in
    an industrial microgrid, using multilevel topology in a Back-to-Back arrangement. The
    main purpose is to understand whether the application of a B2B-VSC converter can be
    feasible in an industrial microgrid, replacing pyrotechnic short-circuit limiters, indicating
    the advantages and disadvantages in a technical analysis. The microgrid, characterized by
    the presence of synchronous generators, substantial loads, and large transformers, faces
    significant challenges related to the high level of short-circuit. In this context, engineering
    criteria are presented to assess the thermal and dynamic sustainability of medium-voltage
    panels and circuit breakers, whose replacement represents not only a considerable economic cost but also impacts on the availability of the production process. The main proposal includes the development of a detailed mathematical model for the multilevel Back-to-Back converter, its implementation in the ATPDraw program, and the simplified modeling of a pyrotechnic short-circuit limiter. The results indicate that, although the pyrotechnic limiter operates satisfactorily, the search for alternatives is justified due to cost and replacement time implications. The Back-to-Back converter emerges as an innovative solution, and the case study reveals promising results in terms of short-circuit limitation.

19
  • FÁBIO SILVA BORGES
  • Design of a microstrip antenna with dual operating band and polarization for 5G/Wi-Fi applications

  • Leader : DANILO HENRIQUE SPADOTI
  • MEMBRES DE LA BANQUE :
  • DANILO HENRIQUE SPADOTI
  • RAFAEL ABRANTES PENCHEL
  • RAMON MAIA BORGES
  • RENAN ALVES DOS SANTOS
  • Data: 18 déc. 2023


  • Afficher le Résumé
  • This masters dissertation presents the design of a rectangular microstrip antenna with dual feeding, operating band and polarization. It operates at a frequency of 3.5 GHz with linear polarization, in the plane of the electric field (in fundamental mode (TMz100) – applied to 5G technology) and at a frequency of 5.2 GHz with linear polarization, in the plane of the field magnetic (in third order mode (TMz030) – applied to Wi-Fi technology). The antenna is formed from the orthogonal geometric superposition of two techniques, one that allows increased gain and other that allows the filtering of high-order modes. Based on the simulation and measured results, the antenna operated in two bands, 5G and Wi-Fi, with minimum isolation between ports of −16 dB. Ultimately, the functioning of each of the intermediate geometries was separately validated and, finally, the functioning of the final model.

Thèses
1
  • THIAGO ARANTES NOGUEIRA
  • Short Duration Current Impulse Waveform Effects on the Degradation and Energy Absorption Capability of Zinc Oxide Varistors

  • Leader : ESTACIO TAVARES WANDERLEY NETO
  • MEMBRES DE LA BANQUE :
  • AELLFCLÊNITON MOURONER MACIEL DINIZ
  • CREDSON DE SALLES
  • ESTACIO TAVARES WANDERLEY NETO
  • GEORGE ROSSANY SOARES LIRA
  • IVAN PAULO DE FARIA
  • Data: 31 mars 2023


  • Afficher le Résumé
  • Installed surge arresters are subjected to different types of overvoltages, and the varistors, which are their active element, must be able to not only absorb the energy from these overvoltages, but also present degradation levels that do not compromise its functionality after the event. The lack of correlations between the energy absorbed by a varistor and its degradation motivated the investigation proposed in this research, in which varistors from different manufacturers had their energy absorption capabilities evaluated by current impulses at different waveforms with durations in the order of microseconds. The degradation level of the samples during the ageing process was evaluated through the measurement of the leakage current between impulse applications, in which the power, the resistive peaks and the harmonic distortion were analyzed. The results present a direct relation between the impulse duration and the number of discharges with the same energy withstood in different waveforms, and indicate that the time under and overvoltage is more critical to varistor ageing than the peak value of the discharged current. However, samples submitted to shorter impulses presented more intense variations on their leakage current, which can lead to a thermal runaway of the varistor in operating conditions.

2
  • BRUNO EDUARDO CARMELITO
  • Hosting Capacity of Electric Vehicles on LV/MV Distribution Grids—A New Methodology Assessment

  • Leader : JOSE MARIA DE CARVALHO FILHO
  • MEMBRES DE LA BANQUE :
  • FERNANDO NUNES BELCHIOR
  • JOSE MARIA DE CARVALHO FILHO
  • PAULO HENRIQUE OLIVEIRA REZENDE
  • PAULO MARCIO DA SILVEIRA
  • THIAGO CLE DE OLIVEIRA
  • Data: 26 avr. 2023


  • Afficher le Résumé
  • The subject of electric mobility has aroused great interest among researchers
    in recent years, being a actual topic under discussion as Electric Vehicles (EV) reach
    greater market share. Electric mobility, which is linked to the energy transition,
    experiences a transformation of concepts that starts with the consumption of fossil
    fuels and ends with zero carbon emissions. These changes correspond to the need
    for cleaner, decentralized, digitized energy delivery systems and services, as well
    as greater electrification of modes of transportation. In this context, this thesis
    proposes and implements a novel methodology for calculating the hosting capacity
    of EVs in low and medium voltage distribution systems through a case study.
    The carrying capacity of EVs is evaluated in the literature using load flow
    processing, which uses several criteria and methods for evaluation. On the one hand,
    deterministic methods produce a single number for EV hosting capability and ignore
    the uncertainties inherent in the allocation process. Stochastic methods, on the other
    hand, generate a probability distribution of hosting capabilities. The suggestion of
    a new methodology that combines deterministic and stochastic methods, takes into
    account several operational criteria, and can be used in low and medium voltage
    applications becomes more suitable and innovative.
    The results indicate that the distribution system’s EV hosting capacity
    varies with sector of the evaluated network. Loading can increase and alter the
    load curve considerably in the secondary distribution system’s downstream of the
    transformer, causing undervoltage and overload in the grid. The charging rate of
    transformers with EV input, on the other hand, can change the primary distribution
    system’s hosting capacity.

3
  • CAIO MEIRA AMARAL DA LUZ
  • SWITCHED-CAPACITOR-BASED HYBRID RESONANT BIDIRECTIONAL BUCK-BOOST CONVERTER FOR DIFFERENTIAL POWER PROCESSING IN PHOTOVOLTAIC SYSTEMS

  • Leader : ENIO ROBERTO RIBEIRO
  • MEMBRES DE LA BANQUE :
  • DENIZAR CRUZ MARTINS
  • ENIO ROBERTO RIBEIRO
  • FABRICIO BRADASCHIA
  • FERNANDO LESSA TOFOLI
  • ROBSON LUIZ MORENO
  • WANER WODSON APARECIDO GONCALVES SILVA
  • Data: 10 août 2023


  • Afficher le Résumé
  • In most practical applications, photovoltaic (PV) modules should be connected in
    series to reach a desired voltage level for a specific application. An important problem
    that frequently affects this type of connection is mismatch among the modules. It can be
    caused by several factors that can be classified into permanent or temporary. To mitigate
    this problem, bypass diodes are the most widely used technique owing to its simple
    implementation. However, this technique is only appropriate for temporary mismatch. In
    permanent mismatch, more sophisticated mitigation techniques are required. In this
    context, the concept of differential power processing (DPP) has emerged as a prominent
    solution for permanent mismatch owing to its low cost, simple implementation, and high
    performance. For this purpose, DC-DC converters, named DPP converter, are connected
    between the adjacent PV modules. The way these DPP converters are connected along
    the PV series originates four main architectures: PV-PV, PV-Bus, hybrid, and ladder. In
    this way, the aim of this study is to develop and implement a novel topology named BBBReSC. It consists of a hybrid architecture that incorporates elements from both BBB and
    SC converters. Notably, it tackles key challenges that impact the PV-to-PV and PV-tovi
    Bus architectures. Specifically, it addresses issues like the diverted current accumulation
    in the PV-to-PV architecture and high voltage stresses associated with the PV-to-Bus
    architecture. Another important issue is that the hard-switching operation of
    semiconductors in SC converters may lead to high switching losses and poor efficiency.
    In turn, the introduced solution referred to as ReSC converter provides operation under
    soft-switching conditions while mitigating such undesirable losses. To demonstrate the
    effectiveness of the BBB-ReSC topology, tests using PV strings composed of four, six, and,
    eight FV modules were conducted. These tests were performed through simulations in
    MATLAB/Simulink® environment, as well as with the use of an experimental prototype.
    The experimental results have shown an improvement in harvested energy of up to 50%
    for the PV string consisting of four modules and 33% for the PV string with six modules.

4
  • VINÍCIUS VELOSO ELEUTÉRIO NOGUEIRA
  • Integration of Computer Vision and Photogrammetry for Automatic Piston Ring Measurement

  • Leader : TALES CLEBER PIMENTA
  • MEMBRES DE LA BANQUE :
  • LESTER DE ABREU FARIA
  • ALEXANDRE BARATELLA LUGLI
  • GABRIEL ANTONIO FANELLI DE SOUZA
  • LUIS HENRIQUE DE CARVALHO FERREIRA
  • TALES CLEBER PIMENTA
  • Data: 1 nov. 2023


  • Afficher le Résumé
  • The piston ring is a critical component in internal combustion engines whichs plays a vital role by sealing the gap between pistons and cylinder walls. This sealing is indispensable to prevent gas leakage from the combustion chamber and to adequately control lubricant distribution. With the evolution of engines, operating with increasingly compression ratios and lower lubricant viscosities to maximize performance and effiency, precision in piston ring manufacturing has become imperative. Thus, the manufacturing of these elements entails designing rings that meet the complexities of the combustion system, manufactured with rigorous dimensional accuracy. In this manufacturing process, ensuring that the rings conform to the project's error margins is essential to avoid rejections during quality analysis and subsequent rework. This necessitates, in conjunction with process qualification, a reliable measurement system to optimize production and guarantee high-quality products.
    In this context, this study examines the presently employed manual measurement method and proposes a distinct automated approach aimed at enhancing measurement consistency and reducing waste. The central proposition is the development of an alternative measurement method based on image processing. This approach offers several advantages, including optimized automation, process agility, and the absence of direct contact with the measured components. The research explores the design of a machine vision system that measures piston rings through images, ensuring the required precision. The study integrates established computer vision techniques with novel contributions, including modifications in subpixel edge detection, estimation of contour angles using zero phase filters, and adjustments in the system's execution flow. Additionally, the method employs photogrammetry techniques to map image points to the real world, correcting image distortions, inclinations, and relative distances between measurement points and the camera, as well as accounting for part height, throught the implementation of a proposed height compensation method. The developed prototype is validated through tracking tests using standard blocks and comparisons with conventional equipment. The results attest to the prototype's ability to maintain tracking across various size, height, position, and inclination variations. Remarkably, the proposed automated method stands out compared to manual measurements, particularly in assessing ring opening. Ultimately, the implementation of this innovative method has the potential to substantially optimize the piston ring manufacturing process, enhancing consistency and agility to meet the essential quality requirements for these vital components in internal combustion engines.

5
  • FERNANDA MITCHELLY VILAS BÔAS ABREU
  • Condition Monitoring of Motor Generator Units in Thermoelectric Power Plants using Nelson's Rules

  • Leader : LUIZ EDUARDO BORGES DA SILVA
  • MEMBRES DE LA BANQUE :
  • CLAUDIO INACIO DE ALMEIDA COSTA
  • HELCIO FRANCISCO VILLA NOVA
  • LUIZ EDUARDO BORGES DA SILVA
  • MATEUS MENDES CAMPOS
  • RONDINELI RODRIGUES PEREIRA
  • YOHAN ALI DIAZ MENDEZ
  • Data: 8 nov. 2023


  • Afficher le Résumé
  • The physical structure of Thermoelectric Power Plants is made up of several components, among which the internal combustion engines (MCI) stand out. Fundamentally, in this type of engine, as the name suggests, energy is produced by burning the fuel inside. As this generation of thermoelectric energy remains constant during the plant's operating period, these engines are constantly subject to stress, due to different factors such as number of starts, average load, load variation and ambient temperature. However, most of the time, these existing monitoring systems only indicate whether the monitored parameters are non-compliant after a failure has occurred – not allowing an early analysis of the machine's operating conditions. Knowing this, in this work, a methodology for early analysis of failures in the internal combustion engine, based on the Statistical Control Process and Nelson's Rules, is proposed in an unprecedented way to analyze, in a predictive manner, the operating conditions of the machine based on in historical data from the UTE supervisory system. In order to give a practical appeal to the analyzes carried out in this work, the operational data used are the real records of the year 2019, of the internal combustion engine model 18V46 (from the manufacturer Wärtsilä), which constitute the thermoelectric plant in question. The analysis mechanism is validated through two case studies, the first being a comparison between the degree of severity of the operational condition of generating unit 5 and the shutdown event of this same generating unit on 08/01/19 and the second case study statistical notes on the degree of severity of generating unit 5, when it returns from post-shutdown maintenance. It is demonstrated that the results obtained with the proposed methodology adequately corresponded to the entries in the shift record, namely the degradation of certain subsystems of the motor generating unit 5 until its stop in August 2019 - which makes it a promising tool both for making early decisions about plant maintenance and for helping machine operators check whether machines that have returned from maintenance are in good condition.

6
  • EDEN DE OLIVEIRA PINTO COELHO
  • Comparison of Financial Assessment and Risk Management Metrics for Analysis of Investments in Distributed Photovoltaic Microgeneration

  • Leader : BENEDITO DONIZETI BONATTO
  • MEMBRES DE LA BANQUE :
  • BENEDITO DONIZETI BONATTO
  • EDSON DE OLIVEIRA PAMPLONA
  • FERNANDO NUNES BELCHIOR
  • GIANCARLO AQUILA
  • RAFAEL DE CARVALHO MIRANDA
  • RICARDO TORQUATO BORGES
  • Data: 14 nov. 2023


  • Afficher le Résumé
  • Electrical energy plays an important role in people's lives, being the main source of energy used to carry out daily needs. As consequence, the use of clean technologies to generate electrical energy has become the first choice for consumers, initially due to the support of public policies, and over time because they are simply the most economical. In the case of photovoltaic electricity generation, the behavior of solar radiation and the power of the generation system have uncertainties that may be relevant for classifying risk in investments for this type of energy generation. Therefore, this research proposes to investigate, in accordance with Law 14,300, the risk of investing in residential distributed generation systems. For this, cost and investment analysis will first be carried out using deterministic LCOE and NPV metrics for residential consumers who produce their own energy in 26 municipalities located in the state of Minas Gerais. Next, a risk classification will be made, based on the stochastic NPV approach, calculated through Monte Carlo Simulation. Through this approach, the CVaR risk metric will be compared with the Omega index, highlighting the importance of using such measures for this type of risk analysis. The results showed that there are differences in the ranking between the deterministic and stochastic approaches between the municipalities analyzed, and the municipalities in which a higher tariff on electricity is charged were the places where the greatest potential and the greatest risk on financial return occurred, in addition to presenting a greater probability of gain in relation to the probability of losses when investing in residential photovoltaic systems compared to the other municipalities analyzed.

7
  • LÍGIA CINTRA PEREIRA
  • Analysis of the Impact of Penetration of Distributed Energy Resources Through Economic Modeling of the Smart Electricity Market

  • Leader : BENEDITO DONIZETI BONATTO
  • MEMBRES DE LA BANQUE :
  • BENEDITO DONIZETI BONATTO
  • EDSON DE OLIVEIRA PAMPLONA
  • FERNANDO NUNES BELCHIOR
  • GIANCARLO AQUILA
  • MADSON CORTES DE ALMEIDA
  • RAFAEL DE CARVALHO MIRANDA
  • Data: 21 nov. 2023


  • Afficher le Résumé
  • The electricity market, with the insertion of distributed energy resources into the system, moves towards becoming an intelligent market in the future. In this energy transition context, technical, economic, and regulatory aspects must be reviewed, as well as new agents and business models must emerge. Balancing the conflicting interests of all agents involved is an increasingly complex task, and policy makers must seek an environment of healthy growth and maturation of the sector, in a sustainable manner, to reduce energy poverty and add greater value to society. Decision-making presupposes the existence of models that allow the future impacts of the measures under analysis to be considered and evaluated. Thus, this thesis pro-poses to use the socioeconomic model of the electricity market called Optimized Tariff (TAROT), with the main objective of adding to it the representation of new agents and possibilities of transactions in this intelligent market to allow the analysis of socioeconomic welfare generated with the inclusion of these resources in the network. The modeling of costs associated with distributed energy generation in distribution company finances, in addition to new agents, such as the aggregator, are the distinguishing features of this work. Based on the new proposed equations, an innovative scenario for the provision of ancillary services by prosumers to the utility network was evaluated. The application of the model was carried out using data from a Brazilian distribution company, and it was possible to verify, in addition to the effects on the main agents in the sector, the penetration levels of distributed energy resources that add value to society. Through the proposed model, it is possible to simulate different scenarios and their impacts on agents, thus proving to be an important tool to assist in decision-making by regulatory agents.

8
  • DENILSON FERREIRA
  • Elaboration of Energy Balance: A Model for the Brazilian States

  • Leader : LUIZ EDUARDO BORGES DA SILVA
  • MEMBRES DE LA BANQUE :
  • JAMIL HADDAD
  • JOAO ONOFRE PEREIRA PINTO
  • LUIZ EDUARDO BORGES DA SILVA
  • ROBERTO AKIRA YAMACHITA
  • RONDINELI RODRIGUES PEREIRA
  • Data: 24 nov. 2023


  • Afficher le Résumé
  • This work considers the importance of energy in various aspects of people's lives, including comfort, job creation, wealth production, technological and scientific development, and innovation. It is associated with the challenge of constantly increasing energy supply and the urgency of sustainability throughout the processes from production to consumption. In this context, the importance of the State in the sector is highlighted, as it acts through regulatory agencies and even controlled companies positioned in different segments, aiming to achieve a difficult and complex dynamic balance across various aspects within each segment. At this point, the discussed theme focuses on the role of the State in providing information about the sector, enabling various agents and stakeholders to position themselves appropriately, considering different approaches, including the State's own role in developing public policy. In this regard, by discussing concepts and the relevance of energy statistics, specifically energy balances as the main source of information and essential data for the energy market's development, this study sought to better understand the reasons and difficulties faced by Brazilian subnational governments in publishing their respective Energy Balance Sheets (BEEs) annually. Additionally, it proposed a model based on best practices referenced in the literature to facilitate this process. To achieve this, the study aimed to understand historical and objective reasons related to the diminishing role of federal units in the sector by examining recent history, sectoral restructuring processes, the verification and understanding of institutional spaces for energy management within the organizational structure of these governments, and the mapping and analysis of their respective energy policies and planning. This analysis aimed to establish a connection between these aspects and the production of state energy balances. Based on an extensive literature review on energy balance sheet preparation, a model was proposed. A case study related to its application in the State of Mato Grosso do Sul was presented, which resulted in the development of a system that automates part of the preparation process based on the proposed model.

9
  • WANDER MENDES MARTINS
  • STUDY OF ARTIFICIAL INTELLIGENCE AND COMPUTER VISION METHODS FOR TRACKING TRANSMISSION LINES WITH THE AID OF UAVs

  • Leader : TALES CLEBER PIMENTA
  • MEMBRES DE LA BANQUE :
  • ALEXANDRE CARLOS BRANDAO RAMOS
  • ELCIO HIDEITI SHIGUEMORI
  • GABRIEL ANTONIO FANELLI DE SOUZA
  • HILDEBRANDO FERREIRA DE CASTRO FILHO
  • ROBSON LUIZ MORENO
  • TALES CLEBER PIMENTA
  • Data: 11 déc. 2023


  • Afficher le Résumé
  • Currently, Unmanned Aerial Vehicles (UAVs) have been used in the most diverse applications in both the civil and military sectors. In the civil sector, aerial inspection services have been gaining a lot of attention, especially in the case of inspections of high voltage electrical systems transmission lines. This type of inspection involves a helicopter carrying three or more people (technicians, pilot, etc.) flying over the transmission line along its entire length which is a dangerous service especially due to the proximity of the transmission line and possible environmental conditions (wind gusts, for example). In this context, the use of UAVs has shown considerable interest due to their low cost and safety for transmission line inspection technicians. This work presents research results related to the application of UAVs for transmission lines inspection, autonomously, allowing the identification of invasions of the transmission line area as well as possible defects in components (cables, insulators, connection, etc.) through the use of Convolutional Neural Networks (CNN) for fault detection and identification. This thesis proposes the development of an autonomous system to track power transmission lines using UAVs efficiently and with low implementation and operation costs, based exclusively on rea-time image processing that identifies the structure of the towers and transmission lines durin the flight and controls the aircraft´s movements, guiding it along the closest possible path.

10
  • LÊNIO OLIVEIRA PRADO JÚNIOR
  • Downtime Prediction for Sediment Decantation and Cleaning of Protection Grids of Generating Units in Hydroelectric Power Plants Using Hidden Markov Models and Bayesian Networks

  • Leader : GUILHERME SOUSA BASTOS
  • MEMBRES DE LA BANQUE :
  • ADLER DINIZ DE SOUZA
  • AGNELO MAROTTA CASSULA
  • ANDRE LUIS MARQUES MARCATO
  • GUILHERME SOUSA BASTOS
  • MAURICIO CAMPOS PASSARO
  • Data: 14 déc. 2023


  • Afficher le Résumé
  • Hydropower plants installed in the Amazon basin are negatively influenced by transporting logs and sediments from the river bed. All transported material accumulates in the protection grids, which are installed in the water intake of the generating units to prevent the entry of this material and avoid damage to the turbines, which would result in economic losses. The accumulation of material on the protection grids reduces the water drop and, consequently, the flow available for generation, which results in load losses, preventing the generation unit from operating at full capacity. The presented problem occurs at the Jirau hydropower plant, located on the Madeira River and has 50 generation units, each with the potential to generate 75MW at total capacity. This plant operates on a run-of-river basis, meaning there is no reservoir for water storage. Therefore, all water resources must be used when available. The fact that it operates on a run-of-river, together with the problem of transporting logs and sediments, brings challenges to the operation of the plant, as the sediments that accumulate in the protection grids and consequently reduce the generation potential require the complete shutdown of the generating units so that the accumulated dirt can decant, thus enabling the resumption of the waterfall, and consequently the flow available for generation. A large number of generation units and the different location dispositions of equipment in the river alter the sediment accumulation profile, making it difficult to define rules that define the necessary stoppage time for each unit to decant the dirt and restart generation at total capacity. In this scenario, instead of relying only on the experience of operators, developing efficient methods capable of determining the ideal stoppage time for each generation unit becomes essential. In this work, prediction models using Bayesian Networks and Hidden Markov Models are proposed to estimate the downtime required for decanting the dirt from each generation unit so that it can be used again for generation in the shortest possible time. Big Data and Analytics techniques are also used to collect and process the large volume of data existing at the hydroelectric plant. The results demonstrate that the developed models could satisfactorily infer the time required for sediment decantation. The resulting model makes it possible to query information using various information, including the obstruction level when a unit stops, the obstruction level at restart time, whether neighboring units are operating, and in which power range.

11
  • BRUNO RENÓ GAMA
  • Non-Invasive Online System for Prediction of Insulation Damage in Electric Motors

  • Leader : WILSON CÉSAR SANT`ANA
  • MEMBRES DE LA BANQUE :
  • CARLOS EDUARDO TEIXEIRA
  • ERIK LEANDRO BONALDI
  • LUIZ EDUARDO BORGES DA SILVA
  • ROBSON BAUWELZ GONZATTI
  • RONDINELI RODRIGUES PEREIRA
  • WILSON CÉSAR SANT`ANA
  • Data: 15 déc. 2023


  • Afficher le Résumé
  • The importance of electric motors in industry is undeniable. Many of these machines play
    a critical role in the processes in which they are integrated. Thus, an unplanned outage of
    one of these devices can disrupt the operation of the entire system, leading to operational
    risks and consequent financial losses. Among the causes of faults in three-phase induction
    motors, we observe that between 26% and 36% are caused by insulation failures.
    The literature suggests the Frequency Response Analysis (FRA) technique as a method
    capable of gradually monitoring insulation aging, offering early diagnosis compared to traditional monitoring techniques. However, current methodologies for online analysis - with
    the machine in operation - besides being invasive, present some limitations, such as: lack
    of repeatability in measurements, influence of parallel loads to the monitored asset, and
    reduced spectrum analysis area. In this context, this work proposes an analysis methodology to address current challenges highlighted in the literature. The study also proposes a sweep frequency system through inductive coupling, ensuring a non-invasive analysis system, a condition that simplifies its field installation and consequent market adoption. The proposed system uses the Absolute Sum of Logarithmic Error (ASLE) statistical indicator to monitor motor’s insulation condition. A laboratory aging test of a low-voltage motor was carried out and the proposed system was used to monitor it, noting the ASLE index evolution from 0.31 to 1.28, indicating the progression of dielectric degradation. In contrast, the monitoring performed with a megometer showed no variations in the insulation resistance parameter, indicating values between 300 GW and 400 GW. An aging test of a medium-voltage motor was also conducted at the Laboratório de Alta Tensão (LAT)
    of the Universidade Federal de Itajubá (UNIFEI). In this test, the proposed equipment
    pointed out variations in the ASLE indicator from 0.09 to 0.17 in the first week, reaching
    0.21 at the end of the first month, and 1.03 by the end of the test. The test was monitored
    with various market equipment, among them, the partial discharge measurement system,
    which indicated variations in the discharge rate only after 24 days of testing.

2022
Thèses
1
  • MARCELO SANTANA DE ALMEIDA
  • Proposal for the implementation of a communication circuit for ultra-dense networks of active electrodes for EEG equipment.

  • Leader : TALES CLEBER PIMENTA
  • MEMBRES DE LA BANQUE :
  • ALEXANDRE BARATELLA LUGLI
  • GABRIEL ANTONIO FANELLI DE SOUZA
  • TALES CLEBER PIMENTA
  • Data: 24 févr. 2022


  • Afficher le Résumé
  • Although traditional electroencephalogram equipment is used on a large scale in the clinical environment, it is common for them to present problems such as electromagnetic interference readings from their electrodes, low-resolution capability in their exams, due to the small number of electrodes to obtain information, and their low mobility, due to the large number cables for your communication.

    Thus, through this work, a solution was proposed that focuses on the development of a concentrator circuit and a secondary circuit, which are responsible for exchanging information from the ultra-dense network of active electrodes (512 or more), as well as sending this information to an external source - microcomputers, routers, and wireless equipment - where this information will be stored and processed and a communication protocol, which will use a single wire to carry out such information exchange.

    The blocks of the concentrator and the secondary circuits were implemented using the descriptive language Verilog ®, through smaller blocks, being constituted by a serializer circuit and a parallelizing circuit, allowing the exchange of data through the bus, a tri-state circuit, enabling the control of the transmission of information and a circuit responsible for the coordinated operation of the previous circuits in the realization of external requests.

    The implemented circuits were tested and validated through FPGAs, demonstrating the ability to perform external requests, with the exchange of information using a single communication wire. Where a digital oscilloscope was used to monitor and prove this communication.

2
  • JOHNNY JOSÉ OROZCO NIVELO
  • Analysis of Study Methodologies for Starting Large Motors in Isolated Electrical Systems

  • Leader : JOSE MARIA DE CARVALHO FILHO
  • MEMBRES DE LA BANQUE :
  • FERNANDO NUNES BELCHIOR
  • FREDERICO OLIVEIRA PASSOS
  • JOSE MARIA DE CARVALHO FILHO
  • MARCEL FERNANDO DA COSTA PARENTONI
  • Data: 3 mars 2022


  • Afficher le Résumé
  • This dissertation presents a comparative analysis between the two main methodologies used to carry out the studies of motor starting, the first called the static method (snapshot), in the frequency domain, and the second, called the dynamic method (The Speed- Torque and acceleration-Time), in the time domain, using as a case study a typical offshore platform composed of generators and large induction motors. For this, the software Power Tools for Windows (PTW) and the real-time digital simulator (RTDS) were used to perform the analysis of the two methodologies. From the results of the case study, the main advantages and disadvantages of each one are pointed out, as well as the differences in the requirements associated with the parameters of the electrical system equipment necessary to apply each methodology. The simulation results showed that the study of motor starting in the time domain provides more complete information than the static one, even more for this type of system in particular. This work reveals the need for the selection criteria between the two methodologies to be defined in the IEEE 3002.7-2018 standard and for isolated systems it is highly recommended to perform a time domain analysis.

3
  • ANTONIO GABRIEL MARQUES MULLER
  • Rehabilitation and renovation of substations: aspects related to equipment, reliability and physical arrangement

  • Leader : JOSE MARIA DE CARVALHO FILHO
  • MEMBRES DE LA BANQUE :
  • AIRTON VIOLIN
  • JOAO GUILHERME DE CARVALHO COSTA
  • JOSE MARIA DE CARVALHO FILHO
  • RONALDO ROSSI
  • Data: 4 mars 2022


  • Afficher le Résumé
  • Aging and obsolescence are factors that occur throughout the Brazilian electrical system, which is why the modernization of substations is inevitable. It is important to highlight that the electrical systems in Europe and in Japan have gone through this process in recent years, and it is inevitably already taking place in the National Interconnected System – NIS. Substations must also be renewed when the network parameters (short circuit current, rated current, voltage, etc.) change. This is due to changes in the transmission network, or when you want to improve the substation's reliability.
    The adoption of new project assumptions, specially in the electricity sector, faces several barriers in the market, whether due to lack of knowledge of the technology, to public notice requirement or to project standardization. During the circuit breaker technology upgrade process, for example, the design engineers probably encountered the same difficulties.
    When faced with the need to upgrade the substation or the need to replace equipment, an engineer with little experience will probably specify equipment equal to the existing one, without making a more accurate analysis of the subject, considering a long-term horizon and new technologies.
    This work aims to propose a methodology for assessing the need and/or the convenience of carrying out the refurbishment of transmission substations (known by the terms: uprating and upgrading), through a case study, highlighting the main points that should be observed by all professionals involved in the project, supporting the expansion and planning of such systems with relevant decisions.

4
  • LUCAS BARROS SCIANNI MORAIS
  • Short-Term Load Forecasting Using Artificial Neural Networks

  • Leader : JOSE WANDERLEY MARANGON LIMA
  • MEMBRES DE LA BANQUE :
  • ANDERSON RODRIGO DE QUEIROZ
  • EDUARDO CRESTANA GUARDIA
  • GIANCARLO AQUILA
  • JOSE WANDERLEY MARANGON LIMA
  • Data: 4 mars 2022


  • Afficher le Résumé
  • In electrical power systems, one of the main challenges faced by independent system operators (ISO) is ensuring a reliable balance between energy supply and demand. For this, a proper planning of the system operation is necessary. Short-Term Load Forecasting (PCCP) is essential in this process, as it assists in planning daily operations, including matching demand and supply, setting future electricity prices and defining generation reserves. As smart grid technologies and intermittent renewable energy sources have increased significantly in electricity markets, the task of forecasting the load has increased in complexity and poses a challenge for ISOs. Nonlinear models based on machine learning techniques have become quite popular in recent years, as has the use of hybrid models focused on specific problems. This work focuses on the development of artificial neural network models to solve the PCCP problem, among them the MultiLayer Perceptron (MLP) networks with different numbers of layers and the Long-Short Term Memory (LSTM) and Gated Recurrent Unit (GRU) recurrent networks in its unidirectional and bidirectional versions. In addition to the data provided by ISO, predicted temperature information obtained from the Global Ensemble Forecast System (GEFS) model was used to try to generate more accurate load forecasts. In general terms, the results show that the recurrent models produce greater accuracy and more reliable results than the other models, including the models used by the Brazilian ISO. This is emphasized with the application of the Diebold-Mariano in a paired comparison test between models.

5
  • BERNALIZE DO ROSÁRIO VILA NOVA
  • TARIFF REGULATION: APPLICATION OF THE TAROT ECONOMIC MODEL TO OPTIMIZE THE ELECTRIC ENERGY TARIFF PRACTICED IN THE ELECTRICAL SECTOR OF SÃO TOMÉ AND PRÍNCIPE

  • Leader : JOSE WANDERLEY MARANGON LIMA
  • MEMBRES DE LA BANQUE :
  • BENEDITO DONIZETI BONATTO
  • EDUARDO CRESTANA GUARDIA
  • JOSE WANDERLEY MARANGON LIMA
  • LUANA MEDEIROS MARANGON LIMA
  • Data: 11 mars 2022


  • Afficher le Résumé
  • In a monopolistic electricity market, regulation of the electricity sector is essential to avoid overinvestment that does not match the quality of service provided. In this sense, this work aims to evaluate the structure of the electricity sector and the tariff system of São Tomé and Príncipe (STP), and to propose a more efficient methodology of tariff calculation through the economic market model, TAROT (Optimized Tariff), for the determination of a tariff that is capable of promoting the economic and financial balance of the Water and Electricity Company (WEC), and to ensure that the levels of quality of service and the demand for electricity are met, while considering the ability to pay according to the income of consumers. In addition, the impact of the tariff increases on low-income families and WEC was analyzed. It is necessary to create tariff policies that enable the inclusion of these families in the WEC electrical system. In this sense, the tariff should be increased gradually, and it is essential that in addition to it I reflected the operational costs of the company, also ensures that the low-income population has access to electricity at more affordable prices. Finally, an analysis of investment in energy sources was carried out as viable alternatives to complement the current electricity generation system (diesel thermoelectric) in São Tomé and Príncipe. For this, we used the indicators of economic viability analysis: Net Present Value (NPV), Internal Rate of Return (IRR), Minimum Attractiveness Rate (MAR) and discounted Payback. It was found that the insertion of alternative energy sources in the energy matrix together with Energy Efficiency, in addition to contributing to improve efficiency and safety in generation, would also significantly reduce the operational costs that the company has with the import of diesel to generate electricity, in addition to promoting increased competition in the electric market.

6
  • WÉLINGTON BORSATO RODRIGUES
  • Analysis of 5G usage in Smart Grids Applications

  • Leader : BENEDITO DONIZETI BONATTO
  • MEMBRES DE LA BANQUE :
  • ALEXANDRE BARATELLA LUGLI
  • BENEDITO DONIZETI BONATTO
  • DANILO HENRIQUE SPADOTI
  • MADSON CORTES DE ALMEIDA
  • Data: 23 juin 2022


  • Afficher le Résumé
  • The Brazilian electrical system has particular characteristics that demand very specific operational requirements and Smart Grids applications. One example is the fact of the system is mostly interconnected, with a large territorial extension and with most of the electric generation being of hydraulic origin, what is a situation that allows the inclusion of water resource monitoring as an Smart Grids application. In addition, other applications are present, such as remote metering, energy management, automation, demand response, vehicular electrification, distributed generation and con-trol of protection systems. One factor that makes these applications viable is the use of communication technologies, which must meet specific requirements for each kind of application. Therefore, a wide range of technologies need to be analyzed carefully and technically for each case, such as WiMAX, NB-IoT, LoRa, Sigfox, Bluetooth, Zigbee, GOES, Wi-Fi, Ingenu, 6LoWPAN, DASH7 and cellular technologies. In this scenario, the telecommunications system in Brazil is constantly being updated and is being prepared to receive the 5G cellular network, which has been analyzed in all the aforementioned applications and is shown to be viable in most of them. In addition, 5G has been widely studied, being one of the most cited wireless communication technologies in scientific publications related to Smart Grids. This scenario shows a great interest of the scientific community of 5G in Smart Grids context.

7
  • LUÍS FELIPE BENATTI
  • Integrated Subtransmission Reliability Assessment - Lines and Substations

  • Leader : JOSE MARIA DE CARVALHO FILHO
  • MEMBRES DE LA BANQUE :
  • AIRTON VIOLIN
  • JOAO GUILHERME DE CARVALHO COSTA
  • JOSE MARIA DE CARVALHO FILHO
  • LUCAS RAMALHO DE LIMA
  • Data: 30 juin 2022


  • Afficher le Résumé
  • The purpose of this dissertation is the presentation and application of a method for estimating reliability indicators for energy subtransmission systems, also known as high voltage distribution systems. The methodology must associate the topology of the distribution lines with the substation arrangements, thus being able to determine the reflection of this set on the continuity indicators of the final consumers. The motivation for this study will be given by the peculiarity of the subtransmission system, as they are few redundant, with many cases whose system is radial. This portion of the electrical system is the beginning, in fact, of energy distribution to most customers and has strong interaction with the distribution networks and substations. As are the points of supply of the distribution systems, they have a direct impact on the indicators of continuity of their customers and, consequently, of their own concession.

    This work proposes the use of some statistical and physical tools that simulate the operation of energy distribution systems and, consequently, estimate their performance through their regulated indicators. Graph models are presented in 4 operational circumstances: Normal operation; post-maintenance; post-defect and post-maneuver. The methodology proposes the use of linear programming to identify the transition between these states, being the great differential presented in this work, as it allows an intelligent algorithm, associated with the component models presented here, to determine which equipment must be effectively maneuvered to isolate the defect, directing the solution to the lowest possible load shedding.

8
  • YAGO ARAÚJO DOS SANTOS
  • Development of a Digital Twin for Fish Transposition System with Virtual Reality Support in Hydro Power Plants

  • Leader : LUIZ EDUARDO BORGES DA SILVA
  • MEMBRES DE LA BANQUE :
  • ERIK LEANDRO BONALDI
  • HELCIO FRANCISCO VILLA NOVA
  • LUIZ EDUARDO BORGES DA SILVA
  • RONDINELI RODRIGUES PEREIRA
  • Data: 20 juil. 2022


  • Afficher le Résumé
  • One of the problems commonly faced by Hydro Power Plants (HHP) is related to the
    inefficiency of their fish transposition system (FTS). Often, the implemented system is
    not functioning properly, due to lack of control, monitoring, operational capacity, orderly
    maintenance procedures and data transparency. If the FTS does not work correctly, the
    fish, instead of opting for the alternative path offered by the system, end up following
    water flows that do not result in migration. In this context, the environmental inspection
    bodies hold the enterprise responsible for the damage caused to the environment and
    the community, through the application of fines. Some pass through the pipelines of the
    generating machines, others remain parked on the dam threshold or close to the spillway.
    Thus, they are held hostage by the operations carried out at the plant, which can promote
    the mass death of fish. Having presented the problem, the objective of this work is to create a digital twin (DT) supported by virtual reality for a FTS, aiming at the general
    optimization of the structure. In this way, it will be possible to control the real structure
    through a computational model that faithfully represents the physical system. The implemented DT consists of four main tools: 2D supervisory, 3D supervisory, maintenance
    management system and a mobile application. Each tool has a specific function and was
    created to make up the needs of operation, monitoring and maintenance. In addition, the
    set assists in the construction of operating histories, which contribute to the transparency
    and presentation of data.

9
  • DANIEL DE ALMEIDA ARANTES
  • System for Simultaneous Determination of Flow Rate and Water Content in Fuel Oils

  • Leader : LUIZ EDUARDO BORGES DA SILVA
  • MEMBRES DE LA BANQUE :
  • CARLOS EDUARDO TEIXEIRA
  • GISCARD FRANCIMEIRE CINTRA VELOSO
  • LEVY ELI DE LACERDA DE OLIVEIRA
  • LUIZ EDUARDO BORGES DA SILVA
  • RONDINELI RODRIGUES PEREIRA
  • Data: 22 juil. 2022


  • Afficher le Résumé
  • The use of fuel oils for energy generation in thermoelectric plants makes an important contribution to the Brazilian power grid, especially during periods of lower water abundance. The fuel oil used by some power plants is a by-product of petroleum refining, and may contain contaminants that are harmful to the machinery when present in considerable amounts. In this context, the present work brings the development of a system for online monitoring of the processes of supplying thermoelectric power plants with heavy fuel oil. This system allows the visualization of the flow rate and the amount of water contained in oil, since this is one of the main contaminants that can be found in this type of fuel. Its application aims to provide the plant with more detailed knowledge about the purchased fuel, as well as allowing the interruption of supply operations in the event of an irregular product. For the implementation of the system, a multi-path ultrasonic method for flow measurement is used, as well as a capacitive method for identifying the water content. This work presents the development of electronic circuits for performing the proposed measurements, including an innovative circuit for measuring capacitance through an oscillating current source. The individual elements of the system are tested and calibrated, ultimately leading to the assembly and installation of a working prototype in a thermoelectric power plant.

10
  • MARCELLA BARBOSA BRANDÃO DA SILVA CAMPBELL
  • Energy dispatch using DESSEM and coupling with operational reality

  • Leader : JOSE WANDERLEY MARANGON LIMA
  • MEMBRES DE LA BANQUE :
  • ANDERSON RODRIGO DE QUEIROZ
  • BENEDITO CLAUDIO DA SILVA
  • JOSE WANDERLEY MARANGON LIMA
  • Data: 22 juil. 2022


  • Afficher le Résumé
  • In January 2020, the National Power System Operator started using the DESSEM program. It is a model developed by CEPEL and aims to determine the daily energy dispatch for the operation of hydrothermal systems, including intermittent sources, with discretization of up to half an hour. This model works in coordination with the DECOMP and NEWAVE models, which are medium and long-term models for determining the dispatch and the hourly energy price for the following day. This work presents a brief history of the Brazilian electricity sector, the way in which the country's electro-energy operation is managed and the old and current model of daily energy dispatch are explained, in addition to the methodology of operation of the post-DESSEM and its repercussions. The objective is to understand and evaluate the interactions between the agents and the ONS with the use of DESSEM as a very short-term model and the deviations observed between the model generation proposals and those that are finalized in the programming stage. The work focuses on the most important plants of the Furnas system, used as a case study. In addition, in order to highlight the difference between the operating policies adopted by the model and those by the ONS, a quantitative analysis was proposed in this work, with the purpose of identifying a possible seasonal variation in order to gain greater sensitivity on the results of the energy operation.

