Insulation characteristics of CF3I/N2 gas mixtures and potential application in C-GIS

CF
3
I has been recognized as an attractive insulating medium for substituting SF
6
gas in high-voltage switchgear insulations, because it has low global warming potential (GWP) and an insulation capability that is 1.2 times greater than that of SF
6
. In this paper, the AC breakdown tests on CF
3
I/N
2
gas mixture have been completed in a sphere-plate geometry. We reveal the effect laws of mixture content, gas pressures, and gap distances. The results indicate that the insulation strength of the CF
3
I/N
2
gas mixture will be efficiently improved by prolonged insulation distance and higher gas pressure. And the insulation ability of the CF
3
I/N
2
gas mixture were demonstrated in a 12kV C-GIS designed for SF
6
gas when the gas is replaced with Alternative Gas.