Engenharia Elétrica (UACSA)
URI permanente desta comunidadehttps://arandu.ufrpe.br/handle/123456789/2922
Siglas das Coleções:
APP - Artigo Publicado em Periódico
TAE - Trabalho Apresentado em Evento
TCC - Trabalho de Conclusão de Curso
Navegar
35 resultados
Resultados da Pesquisa
Item Previsão de consumo de energia elétrica no brasil: uma comparação entre métodos(2023-09-22) Fortes, Bruna Lavínia Santos; Ferreira, Felipe Alberto Barbosa Simão; http://lattes.cnpq.br/9939255113143786; https://lattes.cnpq.br/9302922458814221The prediction of electricity consumption plays a crucial role in the effective management of energy resources. This study investigates electricity consumption forecasting methods applied in the Brazilian context. Four widely recognized forecasting techniques were explored: Exponential Smoothing, ARIMA (Autoregressive Integrated Moving Average), Support Vector Machines (SVM), and Artificial Neural Networks (ANN). The analysis began with the decomposition of the time series, allowing for the identification of trends, seasonality, and random variations in the data. The Holt-Winters Exponential Smoothing and the ARIMA model were used to model the underlying temporal aspects. The Support Vector Machines (SVM) technique was enhanced through parameter optimization, resulting in highly accurate and reliable forecasts. Although it required significant computational efforts, SVM demonstrated remarkable capability in capturing complex relationships. ANN was investigated and emerged as the most effective approach, providing exceptionally precise and robust predictions. This method stood out in capturing complex and sequential patterns, making it the preferred choice for forecasting electricity consumption in Brazil. However, the final choice of the model should consider not only evaluation metrics such as MSE (Mean Squared Error), MAE (Mean Absolute Error), and RMSE (Root Mean-Squared Error) but also adaptation to specific data and computational demands.Item Controle vetorial de velocidade em motor de indução trifásico para aplicações em mobilidade elétrica(2024-03-08) Souza, Guilherme Henrique de Carvalho; Méllo, João Paulo Ramos Agra; http://lattes.cnpq.br/2430890141645755; https://lattes.cnpq.br/6351499728705848The replacement of combustion engines with electric motors is already a reality in Brazil. Hybrid and electric vehicles are gaining more market share every day. This is due to their high efficiency, low cost and, above all, the fact that they do not emit polluting gases into the environment. The study of induction motors for vehicle traction has become a challenge for researchers, who are looking for methods and strategies to maximize their market entry. Speed control of electric motors can be carried out in various ways, such as changing the number of poles, vector control, changing the frequency and supply voltage. Vector control is based on the odq variable transform, which is a good representation of the three-phase induction machine in the vector domain. Through this control, it is possible to decouple the machine's conjugate and magnetic flux, allowing each of them to be explored in isolation. The aim of this work is therefore to develop a closed-loop quadrature vector control system for the electric motor used in the Evolt Racing extension project. This study begins by validating the machine model and the open-loop controls, and then closing the control loop. Finally, the motor is driven via PWM inverter and the braking profiles and methods are compared. The simulations were carried out using PSIM and MATLAB software, and the controllers were tuned using the geometric root locus method. It was possible to validate the machine model, tune the controllers to improve the dynamic response and control the motor speed for the permanent regime.Item ESTUDOS DE PERDAS NOS SEMICONDUTORES E DA DISTORÇÃO HARMÔNICA EM TOPOLOGIAS DE CONVERSORES MULTINÍVEIS(2024-10-03) Silva, João Gonçalves Antunes da; Silva Júnior, Guilherme Penha da; Méllo, João Paulo Ramos Agra; http://lattes.cnpq.br/0439625337029616; http://lattes.cnpq.br/4952843275256497This article presents a study of semiconductor losses and harmonic distortion in multilevel converter topologies. Switching, conduction, and total losses will be analyzed for two-level topologies as well as three- and four-level Neutral-Point Clamped (NPC) topologies at varying frequencies. Additionally, the Total Harmonic Distortion (THD) of the voltage and phase current waveforms will be evaluated. The results include the values of losses and THD for six distinct cases, with variations in standard active and reactive power values, as well as voltage, resistance, and inductance values obtained through simulation. The study also highlights which topology performs better in each case, analyzing scenarios with different voltages and frequencies. The results show that multilevel systems exhibit superior performance at high voltages and elevated frequencies, whereas two-level converters perform better at lower frequencies.Item Desenvolvimento de Estudo de Proteção para Conexão de uma Usina fotovoltaica de 1.194kWp(2023-09-21) Oliveira, Maria Eduarda Araújo de; Alves, Denis Keuton; Ando Júnior, Oswaldo Hideo; https://lattes.cnpq.br/7109075850257262; https://lattes.cnpq.br/8911684468319565The generation of photovoltaic energy presents a different profile from the generation of conventional energy (hydroelectric). This is due to the characteristics inherent to the photovoltaic generation process, such as intermittent generation, in which fluctuations in energy generation occur, adding greater complexity to the protection system. Therefore, this work analyzes current regulations and recommendations for preparing a study on the protection and selectivity of photovoltaic generators. This work used a real case study with a 1MW generator connected to the local utility through a coupling transformer and inverters. The protections and adjustments were selected to assess the reliability of the proposed generator and ensure connection to the distribution network with the minimum quality parameters required by regulations. From the results obtained, it was verified through graphic analysis of the coordination that the method used was effective in the protection and selectivity study, attending to current regulations.Item Estudo de proteção de transformador em uma subestação de 69 kV: parametrização e simulação de aferição do relé de proteção.