Influence of Pollution Components on Surface Electric Field of Composite Insulators

Surface pollution of insulators is the main cause of pollution flashover, and the pollution components have different effects on the electrical performances of insulators. In order to study the influence of pollution components on the surface electric field of insulators, a simplified model of composite insulators was established by taking Golmud city along the Qinghai-Tibet Railway as the actual operation environment of insulators. It is found through simulation that when the contaminants are dry, their influence on the surface electric field of insulator follows the tendency from high to low as CaSO4＞KNO3＞NaNO3＞K2SO4＞NaCl＞MgSO4, which is mainly determined by the relative dielectric constant of the medium; when the contaminants are wet, their influence follows the tendency as sodium chloride ＞ nitrate ＞ sulfate, and the conductivity of each polluted liquid becomes the main factor affecting the electric field distribution. The hydrophobicity also affects the electric field distribution of insulators, and the overall electric intensity of insulator with drying zone is higher than that without drying zone. The simulation results were verified by the experimental results. The conclusion explains the influence of pollution components on insulator’s insulation performance from the perspective of electric field distribution, and can provide a new idea for regional pollution classification and insulator contamination test in laboratory.