Improvement of outdoors insulation performance for application in highly polluted area by using silicone coatings

This paper describes the results of the investigation on the application of silicone compound coating of ceramic high voltage insulator in tropical environments. The effects of temperature, humidity and various artificial pollutants were investigated. The experimental results show that application of silicone compound coatings suppressed leakage currents significantly under contaminated environment. The hydrophobicity of the insulators was also improved drastically. The coating on the wet-polluted insulators results in a very poor improvement of the insulator properties. This showed coating method affected the performance of the coating. A SEM of the surface of the insulator surfaces revealed the correlation between the improvement of the ceramics insulator surface and the electrical properties. Degradation of the coating under long term voltage application was observed in the form of bubble which prevent the coating to tightly coat the insulator surfaces. A flashover on the silicone coatings was observed under SEM as a discharge paths on the coatings.