Simulation Research On Electric Field Distribution Along Catenary Insulator In Haze Environment

With the continuous improvement of infrastructure construction and the further improvement of the level of industrialization,China’s economy has got an unprecedented development,but the resulting environmental pollution problems are becoming increasingly serious.In recent years,fog-haze weather occurs frequently.The effects of fog-haze weather on the external insulation of electrified railway power supply equipment can not be ignored and has become the focus of attention.At present,the research on the influence of haze particles on the external insulation of the railway catenary is in the initial stage,especially the analysis of the electric field distribution of the insulator by simulation.In view of this,this thesis explores the problem of the distribution of the electric field along the surface of the insulator by establishing model in the software and analyzing the characteristics of the electric field along the surface of the insulator.The conclusion can be used to study the cause of the composite external insulation flashover accident in the haze environment.In this thesis,the FQBG-25/12 insulator,which is commonly used in the catenary,is chosen as the research object.The simulation model of the mixed haze particles in the surrounding air is established in the electrostatic field.The simulation model of the insulator surface area is established in the quasi-static field.In view of the finite element method must be calculated in a finite area,the artificial truncation method is used to transform the infinite domain to a finite field,so as to meet the requirements of finite element method.Because of the large concentration of haze particles in the model to be established,and its size is different from that of the insulator geometry,it is necessary to simplify the model reasonably to ensure the efficiency and accuracy of the solution.The finite element software COMSOL Multiphysics is used to simulate and analyse the distortion of the electric field along the surface of the insulator under two different conditions,such as suspended fog-haze particles and deposition of water drops.The conclusion is that the haze particles in the air have little effect on the strength of the electric field along the surface of the insulator.The charged fog-haze particles is significant for the distortions of the electric field along the surface of the insulator.When the absolute value of the charge increase,the degree of distortion increased correspondingly.The effect of different charged polarities on the surface field strength of insulators is different The effect of the negatively charged particles on the electric field is greater than that of the positively charged particles.The effect of the positively charged particles on the electric field at the low pressure of the insulator is greater than that of the negatively charged particles.When the surface of the catenary rod-column post composite insulator is attached to the uniform contamination layer,the local potential of the contamination layer where the contamination layer is in contact with the insulator is constant,and the electric field is abruptly changed at the junction with the insulator.The water droplets attached to the column are more likely to have a greater effect on the electric field distribution of the insulator than the water droplets on the surface of the umbrella skirt.When the water droplets appear on the column,the electric field between the water droplets will be greatly enhanced;the effect of the number of water droplets on the maximum value of the electric field along the insulator is more obvious,the more water droplets,the stronger the field strength.