Investigation of electrical insulation diagnosis of solid insulators in GIS by partial discharge current pulse waveform analysis (PD-CPWA)

The authors propose a novel approach based on partial discharge (PD) current pulse waveform analysis (PD-CPWA) in order to assess insulation degradation of solid insulators with different kinds of defects. The CPWA technique focuses on the time transition of individual PD waveform parameters like rise time, fall time and di/dt in the time-resolved waveform of a single PD current pulse. They measured PD characteristics by PD-CPWA using insulation defect model spacer. Experimental results revealed that number of positive PD increased drastically just before BD, with some discrete rest time before BD. The last PD leading to BD was successfully identified.