11
  • AMANDA PEREIRA CHIARADIA
  • PRIMARY CONTROL OF MICROGRIDS IN ISLANDING OPERATING CONDITIONS WITH INSERTION OF ELECTRIC VEHICLES

  • Leader : ANTONIO CARLOS ZAMBRONI DE SOUZA
  • MEMBRES DE LA BANQUE :
  • ANTONIO CARLOS ZAMBRONI DE SOUZA
  • BRUNO de NADAI NASCIMENTO
  • CLAUDIA ELIANE DA MATTA
  • MAURICIO CAMPOS PASSARO
  • Data: 22 août 2022


  • Afficher le Résumé
  • With each passing year the electrical system has evolved substantially. This is due to the increase in the inclusion of renewable sources in the network, which includes the concept of smart grids. Microgrids can operate isolated or connected to the main network and are a great alternative to ensure quality and reliability in the supply of electricity.
    In this dissertation, special attention is given to microgrids with islanding problems regarding demand variation, and the concept of electric vehicles connected to the grid. Electric vehicles are used as energy storage to supply energy within the stipulated limits and analyze whether there is a need for their use at the time of islanding. Also, in cases of a non-tolerable operating point, the primary control of frequency and voltage is used to correct the operation of the system.
    The results presented here are based on the IEEE 37-Nodes Test Feeder system, which to make it equivalent to a microgrid, some modifications were made. In this system, it is possible to change the network charge curves, including electric vehicles, number of EVs to be charged and their respective batteries.
    With this, it is expected that the tools used here will be able to analyze and manage the system when there are islanding situations.

12
  • NATÁLIA VILAS BÔAS PAPPI MACIEL
  • Modelling and Simulation of Critical Infrastructures in Smart Cities

  • Leader : BENEDITO DONIZETI BONATTO
  • MEMBRES DE LA BANQUE :
  • ANTONIO CARLOS ZAMBRONI DE SOUZA
  • BENEDITO DONIZETI BONATTO
  • JOSÉ RAMON MARTÍ
  • LUIZ CARLOS PEREIRA DA SILVA
  • Data: 22 août 2022


  • Afficher le Résumé
  • Along with the development of society, productivity rates increase, causing the needs
    of the people to change. As a result, new technologies rise to fulfill the stability of the
    system and maintain the developing trend. This fact leads to the growth in the complexity of cities affecting their vulnerability and sustainability. The study and modeling
    of the interdependent relationships among cities´ critical infrastructures can provide
    not only optimal action plans for extreme events scenarios but also provide effective
    and strategic long-term planning to optimize the system towards the desired goal,
    which is the case of this research. This work provides a reliable model of the systems
    in a developing city that aims to represent the interdependent relationships in it, along
    with its variables, inputs, outputs, and possible modifiers. This plan will hopefully pave
    the way for the economic and energetic development of the city towards making it a
    smarter city and also showing that it is possible to make smart the existing, not
    planned, developing cities.

13
  • RENATA DE ALMEIDA RIBEIRO
  • Statistical Properties of PMU Signals - Phasor Measurement Unit

  • Leader : ROBSON CELSO PIRES
  • MEMBRES DE LA BANQUE :
  • CAMILA PAES SALOMON
  • ILDEMAR CASSANA DECKER
  • MARCOS NETTO
  • ROBSON CELSO PIRES
  • Data: 26 août 2022


  • Afficher le Résumé
  • This master’s thesis studies the statistical properties of voltage, current, and complex
    power measurements provided by phasor measurement units (PMUs). We use PMU mea-
    surements installed in an extra-high voltage transmission system, specifically the net-
    work operated by Companhia de Transmissão de Energia Elétrica Paulista (CTEEP), a
    transmission system operator in Brazil. Further, we also conduct an analysis using PMU
    measurements installed in low-voltage distribution systems, notably PMUs installed on
    University campuses across Brazil funded by the MedFasee project. Our analysis relies
    on the methodology recommended by the technical literature in signal processing. We
    pay particular attention to the fact that the standard deviation of errors associated with
    measurements expressed in rectangular coordinates decisively impacts the performance of
    bad-data processing algorithms. Hence, we evaluate the performance of bad-data process-
    ing algorithms formulated in the complex plane. We perform this evaluation on two state
    estimators based on the weighted least squares (WLS) method. The first state estimator
    follows the classical formulation and only uses measurements from the supervisory con-
    trol and data acquisition (SCADA) system. The second state estimator relies on a hybrid
    formulation, which allows us to use SCADA and PMU measurements.
    Key-words: Measures expressed in rectangular coordinates, PMU, hybrid state estima-
    tors.

14
  • ALINE AIRES TEIXEIRA
  • Controller Fuzzy Type 2 with Programming in Verilog of the Functions Membership

  • Leader : GABRIEL ANTONIO FANELLI DE SOUZA
  • MEMBRES DE LA BANQUE :
  • GABRIEL ANTONIO FANELLI DE SOUZA
  • ROBSON LUIZ MORENO
  • TALES CLEBER PIMENTA
  • THIAGO POUZA MUSSOLINI
  • Data: 29 août 2022


  • Afficher le Résumé
  • The fuzzy type-2 fuzzy inference system presents a superior performance in relation to
    other methods for applications in systems with uncertainty. This work presents the architecture of a SIF type-2 that aims to use the trapezoidal membership function that
    ensures faster and simpler circuits. The architecture implemented in FPGA consists of
    five blocks, fuzzifier, inference, rule base, type-reductor and defuzzifier. The hardware
    presented consists of two 8-bit inputs with three trapezoidal membership functions for
    each input, nine rules and an 8-bit output with three membership functions. The Verilog
    implementation results are compared with the same architecture implemented in Matlab®
    using the Toolbox for type-2 fuzzy.

15
  • EDSON FERNANDO MACHADO SATO
  • Arc Flash and Incident Energy in Industrial Power Systems

  • Leader : JOSE MARIA DE CARVALHO FILHO
  • MEMBRES DE LA BANQUE :
  • JOSE MARIA DE CARVALHO FILHO
  • LUIS HENRIQUE LOPES LIMA
  • PAULO MARCIO DA SILVEIRA
  • Data: 11 oct. 2022


  • Afficher le Résumé
  • Although the massive use of electricity in industry began at the end of the 19th century, the first electric arc thermal effects estimating method was only proposed in the 1980s. In the following decades, several works contributed to increase the knowledge about the phenomenon and to improve the methods to quantify it. The IEEE Std 1584 first edition was published in 2002, being the first incident energy calculation dedicated technical standard. This standard, which has become the industry most popular method, had its second edition published at the end of 2018, with significant changes. A new mathematical model was proposed, including parameters that were not measured before, in addition to long equations, which manual calculation may be considered impractical. In this context, this work presents an IEEE Std 1584-2018 method incident energy calculation script development and its application in two case studies. The first case study illustrates the parameter evaluation to carry out a low voltage controlgear incident energy study, ending with a comparison between the 2018 Edition results with those of the 2002 Edition. The second case study proposes a roadmap for carrying out an incident energy dynamic study that considers multiple sources and the rotating machines short-circuit contribution ac decrement, concluding with a comparison between the results considering the ac decrement with the results in which it is neglected, and a discussion of the situations in which the effort to carry out a dynamic study can be justified.

16
  • UCHENNA GODSWILL ONU
  • Integrated Design of Photovoltaic Power Generation Plant with Pumped Hydro Storage System and Agricultural Facilities in Uhuelem-Amoncha African Community

  • Leader : ANTONIO CARLOS ZAMBRONI DE SOUZA
  • MEMBRES DE LA BANQUE :
  • ANTONIO CARLOS ZAMBRONI DE SOUZA
  • BENEDITO DONIZETI BONATTO
  • ELIANE VALENCA NASCIMENTO DE LORENCI
  • MIGUEL CASTILLA
  • Data: 26 oct. 2022


  • Afficher le Résumé
  • Seasonal and location dependence of renewable energy resources have limited their applications in power generation. Energy storage systems are promising solutions to the intermittence of renewable energy resources. Rural electricity grids are faced with economic sustainability challenges due to low power demand and poverty. As countries hopefully pass through various stages of development, their needs change. The electricity needs of developing countries surely differ from those of developed economies. Most of the global population without access to electricity, and all the consequences of it, is found in developing countries. Energy access is undoubtedly a significant catalyst for development. Developed countries mainly require technologies to ensure energy security, resilience, and occasionally emission control. Therefore, microgrids are emerging technologies capable of supporting the diverse needs of various stages of development. For example, a rural grid design around economic drivers like agriculture and micro industries can mitigate poverty and improve economic sustainability of rural grids. This study presents an Integrated Design of Photovoltaic Power Generation Plant with Pumped Hydro Storage System and Agricultural Facilities in Uhuelem-Amoncha African Community. The design explored the natural availability of water body in an elevated settlement area that offers a natural storage height for hydro energy storage. HOMER (Hybrid Optimization of Multiple Energy Resources) software was deployed to optimize the design.
    The designed photovoltaic power generation plant has a nominal capacity of 221 kW. The simulated results show the power supply probability of the plant as 99.9%. The cost of energy (COE) offered by the design is 0.456 [US$/kWh] which is 82% lower than the current cost of energy in the project community based on generation through petrol generators. The System has 100% renewable energy penetration. The plant is designed to power 50 households with a daily domestic energy consumption of 4.46 [kWh] each. The plant capacity also covers the irrigation water requirement of 50 acres of corn farms. A total of 100 units of designed intelligent pest control system will also be powered by the plant. A community refrigeration scheme of 27 [m3] equivalent volume is part of the plant design load. The benefits from the irrigation, water supply, pest control and refrigeration scheme will enhance the community’s socio-economic development and sustain the investment. Quantifying the integral socio-economic and environmental benefits is a subject of a future research.


17
  • MATEUS GOMES DE SIQUEIRA E SALLES
  • Feasibility analysis of application of energy sustainability solutions on the Unifei campus

  • Leader : BENEDITO DONIZETI BONATTO
  • MEMBRES DE LA BANQUE :
  • BENEDITO DONIZETI BONATTO
  • JOSE WANDERLEY MARANGON LIMA
  • TIAGO RODARTE RICCIARDI
  • VICTOR EDUARDO DE MELLO VALERIO
  • Data: 25 nov. 2022


  • Afficher le Résumé
  • The development of new technologies and maturing of rules, norms and laws refer-ring to the electricity sector have been in constant evolution since the beginning of its conception. Over the years, the emergence of new energy solutions, as well as improvements in the power sector regulation, have provided the system's growth in a sustainable way. In this context, when considering the possible energy solutions and optimizations, this dissertation seeks to explore the options for electricity con-sumption at the Federal University of Itajubá - UNIFEI, to present the most sustain-able model and that seeks to better apply the power and market solutions. The cas-es evaluated will verify the use of Photovoltaic Solar Generation and/or Energy Storage, as well as the transition between the Regulated Contracting Environment - ACR and the Free Contracting Environment - ACL.

18
  • OSCAR MANUEL TORRES LARROSA
  • VOLTAGE STABILITY ANALYSIS IN POWER SYSTEMS, CONSIDERING THE INSERTION OF RENEWABLE SOURCES

  • Leader : GABRIEL ANTONIO FANELLI DE SOUZA
  • MEMBRES DE LA BANQUE :
  • ANTONIO CARLOS ZAMBRONI DE SOUZA
  • DIOGO MARUJO
  • ELIANE VALENCA NASCIMENTO DE LORENCI
  • RENAN SOUZA MOURA
  • Data: 8 déc. 2022


  • Afficher le Résumé
  • This work presents the development of a methodology that allows identifying the reliable penetration levels of non-conventional renewable generation, such as the case of photovoltaic generation to the Transmission System of Paraguay. To achieve this, a methodology is developed for the quantification of current stability margins, the recognition of critical areas of the system, and the identification of candidate buses for possible reinforcements of the system, such as the insertion of photovoltaic solar generation, and thus, obtaining an evaluation of the technical performance of the system. For this reason, some classic voltage stability tools are applied, such as the Load Margin (MC), obtained through the PV curves and the Tangent Vector (VT). Likewise, this methodology allows obtaining the positive impacts of a greater photovoltaic penetration, such as a significant increase in the MC, as well as eventual negative effects considering the decrease in the rotational inertia of the system. On the other hand, the work also includes an investigation about the social effects of the insertion of large generation works in isolated regions of the analyzed system, where results indicate that access to electricity in isolated and vulnerable communities contributes enormously to facilitate the economic and social integration of the population, leaning towards tangible sustainable development. Finally, as a conclusion, the methodology for the proposed analysis is valid, and up to 15% of photovoltaic generation can be safely installed in the Paraguayan System

19
  • HUGO OLIVEIRA VILAS BOAS
  • Application of a 24-pulse AC-DC converter as Workaround for Power Quality Improvement within the Context of Aircraft Electrical Systems

  • Leader : GABRIEL ANTONIO FANELLI DE SOUZA
  • MEMBRES DE LA BANQUE :
  • ADRIANA APARECIDA DOS SANTOS IZIDORO
  • CHRISTEL ENOCK GHISLAIN OGOULOLA
  • GABRIEL ANTONIO FANELLI DE SOUZA
  • ROBSON BAUWELZ GONZATTI
  • Data: 12 déc. 2022


  • Afficher le Résumé
  • This work, with the objective of improving the quality of electric power (QEE) in
    MEA (More Electric Aircraft) distribution systems operating with variable frequency
    (360 – 800 Hz), addresses an application of a 24-pulse converter system (SC- 24P),
    previously developed by the research group for use in HVDC (High Voltage Direct
    Current) transmission systems. Usually, the converter systems used in MEA systems,
    for AC–DC conversion, are of the 12-pulse type (SC-12P). However, this type of
    converter technically does not meet harmonic distortion standards for MEA
    applications and therefore must be used in conjunction with AC and DC filters. In
    addition, the weight and volume occupied by the filters clearly bring some
    disadvantages to modern MEA systems.
    In order to overcome the disadvantages offered by the traditional system, this
    dissertation proposes the use of the SC-24P to reduce the filters used in conventional
    MEA systems and to improve the power quality of the system as a whole. Theoretical
    analyzes of the SC-24P, regarding the profiles and harmonic content of the AC currents
    and DC voltages for both converters, are briefly described through established
    equations, which made it possible to partially prove the research conducted in this
    dissertation. The calculations processed through the theoretical analyzes are done
    using the MathCad program. The advantages and performance of the employed SC24P compared to the traditional SC-12P are exposed via computational simulations
    carried out in the Matlab/Simulink environment.
    The results obtained from the SC-24P in terms of %THD (< 3%) of AC current,
    DC voltage ripple amplitude and other QEE indices, for the 360 Hz and 800 Hz
    frequencies, meet the RTCA-Aeronautical Standards. DO-160F and MIL-STD-704F,
    respectively. On the other hand, with the lack of laboratory resources regarding the
    availability of a power supply for the level of operational frequencies treated in
    simulations, a reduced-scale prototype was implemented using the power supply
    network at 60 Hz. The results meet the requirements of IEEE 519 and prove the
    application of the converter used only in industrial electrical systems, for driving
    rotating electrical machines. The synthesis of the results treated and discussed in this
    work confirms the applicability of the SC-24P in MEA systems and demonstrates a
    promising research to be explored for future developments.

20
  • GUILHERME FERREIRA DA MATA
  • CRITICAL ANALYSIS OF THE EVOLUTION OF THE REGULATORY REMUNERATION BASE OF ELECTRICITY UTILITIES IN THE COUNTRY AND PROPOSAL FOR AN INTEGRATED FRAMEWORK FOR REGULATED ASSET MANAGEMENT

  • Leader : BENEDITO DONIZETI BONATTO
  • MEMBRES DE LA BANQUE :
  • BENEDITO DONIZETI BONATTO
  • FERNANDA CASENO TRINDADE ARIOLI
  • GIANCARLO AQUILA
  • JOAO GUILHERME DE CARVALHO COSTA
  • Data: 14 déc. 2022


  • Afficher le Résumé
  • The Brazilian electricity sector is going through a revolution in face of modernization challenges, needs for investments in smart grids, insertion of new technologies and distributed energy resources. In this context, it is relevant to discuss the mechanisms to stimulate the efficiency of the investments made by the Electricity Distribution Companies (DisCos), as well as the formulation of practices and concepts (a framework) that help companies in the electricity sector to act. According to a regulatory strategy, capturing the incentives allowed, complying with regulatory requirements and seeking to maximize the benefits for the entire Brazilian society, providing transparency and lower tariff, since the costs of energy distribution activities are directly related to the management of the company's assets. Thus, when it comes to regulatory asset management, there are several complex challenges to be solved or optimized. On one hand, the regulated companies' focus is to increase their remuneration base through investments in the network according to the concession, contracts, and on the other hand, the regulator's focus is to ensure that only prudent investments are remunerated and to guarantee reasonable tariffs. This scenario is challenging for both sides. Despite the maturity and conceptual evolution of the existing methodologies for asset management, the daily practice in concessionaires, especially energy distributors, struggles against a variety of approaches to traditional practices and, mainly, with the lack of an integrated approach that takes into account the complexity of the regulatory environment, and it is essential for these concessionaires to meet and understand this environment. One of the main contributions of this work is the formulation of an integrated regulatory asset management framework for distribution companies. Based on regulatory requirements, the investment remuneration mechanism and practices adopted by Brazilian distributors, the proposed framework unifies practices and presents concepts and standards that must be adopted considering the regulatory perspective in the management of their remuneration base.

21
  • MIGUEL MARQUES DE PAIVA ESPER
  • Service of reconfiguration to IoT devices.

  • Leader : DANILO HENRIQUE SPADOTI
  • MEMBRES DE LA BANQUE :
  • DANILO HENRIQUE SPADOTI
  • EDVARD MARTINS DE OLIVEIRA
  • GABRIEL LOBÃO VASCONCELOS FRÉ
  • REINALDO LIMA DE ABREU
  • Data: 14 déc. 2022


  • Afficher le Résumé
  • This work presents an optimization model for sending telemetry from IoT devices, using
    the Twin Device tool present in Microsoft’s cloud server services platform, called Azure.
    The optimization is done through a server, developed in Python, which interprets the
    telemetry received, defines the current state of the device and updates the settings of
    the device and emits it through Twin Device. The result in normal operating states was
    a drastic decrease in the number of packets and consequently a smaller volume of data
    trafficked on the network, already in a critical state, the amount of packets increased and
    consequently a considerably greater volume trafficked through the network.

22
  • RAFAEL MAGLIONE AOUN
  • Evaluation of DER's control strategies impact on the dynamic response of power systems

  • Leader : ANTONIO CARLOS ZAMBRONI DE SOUZA
  • MEMBRES DE LA BANQUE :
  • ANTONIO CARLOS ZAMBRONI DE SOUZA
  • BRUNO de NADAI NASCIMENTO
  • LUIZ CLAUDIO DE ARAUJO FERREIRA
  • MAURICIO CAMPOS PASSARO
  • PAULO FERNANDO RIBEIRO
  • Data: 14 déc. 2022


  • Afficher le Résumé
  • Load modeling in power systems is a crucial aspect for stability studies. The analysis of certain dynamic phenomena requires proper load modeling. Fault Induced Delayed Voltage Recovery (FIDVR) is directly related to Residential Air Conditioner (RAC) stalling. Therefore, the modeling of induction motor loads is essential to this analysis. Delayed voltage recovery in the system can result in delayed power recovery in inverters connected to the transmission system, responsible for connecting photovoltaic and wind power plants to the Brazilian Interconnected Power System (BIPS). In the last few years, there has been a huge growth of Distributed Energy Resources (DER) in Brazil. In power systems around the world, both modern and legacy ride-through settings coexist. Inverters with legacy settings are more likely to disconnect in systemic events. The modeling of induction motors in the Acre-Rondonia system leads to a deterioration of this system’s dynamic performance, which can lead to collapse. DER’s voltage support can contribute to post-fault system voltage recovery, mitigating the delay caused by RAC stalling and avoiding collapse. For this to happen, more robust ride-through settings are required, avoiding inverter disconnection. Moreover, dynamic voltage support and reactive current priority requirements must be demanded from inverters that connect to the system.

23
  • ANDRÉ SOARES DA SILVA
  • Solution of the Power Flow Problem in the Complex Plane Via Conjugate Gradient Methods

  • Leader : ROBSON CELSO PIRES
  • MEMBRES DE LA BANQUE :
  • FABRICIO SILVEIRA CHAVES
  • ILDEMAR CASSANA DECKER
  • ROBSON CELSO PIRES
  • Data: 16 déc. 2022


  • Afficher le Résumé
  • The technical literature in numerical analysis offers several alternatives of iterative methods for the solution of nonlinear optimization problems applied to the energy industry. However, when it comes to iterative methods applied to nonlinear power flow, the Newton-Raphson iterative method and its variations are practically unanimity. The work proposal of this master's thesis aims to investigate the performance of nonlinear Complex Bi-Conjugate Gradient Methods (CBiCG) in their application to power flow problems, in comparison with the classical formulation, using the Newton- Raphson in polar coordinates in the domain of real numbers. These methods, however, were implemented in the complex domain through the use of the Generalized Wirtinger calculus and the extension of Taylor series to the complex domain. The main motivations for this approach are that the conjugate gradient methods are first order and do not require factoring the Jacobian matrix as is done in the traditional Newton-Raphson method, thus reducing the computational effort required to obtain the solution. In addition, in view of the current computational complexity, there has been a tendency for processor architecture to incorporate SIMD (Single Instruction, Multiple Data), which refers to a set of operations for efficiently handling a large amount of data in parallel, using a vector or matrix processor, suitable for the algebra of complex numbers.

Thèses
1
  • EMERSON ASSIS DE CARVALHO
  • Estimating the Family Bias to Autism: A Bayesian Approach

  • Leader : GUILHERME SOUSA BASTOS
  • MEMBRES DE LA BANQUE :
  • ROBERTO HIROCHI HERAI
  • EDMILSON MARMO MOREIRA
  • GUILHERME SOUSA BASTOS
  • JOAO PAULO REUS RODRIGUES LEITE
  • LUCELMO LACERDA DE BRITO
  • RICARDO ZORZETTO NICOLIELLO VENCIO
  • Data: 21 févr. 2022


  • Afficher le Résumé
  • Autism is an age- and sex-related lifelong neurodevelopmental condition characterized primarily by persistent deficits in core domains such as social communication. It is estimated that ≈ 2% of children have some ASD trait. The autism etiology is mainly due to inherited genetic factors (>80%). The importance of early diagnosis and interventions motivated several studies involving groups at high risk for ASD, those with a greater predisposition to the disorder. Such studies are characterized by evaluating some characteristics of the individual itself or the family members of diagnosed individuals, mainly aiming to predict a future diagnosis or recurrence rates. One of the primary goals of Artificial Intelligence is to create artificial agents capable of intelligent behaviors, such as prediction problems. Prediction problems usually involve reasoning with uncertainty due to some information deficiency, in which the data may be imprecise or incorrect. Such solutions may seek the application of probabilistic methods to construct inference models. In this thesis, we will discuss the development of probabilistic networks capable of estimating the risk of autism among the family members given some evidence (e.g., other family members with ASD).
    In particular, the main novel contributions of this thesis are as follows: the proposal of some estimates regarding parents with ASD generating children with ASD; the highlighting regarding the decrease in the ASD prevalence sex ratio among males and females when genetic factors are taken into account; the corroboration and quantification of past evidence that the clustering of ASD in families is primarily due to genetic factors; the computation of some estimates regarding the risk of ASD for parents, grandparents, and siblings; an estimate regarding the number of ASD cases in a family sufficient to attribute the ASD occurrences to the genetic inheritance; the assessment of some estimates for males and females individuals given evidence in grandparents, aunts-or-uncles, nieces-or-nephews and cousins; and the proposition of some estimates indicating risk ranges for ASD by genetic similarity.

2
  • ANDRE BERNARDI
  • ESTIMAÇÃO DA PROPORÇÃO DE ÁGUA NO ETANOL COMBUSTÍVEL ATRAVÉS DA ANÁLISE DA ASSINATURA ACÚSTICA EM SINAIS ULTRASSÔNICOS

  • Leader : LUIZ EDUARDO BORGES DA SILVA
  • MEMBRES DE LA BANQUE :
  • CARLOS EDUARDO TEIXEIRA
  • ERIK LEANDRO BONALDI
  • GISCARD FRANCIMEIRE CINTRA VELOSO
  • ISMAEL NORONHA
  • LUIZ EDUARDO BORGES DA SILVA
  • ROBSON BAUWELZ GONZATTI
  • RONDINELI RODRIGUES PEREIRA
  • Data: 4 mars 2022


  • Afficher le Résumé
  • The end of price controls on fuels led to an increase in competitiveness between distribution
    companies and resellers, which aggravated the practice of adulteration of fuels, thereby
    aiming at illicit gains and tax evasion. The most common adulteration of ethanol is
    accomplished by adding water, which is the simplest practice of adulteration. Karl Fischer's
    technique is one of the most reliable to measure the water content in ethanol and is
    recommended by the National Agency of Petroleum, Natural Gas and Biofuels (ANP), a
    regulatory agent, to assess the water levels present in ethanol. Although this approach offers
    good precision and good detail regarding the presence of water, it has disadvantages such as
    the need for sample collection, long analysis time, in addition to the need for specialized
    laboratory and labor. The ultrasonic technique can detect moisture in ethanol, either
    invasively, through samples, or non-invasively, obtained directly from the walls of a pipe filled
    with liquid. Based on this information, the present work aims to propose digital signal
    processing techniques to analyze and quantify the presence of moisture in ethanol samples
    through the manipulation of ultrasonic signals that had contact with the mixture in the liquid
    phase and had their characteristics altered by the presence of water. To identify and quantify
    water levels in the ethanol-water mixture, a combination of the Principal Component Analysis
    (PCA) and Singular Spectrum Analysis (SSA) techniques is used. This methodology resulted in
    the proposition of a new score, which relates to the information of the ethanol / water ratio
    present in the mixture, allowing the application of the technique to analyze this information in
    a non-invasive way, and in a wider range . This thesis presents a non-invasive methodology to
    characterize, quantify and classify the presence of moisture in fuel ethanol. The results found
    were promising when relating the proposed score to the presence of moisture in ethanol to a
    greater or lesser degree. Experiments performed demonstrate the feasibility of the technique
    and pave the way for a new methodology for monitoring totally non-invasive conditions.

3
  • GIULIA OLIVEIRA SANTOS MEDEIROS
  • Efficiency analysis for the Brazilian electric utilities

  • Leader : JOSE WANDERLEY MARANGON LIMA
  • MEMBRES DE LA BANQUE :
  • ANDERSON PAULO DE PAIVA
  • JOSE WANDERLEY MARANGON LIMA
  • JOSÉ FRANCISCO MOREIRA PESSANHA
  • LUANA MEDEIROS MARANGON LIMA
  • PAULO ROTELLA JUNIOR
  • Data: 25 mars 2022


  • Afficher le Résumé
  • The electricity distribution sector in Brazil has the characteristic of a natural monopoly and needs economic regulation. The mechanism adopted for tariff regulation is the Periodic Tariff Review (RTP), carried out by the National Regulatory Agency. Currently, the efficiency analysis method applied at RTP is the Data Envelopment Analysis (DEA), already used by other countries in the evaluation of efficiency in energy utilities. Utilities classified as inefficient by the DEA must direct their efforts to win efficiency by looking at practices from the utilities classified by efficient by the DEA. This study proposes an efficiency analysis focused on improving the current methodology at RTP and suggests tools that may be useful in providing strategies to improve efficiency. The analyzes presented here focus on two levels: sectorial and corporate. At the sectorial level, an efficiency analysis is proposed, in which each utility is considered as a Decision-Making Unit (DMU) in the DEA and compared with each other. This efficiency analysis between utilities delimited the database defined by the regulator. The study also applies the concept of 'clustering' the set of DMUs by the k-means method, showing the effect that a reduction of DMUs` set causes in the efficiency analysis. Finally, the impact of DEA efficiency is measured quantitatively on the utilities' regulatory operating costs (COR). At the corporate level, an innovative internal benchmarking is proposed, named here self-efficiency analysis. This analysis splits the utility into smaller parts (regional), and these parts are considered the DMUs in the DEA. The idea of splitting the concession area into smaller areas is to incorporate the effect of environmental characteristics (such as lightning incidence and vegetation height) in the efficiency analysis. The thesis presents a case study for a utility in São Paulo. The self-efficiency analysis, therefore, defines efficiency gain strategy by indicating the most inefficient areas inside the utility. The study also applies two other benchmarking techniques, the Cross-efficiency Analysis and the Ratio-based Efficiency Analysis. The CEA and REA studies bring new efficiency indicators for efficiency analysis between utilities and self-efficiency analysis.

4
  • MATHEUS SÊDA BORSATO CUNHA
  • 5G NR Optical-Wireless System with a Multi-Wavelength Transmitter in Integrated Optics

  • Leader : DANILO HENRIQUE SPADOTI
  • MEMBRES DE LA BANQUE :
  • EVANDRO CONFORTI
  • ARISMAR CERQUEIRA SODRÉ JUNIOR
  • DANILO HENRIQUE SPADOTI
  • JOSE ANTONIO JUSTINO RIBEIRO
  • MATEUS AUGUSTO FAUSTINO CHAIB JUNQUEIRA
  • ROBERTO SHIGUERU NOBUYASU JUNIOR
  • Data: 29 mars 2022


  • Afficher le Résumé
  • This work addresses a solution for the implementation of radio over fiber (RoF - radio-over-fiber) systems for applications in fifth-generation (5G) wireless networks and future generations. The proposed solution is demonstrated with the application of a multiwavelength transmitter (MWT – multiwavelength transmitter) integrated into an indium phosphide platform (InP – indium phosphide), as a source for generating optical carriers. First, the photonic integrated circuit (PIC) and characterization of the MWT are presented. The PIC integrates eight tunable wavelength lasers, aiming to reduce the complexity and dimensions of the transmitter, allowing for compact, high-performance, and smaller 5G solution cost.
    After the characterization, a multi-band 5G optical fronthaul is implemented using two 5G new radio (NR) signals and one LTE-A signal. The signals are evaluated in two distinct scenarios, as a function of the root mean square error vector magnitude (EVMRMS), according to the requirements of 3GPP Release 15. In the first phase, three optical carriers in C-band are independently modulated with three mentioned RF signals featuring wavelength division multiplexing, whereas subcarrier multiplexing is applied to the second scenario to jointly modulate the three RF signals into a single optical carrier. Gbit/s throughput is demonstrated to validate the applicability of the integrated MWT to allow multiple applications and/or diverse RF standards.
    The PIC transmitter is implemented in wireless optical communication systems. The first implementation refers to a system based on the convergence between optical networks and RF networks, called fiber-wireless (FiWi) system. In this system, three RF signals, in 4G/5G standards, are simultaneously transported over a 12.5 km long RoF link. RF transmissions in the wireless medium are demonstrated using a 10 m long indoor picocell-like link and a 115-m long realistic outdoor link. The second proposal presents a 12.5 km RoF system followed by a 1.5 m free space optics (FSO) link, targeting the end-user access network. In this proof of concept, an M QAM signal is transmitted on only one MWT channel. The received signals in both implementations comply with the requirements of 3GPP Release 15, in terms of EVMRMS, and show a total throughput of 1.36 Gbit/s and 230 Mbit/s in the scenarios of 10 m and 115 m, respectively, and a throughput of 160 Mbit/s for the link in FSO.

5
  • CÉSAR WILLIAM VERA CASAÑAS
  • A biasing technique for a CMOS current comparator

  • Leader : ROBSON LUIZ MORENO
  • MEMBRES DE LA BANQUE :
  • DALTON MARTINI COLOMBO
  • GUSTAVO DELLA COLLETTA
  • LEONARDO BRESEGHELLO ZOCCAL
  • OSAMU SAOTOME
  • PALOMA MARIA SILVA ROCHA RIZOL
  • ROBSON LUIZ MORENO
  • Data: 14 avr. 2022


  • Afficher le Résumé
  • In this work a technique to bias a CMOS current comparator is presented. The current
    comparator circuit uses the flipped voltage follower (FVF) block as input stage, and a
    cascode structure is proposed to bias properly this stage. Alternatives to bias the input
    block are presented, demonstrating the trade-off between the response time and the input
    impedance of the circuit. The circuit was developed using the CMOS technology of the
    Taiwan Semiconductor Manufacturing Company (TSMC) 0.18 µm process. The postlayout simulation results show that the current comparator, with the proposed structure
    to bias the input stage, exhibits a propagation time of 7.5 ns with a power consumption of
    47 µW when the input is a pulsed current amplitude ±2 µA with a frequency of 50 MHz.
    The input impedance value is 50 Ω at the operating frequency. The minimum current, at
    low frequencies, that the circuit can detect is 200 pA. The cascode structure, proposed
    to bias the FVF block, provides a voltage value of 1.01 V with a coefficient of variation
    of ±0.001%. The results of the characterization of the manufactured prototype confirm
    that the current comparator, with the proposed technique to bias the input circuit, is
    appropriate and functional.

6
  • VERONICA ETCHEBEHERE SANTIAGO
  • Locational Tariff Structure for Radial Network Fixed Costs in a DER Context

  • Leader : JOSE WANDERLEY MARANGON LIMA
  • MEMBRES DE LA BANQUE :
  • DELBERIS ARAUJO LIMA
  • DOREL SOARES RAMOS
  • EDUARDO CRESTANA GUARDIA
  • JOSE WANDERLEY MARANGON LIMA
  • LUANA MEDEIROS MARANGON LIMA
  • Data: 19 mai 2022


  • Afficher le Résumé
  • The regulation of Distributed Energy Resources (DERs) has cast doubt on the
    sustainability of utility business models. The impact of net-metering, and network
    charge rebates for distributed generation (DG) have been questioned because of the
    cross-subsidies that result between passive consumers and DG investors. Besides DG
    investors, other new entrants such as owners of energy storage resources and
    electrical vehicles are creating challenges for the regulation of distribution service
    pricing. This work addresses the debate by comparing several different distribution network
    pricing models from the literature. It suggests modifications to these methodologies to
    adapt them as we transition from a distribution sector comprising passive users to one
    in which users are active agents. It considers the design principles governing each
    tariff, from the perspective of simplicity, economic signalling, and revenue
    reconciliation. Results are presented of simulations performed with different arrangements of
    alternative energy generators and energy stores, using an actual feeder from a
    distribution company in Brazil. An analysis of these results is provided that suggests a
    combination of locational and time-of-use rates can provide effective economic signals
    to these new types of system user.

7
  • BRUNO SILVA TORRES
  • Multi-Agent System for Self-Healing to Smart Grids

  • Leader : LUIZ EDUARDO BORGES DA SILVA
  • MEMBRES DE LA BANQUE :
  • ALEXANDRE RASI AOKI
  • CAMILA PAES SALOMON
  • CARLOS HENRIQUE VALERIO DE MORAES
  • CLAUDIO INACIO DE ALMEIDA COSTA
  • LUIZ EDUARDO BORGES DA SILVA
  • RONALDO ROSSI
  • Data: 19 mai 2022


  • Afficher le Résumé
  • Electricity distribution systems represent the final link between energy-generating companies and consumers. Having radial characteristics, they have lower reliability, so a failure in some components causes the interruption of the power supply. Even with the development of new technologies to improve the operation and maintenance of these systems, losses and interruptions are inevitable. When the power supply is out of the supply due to a failure, the system must be re-established to meet the largest number of loads safely and in the shortest possible time interval. The current distribution network is at a stage of development known as the smart grid, using advances in information and communication technologies. This thesis presents a contribution to implementing self-healing strategies of distribution systems in a decentralized way, which brings as main advantages the good cost-benefit ratio, the improvement in reliability, and the possibility of incremental expansion of the system. The proposed system is based on an intelligent multiagent structure, in which each agent has a logical structure that is classified as hierarchical and hybrid. Hierarchical, because the actions are divided into four logical levels: instinct, normal operation, abnormal operation, and optimization and prediction. And hybrid, because in addition to the logical part, the rules can trigger numerical routines that help in the agents' decision-making process. In addition to self- healing, several demand response functions are part of the agent, such as overload, load cutting, load prioritization, and load evolution. These functions allow the self- healing squealing solution found to consider the current system load and its evolution in the coming hours. In the proposed multiagent structure, agents only communicate with agents adjacent to it, reducing the need for a more robust communication system covering long distances. It is also proposed a structure of communication and exchange of messages with redundancy and effectiveness, mitigating the risks of erroneous communication between agents. Even with this type of communication, agent action occurs locally but is based on data received from multiple (even non-adjacent) system agents. The agent also implements functions that allow it to interact with the traditional protection systems of urban distribution networks, monitoring the operation of fuses, reclosers, and sectionalizers, allowing the advantages of an intelligent electrical network, even in a still incomplete system. The proposed multiagent system is validated through several examples using energy distribution systems and the computational implementation of the proposed hybrid hierarchical intelligent agents working together.

8
  • ALESSANDRO AUGUSTO NUNES CAMPOS
  • Authentication for Integrated Circuit and Devices Using Blockchain and Physical Unclonable Functions

  • Leader : TALES CLEBER PIMENTA
  • MEMBRES DE LA BANQUE :
  • HAMILTON JOSÉ MENDES DA SILVA
  • DALTON MARTINI COLOMBO
  • GABRIEL ANTONIO FANELLI DE SOUZA
  • ROBSON LUIZ MORENO
  • TALES CLEBER PIMENTA
  • Data: 27 mai 2022


  • Afficher le Résumé
  • Secure components and devices have always been and always will be a challenge for the electronics industry. In this sense, there is a constant and growing demand for new solutions that can allow reliability in the use and authenticity of components and devices. The end user is not able to assess the existing risk, much less if the component or device is reliable in several aspects, mainly improper access to its information. This work presents a new approach with the integration of two tech nologies: Blockchains networks, which implement a kind of decentralized and inviolable database, which can increase resilience, security and guarantee against the alteration of the information registered in its structure; Physical Unclonable Functions (PUF), which allow the generation of a strong cryptographic key, since they use unique physical characteristics of each semiconductor component, considerably increasing security, simplicity, protection of industrial property and the opportunity for remote authentication of devices. The contribution here is in the integration of existing technologies, in order to obtain an innovative solution of authentication and cyber security for the internet of things and others devices.

9
  • PAULO HENRIQUE FERETTI
  • NON-ISOLATED DC-DC CONVERTERS WITH LARGE CONVERSION RATE BASED ON MULTI-STATE SWITCHING CELL AND VOLTAGE MULTIPLIER CELLS

  • Leader : ENIO ROBERTO RIBEIRO
  • MEMBRES DE LA BANQUE :
  • RENÉ PASTOR TORRICO BASCOPÉ
  • BENEDITO DONIZETI BONATTO
  • FALCONDES JOSE MENDES DE SEIXAS
  • FERNANDO LESSA TOFOLI
  • GABRIEL ANTONIO FANELLI DE SOUZA
  • LUIS HENRIQUE DE CARVALHO FERREIRA
  • Data: 6 juin 2022


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  • This work presents the study and design of a family of non-isolated high step-up dc-dc converters, based on the multi-state switching cell (MSSC) and voltage multiplier cells (VMCs). These converters can be used in applications such as uninterruptible power systems and electric vehicles, which employ a few kilowatts power and require high voltage gain. Inherent advantages in the proposed topologies include reduced current and voltage stresses on the semiconductors, improved thermal distribution, good current sharing among the phases, and reduced dimensions of filter elements. Another relevant aspect is that the derived converters present modularity in terms of the possibility of extending not only the voltage gain, but also the rated power. A comprehensive theoretical analysis of the 4SSC-VMC boost converter, deriving from the proposed family, is performed. Experimental results obtained from a 1.3 kW prototype are presented and discussed to validate the theoretical assumptions.

