Study of Voltage Distribution and Radial Electric Field under Different Pollution Conditions of 500kV MOA

Abstract

The surface of the porcelain sleeve will be polluted by local environmental pollution and weather factors such as frost, rain and snow, because of the 500kV MOA is generally arranged outdoors. The surface flashover problem of the porcelain sleeve surface caused by contamination is similar to that of the insulator surface. It is a resistor column with three sections connected in series inside the arrester. The influence of surface contamination on the voltage distribution of the internal resistor and the radial electric field between the resistor and the porcelain sleeve remains to be studied. In this paper, ANSYS is used to establish a two-dimensional axisymmetric simulation model for the surface contamination of 500kV zinc oxide arrester. The electric field distribution of the surface of the arrester is cleaned, evenly polluted and the local drying zone appears. The results show that the uniform contamination is inside the arrester. The electric field has little influence, and the local drying zone will form a locally excessively high radial electric field between the resistor and the porcelain sleeve. Under the reference voltage, the radial electric field exceeds the corona starting field and causes corona discharge, and the acceleration resistor Deterioration of the sheet and the dielectric; the voltage of the resistor piece near the local drying zone is increased to a certain extent, which also accelerates the aging of the resistor chip and jeopardizes the safe and stable operation of the arrester.