Analytical Model for Investigating Linear and Nonlinear Behavior of Thin Semi-Conductive Layers on Insulator Surface

Abstract

This article is aimed at the investigation of the electrical potential and field distributions along an insulating system covered/coated with a thin semi-conductive layer usually found on outdoor insulator surface or used on the end-windings of rotating machines and high voltage (HV) terminations. For that purpose, a model is proposed to compute analytically the electrical potential and field distributions along the insulator surface. The peculiarity of this model is that it considers both conduction and displacement currents within the thin semi-conductive layer. The results of this new model are compared with those reported in the literature and those obtained by numerical methods such as the collocation spectral method (CSM), finite difference method (FDM), and finite element method (FEM). The influence of the thin semi-conductive layer parameters is discussed in linear and nonlinear cases to show the advantage of the use of a semi-conductive thin layer as a coating stress grading material in HV equipment.