10
  • MATEUS MENDES CAMPOS
  • Ultrasonic-Capacitive Hybrid System for Fuel Oil Quality Analysis

  • Leader : LUIZ EDUARDO BORGES DA SILVA
  • MEMBRES DE LA BANQUE :
  • CARLOS EDUARDO TEIXEIRA
  • GERMANO LAMBERT TORRES
  • GISCARD FRANCIMEIRE CINTRA VELOSO
  • JOAO ONOFRE PEREIRA PINTO
  • LUIZ EDUARDO BORGES DA SILVA
  • Data: 15 juin 2022


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  • Heavy fuel oils (HFO) are widely exploited to produce electric energy in Thermoelectric Power Plants (TPP), mainly due to the amount of heat released during its combustion. Economic factors also influence the use of HFO for energy generation, including the low cost of energy content, availability due to raw materials, ease of transport and storage, low operating investment costs, among others. The power to produce energy from HFO is defined by its calorific value (or heating value) and is linked to the quality of the fuel oil and the presence of contaminants, such as water. A fuel oil with properties different from those expected/specified can not only decrease the calorific value, but also can cause damage to the TPP equipment. Therefore, the analysis of the quality of fuel oils is of great importance for TPPs. This work proposes a methodology to estimate three parameters of the quality of fuel oils: the density, the water content in the oil and the calorific value. The proposed methodology has developed a system that has techniques such as ultrasonic, capacitive and temperature measurement to estimate quality parameters. The ultrasonic system is based on the propagation time of the ultrasonic waves to estimate two quantities, the speed of sound and the flow of the fluid. The capacitive system correlates the capacitance variation with the water content in oil, starting from the existing association between sensor, fuel oil and water. Temperature measurement data is used in conjunction with sound velocity data to compensate for the effect of temperature on the density estimation. Based on the temperature and velocity of sound information, and using a classification algorithm, a method was developed to recognize the existing similarity between the OC under analysis and the OC information from a database. With the result of the classification, the scores and the information from the database are obtained to estimate the density. Finally, the calorific value is calculated by associating the density and water content data. The results obtained from the tests were compared with data from laboratories and technical sheets of the OCs, reaching relative deviations lower than 1.0% and 0.5% for the density and calorific value, respectively.

11
  • GUILHERME GONÇALVES PINHEIRO
  • Power Flow Control using Series Voltage Source Converters for Distribution Grids

  • Leader : LUIZ EDUARDO BORGES DA SILVA
  • MEMBRES DE LA BANQUE :
  • CARLOS HENRIQUE DA SILVA
  • JOAO ONOFRE PEREIRA PINTO
  • LUIZ EDUARDO BORGES DA SILVA
  • ROBSON BAUWELZ GONZATTI
  • RONDINELI RODRIGUES PEREIRA
  • WILSON CÉSAR SANT`ANA
  • Data: 20 juin 2022


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  • This study presents an application for a series VSC (Voltage Source Converter) in distribution grids for power flow management. Series devices have been widely studied for FACTS (Flexible AC Transmission Systems), however, more recently these devices have gained increased interest in applications for loading balance in medium voltage distribution grids. As the number of distributed generation (DG) units increases, increasing the capacity and reliability of distribution grids, while maximizing the benefits of installed DGs and loading behavior, is an ever more important task. In this work we describe a test system and control proposals for a practical application of series converters interconnecting two distribution feeders at 13.8kV under load variation disturbances. This approach provides solutions when installed at the end of distribution lines by interconnecting two feeders, resulting in capacity increases in the feeders without needing grid reconfigurations using a small-rated series VSC.

12
  • GABRIEL HENRIQUE DE FARIA
  • Evaluation of Aging Factors of the Covered Cables of 15 kV Class and Its Impacts on the Insulation Coordination

  • Leader : ESTACIO TAVARES WANDERLEY NETO
  • MEMBRES DE LA BANQUE :
  • ALAN MELO NÓBREGA
  • ESTACIO TAVARES WANDERLEY NETO
  • GUSTAVO PAIVA LOPES
  • JOSE FELICIANO ADAMI
  • MARIA ELENA LEYVA GONZALEZ
  • RONALDO EUGENIO DE SOUZA FILHO
  • Data: 29 juin 2022


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  • Compact Distribution Network (CDN) provides a great reliability for the medium voltage electric system due to the polyethylene protection present in the cables, avoiding system interruptions caused by non-permanent contact between the cables and ground objects. Besides this, the reliability increase is also associated with the dielectric supportability increase of the system, considering the greater dielectric strength of the polyethylene in comparison with dielectric strength of the air. However, the polyethylene presents accelerated ageing in comparison with the glass and porcelain insulators, which are widely used in the conventional distribution network (without protection on the cables). The polyethylene degradation is even more accentuated in high temperature, humidity and pollution areas. Therefore, the polyethylene ageing may cause problems in the electric system, such as the increase of the maintenance, equipment replacement and short-circuits. On the other hand, there is a scarcity in the literature of laboratory methods capable of promoting the accelerated aging of the covered cables used in CDN. Most methods take into account the evaluation of other polymeric components and, often, the most effective methods are difficult to implement in the laboratory and have high costs. In this way, this work proposes two own methods to evaluate the aging of the covered cables, installed on polymeric insulators during the tests. The first ageing method consisted in the utilization of two factors: voltage application equal to the double of the system phase-ground voltage and pollution caused by salt fog. The second method added the thermic effect, due to the current induction in the cable, with the purpose to obtain 60ºC on its surface. To characterize the aging and evaluate the quality of the samples, were used in this work monitoring tests, divided into physicochemical tests and electrical test. The goal of the physicochemical tests is to determinate the ageing influence in the XLPE structure, analyzing the oxidation factor (IO), the activation energy (E) of the degradation process, the fusion heat (C) and the XLPE surface hydrophobicity. On the other hand, considering the electrical tests, this work evaluates the impact of the polyethylene (XLPE) ageing, present in the covered cables, in the CDN insulation coordination of 15 kV voltage class. The electric tests used were: partial discharge measurement, leakage current (CF) measurement and lightning withstand. Considering the results, the second ageing method caused material degradation, increasing the oxidation factors and reducing the system lightning withstand considering positive voltage impulses. On the other hand, regarding the first method, although the samples tested presented punctual damages during the test, it was not observed structural changes capable of causing reductions in the lightning withstand of the system. Analyzing the results, it was possible to equate the trend of the parameters IO, CF and Disruptive Voltage, in relation to the aging exposure time, using linear regression. Besides this, it was verified that, even aged, the lightning withstand of the system is higher than the Basic Impulse Level (BIL) of the system. The critic problem for the CDN is the failures events caused by superficial discharge on the material, in the form of erosion and tracking. Therefore, this work presents an accelerated ageing test method and evaluates the quality of covered cables.

13
  • LEONARDO DE CARVALHO VIDAL
  • Análise de viabilidade econômica e ambiental da utilização de energia elétrica com sistema Shore Power em um contexto para instalações portuárias Brasileiras

  • Leader : TALES CLEBER PIMENTA
  • MEMBRES DE LA BANQUE :
  • OSVALDO AGRIPINO DE CASTRO JUNIOR
  • PAULO ANDRÉ DIAS JACOME
  • GABRIEL ANTONIO FANELLI DE SOUZA
  • GERALDO LUCIO TIAGO FILHO
  • NEWTON NARCISO PEREIRA
  • TALES CLEBER PIMENTA
  • Data: 6 juil. 2022


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  • Shore Power is one of the names given to the process of using the electrical energy
    available in maritime installations to supply the demand for electrical energy needed by a
    vessel during the period in which it is berthed, which can last from a few hours to several
    days, replacing the use of the vessel's generator (main or auxiliary) for the electrical energy
    supplied by the port facility. In this way, by not using marine fuel in this process, tons of this
    fossil fuel, which is rich in sulfur concentrations, is avoided, reducing the emission of CO2,
    NOx, SOx and other polluting particles into the atmosphere. In addition to emissions,
    replacing the onboard generator also brings with it the advantage of reducing vibration and
    noise in the port region. This work takes a bottom-up approach using historical data from the
    last eleven years of port movement in Brazil to verify what the impact would have been if the
    use of Shore Power technology had been applied in that period, in addition to indicating the
    potential for financial gain with its use in the future in the main port facilities in the country.
    Environmental, regulatory and resource availability issues are also addressed in this context.
    In addition, it was developed, through a computer tool, entitled "Shore Power System
    Installation Feasibility Calculator through Monte Carlo Simulation", registered with the
    National Institute of Industrial Property - INPI (Patents, Computer Programs and
    Topographies Directorate). of Integrated Circuits), with the aim of reducing, or at least
    realizing in advance, the impact of the instability of the financial markets, making it possible
    to plan the business or project using the Shore Power concept. seeking to indicate potential
    gains from its use, even if its use is not mandatory in the country, but which is shown as a
    green alternative in the search for the best and most conscious environmental practices, in
    addition to the creation of investment and technology in the country, both for the sector
    electricity and for the port.

14
  • MAX OLINTO MOREIRA
  • PHOTOVOLTAIC GENERATION FORECASTING THROUGH COMPUTATIONAL METHODS PARAMETERIZED BY DESIGN OF EXPERIMENTS

  • Leader : PEDRO PAULO BALESTRASSI
  • MEMBRES DE LA BANQUE :
  • TAKAAKI OHISHI
  • ANTONIO CARLOS ZAMBRONI DE SOUZA
  • BENEDITO DONIZETI BONATTO
  • PAULO FERNANDO RIBEIRO
  • PEDRO PAULO BALESTRASSI
  • WESLEY VIEIRA DA SILVA
  • Data: 12 juil. 2022


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  • In recent years, renewable and sustainable energy sources have attracted the attention of various investors and stakeholders, such as energy sector players and consumers. Electric power systems have experienced the rapid insertion of distributed renewable generating sources and, as a result, face planning and operational challenges as new connections are made to the grid. It is very difficult to observe and anticipate the required levels of photovoltaic generation, which are tasks considered inherent to a quick insertion into the electrical grid. This distributed/renewable generation must be integrated in a coordinated way, so that there is no negative impact on the electrical performance of the grid, increasing the complexity of energy management. In this work, a multivariate strategy, based on design of experiments (DOE), is addressed for the prediction of photovoltaic generation using a new approach for parameterization and combination of a set of artificial neural networks (ANN). Two main questions will be explored: how to select the ANNs and how to combine them in the forecast by sets (ensemble). As a complement to this methodology, the reduction of dimensionality of climate data through Principal Component Analysis (PCA) is also presented. The design of experiments (DOE) approach is applied to the PV generation time series factors and to the ANN factors. Then, a cluster analysis is performed to select the networks that obtained the best results. From this point, a mixture analysis (MDE) is used to determine the ideal weights for the formation of the ensemble. The methodology is detailed throughout the work and, based on the combination of forecasts, the photovoltaic generation was estimated for a set of specific panels, located in the south of the State of Minas Gerais. Therefore, a more comprehensive study, which considered a dataset of seventeen generation plants, with seasonal characteristics, was also examined. The versatility of the proposed method allowed changing the number of factors to be used in the experimental arrangement, in the forecasting model and in the desired forecasting horizon and, consequently, improving the determination of the forecast for the studied scenarios.

15
  • ÉDISON MASSAO MOTOKI
  • Interruption Cost in Industrial Process due Voltage Sag

  • Leader : JOSE MARIA DE CARVALHO FILHO
  • MEMBRES DE LA BANQUE :
  • PAULO HENRIQUE OLIVEIRA REZENDE
  • AURELIO LUIZ MAGALHAES COELHO
  • FERNANDO NUNES BELCHIOR
  • JOSE MARIA DE CARVALHO FILHO
  • PAULO MARCIO DA SILVEIRA
  • THIAGO CLE DE OLIVEIRA
  • Data: 25 juil. 2022


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  • With the advent of electro-electronic technology, the industries have invested in systems and equipment in order to increase productivity and quality of their products. At the same time, researchers indicate that, linked to their use the equipment and systems bring great sensitivity in their operation which impacts on production continuity, generating significant economic losses for companies, especially those in the industrial sector.
    Short-term voltage variations, mainly when there are momentary voltage sags bring very serious consequences for consumer units, especially for those industrial units with sensitive loads.
    It is, therefore, essential that studies on costs of interruption in industrial processes due to voltage sags begin to be prioritized by electric energy concessionaires and researchers, so that the results start contributing to the improvement of the image and relationship between the concessionaire and its customers, as well as for the academic society, technicians and agents of the electric sector.
    The objective of this work is to present the results of a methodology to obtain the costs of industrial stoppages due to momentary voltage sags. This is a direct survey, through a questionnaire with the consumer units, composed of several industries supplied by medium voltage networks granted by EDP – Energias de Portugal.
    Initially, 70 industries were selected, of which 60 were chosen by EDP itself. Of this total, 33 agreed to participate in the research. They are classified into 12 different types of activities, thus allowing an assessment of costs per event and per installed demand.
    The research was supported by an ANEEL R&D project by EDP, covering industries from the southeast region (São Paulo and Espírito Santo) and its results were very coherent compared to the few estimations that may be found in the literature, although these are related to shutdowns in general.
    Crowning the work, the costs found were used in order to have a broader evaluation (annual costs) from existing measurements at EDP, considering shutdowns that happened in 61 substations’ busbars in the states of ES and SP.
    Finally, it is worth mentioning that this research brought a relevant technical contribution to the Brazilian electricity sector, helping to fill gaps in the national literature when this subject tries to be addressed.

16
  • JOÃO MARCONDES CORRÊA GUIMARÃES
  • DEVELOPMENT OF A PARTIAL DISCHARGE SENSOR AND A METHODOLOGY FOR SENSORS INVESTMENT PRIORITIZATION

  • Leader : EDSON DA COSTA BORTONI
  • MEMBRES DE LA BANQUE :
  • EDSON DA COSTA BORTONI
  • JAMIL HADDAD
  • LEONARDO MESQUITA
  • LUIZ OCTAVIO MATTOS DOS REIS
  • ROBERTO AKIRA YAMACHITA
  • RONALDO ROSSI
  • Data: 26 juil. 2022


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  • Power transformers are directly related to the electrical system reliability and power companies are pressured to improve the quality of service provided. In this scenario, real-time monitoring presents a strategic advantage by providing alarms and information for diagnostic algorithms and asset condition. However, the associated cost still is a limiting factor in the dissemination of monitoring systems, especially for lower value transformers such as those in distribution substations. This work contributes to the real-time monitoring of transformers on two aspects. The first being the development of a partial discharge sensor based on the IEC 60270 electrical method, motivated by the fact that the transformer life is directly associated with the condition of its insulation system and, according to the literature, approximately 36% of transformer failures are of dielectric origin, and the partial discharge measurement presents as one method for evaluating the condition of this system, since they are indicative of incipient defects and present an accumulative behavior. The developed sensor was submitted to laboratory tests to guarantee the operational safety of its application in 06 transformers of 145 kV for online monitoring and, also, it was used to measure partial discharges in a transformer with formation of combustible gases. The second contribution is a methodology for prioritizing investment in monitoring systems for distribution power transformers in the Brazilian regulated energy market, considering that for the monitoring of all subsystems of a transformer, other sensors are needed together with the partial discharge sensor developed in this work. This methodology considers the technical, technological, and regulatory dimensions and was implemented for a population of 848 transformers.

17
  • GUILHERME MARTINEZ FIGUEIREDO FERRAZ
  • Premature Failure Detection in Power Transformers Through Analysis of Partial Discharge Signals

  • Leader : ESTACIO TAVARES WANDERLEY NETO
  • MEMBRES DE LA BANQUE :
  • JOSÉ PISSOLATO FILHO
  • ESTACIO TAVARES WANDERLEY NETO
  • JOSE CARLOS GRILO RODRIGUES
  • JOSE FELICIANO ADAMI
  • MAURICIO CAMPOS PASSARO
  • Data: 23 août 2022


  • Afficher le Résumé
  • This thesis presents an investigation aimed at detecting premature failures in power transformers. To achieve this objective, it was necessary to develop a partial discharge detection system by analyzing signals collected directly from the capacitive bushing terminals and from the earth leakage current. In this way, an innovative system of acquisition, data processing and monitoring of partial discharges was proposed by mitigating fragile points from the analysis of the state of the art of partial discharge measurement systems used by the main existing manufacturers in the world. Then, the challenges and main technological barriers for the design and manufacture of field sensors for this activity were addressed. Throughout the text, the technical choices adopted for the development of a monitoring system in the field and the computational challenges encountered during the process of developing an analysis computer program, agile and robust to failures, are described. Next, the digital filtering methods used for the task of switching between the time domain and the frequency domain are presented. Therefore, the proposed system aims to detect the formation of partial discharges in initial situations with data analysis techniques and capture by the capacitive coupler, process such information and define the correlation with established techniques of analysis of the formation of combustible gases detected in the insulating oil. The difficulties encountered during the investigation and the computational costs that this analysis action requires are also described. Finally, through case studies, we present some examples of fault detection in field-installed transformers, current transformers and lightning rods, the advantages of the fault detection system proposed in this research and its application to different devices that share the degradation through the formation of partial discharges.

18
  • GUILHERME SOUTO CHAGAS
  • Enhanced Power Flow Methods in Complex Plane for VSC-MTDC Hybrid AC/DC Transmission Grids.

  • Leader : ROBSON CELSO PIRES
  • MEMBRES DE LA BANQUE :
  • MAURÍCIO AREDES
  • BENEDITO DONIZETI BONATTO
  • CARLOS ALBERTO DE CASTRO JUNIO
  • JOÃO ALBERTO PASSOS FILHO
  • ROBSON CELSO PIRES
  • ZULMAR SOARES MACHADO JUNIOR
  • Data: 24 août 2022


  • Afficher le Résumé
  • The power flow problem is composed of phasor variables and quantities and thus can be naturally formulated in the complex domain; however, their applications are commonly developed in the real domain. The solution via the Newton-Raphson method, for example, would be restricted in the real domain once the Taylor series expansion in terms of complex variables alone does not exist. Thanks to the Wirtinger calculus, a Newton-Raphson method based on Taylor series expansions of nonlinear functions of complex variables and their complex conjugates becomes possible. As new technologies are implemented in power systems, such as the incorporation of FACTS devices, the development of power flow applications becomes increasingly intricate, and maintaining their formulations in the real domain is preceded by an arduous algebra task. To overcome this difficulty, a series of power flow solution methods are proposed in this work, specified to solve multi-terminal AC/DC hybrid systems, being formulated in the complex plane without any loss of precision. Both sequential and unified approaches for solving hybrid AC/DC power flow are derived in the complex plane. In order to improve the performance of the algorithms, an exact second-order power flow algorithm in the complex domain is also proposed. Such power flow models in the complex plane are naturally developed in Cartesian coordinates; therefore, most constraint equations can be written as quadratic functions. Consequently, the Taylor series expansion stops at its second order and the exact non-linearity of complex quadratic power flow equations is maintained. Minor changes in the code structure are required to transform the Newton-Raphson method into the exact power flow approach in the complex plane. The new algorithm exhibits either a superior behavior in fully AC or hybrid AC/DC networks. In order to show the validity of its formulations, the proposed algorithms are implemented in Matlab for well-established case studies of the IEEE-14, -30, -57 and -118 bus, a modified version of the IEEE Two Area RTS-96, and the Brazilian Southern-equivalent of 1916-buses, termed as SIN-1916. The features and advantages of the proposed algorithms are illustrated through the test systems interconnected across a DC network prone to several scenarios, e.g., topology, voltage control, and interchanging of active power.

19
  • FÁBIO JÚNIOR ALVES
  • A Protocol to Guide the Development and Validation of ABA-Based Technologies for the Treatment of Autism

  • Leader : GUILHERME SOUSA BASTOS
  • MEMBRES DE LA BANQUE :
  • CHRISTIANA GONÇALVES MEIRA DE ALMEIDA
  • LYRENE FERNADES DA SILVA
  • ADLER DINIZ DE SOUZA
  • BENEDITO DONIZETI BONATTO
  • GUILHERME SOUSA BASTOS
  • RICARDO ZORZETTO NICOLIELLO VENCIO
  • Data: 8 déc. 2022


  • Afficher le Résumé
  • Autism Spectrum Disorder (ASD) is a neurodevelopmental condition that affects about 1-2% of the global population and leads to long-term challenges in the daily social lives of individuals with the disability. Based mainly on behavioral symptoms, the ASD is usually diagnosed after the second year of life. Beyond that, research indicates that the prevalence rates of this disorder have increased during the last three decades. Early interventions based on Applied Behavior Analysis (ABA) have contributed to good results in treatments, demonstrating significant improvements in language, cognitive ability and social skills for many individuals diagnosed with ASD. Besides ABA, Assistive Technologies (ATs) such as games, robots, among others, contribute positively to the development and learning process compared to other instructional methods. Then, associating ABA practices with the use of technology can contribute to controllable intervention, structured, adaptable, stimulating and increasingly effective processes. However, it is observed that ATs designed based on ABA principles for ASD treatment do not meet the criteria proposed by this science. Thus, this paper's main objective was to propose ALVINA: A Protocol to Guide the Development and Validation of ABA-Based Technologies for the Treatment of Autism. As a way of expanding reflections and reinforcing the importance and benefits of ALVINA, an evaluation was carried out, which took place through the application of questionnaires, in which computer professionals and Behavior Analysts participated. As a result of this assessment, these professionals highlighted the relevance of ALVINA information, considering it capable of involving important and essential points in the understanding process of how to validate and design ABA-based ATs for the ASD treatment, besides intelligibly meeting the criteria for the fundamental principles of this science. All this demonstrates the professionals involved in the ALVINA assessment have recognized the importance and need of a protocol for the development and validation of a proposed AT to be used during the intervention process. Furthermore, as a way of demonstrating the applicability of ALVINA, it was used to validate the SEIA: Teaching System Based on Artificial Intelligence and ABA and TEO: An Interactive Game Suite To Support The Treatment Of Children With Autism. Through this validation, the Behavior Analysts analyzed the weaknesses and strengths of SEIA and TEO. The guidelines described by ALVINA were also used for the development of a prototype called AUTISMALG: Application to Assist in Teaching Identification and Counting Number for Children with Autism Spectrum Disorder. This prototype aimed to identify and understand the application of the recommendations of each guideline proposed by ALVINA in the development of an AT. Finally, it is expected that the guidelines proposed by this protocol be efficient in the validation and development of ATs, aiming to ensure the correct execution of ABA practices during the intervention process, thus providing improvements for the treatment of individuals with ASD.

20
  • RICARDO FRANCISCO ALONSO CARDOZO
  • Reconfiguration of active systems with optimal allocation of batteries

  • Leader : ANTONIO CARLOS ZAMBRONI DE SOUZA
  • MEMBRES DE LA BANQUE :
  • ANTONIO CARLOS ZAMBRONI DE SOUZA
  • PEDRO PAULO BALESTRASSI
  • ELIANE VALENCA NASCIMENTO DE LORENCI
  • GILNEY DAMM
  • GLAUCO NERY TARANTO
  • JULIO CESAR STACCHINI DE SOUZA
  • Data: 9 déc. 2022


  • Afficher le Résumé
  • Resilience of electrical power systems is a paradigm that has been studied in order to provide continuity to the electrical energy service during the interruption of the main source.
    This leads to the need to use the existing resources in the microgrid in an intelligent way in order to, first, serve as many users as possible and second, for the longest possible time. Then the question becomes an energy optimization problem.
    In this context, the service of important loads such as hospitals, government, transport, public lighting, and telecommunications has to be considered as a priority. In this work, the connection of priority loads is made before the other loads.
    The restoration of loads can be done from a centralized or in a decentralized way. In this work, the reestablishment of loads will be analyzed in a centralized way, from a supervisory organism or Distribution Management System, ADMS for its acronyms in English (Advantage Distribution Management System).
    The methodology includes the remote connection and disconnection of loads and switches, as well as the allocation of battery-DC/AC inverter set mounted on trucks (MTBESS) at strategic points intelligently chosen in order to restore the largest amount of priority load possible first and then the other loads.
    In this sense, MTBESS are a very important asset to achieve this multipurpose.
    This work proposes a strategy for the use of MTBESS in charging and discharging regimes with the idea of supporting the other generation sources to meet the demands during the interruption time.
    Distribution systems are very dynamic, scenarios vary depending on distributed generation availability, time of day, typical day, etc. So the allocation of battery trucks, the state of switches (open or closed) and connected loads may vary according to these scenarios.

21
  • JOSÉ HUGO DE CARVALHO SOUZA
  • AUTOMATIC SYSTEM FOR CONTROL OF OVERFLOW REACTIVE IN OBSOLETE SUBSTATIONS BY COLOR PETRI NETWORK MODELING (RDP)

  • Leader : BENEDITO ISAIAS LIMA FULY
  • MEMBRES DE LA BANQUE :
  • MARA LUCIA MARTINS LOPES
  • ANNA DIVA PLASENCIA LOTUFO
  • BENEDITO ISAIAS LIMA FULY
  • CAMILA PAES SALOMON
  • MAURICIO CAMPOS PASSARO
  • Data: 9 déc. 2022


  • Afficher le Résumé
  • This work presents a new approach for the treatment of surplus reactive energy in industrial plants that has capacitor banks in the substation in obsolescence and limited to high numbers of maneuvers. The purpose of this thesis is to perform studies for the purpose of optimizing a discrete distributed system, from data sampled in the industrial sector, which contains problems in the substation power factor control system and consequently reactive energy surplus. In order to propose solutions to these problems, the modeling of the distributed system and the analysis of its properties were carried out through computer simulations. The tool that was used for a discrete system is the Colored Petri Net in CPN Tools. From the RdP model we obtain an autonomous decision-making system to connect and disconnect the capacitor banks according to the current of the furnaces, voltage, time of operation of the loads, discharging time of capacitor banks and time of day defined by resolution ANEEL 505, of November 26, 2001 aiming at reaching the power factor close to 1.00 and minimized numbers of high voltage circuit breaker operations. Implementing the model eliminates over reactive, fines, extends the lifetime of circuit breakers, capacitor banks, reduces the exposure of people in circuit breaker maneuvers and does not send noise on the transmission lines of the concessionaire. Completing the development and implementation of the new logical model of the power factor automation system, it was possible to achieve a 96% reduction in excess reactive energy, equivalent to 720,423 kWh per year in energy bills sent by the utility and a reduction of 90.4% number of circuit breaker operations compared to the traditional method of capacitor bank automation. The system also enabled a better structured understanding of the automation logic and assertiveness in the implementation of the system in the industrial controller, not generating interference in the process and rework.
    Key-

22
  • ANTONIO ALVES FERREIRA JÚNIOR
  • Modeling chromatic dispersion effects in radio-over-fiber transmission using microwave photonics

  • Leader : DANILO HENRIQUE SPADOTI
  • MEMBRES DE LA BANQUE :
  • LICINIUS DIMITRI SÁ DE ALCANTARA
  • CARLOS ALBERTO DE FRANCISCO
  • DANILO HENRIQUE SPADOTI
  • GABRIEL ANTONIO FANELLI DE SOUZA
  • JOSE ANTONIO JUSTINO RIBEIRO
  • MATEUS AUGUSTO FAUSTINO CHAIB JUNQUEIRA
  • Data: 15 déc. 2022


  • Afficher le Résumé
  • This work presents a proposal for closed analytical models for the analysis of radio-over-fiber (RoF) communication systems using microwave photonics. The influences of the optical fiber chromatic dispersion effects and the electro-optical modulators and photodetector nonlinearities on the received signal power were investigated. This contribution on the subject makes it possible to analyze the transmission of radiofrequency (RF) and microwave signals over long distances. By setting some parameters, it is possible to evaluate different applications such as generation and conversion of high frequency signals and photonic filters in the RF and microwave bands. Analytical solutions applicable to modern communication systems that employ 5G and 6G resources and that use analogue optical links were developed. For this, the Graf addition theorem was used for the Bessel functions of first kind and the Fourier transform, showing the spectra for the different parts of the system in the frequency domain. The results between the proposed large signal models and the approximate models were compared, highlighting the most significant differences. The models contemplate parameters of interest in the projects of these systems, including signals with large amplitudes. Among the most relevant values highlighted are the modulation RF signals frequencies, the modulation indices, the losses, the nonlinearities and the transmission coefficients of the electro-optical modulators. Also, the wavelength and power of the laser, the photodetector responsivity and nonlinearity, the attenuation, the length and the chromatic dispersion of the optical fiber, are evaluated.
    To evaluate the proposed analytical models, the radio over fiber links with phase and intensity modulations, both with direct detection, were investigated. The analog optical modulation formats such as phase, double sideband intensity, single sideband and suppressed carrier, were adopted. External electro-optical modulators such as phase and Mach-Zehnder intensity with dual-drive and with single drive, were used. In addition, applications are presented in microwave frequency generation and in OOK digital information transmission, both using the proposed models. With a single model, it is pos-sible to determine the link responses with different analog optical modulations that use phase or amplitude modulators and with direct detection.

23
  • ALENCAR FRANCO DE SOUZA
  • PROPOSAL FOR A NEW TOPOLOGY OF CA-AC CONVERTER TO SWITCHED CAPACITOR

  • Leader : ENIO ROBERTO RIBEIRO
  • MEMBRES DE LA BANQUE :
  • EDILSON MINEIRO SÁ JUNIOR
  • ROMERO LEANDRO ANDERSEN
  • ENIO ROBERTO RIBEIRO
  • FERNANDO LESSA TOFOLI
  • GABRIEL ANTONIO FANELLI DE SOUZA
  • WANER WODSON APARECIDO GONCALVES SILVA
  • Data: 16 déc. 2022


  • Afficher le Résumé
  • The present work aims to present a new topology of direct AC-AC converter to switched capacitor. This topology employs only semiconductor elements and capacitors, presenting itself as an alternative to low voltage autotransformers with reduced cost and size. This new structure can operate as a voltage step-up or step-down, with a gain of up to 3 or even 1/3, providing 3 different output voltage levels. Initially, the context of the use of autotransformers is shown for different applications. Direct AC-AC conversion structures are presented, from those that operate at low frequencies using controlled rectifiers, to those driven by PWM that employ high-speed switches. Among the latter, the switched capacitor converters stand out due to their constructive simplicity and performance. In this work, the proposed new topology and its operation steps are presented. Mathematical expressions are developed to calculate the elements that make up the converter. Finally, a circuit is designed, simulated and tested on the bench so that its calculations and operation can be validated. In bench tests, the converter showed an efficiency of 87.18% and regulation of 92.68% at full load. At the end of the text, a proposal for the continuity of the work for the conclusion of the thesis is presented.

2021
Thèses
1
  • KENJI NISHIDA
  • Pulsed Electromagnetic Field as a Mitigation Strategy for Limnoperna fortunei Infestation in Hydroelectric Power Plants

  • Leader : TALES CLEBER PIMENTA
  • MEMBRES DE LA BANQUE :
  • ALEXANDRE BARATELLA LUGLI
  • CARLOS BARREIRA MARTINEZ
  • ROBSON LUIZ MORENO
  • TALES CLEBER PIMENTA
  • Data: 26 févr. 2021


  • Afficher le Résumé
  • This work aims to evaluate the efficiency of the application of the pulsed electromagnetic field in the assisted precipitation of calcium carbonate, to decrease the supply of dissolved calcium in the water, as an innovative strategy to prevent and control the infestation of the golden mussel (Limnoperna fortunei) in hydroelectric plants. However, pulsed electromagnetic field applications can also be found to prevent scale build-up in pipes and heat exchangers, for reducing of hard water.
    With an analysis of the actual river water parameters, it can be seen that electrical conductivity can be used as an indirect approach to monitor the level of calcium carbonate concentration, and keep the amount of dissolved calcium ions low to minimize environmental and economic problems caused by the golden mussel.
    To obtain the assisted precipitation of the calcium carbonate resulting from the magnetic force acting on the calcium, bicarbonate and carbonates ions dissolved in the water, a pulsed electromagnetic field was applied at 90 degrees of the direction of water displacement inside a plastic pipe, combined with a sudden increase in travel speed.
    The correct choice of procedures and the way to conduct the tests to validate the concept of this work, is essential to ensure that it does not result in low repeatability and reproducibility in the studies carried out.
    Keywords: electromagnetic field, hard water, Limnoperna fortunei, calcium carbonate.

2
  • FERNANDO LUIS LEAL JUNG
  • Industrial Equipment Sensitivity to Voltage Sags

  • Leader : JOSE MARIA DE CARVALHO FILHO
  • MEMBRES DE LA BANQUE :
  • AURELIO LUIZ MAGALHAES COELHO
  • FERNANDO NUNES BELCHIOR
  • FREDERICO OLIVEIRA PASSOS
  • JOSE MARIA DE CARVALHO FILHO
  • Data: 12 mars 2021


  • Afficher le Résumé
  • Voltage sags are deviations in the rms voltage that may lead to electrical equipment malfunction. Characterized mainly by its magnitude and duration, these events display many other characteristics that may affect electrical equipment behaviour. Equipment sensitivity curve characterization varies accordingly to equipment type, and is a main factor for analysing industrial process interruption. From the curve characterization methods available in literature, for this work, it is used the Left-Right method proposed on IEEE 1668-2017, in an automated form, using hardware-in-the-loop capability of RTDS. The devices tested are the most used in industrial plants in low voltage (less than 1000V): a.c. and c.c. electromagnetic contactor, switched-mode power supplies and PLC. The equipment are tested individually, but also as a group, simulating an industrial workbench. The sensitivity curves are obtained by repeating the same event, in order to evaluate the occurrence of a fuzzy zone. The results are analyzed and some considerations are raised about the procedure adopted and equipment sensitivity as well.

3
  • Ricardo Barbosa de Almeida Campos
  • Intelligent System for Control and Monitoring of Power Grid for Thermoelectric Plants Based on Multicriteria Decision Support Method

  • Leader : LUIZ EDUARDO BORGES DA SILVA
  • MEMBRES DE LA BANQUE :
  • GERMANO LAMBERT TORRES
  • GISCARD FRANCIMEIRE CINTRA VELOSO
  • LUIZ EDUARDO BORGES DA SILVA
  • RONDINELI RODRIGUES PEREIRA
  • Data: 26 avr. 2021


  • Afficher le Résumé
  • To keep the power generators in a good state of operation might be a daunting task, because it will probably involve a considerable number of generators and each one of them having a great number of variables to be monitored and processed. Besides that, can be added the fact that some thermo electrical power plants operate in a regime in which they have to dispatch power in a non-scheduled routine, when demanded by ONS. The class and the type of the power generator units are important, because, it’s expected that the synchronization time of the first unit and the operating time at full power should be no more than 30 minutes. Which is relatively low, when there are a great number of generators. Following these thoughts, it is imperative having a smart tool that is capable of showing the actual state of each motor, furthermore will assist it in having a more efficient start and power generation.
    It was presented in this dissertation the development of a smart control and monitoring system for thermoelectric power plants, that also includes the elaboration of a modification in the Analytic Hierarchic Process that it will the process faster. This tool will be capable of investigating wide array of variables that are being originated from the generators. Moreover, will provide alerts, create a database with all the most relevant information, implement a supervisory capable of showing all the data needed by who is operating the machine and for last, develop a software that it analyzes all of the collected data and rank all the generators.
    The scope of this work will approach the selection of the sensor. It will compose the data collection part of the system, the part needed to assemble a robust data transmission infrastructure, study and select mathematical tools. Then, these all structure will allow the ranking of all the generators and give the possibility to the operator, which can modify the evaluation profiles and to validate the whole system.

4
  • BRUNO GOMES RODRIGUES
  • Protection Optimization in Distribution Networks with Distributed Generation

  • Leader : JOSE MARIA DE CARVALHO FILHO
  • MEMBRES DE LA BANQUE :
  • AURELIO LUIZ MAGALHAES COELHO
  • FERNANDO NUNES BELCHIOR
  • JOSE MARIA DE CARVALHO FILHO
  • THIAGO CLE DE OLIVEIRA
  • Data: 28 mai 2021


  • Afficher le Résumé
  • The Brazilian distribution systems have experimented a profound change since the conditions for inserting new sources of electric power in these systems called mini and micro distributed generation were standardized. These sources, composed of different types of technologies such as Wind Power, Photovoltaic, Hydroelectric and Thermoelectric Power Plants have grown at a rapid pace from 6 connections in 2012 to more than 300,000 in 2020.
    Despite the benefits of using distributed generation (DG) for the electrical system, with the reduction of electrical losses in distribution, and for customers, with the possibility of using credits with surpluses generated, the use of these different generation technologies unleashes discussions about its impacts on the system.
    Among the impacts, we can emphasize those related to the protection systems in the distribution lines that directly affect the reliability of the energy supply to customers, and can even turn into fines for the utilities.
    Regarding the classic methodologies for protecting distribution lines, consisting of selective and coordinated protection philosophies, which take into account their predominance of radial configuration, with the presence of a single source, the presence of the distributed generation changes the dynamics events in these systems and thereby make current protection methodologies obsolete, requiring the application of dynamic and more adaptable methodologies.
    Considering the above, the present work proposes a study of the impacts of distributed generation for the classical protection of electrical power distribution systems and the proposal of a protection methodology aiming at the optimization and correct performance of the protection system. The proposed methodology aims to obtain optimized protection settings that attend to the different operating scenarios of the system with DG, maintaining selectivity and coordination among equipment and allowing the increase of system reliability.
    This evaluation will be done through a case study, using specific software for distribution protection studies, where the real characteristics of a feeder from an important Brazilian Utility that has a connection with distributed generation through hydroelectric power were modeled.
    The developed study evidences the significant influence of DG on the distribution systems protection, with more significant impacts in the coordinated protection philosophy. Furthermore, it is verified that the application of the protection settings determined through the proposed methodology reduces the impacts of the entry of DG in the system by approximately 49% when compared to the system with conventional protection methodology applied, maintaining the selective and coordinated philosophies in the different operating scenarios

5
  • LÚCIO JOSÉ DA MOTTA
  • Analysis of the immunity of computer power supplies under harmonic distortions and voltage sags.

  • Leader : PAULO FERNANDO RIBEIRO
  • MEMBRES DE LA BANQUE :
  • ANTONIO CARLOS ZAMBRONI DE SOUZA
  • CARLOS AUGUSTO DUQUE
  • FERNANDO NUNES BELCHIOR
  • PAULO FERNANDO RIBEIRO
  • Data: 4 juin 2021


  • Afficher le Résumé
  • Power supplies for electronic devices are increasingly a significant segment of total load in power systems, many of which can impact on the power quality, as well as can suffer from the disturbances present in it. Thus, many standards and recommendations been and are being developed to improve the compatibility between power systems and electronic devices, including standards that define limits for harmonic distortions and voltage sags.
    In this bias, this work shows some standards and recommendations pertinent of harmonic distortion, as well standards for immunity tests of devices submitted to voltage sags. In face this, experimental tests were realized with computers power supplies in controlled environment laboratory, where the basic parameters were recorded to permit detailed analysis of the power condition under different voltage excitations. Thus, in first step was checked the compatibility and immunity this equipment under test up high levels of voltage harmonic and posteriorly, this phenomena associated to voltage sag up 50% of the nominal voltage.
    Based on temperature, output voltage (DC), consumption current and function of power supplies, this work proves that this device can supported harmonic voltage distortion much larger than commons limits recommended (up 10 times more). Beside was certificated that the power supplies with power factor corrector (PFC) supported much more high voltage distortion levels, besides to have better performance and consumption less harmonic current than traditional design of power supplies. The results show that different waveform can affect the performance of load, principally when occur concomitantly the voltage sags, however any failure was observed for this case.
    From this work is feasible to think that the regulations, principally those concern the harmonic distortion, need more frequently studies and updates, considering the existence of many models of devices, in addition the better design in it. Also stay clear the necessity more investigation with different kinds and topology of power supplies for the comprehensive evaluation their performance, besides to evaluate the compatibility with the standards and recommendations, considering that the present harmonic distortion limits can be considerate much severe as to the evaluated objects.

6
  • PATRÍCIA FERREIRA SILVA
  • Analysis of Models and Feasibility for Insertion of Generation Systems Photovoltaics in Public Universities Brazilians Aiming at Sustainability Energetics

  • Leader : BENEDITO DONIZETI BONATTO
  • MEMBRES DE LA BANQUE :
  • ANTONIO CARLOS ZAMBRONI DE SOUZA
  • BENEDITO DONIZETI BONATTO
  • FERNANDO NUNES BELCHIOR
  • RAFAEL DE CARVALHO MIRANDA
  • VICTOR EDUARDO DE MELLO VALERIO
  • Data: 2 juil. 2021


  • Afficher le Résumé
  • Although Brazilian Universities and Federal Institutes have been awarded some
    decentralizations of the public power for the installation of photovoltaic systems
    to mitigate electricity costs, a greater economic incentive from the government is
    still needed, so that they can use better the practices of the sciences and
    technologies that they develop in a way that they become energetically
    sustainable. The present work had as general objective to organize a business
    model in a stochastic way to foment public investment in photovoltaic systems in
    the context of Distributed Generation - GD in a sample of Federal Institutes of
    Higher Education - IFES, being analyzed 9 universities and 26 campuses. The
    following specific research objectives were investigated by evaluating the
    feasibility of generation in the federal universities' own load, assessing the
    feasibility of remote self-consumption of federal universities, analyzing the risk
    and uncertainty in each case and finally organizing a framework of investment
    decision-making according to the concession area of each federal university, in
    order to optimize its energy issue and establish a decision-making method. The
    analysis was performed using Monte Carlo simulation. As they are alternatives
    that compete with each other and have the same time horizon, it can be said that
    they are mutually exclusive alternatives and, therefore, only one will be executed
    (chosen). And as indicators for analysis, Net Present Value, Annualized Value,
    Return on Investment and discounted payback were used. With the results
    obtained, it was concluded that the installation of a photovoltaic system in both
    scenarios is feasible, however, as only one project should be chosen, the
    installation of a photovoltaic system in each university campus is much more
    attractive, as the studies showed.

