PRPPG32003013001D0 PRPPG - PÓS GRADUAÇÃO EM ENGENHARIA ELÉTRICA PRÓ-REITORIA DE PESQUISA E PÓS-GRADUAÇÃO Téléphone/Extension: Indisponible
Dissertation/Thèse

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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
  • 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.

3
  • VICTOR FERREIRA ZWETKOFF
  • Probabilistic Method for Transmission System Pricing Considering Intermittence of Wind Power Sources

  • 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.

4
  • 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.

5
  • 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.

6
  • 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.

7
  • 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.

8
  • 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.

9
  • CLAUDIO 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.

10
  • 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.

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.

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


  • Afficher le Résumé
  • 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 ELY 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.

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