Dissertações em Engenharia Elétrica (Mestrado) - PPGEE/ITEC

URI Permanente para esta coleçãohttps://repositorio.ufpa.br/handle/2011/2316

O Mestrado Acadêmico inicou-se em 1986 e pertence ao Programa de Pós-Graduação em Engenharia Elétrica (PPGEE) do Instituto de Tecnologia (ITEC) da Universidade Federal do Pará (UFPA).

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Acesso aberto (Open Access)
Adequação do laboratório de alta tensão da UFPA - LEAT aos requisitos gerais para a competência de laboratórios de ensaio e calibração da norma ABNT NBR ISO/IEC 17025
(Universidade Federal do Pará, 2022-02-24) BRASIL, Alexandre de Souza; NUNES, Marcus Vinícius Alves; http://lattes.cnpq.br/9533143193581447
Phenomena that cause electrical imbalances in power systems occur constantly, which generates the need to study them in order to allow the development of electrical networks and equipment that behave more reliably and robustly in the face of such disturbances. These studies are generally carried out in specialized High Voltage and High Power laboratories. Over the years, the market started to demand that these studies also provide results that comply with quality standards certified by official bodies. In this sense, this dissertation aims to propose the necessary adaptation of the High and Extra High Voltage Laboratory of the Federal University of Pará (LEAT) to the requirements for the competence of testing and calibration laboratories defined by the ABNT NBR ISO/IEC 17025 standard, with a focus on development and implementation a Quality Management System; creation of operational procedures and safety guidelines; establishment of a calibration program for laboratory equipment; and identification of motivations, advantages and impacts related to the implementation of the requirements of that standard, as well as the difficulties and solutions found. For this, first, a literary survey was carried out that sought to know the national panorama of higher education institutions with accredited laboratories under the referred standard. Then, the process of implementing the requirements of the standard began, which was based on the methodology adapted from Grochau (2011). Finally, the lived experience allowed us to observe that the adaptation to the standard requirements in laboratories linked to public institutions, although complex at first, is fully capable of providing several benefits and advantages, as long as the peculiarities of this type of institution are respected, such as: bureaucracy; resource limitation; training of the personnel involved and; reconciling research and teaching activities with services provision.
Acesso aberto (Open Access)
Análise da metodologia para definição dos limites de continuidade dos conjuntos elétricos das distribuidoras de energia elétrica no Brasil
(Universidade Federal do Pará, 2024-10-10) OLIVEIRA, Loreddana Monteiro Bandeira de; TOSTES, Maria Emília de Lima; http://lattes.cnpq.br/4197618044519148
The definition of continuity indicator limits for electrical network sectors in electricity distribution companies represents the primary regulatory aspect of electricity supply quality, directly impacting consumer tariffs and investment decisions made by electric companies in electricity distribution systems. In the context of electricity sector regulation, maintaining continuity indices at appropriate levels is crucial to improving supply for consumers and ensuring tariff accessibility. This study presents the Brazilian regulation of collective continuity indicators for electricity supply, developed by the National Electric Energy Agency (ANEEL), from its implementation to the present, analyzing how each regulatory change has influenced the performance and development of the Brazilian electricity sector, with particular emphasis on the State of Pará. Pará exhibits unique continuity indicators compared to other states due to its concession area characteristics, including access challenges, long distances, and low population density. ANEEL uses benchmarking among distribution companies’ electrical sectors to establish performance targets at the end of each tariff cycle; however, the current method for setting regulatory limits does not account for factors that directly impact operational management or specific regional characteristics. This dissertation aims to analyze the current methodology for defining continuity limits for the electrical network sectors of electric companies in Brazil.
Acesso aberto (Open Access)
Análise de Desempenho de Meta-heurísticas Aplicadas ao Problema de Restauração de Redes de Distribuição.
