Letter to the Editor: Variation of Leakage Current with SDD on an Artificially Polluted Porcelain Pin Insulator—An Experimental Study

Abstract

Working insulators begin to fail as airborne contaminants and moisture from natural wetting combine on the surface of insulator to cause an increase in surface conductivity. This enables current to conduct across the insulators, thereby changing the electrical conductivity exhibited by the insulators when clean. If the change in conductivity is severe enough, then the leakage current may escalate into a service interruption due to flashover. This flashover results in an outage that in turn degrades power quality and hence affects reliability. To improve power quality, it is necessary to select proper insulator(s) depending on the level of the pollution. The leakage current mainly depends on salt deposit density (SDD) on the insulator surface, but this dependency is not yet investigated completely. This work is an attempt towards this direction, to study experimentally the variation of the leakage current with SDD. Experimental results reveal that the peak value of the leakage current remains almost same in magnitude for different SDD values and the time of occurrence of the leakage current peak is delayed for lower values of SDD.