Study On Contamination Characteristics And Electric Field Distribution Of Roof Insulators On High Speed Train

The EMU uses the traction power supply system as the power source,and the roof insulator serves as a high-voltage insulation component for isolation and support.It is a key to ensure the safety of the traction power supply system and the stable operation of the EMU.Because Beijing-Shanghai high-speed rail passes through Shandong,Hebei and other industrially polluted areas,and the train travel speed is much faster than the general natural wind speed,the surface pollution process of the roof insulator becomes more complicated.This paper takes the modified FM400 roof insulator widely used in CRH380 series models as the research object,combined with the climate and environmental conditions along the Beijing-Shanghai high-speed railway,to study the surface area pollution characteristics and electric field distribution of the roof insulator.First,construct a three-dimensional model of the roof insulator,use COMSOL Multiphysics software for simulation,and support the built-in physics field and finite element calculation method to study the distribution of the high-speed airflow on the periphery of the roof insulator under the condition of high-speed train travel And the influence of the deposition of pollutant particles;the influence of specific factors such as the installation angle of the roof insulator,the particle size of the pollutant particles in the natural environment of the region,and the magnitude of the applied AC voltage on the change rule of the pollution characteristics of the insulator are studied;Combining the research results to further analyze the impact of high-speed airflow and particle size changes on the flashover characteristics of the insulator,and put forward anti-pollution flashover measures.The distribution characteristics of the electric field along the surface is an important factor affecting the insulator flashover.Based on the above simulation study of pollution characteristics,and considering the uneven pollution distribution,a simplified two-dimensional model of the roof insulator was established,and the electric field distribution characteristics of the roof insulator along the surface were simulated and calculated.The distribution characteristics of the electric field along the surface of the roof insulator in the dirty state and the clean state are compared.The analysis of the electric field distortion of the roof insulator in the dirty state is mainly analyzed.The electric field along the surface is the most concentrated and the distortion is the most serious.Based on this,measures for reducing electric field distortion are proposed.The research results show that: under high-speed airflow environment,the amount of dirt accumulated on the roof insulator is mainly affected by the drag force of the airflow,and the accumulation of dirt on the leeward surface is mainly affected by the vortex generated by the surrounding flow.,So that the possibility of pollution flashover becomes greater;the distortion of the peripheral flow field causes the uneven distribution of the pollution layer on the surface of the roof insulator,resulting in distortion of the electric field along the surface of the insulator;due to the fact that pollution and high field strength are concentrated in the high-voltage end region of the insulator,making this Discharge is more likely to occur in parts,so it is recommended that when formulating roof insulator anti-pollution flashover measures,special attention should be paid to the cleaning of the high-voltage end umbrella skirt to minimize the probability of pollution flashover.There are 46 figures,6 tables and 82 references in this paper.