(Universidade Federal do Pará, 2020-02-20) BATISTA, Vítor dos Santos; BEZERRA, Ubiratan Holanda; http://lattes.cnpq.br/6542769654042813
In the last years, several meta-heuristics have been used to solve the problem of restoring distribution systems efficiently. Among them, the Multiobjective Evolutionary Algorithm with Node-depth encoding (MEAN) stands out, which together with Node-Depth Encoding (NDE) makes a great advance in the field. All this because the NDE makes changes on the topology of the distribution system without losing radiality and reestablishing the power supply for all disconnected loads after the fault. Due to the lack of exploration of other meta-heuristics that use NDE as a data structure, this work aims to evaluate a performance analysis comparing MEAN with three other meta-heuristics, Tabu Search, Artificial Bee Colony and Evolutionary Strategies. The analysis was performed in three distribution systems the84-bus, 119-bus and 135-bus.s
Acesso aberto (Open Access)
Análise de desempenho de pará-raios de ZnO sob diversos cenários de poluição utilizando método de elementos finitos
(Universidade Federal do Pará, 2022-08-16) LISBOA, Mellina Modesto; NUNES, Marcus Vinícius Alves; http://lattes.cnpq.br/9533143193581447
Metal-Oxide Surge Arrester is one of the protection devices of vital importance for Electric Power Systems and the equipment that composes them, since it ensures the reliability and continuity of operation of these systems based on their ability to attenuate transient overvoltage resulting from lightning strikes or switching surges. This equipment is formed by blocks of variable ZnO resistors, associated in series or in parallel, whose voltage-current curve presents high non-linearity. In view of the relevance of using the lightning rod, it is necessary to investigate its operating conditions. In the literature, several procedures and techniques are found for this purpose, among which monitoring through measurement and analysis of the leakage current stands out, since this represents one of the main factors that contribute to the degradation of this equipment. Given this context, the present master's dissertation implements a two-dimensional model of a 30 kV Zinc Oxide lightning arrester, using the Finite Element Method, to obtain the leakage current curves, electrical potential distributions, current density and that of electric field lines, when this device is subject to voltage variations and pollution conditions. The results show a significant increase in these measured quantities as the level of pollution intensifies, as well as with the increase in voltage levels.
Acesso aberto (Open Access)
Análise de estabilidade transitória em geradores distribuídos: considerações sobre a proteção 78PS.
(Universidade Federal do Pará, 2024-09-09) HERINGER, Wesley Rodrigues; NUNES, Marcus Vinícius Alves; http://lattes.cnpq.br/9533143193581447
This dissertation aims to present the transient stability analysis in Distributed Generators, considering the performance of 78PS protection, against loss of synchronization. In this context, the studies developed in this work will be considered For two distinct real cases of two cogeneration plants with synchronous generators of different powers, being a sugar-alcohol plant, which will soon be connected to An extensive rural feeder of Equatorial Energia’s Paragominas 34.5 kV substation, being in the second case analyzed a fruit pulp industry that uses biomass Resulting from the processes as fuel for the steam boiler, which connects to the a turbine, to drive a generator. In turn, this system will be interconnected in a predominantly urban feeder, in a distribution substation of 13.8 kV at Castanhal in the interior of Pará. The analyses are carried out by means of complete simulation in the time domain through software Anatem© , considering two modes of voltage control of synchronous machines: 1) without voltage control; and 2) with voltage control. The studies provide the margins of transient stability of the machines and considerations on the protection against the loss of timing of synchronous generators. The results indicate that the use of the voltage control mode of the automatic voltage regulator and the coordination between the protection of the internal feeders of the industrial consumer and the protection of the plant are fundamental to ensure the maintenance of the timing of distributed generation.
Acesso aberto (Open Access)
Análise de modelos, simulações e ensaios de impulso em um transformador de distribuição.