7
  • ANDRESA APARECIDA LEMES GOMES
  • Study of the Energy Potential of Anaerobic Digestion of the Organic Fraction of Urban Solid Waste in the City of Extrema

  • Leader : ESTACIO TAVARES WANDERLEY NETO
  • MEMBRES DE LA BANQUE :
  • ESTACIO TAVARES WANDERLEY NETO
  • MARIA CLAUDIA COSTA DE OLIVEIRA BOTAN
  • REGINA MAMBELI BARROS
  • ROBERTO AKIRA YAMACHITA
  • Data: 5 juil. 2021


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  • The management of urban solid waste is currently one of society's greatest problems, because when they do not receive an adequate final disposal, they cause major health, social and environmental problems. Therefore, sanitary landfills are the most suitable means for the disposal of waste. In landfills, the anaerobic digestion of urban solid waste that occurs naturally, has emerged as an interesting way to treat these wastes, since the biogas produced during the process can be used to produce electricity. During the anaerobic digestion process there is the production of methane (CH4) which, during burning for energy production, transforms this methane into carbon gas (CO2), presenting an advantage for the reduction of greenhouse gases. Therefore, this work presents a study of the technical and economic potential of energy generation for the use of biogas from the landfill in the city of Extrema MG through a routine developed in the Scilab, Microsoft Excel and LandGEM programs. The results indicated that there is great potential for energy generation in the landfill, in addition to being an economically viable enterprise. Two scenarios of sale were presented, for sale in energy auction and for sale in distributed generation, the first scenario proved to be unfeasible with a loss of R$ 48.81 per MWh and the second scenario showed that the project is a good investment, presenting a profit of R$ 74.29 MWh.

8
  • JEAN RODRIGO DOS SANTOS
  • Analysis of the Impact of Transients on Networks of Distribution on Photovoltaic Systems.

  • Leader : ESTACIO TAVARES WANDERLEY NETO
  • MEMBRES DE LA BANQUE :
  • BENEDITO DONIZETI BONATTO
  • ESTACIO TAVARES WANDERLEY NETO
  • GUSTAVO PAIVA LOPES
  • JOSE FELICIANO ADAMI
  • Data: 8 juil. 2021


  • Afficher le Résumé
  • Distributed generation has grown every year as a way of diversifying the energy matrix,
    with photovoltaic energy being one of the most promising as it is a clean energy that is
    easy to use. Small and medium-sized photovoltaic plants have been built both in urban
    centers for direct use at the generation site, as well as in more distant regions, in which
    the energy produced is transferred to the existing electricity grid of local concessionaires.
    The growth of this type of generation plant, interconnected to existing grids, requires
    studies to assess disturbances that may affect the grid and, consequently, the photovoltaic
    systems. In this aspect, this work aims to implement a complete photovoltaic generation
    system model and an electrical distribution network in the ATP R software, through its ATPDRAW graphical interface, in order to analyze the behavior of these systems, against
    transient disturbances that affect its operation in the electrical network. The software used
    has great advantage in the implementation and simulation of electrical events, through
    existing components, or the creation of new ones through mathematical equations. With
    that, through mathematical models, were implemented through equations, components
    that represent the real characteristics, for the operation of the system as a whole. The
    application of certain elements for the protection of photovoltaic systems from electrical
    disturbances caused in the distribution network was thus observed and validated.

9
  • RENAN DE FÁVERI
  • Thermal Transformer Modeling - Multiple Linear Regression Method for Predicting Variables

  • Leader : ESTACIO TAVARES WANDERLEY NETO
  • MEMBRES DE LA BANQUE :
  • ALESSANDRA FREITAS PICANÇO
  • CREDSON DE SALLES
  • ESTACIO TAVARES WANDERLEY NETO
  • RICARDO ELIAS CAETANO
  • Data: 12 juil. 2021


  • Afficher le Résumé
  • For the proper operation of transformers, the temperature control is fundamental, since temperature is the main limiting factor for the load of the transformer, directly affecting its lifespan. In this context, this work aims to study the thermic behaviour of transformers using data acquisition, using the database generated by the supervisory system and climate data collected by a meteorological station installed in the substation area, using linear regression analysis tool, and searching for correlations between the temperature of the transformer and other operational parameters. The correlation analysis aims to verify the statistical inferences of the linear association parameters such as the multiple correlation coefficient, which measures the “strength”” or “degree” of linear relation between a variable and a set of other variables. This way, it is possible to generate a tendency for the temperature rise curve of the transformer and parameters such as its load. Therefore, an application to predict the thermal variables of a three-phase 230/138/13.8, 150 MVA transformer using oil, windings and room temperatures and active power collected in intervals of 5 minutes was developed. After treatment and tabulation of the collected information, various correlation situations were studied in each analysis, were one parameter was chosen as main or dependent. By the end of the simulations, the r-square value for each scenario was found, and consequentially the equations that represent the dependent variable. By recalculating the dependent variable through these equations, it was noticed that the best equation for the prediction of load and temperature situations was the one that used more independent variables, being the one closest to the value measured by the SAGE supervisory. Ultimately, through system modelling, this tool can be incorporated to the SCADA system in the operation centre of the power distribution companies to assist on equipment temperature prediction analysis on critical situations, or as an assist tool for data refreshment in case of a failure on the acquisition equipment.

10
  • LEONARDO RIBEIRO GONÇALVES
  • Development of Low Cost Spectrum Qualifier for new IoT Technologies

  • Leader : TALES CLEBER PIMENTA
  • MEMBRES DE LA BANQUE :
  • CARLOS NAZARETH MOTTA MARINS
  • DANILO HENRIQUE SPADOTI
  • GABRIEL ANTONIO FANELLI DE SOUZA
  • TALES CLEBER PIMENTA
  • Data: 16 juil. 2021


  • Afficher le Résumé
  • With the evolution of radio technologies during the last decades, the companies are replacing equipment with individual components with particular functions by systems where most signals are treated digitally through digital signal processing techniques. With this, engineers can develop many applications at the software level, enabling new analyses to exists. With the growth of the internet of things, companies are deploying new solutions around the world. Most of these solutions are wireless applications that use the unlicensed frequency spectrum band, which increases the density of wireless devices in a location. In environments with numerous wireless equipment transmitting simultaneously, it is essential to detect how busy the frequency spectrum is before deploying a new solution. A spectrum analyzer can analyze this, but the cost of acquiring suitable equipment can be very high. Besides that, these devices only allow users to analyze the frequency spectrum, not the technology itself, packet loss, data rate, and coverage, without purchasing expensive software licenses. This thesis presents the development of a Software Defined Radio(SDR) application capable of indicating the best channels on frequency spectrum to be used by wireless technologies.

11
  • LANA GABRIELLA SOUZA LOPES
  • Proposal for a discrete speed control system for an induction generator operating in parallel with a synchronous generator to avoid system frequency increase in the case of reduced load supply

  • Leader : ANGELO JOSE JUNQUEIRA REZEK
  • MEMBRES DE LA BANQUE :
  • ADRIANA APARECIDA DOS SANTOS IZIDORO
  • ANGELO JOSE JUNQUEIRA REZEK
  • JOSE CARLOS GRILO RODRIGUES
  • Data: 20 juil. 2021


  • Afficher le Résumé
  • In the case of parallel operation of a synchronous generator with an asynchronous induction generator, the synchronous generator can be motorized, when the active power supplied by the induction generator is greater than the power absorbed by the load fed by the two generators in parallel. In this case, there is an alternative in order to avoid this occurrence, which is the decrease of the speed of the asynchronous generator, for the purpose of decreasing its active power supplying. This dissertation describes a proposal of a discrete speed control system for the induction machine that contemplates this solution. A data acquisition electronic board and a microcomputer are used to enable the implementation of the referred proposed speed control system, in which harmonics are not generated, because there are no static converters using semiconductors connected at the terminals of the machines, a favorable aspect related to the quality of the electrical energy.

12
  • PAULO VITOR PECLAT DE OLIVEIRA TAVARES
  • Analysis of failure in distribution transformers during lightning impulse test

  • Leader : ESTACIO TAVARES WANDERLEY NETO
  • MEMBRES DE LA BANQUE :
  • CREDSON DE SALLES
  • ESTACIO TAVARES WANDERLEY NETO
  • TIAGO BANDEIRA MARCHESAN
  • Data: 26 juil. 2021


  • Afficher le Résumé
  • Due to its importance to the electric power system, transformers are subjected to normalized electric tests in order to guarantee its proper functioning in operation conditions, one of which is the lightning impulse test. Failure detection during the lightning impulse test can be accomplished through different methodologies and the analysis can be subjective and dependent of the evaluator’s experience. Thus, the purpose of this work is to revisit the main failure analysis techniques for transformers, then test and reevaluate them for distribution transformers, since most of the existent literature refers to high voltage transformers. The considered methods for this work were the failure detection in the time and frequency domains. For the time domain, the sensibility of different types of measurements, the relation between the direction of the measured current with the type of failure that occurs in the transformer, as well as the relation between the occurrence of high frequency signals and the presence of partial discharges in the transformer were analyzed. In the frequency domain, the capacity of the technique to compare different waveforms, including full and chopped lightning impulses, the relation between the attenuation or shift of the resonant pole of the response with the type of failure that occurred in the transformer were analyzed. The results verified the evaluated topics, with the exception of the failure characterization in the frequency domain, in which it was not possible to find the relation between the transfer function and the type of failure in the transformer. The coherence function was evaluated as a tool capable of determining the reliable frequency range for analysis in the frequency domain and, as a numerical indicator, reducing the subjectivity of fault identification.

13
  • ANTÔNIO CÉSAR COSTA FERREIRA ROSA
  • HV SHUNT REACTORS: an overall comparative analysis between dry-type air core and oil-immersed iron core technologies

  • Leader : ESTACIO TAVARES WANDERLEY NETO
  • MEMBRES DE LA BANQUE :
  • ESTACIO TAVARES WANDERLEY NETO
  • GUSTAVO PAIVA LOPES
  • MARCEL FERNANDO DA COSTA PARENTONI
  • TARSO VILELA FERREIRA
  • Data: 12 août 2021


  • Afficher le Résumé
  • Shunt reactors in high-voltage and extra high-voltage, have historically been
    manufactured using oil-immersed iron core technology, mainly due to issues related to
    the insulation of the reactor windings. However, with the improvement of the insulating
    films as well as on the manufacturing techniques, it has been possible the
    manufacturing of these equipment using dry-type air core technology, which has
    demonstrated to be efficient, environmentally friendly and, in many cases, with lower
    costs in short, medium and long-term basis. It is required therefore, the study of which
    are the changes when it is adopted this air core technology, which has been the more
    and more accepted on worldwide market. The main aspects regarding the application
    of these equipment are disclosed, stablishing a parallel between both technologies,
    with regards to the construction aspects, the viability of replacement (which are the
    cases at which they are or not indicated), the losses comparison, all the precautions
    and remarks in terms of magnetic field, the protection and the transients aspects
    (including a study case of two identical equipment in both technologies, with
    calculations and simulations of transient frequency and voltage, TRV and RRRV, as
    well as a percentage comparative analysis between the calculated and simulated
    results). These comparisons, aim to contribute with technical community and the global
    trend in adopting dry-type technology, highlighting the main differences and
    particularities to be considered when replacing traditional type.

14
  • LAERTY JOÃO DOS SANTOS DAMIÃO
  • Development of an Online Partial Discharges Monitoring System for Power Transformers

  • Leader : EDSON DA COSTA BORTONI
  • MEMBRES DE LA BANQUE :
  • EDSON DA COSTA BORTONI
  • ESTACIO TAVARES WANDERLEY NETO
  • FRANCISCO RICARDO ABRANTES COUY BARACHO
  • RONALDO ROSSI
  • Data: 17 août 2021


  • Afficher le Résumé
  • Serious failures in power transformers are usually driven by problems in the insulation structures, whether internal to the tank or in the bushings, and constitute one of the most critical occurrences of the power system. Thus, the evaluation of the insulation condition of a transformer is of great importance for the operational efficiency of the transmission and distribution of electrical energy. However, as insulation systems are complex, many challenges are seen in terms of measurement systems and modes of analysis of critical parameters such as partial discharges (PDs), which are recognized as a phenomenon that carries relevant information regarding the health of a high voltage equipment. In this context, this dissertation addresses the development of an online monitoring system for partial discharges for power transformers. The system applies the electrical method to detect the discharge pulses through capacitive coupling in condenser bushings and is integrated by a proprietary software for data processing and communication with supervisory systems through the DNP 3 protocol. The robustness of the developed system and the guarantee of integrity of the monitored equipment, as well as the ability to correlate data to track the condition of the asset, were verified by laboratory tests and real applications in substations. In the latter case, the results were explored to show how information from a PD can be interpreted in practical situations to analyze the conditions of the asset and assist in defining diagnoses.

15
  • HENRIQUE BORGES ZANINELLI
  • Improved Power Losses Calculation Model for Air Core Reactors

  • Leader : EDSON DA COSTA BORTONI
  • MEMBRES DE LA BANQUE :
  • MÁRIO FABIANO ALVES
  • EDSON DA COSTA BORTONI
  • ESTACIO TAVARES WANDERLEY NETO
  • Data: 10 sept. 2021


  • Afficher le Résumé
  • Proposition of an improvement for the calculation method of the winding power losses related to air core reactors by exploring the distribution of the magnetic field with the use of FEM and a 2-D equivalent geometry that makes this kind of analysis a lot faster than the usual complete simulation strand-by-strand 2-D FEM.

16
  • WANDERLEY DIAS XAVIER FILHO
  • Influence of the Static Var Compensator on the Power Flow-based Voltage Sags Locator

  • Leader : JOSE MARIA DE CARVALHO FILHO
  • MEMBRES DE LA BANQUE :
  • FERNANDO NUNES BELCHIOR
  • FREDERICO OLIVEIRA PASSOS
  • JOSE MARIA DE CARVALHO FILHO
  • MARCEL FERNANDO DA COSTA PARENTONI
  • Data: 29 sept. 2021


  • Afficher le Résumé
  • The current scenario of electrical power systems, the Electrical Power System Quality
    (EPSQ) earns more notoriety. Among the EPSQ problems, Voltage Sags cause
    considerable financial losses and locating Voltage Sags sources is one of the biggest
    challenges for electric power utilities. In this context, the thesis that addresses a locator
    which identifies the source side of the Voltage Sag font is approached. However, as
    large electrical systems, in addition to meshed ones, are more complex, this work is
    responsible for evaluating the performance of such a locator, through the modeling of
    a real electrical system considering the insertion of Static Var Compensators. In the
    study, an RTDS® (Real Time Digital Simulator) platform will be used both in the
    modeling of the system, as in the implementation of the locator and in the evaluation
    of its performance.

17
  • LEANDRO JUNIOR DE OLIVEIRA
  • Arc Flash in Industrial Systems: Calculation Methods and Mitigation Measures

  • Leader : JOSE MARIA DE CARVALHO FILHO
  • MEMBRES DE LA BANQUE :
  • JOSE MARIA DE CARVALHO FILHO
  • RONALDO ROSSI
  • THIAGO CLE DE OLIVEIRA
  • Data: 30 sept. 2021


  • Afficher le Résumé
  • In this work a study on the electric arc in industrial electrical systems will be presented, approaching the calculation methods according to the IEEE Std 1584 – 2002 and its revision IEEE Std 1584 – 2018 guides. The modifications introduced by the new version of the guide were presented, identifying the differences in the evaluation of the electric arc. An approach to arc flash mitigation measures will also be carried out. The development of the work was based on the comparative analysis of the electric arc calculation methods of the 2002 and 2018 versions, which were applied in a test case study. First, the test case will be evaluated by applying the calculation methods according to the 2002 and 2018 guides, being executed in dedicated “PTW” software. Subsequently, the test case will be evaluated again considering the AC decay of the short-circuit currents of generators and motors, being executed in scripts developed in "Matlab" and applying the equations from the 2002 and 2018 guides. The results of the approaches are compared, and The need and urgency of reviewing existing arc flash studies were then evaluated, as well as the influence when considering the AC decay of short-circuit currents in the incident energy calculations and in the definition of the garments.

18
  • JULLY ANDREA CALDERÓN COELLO
  • Analysis through Real-Time Simulation of the Electric System of an Off-shore Platform for Oil Production

  • Leader : PAULO MARCIO DA SILVEIRA
  • MEMBRES DE LA BANQUE :
  • CARLOS ALBERTO VILLEGAS GUERRERO
  • IVAN PAULO DE FARIA
  • JOSE CARLOS DE OLIVEIRA
  • PAULO MARCIO DA SILVEIRA
  • Data: 13 oct. 2021


  • Afficher le Résumé
  • The dynamic control of the power generation system is one of the most important elements
    in an offshore platform, since it is responsible for maintaining the electrical system
    stability both in steady-state and transient operation, thus avoiding the complete loss of
    power supply and, consequently, large economic losses. In this regard, the Real-Time Digital
    Simulator (RTDS) becomes an important tool, as it allows to simulate the generation
    system dynamic in real-time with the possibility of testing actual control and protection
    devices, through a hardware-in-the-loop scheme. Typically, off-line simulation studies of
    the generator dynamic control are carried out with limited information from manufacturers,
    which leads to the use of typical data for models and, therefore, the possibility
    of unreliable responses. However, to obtain a realistic behavior of the electrical system
    dynamic in the RTDS, an accurate representation of its models is necessary. In this sense,
    this work presents the detailed modeling of the excitation system and the speed regulador
    of the power generation system of an oil extraction platform in the RTDS. The validation
    of the mathematical models of the controllers developed in the RTDS was done through a
    comparative analysis between the results of field data and laboratory test. The electrical
    system of the platform was subject to several disturbances, once the real behavior of the
    generation system control was obtained.

19
  • LEONARDO DALCIN SILVA
  • FLOATING PHOTOVOLTAIC GENERATION COMBINED TO BIOGAS TO ELIMINATE MACROPHYTE FROM HYDROELECTRIC POWER PLANTS

  • Leader : TALES CLEBER PIMENTA
  • MEMBRES DE LA BANQUE :
  • ROBERTO PAULO DA SILVA PINTO JÚNIOR
  • CARLOS ROBERTO ROCHA
  • EDUARDO CRESTANA GUARDIA
  • TALES CLEBER PIMENTA
  • Data: 3 nov. 2021


  • Afficher le Résumé
  • Macrophytes play an important role in the ecosystems in which they occur, such as reservoirs and natural lakes and river. They are responsible for maintaining the natural balance, such as oxygenation, filtration, and removal of nutrients from the water, protection against erosive action of water on the banks, and acting as a food source and refuge for fish, birds and other organisms. Those plants are so relevant to the aquatic environments that their preservation is fundamental for the maintenance of biodiversity in these environments. However, in hydroelectric dams, the excessive presence of macrophytes in the reservoirs interferes to the multiple use of water and especially in the process of generating electricity.

    The proposal presented in this work consists of an innovative solution to the traditional techniques of removal and disposal of macrophytes present in hydroelectric reservoirs. One of the relevant innovations, in addition to the removal and transport method, is the use the biomass to generate biogas, which in turn will be converted into electricity, then promoting a more efficient destination for the aquatic plants, since they are currently treated as waste by most companies that operate hydroelectric plants.

    The proposal also includes a floating photovoltaic system, which will supply electricity to the macrophytes management system, and provide additional electricity to the energy generated from biogas, thus creating a hybrid system of renewable electricity generation. The hybrid system will have a surplus, meaning that it will be designed to generate more electricity than the system demand, which raises the need for storage or allocation of excess generation. After analyzing the available options, it was concluded that the connection of this hybrid system to the autotransformer of the hydroelectric plant's substation would be the best solution for the problem. This solution, however, requires a series of cautions and specificities for its implementation, which will be demonstrated throughout this work.

    The results of this work are conclusive. They are based on the results achieved from the project of implementation of macrophyte management system and the hybrid generation proposed.

20
  • GABRIEL CALDAS SARDINHA DE ALMEIDA
  • Robust Classification of Advanced Power Quality Disturbances in Smart Grids

  • Leader : PAULO FERNANDO RIBEIRO
  • MEMBRES DE LA BANQUE :
  • BENEDITO DONIZETI BONATTO
  • CARLOS AUGUSTO DUQUE
  • PAULO FERNANDO RIBEIRO
  • Data: 18 nov. 2021


  • Afficher le Résumé
  • The insertion of new devices, increased data flow, intermittent generation and massive
    computerization have considerably increased current electrical systems’ complexity. This
    increase resulted in necessary changes, such as the need for more intelligent electrical networks to adapt to this different reality. Artificial Intelligence (AI) plays an important role
    in society, especially the techniques based on the learning process, and it is extended to the
    power systems. In the context of Smart Grids (SG), where the information and innovative
    solutions in monitoring is a primary concern, those techniques based on AI can present
    several applications. This dissertation investigates the use of advanced signal processing
    and ML algorithms to create a Robust Classifier of Advanced Power Quality (PQ) Disturbances in SG. For this purpose, known models of PQ disturbances were generated with random elements to approach real applications. From these models, thousands of signals were generated with the performance of these disturbances. Signal processing techniques using Discrete Wavelet Transform (DWT) were used to extract the signal’s main characteristics. This research aims to use ML algorithms to classify these data according to their respective features. ML algorithms were trained, validated, and tested. Also, the accuracy and confusion matrix were analyzed, relating the logic behind the results. The stages of data generation, feature extraction and optimization techniques were performed in the MATLAB software. The Classification Learner toolbox was used for training, validation and testing the 27 different ML algorithms and assess each performance. All stages of the work were previously idealized, enabling their correct development and execution. The results show that the Cubic Support Vector Machine (SVM) classifier achieved the maximum accuracy of all algorithms, indicating the effectiveness of the proposed method for classification. Considerations about the results were interpreted as explaining the performance of each technique, its relations and their respective justifications.

21
  • PEDRO HENRIQUE CAMARGOS
  • Intelligent Systems for Monitoring and Fault Diagnosis of IEC 60034 / ISO 20816 Induction Motors

  • Leader : BENEDITO ISAIAS LIMA FULY
  • MEMBRES DE LA BANQUE :
  • BENEDITO ISAIAS LIMA FULY
  • CAIRO LUCIO NASCIMENTO JUNIOR
  • ELIANE VALENCA NASCIMENTO DE LORENCI
  • JOSE ROBERTO SANCHES MANTOVANI
  • MAURICIO CAMPOS PASSARO
  • Data: 26 nov. 2021


  • Afficher le Résumé
  • In industrial plants, engines are subject to failures that can cause production downtime causing economic losses. Predictive monitoring identifies these failures and reduces maintenance and operating costs. In this work, systems for monitoring and diagnosing faults in three-phase induction motors were developed based on the IEC 60034 and ISO 20816 standards. Through a pattern recognition neural network, the Operating Regions Diagnostic System classifies the region of operation of the motor. The Rotor Broken Bar Diagnostic System monitors the machine's state through a recurring neural network of short-term long memory, identifying the number of broken bars on the rotor and the operating zone according to ISO 20816. Finally, the Diagnosis \textit {Fuzzy} uses a neuro- \textit {fuzzy} system to predict the motor reduction factor, predicting possible failures that occur due to voltage imbalance.

22
  • EDUARDO MARCEL RESENDE
  • Robust State Estimation Based on Remote Monitoring via PMU and SCADA - Unified Solution in Complex Plane

  • Leader : ROBSON CELSO PIRES
  • MEMBRES DE LA BANQUE :
  • ANTONIO JOSE ALVES SIMOES COSTA
  • LUIZ CLAUDIO DE ARAUJO FERREIRA
  • ROBSON CELSO PIRES
  • ZULMAR SOARES MACHADO JUNIOR
  • Data: 30 nov. 2021


  • Afficher le Résumé
  • This work presents the implementation of classic (WLS) and robust (SHGM) estimators in the complex domain, considering remote monitoring of hybrid measurements via PMU and SCADA. For this, Wirtinger Calculus was the mathematical basis for turning non-analytical functions (power flow equations) concerning complex variables into multi-differentiated functions for complex and conjugate variables. Therefore, it enables expansion in the Taylor series. Thus, the classical (WLS) and robust (SHGM) estimation algorithms are derived in the complex domain, paying attention also to the processing of gross errors. In the classic complex estimator, the efficiency of the largest normalized residual test in identifying and recovering erroneous measurements is attested. For the robust complex estimator, a slight change in the former algorithm for calculating statistical projections is proposed for strengthening against bad leverage points. Projection statistics algorithm applied to a real- or a complex-valued Jacobian matrix provides different numbers and weightings assigned to leverage points. In addition, this work shows an efficient algorithm for analyzing the algebraic observability of the employed test systems, highlighting the applications in MATLAB and the potential contributions of such applications. The performance of complex-valued estimators was evaluated comparing with the same estimators built in the real plane. The test systems evaluated are IEEE-14, -30, -57, -118 and the SIN equivalents of 340, 730 and 1916 buses. Results show the computational advantages of the complex-valued estimator in scenarios of purely real, hybrid, or purely phasor measurements. Furthermore, the disparity between these numerical domains becomes more clear as the size of the system increases.

23
  • THAINANN HENRIQUE PEREIRA DE CASTRO
  • A CMOS Voltage and Current Reference using SCCTs and with VDD of 0.85V

  • Leader : ROBSON LUIZ MORENO
  • MEMBRES DE LA BANQUE :
  • HILTON DE OLIVEIRA MOTA
  • DALTON MARTINI COLOMBO
  • LUIS HENRIQUE DE CARVALHO FERREIRA
  • ROBSON LUIZ MORENO
  • Data: 6 déc. 2021


  • Afficher le Résumé
  • This work presents a topology of a voltage and current reference with little sensitivity in relation to operating temperature, supply voltage and the effects of CMOS fabrication processes. To achieve thermal compensation, a self-cascode composite transistor (SCCT) configuration is used, which is responsible for the generation of PTAT (proportional to absolute temperature) and CTAT (complementary to absolute temperature) voltages, which are summed through the aid of amplifiers operational (AmpOp) and current mirrors.

    The circuit provides an average voltage and current reference, measured values, of 483.58 mV and 1.317 μA with temperature coefficients (TC) of 25 ppm/°C and 77 ppm/°C respectively, operating in a temperature range from -30 °C to 100 °C, with a minimum voltage of 850 mV and average PSR at 50 Hz, -15.2 dB and -16.36 dB at 1.8 V for VREF and IREF respectively. The developed circuit area is 269 μm x 654 μm.

    It is presented in this dissertation, the project description, and pertinent simulations of the post-layout circuit of the proposed topology and its electrical characterization. The circuit was developed using a standard 180 nm CMOS process.

24
  • CAMILLA PEREIRA NAKANAMI
  • Analysis of the Impacts from the Installation of High Voltage Shunt Capacitors Bank Frontier Basic Network

  • Leader : BENEDITO DONIZETI BONATTO
  • MEMBRES DE LA BANQUE :
  • BENEDITO DONIZETI BONATTO
  • ELIANE VALENCA NASCIMENTO DE LORENCI
  • FERNANDO NUNES BELCHIOR
  • MAURICIO CAMPOS PASSARO
  • Data: 6 déc. 2021


  • Afficher le Résumé
  • The continuous verification of performance indicators and the minimum technical requirements required by the regulation of the electricity sector aim to list conditions that may affect the operation of the electric power system and the performance of its equipment. The result of this verification defines the actions of agents in that system and defines their responsibilities when accessing or remaining in this system. The regulation standard associated with access to systems establish the criteria, assumptions and limit values associated with performance indicators. The power factor, although monitored in steady state, provides an increase in electromagnetic transients in that system due to the switching of capacitor banks with the objective of providing adequacy of its value range. In this regard, the current regulation establishes that the transients of energization of shunt capacitor banks installed for power factor correction must not affect the performance of transmission installations or agents connected to the basic network and must not cause the overcoming of preexisting circuit breakers. In this way, it is proposed to determine a range of capacitive reactive power values that allow not exceeding the reference values assigned to the steady state voltage of the power system, to the energizing transients of the shunt capacitor banks and the transient recovery voltage in the circuit breakers adjacent to the busbar at 138 kV from the secondary of 2 basic network transformers at voltages of 440kV and 500 kV. The analyzes involved 2 load level scenarios. It concluded the 20 MVAr, 40 MVAr and 60 MVAr capacitor banks and filters do not promote a transgression of the limit values attributed to the steady state voltage in the border buses. In addition, under the conditions simulated in this work, the capacitor banks and filters do not support the overcoming of circuit breakers due to their energization currents and the transient recovery voltage for the proposed scenarios.

25
  • ALEXANDRE DEGAN FAVARO
  • Development and Implementation of a power quality monitoring system for decision making in transmission systems

  • Leader : PAULO FERNANDO RIBEIRO
  • MEMBRES DE LA BANQUE :
  • CARLOS AUGUSTO DUQUE
  • ELIANE VALENCA NASCIMENTO DE LORENCI
  • FERNANDO NUNES BELCHIOR
  • PAULO FERNANDO RIBEIRO
  • Data: 8 déc. 2021


  • Afficher le Résumé
  • The growing penetration of large blocks of renewable energy based on electronic inverters in power transmission systems can decrease the power quality of these systems, especially with increasing harmonic and interharmonic distortion and voltage fluctuation. Poor electrical power quality (PQ) can negatively affect the protection system and can cause premature aging of electrical equipment connected to the power system. Thus, continuous monitoring of the PQ and in real time can be of great value for the operation, maintenance and expansion of the power systems. This dissertation presents the real-time PQ monitoring system recently implemented in two transmission substations of the company TBE (Transmissoras Brasileiras de Energia) as part of the Aneel R&D project “Development of a monitoring system for power quality and decision-making in transmission lines” and which involved the participation of several researchers from UFJF, UNIFEI and UFSC. The monitoring system is based on the philosophy of Digitally Enabled Substation Architecture or Substation 4.0 (SB4.0). SB4.0 involves concepts of open architecture, vendor independence, interoperability, and scalability. The system developed for monitoring the PQ receives samples of voltage and current signals from a Merging Unit (MU) through the IEC 61850-9-2 (SV) protocol and calculates the various power quality parameters. As the system uses the SB4.0 concept, power quality monitoring is a software application implemented on an industrial computer. In addition, the system provides a Data Recording application, which runs as an additional software task that provides instantaneous Total Harmonic Distortion (iTHD) triggered oscillography. This dissertation presents the main aspects of the architecture of the system developed and implemented, as well as the field results obtained from the two monitored substations.

26
  • TALES HENRIQUE CARVALHO
  • Validation of Conditional Generative Networks for Segmentation of Optic Cup in Retinal Fundus Images

  • Leader : DANILO HENRIQUE SPADOTI
  • MEMBRES DE LA BANQUE :
  • CARLOS ALBERTO YNOGUTI
  • DANILO HENRIQUE SPADOTI
  • JOAO PAULO REUS RODRIGUES LEITE
  • RAFAEL CORRÊA DE ALMEIDA
  • Data: 9 déc. 2021


  • Afficher le Résumé
  • The evaluation of retinal fundus images represents an important task in ophtalmology, as it provides indication of eye-related pathologies. Among them, glaucoma stands out due to the need of an early diagnosis and early treatment, so severe vision symptoms can be avoided. Due to the high cost and low availability of retina specialists, automatic processes that identify adverse structures in retinal fundus images can aid the process of obtaining diagnoses. For glaucoma diagnosis, it is important to identify the dimension of the optic cup in the retina nerve head, as a ratio between optic cup and optic disc greater than 0.5 is a strong indicator of the condition. An automatic process depends on the segmentation between optic disc and optic cup in retinal fundus images, which provides the structures dimensions for calculating such ratio. This work proposes the usage of conditional generative adversarial neural networks for the retina segmentation task, based on Pix2Pix architecture. To validate the model, the proposed model was compared to U-Net and M-Net convolutional models, that represent the best results in literature. Results indicate that the generative model is capable of providing retina segmentation with precision comparable with state-of-art models, and it is capable of doing such task with higher robustness.

27
  • Matheus Antunes Pereira
  • Use of Fuzzy Logic in Estimating the Maximum Oil Temperature and Windings in Power Transformers

  • Leader : BENEDITO ISAIAS LIMA FULY
  • MEMBRES DE LA BANQUE :
  • BENEDITO ISAIAS LIMA FULY
  • CAMILA PAES SALOMON
  • ELIANE VALENCA NASCIMENTO DE LORENCI
  • JOÃO ALBERTO PASSOS FILHO
  • Data: 9 déc. 2021


  • Afficher le Résumé
  • Monitoring and maintenance of power transformers are of crucial importance for the proper functioning of the electrical system, preventing failures and unscheduled shutdowns, among the failures that can occur in the power transformers, several of which reflect on the transformer increasing the temperature. Several variables influence the increase in the transformer's internal temperature, such as ambient temperature, loading, humidity, pressure. Therefore, in this work, real ambient temperature data and the loading of a single-phase autotransformer (224MVA) were used to estimate the top-oil temperature and the hotspot winding using Fuzzy Logic. Subsequently, the comparison of the estimate made by Fuzzy Logic with the model of the IEEE C57.91 standard with constant and variable room temperature during the day was performed. Thus, obtaining an effective result, showing itself as a good alternative to the IEEE C57.91 standard, along with a suggestion regarding the use of constant room temperature throughout the day, as stated in the IEEE C57.91 standard.

28
  • FÁBIO FERREIRA MENDES DINIZ
  • Analysis of the Regulatory Impact on the Application of the Variable Part in the Public Electricity Transmission Service

  • Leader : BENEDITO ISAIAS LIMA FULY
  • MEMBRES DE LA BANQUE :
  • BENEDITO ISAIAS LIMA FULY
  • CAMILA PAES SALOMON
  • JOSE WANDERLEY MARANGON LIMA
  • JOÃO ALBERTO PASSOS FILHO
  • MAURICIO CAMPOS PASSARO
  • Data: 10 déc. 2021


  • Afficher le Résumé
  • The expansion of the transmission segment and the quality of the public electric energy service rendering of the Brazilian Electric System (SEB) have a fundamental role in the development and sustainability of the energy market.
    Such service is performed by the transmission concessionaires through the establishment of an Annual Allowable Revenue (RAP) that is directly linked to the full availability of its transmission assets for operation and coordination of the National Electric System Operator - ONS, as established in the Contracts for the Provision of Public Transmission Service (CPST).
    The first regulatory intervention in the transmission segment occurred through the publication of Normative Resolution 270/2007, which established the provisions for the quality of the public electric power transmission service, associated with the availability of the installations that are part of the Basic Grid.
    With the growing commercial operation of transmission assets in the National Interconnected System (SIN), since this branch has become attractive to national and international companies in the energy sector, it generated in 2016, through Normative Resolution no. 729/2016, changes in the regulation that deals with the calculation of unavailability of transmission equipment; this resolution would be rectified through Normative Resolution no. 782 of 2017 with the purpose of adjusting some rules and concepts.
    Due to the number of resolutions in force that govern the theme of electric energy transmission in Brazil, Normative Resolution no. 906 of 2020 was published, consolidating all the regulatory norms in a single document.
    The Variable Portion consists of an economic incentive for the maintenance of full availability of the transmission facilities. Its application is not characterized as a penalty for non-compliance with regulations, but as a regulatory incentive mechanism for the reduction of delay times for start-up, unavailability or operating restrictions. Thus, the application of the Variable Part does not depend on the assessment of fault or malice, and its calculation is directly related to the time of unavailability or operational restriction of the Transmission Function.
    Therefore, this work will address a history of the transmission segment, the calculation process of the unavailabilities performed monthly by ONS and, through indicators and statistical surveys of the disturbances and disconnections of the Basic Grid that occurred between the years 2013 and 2020, assess the performance of the Transmission Functions that have been in commercial operation since 2013 from a financial perspective, the impact of the Variable Installment for Unavailability on the revenues of the transmitters.
    Thus, the data and causes related to the occurrences in the Basic Grid, the average quantity of disconnections and the values accounted and discounted from the transmitters were analyzed, considering the economic incentive brought by the regulation, as well as the impacts of the evolution of this regulation on the availability of the Transmission Functions.

29
  • César Augusto do Carmo Santiago
  • IDENTIFICATION OF ISLANDED BUSES AND IN RING IN DISTRIBUTION SYSTEMS

  • Leader : ANTONIO CARLOS ZAMBRONI DE SOUZA
  • MEMBRES DE LA BANQUE :
  • ANTONIO CARLOS ZAMBRONI DE SOUZA
  • DIOGO MARUJO
  • PEDRO PAULO BALESTRASSI
  • Data: 14 déc. 2021


  • Afficher le Résumé
  • In the current scenario that includes the distributed energy resources inserted into electric power systems, microgrids along with energy storage systems and loads, they have become a solution with high potential in relation to its management from the perspective of distribution grids, besides being essential elements of the so-called new smart power systems. The presence of a management system, a supervisory center, that coordinates and automates the operation, whether the microgrid is connected or disconnected from the main grid is necessary for the operation of its components. This center ensures the ability of a microgrid to maintain the energy supply to its consumers, even in the event of an islanding or disruption of a transmission line, disconnected mode. This work presents a methodology capable of identifying possible islandings formed in a distribution system and monitoring each islanded subset enjoying in its optimal state. This methodology is based on a classificatory load shedding policy, i.e., the energy service is provided in order of priority so that essential services continue to be supplied in an adverse scenario. This work considers an algorithm to perform load shedding, which analyzes the energy balance of each island separately compared to the load of the allocated consumers. This balance uses the active power of the islanded bars as an artifice, as well as the active power of the customers. In this work the survival time of each islanding is approached independently, that is, the time of a subset does not influence another subset. For this, energy storage systems were used, which either charge or discharge at their maximum rate according to the islanding and meeting the demand. Finally, the results obtained express the effectiveness of the proposed method, certifying the energy supply that a microgrid can make available in terms of security and energy quality to its consumers. For the validation of the results, an IEEE test system was used.

Thèses
1
  • JOSE VITOR BERNARDES JUNIOR
  • Estimativa da Vida Útil Restante de Hidrogeradores

  • Leader : EDSON DA COSTA BORTONI
  • MEMBRES DE LA BANQUE :
  • ELIAS GEORGIOS STRANGAS
  • CREDSON DE SALLES
  • EDSON DA COSTA BORTONI
  • EDUARDO CRESTANA GUARDIA
  • GERMANO LAMBERT TORRES
  • JOSE FELICIANO ADAMI
  • Data: 23 févr. 2021


  • Afficher le Résumé
  • The monitoring of generators' condition is very desirable for a reliable operation of a hydropower plant. Maintenance activities can be scheduled to avoid unexpected failures that can lead to months or years of machines stopped without generation. Studies indicate that stator insulation is the leading cause of generator failure.
    In this sense, the proposal methodology's base is the monitorization of the actual health stage of the stator insulation system of hydro generators. Partial discharge tests in stator windings are applied to access the insulation condition. An algorithm to estimate the remaining useful life is the main contribution of this work. This estimation is based on both statistical evaluations of hydro generators and the stator insulation system's actual condition. Accelerated aging tests in stator specimens with wide variables acquisition are performed to understand the aging process. The proposed algorithm is tested in simulated cases and real data from a thermal cycle test, which observed an insulation breakdown.

2
  • CICERO LUIZ ALVES CUNHA
  • Surface acoustic wave devices based on aluminum nitride films deposited by plasma processes

  • Leader : TALES CLEBER PIMENTA
  • MEMBRES DE LA BANQUE :
  • MARCO ANTONIO RIDENTI
  • GILBERTO PETRACONI FILHO
  • JOSE ANTONIO JUSTINO RIBEIRO
  • LEONARDO BRESEGHELLO ZOCCAL
  • TALES CLEBER PIMENTA
  • Data: 5 mars 2021


  • Afficher le Résumé
  • The study of thin films of aluminum nitride (AlN) and devices constructed involving surface acoustic waves (SAW) technology is complex. However, this work serves as a basis for the development of SAW devices, such as filters with high selectivity, resonators, identification tags, delay lines, pulse compressors, different sensors (pressure, temperature, biosensors). Devices constructed on AlN films use wireless technology and are capable of operation in harsh environments without suffering degradation.
    The activity took place on four fronts: the first one refers to the synthesis of AlN thin films, and aimed at the establishment of criteria to characterize the deposition of AlN films by reactive RF magnetron sputtering; the second concerns the application of the techniques of analysis by X-ray diffraction (XRD), infra-red spectroscopy with Fourier transform (FTIR), Raman spectroscopy, profilometry and spectroscopy by Rutherford backscattering (RBS); the third front refers to the project of new SAW devices and Photolithography; the fourth is the acoustic characterization using a network Analyzer, and aimed at the determination of the SAW velocity, electromechanical coupling coefficient and frequency response of the devices. This work performed a study of the main problems involved in the deposition of aluminum nitride films, with good texturing AlN (100), and highly crystalline. It was studied the influence of the high SAW velocity of AlN films on the manufacture of SAW devices. The main characteristic parameters of the SAW devices performance, manufactured in the delay line configuration, were analyzed. It was suggested a new method of estimation of SAW speed based on the impulse response of the devices constructed. Hence this new method is more extensive than those found in the scientific literature.
    The results of the analysis of AlN films are consistent with those found in specialized literature. It was possible to construct SAW devices based on the AlN(100)/Si(100) structure. The SAW devices showed a satisfactory response in the frequency domain and their characteristic parameters were determined.

