Partial Discharges Characteristics of Harmful Conducting Particles Around Spacer Under AC Voltage in Atmospheric Air

Harmful metallic particles inside gas insulated switchgears (GISs), which are the most problematic among various defects in a GIS, is significant to the reliable operation of such electric equipment in power transmission network. This paper investigates, on an experimental basis, the partial discharge (PD) characteristics initiated from particles under ac voltage in atmospheric air with those placed freely on the lower electrode´s surface of GIS model, having adhered to the insulated spacer´s surface, and fixed on the upper electrode´s surface, respectively. PD and breakdown characteristics in terms of the particle size (length and radius) and the location between the spacer and the particle have been studied in detail. All results are compared with each other to clarify the influence of the particle geometry size and location on PD characteristics. The amount of PD pulses in unit time, which shows the severe extent in PD, has been also investigated. The influence mechanism of the particle location on PD characteristics is discussed in this paper.