Contamination and AC pollution flashover characteristics of insulators under fog-haze environment

With the acceleration of urbanization and the rapid development of industry and agriculture, fog-haze occurs frequently in most parts of China, which is a serious threat to the safe operation of the power system. The effects of fog-haze on the insulators represent in two aspects: a) increasing contamination on the surface of insulators and b) increasing the leakage current and decreasing the flashover voltage of insulators due to the wet deposition. Therefore, in this paper, naturally polluted insulators under fog-haze were taken as test objects, and the contamination and AC pollution flashover characteristics of different kinds of insulators were studied. According to the test results, contamination on the insulator surface is increased significantly under fog-haze in a short time. Compared with porcelain and glass insulator, the composite insulator shows more serious contamination under fog-haze environment. Saturated moisture time of two-shed type porcelain insulator is the shortest and saturated moisture leakage current of that is the largest, while composite insulator has the longest saturated moisture time and the smallest saturated moisture leakage current. Composite insulator is with the largest flashover voltage gradient, which is followed by bell type porcelain insulator and deep under-rib type glass insulator, and that of two-shed type porcelain insulator is the smallest among these insulators.