Analysis of Electric Field Distribution for Polymeric Insulators under Ice Conditions using Finite Element Method

The use of polymeric insulators in new lines and also updated power transmission lines is still growing. Polymeric insulators are exposed to various electrical, mechanical and environmental stresses. In many areas with cold weather, high voltage transmission lines and substations are vulnerable to freeze. The most important problems of these polymeric insulators, such as erosion and aging of polymeric materials, corona phenomena on insulator surface and flashover are related to the nonuniform potential distribution along the insulators. In this paper, electric field and voltage distribution of 230 kV polymeric insulator has been evaluated with and without corona ring in the presence of an ice layer on it. Electric field analysis software package, COMSOL Multiphysics4.2, based on the finite element method, has been employed for the calculations. Simulation results have shown a dramatic decrease in the intensity of the electric field in polymeric insulators in the presence of corona ring. Also the presence of air gap in the ice layer has a great influence on the potential distribution along the polymeric insulators and causes to increase intensity of the electric field on polymeric insulators surface.