Rejection of composite noise in PD measurement for power plant condition monitoring

Partial discharge (PD) activity is both a symptom of degradation in the insulation system of power plant, irrespective of the causative stresses, and a stress mechanism which causes degradation. It can therefore be readily appreciated why the detection, location and interpretation of partial discharge activity is an attractive technique to the diagnostic engineer [1]. However, a major bottleneck encountered in PD measurement is the ingress of noise. Noise may change the waveform of the PD pulse or even drown it out. The interpretation of PD signal and corresponding pattern recognition would be valueless if ‘clean’ pulses could not been acquired. It is therefore crucial that techniques for noise suppression are employed in PD measurement.