Performance analysis of silicone rubber insulator in DC high-voltage inclined plane tracking test

Abstract

The present trend in electric power transmission technology evolves with the latest high-voltage direct current (HVDC) transmission network. Silicone rubber (SiR) composite insulators are predominantly used since two decades for high-voltage alternating current (HVAC) transmission lines. In case of HVAC transmission line, the performance of SiR insulators is promising; however, there are failures reported with their uses for HVDC transmission line. In this research work, SiR composite formulations are varied to study their effective changes in the direct current (DC) tracking and erosion resistance. Four different weight percentage (wt%) aluminum trihydrate (ATH) fillers loaded SiR formulations are prepared and invariably subjected to positive polarity DC inclined plane tracking (DCIPT) test before and after ultraviolet (UV) aging. The Fourier transform infrared spectroscopy study has been carried out to understand their morphological changes after and before UV aging. The results of these tests indicated that DC tracking and erosion resistance effectively reduced severe surface degradation for UV-aged SiR material. However, the 40 wt% ATH-filled SiR sample performed well exhibiting higher time to failure in positive DCIPT and thus could be better usable as HVDC insulation material.