UHF Sensor for Partial Discharge Detection Based on Coplanar Waveguide Feeding

The ultrahigh-frequency (UHF) method has found wide application in the field of partial discharge (PD) detection in gas-insulated switchgear (GIS). UHF sensor is an essential component and whose performance has a significant influence on the effectiveness of PD detection. In this article, a microstrip antenna is designed as a potential UHF sensor for PD detection by adopting coplanar waveguide feeding. The geometric model of the antenna is first established based on electromagnetic theory. The effect of key dimension parameters on the performance of the antenna is explored, and thereafter, these parameters are optimized considering the demands of PD detection. A trident-shaped feeding strip is loaded to further improve the antenna performance. The obtained results show that the working band of the proposed UHF antenna is 500–1120 MHz, while the radiation characteristics are approximately omnidirectional, with a peak gain of 4.6 dB and an average gain of 3.4 dB. PD experiments are carried out for two typical artificial defects of corona and internal discharges to verify the effectiveness of the designed sensor. It is indicated that the antenna can effectively detect PD signals, showing a potential application in PD detection of GIS.