Partial Discharge Characteristics of Protrusion Defect in SF6 under Stepped AC Voltage

This paper investigates the partial discharge characteristics of protrusion defect in SF6 gas insulation under stepped alternating current voltage. Two kinds of partial discharge detection techniques are used, e.g. phase-resolved partial discharge pattern and current pulse waveform analysis. The partial discharge patterns and current pulse waveform are obtained by using a commercial partial discharge measurement system and oscilloscope, respectively. With the applied voltage raised in a regular step, the patterns of partial discharges are recorded. From the results of phase-resolved partial discharge patterns and some deduced histograms, statistical operators like as skewness and kurtosis are calculated, and used to investigate the partial discharge characteristics. After that, the…