Desenvolvimento de técnica de detecção otimizada de sinais do arco elétrico para monitoramento de disjuntores de alta tensão.

Abstract

In this work the development of a technique to detect electric arc signals for the monitoring of high voltage circuit breakers is presented, with effective reduction of the sampling efforts of the high frequency signals. For this purpose, the envelope detection technique was applied and evaluated. In addition, with the objective of presenting the development of the technique itself, simulations of the detector circuit were carried out in the time and frequency domain. In order to evaluate if the proposed technique is capable of estimating the evaluative parameters of circuit breakers, transient electromagnetic emissions from the process of opening a 15 kV circuit breaker were acquired at the UFCG High Voltage Laboratory. The sensitivity analysis of the extraction of the parameters of electric arc duration and energy of the signal, from the envelope of the arc signal, was made. For this, envelopes of the measured arc signals were obtained by simulation. The developed envelope detection technique showed accuracy in the calculation of the electric arc duration parameter, with errors lower than 2% in relation to the original signal. The energy parameter of the arc signal could be detected with the application of the technique; however, it was observed that a calibration of the system must be made to achieve the best performance. In addition, the project and evaluation procedures of the envelope detector circuit were presented, focused on the application of the arc signals analyzed in this work. The results obtained in this work evidenced the potential of the envelope detection technique to reduce the sampling efforts of the arc signals. Therefore, it is proven that envelope detector circuitry can be applied as input to a circuit-breaker monitoring device in service, requiring a less complex and more affordable signal acquisition, transmission and processing system.