Electrical Property Repair of Silicone Rubber Insulation by Atmospheric Pressure Plasma

This study explores the use of atmospheric pressure plasma jet (APPJ) technology to repair surface defects in silicone rubber (SIR) insulation, and aims at enhancing the electrical performance and service life of high voltage electric power equipment. SIR insulation is susceptible to damage and produce micro-cracks from harsh environmental conditions. An APPJ system is employed for plasma repair experiment, in which hexamethyldisiloxane (HMDSO) is used as the reaction precursor and argon (Ar) as both the carrier gas and the working gas. Experiments are conducted on SIR samples extracted from high-voltage cable terminals. The Fourier transform infrared (FTIR) spectroscopy is used to analyze the surface chemical composition of the SIR samples before and after plasma repair. The surface potential decay, volume resistivity, surface flashover strength and breakdown field strength are all tested to evaluate the electrical characteristics. The results show that the Si–C and Si–O groups are deposited on the SIR sample and fill the surface defects. Meanwhile the surface and bulk insulation performance is restored and enhanced after plasma repair. In addition, the corona aging results indicate that the plasma-repaired SIR insulation exhibits superior resistance to corona compared to untreated samples.