Influence Of The Structure Of Oversize Umbrella Skirt On The Pollution Characteristics Of Composite Insulators

Composite insulators have received extensive attention in the field of transmission lines in recent years due to their easy installation,good pollution resistance and fast production cycle.However,with the increasingly serious environmental problems brought about by the rapid industrial development,the pollution flashover accidents of composite insulators are often reported.The structure of large umbrella skirt can increase the creepage distance of composite insulator,improve the surface pollution,and then improve the safety performance of power system.Therefore,it is necessary to study the influence of the structure of super-large umbrella skirt on the pollution accumulation characteristics of composite insulators.This paper briefly describes the wind tunnel pollution test of composite insulators in our university.Comsol software is used to simulate the pollution condition of composite insulators under the wind tunnel test conditions,and the comparison with the test results is made to verify the feasibility of the simulation method.The original model based on the FXBW4-110/100 composite insulator,as well as the model 1,2 and 3 with the extra large umbrella structure are first constructed in order to improve the pollution deposition on the surface.In this way,the flow field and electric field distribution of the super-large umbrella skirt and the original model are compared and analyzed,and their pollution accumulation law under different wind speed,particle size,concentration and voltage type is revealed.In addition,the distribution characteristics of pollution deposits on the upper and lower surfaces of the large umbrella skirt and the original structure model are also explored.The results show that:1)among the original model,model 1,model 2 and model 3,model 1 has the best aerodynamic characteristics,so adding a large umbrella skirt at an appropriate position can improve the flow field distribution of the composite insulator.2)When the size of the super-large umbrella skirt and the number of pieces are small,the DC electric field distribution of the composite insulator hardly changes.3)Under the same particle size,the pollution accumulation of composite insulators in both the super-large umbrella skirt structure and the original umbrella skirt structure increases with the increase of wind speed,and the greater the wind speed,the more obvious the effect.4)Except for high wind speed and high concentration(3m/s,0.45mg/m~3),the pollution volume of model 1 of super-large umbrella skirt structure is all lower than that of the original model.5)When the concentration is 0.15mg/m3,the amount of pollution in each particle size of the super-large umbrella skirt structure model is all lower than the original model;Under the condition of particle size d_p>25μm,the fouling amount of model 2 and model 3 is less than that of the original model.6)Under the action of DC voltage,the amount of pollution in Model 1 of super-large skirt structure is significantly smaller than that in the original model at low wind speed,and the difference decreases with the increase of wind speed.The amount of pollution in Model 2 and Model 3 is not significantly different from that in the original model.7)Under the action of AC voltage,the pollution accumulation amount of the first model of the super large skirt structure model fluctuates up and down in the original model,and the pollution accumulation amount of the second and third models differs greatly from the original model.