Electrical Field and Potential Distribution Simulation of 220 kV Porcelain String Insulator Using COMSOL Multiphysics

Abstract

Fidelity of the network and its equipment is imperative for the performance of electrical power system. Electrical energy from generating station is transmitted through high-voltage lines to the load centres. Insulators are used to both support as well as separate the conductors at high voltage. They are designed to withstand not only just typical voltages but also over-voltages by the virtue of switching events or lightning effect besides environmental stresses like snow, rain, pollution. Insulators employed to transmit/distribute the electric power are usually made up of ceramic/glass/polymer material. When the local electric field on the surface of high-voltage insulator is greater than the ambient air’s ionization value it leads to the discharge activity. Environmental conditions like rain, fog, pollution along with the high voltage affect the electric field. Electric field grading techniques can be used to better design the insulators provided the electric field on the surface of the insulator is known. Surface flashover may occur on the ceramic insulators when the applied electric field is high enough. Consequently, grading devices are required to keep the electric field under acceptable levels. Objective of the aforementioned research is to study the electric field and potential distribution (EFPD) along the ceramic insulators. Firstly, under clean/dry conditions and then under various levels of Sodium Chloride (NaCl) pollution using finite element method. The computer simulations are realized using commercially available CATIA and COMSOL multiphysics software packages. The simulation results obtained are presented and analysed.