Influence of Insulating Materials and Their Parameters on Surface Electric Field Intensity and Potential Distribution of Insulators

To research the influences of types and parameters of insulation material on electric field intensity and potential distribution of insulator,utilizing finite element method(FEM) and taking post insulator as the research object,the electric field intensity and potential distribution of insulator and adjacent region as well as the electric field and potential along insulator surface and dry arc path are researched while the material for the cylinder and shed of insulator is electric ceramics,glass and high temperature vulcanization(HTV) silicon rubber respectively.Meanwhile,the influences of resistivity and relative dielectric constant of insulation material on the field intensity and potential distribution at the region nearby the insulator are researched as well.Research results show that the distribution of field intensity and potential of post insulator is extremely non-uniform,at the position near upper flange the highest field intensity exists and where the potential is concentrated;from the top of the insulator to its bottom,there is a downward trend to the descent velocity of both field intensity and potential along insulator surface;basically,the integral field intensity,potential and equipotential line are not influenced by insulation material;according to the decreasing order of maximum insulator field intensity and potential concentration degree,the ranking of insulation material is as following: HTV,electric ceramics and glass.Shed makes nearby electric field distorted: at the junction of upper surface of insulator shed with the cylinder as well as at the position near the bottom of edges of the lower surface of the shed the distortion is relatively severe.Within normal range of volume resistivity of insulation material,its influence on field intensity and potential distribution are not observed;along with the increase of relative dielectric constant the maximum field intensity decreases,and the potential distribution along insulator surface and dry arc path becomes more uniform,however the electric field near the insulator shed is more distorted.