Experimental Study on the Insulating Property of the Gas Substituting SF6 in Gas Insulated Switchgear

Abstract

Through 126kV GIS partial discharging test platform independently designed and constructed, and taking the substitution of pure SF6 with SF6/N2 gas mixture as an example, this paper conducts power frequency impact breakdown and lightning impulse tests on SF6/N2 gas mixture within the temperature range of -30 ~ 20 ℃ , analyzes the power frequency withstand voltage test results of SF6/N2 gas mixture under different environment temperature conditions and slightly inhomogeneous electric field configuration, and obtains the change law of power frequency breakdown voltage with temperature variation; when the proportion of SF6 is between 30% and 60%, it analyzes the test results of gas mixture under different environment temperature conditions and the lightning impulse of positive and negative polarity, and gets the change law of 50% probability breakdown voltage in the lightning impulse test of positive polarity of SF6 gas mixture in different proportions; under low temperature environment, the breakdown voltage increases under the lightning impact of negative polarity, the polarity effect generated is contrary to pure SF6, and applying SF6/N2 gas mixture with 30% SF6 to substitute pure SF6 gas in engineering application can effectively reduce SF6 consumption and greenhouse effect.