Effect of leakage current on the residual resistance of an ice surface

In static and dynamic arc models to predict AC and DC critical flashover voltages of an ice-covered insulator, residual resistance for a given value of the length of the arc and feeding water conductivity is assumed to be constant. For this hypothesis, however, the thermal effects on an ice surface are not taken into consideration. In this paper an accurate model to figure out joule heating effect over an ice-covered insulator is presented where (a) water film layers are assumed to have different conductivities, and (b) Joule heating due to leakage current and liquid falling off the water film due to gravity are considered with the first effect increasing water film thickness and the second one decreasing it.