3
  • PAULO MARCOS PINTO
  • A design methodology for the Butterworth low-pass filter based on FDDTAs

  • Leader : LUIS HENRIQUE DE CARVALHO FERREIRA
  • MEMBRES DE LA BANQUE :
  • DALTON MARTINI COLOMBO
  • FABIANO FRUETT
  • GUSTAVO DELLA COLLETTA
  • LUIS HENRIQUE DE CARVALHO FERREIRA
  • ODILON DE OLIVEIRA DUTRA
  • ROBSON LUIZ MORENO
  • Data: 5 mars 2021


  • Afficher le Résumé
  • This work presents a design methodology for the Butterworth low-pass filter of any order, based on the differential-difference transconductance amplifier building blocks. Moreover, a similar design methodology for the high-pass Butterworth filter, using FDDTA, is also investigated. At first, the proposed methodology, the low-pass and high-pass Butterworth filter theories are presented, including state-of-the-art implementations and possible limitations of Butterworth filters. Then, the FDDTA is stated and its operation is evaluated, and a practical implementation using two fully differential inverter-based operational transconductance amplifiers (OTAs) is also investigated. This particular FDDTA implementation relies on two main features: the intrinsically matched transistors that assure similar transconductances and output conductances for both inverter-based OTA instances; and the inverter-based approach without internal nodes that reduces circuit complexity and power consumption since it requires no supplementary external calibration circuit such as tail current or bias voltage sources. Next, the Butterworth low-pass methodology, using FDDTAs, is demonstrated, showing that the proposed topology presents the expected transfer function according to the Butterworth low-pass filter theory. Following, the high-pass Butterworth filter architecture based on the FDDTA instance is also verified, demonstrating its possible feasibility, implementation, and limitations. Finally, intended to demonstrate the methodology functionality for the low-pass Butterworth, a fifth-order filter is implemented, which consists of one inverter-based OTA input stage and five FDDTAs in a cascade connection, showing that it presents the expected fifth-order transfer function according to the Butterworth theory. The prototype, implemented in a 130nm CMOS process, operates in weak inversion supplied with 0.25V and consumes 603nW. Furthermore, the filter features a DR of 57dB in a 100Hz bandwidth and a maximum THD of 54dB, therefore, accomplishing specifications that suit for low-frequency applications.

4
  • MATHEUS PENHA PEREIRA
  • Investigation of Faults Presented by Distribution Transformers in Lightning-Impulse Tests

  • Leader : ESTACIO TAVARES WANDERLEY NETO
  • MEMBRES DE LA BANQUE :
  • RAFAEL CONCATTO BELTRAME
  • CREDSON DE SALLES
  • ESTACIO TAVARES WANDERLEY NETO
  • GUSTAVO PAIVA LOPES
  • IVAN JOSE DA SILVA LOPES
  • JOSE MANUEL ESTEVES VICENTE
  • Data: 9 mars 2021


  • Afficher le Résumé
  • The work evaluates the conformity of oil-immersed distribution transformers with the lightning-impulse test. In this test, a considerable number of transformers show small discrepancies in the voltage and current oscillograms, in the form of high-frequency oscillations of short duration and low amplitude, creating doubts about how severe these oscillations are and their real damage to the transformer quality. Thereby, the work proposes a study to investigate the existence of correlations between these small indications of transformer failures, with results obtained in other tests adopted, called follow-up tests, and verifies if after the impulse test changes in the transformer quality were identified. To monitor the quality of the samples, the methodology of the work consists of the adoption of tests performed before and after the stress imposed by the impulse test. The test results are classified and evaluated based on the hypotheses created, using Fisher’s exact test. The proposed methodology was applied to 63 single-phase and three-phase distribution transformers, and based on the evaluations, there is favorable evidence for the correlation between partial discharges and high-frequency oscillations in impulse oscillograms. As for the association between the impulse test results with changes in the follow-up test, there is no evidence in favor of those discrepancies of the type high-frequency oscillations in the impulse oscillograms can cause changes in the results of the adopted follow-up tests. Therefore, the work recommends a more application of partial discharge tests as a resource to evaluate the quality of distribution transformers for laboratories and manufacturers before installation. Besides, the work defends the maintenance of the current conformity assessment methodology, when the presence of high-frequency discrepancies, in other words, argues that these discrepancies in the oscillograms should not be strictly taken into consideration for sample failure if they do not increase along of the normalized sequence of the impulse test.

5
  • PAULO VITOR GRILLO DE SOUZA
  • Methodology for Establishing New Base Impact Factors Considering Distribution System Clusters

  • Leader : JOSE MARIA DE CARVALHO FILHO
  • MEMBRES DE LA BANQUE :
  • AURELIO LUIZ MAGALHAES COELHO
  • DANIEL FURTADO FERREIRA
  • JOSE CARLOS DE OLIVEIRA
  • JOSE MARIA DE CARVALHO FILHO
  • ROBERTO CHOUHY LEBORGNE
  • THIAGO CLE DE OLIVEIRA
  • Data: 30 avr. 2021


  • Afficher le Résumé
  • Short-term voltage variations (STVVs) are events that affect the power quality and can cause great financial losses to industrial consumers who have loads sensitive to this disturbance, in addition to impairing the safety and reliability of processes. ANEEL, recognizing the importance of the matter, established through PRODIST the Impact Factor index to quantify the performance of the buses of a distribution system from the point of view of the STVVs. However, the base impact factor proposed in the regulation is unique, not considering the differences that the distribution systems have in relation to the potential cause of the event.
    In this context, this thesis presents a methodology for establishing different base impact factors for each distribution system. The work is focused on determining which variables best describe the disturbance and from these, establish clusters that allow a definition of more suitable base impact factors, considering the specificities of the distribution systems.
    To test the proposed methodology, real data from a concessionaire of the Brazilian electrical system was used. Nineteen substation bars were monitored through power quality meters.
    The methodology presented is generic and can be applied in any distribution system in Brazil, or even in other countries that may adopt an index similar to the impact factor.
    The results obtained in the case study showed that with the selected variables and the formed groups, it was possible to establish different base impact factors for each distribution system, which take into account the performance of similar systems.
    The application of the methodology brings benefits to the electricity sector, especially for consumers who have loads that are sensitive to short-term voltage variations, since it establishes basic impact factors that promote the improvement of the power quality.

6
  • GABRIEL CIRAC MENDES SOUZA
  • Deep Learning and Feature Engineering techniques applied to the Myoelectric Signal for accurate prediction of movements

  • Leader : ROBSON LUIZ MORENO
  • MEMBRES DE LA BANQUE :
  • ALEXANDRE MELLO FERREIRA
  • CARLOS HENRIQUE VALERIO DE MORAES
  • GABRIEL ANTONIO FANELLI DE SOUZA
  • JOEL JOSE PUGA COELHO RODRIGUES
  • ROBSON LUIZ MORENO
  • TALES CLEBER PIMENTA
  • Data: 13 juil. 2021


  • Afficher le Résumé
  • Pattern recognition techniques in the Myoelectric Signal (EMG) are employed in the development of robotic prostheses, and for that, they adopt several approaches of Artificial Intelligence (AI). This Thesis proposes to solve the problem of recognition of EMG standards through the adoption of profound learning techniques in an optimized way. The research developed an approach that extracts the characteristic a priori to feed the classifiers that supposedly do not need this step. The study integrated the BioPatRec platform (advanced prosthesis study and development) to two classification algorithms (Convolutional Neural Network and Long Short-Term Memory) in a hybrid way, where the input provided to the network already has characteristics that describe the movement (level of muscle activation, magnitude, amplitude, power, and others). Thus, the signal is tracked as a time series instead of an image, which allows us to eliminate a set of points irrelevant to the classifier, making the information expressive. In the sequence, the methodology developed software that implements the concept introduced using a Graphical Processing Unit (GPU) in parallel this increment allowed the classification model to combine high precision with a training time of less than 1 second. The parallel model was called BioPatRec-Py and employed some Engineering techniques of Features that managed to make the network entry more homogeneous, reducing variability, noise, and standardizing distribution. The research obtained satisfactory results and surpassed the other classification algorithms in most of the evaluated experiments. The work performed a statistical analysis of the outcomes and fine-tuned the hyperparameters of each of the networks. Ultimately, BioPatRec-Py provided a generic model. The network was trained globally between individuals, allowing the creation of a standardized approach, with an average accuracy of 97.83%.

7
  • MAÍRA RIBAS MONTEIRO
  • OPERATION AND RESTORATION OF BULK POWER SYSTEMS USING DISTRIBUTED ENERGY RESOURCES AND MULTI-MICROGRIDS

  • Leader : ANTONIO CARLOS ZAMBRONI DE SOUZA
  • MEMBRES DE LA BANQUE :
  • AHDA PIONKOSKI GRILO PAVANI
  • ANTONIO CARLOS ZAMBRONI DE SOUZA
  • BENEDITO DONIZETI BONATTO
  • ELIANE VALENCA NASCIMENTO DE LORENCI
  • JOAO GUILHERME DE CARVALHO COSTA
  • WALMIR FREITAS FILHO
  • Data: 30 juil. 2021


  • Afficher le Résumé
  • The fast-paced and meaningful penetration of distributed energy resources (DERs), such as variable renewable energy sources (RESs), concurrently with the widespread occurrence of natural disasters and man-made threats, has raised several challenges for the modern bulk power systems (BPSs) status quo. Although the DERs are demanding new solutions to ensure adequate stability and security levels, these resources enable significant opportunities to improve multiple BPS perspectives. In this view, seeking to capitalize on these novel features, while aware of the significant changes to BPS outlook, this thesis is focused on developing new methods able to capitalize on modern monitoring infrastructures, DERs and control areas opportunities toward the improvement of BPS operation, stability and restoration processes.
    Specifically, the thesis focuses on: 1) First, a novel method for the improvement of the static security region (SSR) is proposed based on a new network partitioning algorithm. The proposed algorithm focuses on modern BPS with high penetration of variable RES generation. It divides the BPS into coherence areas according to its criticality mapping, and consequently, areas are adaptively associated with SSRs generators groups. To this end, each bus is assigned a criticality index from the potential energy function, whereas this calculation is based on the data of the wide-area measurement system (WAMS) using phasor measurement unit (PMU); 2) Second, a novel area-based sensitivity index for voltage stability support is proposed, exploring both the network-wide sensitivity and the local characteristics of voltage collapse. The developed index focuses on the determination of the most effective buses for voltage support and their respective capability of increasing the system’s load margin. For this, a novel area-based outlook is developed taking advantage of the new possibilities enabled by BPS distributed controllable resources, such as flexible resources (FRs); 3) Third, a novel restoration strategy for interconnected transmission (TS) and distribution (DS) systems is proposed. The developed method capitalizes on multi-microgrids (MMGs) control areas to significantly improve the harnessing of frequency reserves available at the DS level to enhance the overall BPS restoration. For this, the proposed method coordinates the sharing of primary frequency (PFR) and secondary frequency (SFR) reserves between microgrids (MGs) and TS.

8
  • FABIO NORIKAZU KASHIWAGI
  • DEVELOPMENT OF A DEVICE TO GENERATE ELECTRICITY THROUGH MAGNETOHYDRODYNAMIC PHENOMENA

  • Leader : ESTACIO TAVARES WANDERLEY NETO
  • MEMBRES DE LA BANQUE :
  • LUIZA ADRIANA TELES DO REINO
  • ALAN MELO NÓBREGA
  • ALVARO ANTONIO ALENCAR QUEIROZ
  • CREDSON DE SALLES
  • ESTACIO TAVARES WANDERLEY NETO
  • MARIA ELENA LEYVA GONZALEZ
  • Data: 13 sept. 2021


  • Afficher le Résumé
  • Technology advances have allowed and made easier the miniaturization of the shape and size of electronic components to operate low power ranges. On the one hand, the trend of creating complex electronic systems with a high degree of processing, such as autonomous devices, medical apparatus and wireless sensor networks supplied by batteries, requiring low power to operate in the range from dozens of microwatt to hundreds of miliwatts appears as actions to reduce energy consumption. On the other hand, the Brazilian Electrical and Electronics Industry Association (ABINEE) estimates that the sale of batteries for residential use is around 1.2 billion units per year and the disposal of millions of these, mostly irregular, due to end of life or loss of charge after several recharges. In nanotechnology scale, new opportunities of power supply have launched for assistive technology and accessibility devices. The present work aims to build a microgenerator device working from the kinetic magnetic fluids energy based on a mixture of polyglycerol dendrimers (PGLyD) with superparamagnetic iron oxide nanoparticles (SPIONs) under an applied magnetic field, generating electric current of the order of microAmpère. The experimental results of the prototype proved to be promising and satisfactory.

9
  • CHRISTEL ENOCK GHISLAIN OGOULOLA
  • HVDC-LCC Transmission and Industrial Rectification: An Approach Employing New Topologies of High-Performance 24 and 48-Pulse Converters for Harmonic Mitigation

  • Leader : ANGELO JOSE JUNQUEIRA REZEK
  • MEMBRES DE LA BANQUE :
  • ADRIANA APARECIDA DOS SANTOS IZIDORO
  • BENEDITO ISAIAS LIMA FULY
  • JOSE CARLOS DE OLIVEIRA
  • MAURICIO CAMPOS PASSARO
  • ROBSON BAUWELZ GONZATTI
  • Data: 14 sept. 2021


  • Afficher le Résumé
  • Power quality improvement, reliability and availability of electrical power are significant
    concerns in power systems. In this context, multi-pulse converters are interface devices
    between the AC electrical system and the DC link, widely used in HVDC–TS (HVDC Transmission System) and industrial rectification of very high currents to meet harmonic
    requirements on both the AC and DC sides of the converter system. This thesis proposes
    24 and 48–pulse converter structures for reducing AC and DC filters in conventional
    HVDC–TS and for excellent harmonic mitigation in industrial rectification, respectively,
    using special three-winding transformers with ZZ–Y–D (ZigZag–Wye–Delta) or DE–Y–D
    (Extended delta–Wye–Delta) connection. To prove the feasibility and applicability of both
    proposed prototypes, computational simulations, under certain established operating conditions, are carried out in Matlab/Simulink to verify the theoretical studies carried out
    with the help of the MathCad program. Finally, a reduced-scale prototype implementation is performed and tested according to available laboratory resources to validate the proposed converter systems. According to the developed analyses, the results obtained showed a theoretical-experimental consistency in terms of power quality improvement and confirmed the feasibility and applicability of SC–24P (24–Pulse System Converter) and SC–48P (48–Pulse System Converter) proposed.

10
  • DAVI MARCELO FÉBBA
  • Nitride semiconductors as carrier-selective contacts for silicon heterojunction solar cells

  • Leader : EDSON DA COSTA BORTONI
  • MEMBRES DE LA BANQUE :
  • ADHIMAR FLAVIO OLIVEIRA
  • EDSON DA COSTA BORTONI
  • LUIS HENRIQUE DE CARVALHO FERREIRA
  • MARCO ANTONIO SCHIAVON
  • MATHIEU BOCCARD
  • RERO MARQUES RUBINGER
  • Data: 9 déc. 2021


  • Afficher le Résumé
  • This work initially reports the electrical characterization of ZnSnxGe1-xN¬2¬ (ZTGN) layers (10% < x < 90%) deposited on glass by combinatorial sputtering and further assesses the performance of silicon heterojunction (SHJ) solar cells featuring them as electron-selective contacts. Bandgap, dark conductivity, and the activation energy of the latter were found to significantly change between Sn and Ge-rich samples. When applying ZTGN layers as electron-selective contacts for SHJ solar cells, poor solar-cell performance was observed, with surprisingly similar results despite changes in material properties. From analysis and modelling of the current-voltage characteristics of several device structures, through a self-adaptive Differential Evolution algorithm, we show that the work function of the electron-selective contact lies around 4.35 eV for all investigated Sn and Ge contents, which is too high to form an excellent electron-selective contact. By comparing different solar-cell architectures, we could further identify that the Ge-rich layer imposes an additional barrier to electron extraction, independently of its poor selectivity, due to its low conductivity.
    After having identified these loss mechanisms, MgSnN2 (MTN) was envisioned as a good candidate, due to its high electron concentration and bandgap at 50% Mg/(Mg+Sn) (at.%). Thus, we fabricated MTN layers also through a combinatorial sputtering approach, with no substrate heating and at 200 °C, resulting in MgxSn1-xN2 (43% < x < 55%) samples, with bandgap around 2 eV, showing dark conductivity and activation energy that decreased towards Mg-rich samples. When applied to SHJ solar cells, JV characteristics similar to that when ZTGN was studied were obtained, and performance was slightly better. The limiting properties were also of the same kind, with an estimated work function around 4.16 eV, shifting to 4.3 eV for samples grown at 200 °C, and Sn-rich samples showing a too high electron affinity. Mg rich samples, as Ge-rich ones, resulted in strong s-shapes due to poor doping. Thus, doping these compounds with extrinsic elements appears as the most relevant approach to build efficient devices with a ZTGN or MTN contact layer.

2020
Thèses
1
  • GABRIEL FERREIRA ALVARENGA
  • Definition of clusters of generators toward security regions.

  • Leader : ANTONIO CARLOS ZAMBRONI DE SOUZA
  • MEMBRES DE LA BANQUE :
  • ANTONIO CARLOS ZAMBRONI DE SOUZA
  • ELIANE VALENCA NASCIMENTO DE LORENCI
  • MAURICIO CAMPOS PASSARO
  • WALMIR FREITAS FILHO
  • Data: 11 févr. 2020


  • Afficher le Résumé
  • This dissertation proposes a novel method towards the assessment of bulk power system coherence areas applied to the static security region (SSR). These regions are obtained through successive power flow solutions and its main objective is to verify the steady-state security conditions from different configurations of generation dispatch for a given constant demand. First, the construction process of the Static Security Regions, as well as the key aspects of the construction and relevant considerations that may significantly impact the analysis of the system performance, is presented in detail. As a second step, a partitioning algorithm applied to large transmission systems with high penetration of variable renewable resources is proposed. The proposed system partitioning is employed to adapt the generators group used for the system SSRs construction along with variations in the system operative conditions. This allows SSRs to consider the influence of renewables intermittency impact and countermeasure it by the adaptive modification of the generators group in a short-term horizon. To validate the proposed method the IEEE 118-bus system is employed considering modifications toward large penetration of renewables. The obtained results validate the proposed network partitioning method and indicate that the proposed adaptive SSR method leads to significant improvements in the system SSR in comparison with the traditional approach, significantly improving the operational region of bulk power systems with large penetration of renewable resources.

2
  • PAULO VICTOR VIANA DA SILVA
  • Electromagnetic procedures to support main components design of synchronous machines

  • Leader : EDSON DA COSTA BORTONI
  • MEMBRES DE LA BANQUE :
  • BERNARDO PINHEIRO DE ALVARENGA
  • EDSON DA COSTA BORTONI
  • JORGE JOHNNY ROCHA ECHEVERRIA
  • RICARDO ELIAS CAETANO
  • Data: 28 févr. 2020


  • Afficher le Résumé
  • Synchronous generators have proven over the decades to be the feasible solution for three-phase power systems and have consolidated as the vital piece in power plants in which the source of energy is renewable, as hydraulic or wind. Thus, with a constant increase in environmental concerns in current times, it is also expected an increase in synchronous machine usage, along with more research and development. A challenge would be to integrate the traditional consolidated knowledge with modern computational tools. Since when it comes to electrical machines, there is more than one procedure or technique to solve the same question, many combinations of new algorithms and books from a century ago have yet space to be approached. This work proposes and develops a set of tools to allow the analysis of magnetics effects in a salient pole machine with general, accurate, and fast solutions, applying what has been taught for the first “machinerists”, as Tingley and Park, alongside with MATLAB and Finite Element Method. Its objectives are to get Magnetomotive Force and Magnetic Flux Density of a given machine so then, in future work, to calculate the inductance matrix. MMF is calculated through Tingley Box, Winding Matrix, and Fourier Series, allowing the analysis for every single turn. Flux density is calculated through Finite Element Analysis, which allows the calculation of enclosure factors that support the accuracy of the tool by comparing it with manufacturers' benchmarks. In the end, a guide in MATLAB is shown, which aggregates everything exposed with a user-friendly interface.

3
  • BRUNA FERNANDA PINHEIRO

  • Analysis and Protection of a Synchronous Machine in Parallel with an Induction Machine in an Isolated System Modeled in RTDS

  • Leader : PAULO MARCIO DA SILVEIRA
  • MEMBRES DE LA BANQUE :
  • AURELIO LUIZ MAGALHAES COELHO
  • CARLOS ALBERTO VILLEGAS GUERRERO
  • FRANCISCO RICARDO ABRANTES COUY BARACHO
  • PAULO MARCIO DA SILVEIRA
  • Data: 31 mars 2020


  • Afficher le Résumé
  • This dissertation work evaluates the behavior and the protection of a synchronous generator in
    parallel with a self-excited induction generator feeding several types of loads, on an isolated system,
    all modeled on the Real Time Digital Simulator (RTDS). A field of recent studies that still has few
    works in development, especially using large machines, as in this dissertation work.
    To accomplish that, five operation scenarios were modeled from the main system and several
    disturbances were applied. The variation of synchronous machine excitation level and several short
    circuit faults in the system were simulated to analyze the machines response and the loss-of-field
    (ANSI 40) protection function and differential (ANSI 87G) protection function.
    The correct machinery initialization sequence was analyzed on this work, and the protection

    functions were tested by using a commercial generator protection relay connected by hardware-in-
    the-loop to the RTDS. The dissertation presents the necessity of initialize the induction machine as

    a motor, as well as the operational characteristics of the system including a synchronous generator
    in parallel with an induction generator and the master and slave relationship between them.
    The loss-of-field protection (ANSI 40) is tested by applying the reduction of 50% and 100% of the
    synchronous generator excitation. It was possible to analyze the non-acting of the protection ANSI
    40 due to the lack of reactive power in the system with only one SG in parallel with the IG, and the
    operation of the protection in the system with two synchronous generators in parallel with the
    induction machine.
    Furthermore, the differential protection function ANSI 87G was tested by applying line-ground,
    line-line and three-phase short circuits in several points of the system, in order to evaluate the
    protection behavior under the fault condition and to analyze the system behavior. After the
    application of the fault on the SG terminals, it is possible to verify the motorization of the IG after
    the protection function operates and removes the fault from the system.

4
  • VICTOR FERREIRA ZWETKOFF
  • Probabilistic Method for Transmission System Pricing Considering Intermittence of Wind Power Sources

  • Leader : ARMANDO MARTINS LEITE DA SILVA
  • MEMBRES DE LA BANQUE :
  • ARMANDO MARTINS LEITE DA SILVA
  • CARLOS RUBENS RAFAEL DORNELLAS
  • EDUARDO CRESTANA GUARDIA
  • JOAO GUILHERME DE CARVALHO COSTA
  • Data: 12 juin 2020


  • Afficher le Résumé
  • This dissertation proposes a new method for allocating costs of transmission systems considering the intermittency of wind sources. Initially, the mathematical formulation of the transmission cost allocation method is presented, which is based on that one currently adopted in Brazil. This method breaks down the total cost of the transmission system into two components: the cost of the used portion of the transmission capacity, allocated to users according to the actual use of the network; and the cost of the unused portion of the transmission, rated among users in proportion to the magnitudes of their generation and consumption.
    The main contribution of this dissertation is the insertion of a nodal transmission pricing scheme in a chronological simulation environment, which allows analyzing the behavior of transmission charges in relation to the variable power output of wind sources. The objective is to calculate an equivalent tariff for each market participant of generation and load sectors, considering the operational reality of the electrical system.
    The proposed method is applied to a modified configuration of the IEEE-RTS (Reliability Test System) with insertion of a wind power plant. In the same system, deterministic pricing methods are also applied, allowing the comparison among resulting tariffs. Several tests are carried out and their results extensively discussed.

5
  • VICENTE TIBURCIO DOS SANTOS JÚNIOR
  • Voltage control on active networks under adverse conditions.

  • Leader : ANTONIO CARLOS ZAMBRONI DE SOUZA
  • MEMBRES DE LA BANQUE :
  • ANTONIO CARLOS ZAMBRONI DE SOUZA
  • FERNANDO NUNES BELCHIOR
  • PAULO FERNANDO RIBEIRO
  • TALES CLEBER PIMENTA
  • Data: 16 juin 2020


  • Afficher le Résumé
  • Due to the inclusion of new loads and the predominant increase in electricity demand
    associated with the limitations of new environmental projects to minimize carbon emissions,
    such as pollution resulting from the energy generated by fossil fuels, the incorporation of
    electrical systems with distributed generation attributes to the energy planning, plans greater
    efficiency for various sectors of energy consumer groups worldwide.
    To maintain the effectiveness and reliable operation of the entire power system
    interconnected between grids and intelligent microgrids of electricity supply, standards must
    follow the established voltage levels in all terminals of the electrical power supply equipment
    supply, keeping them within limits. Both power utilities and distributed generation and
    consumers maintain the required design specifications for a reliable range of variation. The
    need to maintain a standardized voltage level is summed up in the treatment of possible
    failures that can occur when there is a voltage level acting beyond the limits established in
    extended equipment operating times.
    Due to the failure to maintain constant voltage levels along the electrical power grids
    several voltage control methods are applied, mainly controlling absorption, production and
    reactive power flow at all levels of the system, as well as when adverse system conditions
    where levels can achieve loss of system stability and voltage collapse.
    This research aims to characterize the appropriate methods for voltage correction and
    stability in active electrical networks under the influence of adverse conditions, whether
    natural influences or disasters, to influences related to the conditions of electrical energy
    systems, such as contingencies and distortions in other factors of the system that influence
    the level of voltage, to which some scientific publications relate [1-4], analyzing in an
    equationally calculated experimental way and simulations in MATLAB and ATPDRAW to
    prove the results.

6
  • DENIS VARISE BERNARDES
  • Optimization of the operation modes of the acquisition system of the SPARC4 instrument

  • Leader : DANILO HENRIQUE SPADOTI
  • MEMBRES DE LA BANQUE :
  • DANILO HENRIQUE SPADOTI
  • EDER MARTIOLI
  • LUCIANO FRAGA
  • MATEUS AUGUSTO FAUSTINO CHAIB JUNQUEIRA
  • Data: 30 juin 2020


  • Afficher le Résumé
  • This work presents a methodology developed to optimize the performance of the EMCCDs of the SPARC4 instrument. It was developed two packages in Python to calculate the signal-to-noise ratio and the acquisition rate of the CCDs, according to its operation mode. Each of these packages are used in the optimization of the parameters of the CCDs. It has been developed the following three methods for optimization: (1) optimize the signal-to-noise ratio, (2) optimize the acquisition rate, and (3) optimize both parameters at the same time. The latter uses the Bayesian Optimization Method to determine the optimum mode. It has been performed a series of tests to validate the method. To accomplish these tests, it has been developed an artificial image simulator to simulate a star image acquired by the cameras. After the tests, it has been applied the method to optimize the operation
    mode of the CCD for a series of archival data from several nights of observations carried out at the Picos dos Dias Observatory. It was possible to obtain an improvement in the CCD performance for all nights analyzed. We show that if this method was used as a tool to optimize the operation mode of the CCDs, it would have been possible to save an amount of telescope time equivalent to 97.17 %, 65.08 %, and 77.66 %, for optimizaton modes 1, 2, and 3, respectively. We conclude that this method can be used to determine the operation mode of the SPARC4 CCDs, where it can contribute to an improvement in the quality of the scientific data acquired at the observatory as well as in the allocation of larger projects for the same number of nights.

7
  • BRUNO PINTO BRAGA GUIMARÃES
  • Energy storage system based on Multilevel Converter for Medium Voltage Grids

  • Leader : LUIZ EDUARDO BORGES DA SILVA
  • MEMBRES DE LA BANQUE :
  • CARLOS HENRIQUE DA SILVA
  • LUIZ EDUARDO BORGES DA SILVA
  • ROBSON BAUWELZ GONZATTI
  • RONDINELI RODRIGUES PEREIRA
  • WILSON CÉSAR SANT`ANA
  • Data: 2 juil. 2020


  • Afficher le Résumé
  • This work presents the development of a seven-level CHB multilevel converter prototype, for applications with battery energy storage systems in medium voltage grids. The specification of each component that composes the power stage of the equipment, as well as the description of the circuits that compose the electronic measurement and control system, are described in detail. To demonstrate the functionality of the implemented prototype, results are presented injecting active power into a 13.8 kV system and charging the battery banks during scheduled times. The system has a GPS set to provide time information to perform the transition of the active power support and battery charging mode. The implemented function is based on the control of active current manipulated
    by the converter. For it, is used the proportional resonant controller together with an algorithm that coordinates charge and discharge of battery banks. The implementation of the control loop and the control algorithm is performed in the TMS320F28335 microcontroller. Finally, results are also presented to demonstrate the possibility of using this equipment for reactive power compensation and system’s voltage regulation.

8
  • VINICIUS BRAGA FERREIRA DA COSTA
  • Economic modeling of the Smart Electricity Market with power distribution utilities, consumers and prosumers

  • Leader : BENEDITO DONIZETI BONATTO
  • MEMBRES DE LA BANQUE :
  • ANTONIO CARLOS ZAMBRONI DE SOUZA
  • BENEDITO DONIZETI BONATTO
  • FERNANDO NUNES BELCHIOR
  • Data: 3 juil. 2020


  • Afficher le Résumé
  • The integration of distributed generation (DG) into the distribution network has been increasing intensely, especially the photovoltaic generation, due to the reduction of technology costs, economic incentive policies and the growing concern regarding the environment. Although the benefits of inserting renewable energy sources into the network are unquestionable, it is essencial to have an effective regulation that ensure the sustainability of the market formed by prosumers (consumers who own DG systems), consumers and power distribution utility. The current tariff regulation (Net Metering) states that the surplus energy from the DG system must be compensated by the utility, leading to credits on the energy bill. The utility receive and distribute the energy into its network and the prosumer has up to 5 years to consume the energy credit during the same respective tariff period. As the number of prosumers increases, the utility’s revenue deacreses, resulting in a tariff raise by the regulatory agency in the next tariff review cycle, which acts to guarantee the utility’s economic and financial balance. The tariff raise encourage even more consumers to purchase DG systems, which again implies in a decrease of the utility’s revenue. This process is popularly referred to as “Reverse Robin Hood”, since it results in massive social impacts, and the most affected consumers are those who cannot afford to buy and install DG systems. This dissertation aims to start the representation of the smart market of the electric sector based on the Optimized Tariff Model (TAROT), with the objective of maximizing the socioeconomic welfare and ensuring the sustainability of the market, only attainable with more efficient regulation.

9
  • JOÃO GABRIEL LUPPI FOSTER
  • FCS-MPC Applied to Multilevel Hybrid Active Power Filter for Harmonic and Reactive Power Compensation

  • Leader : LUIZ EDUARDO BORGES DA SILVA
  • MEMBRES DE LA BANQUE :
  • LUIZ EDUARDO BORGES DA SILVA
  • ROBSON BAUWELZ GONZATTI
  • RONDINELI RODRIGUES PEREIRA
  • SÍLVIA COSTA FERREIRA
  • Data: 6 juil. 2020


  • Afficher le Résumé
  • This work proposes the application of finite control set model predictive control(FCSMPC)
    for dynamic reactive power and harmonics compensation. To achieve these objectives
    the FCS-MPC is applied to a hybrid active power filter consisting of a capacitor
    bank, an LCL filter and a multilevel converter.
    The reactive power control is accomplished through control of the capacitor bank voltage,
    in this way it is possible to deliver reactive power greater or smaller than the nominal
    power of the capacitor bank. The source current harmonics compensation is based on two
    principles: harmonic blocking, which prevents grid voltage harmonics from generating
    harmonic currents in the source; and filter tuning, which turn the hybrid filter branch
    into a short circuit for the load harmonic currents, avoiding them to penetrate the grid.
    A multivariable control is applied in order to reduce the problems with the LCL filter
    resonances. The control references for the fundamental frequency are obtained from the
    system model, and a proportional resonant control is applied to calculate the references
    for the harmonic frequencies.
    Simulations and experimental results are presented in order to verify the behaviour of the
    applied techniques.

10
  • CLÁUDIO ADRIANO CORREIA CAMBAMBI
  • IMPACT OF SHADOWING ON THE OUTPUT POWER OF A PHOTOVOLTAIC MATRIX WITH BYPASS DIODES

  • Leader : ENIO ROBERTO RIBEIRO
  • MEMBRES DE LA BANQUE :
  • ENIO ROBERTO RIBEIRO
  • PAULA DOS SANTOS VICENTE
  • PAULO FERNANDO RIBEIRO
  • ROBSON LUIZ MORENO
  • Data: 17 juil. 2020


  • Afficher le Résumé
  • It is true that the partial shading of a photovoltaic matrix reduces the power generation capacity. It is believed that the maximum power of a partially shaded photovoltaic matrix is inversely proportional to the percentage of shading. However, it appears in the literature that this may not be the case. The maximum power of a matrix can be rendered insensitive to the percentage of shading if a critical point is reached, and that critical point depends on the size, number of shaded modules and the configuration of the matrix. It is constantly reported in the literature that in a photovoltaic matrix under shading conditions, the condition with the least impact occurs when the shaded modules are located in the same column or distributed in a limited number of columns. In fact, this observation is 100 % true for photovoltaic arrays without the use of the bypass diode. As demonstrated in this dissertation, the condition with the least impact can also occur when the shaded modules are distributed in different columns if the bypass diodes are used in the configuration. Thus, this dissertation presents the relationship between the position and the number of shaded modules versus the energy generated by a partially shaded series-parallel photovoltaic matrix and establishes a set of analytical equations to estimate the voltage, current and power at each point. maximum local power, using only information from the data sheet, in the simplest and most direct way, without resorting to
    complex modeling, completely avoiding the iterative procedure, eliminating calculation uncertainty and significantly reducing execution time. Derived expressions are validated through simulations. It was found that the loss of output power is directly and mainly related to the position of the shaded modules in the photovoltaic matrix.

11
  • RAISSA FERRAZ CAMPOS
  • Development of a Control System applied to an Active Knee Prostheses

  • Leader : LUIS HENRIQUE DE CARVALHO FERREIRA
  • MEMBRES DE LA BANQUE :
  • CAIO FERNANDES DE PAULA
  • FELIPE DE OLIVEIRA E SILVA
  • JEREMIAS BARBOSA MACHADO
  • LUIS HENRIQUE DE CARVALHO FERREIRA
  • Data: 24 juil. 2020


  • Afficher le Résumé
  • In Brazil the number of lower limb ablations performed in the public health system is prevalent among surgeries of this type, with transfemoral amputations having the highest incidence. With the loss of a considerable part of a lower limb, body’s balance and stability are drastically affected. The attempt to compensate the loss affects patients’ body biomechanics and the deprivation of mobility directly influences its quality of life. Over the years, efforts to enlarge transfemural amputee patients’ quality of life have grown and numerous researches have been carried out, benefiting prosthetic development that tries to compensate the limb loss or at least to mitigate the influences on body biomechanics. Limb prostheses can be passive, semi-active and active, being the last mentioned the most appropriate to provide an experience very close to the natural one to its users. Magneto-rheological fluids are a class of intelligent materials, whose main characteristic is to change from a liquid to a semi-solid state through the application of a magnetic field. Its advantages make its use very promising in several implementations, such as in the field of prosthetic devices. This study presents the development of a control system for a magneto-rheological knee that aims to be subsequently applied in an active transfemoral prosthesis. The system uses neural networks and predictive control techniques, that brings the skills of learning, forecasting, self-organization, the ability to predict and guarantee the behaviour of the system within the prediction horizon. Together these two techniques enable a refinement of the control system. In order to assure its correct functioning, torque and knee positioning controls are performed, which acting as sub-systems are responsible for ensuring that the engine is able to provide sufficient torque to perform the movements and the leg could be properly positioned during every gait cycle. The two sub-systems acting simultaneously and steadily can guarantee that all system requirements are met. Different network arrangements are tested using Long Short-Term Memory, Gated Recurrent Unit and simple recurrent layers. The results showed that the magneto-rheological knee can be controlled using the techniques presented, which demonstrates its application in real prostheses is feasible and promising.

12
  • PEDRO HENRIQUE NAVES VASCONCELOS
  • Integrated Dynamic Modeling of Economic, Social, Demographic, and Environmental Aspects for a Sustainable Regional Development

  • Leader : ANTONIO CARLOS ZAMBRONI DE SOUZA
  • MEMBRES DE LA BANQUE :
  • ANTONIO CARLOS ZAMBRONI DE SOUZA
  • LUIS VARGAS DÍAZ
  • PAULO FERNANDO RIBEIRO
  • PEDRO PAULO BALESTRASSI
  • Data: 30 juil. 2020


  • Afficher le Résumé
  • A broad understanding of the underlying mechanisms that relate poverty to economic, demographic, and environmental aspects is crucial in the deployment of policies and interventions to eradicate extreme, pervasive poverty and contribute to regional development. To test and visualize existing theories of poverty traps – the poverty that is self-reinforcing due to poor equilibrium conditions – we take the challenge of modeling using system dynamics theory. The Wonderland model sets the base framework for the proposed equations and parameters. Previous work has successfully mathematically modeled some interactions between economy, demography, and environment, but the inclusion of poverty and poverty traps and their respective effects on a broader point of view is a somewhat novel approach. The proposed model is tested under estimated conditions of a real Brazilian scenario. In simulations, large time-scales were used in visualizations of the
    effects of policies and interventions upon future generations. Results illustrate that the dynamics of poverty can be better understood and addressed by mathematical models and contribute to investigate regional development and the relationship between different aspects of the region. The modeling of poverty traps and the sustainable development using system dynamics requires a holistic view, as it aggregates aspects that transcend the dynamics of economics, expert, engineering and social systems.

13
  • HARISON ARAÚJO ANTUNES
  • Methodology for Monitoring and Investigating Failures in Transformers: contribution of root cause analysis to predictive maintenance

  • Leader : ESTACIO TAVARES WANDERLEY NETO
  • MEMBRES DE LA BANQUE :
  • ESTACIO TAVARES WANDERLEY NETO
  • GUSTAVO PAIVA LOPES
  • PABLO RODRIGUES MUNIZ
  • ROBSON DA SILVA MAGALHÃES
  • Data: 7 août 2020


  • Afficher le Résumé
  • Power transformers are generally the most expensive assets in an electrical system, in addition to being critical to the operation of the system or an industry in which an unscheduled shutdown can bring enormous economic damage. Thus, the detection of incipient failures and the verification of the condition of the equipment to avoid untimely stops are essential and can be achieved through periodic tests. The preventive and predictive maintenance of electrical transformers with the application of conventional techniques for analysis of gases dissolved in insulating oil are capable of indicating the types of failures: overheating, low intensity partial discharges, among others, however they do not identify the root cause of the diagnosed effects. Given this, there is the possibility of greater gains combining the predictive diagnosis with the technique of searching for the root cause of the failure, aiming at obtaining more in-depth diagnoses, allowing the blocking of the root cause. For this purpose, this dissertation proposes a methodology for monitoring and investigating failures in transformers. Therefore, it is expected that the use of the proposed tool will avoid the repetition of the problem or allow the anticipation of failure in other similar equipment. The proposed methodology is used in real cases, which demonstrates its great efficiency compared to conventional diagnostic techniques.

14
  • SAMUEL DE SOUZA LIMA MOREIRA
  • Coexisting Analysis of 5G Waveforms with ISDB-T System in TV White Spaces.

  • Leader : TALES CLEBER PIMENTA
  • MEMBRES DE LA BANQUE :
  • CARLOS NAZARETH MOTTA MARINS
  • ROBSON LUIZ MORENO
  • ROMULO MOTA VOLPATO
  • TALES CLEBER PIMENTA
  • Data: 7 août 2020


  • Afficher le Résumé
  • The efficient use of the electromagnetic spectrum becomes increasingly necessary due to the increase number of cellular devices. One possible solution is the opportunistic spectrum use in the VHF and UHF bands, allocated for television broadcasting. Therefore, it is necessary to evaluate the concurrent operation of broadcasting and mobile communication systems. This work aims to identify, analyze and measure the interoperability between those systems, by evaluating the feasibility of coexistence of different types of services. In this article, evaluations were made on two major candidates for the next cellular generation, the GFDM and the F-OFDM, operating along with the Integrated Services Digital Broadcasting Terrestrial – ISDB-T standard. The results show the flexibility of the GFDM and F-OFDM waveforms over the OFDM waveform, thus enabling opportunistic use of the spectrum over licensed and unlicensed users

15
  • THAIRONI MENEZES DE BRITO
  • A CMOS voltage reference utilizing self-cascode composite transistor and Schottky diode

  • Leader : ROBSON LUIZ MORENO
  • MEMBRES DE LA BANQUE :
  • DALTON MARTINI COLOMBO
  • FABIANO FRUETT
  • LUIS HENRIQUE DE CARVALHO FERREIRA
  • ROBSON LUIZ MORENO
  • Data: 27 août 2020


  • Afficher le Résumé
  • This work shows a study of temperature behavior of self-cascode composite transistors (SCCTs) and Schottky diode in order to generate both PTAT and CTAT voltages of a temperature-compensated voltage reference. The SCCTs study also shows that it is possible to obtain a compensated voltage with a proper sizing and biasing of the SCCT. The voltage reference was designed based on achieved results and it was fabricated in a 130 nm CMOS process. The circuit occupies an area of 67.98 µm x 161.7 µm and it was measured in temperature and power-supply variation. A trimming circuit also is added to the reference in order to adjust the temperature coefficient (TC). The averaged output voltage is 720 mV with a VDD of 1.1 V. The averaged TC is 56 ppm/ºC in a temperature range of -40 to 85 ºC. The circuit works in a power-supply range of 1.1 to 2.5 V and its power consumption is 750 nW.

