PERFORMANCE OF HIGH VOLTAGE OUTDOOR POLYMERIC INSULATORS UNDER DIFFERENT POLLUTED CONDITIONS

Abstract

Insulation contamination has become a major problem in the operation of electrical power systems. In wet condition disruptions of the power system can occur. When an insulator is polluted and subjected to wetting in humid conditions, the service poweF-•" frequency voltage causes a leakage current to flow on the surface of that insulator. The leakage current has a thermal effect which causes evaporation of some of the water content of the pollution layer. Dry bands will establish and this will cause partial arcs, which may lead to flashover under certain conditions. If the leakage current is minimized or stopped, the bands will not exist and no flashover can occur. fAis work presents the effects of sandstorms on the polymeric

materials, which are widely used for outdoor insulation applications. Moreover, the experimental results of a study carried «;\\'It to examine the environmental effects of sandstorms, ultraviolet and high temperature on the electrical performance of silicone rubber insulators (SR) are thoroughly investigated. The characteristics of outdoor polymeric insulators subjected to natural pollution in desert areas compared with the characteristics of the well known conventional ones (porcelain and glass) were also investigated. The comparison is mainly devoted to, the ability of