Erosion/tracking resistance investigation of micro/nano-SiO<inf>2</inf> filled RTV-SiR composites for outdoor High Voltage insulations

Abstract

Research on micro and nano-dielectrics has shown that amalgamation of micro/nano particles into polymer usually enhances its mechanical, thermal and erosion/tracking characteristics. Due to organic-nature, silicone rubber (SiR) insulator outer sheath and weather-sheds are susceptible to environmental and electrical stresses, which lead tracking/erosion of outer surface. In this paper, we have investigated the amalgamation effects of micro and nano-sized silica (SiO 2 ) on the tracking and erosion resistance performance of SiR composites. SiR-blends with different weight percent (wt %) of micro/nano-silica were prepared in a two roll mixing mill according to ASTM-D 1418-10a standard. In order to evaluate the relative tracking and erosion resistance, all SiR-blends were analyzed in the initial-tracking voltage test method of the Inclined Plane Test (IPT) under AC voltage according to ASTM D-2303 standard. Moreover, the Infrared (IR) spectrum and maximum track temperature of SiR-blends were measured by using Fluke-Ti25 infrared (IR) camera. Initial tracking voltage (ITV), Leakage current (LC), percent erosion, time to track and maximum tracking temperature were investigated and discussed. Results showed that micro-silica filled SiR-blend (S2) exhibited higher tracking/erosion resistance, ITV∼2.75KV, time to track∼240 minutes and minimum eroded mass∼ 0.5% compared to neat and nano blends. The erosion/tracking results of SiR-blends suggest, that the tracking and erosion resistance of composite samples are governed by filler type, size and wt% in polymer matrix, which will provide potential for use as High Voltage (HV) insulation applications.