Simulation of VHF-UHF Radiation and Leakage Characteristics of GIS Partial Discharge with Different Insulator Types

The ultra-high frequency (UHF) and very high frequency (VHF) electromagnetic waves radiating from internal discharges within gas insulated switchgear (GIS) can escape into the surrounding space through non-metallic components. This phenomenon presents an opportunity for detecting partial discharge (PD) signals using high-frequency sensors and locating the sources of discharges. The GIS basin insulator structure primarily comprises metal shield and open types. In the event of internal insulation discharge, non-metallic components such as casting holes or flange gaps in metal closed insulators can release electromagnetic waves into the external space. Similarly, open devices can directly emit electromagnetic signals to the exterior through the basin insulator. This paper establishes simulation models for two typical GIS structures and investigates the leakage characteristics of electromagnetic waves in the VHF and UHF bands. Studies have shown that open insulators exhibit greater signal leakage ability in both the VHF and UHF bands. The high-pass characteristic of the antenna results in significantly lower leakage parameters in the VHF range compared to the UHF range. This conclusion offers theoretical insights for guiding the selection of frequency bands in subsequent partial discharge sensor research.