(Universidade Federal do Pará, 2019-03-12) CARDOSO, Antonio Fernando Martins; NUNES, Marcus Vinícius Alves; http://lattes.cnpq.br/9533143193581447
Acesso aberto (Open Access)
Análise de supraharmônicos em equipamentos eletrônicos e caracterização utilizando a transformada wavelet
(Universidade Federal do Pará, 2018-09-10) RODRIGUES, Carlos Eduardo Moreira; TOSTES, Maria Emília de Lima; http://lattes.cnpq.br/4197618044519148
Esta dissertação objetiva analisar a emissão, a propagação e a interação entre equipamentos envolvendo componentes harmônicas que possuem frequência na faixa entre 2 kHz e 150 kHz, denominadas supraharmônicos. A literatura especializada já reportou a emissão de supraharmônicos por equipamentos eletrônicos como lâmpadas fluorescentes, lâmpadas LED, inversores de frequência e nobreaks, além de impactos relacionados ao aquecimento de cabos e terminações, ruído acústico e interferência em sistemas PLC (Power Line Communication). No presente trabalho, foram realizadas campanhas de medição, em ambiente laboratorial, em inversores de frequência e um conjunto de lâmpadas LED. As medições se dividiram em dois grupos distintos: com os equipamentos conectados à rede elétrica e a uma fonte eletrônica trifásica, com o objetivo de verificar as ordens e os níveis, tanto das emissões provenientes dos equipamentos, quanto da distorção emitida pela própria fonte eletrônica, além da interação entre a fonte e os equipamentos alimentados. Foram empregadas a Transformada de Fourier e a Transformada Wavelet Packet para efetuar a análise e caracterização das distorções observadas. As medições mostraram uma contribuição significativa dos equipamentos observados e da fonte eletrônica para a emissão de supraharmônicos, além da amplificação da distorção quando os equipamentos são por ela alimentados.
Acesso aberto (Open Access)
Análise do impacto de geradores fotovoltaicos na estabilidade transitória de geradores síncronos distribuídos
(Universidade Federal do Pará, 2018-02-19) PINHEIRO, Wanessa Tâmiris de Souza; NUNES, Marcus Vinícius Alves; http://lattes.cnpq.br/9533143193581447
This dissertation aims to present a comparative analysis between two models of inverter control for the study of the transient stability analysis and voltage stability, with the insertion of the photovoltaic generation in the distribution electric grid. It is also proposed an analysis of the influence, both negative and positive, caused by the control modes of these inverters in the stability of synchronous machine connected to the grid. Another proposed solution to be investigated in this work will be the use of the reactive power control mode of photovoltaic generators via the inverter, which can contribute to the relief of the reactive demand of distributed synchronous generators interconnected in the same electric system, in order to reduce the possibility of generating a voltage instability condition, after a big disturbance, or in the occurrence of contingencies in the electric power system that may affect weak or overloaded electrical grids and with large insertion of photovoltaic generators. The analysis of the control models will be carried out through simulations in the time domain, through the ANATEM and ANAREDE computational tools.
Acesso aberto (Open Access)
Análise dos impactos harmônicos na qualidade da energia elétrica utilizando kdd – estudo de caso na Universidade Federal do Pará
(Universidade Federal do Pará, 2019-03-18) SILVA, Waterloo Ferreira da; TOSTES, Maria Emília de Lima; http://lattes.cnpq.br/4197618044519148
The present work presents an analysis of data related to Power Quality (PQ), the increasing use of nonlinear loads, equipment based on power electronics in residential, commercial and industrial installations are contributing to the significant increase in the levels of harmonic distortion of current and, consequently, of voltage, as observed in the Brazilian electricity distribution system. It was developed in Brazil, the distribution procedures in the national electricity system (PRODIST), created and developed by the National Electric Energy Agency (ANEEL). PRODIST aims to standardize and standardize activities related to energy distribution, including product quality standards. In order to monitor the quality of the product "electric energy" through the harmonic content generated by the electric network of the institution, a methodology is proposed for the analysis using computational intelligence (CI) and data mining techniques to analyze the data collected by meters of energy quality installed in the main sectors of this institution and at the point of common coupling of the consumer and consequently establish the relationship between the harmonic currents of the nonlinear loads with the harmonic distortion at the common coupling point. The KDD process was applied, including the collection, selection, cleaning, integration, transformation and reduction, mining, interpretation and evaluation of the data, in order to monitor the quality of the product "electric energy" through the harmonic content generated by the electric grid. educational institution. In the "Data Mining" data mining phase, the Naive Bayes classifier was used. The obtained results showed that the KDD process has applicability in the analysis of the Total Harmonic Distortion of Voltage at the Common Coupling Point and can be applied in any commercial, residential and industrial area.
Acesso aberto (Open Access)
Análises multifísica via método de elementos finitos para o auxílio à manutenção preditiva em transformadores de potência.
