Investigation of voltage and potential gradient of arc column in fluorocarbon gas and its gas mixtures

Because of its high dielectric strength, good partial discharge capability, low global warming potential (GWP), none ozone depletion potential (ODP) and non-toxicity, fluorocarbon gas is a possible substitute for SF6 gas, and can be used hopefully in electrical equipment, such as GIL, C-GIS. Arc voltage and potential gradient are useful in arc modeling and computational investigation of gas insulated apparatus, such as cubical-gas insulated switchgear (C-GIS), and the potential gradient can be used to estimate the arc energy generated in short current fault. In this study, voltage and potential gradient of arc column in fluorocarbon gas and its gas mixtures with different fluorocarbon ratios were measured. The experiment was performed on a single frequency oscillating-loop. It is shown that the arc voltage of fluorocarbon gas and its gas mixture increases with arc length. Moreover, the arc potential gradient was obtained based on the arc voltage and arc length. The arc voltage gradient decreases with peak arc current. Besides, as the mixture ratio of fluorocarbon gas increases, the arc voltage gradient becomes lower. At last, these results are compared with SF6 gas; it shows that the arc voltage gradient of fluorocarbon gas is bigger than that of SF6 gas. These results will provide a hopeful reference for future studies of fluorocarbon gas mixture C-GIS.