Simulation Of Influence Of Water Droplets On Electric Field Distortion And Contamination Deposition Characteristics Of Insulator Surface

Composite insulators are widely used in transmission lines due to their light weight,good stain resistance and load shock resistance.In recent years,with the environmental pollution caused by the rapid development of China’s industry and agriculture,the degree of contamination deposition on the surface of the insulator has been aggravated,especially in the humid weather such as fog,dew and drizzle,which has created conditions for the occurrence of pollution flashover accidents and seriously threatens the safe operation of the power system.Therefore,it is necessary to study the effect of water droplets on the electric field distortion and contamination deposition characteristics of composite insulators.In this paper,the FXBW4-x/100 composite insulators were used as the research object.Firstly,the electric field distortion was simulated under 10kV by COMSOL software when the surface of insulators was condensed with water droplets.The field strength and spatial electric field line distribution near the insulator were obtained.The effects of water droplet size,spacing,relative dielectric constant and electrical conductivity on the electric field distortion characteristics of the insulator surface were analyzed.Therefore,the deposition criterion was used to simulate the contamination deposition characteristics of the 110kV insulator under natural conditions,the simulation results of the flow field,field force and particle velocity response time were obtained and analyzed.The effects of wind speed,particle size,contamination concentration and voltage type on its natural contamination deposition characteristics were discussed when the surface of insulator was condensed water droplets or not,and the distribution of contamination deposition along the insulator skirt and upper and lower surfaces was obtained.The main results show that:1)the distance between the water droplets has the greatest influence on the distortion of the electric field on the surface of the insulator,and the distortion rate can reach 572.9%;the effect of water droplet size and relative dielectric constant of water droplets is weakened in turn,while water conductivity has little effect on the distribution of electric field on insulator surface.2)The electric field strength inside the water bead is much smaller than the surrounding electric field;and the electric field strength at the intersection of the water bead and the surface of the insulator and the air is significantly increased;The electric field strength between the beads is small in the middle and the ends are large.3)The presence of water droplets can increase the contamination deposition of the insulator surface.4)At the same contamination concentration,when the surface of the insulator is condensed with water droplets,the amount of accumulated dirt increases,and as the wind speed increases,the difference of the deposit amount gradually increases.5)Under the action of each voltage type,the deposit amount increases as the wind speed increases gradually,and the difference of the deposit amount under the action of DC and AC voltage gradually decreases.Besides,when the insulator surface is condensed with water droplets and the particle size is 20μm,the deposit amount under the action of the AC voltage even exceeds the deposit amount under the action of the DC voltage.6)The NSDD_DC/NSDD_AC is smaller than that of there is no water droplets on the surface of the insulator when the surface of the insulator is condensed with water droplets under the same conditions.7)Under the action of DC voltage,the deposit amount along the umbrella skirt is approximately“U”-shaped at the same particle while the wind speed is different.Under the action of AC voltage,the distribution of the deposit amount along the umbrella skirt has no obvious law.