Experimental Study on Performance of SF6+N2 Mixed Gas Insulation

Abstract

This paper designed and constructed a 126kV GIS partial discharge test platform, performed frequency breakdown tests and lighting impulse tests at temperature of -30~20℃to SF6/N2 gas mixture. The present experiment studied frequency breakdown tests in different temperatue and slightly inhomogeneous electric field, obtained change in frequency breakdown voltage as a function of temperature; Analysed positive and negative lightning impluse test in gas mixture, in which SF6 had a propotion of 30%~60%, in different temperature. Results indicated 50% probability breakdown voltage variation in positive lightning impluse tests, and in a low temperature environment, the breakdown voltage increased at negative lightning impulse, the polarity effects varied with condition of pure SF6 gas. The experimental results showed implement of SF6/N2 mixed gas with 30% SF6 supersedespure SF6 gas, could effectively reduce the consume of SF6, and remit greenhouse efect.