DEELT - Artigos publicados em periódicos
URI permanente para esta coleçãohttp://www.hml.repositorio.ufop.br/handle/123456789/5267
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Item A new admittance approach applicable to the coordination between the loss-of-excitation protection and the underexcitation limiter.(2020) Baracho, Francisco Ricardo Abrantes Couy; Coelho, Aurélio Luiz Magalhães; Pereira Filho, Clever Sebastião; Damião, Laerty João dos Santos; Zvietcovich, Wilingthon GuerraThe performance of salient-pole synchronous generators protection is of great importance for the stability of power systems, as they are present in large hydropower plants, subject to various abnormal operating conditions such as threephase or two-phase faults, electromechanical disturbances and lossof-excitation. In this context, this work proposes a testing philosophy of salient-pole synchronous generators, in order to define more accurately the setting of the protections and controls of this asset. Thus, in the developed methodology, the admittance plan (G-B) proves applicable to analyze the coordination between the loss-ofexcitation protection and the underexcitation limiter, as an alternative to the power (P-Q) and impedance (R-X) planes, normally employed in literature. In modeling the problem, real data for both the hydrogenerators and the electrical network are used. The simulations were performed in a hardware-in-the loop scheme integrated by a Real Time Digital Simulator and a physical relay. Thus, analyzes are made for situations of stable power swing and partial and total loss-of-excitation. The results are useful to prove, through the monitoring of relevant variables of the hydrogenerators, the feasibility and accuracy of the G-B plane in the coordination between the protection and the control of the synchronous machineItem Técnica de localização de faltas em linhas de transmissão empregando o método dos mínimos quadrados.(2019) Barbosa, Gustavo Vinícius Duarte; Pereira Filho, Clever Sebastião; Baracho, Francisco Ricardo Abrantes Couy; Santos, José Ronaldo Tavares; Damião, Laerty João dos SantosA investigação de diferentes tipos de faltas em linhas de transmissão é uma tarefa complexa e de extrema importância para o Sistema Elétrico de Potência (SEP). A modelagem da linha de transmissão deve ser estabelecida da forma mais rigorosa possível, visando à precisão das distâncias de faltas simuladas a partir dos modelos levantados. Neste trabalho será modelada uma linha de transmissão em circuito simples usando o programa de cálculo de transitórios eletromagnéticos ATPDraw® e, posteriormente, o algoritmo de localização de falta baseado no emprego do método dos mínimos quadrados será implementado no MATLAB®. O desempenho do método será discutido em termos de precisão e robustez dos resultados.Item A theoretical and practical approach for underexcitation protection and control studies of hydrogenerators in a real-time environment.(2018) Baracho, Francisco Ricardo Abrantes Couy; Pereira Filho, Clever Sebastião; Coelho, Aurélio Luiz Magalhães; Silveira, Paulo Márcio da–The installation and settings of protection devices and excitation control systems require experience since a failure can cause damage to the synchronous generator and negative impact on the power grid. A test bed implemented in a real-time digital simulator is presented in this paper as an alternative for the training and learning process that involves the knowledge of an effective coordination between such protection and control systems of synchronous generators. A complete generation system is implemented in a real-time digital simulator, including an excitation system model with its limiters. These limiters are coordinated with the protection functions implemented in a physical relay. The contributions of this work are: the demonstration of the importance of this type of study (i.e., real time simulations results through hardware-in-the-loop tests); the consolidation of the impedance (R-X) and admittance (G-B) planes as the more appropriate ones to analyze the coordination between the ANSI 40 function and the underexcitation limiter; and the presentation of a study focused on hydrogenerators (including novel settings for the ANSI 40 protection).