Experimental investigation of particle-initiated surface flashover in air and N2 in uniform gap under 60 Hz voltage

The authors report an experimental investigation of the prebreakdown current and flashover characteristics of discharges initiated by a wire particle attached to an epoxy resin spacer in air of atmospheric pressure and N₂ at a pressure ranging from 50 to 500 kPa under a 60-Hz voltage. It is shown that the particle-initiated surface flashover is strongly influenced by the prebreakdown process, which is quite different from that in the absence of a spacer. The presence of the spacer not only changes the discharge form, but also modifies the polarity effect. The flashover voltage is dependent on factors such as particle size, its location on the spacer, the surface charging process, and gas pressure. The flashover voltage is strongly influenced by the particle location on the spacer. The surface contamination of the spacer plays a crucial rule at higher pressure