Partial Discharge Characteristics of Typical Defect Models by Optical-UHF Combined Detection

Currently, conventional electrical methods such as the ultra-high frequency (UHF) method are widely used for detecting partial discharge (PD) in gas-insulated switchgear (GIS). However, due to on-site interference and system noise, these methods are prone to missed detections and false alarms. To improve the accuracy of partial discharge detection and further investigate the discharge characteristics of different defects in GIS, a combined optical-electrical sensing technology based on ultrahigh frequency (UHF) antennas and silicon photomultipliers (SiPM) is proposed. The test results of the optical-electrical combined sensor for typical defect discharge signals indicate that both the optical signal and the UHF signal of the sensor maintain a linear relationship with the discharge magnitude. The opticalelectrical combined sensing exhibits different detection efficiencies for corona discharge, surface discharge, floating discharge, and air gap discharge. Additionally, the discharge intervals of partial discharges vary with different defect types. The optical-electrical combined detection technology provides a novel and reliable solution for partial discharge detection in GIS.