16
  • ARTUR ATILA MORAES
  • Simulation in MATLAB/Simulink of the Regenerative Braking of a Permanent Magnet Synchronous Motor Applied to the Vehicle of UNIFEI's EcoVehicle Team

  • Leader : LUIS HENRIQUE DE CARVALHO FERREIRA
  • MEMBRES DE LA BANQUE :
  • CAIO FERNANDES DE PAULA
  • FELIPE DE OLIVEIRA E SILVA
  • LUIS HENRIQUE DE CARVALHO FERREIRA
  • Data: 28 août 2020


  • Afficher le Résumé
  • This work presents a simulation in MATLAB/Simulink environment of a model based on an electric vehicle, E-Power V1, built by the EcoVeículo team. Initially, the history of electric vehicles is introduced until it reaches its current moment of high relevance and demonstrating the reason for still having the disadvantage of having a low autonomy. Based on this, the work is justified by proposing a way to recover energy through regenerative braking, using the VE model of the EcoVeículo team as a model. Thus, the work demonstrates the basic principles of electric motors, focused on the synchronous motor of permanent magnets. Three techniques (single-switch, two-switches and three-switches) of regenerative braking and the equation of the main forces acting on the model are also demonstrated. Finally, the parameters used in the modeling and assembly of the simulation through blocks and functions in MATLAB / Simulink environment are exposed. Through simulation, the results of energy efficiency, accommodation time, electrical torque and error in steady state are presented, being less than 1% in all techniques. In the conclusion, it is discussed the possibility of, as a future work, implementing the three-switches technique, which was more successful in energy recovery, reaching 79.1% of energy efficiency with 3678W recovered, in addition to the advantage of being the only technique sensorless. In this way, the work contributes to the EcoVeículo team by implementing regenerative braking technology in a simulation of the E-Power V1 electric vehicle and showing the competitive advantage when using the technique.

17
  • LUCAS DE PAULA SANTOS PETRI
  • Algorithm for the Estimation of the Severity Degree of Partial Discharges in High Voltage Insulators

  • Leader : ESTACIO TAVARES WANDERLEY NETO
  • MEMBRES DE LA BANQUE :
  • BENEDITO ISAIAS LIMA FULY
  • CREDSON DE SALLES
  • EDSON GUEDES DA COSTA
  • ESTACIO TAVARES WANDERLEY NETO
  • JOSE FELICIANO ADAMI
  • Data: 25 sept. 2020


  • Afficher le Résumé
  • This study makes use of artificial neural networks, a machine learning algorithm, for the classification of signals of partial discharges in high voltage insulators. In addition to that, these signals are further analyzed by means of implementations in Python programming language, seeking to define a severity degree for the partial discharge activity using a fuzzy inference system. The case study of this work is the city of São Luís, capital of the state of Maranhão, whose electric system is under concession of Equatorial Energia. The utility’s service area comprises a 69 kV transmission system, whose structures employ composite line post or suspension insulators. Partial discharges not only cause the degradation of the polymeric surface of the insulators, but can also evolve to extensive arcing, which can further cause flashovers that result in system faults and energy supply interruptions. This work has proposed the development of data acquisition and analysis algorithms for partial discharge signals, to compose an inspection instrument that can be used in the field by means of a compact and portable software-hardware system and an antenna for the acquisition of radiofrequency interference signals from discharge activity. Thus, the utility’s maintenance team will have a decision support tool to assess the structures condition, thus enabling the scheduling of preventive maintenance routines, if necessary, seeking to prevent power supply interruption events. From laboratory tests and field collected data, some results are presented, showing the consistency of the parameters selected to calculate the severity index. The increase of the severity degree is observed with the aggravation of surface pollution and rise of relative humidity.

18
  • ELISA LEFOL NANI CARVALHO
  • Testing Methodology for a Power Quality Management System

  • Leader : PAULO MARCIO DA SILVEIRA
  • MEMBRES DE LA BANQUE :
  • AURELIO LUIZ MAGALHAES COELHO
  • FREDERICO OLIVEIRA PASSOS
  • JOSE CARLOS DE OLIVEIRA
  • PAULO MARCIO DA SILVEIRA
  • Data: 28 sept. 2020


  • Afficher le Résumé
  • The increased sensitivity of equipment to electrical disturbances and the spread of nonlinear loads are some of the factors that reinforce the importance of Power quality (PQ). Poor power quality can lead to equipment damage, interruptions and other consequences causing monetary losses and possible legal actions. Therefore, monitoring the PQ status in power grid is a strategic factor, while it allows the identification of critical areas. The different types of meters, the massive amount of data and the many PQ indices defined by PRODIST (Brazilian standard for power distribution) make the PQ management a difficult task to be accomplished efficiently without an automatic power quality management system (PQMS). In this concern, this work presents a review on the projects that have been developed around the world regarding power quality data monitoring and management. This work also presents a proposal for PQMS addressing data acquisition, PQ indices calculation algorithm and a human machine interface for displaying results in a user-friendly format. Considering that the PQ indices take at least a week to be determined, the process of testing and validating the developed system would be timeconsuming and inefficient if it were performed using real measurement data. Hence, this work proposes and applies an efficient methodology for the PQMS validation using a PQ test bench in order to test all the software functions in an optimized way. The challenges encountered and the results obtained during the PQMS validation process are also presented and discussed.

19
  • TIAGO DOS SANTOS SILVERIO LINO
  • COMPARATIVE ANALYSIS OF DOUBLE CIRCUIT TRANSMISSION LINE TELEPROTECTION SCHEMES THROUGH A REAL-TIME SIMULATION STRUCTURE BASED ON IEC 61850-90-1

  • Leader : PAULO MARCIO DA SILVEIRA
  • MEMBRES DE LA BANQUE :
  • CARLOS ALBERTO VILLEGAS GUERRERO
  • LUIS HENRIQUE LOPES LIMA
  • PAULO MARCIO DA SILVEIRA
  • RONALDO ROSSI
  • Data: 29 sept. 2020


  • Afficher le Résumé
  • Teleprotection Schemes were developed aiming to improve the performance of transmission line protection, which is achieved through an appropriate choice of them. Through real-time digital simulation, this dissertation brings a practical analysis and a comprehensive view of the main aspects related to the commonly applied Teleprotection Schemes, highlighting the minimum requirements established by the Brazilian National System Operator (ONS) and providing an aid in the selection of the scheme to be used. Due to the fact that most of transmission lines of the National Interconnected System are parallel circuits, this thesis considers not only an analysis of system with a single circuit line, but also a real double line circuit system. In addition, this work highlights the effect of zero sequence mutual coupling in the impedance measurement of the relays’ distance function and, consequently, the effect in Teleprotection Schemes. The tests involve protection relays from two renowned manufacturers and takes into consideration two teleprotection structures: the conventional one and the structure based on communication mechanisms exposed in IEC 61850-90-1 Standrad, providing a survey of benefits obtained from this replacement.

20
  • PAULO ANDRADE NOVAES
  • Control strategies in support of reactive power from wind generation and its impact on the voltage stability of the Basic Grid using security regions: an application in the Northeast Region of Brazil

  • Leader : ANTONIO CARLOS ZAMBRONI DE SOUZA
  • MEMBRES DE LA BANQUE :
  • ANTONIO CARLOS ZAMBRONI DE SOUZA
  • JORGE LUIZ DE ARAUJO JARDIM
  • PAULO FERNANDO RIBEIRO
  • Data: 13 oct. 2020


  • Afficher le Résumé
  • This dissertation presents a discussion about some technical characteristics of the wind turbines, their electrical and energetic implications and how these equipments can contribute in a static and dynamic regime from the point of view of voltage stability for the performance of electrical power systems focusing on the Northeast Region of Brazil. Throughout this dissertation, different energy scenarios and configurations of systems are presented based on the Brazilian Electric System in 2020.
    The massive insertion of intermittent renewable sources, mainly in the Northeast Region, has been changing the operating conditions of this system in view of the behavioral profiles intrinsic to these sources, with high quotas being added every year in view of the large "wind fields" available in this region.
    Despite contributing to the increase in generation capacity from an energy point of view, this source adds little or no inertia to the system, which reflects stability in the face of disturbances, resulting in risk conditions for the regulation and control of voltage stability and consequently operational security of the network. In view of this, voltage stability has become a point of concern, arousing the interest of engineers and researchers worldwide.
    The control resources in the reactive power support present in the network are not always sufficient to accommodate this entire generation. That is why it is studied here the performance of the control strategies of the reactive power support of the wind turbines in order to assist in mitigating the effects caused by voltage instability in an attempt to increase the safety margin of the system. In order to provide an assessment of the conditions of safe operation, in different electroenergetic scenarios where wind power is present, the use of the Safety Regions feature is used, enabling a representative and safe mapping of the analyzed system and subsidizing the decision making of the operation.
    In a static regime, the voltage and load levels are evaluated in situations of increase and reduction of wind generation in the Northeast through the Security Regions. In a dynamic regime, where the study begins with the presentation of wind turbines in three different control strategies that assist in regulating the voltage of the machine and in turn of the system in which it is inserted. This analysis has three distinct cases in the Northeast where wind behavior differs from each other to illustrate the impact they can cause on the dynamic performance of a system.
    The results obtained from the simulations show significant gains in improving the performance of the electrical system in the Northeast Region with the increase in the generation runoff margin, in which the wind turbines operate.

21
  • MARCOS LEONARDO RAMOS
  • EIGHT-THYRISTOR AC-DC MODIFIED CONVERTER BRIDGE IMPLEMENTATION FOR POWER FACTOR IMPROVEMENT

  • Leader : JOSE MARIA DE CARVALHO FILHO
  • MEMBRES DE LA BANQUE :
  • ANGELO JOSE JUNQUEIRA REZEK
  • JOSE CARLOS GRILO RODRIGUES
  • JOSE MARIA DE CARVALHO FILHO
  • VINICIUS ZIMMERMANN SILVA
  • Data: 29 oct. 2020


  • Afficher le Résumé
  • The purpose of this work is the development and the implementation at laboratory the one full-controlled test bench to operate as a controlled modified bridge and as a conventional bridge and check the power factor improvement the controlled modified bridge in comparison the conventional bridge, considering for both the same average DC output voltage criterion. Also, other experimental results will be evaluated, such as: displacement factor, input voltage and current waveform, output voltage waveform, current harmonic distortion, current harmonic spectrum, auxiliary firing control circuit topology.
    The main motivations for carrying out this work are: to check experimentally the improvement of the power factor of the modified bridge in comparison to the conventional bridge; to purpose an alternative topology for the auxiliary firing control circuit; to compare the auxiliary firing control circuit to the main firing control circuit.
    The test bench is an AC-DC converter bridge that works as a rectifier, Graetz configuration, powered by a 4-wire three-phase electrical system. The test bench is equipped with eight thyristors and two independent firing control circuits. The eight thyristors, six are phase thyristors and two are neutral thyristors; the two independent firing circuits, one is a main firing control circuit for phase thyristors, the other is an auxiliary firing control circuit for neutral thyristors.
    The bench works in two operating modes; in operating mode 1, it works as a modified bridge, in which six phase thyristors, two neutral thyristors, one main firing and one auxiliary firing are working; in operating mode 2, it works as a conventional bridge, in which six phase thyristors and one main firing are working, but the neutral thyristors and auxiliary firing are ineffective.

22
  • DENISON GIMENES MESQUITA
  • Measurement of Losses in Dry-type Air-Core Reactors using Infrared Thermography Method

  • Leader : EDSON DA COSTA BORTONI
  • MEMBRES DE LA BANQUE :
  • ANDRE LUIS MARQUES MARCATO
  • EDSON DA COSTA BORTONI
  • MARCOS VINICIUS XAVIER DIAS
  • Data: 23 nov. 2020


  • Afficher le Résumé
  • Dry-type air-core reactors, as well as capacitors, are basic elements and an integral part of the electrical distribution and the power transmission system. In addition to providing reactive power to the electrical system, this type of reactor has a wide field of application such as: short-circuit current limiter, Inrush current limiter (for capacitors and motors), harmonic filters, VAR compensation, Ripple reduction or smoothing, blocking coils, neutral grounding, switching transient damping, arc furnace, Flicker reduction, circuit tuning, charging balance etc. Depending on their function, the reactors are connected in series or in parallel with the network. The reactors can be connected directly to a network (shunt reactors, current limiters) or in conjunction with other basic components, such as power capacitors (harmonic filters, shunt capacitors, discharge current limiters, neutral ground). Dry-type air core reactors can be installed at any industrial plant, distribution or transmission voltage level and can range from a few amps to tens of thousands of amps and short-circuit current levels of up to hundreds of numbers of amps. Due to the wide application of the dry-type air-core reactor in the electrical power system, the cost considerations related to the losses inherent in the winding and the induced losses has fundamental importance in the design of the equipment design and in the measurements of routines performed during the process manufacturing. This dissertation aims to present a methodology to perform a measurement of the total losses (in the windings) using an Infrared Thermography in reactors with a dry-type air-core composed of a single cylinder. By making a comparison between the project carried out, measured and by the proposed methodology, it will be possible to carry out an evaluation of the work carried out with confirmation of good results.

23
  • MAISE NATALIA SOARES DA SILVA
  • Electroenergetic Analysis of Solar Photovoltaic Distributed Generation in Sao Tome and Principe.

  • Leader : PAULO FERNANDO RIBEIRO
  • MEMBRES DE LA BANQUE :
  • ANTONIO CARLOS ZAMBRONI DE SOUZA
  • BENEDITO DONIZETI BONATTO
  • FERNANDO NUNES BELCHIOR
  • PAULO FERNANDO RIBEIRO
  • Data: 2 déc. 2020


  • Afficher le Résumé
  • This work presents an analysis of the insertion of distributed solar photovoltaic generation in the National Electrical System of São Tomé and Príncipe. The study evaluates technical and economic aspects of viability using computational tools for this. The PVsyst software is used in the technical feasibility analysis of a 1MWp photovoltaic mini-generation system, based on the performance coefficient PR. The projected system has a nominal capacity to supply 882kW with a performance ratio of 80.47 %. In the economic viability analysis, the photovoltaic mini-generation system presented a 12-year return on investment, a calculated IRR equal to 6 % and, being greater than the defined value of MARR, the investment was considered economically viable. The simplified analysis of the aggregation of multiple sources of harmonic current, evaluates the insertion of three mini-generation systems to the existing network. The modeling and simulation is related to the MATLAB/
    Simulink package, returning the THD values and individual distortions, in addition
    to the results of the sum methods. In the simulation, the individual distortion values are similar to the values of the arithmetic method, except for the SE1 bus current, which presents an unexpected cancellation of harmonic orders 5 and 7. The economic feasibility analysis of distributed photovoltaic microgeneration systems is performed using HOMER Pro software, with the country’s energy tariffs as sensitivity variables. The results of this analysis show that the acquisition of photovoltaic systems is not feasible only for residential consumers with a tariff equal to 0.08US$/kWh. The viability of distributed microgeneration systems presents itself as an opportunity to reduce costs with thermal generation, bringing socioeconomic development to the country.

24
  • JANAINA MIRSES DE SOUSA CRUZ COSTA
  • Measurement of the Power Transformers Saturation Curve at from the Energization Current and Voltage.

  • Leader : LUIZ EDUARDO BORGES DA SILVA
  • MEMBRES DE LA BANQUE :
  • CLAUDIO FERREIRA
  • LUIZ EDUARDO BORGES DA SILVA
  • MATEUS DUARTE TEIXEIRA
  • WILSON CÉSAR SANT`ANA
  • Data: 4 déc. 2020


  • Afficher le Résumé
  • The computational models developed to represent the electrical equipment and transmission lines that are part of a given power system depend on the prior knowledge of the parameters necessary to reproduce the electrical phenomenon of interest. For the studies of electromagnetic transients that involve the energization of power transformers, as well as for the reproduction of transient phenomena that are influenced by the nonlinear behavior of these equipment, it is necessary to model accurately, besides the electrical parameters and type of connection of its windings, the saturation curve of the transformer in question. To carry out these parameters, it is necessary to carry out laboratory tests. However, for transformers of high voltage and power levels, the saturation characteristics of the magnetic material are usually obtained through calculations and estimates, since the laboratories do not usually have sufficient electrical power to bring the transformer to the appropriate saturation levels, which can lead to inaccuracies.
    In view of the concern to increase safety in the operational decisions made from simulation results of electromagnetic transient studies, Chesf identified the need to develop a methodology that allows the measurement of the saturation curve of its transformers in order to measure the curves supplied by manufacturers and obtain accurate models of power transformers in ATP_EMTP format.
    Thus, a measuring device and software were developed that allow the analysis of the transformer magnetization characteristics in operation in the electric system, whose chosen methodology is based on the inrush current waveforms of the respective transformer. The validation of the methodology was done by comparing the waveforms of the electric quantities of interest, obtained through field records, with those obtained in the computational simulations, using the STC model of the ATP, where the saturation curves raised by the application of the developed technique and that reported by the manufacturer.
    The obtained results showed that the methodology used is robust and can be applied from the waveform records obtained not only by the developed measuring device but also from any oscillography, including those Oscillography Network.

25
  • RAFAEL DE SOUZA SALLES
  • The Use of Advanced Signal Processing and Deep Learning for Pattern Recognition in Integrated Metrics of Quality Performance: A Smart Grid Application

  • Leader : BENEDITO ISAIAS LIMA FULY
  • MEMBRES DE LA BANQUE :
  • BENEDITO ISAIAS LIMA FULY
  • CAIRO LUCIO NASCIMENTO JUNIOR
  • CARLOS AUGUSTO DUQUE
  • GISCARD FRANCIMEIRE CINTRA VELOSO
  • GUILHERME SOUSA BASTOS
  • PAULO FERNANDO RIBEIRO
  • Data: 4 déc. 2020


  • Afficher le Résumé
  • Power quality (PQ) is not a new theme, but it should not be neglected in any way, as its performance parameters will reveal problems in the adequacy between the consumer equipment and the electrical grid. With the ongoing transformations in electrical power systems, characterized by the high penetration of renewable energy sources, the massive insertion of components based on power electronics in the network, and the decentralization of generation, these issues are becoming increasingly important. In Smart Grids, solutions are sought for more advanced solutions to solve PQ disturbances problems. Advanced signal processing plays an essential role in dealing with the network and supporting various applications within this context and Artificial Intelligence (AI), which has gained significant prominence to feed applications with innovative solutions in several areas. This research investigates the use of advanced signal processing and Deep Learning techniques for pattern recognition and classification of signals with PQ disorders. For this purpose, the Continuous Wavelet Transform with a filter bank is used to generate 2-D images with the time-frequency representation from signals with voltage disturbances. The work aims to use Convolutional Neural Networks (CNN) to classify this data according to the images' distortion. In this implementation of AI, specific stages of design, training, validation, and testing were carried out for a model elaborated by the case file and a knowledge transfer technique with the pre-trained networks SqueezeNet, GoogleNet, and ResNet-50. The work was developed in the MATLAB/Simulink software, all signal processing stages, CNN design, simulation, and the investigated data generation. All steps have their objectives fulfilled, culminating in the excellent execution and development of the research. The results sought high precision for CNN de Scratch and ResNet-50 in classify the test set. The other two models obtained not-so-high accuracy, and the results are consistent when compared with different methodologies. Considerations about the results were pointed out. Finally, some conclusions were established and a philosophical reflection on the role of AI and advanced signal processing in electrical power systems.

26
  • EVANDRO MARCOS VACILOTO FILHO
  • Methodology For Mitigation Of Interferences In The Protection System Of Capacitor Banks In Medium And High Voltage

  • Leader : LUIZ EDUARDO BORGES DA SILVA
  • MEMBRES DE LA BANQUE :
  • CARLOS HENRIQUE DA SILVA
  • LUIZ EDUARDO BORGES DA SILVA
  • ROBSON BAUWELZ GONZATTI
  • RONALDO ROSSI
  • Data: 7 déc. 2020


  • Afficher le Résumé
  • There are many types of protection for capacitor banks, like simple star, double star and H bridge. Burning of capacitive elements results in actuation of protection, due to variations in unbalance voltage and unbalance current previously set in the relay.But not only internal failures can cause sensibilization of protection, external system interferences cause variation of impedance between phases of equipment, resulting in false operation of protection system.
    Capacitance of capacitor units is a characteristic intrinsically linked to geometry of elements that composes the capacitor, but it varies with ambient temperature. Therefore, large capacitor banks when exposed to non-uniform shading present variation of capacitance and, as consequence, variations in unbalance voltage and unbalance current. The phenomenon of non-uniform shading can be observed mainly in Static Var Compensation (SVC) and Fixed Series Compensators (FSC), basically because of the size of its capacitor columns that favors partial shading of capacitor units.
    This study presents several aspects of balancing of capacitor banks, as well as clarifications about interference of external factors in the detection of failures of capacitor units. The simple geographical position of the capacitor bank can result in constant operational disturbances and, as consequence, increase of financial cost linked to unavailability, team displacement/mobilization and unnecessary repairs. Therefore, the results obtained in this study will help detecting interferences in the protection system of the capacitor bank, as well as alternatives to reduce external influence in the protection system. It will also analyze the principal factors impacting in the natural unbalance if the capacitor bank, increasing equipment reliability and operability of the equipment of reactive power compensation.

27
  • PAULO HENRIQUE VIEIRA SOARES
  • Proposed methodology for applying the GOOSE protocol in control and protection of the electrical system

  • Leader : PAULO MARCIO DA SILVEIRA
  • MEMBRES DE LA BANQUE :
  • CARLOS ALBERTO VILLEGAS GUERRERO
  • Eduardo Lorenzetti Pellini
  • FREDERICO OLIVEIRA PASSOS
  • PAULO MARCIO DA SILVEIRA
  • Data: 10 déc. 2020


  • Afficher le Résumé
  • The protection philosophy of the electric power system has been under great changes due to the evolution of numeric relays, the IEC61850 standard and the arrival of the digital substation (or 4.0) concept. Along with those changes, it also presents the dilemma of evolving without losing dependability on the traditional protection schemes and exploiting the ever-closer inherent benefits of technology. This dissertation work proposes the definition of the methodology to be followed and the implementation of GOOSE messages in protection schemes and substation control based on the IEC 61850 norm.

    The methodology is presented following the considerations of the IEC 61850 norm and the internal engineering definitions of a large company in Itabira/MG, which has more than 10 years of experience in the application of the GOOSE protocol to protection and control. The work analysis of the configuration software of six models of protection relays from three big IED manufacturers is performed in order to ensure a broader understanding about the specificities of each device. A network traffic analysis software is employed to validate the benefits of the proposed method. Features for GOOSE communication tests and remote monitoring of the integrity of the communication via supervisory system on
    the protection scheme are presented.

    To certify and validate the correct performance of the GOOSE messages exchanged between the IEDs following the presented methodology, tests based on the chapter 10 of the norm are proposed and executed for four distinct scenarios. A thousand tests are performed to each scenario adding up to four thousand tests to each IED and twenty-eight thousand tests to the seven IEDs group evaluated.

    The GOOSE message following the manufacturer’s default is compared with the GOOSE message according to the work methodology, clearly showing the advantages of the proposal, especially during troubleshooting at a substation. The methodology used in the definition of parameters and the proposal for testing and monitoring in the supervisory system of the integrity of GOOSE messages are new items that bring greater reliability to the protection and control system. It is noteworthy that the bench tests and the analysis of the results proved the good performance of the equipment for the tested scenarios.

28
  • FERNANDO FACHINI
  • A Comparison of Machine Learning Regression models for Critical Bus Voltage and Load mapping with regards to Max Reactive Power in PV buses.

  • Leader : BENEDITO ISAIAS LIMA FULY
  • MEMBRES DE LA BANQUE :
  • BENEDITO ISAIAS LIMA FULY
  • CAIRO LUCIO NASCIMENTO JUNIOR
  • GISCARD FRANCIMEIRE CINTRA VELOSO
  • GUILHERME SOUSA BASTOS
  • JOÃO ALBERTO PASSOS FILHO
  • Data: 10 déc. 2020


  • Afficher le Résumé
  • The aim of this master thesis is to compare voltage and system loading mapping capabilities of a variety of regression algorithms, such as Adaptive Network based Fuzzy Inference
    System (ANFIS), Artificial Neural Networks (ANN), K-Nearest Neighbors (KNN), Support Vector Regression (SVR), and Decision Tree (DT). A voltage sensitivity matrix is
    generated from the power flow Jacobian matrix for a loading scenario near the unstable point. Principal Component Analysis (PCA) is used to separate the system, close
    to the critical point, in order to group the buses into coherent voltage controlling areas.
    For different reactive power injection scenarios, we have different bus voltages that can
    be mapped by the aforementioned regression algorithms. The algorithms are trained with
    limited amounts of data, in order to establish a fair comparison between them. The present
    work shows that ANFIS and KNN have a better performance in critical voltage and load
    prediction when compared to the rest. The academic IEEE 14 and 118 bus systems are
    employed with all its limits considered, so the results may be reproduced.

29
  • REGIMAR MACIEL
  • FPGA Implementation of Interval Type-2 Fuzzy System Based on Nie-Tan Algorithm

  • Leader : ROBSON LUIZ MORENO
  • MEMBRES DE LA BANQUE :
  • EVALDO RENÓ FARIA CINTRA
  • PALOMA MARIA SILVA ROCHA RIZOL
  • ROBSON LUIZ MORENO
  • TALES CLEBER PIMENTA
  • Data: 15 déc. 2020


  • Afficher le Résumé
  • This work aims to propose and validate an architecture of an interval type-2 fuzzy logic systems implemented in FPGA, which meets real-time control applications, with serial processing in the inference mechanisms. This work presents the design and implementation of the circuits that make up the interval type-2 fuzzy logic systems, such as: the type-2 interval fuzzifier circuit (FOU); the minimum and maximum circuits that are used in the Mamdani inference mechanism (type-2); the circuit applied to the state machine that is used by the rules base and the circuit that processes the reducer-type and defuzzification operations based on the Nie-Tan algorithm. The hardware presented has two 8-bit inputs with four Gaussian pertinence functions for each input, sixteen rules, and an 8-bit output with seven pertinence functions. Finally, the results of the FPGA implementation are validated using the same interval type-2 fuzzy logic systems implemented in Matlab® with a Toolbox for type-2 fuzzy.

30
  • CASSIA AKEMI CASTRO KUKI
  • Forecasting energy prices methodology considering streamflow uncertainties

  • Leader : JOSE WANDERLEY MARANGON LIMA
  • MEMBRES DE LA BANQUE :
  • BENEDITO CLAUDIO DA SILVA
  • DOREL SOARES RAMOS
  • JOSE WANDERLEY MARANGON LIMA
  • MICHELLE SIMOES REBOITA
  • Data: 15 déc. 2020


  • Afficher le Résumé
  • The introduction of the electricity market at the Brazilian Power System makes the electricity price forecast an important area of research with many challenges to the market players because of its volatility. The identification of the main uncertainty sources is crucial to the development of the market. This knowledge helps in decision-making process related to energy contracting maximizing profits and reducing the risks to the agents. Thus, the aim of this study is forecasting electricity price from a computational chain composed of different interconnected models: CFSv2 climate model to forecast precipitation, MGB-IPH hydrological model to compute the inflows to reservoirs and energy programs currently in use in the Brazilian sector to define the price for three months ahead. The results show that, in general, the proposed methodology is able to predict and represent the streamflow behavior for the target operating weeks in the case study for June, July and August (JJA) 2020. This performance is justified by incorporating data from precipitation forecast to the hydrological model, improving the sensitivity of the streamflow forecasts. Streamflow forecasts are currently the variable with the greatest impact on the electricity price (PLD) that is calculated by the National Interconnected System (SIN). However, when analyzing the results obtained for the forecasted electricity price, the computational chain incorporating PREVIVAZ for the weekly streamflow forecasts presents error propagation along the simulation chain. The PREVIVAZ, used by the National System Operator (ONS), uses historical data and not the CFSv2 precipitation prediction. The different approaches are analyzed and conclusions about their uses in the middle office of traders are taken.

31
  • CLAUDIO PEREIRA DE OLIVEIRA
  • HIGH VOLTAGE DIRECT CURRENT AS AN ALTERNATIVE FOR DAMPING OF ELECTROMECHANICAL OSCILLATIONS IN ELECTRICAL POWER SYSTEMS - HVDC CONTROL ASPECTS

  • Leader : BENEDITO ISAIAS LIMA FULY
  • MEMBRES DE LA BANQUE :
  • ADRIANA APARECIDA DOS SANTOS IZIDORO
  • ANGELO JOSE JUNQUEIRA REZEK
  • BENEDITO ISAIAS LIMA FULY
  • JOSE CARLOS GRILO RODRIGUES
  • Data: 16 déc. 2020


  • Afficher le Résumé
  • There are several reasons for writing a document related to the high voltage direct current transmission system, highlighting the fast and precise controllability of the HVDC and the possibilities of their applications in order to contribute to the damping of electromechanical oscillations in the electric power system. This document addresses the main aspects of the HVDC control systems.
    After several years in various electrical systems in use around the world, is notorious the success related to these HVDC connections, the text aims to present the behavior in steady state and dynamic behavior of these systems, so that we can understand the minimum requirements for robust and precise control for a transmission systems based on the principle of current source converters (CSC), known commercially for classic converters.

32
  • ANA LUISA DO AMARAL BATISTA
  • Spread Effects of LED Lamps on Distribution Systems

  • Leader : JOSE MARIA DE CARVALHO FILHO
  • MEMBRES DE LA BANQUE :
  • FERNANDO NUNES BELCHIOR
  • JOSE EUGENIO LOPES DE ALMEIDA
  • JOSE MARIA DE CARVALHO FILHO
  • THIAGO CLE DE OLIVEIRA
  • Data: 17 déc. 2020


  • Afficher le Résumé
  • This work presents the results of an investigation of the impact of power quality disturbances in LED lighting technology. When existing such disturbances in the electrical system, they can cause damage to the most sensitive equipments.
    At the same time, the non-linearity feature of new lighting technologies may generate disturbances in the distribution system and consequently, cause power quality problems in the distribution system. In this scene, the widespread use of LED lamps and flooglights, in recent years, has become a concern for several worldwide’s researchers.
    In order to determine this cause-effect relationship between LED lighting and the distribution system, this work tested low power lamps, normally used in residential illumination and higher power lamps, used in industry and for public lighting.
    These lamps were tested in a laboratory setting, where it was possible to control the variables in order to determine the unique behavior of each technology studied. In addition, the new lighting technology’s impact on the power quality indicators in the distribution systems could be verified through measurements in establishment that have large quantities of LED lamps.

33
  • JOÃO PAULO DOS REIS
  • Use of the Economic Market Model “Optimized Tariff - Tarot” for Assessment of Sustainable Business Scenarios of Micro and Mini Shared Distributed Generation

  • Leader : BENEDITO DONIZETI BONATTO
  • MEMBRES DE LA BANQUE :
  • ANTONIO CARLOS ZAMBRONI DE SOUZA
  • BENEDITO DONIZETI BONATTO
  • FERNANDO NUNES BELCHIOR
  • Data: 18 déc. 2020


  • Afficher le Résumé
  • The accelerated expansion of micro and mini distributed generation (MMGD), associated with the net metering system (SCEE), have a negative impact on power distribution companies and consumers who do not have this type of technology. In recent years, Brazilian Electricity Agency – ANEEL has been seeking changes to Normative Resolution nº. 482 of 2012 in order to provide a more balanced and fair environment. However, the Agency's difficulty in achieving this result is clear. From this context and, aiming to contribute to regulatory improvements, but, exploring alternatives not yet discussed in the public debate environment promoted by the regulatory agency, this dissertation proposes, using the economic market model “TAROT – Optimized Tariff”, to evaluate business scenarios sustainable MMGD for the “Shared Generation” type - that is, this work isolates a specific type of MMGD and assesses sustainable business scenarios. The relevance, justification and contribution of this research lies in the search for sustainable alternatives for the development of MMGD and, at the same time, the electric energy distribution segment. To achieve this objective, extensive national and international research were carried out, choosing to evaluate business models implemented in other countries: a model based on the concept of “Solar Community” was chosen. Several modeling was carried out, based on real data from a utility, exploring different scenarios, the results of which were favorable to the implementation of this type of business in Brazil.

34
  • NEDSON JOAQUIM MAIA
  • A Low Power CMOS Operational Transconductance Amplifier with Improved CMRR

  • Leader : ROBSON LUIZ MORENO
  • MEMBRES DE LA BANQUE :
  • EVALDO RENÓ FARIA CINTRA
  • GABRIEL ANTONIO FANELLI DE SOUZA
  • ROBSON LUIZ MORENO
  • TALES CLEBER PIMENTA
  • Data: 18 déc. 2020


  • Afficher le Résumé
  • This work presents a topology of a low power Transconductance Operational Amplifier (OTA) for the compensation of Common Mode Rejection Ratio (CMRR), in which the transistors operate in the strong inversion mode. Initially, a theoretical review of the differential amplifier and OTA is presented. Then, an OTA architecture was proposed based on a symmetric differential amplifier structure with additional transistors in parallel to the input MOS transistors, in order to increase the CMRR rate, as well as the proposed compensation strategy. The OTA was designed using IBM 130 nm CMOS technology. Monte Carlo and Corner simulations were performed to analyze the compensation strategy and to obtain a more realistic assessment. The results obtained demonstrate that the proposed circuit for common mode control operates correctly, since the proposed OTA enabled common mode control in parallel, obtaining a CMRR of 87.34 dB and power consumption of 9.65 µW, validating its compatibility with low power circuits.

35
  • LUIZ FERNANDO RIBAS MONTEIRO
  • Determination of the operational conditions of Microgrids based on Neural Networks

  • Leader : LUIS HENRIQUE DE CARVALHO FERREIRA
  • MEMBRES DE LA BANQUE :
  • FELIPE OLIVEIRA E SILVA
  • FERNANDO HENRIQUE DUARTE GUARACY
  • LUIS HENRIQUE DE CARVALHO FERREIRA
  • Data: 18 déc. 2020


  • Afficher le Résumé
  • The increased insertion of renewable generation, mainly wind and solar, brings new challenges for the planning and operation of electric power systems due to its dependence on climatic conditions. In this perspective, this dissertation aims to propose a methodology based on Artificial Neural Networks (ANN) for pattern recognition and a self-organizing map to assist in the planning and operation of the power system. In this context, the operational conditions that can lead the system to breach of voltage limits can be identified, enabling corrective control actions to be carried out. In addition, the proposed approach is able to identify the specific unit responsible for driving the system to an unsatisfactory operating condition. For this, the methodology is tested in a microgrid represented by the modified unbalanced three-phase IEEE 34-bus system, considering the use of wind and solar generation. The data set of satisfactory and unsatisfactory operating conditions are obtained using the Monte Carlo simulation. For this purpose, the backward-forward scan power flow is employed. These data are then provided to ANNs for training, validation and testing. The results obtained indicate a robust methodology capable of assisting in decision making and determining control actions during the operation of the system with high insertion of renewables, thus avoiding overvoltages.

36
  • NÍCOLAS DE OLIVEIRA PEREZ WESTIN
  • Optimal Reclosers Allocation in Distribution Network considering Short-Duration Voltage Variations

  • Leader : JOSE MARIA DE CARVALHO FILHO
  • MEMBRES DE LA BANQUE :
  • JUAN CARLOS CEBRIAN AMASIFEN
  • CARLOS ALBERTO VILLEGAS GUERRERO
  • JOSE MARIA DE CARVALHO FILHO
  • THIAGO CLE DE OLIVEIRA
  • Data: 18 déc. 2020


  • Afficher le Résumé
  • Due to the constant evolution of society, with the fast technologies and processes modernization, energy dealerships suffer constant demands to improve their services, culminating in investments in their infrastructure, manpower and product quality. Studies are generally carried out to allocate protective devices to reduce pre-established service quality levels.
    Short-Duration Voltage Variations (VTCDs) are events that cause problems for the various dealerships’ consumers. As they have random occurrence, the capture of the associated parameters becomes dificult, due to the dificulty in having measurement equipment at different points in the network. In this scenario, methodologies for faults simulation are important to estimate the behavior of such variables.
    This master’s thesis proposes a methodology for reclosers placement in distribution systems when considering the voltage sags’ impacts in sensitive consumer.
    In order to estimate the various events, the performance of the State Enumeration Method and Monte Carlo Simulation, the most common short circuit simulation methodologies, were compared in a modifed IEEE test system, when monitoring four buses at different points in the network .
    This work presents the results obtained from the comparison between the short circuit simulation methodologies and their variables’ computational impacts. Monte Carlo Simulation is an effective and practical method to estimate events.
    The technique that provided the best cost-beneft was used to estimate the average voltage sags’ values, now in an modifed IEEE test system with double feeder, as input data to the optimization routine, via Genetic Algorithm, for the recloser placement. Real coordinated and selective adjustments were applied to verify the impact of the series installation of automatic reclosure devices.
    Also, the impacts arising from the optimal reclosers placement are presented. The adoption of real adjustments shows the differences imposed on the behaviors in the coordinated and selective philosophies adopted. The methodology proves to be robust to capture these peculiarities during optimization.

Thèses
1
  • ANDREIA APARECIDA DE CASTRO ALVES
  • Reconfigurable Antenna Array for 5G using Metamaterials

  • Leader : DANILO HENRIQUE SPADOTI
  • MEMBRES DE LA BANQUE :
  • ARISMAR CERQUEIRA SODRÉ JUNIOR
  • DANILO HENRIQUE SPADOTI
  • ILDEFONSO BIANCHI
  • JOSE ANTONIO JUSTINO RIBEIRO
  • LEONARDO LORENZO BRAVO ROGER
  • Data: 14 févr. 2020


  • Afficher le Résumé
  • The handheld devices for the fifth-generation (5G) of mobile communications will support
    diverse services using different frequency bands, including the Second Frequency Range

    (FR2), from 24.25 GHz to 52.60 GHz. This millimeter-wave (mm-waves) bandwidth pro-
    vides high data rates, i.e. ≈2.15 Gbit/s for downlink and ≈2.37 Mbit/s up-link, however,

    the characteristics of the channels, devices manufacturing, and the high free space losses
    are some of the limiting factors of this frequency range. The network effectiveness will
    then depend directly on the use of high-performance antennas, reconfigurable devices,
    reduced costs, among other aspects. Taking advantage of the needs of 5G systems, this
    thesis presents a low-cost (initial prototype worth ≈250 reais), lightweight antenna array
    with reconfigurable two-dimensional beam steering (azimuth and elevation) to operate in

    millimeter waves. The main innovation is the antenna feed network based on metamate-
    rials with low insertion loss, linearity operation, and reduced stage number. This network

    performs the beam steering through phase reconfiguration without interfering with the
    antenna array performance. Additionally, a parasitic patches technique was applied in
    order to improve gain and bandwidth. The project methodology is based on analytical
    calculations and numerical simulations were carried out using the software Ansys HFSS.
    The array performance has been analyzed in terms of the mutual coupling to evaluate its
    possible application in a multi-antennas system. The approach has a total size of 6×6 cm,
    compact enough to operate inside a mobile phone. All pre-set design requirements were

    achieved, resulting in an antenna array gain of 12.5 dBi, 2.8 GHz bandwidth, reconfig-
    urability of 20∘

    , sidelobe level below 10 dB and mutual coupling lower than -50 dB.

2
  • POLIANE AIRES TEIXEIRA

  • Polarization splitter with arbitrary geometries through quasi-conformal transformation optics

  • Leader : MATEUS AUGUSTO FAUSTINO CHAIB JUNQUEIRA
  • MEMBRES DE LA BANQUE :
  • DANILO HENRIQUE SPADOTI
  • EDUARDO HENRIQUE SILVA BITTENCOURT
  • JOSE ANTONIO JUSTINO RIBEIRO
  • LUCIA AKEMI MIYAZATO SAITO
  • MATEUS AUGUSTO FAUSTINO CHAIB JUNQUEIRA
  • SUELENE SILVA MAMMANA
  • Data: 4 mars 2020


  • Afficher le Résumé
  • This work presents a study about polarization beam splitters with the two-dimensional

    quasi-conformal transformation optics technique application. The use of the tranforma-
    tion optics allows the obtaining of arbitrary waveguide geometries exemplified by two

    compact models of splitters, one represented by symmetrical waveguides and the other
    by asymmetric guides with dimensions of 64 μm2 and 110 μm2

    , respectively. Simulations
    results demonstrated that the devices exhibit maximum insertion loss of 0.22 dB and
    extinction rate above 40 dB in C band. The splitters performance was evaluated in the
    fundamental, third and fifth order modes in order to increase the possibilities of the device
    application. The splitter behavior was also analyzed in function of a three-dimensional
    geometry where the extinction rate and insertion loss values are close to found for the
    two-dimensional cases. Usually, the use of the transformation optics in the design of
    media with desired functionalities results in complex material characteristics, generally
    including inhomogeneous and anisotropic permittivity and permeability tensors. Thus,

    it is proposed, even as a contribution of this thesis the quasi-conformal mapping appli-
    cation in the transformation optics to minimize the medium anisotropy. The use of the

    quasi-conformal transformation optics in the developed structures allows the elimination
    of the magnetic response and the permittivity tensor becomes uniaxial enabling the use
    of uniaxial materials to device manufacture. Also thinking about facilitating the splitter
    implementation, its creation was evaluated through the quasi-conformal transformation
    optics application in only one of the polarizations, obtaining a device with dimensions
    equal to 82 μm2

    . The minimum and maximum refractive index values of the structures
    proposed after transformation were 1.05 and 3.28, being within the limits provided by
    lithium niobate. Furthermore, this strategy does not change the boundary conditions
    with the purpose of avoiding reflections in the boundaries of the medium and ensuring
    the functionality of the device as defined by the initial coordinate transformation.

