Study of GIS Partial Discharge On-line Monitoring Using UHF Method

According to the structure characteristic and operation performance of the field gas insulation switchgear (GIS), an external ultra high frequency (UHF) sensor, a novel microstrip patch antenna (MPA), is designed to detect UHF partial discharge (PD) signals for the field GIS. The microstrip patch antenna, which receives the UHF electromagnetic wave leaked from the GIS basin insulator, is just mounted on the GIS basin insulator, and has some effect to suppress the surrounding space electromagnetic interference. The analysis and on-site measurements manifest that the MPA working frequency bandwidth is 340MHz to 440MHz, which voltage standing-wave ratio (VSWR) is less than 2, the center frequency is 390MHz, the relative bandwidth is 25.6% up to the wide bandwidth range, and its gain of the maximum radiation and reception directivity is covered 5.38dBi. The laboratory GIS simulation device and field GIS measurements data indicate that the novel UHF antenna sensor has perfect property, higher sensitivity. It is suited for GIS field partial discharge UHF on line detection and diagnosis.