Optical Detection of Corona Discharge Based on SiPM at DC Voltage

Partial discharge (PD) is a significant technique to detect and estimate the insulation fault in the gas insulated switchgear (GIS). However, the PD signal acquired on-site is always coupled with noise or interference. In this paper, a PD optical measuring technique based on the silicon photomultiplier (SiPM) was applied to measure corona discharge under DC voltage. The SiPM structure and optical signal processing circuit were first introduced. The corona discharge at the different PD inception voltages was measured. The PD optical signal and the electrical signal were compared in time and frequency domain respectively. Experiments show that the SiPM sensor can effectively detect the PD pulses as the PD measurement based on the electrical signal. PD optical signal is an impulse signal with a higher amplitude and shorter duration which is beneficial to filter the noise.