DefinePK

Abstract

In recent decades, overhead insulators play a major role in electrical distribution system for transmitting power through transmission line over long distances owing to its high insulation strength. Nonetheless under contaminated conditions, insulation strength decreases due to rise in pollution levels of environment. Hence, it is required to check the ability of the insulator by artificial test approaches in polluted situations. This paper deals with the performance on high voltage 11 kV rated overhead insulators of polymer and porcelain type under contaminated conditions based on IEC 60805. Insulators are contaminated with suitable proportions of NaCl and applied uniformly on the surface. In this study, tests are carried out on insulators under power frequency to check for the withstand voltage test, lightning and switching impulse withstand voltage tests with negative impulses. It is clear from the experiments done on the insulators that flashover occurs at lesser voltages when the pollution level is high which in turn increases conductivity. The relation between leakage current and applied voltage, under different fixed levels of pollution is observed.