Influence of charges on spacer surface flashover in air and SF/sub 6/

Cylindrical spacers of Polymethyl methacrylate, polytetra fluoroethylene, Epoxy and Nylon with a conducting particle on the surface have been subjected to lightning impulse voltages (1.2/50 /spl mu/sec) under uniform electric field in air and under non-uniform electric field in SF/sub 6/. The effect of lightning impulse voltage polarity, gas pressure, permittivity, charged source position on surface flashover of spacers and v-t characteristics are discussed Surface morphology of spacer after flashover events in air and SF/sub 6/ are presented.