(2024-03-08) Teixeira, Gustavo Sousa; Silva, Mauren Pomalis Coelho da; http://lattes.cnpq.br/0240476673310276; https://lattes.cnpq.br/8564388656017375The present undergraduate thesis aims to conduct a comprehensive study on transformer protection in a 69 kV substation, focusing on the parametrization and simulation of the protection relay. In the initial phase, a detailed bibliographic review is conducted on the elements of a substation and the most relevant ANSI protection functions, including overcurrent (50/51), undervoltage (27), overvoltage (59), and differential (87) functions. This theoretical foundation provides a deep understanding of the principles and criteria of protection employed in power electrical systems. Subsequently, the necessary calculations are carried out for the sizing of the mentioned protection functions, taking into account the specific characteristics of the transformer and the operating conditions of the substation. The calculations include the determination of current and time settings for the overcurrent functions, as well as the trip values for undervoltage and overvoltage functions. After defining the sized settings, the protection relay is parametrized, configuring it according to the calculated values for each protection function. This process involves programming the relay parameters, ensuring its ability to detect and respond appropriately to abnormal operating conditions. Finally, the protection relay calibration is simulated using a hexaphase test set. This step allows verifying the effectiveness and accuracy of the parametrized settings, ensuring that the relay can operate reliably and selectively in case of fault or overload situations. In summary, this work provides a comprehensive approach to the study and implementation of transformer protection in a 69 kV substation, demonstrating the importance of proper parametrization of protection relays to ensure the safety and reliability of the electrical system.Item Estudo de métodos para o dimensionamento do sistema de armazenamento de energia de um veículo elétrico tipo fórmula(2024-03-05) Alves, Adriany Fabrícia Silva; Araújo, Marcel Ayres de; http://lattes.cnpq.br/0669410110930611; http://lattes.cnpq.br/3796261196279460Faced with the need to reduce carbon dioxide emissions and increasingly reduce the fleet of gasoline vehicles, among other petroleum derivatives, in an attempt to mitigate the damage caused by pollution to the environment, the implementation of Electric Vehicles (EVs). They are a general concept of means of transport that takes advantage of the electric motor as the traction actuator, and one of the main types of EVs are those that use batteries as an energy storage system, also known as BEVs (Battery Electric Vehicles). BEVs are considered a solution that has the potential to mitigate greenhouse gas emissions and reduce the use of oil in the transport sector, avoiding energy crises. EVs present a technological evolution of transforming electrical energy into movement, which consequently has increased interest in electric propulsion for automobiles in recent years. They are designed to be competitive in terms of cost-benefit with conventional vehicles in the coming years. Given its importance, this work addresses a significant context of growth in the battery electric vehicle fleet in Brazil, from its technological characteristics, challenges, potential problems and benefits, through its energy transmission system, and its operating dynamics. After the theoretical foundations and all bibliographical references researched, the main objective is to study the sizing of this storage system aimed at BEVs applied to a formula-type EV. As a result, this study developed a detailed methodology for sizing formula-type vehicle power, force and energy, based on an in-depth analysis of the electric vehicle routing problem, exploring its different variants and possible solution approaches. Next, proceed to sizing the battery pack using a series-parallel configuration used to supply the ordinary power. Finally, the battery selection was carried out through MCDA statistical analysis using the AHP-Gaussian and AHP-Gaussian with Pearson Correlation method, resulting in the choice of the SLPBA096235 cell as the discovered technology, which declared nominal values in agreement and compatible with the main specificities related to formula-type EVs for the scaled system.Item Desenvolvimento de um protótipo de um software para um sistema não cabeado de captação de eletrocardiograma para experimentação em modelo animal(2022-10-06) Caetano, Maria Luiza Guerra; Nogueira, Romildo de AlbuquerqueUsually, cardiac activity variability research has as its methodology a study of cardiac autonomic control. In animal experiments, electrophysiological signals are obtained using chemical (drug) or mechanical (container) containment methods, which produce artifacts in the signal of interest. A solution to avoid the inconvenience produced by these procedures is the use of wireless capture systems attached to the vest. Despite the existence of equipment with this technology, the reality of research laboratories comes up against the high cost of acquiring this equipment and the relative difficulty of the size of the vests, which are produced for dogs and cats, given that they are aimed at the medical clinic. small animal veterinarian. This manuscript presents the results obtained in the development of a software prototype for a graphical interface of an unwired system for recording the electrocardiogram of Wistar rats. To analyze these results, the data obtained were compared with those captured through a wired system using commercial software. For this, the detrended fluctuation analysis (DFA) of the referred data was used, where no statistically significant differences were observed between the mean valuesobtained between the systems. Taking into account the initial results, it indicates that it is viable for improvement and future use in the experimental routine with Wistar rats, seeking to improve the quality of the data and better comfort for the experimental model.Item Desenvolvimento de um procedimento para testes e análises de proteção em IED SEL-751A com auxílio