Partial Discharge Characteristics of Post Insulators for 10 kV Switchgear at Different Humidities

Abstract-The moist air inside the HV switchgear can cause partial discharge (PD) on the surface of the post insulator, damaging the insulation performance. This paper explores the impact of humidity on the PD of post-insulators, analyzing the PD spectra and related parameters under varying humidity. The results show that when relative humidity is 40 %, the average discharge increases with voltage, yet the PD spectra remain similar under different voltages. When relative humidity reaches 60 % or 80 %, the spectra display diverse PD sources related to the distribution and movement of drops on the post insulator’s surface at different voltages.