Analysis of Ultrasonic Signal Propagation of Partial Discharge in Gas Insulated Switchgear

Partial discharge (PD) is a significant element contributing to insulation degradation in gas-insulated switchgear (GIS). The ultrasonic detection method is a non-destructive approach commonly employed for PD detection in power equipment, as it is immune to electromagnetic interference. Hence, the paper simulates and analyses the propagation of ultrasonic signals in the interior by building a simplified model of GIS three-dimensional finite element simulation. To analyze the propagation pattern and amplitude change of the partial discharge ultrasonic signal sound pressure in space, the propagation path of the ultrasonic wave and the attenuation of the sound wave in the case of a single PD source. Simulation results show that ultrasonic waves propagate in the form of spherical waves through transient analysis, and ultrasonic waves propagate in the GIS gas chamber with multipath effect and non-line-of-sight effect, the ultrasonic signals attenuate significantly with distance and medium, and the central conductor seriously impedes the propagation of ultrasonic waves. The results of the study have positive significance for the optimal arrangement of ultrasonic sensors, and provide a basis for ultrasonic PD positioning.