Analysis of transient electric field for epoxy spacer under lightning impulse voltage

A transient electric field takes place in gas-insulated switch-gears (GIS) while lightning impulse voltage is imposed on it. Taking permittivity, conductivity, and polarization loss into consideration, the differential equations of transient field are deduced, where the response caused by lightning impulse voltage is expressed by Duhamel integration. The equivalent conductivity contributed by polarization loss of epoxy spacer is obtained from the experiment. The potential distribution curves of epoxy spacer in GIS are given at representative time, and the electric intensity distribution curves on the spacer surface with respect to time are illustrated. The maximum of intensity on the spacer surface is also calculated, which is compared with the one in the static field. Some distinguishing features of the transient field in GIS are also discussed