(Universidade Federal do Pará, 2018-09-21) SOUSA, Antonio Roniel Marques de; NUNES, Marcus Vinícius Alves; http://lattes.cnpq.br/9533143193581447
The National Interconnected System (NIS) is an organ of fundamental importance in the Brazilian panorama. Its function is to electrically connect generating centers and consumer centers, whether they are business, commercial or residential. The main equipment responsible for the connection and transmission of electric power from the generating centers to the consumers are the power transformers. This equipment is subject to several types of faults that can affect its components, in some cases compromising the operation of this equipment, and consequently the supply of electric energy. In this work, a multiphysical analysis is performed on power transformers, coupling thermal and structural electromagnetic simulations with the objective of providing the operator with information about the ideal moment for performing predictive maintenance, avoiding unplanned shutdowns. For this, computational simulations using the Finite Element Method (FEM) were used and from this, we analyzed the different situations that these equipments can be submitted, in the nominal condition, as well as extreme conditions of operation like current of inrush and current short-circuit. In this perspective, analyzes of the effects that the thermal expansion and the axial forces and radia exerted contributing to possible defects in these equipments were carried out. As a study object, the simulations were performed in a 50 MVA single-phase transformer, which is an equipment that is in operation in the northern region of the country. For a more validation of the methodology used in this work the simulations were validated with real measurement data and with results present in current literature. In this way, this work presents a methodology that can help the technical framework of an industry in the decision of the appropriate moment of stop in a power transformer for the accomplishment of predictive maintenance.
Acesso aberto (Open Access)
Analysis of classical and advanced control techniques tuned with reinforcement learning
(Universidade Federal do Pará, 2023-09-01) SILVA, Daniel Abreu Macedo da; SILVEIRA, Antonio da Silva; http://lattes.cnpq.br/1828468407562753
Control theory is used to stabilize systems and obtain specific responses for each type of process. Classic controllers, such as the PID used in this research, are spread globally in industries because they have well studied topologies in the literature and are easily applied in microcontrollers or programmable lógic devices; advanced ones,such as GMV, GPC and LQR, also used in this work, have some resistance in common applications in base industries, but are widely used in energy, aerospace and robotic systems, since the complexity and structure of these methods generate robustness and reach satisfactory performances for processes that are difficult to control. In this work, these methods are studied and evaluated with a tuning approach that uses re inforcement learning. The tuning methods are used in two forms and are applied to the controllers, these are the Repeat and Improve method and the Differential Games method. The first works using offline iterations, where the process agent is the chosen control technique, which selects performance and robustness indexes as an environment (metric of how the process is evolving), being able to organize an adjustment policy for the controller, which is based on rewarding the weighting factor until reaching the process stopping criterion (desired response). The second method uses reinforcement strategies that reward the controller as the response changes, so the LQR learns the ideal control policies, adapting to changes in the environment, which allows for better performance by recalculating the traditional gains found. With the Ricatti equation for tuning the regulator; in this method, differential games are used as a framework to model and analyze dynamic systems with multiple agents. To validate what is presented, the Tachogenerator Motor and the Ar Drone have been chosen. The Tachogenerator Motor is modeled with least squares estimation in an ARX-SISO topology, in order to evaluate the first tuning method. The Ar Drone is modeled with a state space approach to evaluate the second tuning method.
Acesso aberto (Open Access)
Aplicação de método de reconstrução de sinais baseado em decomposição variacional de modos no processamento de sinais de descargas parciais
(Universidade Federal do Pará, 2024-09-23) ALMEIDA, Vanilze Vaz Monteiro de; NUNES, Marcus Vinícius Alves; http://lattes.cnpq.br/9533143193581447
High-voltage equipment in electrical systems is subject to electrical insulation degradation, which promotes the evolution of partial discharge activity (PDs), a key factor in operational failures of these assets, resulting in significant losses. Therefore, the analysis of PD signals for accurate representation of operational conditions is essential, as it aids in making assertive decisions in predictive maintenance of equipment, as well as understanding their impacts. The procedure for acquiring PDs involves measurements using invasive or non-invasive devices, which show the occurrence of this phenomenon under field or laboratory operating conditions. However, this acquisition is subject to interference, leading to PD signals embedded in noise, which may arise from the electromagnetic nature of the equipment used or from external sources. This highlights the need to implement noise reduction and signal reconstruction techniques that ensure good representation of PDs, allowing for precise analysis by minimizing the loss of signal characteristics for further studies. Thus, in this work, a study was conducted on four noise reduction techniques for PD signals: Variational Mode Decomposition (VMD), Adaptive Filtering with Least Mean Squares algorithm (LMS), Wavelet Transform with Hard Thresholding (HTWT), and Wavelet Transform with Soft Thresholding (STWT), for reconstructing real PD signals obtained from measurements with High-Frequency Current Transformer (HFCT). The results from the signal filtering process were evaluated using metrics such as Root Mean Square Error (RMSE), Signal-to-Noise Ratio (SNR), and Correlation Coefficient (CC), demonstrating the importance of filtering methodology with the incorporation of VMD and the variation of parameters and filtering sequences established.
