SF6 Alternative Gas Lightning Impulse Insulation Breakdown Characteristic in Medium Voltage

Sulfur hexafluoride (SF6), a greenhouse gas, is used as an insulating medium for power equipment due to its excellent insulating properties. However, as global warming and climate change become a global concern, the development of products that minimize the environmental impact is increasing, and SF6 replacement gas is being studied as an environmentally friendly alternative. Currently, there are N
2
, CO
2
, and fluorine mixed gas as substitute gas of SF
6
in medium voltage classes, and research on insulation characteristic for substitute gas is actively proceeding. In this paper, we present the results of a comparative study of breakdown voltage of C
5
F
10
O/CO
2
and SF
6
gases under lightning impulse voltage in a sphere-to-plate electrodes arrangement. The equivalencies between breakdown voltage of SF6 and those of SF6 replacement gases with respect to pressure and percentage of SF
6
and C
5
F
10
O/CO
2
are presented and discussed.