2-D Simulation of Cathode-Directed Streamer in SF6/N2 Gas Mixtures

Abstract

SF6 has been widely used in the power industry as an arc quenching and insulation medium due to its excellent physical and chemical properties since 1960. However, experience shows that SF6 gas medium has many disadvantages under certain conditions: gas may encounter liquefaction when installed in cold areas; SF6 is still expensive; dielectric strength is sensitive to electric field, and require higher equipment design and manufacturing processes; SF6 is a greenhouse gas, and is used under limitations since the Kyoto Protocol was signed in 1997[. Unfortunately, its difficult to find no environment hazards and to replace SF6 completely at present. In view that the greenhouse impact of SF6 is still very little (it is estimated less than 0.01%) in the atmosphere recently and it does not damage the ozone layer, it becomes a focus to find gas mixtures containing SF6 to replace pure SF6 gas to reduce the emissions and environmental impact of SF6. Scientists from all countries and international major GIS manufacturers, electric power sector are working together to develop new gas mixture of SF6-insulated electrical equipment [2].