Projeto e implementação de um circuito para detecção de sinais de descargas parciais.

Abstract

The electric energy regulatory agencies and the consumer requirements propitiate that the electric energy companies increase its confiability. Thus, the electric equipments monitoring become essential in this context. The partial discharge measurement techniques have been used in electric equipment ageing monitoring. Partial discharges are electric discharges that only partially bridge the insulation between conductors. The partial discharges presence can identify prejudicial situations to the equipment insulation submitted to high voltages. To obtain an adequate diagnostic about the prejudicial effects of the partial discharge signals, it must quantify the discharges and also measure its magnitude, frequency, repetition rates, among others. An ideal measurement of the essential parameters present in the partial discharge signals is obtained when the partial discharge detector has capacity of not distort and attenuate these parameters. As the partial discharge signals are high frequency pulses, in this work, a large band detector is projected and implemented. It is composed for a 50 Q impedance and an 50 MHz passband amplificator with a 2,75 MHz cutoff frequency. The partial discharge generation, detection and measurement tests are accomplished. The obtained results using the commercial and the developed detector are compared.