Acesso aberto (Open Access)
Augmentação estocástica com horizonte de predição estendido baseada no PID para um sistema multivariável
(Universidade Federal do Pará, 2019-10-25) CRUZ, Jahyrahã Leal dos Santos; SILVEIRA, Antonio da Silva; http://lattes.cnpq.br/1828468407562753
The objective of this research was to investigate and design a control system based on the Stochastic Augmentation with Extended Prediction Horizon using 10-steps ahead, consisting of the union of characteristics of a linear deterministic controller with a stochastic predictive controller, resulting in a control system with guaranteed robustness and with predictive, linear, and stochastic characteristics. For the application of the Stochastic Augmentation, the chosen controllers were the classic PID and the GMV in its incremental form, where the former was augmented resulting in a controller with extended prediction horizon, the AEHP. The classic PID controller in the discrete time domain is compared to AEHP. Both controllers were tested in simulations with a process model that represents the dynamics of a helicopter, denominated 2DOF Helicopter (H2DOF), produced by the Quanser company. The H2DOF is a multivariable system, whose model in the state space is transformed to the transfer function form, generating two coupled subsystems, one for the pitch angle and other to the yaw angle, in which the couplings influence were considered as disturbances in the controllers design stage. The transformation of the system model to the transfer function form reduced the complexity of multivariable system in the state space, allowing the use of a more simple control law. Furthermore, it was performed the pairing of input and output, to verify what output was more sensible the one specific input, by means of Relative Gain Array. And to prove the control system efficiency based in the Stochastic Augmentation with extended prediction horizon, simulations were realized using the software Matlab®, assessing the performance of extended prediction horizon, enduring the coupled dynamics, facing load disturbances and Gaussian disturbances. The essays were evaluated by robustness and performance indices. The predictive AEHP controller obtained better results for most indices with guaranteed robustness, compared to the discrete-time PID controller.
Acesso aberto (Open Access)
Avaliação da influência da configuração de controladores de carga no desempenho de geradores fotovoltaicos suprindo uma nanorrede de distribuição em corrente contínua
(Universidade Federal do Pará, 2022-09-09) ALBUQUERQUE, Luana Oliveira de; MACÊDO, Wilson Negrão; http://lattes.cnpq.br/3386249951714088
This thesis presents an evaluation of photovoltaics generators productivity, using different configurations charge controllers used in isolated system, which them are interconnected and constituted a distribution nanogrid in direct current. To support the research, there is a contextualization of the microgrids uses and the presentation of the nanogrid employed, which it is installed in the test area of Group of Studies and Development of Energy Alternatives (GEDAE) of Federal University of Pará. Throughout the thesis, the main equipments responsible for the formation of this network are indicated, as the charge controllers, associated with energy storage systems and photovoltaic generators. Different configurations from those recommended by the manufacturers are adopted, but within acceptable limits, in order to increase the productivity of photovoltaic generators and reduce losses. According to the results, when only one generation and storage system were in operation, it was observed an increase in generation productivity and a decrease in losses; when the nanogrid with all systems in operation was analyzed, with different configurations, it was observed a reduction of losses per capture, but the increase of productivity did not appear in the analysis because of exchange of energy presents in the nanogrid
Acesso aberto (Open Access)
Avaliação de algoritmos evolucionários multiobjetivo para o problema de alocação de bancos de capacitores na presença de harmônicos
(Universidade Federal do Pará, 2017-08-10) KATAOKA, Vitor da Silva; BEZERRA, Ubiratan Holanda; http://lattes.cnpq.br/6542769654042813; TOSTES, Maria Emília de Lima; http://lattes.cnpq.br/4197618044519148
