The optimal circumferential angle position of UHF sensor for partial discharge detection in GIS

Ultra-high-frequency (UHF) technique for detecting partial discharge (PD) phenomenon is a useful method to avoid insulation accidents in gas insulated switchgear (GIS). However, the circumferential angle position of UHF Sensor in GIS has a great effect on the PD detection, which has not been investigated sufficiently. To deeply investigate the propagation characteristics of UHF signal and improve the application of the UHF technique, the influence of circumferential angle position of UHF Sensor in GIS is studied by performing several experiment tests in this paper. Applying two-arm equiangular spiral antenna as PD sensor, which is designed and optimized previously, the experimental platform is built based on a actual 252 kV GIS tank. Then, a protrusion defect is set on three circumferential angle positions respectively to achieve different relative position of the sensor and the defect, and the UHF signal received by the sensor in each case are analyzed statistically. The results indicate that different relative position of the sensor and the defect does have obvious influence to the received signal. Because the transmission rate of the UHF signal is the highest when the circumferential angle between the sensor and defect is 0°, this position is considered to be the optimal circumferential angle position of UHF Sensor to detect PD in GIS. This paper gives some referential suggestion for the rational application of UHF method in PD detection.