AC Flashover: An Analysis with Influence of the Pollution, Potential and Electric Field Distribution on High Voltage Insulator

This paper presents a work devoted to the impact study of the pollution severity on the energy level dissipated on high voltage insulator. Pollution of high voltage insulators is a factor of prime importance in the quality and reliability of power transmission. It causes the circumvention of high voltage insulators. However, when it is wet, it causes the dissolution of salts and the formation of an electrolyte layer on the surface of insulators, thus reducing dielectric strength. Pollution generally poses few problems. However, when it is humid, it causes the dissolution of salts and the formation of an electrolytic layer on the insulator surfaces; as a result, it reduces their dielectric rigidity.

The aim of this paper is the experimental study of the flashover process and the distributions of the potential and the electric field pollution carried out under 50 Hz applied voltage on a circular model simulating the 1512 L outdoor insulator largely used by the Algerian company of electricity and gas (SONELGAZ). This circular model is under different surface conductivity and different level of uniform discontinues pollution.

The computer simulations are carried out by using the COMSOL Multiphysics 3.5 software. This program uses the finite element method to solve the partial differential equations that describe the field. Original experimental results made in the laboratory are presented and compared with a real insulator, and simulations presented in this paper are originals.