The rapid growth of urban areas bring, as a consequence, an increase in the amount of loads connected to the distribution grids. Furthermore, the increase in the demand implies in equal raise in reactive loads, which are known to cause losses in the network. Thus, the utilities have a great challenge ahead, as the dynamics of the load require a greater effort in terms of expansion and improvements of the grid. In an attempt to mitigate the problems caused, the allocation of capacitor banks can become a practical, economical and technically robust solution. Nevertheless, it is extremely important to analyze the sizing and positioning of the banks, in order to achieve the best possible outcome. In parallel, the increasing use of nonlinear loads cause harmonics to appear in the system. When in conjunction with capacitor banks, it is possible to develop the far more dangerous phenomenon of resonance, where the amplitude of some of the harmonics goes beyond acceptable limits, resulting in undesirable effects. In this context, this work proposes a comparison between two multiobjective optimization tehcniques, NSGA-II and SPEA2, to solve the problem of sizing and placement of capacitor banks in electric energy distribution grids, considering the effects of harmonics produced by nonlinear loads.
Acesso aberto (Open Access)
Avaliação de desempenho operacional de microgeração e minigeração solar fotovoltaica em edificação comercial, industrial, residencial e pública no Estado do Pará
(Universidade Federal do Pará, 2022-11-18) MONTEIRO, Weslley Leão; MACÊDO, Wilson Negrão; http://lattes.cnpq.br/3386249951714088
This work evaluates the operational performance of different Photovoltaic Systems Connected to the Electric Grid, installed in 5 (five) consumer units, four in the metropolitan region of Belém/PA and one in Santarém/PA, consumption class: Residential, Commercial, Industrial and Public, in order to contribute to the construction of scientific knowledge and make public performance values of photovoltaic generators connected to the conventional grid in the North region of the country. For this, the electricity production data provided by the online monitoring platform of the grid connection inverter of each SFCR, in the years 2019 to 2021, was considered for the calculation of the merit indexes. monitoring, the data presented on the inverter display was considered. To calculate the final yield (YF) of two systems, the value of the real power of the photovoltaic generator was considered through I-V curve tests carried out in real sun with a curve tracer (Solar IVe) provided by GEDAE/UFPA, considering measurements performed in an arrangement of a subsystem. For the estimated performance ratio calculation, the Meteonorm v8.0 database was considered to obtain irradiation in the GFV plane. The results obtained in this work allow comparing the estimated global performance of the systems, making it evident that the operational results are directly related to the solution implemented in each system, to good practices during installations, and the importance of a more rigorous and continuous control of the SFCR monitoring.
Acesso aberto (Open Access)
Avaliação do desempenho das funções de controle volt-watt e volt-var em inversores fotovoltaicos integrados nas redes de distribuição
(Universidade Federal do Pará, 2018-03-27) WANZELER, Tiago Machado; VIEIRA, João Paulo Abreu; http://lattes.cnpq.br/8188999223769913
This dissertation addresses some of the major operational problems faced by distribution system operators due to the high integration of photovoltaic (PV) generators, such as overvoltages and excessive tap counts in step voltage regulators (SVR). These situations are continually being studied, since they can cause voltage quality problems and damage in SVRs. The overvoltage problem can be caused by a significant injection of active power from the PV generation to the network. Moreover, the rapid and significant variations in PV generator active power associated with cloud transients result in an increase of voltage regulator tap counts, which can affect the useful life of device. In this context, the smart inverters Volt-Watt and Volt-Var control functions have been added in recent studies to mitigate the overvoltages. This work shows how Volt-Watt and Volt-Var control functions mitigate the overvoltage and voltage regulation problems in distribution networks with PV generation. Time series power flow simulations on LV and MV single feeders with PV solar plant have been performed in high and low solar variability scenarios.
