Study of anti-icing performance of insulator strings bottom-coated with semiconductive silicone rubber coating

Prevention of icing flashover on transmission lines has become an important problem. A new method for mitigating effects of glaze ice on energized insulators has been developed. Semiconductive silicone rubber was painted on the bottom of suspension disc insulators, while the upper ceramic surface was untreated. An electrically conductive path was formed when supercooled water or droplets bridged the uncoated areas. The power loss was limited when there was no precipitation. The heat and partial discharge energy generated by the leakage current melted the original ice accretion on the insulator surface. The electrical performance of the insulator string with this kind of coating under freezing rain conditions was comparable with that of a clean insulator string. The impact of the ambient temperature on the anti-icing performance was also evaluated. In addition, the performance of the insulator with bottom surface semiconductive coating under fog conditions was compared with an uncoated string.