A study of the insulation property for development of eco-friendly GIS under SF6/N2 mixtures

Abstract

Gas insulated systems are widely used in the electric power industry for transmission and distribution of electrical energy. When SF6 was first discovered, the potential application was only considered for insulation because of good dielectric properties. But the widespread use of SF6 gas by electric power and other industries has led to increased concentrations of SF6 gas in the atmosphere. This causes concern as to possible effects on global warming because SF6 is a potent greenhouse gas. This paper presents the dielectric strength and insulating property on SF6/N2 mixtures to make design criteria for developing the GIS. Two types of mixed gases (50%SF6_50%N2, 20%SF6_80%N2) were applied. We performed tests for electrode gap, contamination of particles, Triple junction for the spacer and earthing switch and disconnecting switch sections of GIS model. Test gas pressure is from 0.3 to 0.7 MPa. To find the 50% Breakdown voltage, the number of breakdown was performed 15 times and all test results were applied to analyze the normal distribution. The study was conducted to develop environment-friendly GIS under SF6/N2.