3
  • LUCAS FREDERICO JARDIM MELONI

  • Single-Phase Series active power filter with LC ressonant filter for harmonic voltage reduction

  • Leader : ANGELO JOSE JUNQUEIRA REZEK
  • MEMBRES DE LA BANQUE :
  • ADRIANA APARECIDA DOS SANTOS IZIDORO
  • ANGELO JOSE JUNQUEIRA REZEK
  • BENEDITO DONIZETI BONATTO
  • DEMERCIL DE SOUZA OLIVEIRA JUNIOR
  • ENIO ROBERTO RIBEIRO
  • LUIS HENRIQUE DE CARVALHO FERREIRA
  • Data: 6 mars 2020


  • Afficher le Résumé
  • Series active filters are able to correct the harmonic voltage distortion in sensitive loads,
    such induction motors and transformers, allowing their proper operation. These active filters
    employ converters connected between the power source and loads, that receive the entire circuit
    current and being stricken by inner losses. This thesis presents a series active system formed by
    an single-phase converter operating with a tuned passive LC filter. The LC filter will provide a
    partial current bypass, reducing the converter losses. Initially an small signal model is obtained,
    which describes converter operation with bipolar and unipolar PWM modulations. By these

    model analysis, selection criteria and desirable conditions will be raised to achieve the maxi-
    mum current deviation. After that, the design procedure for output voltage and current control

    systems will be detailed. Each criterion will be evaluated through computer simulations, which
    will illustrate different operating conditions of the active filtering system. Finally, the prototype
    building aspects will be show, in addition with experimental results.

4
  • VINICIUS ZIMMERMANN SILVA
  • Dynamic Emulation and Analysis of Synchronous and Induction Generators in Parallel Operation Mode in an

    Isolated Electric System

  • Leader : ANGELO JOSE JUNQUEIRA REZEK
  • MEMBRES DE LA BANQUE :
  • JOSE CARLOS GRILO RODRIGUES
  • RICARDO ELIAS CAETANO
  • ANGELO JOSE JUNQUEIRA REZEK
  • JOSE CARLOS DE OLIVEIRA
  • NERY DE OLIVEIRA JUNIOR
  • Data: 24 avr. 2020


  • Afficher le Résumé
  • This work aims to present new contributions for electrical machines application studies,
    mainly about analysis of induction and synchronous generators in parallel operation mode,
    including studies of generation and load transients and contingencies against undesirable
    effects of frequency increasing. Then, in summary, the main topics presented in this work
    are: an analysis of induction and synchronous generators in parallel operation mode,
    studies of load and generation transients and, finally, studies of increasing frequency for
    this cited generator topology, the causes of increasing frequency and alternatives to control
    these effects. All of this main subject are supported by appendixes that contributes with
    practical and original studies related to each subsystem that is part of main experiments
    such as: (i) voltage and current regulators for DC machines, (ii) firing circuit, (iii) voltage
    regulators to synchronous generators, (iv) four-quadrant Driven System for DC Machine
    and (v) analogical and digital control boards.

5
  • RAMON MAIA BORGES
  • Analog Radio over Fiber Solutions for Multi-band 5G Systems

  • Leader : DANILO HENRIQUE SPADOTI
  • MEMBRES DE LA BANQUE :
  • ARISMAR CERQUEIRA SODRÉ JUNIOR
  • DANILO HENRIQUE SPADOTI
  • JOSE ANTONIO JUSTINO RIBEIRO
  • MARCELO EDUARDO VIEIRA SEGATTO
  • MURILO ARAUJO ROMERO
  • Data: 22 juil. 2020


  • Afficher le Résumé
  • This study presents radio over fiber (RoF) solutions for the fifth-generation (5G) of wireless networks. After the state of the art and a technical background review, four main contributions are reported. The first one is proposing and investigating a RoF technique based on a dual-drive Mach-Zehnder modulator (DD-MZM) for multi-band mobile fronthauls, in which two radiofrequency (RF) signals in the predicted 5G bands individually feed an arm of the optical modulator. Experimental results demonstrate the approach enhances the RF interference mitigation and can prevail over traditional methods.
    The second contribution comprises the integration of a 5G transceiver, previously developed by our group, in a passive optical network (PON) using RoF technology and wavelength division multiplexing (WDM) overlay. The proposed architecture innovates by employing DD-MZM and enables to simultaneously transport baseband and 5G candidate RF signals in the same PON infrastructure. The proof-of-concept includes the transmission of a generalized frequency division multiplexing (GFDM) signal generated by the 5G transceiver in the 700 MHz band, a 26 GHz digitally modulated signal as a millimeter-waves 5G band, and a baseband signal from an gigabit PON (GPON). Experimental results demonstrate the 5G transceiver digital performance when using RoF technology for distributing the GFDM signal, as well as Gbit/s throughput at 26 GHz.
    The third contribution is the implementation of a flexible-waveform and multi-application fiber-wireless (FiWi) system toward 5G. Such system includes the FiWi transmission of the GFDM and filtered orthogonal frequency division multiplexing (F OFDM) signals at 788 MHz, toward long-range cells for remote or rural mobile access, as well as the recently launched 5G NR standard in microwave and mm-waves, aiming enhanced mobile broadband indoor and outdoor applications. Digital signal processing (DSP) is used for selecting the waveform and linearizing the RoF link. Experimental results demonstrate the suitability of the proposed solution to address 5G scenarios and requirements, besides the applicability of using existent fiber-to-the-home (FTTH) networks from Internet service providers for implementing 5G systems.
    Finally, the fourth contribution is the implementation of a multi-band 5G NR system with photonic-assisted RF amplification (PAA). The approach takes advantage of a novel PAA technique, based on RoF technology and four-wave mixing effect, that allows straightforward integration to the transport networks. Experimental results demonstrate uniform and stable 15 dB wideband gain for Long Term Evolution (LTE) and three 5G signals, distributed in the frequency range from 780 MHz to 26 GHz and coexisting in the mobile fronthaul. The obtained digital performance has efficiently met the Third-Generation Partnership Project (3GPP) requirements, demonstrating the applicability of the proposed approach for using fiber-optic links to distribute and jointly amplify LTE and 5G signals in the optical domain.

6
  • FILIPE PEREZ
  • Control of AC/DC Microgrids with Renewables in the Context of Smart Grids Including Ancillary Services and Electric Mobility

  • Leader : PAULO FERNANDO RIBEIRO
  • MEMBRES DE LA BANQUE :
  • ANTONIO CARLOS ZAMBRONI DE SOUZA
  • BENEDITO DONIZETI BONATTO
  • DIDIER GEORGES
  • FRANÇOISE LAMNABHI-LAGARRIGUI
  • GLAUCO NERY TARANTO
  • PAULO FERNANDO RIBEIRO
  • PEDRO MACHADO DE ALMEIDA
  • WILLIAM PASILLAS-LEPINE
  • Data: 28 sept. 2020


  • Afficher le Résumé
  • Microgrids are a very good solution for current problems raised by the constant growth of load demand and high penetration of renewable energy sources, that results in grid modernization through “Smart-Grids” concept. The impact of distributed energy sources based on power electronics is an important concern for power systems, where natural frequency regulation for the system is hindered because of inertia reduction. In this context, Direct Current (DC) grids are considered a relevant solution, since the DC nature of power electronic devices bring technological and economical advantages compared to Alternative Current (AC). The thesis proposes the design and control of a hybrid AC/DC Microgrid to integrate different renewable sources, including solar power and braking energy recovery from trains, to energy storage systems as batteries and supercapacitors and to loads like electric vehicles or another grids (either AC or DC), for reliable operation and stability. The stabilization of the Microgrid buses' voltages and the provision of ancillary services is assured by the proposed control strategy, where a rigorous stability study is made. A low-level distributed nonlinear controller, based on “System-of-Systems” approach is developed for proper operation of the whole Microgrid. A supercapacitor is applied to deal with transients, balancing the DC bus of the Microgrid and absorbing the energy injected by intermittent and possibly strong energy sources as energy recovery from the braking of trains and subways, while the battery realizes the power flow in long term. Dynamical feedback control based on singular perturbation analysis is developed for supercapacitor and train. A Lyapunov function is built considering the interconnected devices of the Microgrid to ensure the stability of the whole system. Simulations highlight the performance of the proposed control with parametric robustness tests and a comparison with traditional linear controller. The Virtual Synchronous Machine (VSM) approach is implemented in the Microgrid for power sharing and frequency stability improvement. An adaptive virtual inertia is proposed, then the inertia constant becomes a system's state variable that can be designed to improve frequency stability and inertial support, where stability analysis is carried out. Therefore, the VSM is the link between DC and AC side of the Microgrid, regarding the available power in DC grid, applied for ancillary services in the AC Microgrid. Simulation results show the effectiveness of the proposed adaptive inertia, where a comparison with droop and standard control techniques is conducted.

7
  • GABRIEL LOBÃO VASCONCELOS FRÉ
  • Graphene-based Terahertz Modulator in Low Loss Slotted Waveguide

  • Leader : DANILO HENRIQUE SPADOTI
  • MEMBRES DE LA BANQUE :
  • JHONATTAN CÓRDOBA RAMÍREZ
  • SAMUEL BARALDI MAFRA
  • DANILO HENRIQUE SPADOTI
  • JOSE ANTONIO JUSTINO RIBEIRO
  • LUCIA AKEMI MIYAZATO SAITO
  • ROBERTO SHIGUERU NOBUYASU JUNIOR
  • Data: 6 nov. 2020


  • Afficher le Résumé
  • This work presents an alternative THz-modulator, using a low-loss slotted waveguide. The interaction between THz-signal and the optical carrier wave is performed along the modulator length, which is substantially greater than the conventional bi-dimension modulators. Two different structures were studied in order to obtain the modulator: a silicon based photo-excited waveguide, and a graphene based electrically controlled waveguide. The modulation depth is greater than 10 dB with a 200 GHz of bandwidth, enabling the device to telecommunication operations in THz frequencies. Moreover, this works results in an integrated silicon on insulator compatible design.

8
  • JULIANA RIBAS MONTEIRO
  • Allocation of Renewable Sources in Islanded Grids

  • Leader : ANTONIO CARLOS ZAMBRONI DE SOUZA
  • MEMBRES DE LA BANQUE :
  • ANTONIO CARLOS ZAMBRONI DE SOUZA
  • ELIANE VALENCA NASCIMENTO DE LORENCI
  • GLAUCO NERY TARANTO
  • JULIO CESAR STACCHINI DE SOUZA
  • PEDRO PAULO BALESTRASSI
  • Data: 6 nov. 2020


  • Afficher le Résumé
  • New opportunities enabled by renewable mobile power stations (RMPSs), in association with microgrids (MGs) ability to operate islanded to the main grid, presents a likely solution to ensure power system novel reliability requirements in face of the increasing number of severe disruptive events.
    In this perspective, this work proposes a novel intelligent RMPS allocation method to support MGs during scheduled islanded operation. In this operating mode, the isolated operation of a MG is beforehand planned to mitigate the effects caused by possible predictable contingencies, e.g. weather-related events, as well as programmed maintenance. For this, first a novel energy management strategy (EMS) based on dynamic programming specifically designed for MG scheduled islanded operation is proposed. Next, a particle swarm optimization (PSO) method modified to ensure a continuous search space in the face of discrete load shedding policies is developed to determine the adequate allocation of RMPS.
    The proposed method is simulated for different scenarios for a MG system considering local distributed generation capacity, electric vehicles’ penetration, load shedding based on priority groups, as well as technical and operational limits. The obtained results showcase the proposed approach's ability to meaningfully improve MG service capacity during scheduled islanded operation.

9
  • FRANCO BASSI ROCHA
  • Short-term load forecast using combination of artificial neural networks and design of experiments

  • Leader : PEDRO PAULO BALESTRASSI
  • MEMBRES DE LA BANQUE :
  • ANDERSON PAULO DE PAIVA
  • ANTONIO CARLOS ZAMBRONI DE SOUZA
  • JOSE PAULO CARVALHO DOS SANTOS
  • PAULO FERNANDO RIBEIRO
  • PEDRO PAULO BALESTRASSI
  • WESLEY VIEIRA DA SILVA
  • Data: 4 déc. 2020


  • Afficher le Résumé
  • This work proposes a new approach to short-term load forecast for power distribution substations using the artificial neural network ensemble. In this sense, the main objective of this approach is to make predictions for the same time series using different tools that are competent for this type of problem and then combine the solutions, obtaining a better solution compared to those tools used individually. For the construction of the ensemble, the experimental planning methodology (DOE) was used initially to identify the influence of 6 factors related the parameterization of the ANN and from the desirability optimization method to obtain a parameterization to determine the architecture of the neural networks
    that formed the ensemble . Then, the normal intersection optimization method (NBI) combined with the technique of exploratory factor analysis (based on mixture design of experiments) was used to establish a set of optimal Pareto solutions for combining the outputs produced by neural networks, forming the output of the ensemble. As a criterion of choice, the maximum ratio between Shannon’s entropy and global percentage error was used and based on the 72 out of sample data the ensemble of artificial neural networks presented better results compared to each individual network.

10
  • LETICIA DOS SANTOS BENSO MACIEL
  • Avaliação de Políticas Públicas para Tarifa Social Justa de Energia Elétrica no Brasil por meio de modelo de mercado econômico

  • Leader : BENEDITO DONIZETI BONATTO
  • MEMBRES DE LA BANQUE :
  • ANDERSON RODRIGO DE QUEIROZ
  • BENEDITO DONIZETI BONATTO
  • FERNANDO NUNES BELCHIOR
  • MOISES DINIZ VASSALLO
  • VICTOR EDUARDO DE MELLO VALERIO
  • Data: 4 déc. 2020


  • Afficher le Résumé
  • Evaluating Public Policies for Fair Social Tariff of Electricity in Brazil using an Economic Market Model

11
  • PRISCILA MAYARA DUARTE DOS SANTOS
  • Locational Pricing in Electricity Distribution Systems considering the Insertion of Distributed Generation and Electric Vehicles

  • Leader : ANTONIO CARLOS ZAMBRONI DE SOUZA
  • MEMBRES DE LA BANQUE :
  • ANTONIO CARLOS ZAMBRONI DE SOUZA
  • BENEDITO DONIZETI BONATTO
  • ELIANE VALENCA NASCIMENTO DE LORENCI
  • MADSON CORTES DE ALMEIDA
  • PEDRO PAULO BALESTRASSI
  • WALMIR FREITAS FILHO
  • Data: 7 déc. 2020


  • Afficher le Résumé
  • Electric energy is a product sold through its market. Each kWh of energy produced directly impacts the social development of a given region. It is necessary for satisfactory economic growth, that the energy supplied in an area is the result of a process of production, transmission, and balanced distribution, especially about costs. In this process of equilibrium, there is the wish of the sector for a structure where the costs are compensated, and the expenses do not exceed the expectations of the consumers. The sector is divided by level. Each level is responsible for the recovery of the investment for the supply of energy. Thus, the system expects that the remuneration for investments at the distribution level will be compensated as an economic signal at the same level. This signaling is given a distribution tariff, which will compensate the concessionaire for all service provision the loads and distributed systems connected on the grid. This work presents a form of compensation costs of the distribution network using the locational pricing and discusses how the sector can regulate this type of approach. The locational pricing is given by the division of responsibility on cost recovery at the level of distribution. The signal is a locational tariff applied to consumers, passive or active. A portion of the locational tariff is attributed to distributed systems according to the use he makes of the network at that level. The model adopted consists of the formulation of two-step calculations. The portion relating to prices on capacity used by an inserted element in the network, and the portion that describes the price on the unused capacity of an element. It is based on the Long Term Incremental cost method, which is nothing more than a form of marginal pricing of electricity. The tariff signal is the result of the application of the incremental cost. The objective is to present a price signal for a microgrid in the context of smart grids, where there will be electric vehicles acting as generators. Besides, it seeks to indicate through a nodal and zonal formulation of a given system how loads and generators can benefit from this kind of situation and how they can influence the type of market and pricing adopted in an area. The analysis considers the power flow on the IEEE 34 bus test system and consists of the five scenarios.

12
  • JONATTAN EMANUEL SARMIENTO
  • A direct method to find low voltage solutions in the power flow problem

  • Leader : ANTONIO CARLOS ZAMBRONI DE SOUZA
  • MEMBRES DE LA BANQUE :
  • AHDA PIONKOSKI GRILO PAVANI
  • MIGUEL CASTILLA FERNANDEZ
  • ANTONIO CARLOS ZAMBRONI DE SOUZA
  • ELIANE VALENCA NASCIMENTO DE LORENCI
  • PEDRO PAULO BALESTRASSI
  • Data: 8 déc. 2020


  • Afficher le Résumé
  • In the current context, Distributed Generators are progressively increasing their importance in the operation of distribution systems, and, consequently, the study of voltage stability increases their importance in these systems as well. Since Low-voltage Solutions (LVS) of the power flow equations are an important information for voltage stability analyzes, the need arises for a specialized method to locate LVS in distribution systems. This need can be divided into two sub-problems: first, the development of a power flow method with the capability to calculate LVS in distribution systems, and lastly, the specialization of this power flow method to locate LVS. In this work, it is proposed to solve both sub-problems. For the first, a three-phase power flow method for distribution systems with the capability to calculate LVS is proposed, which is based on an innovative formulation written in complex numbers. This formulation is solved by Newton’s method using Wirtinger calculus. For the second sub-problem, three formulations are proposed to locate LVS directly, called: basic formulation, alternative basic, and SBT-RCF formulation. The three are based on a characteristic of the generalized eigenvalues of the power flow, which indicates that when a normal operating solution occurs, all eigenvalues are complex, and when an LVS occurs, there is a pair of pure real eigenvalues. In the convergence analysis of the proposals, the power flow method has better computational performance when compared to a typical method of distribution systems, the backward-forward sweep method. In addition, the proposed method can converge in an LVS, being an essential feature in analysis of voltage stability. In relation to formulations to locate LVS, Newton's method fails to try to solve the basic formulation due to the poor global convergence of this method in this formulation. In the alternative basic formulation, Newton's method shows slight improvement, however, false convergences can happen due to the formulation being based on the gradient of a merit function. Nevertheless, for the SBT-RCF formulation, an equivalent optimization problem was developed, in which a relaxation of the equation was performed. The problem was solved using the interior points method, presenting convergence characteristics superior to Newton's method when solving the previous formulations, being able to calculate LVS in systems of 2, 4, 34 and 123 buses without problems.

13
  • JOÃO ALVES DA SILVA NETO
  • Study of Voltage Stability in Transmission Systems and Microgrids Using the Energy Function Method

  • Leader : ANTONIO CARLOS ZAMBRONI DE SOUZA
  • MEMBRES DE LA BANQUE :
  • TATIANA MARIANO LESSA DE ASSIS
  • ADRIANO BATISTA DE ALMEIDA
  • ANTONIO CARLOS ZAMBRONI DE SOUZA
  • BENEDITO DONIZETI BONATTO
  • ELIANE VALENCA NASCIMENTO DE LORENCI
  • JOAO GUILHERME DE CARVALHO COSTA
  • Data: 9 déc. 2020


  • Afficher le Résumé
  • The growing concern related to the depletion of fossil fuels, the environmental effects of greenhouse gas emissions, and the low efficiency in transmitting large blocks of energy over long distances gave support to a new concept of energy systems, the microgrids. Thus, among the studies needed for these new systems, the voltage stability is cited. Therefore, this thesis proposes the analysis of static voltage stability in microgrids (islanded or isolated mode) and in transmission systems (considering the transmission-microgrid coupling) using the classical energy function method. The energy function allows the direct stability evaluation of the system operating points, taking into account the variation of loads, the intermittence of the photovoltaic sources and the charging/discharging of energy storage systems under pre-defined conditions. In addition, the auxiliary energy function is used to rank less robust buses in the microgrids and transmission systems. For microgrids, the auxiliary energy function indicates which buses are candidates for the insertion of intermittent sources. As for transmission systems, the auxiliary energy function indicates which microgrids connected to the main system are candidates for load shedding. Finally, considering the microgrid operation in islanded mode, it is evaluated which configuration is the most appropriate to supply critical loads within quality standards in the longest possible time. The results show the effectiveness of the voltage stability assessment using the energy function and the improvement of the energy-based voltage security index when using the auxiliary function technique to allocate intermittent sources and load shedding. The proposed methodologies are validated in a modified IEEE 37 node test feeder and IEEE 30 bus.

14
  • THAIS PRESSES MENDES
  • Theories on Dynamic Phasors Obtained from Integral Transforms

  • Leader : ANTONIO CARLOS ZAMBRONI DE SOUZA
  • MEMBRES DE LA BANQUE :
  • LUIS FERNANDO COSTA ALBERTO
  • ANTONIO CARLOS ZAMBRONI DE SOUZA
  • DENIS DE CARVALHO BRAGA
  • ELIANE VALENCA NASCIMENTO DE LORENCI
  • GLAUCO NERY TARANTO
  • LUCAS RUIZ DOS SANTOS
  • LUIS FERNANDO DE OSORIO MELLO
  • Data: 17 déc. 2020


  • Afficher le Résumé
  • The Classical Phasor Theory goes back to the pioneer work of Charles Proteus Steinmetz in the study of alternating current electrical circuits. According to Steinmetz, a classical or static phasor is a complex number that represents a sinusoidal function whose amplitude, phase and angular frequency are constants and it transforms ordinary differential equations with constant coefficients, which are models for alternating current electrical circuits, in linear systems with complex coefficients. When either amplitude, phase or angular frequency is no longer constant, the phasor theory must be adapted in such a way to preserve the classical results. In this new theory, which deals with a large class of functions rather than only sinusoidal functions, the phasor is called dynamic or time-variable
    phasor. Following this line, the main objective of this work is to present three new
    theories about dynamic phasors built from integral transforms, namely, the short-term Fourier transform, the generalized Laplace transform and the Hilbert transform. More precisely, the dynamic phasors arise through injective linear operators between suitable vector spaces and they have similar properties to those of the dynamic phasors usually found in the literature.

15
  • RODRIGO DE PAULA RODRIGUES
  • Curvature Scale Space-based Signatures Applied to Non-Invasive Load Monitoring of Residential Electrical Loads

  • Leader : PAULO MARCIO DA SILVEIRA
  • MEMBRES DE LA BANQUE :
  • CARLOS AUGUSTO DUQUE
  • JOAO ONOFRE PEREIRA PINTO
  • JOSE MARIA DE CARVALHO FILHO
  • LUIZ EDUARDO BORGES DA SILVA
  • PAULO MARCIO DA SILVEIRA
  • Data: 18 déc. 2020


  • Afficher le Résumé
  • Non-intrusive load monitoring (NILM) systems have gained extensive interest due to their potential role regarding power savings for residential customers. These systems, which are mostly based on stages of detection and classification of transients on aggregated signals, rely heavily on load signatures. In the literature, the image-based representations of voltage-current (V-I) trajectories are claimed as the most effective individual steady-state signatures for appliance classification. However, these representations inherit some drawbacks from their generation process and they are thus incapable of inheriting all the information encompassed by V-I trajectories. This work then proposes two steady-state appliance signatures derived from the curvature scale space of V-I trajectories. These signatures aim to improve the image representations of V-I trajectories by encompassing structural elements related to the general shape of such trajectories as well as some characteristics neglected during their generation. A group of load signatures formed from the proposed signatures was evaluated on direct load classification and load disaggregation scenarios for four publicly available datasets. The results achieved by the proposed representations surpassed the sole employment of a reference image-based V-I signature for all the test scenarios executed. Also, some of the evaluated signatures outperformed all known proposals that are exclusively based on steady-state signatures for load classification on a given benchmark dataset as well as on two other public datasets

2019
Thèses
1
  • MATEUS DIAS BRAGA
  • Capacidade de Hospedagem de Sistemas de Distribuição com Inserção de Geração Distribuída Utilizando o OpenDSS

  • Leader : PAULO FERNANDO RIBEIRO
  • MEMBRES DE LA BANQUE :
  • BENEDITO ISAIAS LIMA FULY
  • ELIANE VALENCA NASCIMENTO DE LORENCI
  • JOSE LUIZ REZENDE PEREIRA
  • PAULO FERNANDO RIBEIRO
  • Data: 25 avr. 2019


  • Afficher le Résumé
  • The use of distributed generation - mainly of photovoltaic solar panels - have been
    increasing in the last years. Promoting the development of renewable energy has become a
    common goal of the World and Brazil as well. The seek for alternative energy sources allied
    with the generation of clean energy has increased considerably the use of photovoltaic solar
    energy. In addition, agreements such as the Kyoto Protocol and Paris have also influenced it.
    Another factor that is interesting to mention is the price reduction in this type of energy, since
    in previous decades it was unfeasible, presenting very high prices. Moreover, the growth of
    this type of energy is quite beneficial to the society because it diversifies the energy matrix,
    decreasing the dependence on large hydroelectric and/or thermal plants. On the other hand, it
    also generates technical, economic and social uncertainties and concerns. Within this context,
    this work seeks to present the impacts of the distributed generation on the electric power
    systems. From the technical point of view, the main problems reported in the literature due to
    high insertion of distributed photovoltaic systems are: overvoltage, harmonic distortions,
    voltage imbalances, thermal capacity of lines and transformers, among others. In this way,
    this paper work aims to analyze the hosting capacity of a distribution system against
    overvoltage and harmonics. OpenDSS software is used with MATLab in order to evaluate the
    system against high insertion of distributed generation. Some factors that directly influence
    the hosting capacity values of this test system (13 buses) against overvoltages and harmonic
    distortions are presented, compared and discussed.

2
  • IBERÊ CARNEIRO DE OLIVEIRA
  • Análise Econômica da Inserção de Painéis Fotovoltaicos no Campus da UNIFEI - Itajubá com Simulação de Monte Carlo

  • Leader : BENEDITO DONIZETI BONATTO
  • MEMBRES DE LA BANQUE :
  • BENEDITO DONIZETI BONATTO
  • FERNANDO NUNES BELCHIOR
  • JOSE LUIZ REZENDE PEREIRA
  • MOISES DINIZ VASSALLO
  • VICTOR EDUARDO DE MELLO VALERIO
  • Data: 10 juin 2019


  • Afficher le Résumé
  • This dissertation presents a methodology to estimate the economic return and its associated risk of investment in photovoltaic generation (PV) systems through Monte Carlo simulation. In order to do so, it was used real electricity generation and consumption data from UNIFEI, Itajubá campus, with the use of a supervisory system, and designed a PV generation system able to supply the consumed electrical energy by UNIFEI from the power utility. Based on this design, two architectures were modeled for the implantation of this PV system: a centralized system built to the ground, and a decentralized system spread over the roofs of the UNIFEI buildings in Itajubá. It was established the main stochastic variables that influence the economic return of the PV system, such as cost of capital, electric power generation, CAPEX, OPEX, residual value, energy tariff variation and system reliability. With these data the Monte Carlo simulation was performed for both systems and calculated the values Net Present Value (NPV), Internal Rate of Return (IRR) and Profitability Index (RI) of the systems as well as their standard deviations.

3
  • KELI CRISTINE SILVA ANTUNES
  • Análise do Desempenho das Proteções Diferenciais de Fase e Baseada em Sequência Negativa para Transformadores de Potência

  • Leader : PAULO MARCIO DA SILVEIRA
  • MEMBRES DE LA BANQUE :
  • AURELIO LUIZ MAGALHAES COELHO
  • FREDERICO OLIVEIRA PASSOS
  • LUIS HENRIQUE LOPES LIMA
  • PAULO MARCIO DA SILVEIRA
  • Data: 1 juil. 2019


  • Afficher le Résumé
  • This work addresses a comparison between negative sequence differential protection and
    phase differential protection. Firstly, this work presents an overview about the main topics
    regarding transformer protection which are: turn-to-turn faults, symmetrical components,
    phase differential protection and negative-sequence differential protection. Those topics
    are necessary for the development and understanding of this work.
    In order to analyze the performance of the negative-sequence differential protection, some
    hardware-in-the-loop tests were performed using the Real Time Digital Simulator (RTDS)
    and a transformer protection relay. The same tests were performed using a virtual differential
    protection relay modeled on the RTDS also. Two electrical systems were modeled for
    the application of fault conditions. The first system has a transformer with a 1:1 voltage
    ratio and no phase shift between the primary and secondary signals. The second system,
    on its turn, has a step-down transformer with phase lag.
    Moreover, this work presents the results for the phase protection and negative-sequence
    protection tests of both commercial relay and virtual relay. The applied faults consist of
    turn-to-turn faults and unbalanced external faults. In addition, different loading levels
    were applied to the transformers in order to verify their influence on the sensitivity of
    the differential protections. Finally, the performance of the negative-sequence differential
    protection under the different conditions is analyzed and the conclusions are presented.

4
  • JOÃO FILIPE RENÓ PEIXOTO DE AZEVEDO SILVA
  • Controlador TFL/LTR Aplicado ao Controle de Sistemas em Rede Suscetveis a Perdas de Comunicacao

  • Leader : JEREMIAS BARBOSA MACHADO
  • MEMBRES DE LA BANQUE :
  • FERNANDO HENRIQUE DUARTE GUARACY
  • JEREMIAS BARBOSA MACHADO
  • LUIS HENRIQUE DE CARVALHO FERREIRA
  • REJANE BARBOSA SANTOS
  • Data: 3 juil. 2019


  • Afficher le Résumé
  • This dissertation presents a fault-tolerant controller applied to a system containing communication
    channels susceptible to data loss. The system is represented by a quadruple-tank
    plant in which the data transmission between the controller and the plant is done through
    network links. The Target Feedback Loop/Loop Transfer Recovery controller class, capable
    of dealing passively with the intermittent loss of the actuator or sensor signal, is employed.
    In this scenario, the controller structure and the calculations necessary for its construction
    are described, as well as the mathematical modeling strategies of the data transport faults.
    By employing the designed compensator, the results obtained in the simulations show that
    the system response remains stable and with proper reference tracking, even in the event of
    an actuator or sensor data loss.

5
  • JANSEN PAULA VILLIBOR
  • Avaliação Técnico-Econômica da Utilização do Cobre na Reforma dos Enrolamentos de Transformadores de
    Distribuição Originalmente Dimensionados para Alumínio

  • Leader : ESTACIO TAVARES WANDERLEY NETO
  • MEMBRES DE LA BANQUE :
  • ALESSANDRA FREITAS PICANÇO
  • CREDSON DE SALLES
  • EDUARDO CRESTANA GUARDIA
  • ESTACIO TAVARES WANDERLEY NETO
  • Data: 9 juil. 2019


  • Afficher le Résumé
  • This study aims to analyze, technically and economically, the benefits of the copper
    utilization on new windings of repaired distribution transformers, originally designed for
    aluminum. Three commercial single-phase distribution removed from the distribution network,
    after failing, were repaired with different materials (copper and aluminum), ranked at the
    standard energy efficiency levels (E and C) and then submitted to routine tests and temperature
    rise test. All the tests were performed at LAT-EFEI - High Voltage Laboratory in accordance
    to Brazilian standards and the Brazilian Labeling Program (PBE) for oil-immersed distribution
    transformers. The technical evaluation compares the losses of the transformers removed from
    the network, after being manufactured, with the measured losses after the repair process and
    the temperature rise test results between the repaired transformers. Also, was made a
    comparative analysis between the copper and aluminum, highlighting their main properties,
    with short utilization historical in distribution transformers and the implication of which metal
    utilization in distribution transformers. The economic analysis is based on load losses and noload
    losses capitalization along the analysis period and compares the investment in more
    efficient transformers, repaired with copper in energy efficiency level C, versus standard
    transformers made with aluminum (repaired and new) in energy efficiency level E, providing
    the net present value and the investment payback time, in different situations.

6
  • GIORDANA MARIA RODRIGUES
  • Antena de microfita para emprego em sistemas de micro-ondas
    operando em 5GHz

  • Leader : DANILO HENRIQUE SPADOTI
  • MEMBRES DE LA BANQUE :
  • DANILO HENRIQUE SPADOTI
  • JOSE ANTONIO JUSTINO RIBEIRO
  • RENAN ALVES DOS SANTOS
  • TALES CLEBER PIMENTA
  • Data: 10 juil. 2019


  • Afficher le Résumé
  • This work presents the design procedure and the analysis of the radiator elements, for the
    operational frequency of 5 GHz, using microstrip antennas to be applied in the helicopters.
    The designed microstrip antenna is a compact structure, with small thickness and reduced
    dimensions, being particularly attractive to be assembled in the aircraft vertical tail in special,
    its use will not have influence in the aerodynamics aspects, which represents a serviceable
    characteristic when compared to others models of antennas. The microstrip antenna has a
    several applications in addition to the usual for communications systems, for example in
    equipment to avoid collision between aircraft. In addition to the theoretical development for
    the chosen model, simulation programs such as HFSS® from ANSYS® and Matlab® will
    be used for other design calculations. A prototype was developed in order to perform the
    characterization of the studied antenna, from the analysis of its behavior operating in the
    resonance frequency, to determine the far field and consequent evaluation of the parameters
    of gain and return loss. The designed antenna with dimensions 2,4 x 1,84 x 0,158 cm
    presented gain of 7,06dBi and return loss of -32,12 dB, working in 5,46GHz, which makes it
    extremely useful for use in rotary wing aircraft.

7
  • LUIZ ARTHUR SILVA MOURA
  • Análise Comparativa de Técnicas para Controle de um Manipulador Robótico Utilizando o Sensor Kinect

  • Leader : GUILHERME SOUSA BASTOS
  • MEMBRES DE LA BANQUE :
  • GUILHERME SOUSA BASTOS
  • LEONARDO OLIVI
  • LUIZ EDIVAL DE SOUZA
  • Data: 12 juil. 2019


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  • This paper aims to control a robot arm using Microsoft Kinect with different methods
    applied, such as forward and inverse kinematics, fuzzy logic control, and dynamics model
    with a proportional-derivative controller. Moreover, this paper proposes to perform a
    comparative analysis of these methods. The Kinect sensor will be used to collect position
    and rotation data of the human arm. ROS sends the information received from the human
    arms to V-rep simulator, which robot models are created based on the ED-7220C robot
    arm. The results validate the methods applied and suggests high performance on methods
    that uses hand position data.

8
  • Francinei Lucas Vieira
  • Impacts of Linear and Nonlinear Load Modelling on Power Harmonic Metrics inSmart Grid Context Using OpenDSS

  • Leader : PAULO FERNANDO RIBEIRO
  • MEMBRES DE LA BANQUE :
  • ANTONIO CARLOS ZAMBRONI DE SOUZA
  • BENEDITO DONIZETI BONATTO
  • FERNANDO NUNES BELCHIOR
  • PAULO FERNANDO RIBEIRO
  • Data: 26 août 2019


  • Afficher le Résumé
  • Os sistemas de potência estão passando por grandes mudanças à medida que a geração distribuída, os dispositivos eletrônicos de potência e as aplicações que tornam as redes elétricas mais inteligentes são inseridos nos sistemas. Embora as mudanças sejam benéficas para satisfazer as necessidades de cargas locais, problemas podem surgir nos parâmetros de desempenho elétrico devido ao impacto das alterações na rede. E para realizar estudos e verificar o impacto de novos elementos nos sistemas de distribuição, as ferramentas de simulação são recursos importantes para o planejamento de pesquisadores e engenheiros. Esta dissertação é um estudo de modelagem harmônica que abrange, por exemplo, os efeitos de cargas lineares agregadas em estudos harmônicos, a modelagem e composição de dispositivos lineares e não-lineares e o uso de sistemas equivalentes de potência para simulação. As simulações são realizadas usando diferentes modelos de carga para verificar o impacto e a sensibilidade da impedância do sistema e das tensões harmônicas resultantes. Fontes harmônicas representando cargas não-lineares típicas são conectadas ao sistema para analisar a distorção de tensão e a impedância do sistema em diferentes barramentos das redes simuladas. Os sistemas foram modelados e simulados no software OpenDSS. Os resultados mostraram que tanto o modelo quanto a composição de cargas possuem um impacto significativo na impedância do sistema e no amortecimento de ressonâncias paralelas. Porém, uma avaliação abrangente de cargas e geradores distribuídos através de medições é necessária para melhor entender seus comportamentos nas métricas de desempenho elétrico.

9
  • RICARDO OLIVEIRA GOMES
  • STUDY CASE OF IMPACTS IN POWER QUALITY AND ANALYSIS OF TIME VARYING HARMONICS
    PRODUCED BY PHOTOVOLTAIC INVERTERS UNDER TRANSIENT CONDITIONS

  • Leader : PAULO FERNANDO RIBEIRO
  • MEMBRES DE LA BANQUE :
  • ANTONIO CARLOS ZAMBRONI DE SOUZA
  • CARLOS AUGUSTO DUQUE
  • FERNANDO NUNES BELCHIOR
  • PAULO FERNANDO RIBEIRO
  • Data: 27 août 2019


  • Afficher le Résumé
  • As renewable energy use increases mainly by photovoltaic generation, a large number of
    inverters are connected to the grid creating harmonic distortion. Each inverter topology
    and control methodology has advantages and disadvantages. A comparative study was
    carried out between the three main internal inverters topologies, analyzing their content
    and harmonic distortion (THD). A second study was carried out on two models of Fronius
    inverters, located at an university building with photovoltaic plant of 27kWp. Measurements
    were taken at the building substation and directly at inverters outputs analyzing standard
    operation, startup, shutdown and energy variation due to solar irradiation. To perform
    these analyzes, time-frequency analysis techniques such as STFT, Wavelet and Wavelet
    Packet were used. The techniques are effective to analyze and identify the harmonic system
    components, as well as increase in magnitude over time. In addition, the techniques were
    also effective on identifying the behavior of other loads and their harmonics propagation
    in the grid.

10
  • ALESSANDRO GUIMARÃES FIORESE
  • Microrrede com veículos elétricos: impacto na vida útil das baterias conectadas à rede

  • Leader : ANTONIO CARLOS ZAMBRONI DE SOUZA
  • MEMBRES DE LA BANQUE :
  • ANTONIO CARLOS ZAMBRONI DE SOUZA
  • JOAO GUILHERME DE CARVALHO COSTA
  • JULIO CESAR STACCHINI DE SOUZA
  • MAURICIO CAMPOS PASSARO
  • Data: 26 sept. 2019


  • Afficher le Résumé
  • For the past 40 years, the world has been changing its environmental awareness. In the last
    decade, this has been manifested by the search for alternative energy sources that are less
    environmentally aggressive, adopting those that are less carbon dependent. Examples are
    electric cars replacing fossil-fueled cars and using the sun and wind to generate electricity
    rather than thermal power plants.
    Wind and solar generation have the possibility to be implemented on a small scale and
    distributed power generation enables the demarcation of micro grids that have the capacity
    to generate much of the energy needed.
    The continuous developments toward active distribution systems have been providing the
    necessary conditions for islanded microgrids operation. In this mode, the islanded regions
    are expected to sustain the system operation within adequate limits, locally performing
    several control actions previously assumed by the main grid.
    Among these controls, the guarantee of generation/demand balance is one of the most
    critical aspects, which due to the limited amount of generation capacity can lead to
    massive load shedding. In this perspective, this paper seeks to evaluate the effects of plugin
    electric vehicles (PEVs) to improve energy balance management of islanded microgrids.
    For this, a holistic methodology is proposed to determine whether the implementation of
    sophisticated controls for the use of PEVs as flexible resources render actual benefit for
    the islanded network.
    The adjustment’s coefficients of the semi-empiric methodology proposed by Sarasketa-
    Zabala were found allowing the evaluation of the degradation generated in PEVs batteries
    in supply energy to the grid (V2G).
    Simulations are held in the IEEE 34-bus test system considering modifications to represent
    a microgrid environment.
    The results indicate that the use of PEVs as a flexible resource can significantly facilitate
    the generation / demand balance management by substantially reducing load shedding
    when the micro grid operates.
    However, improved energy balance management comes at the expense of a high degree of
    deterioration of the PEV’s battery charge capacity.

