Breakdown voltage characteristics in the SF6/N2 gas mixtures for DS/ES compartment of a 245kV gas insulated switchgear

Abstract

The SF6 gas insulated switchgear (GIS) is the electric power equipment for transmission and distribution line which reduced the size of the electric power equipments by installing in a sealed tank. Since the size of the GIS is about 1/10 of the air insulated switchgear, high quality insulation gas should be used. However this gas is a source of global warming and its production cost is very high because of expensive insulation material. Therefore, it is necessary either to develop a new relative gas: air and N2 gas or to reduce SF6 gas. The development of N2 mixture gas is needed when we consider safety and economic feasibility. In this study, a full scaled gas chamber for DS/ES compartment was designed and evaluated the breakdown voltage characteristics. In the mixing ratio of SF6/N2=50/50, insulation performance tests for DS/ES compartment for 245kV GIS were also conducted. By comparing and analyzing SF6 gas and SF6/N2 mixture gas, the results will be actually used as the standard reference of insulation design for eco-friendly 245kV GIS.