Programa de Pós-Graduação em Engenharia Elétrica - PPGEE/ITEC

URI Permanente desta comunidadehttps://repositorio.ufpa.br/handle/2011/2314

O Programa de Pós-Graduação em Engenharia Elétrica (PPGEE) do Instituto de Tecnologia (ITEC) da Universidade Federal do Pará (UFPA) foi o primeiro e é considerado o melhor programa de pós-graduação em Engenharia Elétrica da Região Amazônica. As atividades acadêmicas regulares dos cursos de mestrado e doutorado são desenvolvidas principalmente nas Faculdades de Engenharia Elétrica e Engenharia de Computação, supervisionadas pela Coordenação do Programa de Pós-Graduação em Engenharia Elétrica (CPPGEE).

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Agora exibindo 1 - 9 de 9

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 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)
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)
Balanço energético de um laboratório de pesquisa em cenários pré, durante e pós pandemia, visando certificação NZEB
(Universidade Federal do Pará, 2022-06-27) LAVÔR, Matias Ribeiro Máximo de; LEAL, Adônis Ferreira Raiol; http://lattes.cnpq.br/4099411616990036
Photovoltaic systems have an essential role to improve the energy efficiency of buildings, so that when integrated, it works directly on the energetic balance, with a percentage of load to be compensated by the renewable energy source, important parameter according to latest efficiency requirements. National building labeling is already mandatory for federal buildings, demanding, among other requirements, the compliance of new procedure named Instrução Normativa Inmetro para a Classificação de Eficiência Energética de Edificações Comerciais, de Serviços e Públicas (INI-C), that replaced the old procedure named Regulamento Técnico da Qualidade para o Nível de Eficiência Energética de Edificações Comerciais, de Serviços e Públicas (RTQ-C). The new procedure brings criteria and methods for classifying energy efficiency for commercial, service and public buildings, aiming to obtain labeling buildings. The new instruction also includes the distributed generation in energetic balance of building, as well as the definition of NZEB buildings and carbon dioxide emissions evaluation method. Since 2020, the world has been experienced an exceptional period of the Covid-19 pandemic, and by changing the social dynamics, introduced temporary or permanent transitions in energetic balances and standards of buildings electricity consumption at the whole planet, due to geographic extension of pandemic effects. In this regard, this study seeks to present an analysis of the energetic balance in different chronological scenarios for the building named Centro de Excelência em Eficiência Energética da Amazônia (CEAMAZON), a public institution of Research, Development and Innovation, linked to UFPA, located in the Science Park and Technology of Guamá. Additionally, it shows a short analysis of the new INI-C related to the NZEB and carbon emissions evaluation methodology, considering the new implanted distributed generation system, and the electric vehicle charging station located nearby, highlighting the set of building characteristics that can classify its energy efficiency, and demonstrating essential parameters for certification.
Acesso aberto (Open Access)
Comparação entre métodos de fluxo de carga para redes de distribuição ativas
(Universidade Federal do Pará, 2018-12-04) AMARAL, Lucas Felipe; VIEIRA, João Paulo Abreu; http://lattes.cnpq.br/8188999223769913
This dissertation presents a comparative study of load flow methods for analysis of active distribution networks. The proposed study takes into account the changes already faced by distribution systems, such as a high penetration of distributed generation (DG), while considering the typical characteristics of distribution networks, as the high R/X ratios. These characteristics impose difficulties on the performance of both backward-forward sweep and decoupled-based power flow methods. On the other hand, modified algorithms based on the decoupled method, such axis rotation fast decoupled and fast decoupled via pu normalization, can be efficiently applied to distribution system analysis. Thereby, a comparison of performance in terms of number of iterations and computational effort is carry out between the following methods: Newton-Raphson, Current Summation, Axis Rotation Fast Decoupled and Fast Decoupled via Complex pu. Normalization. The performance of each method is analyzed for different DG penetration levels, DG modelled as PQ and PV buses, and different R/X ratios. In addition, the influence of the base angle of both decoupled methods on the number of iterations was analyzed. The methods were tested in four distribution systems: 2-bus system, IEEE 69-bus system, 476-bus system and 1080-bus system.
Acesso aberto (Open Access)
Estudo comparativo de métodos de filtragem para medições não-invasivas de descargas parciais em sistemas de alta tensão: abordagens com diferentes filtros clássicos, adaptativo e transformada wavelet.
(Universidade Federal do Pará, 2024-11-06) SILVA, Adriel Brito da; NUNES, Marcus Vinícius Alves; http://lattes.cnpq.br/9533143193581447; https://orcid.org/0000-0001-5079-4126
