Calculation of current density along insulator surface using field and circuit theory approaches

The paper presents two different methods to compute the current density along contaminated and wet silicone rubber insulator surface. The first method, based on field theory approach, uses the commercial software FEMLAB® to compute the current density. The conductivity of the contamination layer used in the calculations was extracted from the measured equivalent salt deposit density (ESDD) separately for different regions of the insulator surfaces. The second method is based on the circuit theory approach, and, the insulator surface was divided into different sections for resistance calculations to account for different contamination levels. Rankings based on the calculated current densities based on segmentation of the insulator surface for ESDD measurements match with those extracted from measured leakage currents.