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Doctoral Thesis
DOI
https://doi.org/10.11606/T.3.2005.tde-06052005-143916
Document
Author
Full name
Milthon Serna Silva
E-mail
Institute/School/College
Knowledge Area
Date of Defense
Published
São Paulo, 2005
Supervisor
Committee
Jardini, Jose Antonio (President)
Coury, Denis Vinicius
Magrini, Luiz Carlos
Pereira, Sergio Luiz
Senger, Eduardo Cesar
Title in Portuguese
Sistema de monitoramento e metodologia de estimativa dos tempos de operação do disjuntor.
Keywords in Portuguese
monitoramento de disjuntor
processamento de sinais
transformada Fourier e Wavelet
Abstract in Portuguese
O presente trabalho visa o desenvolvimento de um sistema de monitoramento de disjuntor voltado a coletar informações para manutenção preditiva. São analisadas as características das variáveis que são monitoradas através de sensores ligados ao disjuntor, sua aquisição e o tratamento das informações. Um protótipo foi desenvolvido e instalado na subestação de Sumaré 440kV de ETEO (Empresa de Transmissão de Energia do Oeste Paulista). Um assunto importante para a manutenção é a avaliação dos tempos envolvidos na movimentação dos contatos principais do disjuntor principalmente na operação de abertura do curto circuito. Para tal é proposto um sistema não intrusivo que analise a oscilografia das tensões e correntes no disjuntor sincronizado com as correntes no circuito de disparo deste equipamento. A Transformada de Fourier aplicada no sinal de corrente/tensão sem perturbação permite determinar o valor do componente fundamental desse sinal. Com esse valor pode-se gerar uma senóide que superposta com o sinal coletado pelo oscilógrafo permite visualizar a alteração. A Transformada Wavelet é realizada através de filtros decompondo-se o sinal de corrente ou tensão em Análise Multiresolução, em diferentes estágios obtendo-se em cada, uma versão chamada aproximação (baixas freqüências) e uma de detalhes (altas freqüências), sendo assim, os distúrbios podem ser detectados e localizados no tempo em função do seu conteúdo de freqüência.
Title in English
Monitoring system and methodology to estimation of circuit breaker operation times.
Keywords in English
circuit breaker monitoring
signal processing
Wavelet transform and Fourier transform
Abstract in English
The present work addresses the development of a circuit breaker monitoring system so as to collect information for predictive maintenance. The characteristics of the variables that are monitored through certain sensors linked to the circuit breaker, its acquisition and the treatment of the information, are analyzed. A prototype was developed and installed at the 440kV Sumaré substation of ETEO (Empresa de Transmissão de Energia do Oeste Paulista) a Brazilian Transmission Company. An important aspect for the maintenance is the evaluation of the times involved in the movement of the circuit breaker main contacts, mainly at the opening operation for example during a short circuit. On this respect, a non-intrusive system that analyzes the oscillography of both voltages and currents in the circuit breaker synchronized with the currents in the tripping circuit of this equipment is proposed. The Fourier Transform applied to the current or voltage signal with no disturbance allows to determine the value of the fundamental component of this signal. With that value, it can be generated a pure sine wave which when overlapped to the signal collected by the oscillograph allows to visualize alterations. The Wavelet Transform is realized through filters and decomposing the current or voltage signal through the Multiresolution Analysis at different levels, in this way, obtaining in each level, a version called approximation (low frequencies) and another with details (high frequencies), thus, the disturbances can be detected and located in the time and as a function of its frequency content.
 
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MILTHON.SERNA.pdf (1.83 Mbytes)
Publishing Date
2005-05-17
 
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