The Partial discharge (PD) phenomene occur in segmented manner in electrical insulation. Over time, these occurrences can evolve to a critical state, resulting in short circuits and significant damage to electrical equipment. PD detection and analysis are essential in the context of preventive maintenance, contributing to high availability rates of Electrical Power Systems (EPS). However, interference from various noise sources, such as other electrical equipment and electromagnetic phenomena, makes PD signal detection challenging. This work presents a comparative study of filtering and signal analysis methods in noninvasive measurements of partial discharges in real high voltage systems, using different classical filters and the Wavelet Transform (WT). The research evaluated the effectiveness of several filtering methods in noise reduction, providing better identification and characterization of PD signals. Classic filters such as Moving Average (MA), Butterworth (BW), Chebsyshev (Type I), SavitzkyGolay (SG) and adaptive filtering such as Least Mean Squares (LSM), in addition to techniques based on multiresolution wavelet decomposition, were implemented and compared to verify metrics such as Signal-to-Noise Ratio (SNR), Cross-Correlation (CC), Root Mean Square Error (RMSE), Kurtosis (K), and others, considering the preservation of the essential characteristics of PD signals. The results obtained demonstrated that filtering techniques are crucial for reducing noise effects, although more classical methods present limited efficiency when compared to those with adaptive capacity. The comparative analysis revealed critical points that, although they demonstrated restricted efficiency, contribute significantly to the improvement of electrical equipment monitoring methods.
Acesso aberto (Open Access)
Otimização da detecção de formas de onda de campos eletromagnéticos emitidos por descargas atmosféricas
(Universidade Federal do Pará, 2018-01-23) LEAL, Adônis Ferreira Raiol; RAKOV, Vladimir; ROCHA, Brigida Ramati Pereira da; http://lattes.cnpq.br/9943372249006341
This work aims the application of optimization techniques to detect and record lightning electromagnetic waveforms. As a result of the optimization techniques developed on this Thesis, it is presented the “Lightning Detection and Waveform Storage System - (LDWSS)”. The main optimized points were: cost of the device; improvements of its detection dynamic range; development of a mobile device; possibility to detect in a multi-band way; and calibration in order to infer peak currents from remote measurements of lightning electric fields. The developed system was validated through comparison of a return stroke data in lightning triggered using the rocket-and-wire technique at the International Center for Lightning Research and Testing - ICLRT, of National Lightning Detection Network – NLDN data, and data from the Lightning Observatory in Gainesville - LOG. The main usage of the optimized system is on the investigation of lightning physics and effects, mainly in the Amazon region. As a result of using the system were obtained: a better understanding about Compact Intracloud Discharge - CID; the characteristics of ionosphere heights computed using intraclound and cloud-to-ground lightning electric field waveforms; the conception of a lightning electric field waveform database containing more than 8 thousand waveforms of different types of lightning; and the implementation of the first continuous lightning electric field measurement system in the amazon region, localized at CESIPAM, Belem, PA.
Acesso aberto (Open Access)
Utilização de satélite geoestacionário para avaliar a incidência de raios em linhas de transmissão do sistema interligado nacional brasileiro
(Universidade Federal do Pará, 2024-07-24) MATOS, Wendler Luis Nogueira; LEAL, Adônis Ferreira Raiol; http://lattes.cnpq.br/4099411616990036; https://orcid.org/0000-0003-0606-2950
Lightning is responsible for the death of people and animals, in addition to damage to the electrical system, within the scope of distribution and transmission networks. One of the main parameters for evaluating the occurrence of lightning is the lightning density in a given region of interest. The GLM sensor, on board the GOES-16 geostationary satellite, allows continuous monitoring of the Americas. Through data processing, it is possible to plot the lightning density for any region within the field of view. The use of this data allows monitoring the occurrence of lightning, helping to identify regions at greater risk of damage associated with lightning. In the case of a large country like Brazil, that has many transmission lines with hundreds of kilometers, forming the National Interconnected System (SIN), it is essential to have updated and regionalized data. Data from the National Electric System Operator (ONS) were processed, and important information about the SIN lines was presented, such as the number of lines per voltage level and their lengths in kilometers, number of line failures per year, per month and by voltage level, as well as the percentage of each type of failure, noting that the main cause of failures is due to lightning, with 25%, being one of the points that supported the importance of this work. The objective of the dissertation is to provide updated lightning density data in the period 2019-2023 for all transmission lines belonging to Brazil's base power transmission network, at the following voltage levels: 230, 345, 440, 500, 525, 600, 765 and 800 kV. Maps were generated for each voltage level, and also a general map for the entire SIN and the entire Brazilian territory. The monthly amount of lightning was compared with the monthly number of faults, observing that the most critical periods of the year are the first and last quarter. Considering all transmission lines, the average lightning density was 11.74 lightning/km2/year, and for Brazil it was 13.17 lightning/km2/year, with a maximum value of 57.62 lightning/km2/ year. Furthermore, the average number of lightning, during the 5 years, was 46 million for the SIN lines and 98 million for Brazil. Finally, a very strong correlation was observed, with a coefficient of 0.91, between the monthly number of lightning and the monthly number of faults caused by lightning, during the observation period.

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