Research On Electric Field Distribution Of Catenary Polluted Insulators Under Salt Fog

The coastal areas of China have high humidity and high salt fog concentration,and are prone to pollution flashes and rain flashes,which have a great impact on the normal operation of the railway.The presence of salt mist will cause wet pollution on the surface of the insulator,increase its surface conductivity,and the special structure of the insulator leads to uneven electric field distribution.These factors increase the distortion rate of the electric field of the insulator,making the insulator more prone to flashover.Therefore,according to different salt fog conditions and various weather conditions,it is of great significance to analyze the electric field characteristics of the composite insulator of the catenary under these conditions,and it has great reference value for the study of the flashover characteristics of insulators in coastal areas.This paper selects the FQBG-25 type insulators commonly used on electrified railways as research objects,establishes an insulator model in the finite element simulation software,and analyzes the electric field distribution of insulators based on electrostatic field theory analysis.According to different salt fog conditions and weather conditions,simulation models of clean insulators,insulators under four salt fog conditions and insulators under four weather conditions were established respectively,and the surface electric field of insulators under various conditions was analyzed.Build an insulator model in COMSOL Multiphysics software,set up four salt sprays with different conductivity,and compare and analyze the influence of these four salt spray conditions on the potential and electric field of the insulator.Analyze the effect of salt spray conductivity on flashover voltage under different salt density(SDD)through experiments,and introduce the concept of additional salt density(ASDD),the effect of salt spray conductivity is completely equivalent to the additional salt density,for more accuracy The effect of adding salt density on the flashover voltage is introduced,and the salt density correction coefficient K is introduced to modify the classic flashover voltage formula.Compare the electric field distribution of the insulator under salt fog conditions with the insulator under three weather conditions of less rain,no rain,light rain and heavy rain.Dirty insulators are analyzed under four weather conditions: foggy,little rain,no rain,light rain,and heavy rain.