Abstract- Pollution induced flashover mechanism may pose a serious threat to reliable operation of high voltage bushings when exposed to various environmental conditions. Differences in the amount of pollution on the top and bottom surfaces in bushings may have great effect on surface flashover voltage and leakage current. Such pollution degrades the bushing and affects their electrical characteristics. In this paper bushing’s non-uniform pollution performance was studied. According to IEC60507 solid layer pollution method was used and laboratory based pollution performance test is conducted on bushing. Brushing method is adopted to coat the NaCl salt and kaolin mixture in different ratio with three equal intervals. Based on the artificial pollution test ESDD and NSDD levels are noted. Pollution is carried out for both normal bushing and RTV coated bushing. Based on test results it was found that the flashover voltage gets reduced when the T/B ratio increases and the performance of RTV coated bushing shows better results which inhibit the formation of continuous moist conductive layer.
Index terms – non-uniform pollution, flashover voltage, salt deposit density, RTV.
I. INTRODUCTION Now a day’s electrical energy plays a vital role in human life. Since at the end of the…show more content… Pollution is a main problem which affects the insulating material of bushing. It degrades the bushing and severely affects their electrical characteristics, being one of the main causes of mis-operation of the bushings. This pollution is one of the main causes of flashover in the bushings. The bushing begins to fail when the pollutants that exist in the air settle in the surface of the bushing and combine with the humidity of the fog, rain, or dew. Due to deposition of pollution, there is decrease in breakdown