Sistema de monitoramento e metodologia de estimativa dos tempos de operação do disjuntor. / Monitoring system and methodology to estimation of circuit breaker operation times.

AUTOR(ES)
DATA DE PUBLICAÇÃO

2005

RESUMO

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.

ASSUNTO(S)

monitoramento de disjuntor wavelet transform and fourier transform signal processing transformada fourier e wavelet processamento de sinais circuit breaker monitoring

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