Acesso aberto (Open Access)
Avaliação do impacto econômico da conexão de veículos elétricos e da geração eólica em redes inteligentes de energia
(Universidade Federal do Pará, 2018-02-26) VIEGAS, Marcel Augusto Alvarenga; NUNES, Marcus Vinicius Alves; http://lattes.cnpq.br/9533143193581447; AFFONSO, Carolina de Mattos; http://lattes.cnpq.br/2228901515752720
This master dissertation presents a power management tool of a power system operating in a Smart Grid that contains Electric Vehicles inserted as loads and Wind Power Generation. The optimization technique used was Simulated Annealing, in order to minimize the total energy cost of the network being studied. Three charging strategies were adopted: Peak Charging, Off-peak Charging and Smart Charging besides Demand Side Management techniques. In addition to the charging process will also be studied the Discharging of the battery electric vehicles, preferably at the peak of the load curve, as well as the possibility of supplying grid power through the wind farm to supply both loads in the topology of the system as for the loads of electric vehicles inserted through the creation of a charging/ discharging station. The system used is the IEEE - 39 bus New England power system. The results proved the effectiveness of the proposed method and the importance of considering besides distribution as well as generation and transmission in studies of planning, expansion, and operation of Smart Grids that contain Electric Vehicles and Wind Power Generation.
Acesso aberto (Open Access)
Avaliação dos impactos da recarga de veículos elétricos na vida útil de transformadores de distribuição
(Universidade Federal do Pará, 2023-10-30) BARROS, Amanda Monteiro Pinto; AFFONSO, Carolina de Mattos; http://lattes.cnpq.br/2580696185627481
The objective of this dissertation is to provide a comparative assessment of the impacts caused by charging practices of short-range and long-range electric vehicles under different power levels on life expectancy of distribution transformers. This research is based on the use of real data of residential energy consumption collected from the region of East Midlands, United Kingdom, as well as electric vehicle charging data collected through an experimental project also conducted in the United Kingdom. This study examines transformer hottest-spot temperature and evaluates the transformer accelerated aging factor that influences the equipment's lifespan according to the thermal model presented in IEEE Standard C57.91. As a result, this study reveals that the effects caused by long-range vehicles are more pronounced, as they charge at higher power level and the charging process is longer. As the penetration level of electric vehicles increases, transformer load and hottest-spot temperature increases, especially during winter season, where residential demand escalates. In the case of vehicles with 75 kWh, penetration levels starting from 30% already causes severe violations on transformer hottest-spot temperature, contributing to a reduction in the equipment's lifespan.
Acesso aberto (Open Access)
Avaliação operacional dos efeitos do perfil de demanda de quatro sistemas de microgeração fotovoltaica conectados à rede
(Universidade Federal do Pará, 2018-06-29) PARIJÓS JÚNIOR, Ivan Ruy de; PEREIRA, Edinaldo José da Silva; http://lattes.cnpq.br/9596575345034065; MACÊDO, Wilson Negrão; http://lattes.cnpq.br/3386249951714088
Power quality has been widely researched. Several phenomena that affect power quality, and its consequences, have been investigated. When the power quality theme involves the operation of a grid-connected photovoltaic system, the main concern is about the operation of the inverter, which is responsible for the interface of the photovoltaic generator with the grid. The introduction of photovoltaic generation in the grid requires attention on certain factors such as changes in the load curve, voltage level, harmonic components in the inverter current and variation on the power factor (PF) of the costumer. This work aims to test and evaluate some aspects that may influence the power quality due to the insertion of photovoltaic generation in the grid, associated whit the load demand. Four grid-connected photovoltaic systems were used to develop this work, as well as a data acquisition bench that was set up to monitor the operation of these systems. In this work it is possible to conclude that the operation of photovoltaic systems causes changes in the voltage level at the point of common coupling. Also, the interaction between photovoltaic systems and loads causes changes in the load profile measured by the side of the grid, causing the total harmonic distortion in the current (THDi) and PF measured at this side to be different from those measured at the loads and photovoltaic sides. It is possible to observe that the grid-connected photovoltaic system can contribute to increase or reduce the THDi seen by the local grid, where the greatest contribution of harmonic distortion in the current delivered by the grid is associated to the demand profile of the load.