Investigation into the implementation of silicone coatings on high voltage insulators in Queensland

Corrosion of the pin of high voltage porcelain and glass cap-and-pin insulators, which is mainly caused by leakage currents, can severely compromise the mechanical integrity of the insulator, leading to a shorter service life. This paper investigates the potential for room temperature vulcanising silicone (RTV) coatings on high voltage insulators in Queensland. These silicone coatings are designed to improve the pollution performance of the insulators, reducing the leakage currents seen by the insulator. This in turn, would reduce the problem of pin corrosion. To effectively assess this potential, high voltage testing was performed on coated and uncoated insulators under artificial pollution conditions. It was found that silicone coatings reduced the leakage currents across the insulators, a conclusion that has been confirmed by others in the field. Along with this, a detailed cost analysis was performed, looking into the costs involved with installing and maintaining high voltage insulators in a large transmission network. Alongside this, the costs of silicone coatings were assessed, and from these costings, it was found that silicone coatings would only need to extend the service life of the insulator by a small margin to be cost effective.