da maleta de testes CE-6710 em ambiente industrial(2024-06-07) Lima Júnior, Valdomiro Ferreira de; Araújo, Marcel Ayres deTechnological development has played a crucial role in the transformation of the Electrical Power System (SEP) and, consequently, in the industry, improving protection devices to ensure greater continuity and reliability for the supply of electrical energy to consumers. Intelligent Electronic Devices (IEDs) stand out as fundamental pieces in the protection of electrical systems from energy projections, as well as in substations and industrial plant installations, promoting automation and real-time monitoring, and offering functions from protection shifting to operational integrity. Considering the increasing complexity of electrical systems in industry, the implementation of robust procedures becomes necessary to maintain their integrity and the continuity of their processes, in addition to contributing to operational efficiency. Thus, the objective of this study is to contribute to the development of a protection testing procedure and parameter settings for IEDs used in the scope of applications for an industrial plant based on the IED SEL-751A, thus enabling an increase in reliability of the electrical systems, investigative analysis of possible operational problems of the device, and guarantee of operational safety, directly reflecting on productivity and industrial performance. To this end, the work proposes a gradual methodology to carry out tests on the IED SEL-751A, establishing its steps such as communication with the device, configuration using the CE-6710 case and parameter adjustments through the Conprove Test Center software in order to guarantee efficiency. and test security. This approach includes the 50/51 overcurrent test, with time and pickup analysis in relation to the protection parameters applied to the relay. Furthermore, a practical case study that occurred in the industry is presented, in which the procedure is applied to investigate an incident that occurred with a Siemens SIPROTEC relay, model 7SJ62, demonstrating the effectiveness and applicability of the principles outlined in this procedure not only for the SEL- 751A, but also for other devices. The test results are then detailed, including the protection curves and the data obtained for the fault simulations. These values are compared with the real and nominal values of each quantity demonstrated, determining whether the relay passes or fails for each fault scenario. missing, and certifying the functionality of the device.Item Impactos, oportunidades e perspectivas para a implementação da eletrificação dos meios de transporte no Brasil(2024-03-07) Siqueira, Breno Filipe Andrade Lima de; Neto, Fernando Gonçalves de Almeida; http://lattes.cnpq.br/0473869396914603; https://lattes.cnpq.br/1256466512019055Technological advancements associated with mobility, growing concerns regarding energy resource scarcity, studies and perspectives on global climate change, and discussions related to environmental preservation have underscored the need for modernizing transportation methods that align with less environmentally aggressive actions, paving the way for electromobility technologies. In this context, this paper addresses the importance of electric mobility as a response to the challenges of climate change and the need to reduce greenhouse gas emissions. Additionally, it discusses the impacts, opportunities, and prospects for implementing the electrification of transportation in Brazil, from the perspective of the impacts of guiding public policies for its implementation, including tax incentives, subsidies, regulations, and standards. Methodologically, the study was based on a qualitative research approach, conducted through consulting academic studies, technical reports, statistical data, public policies, and governmental documents related to the electrification of transportation. The results reveal that Brazil is moving at a slower pace in regulating electric mobility compared to countries such as China, the United States, and countries in the European Union, but it remains a niche with great potential for expansion and consolidation of electromobility- associated technologies. Based on the study conducted, this paper highlights practical implications and possible future directions for the adoption and promotion of electric mobility, considering the experiences of countries that are more advanced in adopting electric mobility as an alternative to combustion vehicles.Item Análise e controle de distorções harmônicas utilizando modelagem com filtros passivos(2024-03-11) Santos, Fernanda Maria Vanderlei; Alves, Denis Keuton; http://lattes.cnpq.br/7109075850257262; https://lattes.cnpq.br/1585511995867132With the evolution of power electronics for the control and optimization of industrial flows and processes, challenges related to the quality of electrical energy have become more prominent, especially harmonic distortion. Therefore, understanding the main causes, impacts, and fundamental mitigation strategies becomes crucial to ensure that an electrical system operates with maximum quality and efficiency. In industrial environments, where frequency inverters are used for motor control and nonlinear rectifiers are employed to convert alternating current into direct current to power a variety of electronic devices, the presence of distorted content in current and voltage signals has become increasingly common. These distortions can result in problems such as overheating of transformers and cables, failures in sensitive electronic equipment, among other disturbances. Thus, this work proposes a theoretical and simulated study on harmonic distortions present in a load with a three- phase rectifier, with a focus on the application of a passive shunt filter to attenuate the harmonic content of the system. The use of passive filters offers a significant cost-benefit ratio, as the investment required for their implementation is relatively low compared to other approaches. Additionally, these filters have the ability to select and eliminate specific harmonics, which were previously calculated in the design phase. With the completion of this study, the aim is to achieve a system with controlled harmonic indices, thus validating the effectiveness of the methodology under analysis.