EFFECTS OF FILLER LEVEL IN RTV SILICONE-RUBBER COATINGS USED IN HV INSULATORS

This paper reports on the ability of room temperature vulcanizing (RTV) silicone rubber insulator coatings to suppress leakage current, thereby preventing power outages due to contamination. The RTV coatings were applied to porcelain suspension and line post insulators for a comparative study of the performance of coated and uncoated insulators. A study of the role of alumina trihydrate (ATH) which is used to impart tracking and erosion resistance to RTV coating is reported. A study of the diffusion of silicone fluid from the bulk to the surface of the RTV silicone rubber having various ATH filler levels using attenuated total reflection (ATR) Fourier Transform Infrared (FTIR) spectroscopy is also reported. It has been found that the diffusion rate of the silicone fluid from the bulk to the surface of the coating after extensive dry band arcing decreases with increasing filler level.