11
  • GABRIEL PAIVA TOMAZ RIBEIRO
  • Probabilistic Methodology for Evaluating Costs of Failures in Transmission Line Towers

  • Leader : PEDRO PAULO BALESTRASSI
  • MEMBRES DE LA BANQUE :
  • AGNELO MAROTTA CASSULA
  • ANTONIO CARLOS ZAMBRONI DE SOUZA
  • JOAO GUILHERME DE CARVALHO COSTA
  • PEDRO PAULO BALESTRASSI
  • Data: 29 oct. 2019


  • Afficher le Résumé
  • This paper presents a new probabilistic methodology for evaluating costs of transmission line failures, considering the event “falling of a tower”. In Brazil, the electrical energy regulatory agency, ANEEL, establishes acceptable values to the system failure frequency and duration, and defines penalties to be applied to the transmission companies when these limits are exceeded. The proposed methodology, based on chronological Monte Carlo simulation, is used to sample several operating months for a transmission line, which allows to determining reliability indices, expected values and probability distributions of the system cost parameters. A computational program using Matlab platform is applied to a 230kV transmission line of Paraná state, Brazil, in order to perform several numerical examples and sensitivity anal-ysis. All the developments are commented, and the obtained results are properly discussed.

12
  • LUIZ AMERICO RICO DE SOUSA
  • PROPOSAL FOR MEASUREMENT OF HARMONIC AND INTER-HARMONIC DISTORTIONS WITH AMPLITUDE VARIABLE IN NONLINEAR LOADS

  • Leader : PAULO MARCIO DA SILVEIRA
  • MEMBRES DE LA BANQUE :
  • CARLOS AUGUSTO DUQUE
  • FERNANDO NUNES BELCHIOR
  • JOSE MARIA DE CARVALHO FILHO
  • LEANDRO RODRIGUES MANSO SILVA
  • PAULO MARCIO DA SILVEIRA
  • Data: 29 oct. 2019


  • Afficher le Résumé
  • Currently the harmonic distortions analysis in power systems is performed in the frequency domain and considering the signals in steady state. Most of quality indices were developed considering the periodic voltage and current signals and as function of the Fourier Transform application. However, with the growth of distributed generation and the installation of nonlinear loads, electrical systems are becoming increasingly complex and voltage and current signals no longer have the characteristics of periodicity, distributed generation and nonlinear loads introduce harmonics, subharmonics and interharmonics into the power system, other power quality problems as voltage swells and sags, voltage fluctuations are also found in power systems. The IEC 61000-4-7 and IEC 61000-4-30 standards present methods such as the 12-cycle time window Fourier Transform for calculating harmonics and interharmonics, but these methods may not be efficient in signal analysis with amplitude variations and distortions, they may have frequency spectrum suffers and errors in the global indicators. In this context, new analysis methodologies should be considered for a more adequate analysis of the electrical power system signals. These techniques should have characteristics such as providing frequency information and time domain amplitude behavior. Among the techniques approached in this work, we highlight the window time samples acquisition, Fourier transform with overlap samples and parametric ESPRIT method. Methodologies for calculating global indicators for interharmonics and subharmonics are discussed. This dissertation presents the performance analysis and application of the proposed methods in synthetic signals and field measured signals.

13
  • ISAC ANTONIO DOS SANTOS AREIAS
  • Development of a specific current sensor for machine current signature analysis

  • Leader : LUIZ EDUARDO BORGES DA SILVA
  • MEMBRES DE LA BANQUE :
  • ERIK LEANDRO BONALDI
  • GISCARD FRANCIMEIRE CINTRA VELOSO
  • LUIZ EDUARDO BORGES DA SILVA
  • RONDINELI RODRIGUES PEREIRA
  • WILSON CÉSAR SANT`ANA
  • Data: 31 oct. 2019


  • Afficher le Résumé
  • This paper presents the development of a new specific current sensor for machine current signature analysis. The fundamental current component attenuation is performed in order to create a more sensitive and effective method for the other spectral components acquisition. The sensor consists of a modified current transformer whose differential, which is the inclusion of an auxiliary winding, produces a magnetic field that provides attenuation of the fundamental component in the sensor output signal. The proposed methodology assumes that the fundamental component attenuation results in the increase of the space occupied by the spectral components, without the fundamental, in the dynamic range of operation of the sensor and the acquisition system. In addition, the frequency and phase information of the fundamental component are kept in the signal. The methodology was tested using an 0,5 cv motor, with current signal acquired simultaneously by the proposed sensor and a current transformer. The signals spectra obtained at a resolution of 24 bits were compared, later they were decimated to 8 bits and compared again. The results show that the signal obtained by the proposed sensor did not remove the near fundamental components, such as the sideband components, and the respective decimated signal to 8 bits presented the largest error of 23.6% in relation to the original signal in the 104.7 Hz component, while the largest signal error obtained by CT was 31.8% at 1276 Hz. These results represent a good advance towards obtaining a current acquisition system applied to MCSA without requiring high resolution.

14
  • HUGO SOUZA RIOS
  • ANALYSIS OF ATTRACTIVITY VARIATION IN PHOTOVOLTAIC GENERATION UNDERTAKINGS REGARDING REGULATORY CHANGES

  • Leader : JOSE WANDERLEY MARANGON LIMA
  • MEMBRES DE LA BANQUE :
  • ALEXANDRE RASI AOKI
  • EDUARDO CRESTANA GUARDIA
  • JOSE WANDERLEY MARANGON LIMA
  • Data: 1 nov. 2019


  • Afficher le Résumé
  • In recent years, small generation has been gaining ground in distribution networks due to the reduction in the costs of its implementation and operation, as well as the application of incentives such as feed-in tariff, net-metering and differentiated financing rates. In Brazil, in particular, Photovoltaic Distributed Generation (PVDG) has gained significant space in view of the regulation of net-metering (Normative Resolution 482 of 2012), the value of energy tariffs, and the encouragement of renewable sources under various financing and tax instruments. The resolution that coordinates GD in Brazil has undergone several modifications in order to adapt to the reality of the electricity sector. However, the model currently in use has been challenged mainly by distributors who feel threatened by the non-payment of their transportation and “storage” service. Regulatory changes are being discussed which, if approved, could have a high impact on the growth of micro and distributed mini-generation: modification of the pricing method - discussion formally initiated from Public Consultation 02 of 2018 - and modification in the form of energy compensation generated from these ventures - argument officially initiated from Public Consultation 10 of 2018. This work aimed to measure the financial impacts that these changes in regulation may cause, resulting in the variation of the attractiveness of these projects. In order to have an overview of the impacts, five cities were selected, one from each region of Brazil, taking into account their own characteristics, such as: average daily solar radiation, energy cost history of the local energy distributor and taxes on the electric bill. Then, the PVDGs of different modalities - rooftop, shared generation PV and remote consumption PV - were projected, following standard models, in order to maintain a criterion that allows the comparison between the different locations. A financial analysis was performed using the Net Present Value (NPV) method, allowing a quantitative analysis of the results presented. The results show a strong sensitivity to the proposed modifications - even the mildest alternative of each modification - tending to greatly increase the payback of PVDG investments. Due to the differentiated tax incentive, the ventures located in the state of Minas Gerais presented the shortest return times in all scenarios. However, investments in other states had their payback times severely increased, and were considered unfeasible in some cases.

15
  • CARLOS JOSÉ DOS SANTOS
  • Selection of voice codecs by balancing QoS and QoE aided by Hierarchical Process Analysis (AHP) algorithm

  • Leader : LUIZ EDIVAL DE SOUZA
  • MEMBRES DE LA BANQUE :
  • JOSE ANTONIO JUSTINO RIBEIRO
  • LUIZ EDIVAL DE SOUZA
  • THIAGO CAPRONI TAVARES
  • Data: 13 nov. 2019


  • Afficher le Résumé
  • In decision-making processes, many variables need to be considered. These variables can be discovered by investigating the facts or supported by numerical analysis data. In general, the findings of the relevant facts are provided because of the previous experiences of the decision-maker and have non-numerical structures, i.e., are expressed by linguistic values. Thus, the decision-makers have in their daily work, difficulties in grouping these linguistic values into those of numerical origin. Typically, in the computational network tract, countless data is generated every second. Although there are specialists trained to analyze these data, the process can be exhausting due to the very high volume. The use of tools that assist in the analysis and decision of actions to be taken more and more is necessary. Thus, heuristic analyses should be added to a thorough analysis of mathematical models of the systems used for decision support. The main objective of this work is to propose a new algorithm for the selection of Voice encoders (codecs) based on the methodology of Multicriteria – AHP (hierarchical process analysis) called AHP Codec Selection. AHP Codec Selection is then a tool used to optimize QoS in convergent networks. The main benefit achieved with the AHP Codec Selection algorithm was to select the different codecs, data network states. However, the study also demonstrates the influence of these codecs on the inside of converged data networks. Given the growth of this type of network, methods of adjustments and improvement of the quality of services offered become indispensable. An example of application of the proposed algorithm was used to manage the network of the Federal Institute of Education, Science and Technology of the south of Minas Gerais-Campus Avançado Três Corações.

16
  • CARLOS EDUARDO DE OLIVEIRA MONTEIRO
  • WATER FLOW FORECAST FOR SMALL HYDROELECTRIC POWER PLANTS

  • Leader : PEDRO PAULO BALESTRASSI
  • MEMBRES DE LA BANQUE :
  • ANTONIO CARLOS ZAMBRONI DE SOUZA
  • MADSON CORTES DE ALMEIDA
  • PEDRO PAULO BALESTRASSI
  • Data: 2 déc. 2019


  • Afficher le Résumé
  • This dissertation has the main aim to identify stochastic models ARIMA (Autoregressive Integrated Moving Average Model) that provide monthly water inflow forecast in a mid-term (annual) and in a short-term (month) horizon for a small hydroelectric power plant that can be reactivated. The case study is composed of a micro hydrographic basin that hosted a small hydroelectric power plant that has been deactivated more than 40 years. Hydrologic data for this basin has been obtained following its hydrologic study, as well as its motorization study. The identification of the water inflow forecast tentative models was made with previous analysis of historic data, its transformation and subsequent Box-Jenkins methodology application. The short-term and mid-term model selection was made with the tentative model’s choice that presented the lowest MAPE (Mean Absolute Percent Forecast Error) indicator for each analyzed horizon. With the selected models it was possible to make short-term forecasts of 20,02% of MAPE and mid-term forecasts of 28,25% of MAPE. A comparison was made between the forecasts obtained through chosen models and the ONS’s (Independent System Operator) forecasts in Paraná river basin’s potentials. The short-term model didn’t show neither superior, neither inferior performance related to ONS’s models, and mid-term model showed inferior performance. Finally, the forecasted ENA (Affluent Natural Energy) and the ENA that would be observed were compared at the potential in 2008. On this situation, the forecasted energy was 0,266% higher than the observed energy, which means an excellent result.

17
  • HANNELI CAROLINA ANDREAZZI TAVANTE
  • Functional programming applied to electrical engineering

  • Leader : BENEDITO DONIZETI BONATTO
  • MEMBRES DE LA BANQUE :
  • BENEDITO DONIZETI BONATTO
  • EDMILSON MARMO MOREIRA
  • FERNANDO NUNES BELCHIOR
  • MAURILIO PEREIRA COUTINHO
  • Data: 3 déc. 2019


  • Afficher le Résumé
  • Many engineering projects rely on software to execute simulations and analysis of a wide variety of domains. Computer programs are great allies of the engineers when it comes to simulations, including the ones for electromagnetic transient analysis. However, a single programming paradigm (the imperative paradigm) seems to have dominated most of the commercial and academic applications. This work presents and implements an algorithm to analyse simple electromagnetic transient circuits adopting functional programming. The code uses the nodal analysis found on industry programs like the EMTP (Electromagnetic Transients Program). The results of adopting the Haskell language and functional programming are very favourable to the engineering community: programs with higher chances to have fewer bugs, with concise implementations and with more focus on the mathematical aspects of the algorithm.

18
  • BRUNO RENÓ GAMA
  • FPGA system for early detection of insulation damage in electrical machines based on impedance spectrum analysis

  • Leader : LUIZ EDUARDO BORGES DA SILVA
  • MEMBRES DE LA BANQUE :
  • ISMAEL NORONHA
  • LUIZ EDUARDO BORGES DA SILVA
  • RONDINELI RODRIGUES PEREIRA
  • WILSON CÉSAR SANT`ANA
  • Data: 6 déc. 2019


  • Afficher le Résumé
  • This work presents a system developed for early fault detection on insulation of electrical machines. The system is composed by hardware and software, and uses the impedance spectrum analysis for early damage detection. The developed system is responsible for injection of wide range of frequencies into the machine under test. For each injected signal, the machine impedance is measured. At the end of the process, the impedance spectrum is obtained. The obtained spectra are compared with a reference spectrum, called baseline. Differences between the baseline and the spectrum under analysis indicate damages into machine insulation. Since a visual comparison between spectra allows to subjective interpretations, a statistical indicator is used for the correct spectrum analysis, and better precision at fault diagnosis. It was used the STEMLab platform for the system development. It is a new board in the market and presents the necessary peripherals for the building of a complete instrumentation low cost system. The board has a SoC Zynq-7000 device, which integrates an FPGA and an ARM processor. It also has two ADCs and two DACs of high speed. The hardware is responsible for the signal generation and acquisition system, and also for a TCP/IP server execution. The server responds to remote clients solicitations and executes generation and acquisition operations. It also executes the transmission, via network, of the acquired data. The software, build in c# language, besides supplying the operations configurations for the hardware, allows the visualization of the acquired spectra and calculates the statistical indices proposed for the results analysis.

19
  • PEDRO ANDRADE DE OLIVEIRA
  • Model Predictive Control Applied on Cascaded H-Bridge Converter with Link DC voltage Stabilization

  • Leader : LUIZ EDUARDO BORGES DA SILVA
  • MEMBRES DE LA BANQUE :
  • LUIZ EDUARDO BORGES DA SILVA
  • ROBSON BAUWELZ GONZATTI
  • RONDINELI RODRIGUES PEREIRA
  • SÍLVIA COSTA FERREIRA
  • Data: 13 déc. 2019


  • Afficher le Résumé
  • This work proposes ways to over challenge two main problems faced in the using of sinite sontrol set model based predictive control (FCS-MPC) applied to a cascaded H-bridge multilevel converter (CHB). Despite very efcient in the control of power converters, FCS-MPC may require, depending on the application, an enormous computational burden, which makes it unfeasible with traditional FCS-MPC technics. Furthermore, when applied to multilevel converters, an unbalance in the DC link’s voltage is generated causing instability in the system. Starting from the mathematical model of the coupling flter, which links the converter to the grid, it is possible to discretize the system model and include nonlinearities that allow voltage balancing in the DC links capacitors. It is also proposed a systematic method to reduce the number of converter’s states resulting in a reduction of the computational burden of the control system. The practical results and simulations obtained show the feasibility of the proposed FCS-MPC technique, both in the reduction of switching states as well as in the control of DC links voltage, while the FCS-MPC algorithm applied to a STATCOM (built with a CHB converter of seven levels) compensates the reactive power.

Thèses
1
  • PEDRO EUGÊNIO MARCONDES JUSTINO RIBEIRO
  • Compensação de Harmônicas Utilizando Máquina Síncrona

  • Leader : LUIZ EDUARDO BORGES DA SILVA
  • MEMBRES DE LA BANQUE :
  • JOAO ONOFRE PEREIRA PINTO
  • LUIGI GALOTTO
  • LUIZ EDUARDO BORGES DA SILVA
  • RAYMUNDO CORDERO GARCIA
  • ROBSON BAUWELZ GONZATTI
  • RONDINELI RODRIGUES PEREIRA
  • Data: 29 mars 2019


  • Afficher le Résumé
  • The development of electronics and semiconductors brought the circulating of harmonic currents in the electric power grids. These currents can cause losses in conductors and unwanted resonances and have become one of the biggest problems in electric power systems. Therefore, many solutions are presented in the literature, such as, i) specials design transformers windings; ii) reactors; iii) passive resonant filters; iv) parallel active filter; v) hybrid filters. However, none of these solutions has good applicability in high-voltage high-power systems. This dissertation proposes an alternative method off using synchronous machine to compensate the harmonic content of a non-linear load, by controlling its field current. For this equipment, it is being proposed the name of Supersynchronous Active Filter (FAZ). This equipment can be implemented by retrofitting of installed synchronous machines, or in new projects.
    The viability of the synchronous operation for the reactive power compensation is described; it was presents the field and flux machine modeling. The simulation off the operation is shown, for a compensation of a non-linear load, and a comparison with a reference model (parallel active filter) was done. Finally, discussions are made considering the results and the implementation difficulties.

2
  • THIAGO POUZA MUSSOLINI
  • Uma Metodologia para Projeto de uma Referência de Corrente CMOS Independente da Temperatura
    Otimizada para Aplicações de Sinais Mistos

  • Leader : ROBSON LUIZ MORENO
  • MEMBRES DE LA BANQUE :
  • DALTON MARTINI COLOMBO
  • LEONARDO BRESEGHELLO ZOCCAL
  • LEONARDO MESQUITA
  • LUIS HENRIQUE DE CARVALHO FERREIRA
  • PAULO CESAR CREPALDI
  • ROBSON LUIZ MORENO
  • Data: 6 juin 2019


  • Afficher le Résumé
  • This work presents a design methodology for a CMOS temperature-independent current
    reference. This current reference has the following characteristics: high accuracy, good
    PSRR and low variation; being optimized for mixed signal applications. The topology is
    based on bootstrap current references that present a PSRR up to 60 dB, which is required
    for the proposed applications since they employ circuits where high-frequency switching
    noise is present. The proposed approach was successfully verified in a standard CMOS
    0.35 μm process. The electrical simulations and laboratory measurements confirm that
    for a power supply between 2.7 V and 3.6 V and temperatures between -40 oC to 80 oC
    range. Finally, the proposed current reference exhibits an accuracy of ±0.5% and a mean
    relative temperature dependency of 62.5 ppm/oC.

3
  • ARNALDO DEL RISCO SÁNCHEZ
  • Estratégias para o controle de modo comum do Par Diferencial Simétrico CMOS de Ultra-Baixa Tensão e
    Ultra-Baixa Potência

  • Leader : LUIS HENRIQUE DE CARVALHO FERREIRA
  • MEMBRES DE LA BANQUE :
  • DALTON MARTINI COLOMBO
  • LUIS HENRIQUE DE CARVALHO FERREIRA
  • ODILON DE OLIVEIRA DUTRA
  • PALOMA MARIA SILVA ROCHA RIZOL
  • PAULO CESAR CREPALDI
  • ROBSON LUIZ MORENO
  • Data: 11 juin 2019


  • Afficher le Résumé
  • This work presents four topologies for Common Mode Rejection Ratio (CMRR) compensation
    in a ultra-low-voltage and ultra-low-power symmetrical differential pair with
    transistors operating in the weak inversion region. The theoretical analysis of the compensation
    strategies proposed as well as the topologies to be used to improve the common mode
    response is shown. The proposed strategies were verified using a Monte Carlo simulation.
    Using one of the strategies, a symmetric differential pair architecture without a tail current
    is proposed, which reduces the supply voltage of the circuit by performing the common
    mode control in parallel.
    One of the proposed topologies is implemented in an IBM-130 nm BiCMOS process. The
    proposed circuit has a CMRR of 70,22 dB, transconductance of 5.33 nS, bias current
    of 4 nA, supply voltage of 400 mV and power consumption of 10 nW, confirming its
    compatibility with ultra-low power circuits .

4
  • DECIO RENNO DE MENDONCA FARIA
  • SISTEMA ELETRÔNICO DE RASTREAMENTO E DIRECIONAMENTO DE SINAIS PARA REDE S 5G E IoT

  • Leader : DANILO HENRIQUE SPADOTI
  • MEMBRES DE LA BANQUE :
  • DANILO HENRIQUE SPADOTI
  • FERNANDA RODRIGUES DA SILVA
  • KENEDY MARCONI GERALDO DOS SANTOS
  • MATEUS AUGUSTO FAUSTINO CHAIB JUNQUEIRA
  • RENAN ALVES DOS SANTOS
  • Data: 24 juin 2019


  • Afficher le Résumé
  • Currently, the mobile communication system is headed for a new technological leap
    called fifth generation (5G). In this system each user w ill have their own broadband network
    and new technologies will facilitate the machine to machine connection (M2M) supporting
    the Internet of Things (IoT) concept where electronic devices can exchange messages with
    each other or with the man. To reach this goal, the new network must necessarily be
    ultradense with numerous stations serving areas that previously were served by a single
    station. The complexity of systems, especially the control system, will be much greater than
    the current one. In the specific case of a cell change it is of great value to estimate to which
    cell the mobile unit moves, but this information is not currently available to the Control Unit
    called the Mobility Management Entity (MME).
    This work proposes the use of a digital localization system that converts the angle of arrival of the signal (AoA) into data to be used as estimation of cell change. Currently, the MME sends search signals to all base stations in the vicinity of the mobile station to determine to which cell the mobile has moved, this process leads to an overload of the data
    network in the vicinity of the end user. In the system proposed in this work, determining the
    angle of arrival allows estimating where the mobile unit moves, and it is not necessary to
    activate all stati ons in the vicinity of the current station. This proposal is innovative and this is
    the main contribution of this work. Additionally, with the angle of arrival signal information,
    the base station may direct the signals to the mobile station thereby enabli ng a software
    defined coverage area. The theoretical development of the angle of arrival technique was
    confirmed in the tests carried out at the Telecommunication Laboratory of UNIFEI. The
    experimental results obtained were very close to the analytical res ults. Finally, an electronic
    circuit was developed showing in real time the angle of arrival of the signal, demonstrating
    that the multipath does not invalidate the use of this system in internal environments.

5
  • LUIZ FELIPE PUGLIESE
  • Uma Estrutura Alternativa para a Parametrização no Controle Robusto ℋ∞ em
    Tempo Discreto

  • Leader : LUIS HENRIQUE DE CARVALHO FERREIRA
  • MEMBRES DE LA BANQUE :
  • CAIO FERNANDES DE PAULA
  • FERNANDO HENRIQUE DUARTE GUARACY
  • JEREMIAS BARBOSA MACHADO
  • KARL HEINZ KIENITZ
  • LUIS HENRIQUE DE CARVALHO FERREIRA
  • RENAN LIMA PEREIRA
  • Data: 27 juin 2019


  • Afficher le Résumé
  • In this doctoral thesis, an alternative structure is presented for the parameterization of all
    ℋ∞ controllers for plants described by any left coprime factorization with a generalized
    methodology for the discrete-time case. It is shown that from the generic method for
    the synthesis of the ℋ∞ admissible controllers, the non-strictly proper central controller
    and the strictly proper controller are obtained. It is also demonstrated that, from the
    normalized left coprime factorization from the perspective of the proposed framework, it
    is possible (i) to obtain both the discrete-time central controller and the strictly proper
    controller based on the optimization solution of two algebraic Riccati equations; (ii) to
    find the value of the bound of robustness (𝛾𝑚𝑖𝑛) which is directly related to the robustness
    of the controllers in order to show that the non-strictly proper controller its more robust
    than the strictly proper controller.
    The ℋ∞ robust stabilization methodology of plants represented by a description in coprime
    factors has received particular interest by the simplicity in its use and by the
    general nature it represents the uncertainty in that context. It is a methodology able
    to incorporate performance and robustness objectives to the uncertainties in the design
    approach.
    In order to investigate the applicability of the proposed thesis, the effectiveness of the
    developed framework and consequently of the designed discrete-time controller, simulations
    and practical experiments regarding the control of the position of metallic sphere of
    a prototype magnetic levitation designed by manufacturer QUANSER were carried out.

6
  • FÁBIO AUGUSTO DA SILVA ANTUNES
  • AUTORRESTABELECIMENTO DE SISTEMAS DE TRANSMISSÃO – APLICAÇÃO DO CONCEITO ASSISTED-HEALING EM CENTROS DE OPERAÇÃO A PARTIR DE SISTEMAS ESPECIALISTAS

  • Leader : PAULO MARCIO DA SILVEIRA
  • MEMBRES DE LA BANQUE :
  • BENEDITO DONIZETI BONATTO
  • DENIS VINICIUS COURY
  • KLEBER MELO E SILVA
  • PAULO MARCIO DA SILVEIRA
  • ROBSON CELSO PIRES
  • Data: 5 juil. 2019


  • Afficher le Résumé
  • Transmission system restoration after disturbances is a critical task performed by operators in operation centers, which requires agility and safety and is strongly influenced by human factors, such as pressure and stress. Important decisions must be made from a considerable amount of information received by the EMS / SCADA computer systems, and these are crucial to the success of equipment and interrupted loads restoration. In general, operation proceedings for restoration are used to guide the actions of operators, from single outages to general blackouts. These proceedings establish important aspects about the actions to be performed, and cover everything from the sequence of the restoration process, as well as the preconditions that must be observed before the execution of each maneuver. These proceedings are traditionally composed of several documents that must be evaluated and understood by the operators during the execution of the restoration process. Consequently, the time spent reading and understanding these proceedings impacts the restoration negatively. In addition, any evaluation or decision mistakenly taken may undermine the entire process of restoration. This thesis presents a detailed evaluation of the execution of the transmission systems restoration process, aiming at automation based on the Assisted-Healing concept. A tool developed specifically for the purpose of automating the actions performed by operators at operation centers in favor of the restoration will be presented. This prototype is able to obtain and process real-time information from the EMS / SCADA and compare it with the knowledge bases previously prepared and stored in the system itself, which contain all the rules and conditions to be verified prior to the execution of the restoration maneuvers. The prototype system is also capable of sending closing commands to circuit breakers, aiming at equipment restoration, respecting the topology and the existing operational restrictions. The design of this solution required a deep understanding of the different standards and modeling adopted in alarms, protection signals, operation proceedings, topologies and substation configurations, as well as the development of a strategy to minimize maintenance actions on the system when there are changes in operation proceedings or topological changes in the transmission system. Based on the Expert Systems philosophy, all required knowledge is stored in knowledge bases. The processing logics are part of the inference engine, and do not require maintenance, while knowledge bases require updating as the operation proceedings for restoration undergo updates. The effectiveness of the presented proposal was evaluated through the use of the prototype system in a simulation environment identical to the EMS / SCADA used by the Operators of the Cemig Generation and Transmission Operating Center, in which scenarios were created to reproduce simple and multiple equipment trips, involving transmission lines, power transformers and various other extra-high voltage equipment. The results obtained through the prototype system show that the proposed solution is reliable and appropriate to provide concise diagnostics and automatically perform restoration actions, both in major disturbances and in common day-to-day operation center outages.

7
  • LUCAS GUSTAVO ARANGO
  • Modelagem Economica e Regulatória do Impacto das Perdas Comerciais sobre o Mercado de Energia Elétrica

  • Leader : BENEDITO DONIZETI BONATTO
  • MEMBRES DE LA BANQUE :
  • ANDERSON RODRIGO DE QUEIROZ
  • BENEDITO DONIZETI BONATTO
  • EDSON DE OLIVEIRA PAMPLONA
  • MARCOS ROBERTO GOUVEA
  • MAURICIO CAMPOS PASSARO
  • RAFAEL DE CARVALHO MIRANDA
  • Data: 30 juil. 2019


  • Afficher le Résumé
  • There is a concern in countries all around the world regarding energy losses, where developing countries are the most affected mainly due to governance issues. Within this context, the main issue is in relation to the economic sphere with financial waste of billions of dollars per year in some countries of the world, since energy losses can impact additionaly in some cases, the quality of energy delivered to the consumer. Thus, the thesis seeks to analyze the economic impact of non technical losses, especially electricity theft, over the electricity market in relation to distribution power companies and consumers and the impact on the power quality of the affected system. The analysis is conducted through a socio-economic market model (TAROT – Optimal Tariff) and through simulations done by Matlab-Simulink for some analysis of the power quality. As the main focus of the thesis lies on the economic-regulatory issues of the electricity market agents, then the impact of non technical losses on the companies regulatory tariff will be examined, as well as the value of the optimal investment in technical and commercial quality for the company operate with minimum regulatory tariff. Finally, a risk study for some variables under uncertainty in a tariff review cycle, including non technical losses, will be conducted in order to present a methodology for calculation and determination of electricity companies regulatory tariff at risk conditions.

8
  • ROGÉRIO SALUSTIANO
  • Metodologia de Baixo Custo para a Avaliação do Comportamento de Envelhecimento de Isoladores Poliméricos

  • Leader : ESTACIO TAVARES WANDERLEY NETO
  • MEMBRES DE LA BANQUE :
  • ALAN MELO NÓBREGA
  • ALVARO ANTONIO ALENCAR QUEIROZ
  • ESTACIO TAVARES WANDERLEY NETO
  • GUSTAVO PAIVA LOPES
  • IVAN PAULO DE FARIA
  • JOSE FELICIANO ADAMI
  • Data: 16 août 2019


  • Afficher le Résumé
  • Polymeric insulators are increasingly being used in distribution system in Brazil. However, with its increasing use the occurrence of failures also intensifies. Despite the advantages that polymeric insulators bring to the network, factors such as difficult to determine lifetime, limited experience, difficult to monitoring and to diagnosis; greater susceptibility to damage from electrical activities and lower resistance to ultraviolet rays raise doubts during its use. To assess these factors and the quality of insulators, high cost processes and equipment are available today. Due to the cost to conduct standard tests both the analysis of polymeric insulators and their behavior during aging are avoided by companies (buyers and suppliers). Thus, this work aims to develop a low cost system that is capable of aging the polymeric insulators with the use of multiple stresses and to analyze the behavior of the samples during the aging process in order to present a method of aging with qualitative evaluation of sample quality based on physicochemical and electrical analysis. This work provides a better understanding of the mechanisms associated with the electrical degradation of polymeric insulators with humidity, rain, temperature and system voltage, improving the development of procedures for the acquisition of more reliable insulators. For this purpose, an aging chamber was developed, and aging cycles were performed on samples from manufacturers available in the national market. Aging of the samples can be analyzed by contact angle; Fourier transform infrared spectroscopy and thermogravimetric analysis and leakage current measurements. Finally, it was possible to prove the aging of the samples and the effectiveness of the developed chamber, as well as to evaluate the aging of the samples of each manufacturer.

9
  • BRUNO de NADAI NASCIMENTO
  • CONTROLE SECUNDÁRIO ALIADO AO CORTE DE CARGA PARA MICRORREDES EM CONDIÇÕES OPERATIVAS DE ILHAMENTO

  • Leader : ANTONIO CARLOS ZAMBRONI DE SOUZA
  • MEMBRES DE LA BANQUE :
  • ANTONIO CARLOS ZAMBRONI DE SOUZA
  • ELIANE VALENCA NASCIMENTO DE LORENCI
  • JOAO GUILHERME DE CARVALHO COSTA
  • JULIO CESAR STACCHINI DE SOUZA
  • PEDRO PAULO BALESTRASSI
  • ROMEU REGINATTO
  • Data: 11 oct. 2019


  • Afficher le Résumé
  • The evolution of current electrical systems is notorious when compared in the last years. This evolution is mainly due to the emergence of the smart-grids concept, giving increased access to the penetration of distributed resources at the level of energy distribution. In this context, microgrids are increasingly emerging as a potential solution to combine reliability, quality, and sustainability in the supply of electricity. Since there is a possibility of a microgrid operates in isolation from the main network, special attention should be given to this issue. In this way, the MGCC plays a vital role in the survival of the system, managing all the resources of the agents to guarantee safe operation and within the standards of supply demanded by the regulatory agencies.
    In this Ph.D. thesis, the whole theoretical basis of microgrids is presented, giving evidence mainly to the problem of islanding regarding the variation of demand, which in many cases, can cause a point of operation unfeasible due to the inherent variability of demand. To correct the operation, a unified secondary voltage and frequency control strategy in the process of power flow convergence is proposed. In addition, taking into account the limitation of the available resources, the load shedding becomes an emergency approach, preserving the operation limits and the continuity in the supply of electricity to essential services. Finally, an analysis within the concept of voltage stability is also presented with the purpose of assisting in decision making. This analysis shows the relation of the degree of system supportability related to the converters operation mode and their generation limits, both in the connected and islanded systems operation.
    The results from the tools proposed here are validated and discussed based on the IEEE 37-Nodes Test Feeder system, when modifications are made to make it equivalent to a micro network.
    Thus, in an islanding scenario, it is expected that MGCC with the tools developed here will be to manage all resources by predicting demand variability and before the system experiences any non-feasible operating point, regardless of the load and penetration scenario. renewable resources.

10
  • CRISTIAN ADOLFO ALVEZ
  • Allocation of Photovoltaic Generators in Power Systems

  • Leader : ANTONIO CARLOS ZAMBRONI DE SOUZA
  • MEMBRES DE LA BANQUE :
  • ADRIANO BATISTA DE ALMEIDA
  • ANTONIO CARLOS ZAMBRONI DE SOUZA
  • ELIANE VALENCA NASCIMENTO DE LORENCI
  • MIGUEL CASTILLA
  • PEDRO PAULO BALESTRASSI
  • RAFAEL CORADI LEME
  • Data: 11 nov. 2019


  • Afficher le Résumé
  • Demand growth promotes the connection of distributed generation in electrical systems as an option to meet demand locally. This can bring important benefits in addition to demand reduction, such as reduction of losses and environmental impacts. However, the integration of distributed generation, especially those based on renewable resources, presents several technical and economic challenges. One of the main challenges of the integration of renewable generation is the randomness of the operation, which exposes the system operator to situations of economic risk, especially when considering high levels of penetration. Thus, this motivates the development of planning tools to explore the impact of randomness on the system operation. This work presents models for allocating photovoltaic generators into power systems. Three objectives are explored in the allocation. On the one hand, the minimization of active power variance in the substation of distribution systems. On the other hand, the minimization of the variance of the operating cost in transmission systems. Finally, the maximization of the hosting capacity in radial networks it also addressed. The mathematical formulation is based on optimized stochastic power flow models that allow to define the photovoltaic modules allocated in each bus of the system. To validate the performance of the models, simulations with distribution and transmission systems were performed, using time series of solar radiation and demand. The results show that the methodology can reduce the variance of the operating cost when applied to transmission systems. Moreover, the model proved effective in integrating high levels of photovoltaic generation into distribution systems, without causing significant violations in the operating limits.

11
  • ELCIO DECCACHE
  • Agent-based modeling of a customer's consumer decision in a regulated electricity market where electric energyis stolen

  • Leader : BENEDITO DONIZETI BONATTO
  • MEMBRES DE LA BANQUE :
  • ANDERSON RODRIGO DE QUEIROZ
  • BENEDITO DONIZETI BONATTO
  • FERNANDO NUNES BELCHIOR
  • MOISES DINIZ VASSALLO
  • VICTOR EDUARDO DE MELLO VALERIO
  • Data: 5 déc. 2019


  • Afficher le Résumé
  • Investments in markets that are regulated monopolies are often safe investments. This is due to the assurancethat the monopoly regulation offers to the remuneration of the investment. However, when external factors not well considered in regulation occurs with regularity (such as energy theft), this guarantee disappears. The return on investment may not be the expected (and may suffer positive or negative variations). This paper presents an economic agent-based modeling of a customer’s consumption decision in a regulated electricity market where there is power theft.The economic model of the agent-based electricity market allows us to assess the optimal number of technical inspections to be performed to minimize the occurrence of power theft. The proposed methodology was applied to a test case considering typical data from a regulated electricity distribution company. The goal is not to identify the individual who steals energy, but actions to curb the theft. They are presented and discussed the results showing the evolution of the economic variables of interest to the problem. The proposed methodology has potential for application in the electric sector. Based on the consumption decision model of customers and the electricity sector, it was possible to evaluate the points of interest of different actors in order to understand how their interests behave.

12
  • CARLOS EDUARDO TEIXEIRA
  • Monitoring System of Moisture Contamination in Fuel Oils through Ultrasound Signal Analysis

  • Leader : LUIZ EDUARDO BORGES DA SILVA
  • MEMBRES DE LA BANQUE :
  • CAMILA PAES SALOMON
  • ERIK LEANDRO BONALDI
  • GISCARD FRANCIMEIRE CINTRA VELOSO
  • LEVY ELI DE LACERDA DE OLIVEIRA
  • LUIZ EDUARDO BORGES DA SILVA
  • Data: 6 déc. 2019


  • Afficher le Résumé
  • The generation capacity of thermoelectric plants depends directly on the quality of the fuel oil used. Besides reducing the efficiency, fuels containing high levels of contaminants may jeopardize the system itself and also the environment. Due to damage caused when it is in contact with other contaminants (e.g., sulfur), added to the ease of adulteration by the simple addition of it, water, the universal solvent, becomes one of the most critical contaminants. Thus, for the analysis of fuel oil, thermoelectric plants usually counts on laboratory tests. Although this approach offers good precision and good detail about the presence of contaminants, long periods of time are required until results are obtained. Upon such preliminary information, this work aims to analyze the moisture contamination of fuel oil samples by emitting, receiving and analysing ultrasonic signals. In order to identify the levels of contamination and classify the different fuel oil samples, the approach implements the Principal Component Analysis (PCA). This methodology leads to an expression that relates the score value issued from PCA and the water/oil ratio information, allowing the online application of the developed system and, consequently, reducing the time to obtain the desired information. The prototype used in this work was fully developed, guaranteeing versatility for all tests and adjustments made. We could also compare the proposed system with a capacitive sensor under field conditions. We verified a maximum difference of 0.2 percentage point between both approaches.

13
  • DANIELY GOMES SILVA
  • Transformation Optics for Obtaining Quasi-Conformal Mapping in Three-Dimensional Invisibility Cloaks

  • Leader : DANILO HENRIQUE SPADOTI
  • MEMBRES DE LA BANQUE :
  • CARLOS ALBERTO DE FRANCISCO
  • DANILO HENRIQUE SPADOTI
  • EDUARDO HENRIQUE SILVA BITTENCOURT
  • JOSE ANTONIO JUSTINO RIBEIRO
  • LUCIA AKEMI MIYAZATO SAITO
  • MATEUS AUGUSTO FAUSTINO CHAIB JUNQUEIRA
  • Data: 9 déc. 2019


  • Afficher le Résumé
  • The transformation optics technique, achieved through coordinates transformation, is used to control electromagnetic waves propagation, enabling new applications using complex optical devices. The invisibility cloak stands out as the most recognized application in the transformation optics field, due to its ability to make objects invisible to an external observer. A particular case of the invisibility cloak is the carpet cloak, which has attracted greater attention because it presents simpler development, by reducing complexity and constraints imposed by the free space cloak. However, in order to obtain the desired wave propagation control, the transformation optics presents some challenges, such as anisotropic and non-homogeneous permeability and permittivity tensors, or refractive indexes with negative values. An alternative for feasibly applying the transformation optics, discussed in this work, is the use of quasi-conformal mapping, minimizing the inherent complexity of the transformation optics. It results in propagation medium with broadband operation and reduced anisotropy. Different methods will be presented to obtain this type of mapping, including mapping for cloaking three-dimensional objects. This work introduces a new approach for achieving quasi-conformal mapping in the development of a three-dimensional invisibility carpet cloak. This mapping will be obtained through parametrization and numerical optimization techniques, leading to anisotropy reduction, and enabling the use natural-only isotropic materials in its development. Through full-wave numerical simulations, it will be possible, for the first time, to demonstrate invisibility in any direction of wave propagation, regardless of the angle of incidence and the polarization of the electromagnetic wave. The operation of this device will theoretically be demonstrated in different frequency ranges, including in the visible light spectrum, showing its ability to operate with broadband response.

2018
Thèses
1
  • VINÍCIUS VELOSO ELEUTÉRIO NOGUEIRA
  • Planejamento de Missão para VANTs em Ambientes Estocásticos

  • Leader : LUIZ EDIVAL DE SOUZA
  • MEMBRES DE LA BANQUE :
  • LUIZ EDIVAL DE SOUZA
  • GUILHERME SOUSA BASTOS
  • LEONARDO OLIVI
  • Data: 30 nov. 2018


  • Afficher le Résumé
  • Os veículos aéreos não tripulados (VANTs) têm atraído a atenção das pessoas civis pelo
    seu crescente número de aplicações e pela redução de custos. A grande maioria das tarefas
    atuais do UAV ainda possui um baixo grau de autonomia, o que pode levar à falta de
    eficiência, segurança, viabilidade e praticidade. Neste trabalho é analisado o emprego de
    técnicas probabilística em planejamento automático para melhorar a autonomia e robustez
    nas aplicações de UAV. O trabalho contribui ainda com um sistema de planejamento
    probabilístico, denominado DOTPlan, que integra o planejador Prob-PRP em sistemas
    ROS. Este sistema permite a visualização, execução e monitoramento de seus planos com
    base no formato DOT, usando a Máquina de Estados Finitos para execução e uma representação
    gráfica por meio de grafos gerados automaticamente. Para realizar o estudo de
    viabilidade do uso do Prob-PRP, o 𝑓𝑟𝑎𝑚𝑒𝑤𝑜𝑟𝑘 desenvolvido é analisado em um domínio
    de entregas com VANTs. Por fim o sistema é incorporado no controle de missões de alto
    nível em um UAV autônomo simulado no Gazebo.

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