Dynamic Simulation Of Surface Charge Accumulation Of Composite Insulator Under Polluted Condition

Composite insulators are widely used in high voltage transmission lines in the polluted area due to their good anti-fouling properties,but for the composite insulators in the atmospheric environment,because of their long-term exposure to the natural environment,the dirty particles in the atmosphere can be deposited on the surface of the insulator's umbrella and form a layer of pollution on the surface of the insulator's umbrella,the existence of pollution layer can seriously affect the insulation performance of insulators.The electric conductivity of insulator under polluted condition will change under different weather conditions,it is possible to accumulate surface charge on its surface.Since surface charge changes the electric field distribution along the surface of the insulator,and will participate in the in-sulator pollution flashover process.Therefore,it is of great significance to study the related problems of surface charge accumulation of insulators under polluted condition to ensure the safe and stable operation of transmission lines.This paper deals with the suspension composite insulator FXBW4-10/70 which is applied in the polluted area,it mainly study that influence of the dirty particles on the surface charge accumulation when the dirty particles attached to the surface of the insula-tor's umbrella.Firstly,the dynamic accumulation model of the surface charge of insulator under the pollution condition was established by using the finite element simulation software COMSOL.The air flow field around the insulator was simu-lated by using the k-? turbulence model,the distribution of air flow field around the insulator can be obtained by solving the equation of momentum conservation and the continuity equation of mass conservation.The electric field in space is modeled by AC/DC module,the electric potential distribution is obtained by solving the current conservation equation.The particle tracking module and Newton's second law can be used to simulate the trajectory of the polluted particles in the flow field.And the surface charge density can be obtained according to the interface condi-tions of electric field.Then the influence of different factors on the surface charge distribution of the insulator's umbrella was analyzed under the effect of AC and DC voltage by using the model established in this paper.The specific conclusions are as follows:When the AC voltage is applied,for the insulators used in this article,when the wind speed is at 3.3m/s,the higher the conductivity,diameter and concentration of the particles,the more charge is accumulated on the surface of the insulator's umbrella.When the wind speed changed,the amount of charge accumulated on the surface of the insulator's umbrella increases with the increase of the wind speed,and then decreases with the increase of the wind speed.When the wind speed increased from 1.5m/s to 5.4m/s,the amount of charge accumulated on the surface of the insulator's umbrella increased with the increase of wind speed.When the wind speed increased from 5.4m/s to 7.9m/s,the amount of charge accumulated on the surface of the insulator's umbrella decreased with the increase of wind speed.At the wind speed of 5.4m/s,the surface of the insulator's umbrella accumulates the most charge.When the DC voltage is applied,for the insulators used in this article,when the wind speed is at 3.3m/s,the higher the conductivity,diameter and concentration of the particles,the more charge is accumulated on the surface of the insulator's umbrella.When the wind speed changed,dirty particles are easier to attach to the surface of the insulator's umbrella because of the unidirectional electric field force,when the wind speed increased from 1.5m/s to 7.9m/s,different from AC voltage,the amount of charge accumulated on the surface of the insulator's umbrella increases with the wind speed.