SF6 gas is the main arc-extinguishing medium for high-voltage circuit breakers. It has excellent characteristics such as electronegativity and high medium recovery strength. But as a kind of greenhouse gas, it has a very high greenhouse effect. Finding alternative gas for SF6 and ensuring reliable arcextinguishing have gradually become a hot spot in the field of high-voltage switches. Basing on the magnetohydrodynamic equations, a model of SF6 circuit breaker nozzle is simplified in this paper. Under the condition of local thermodynamic equilibrium, the process of arc formation in air, nitrogen, argon and SF6 under the same breaking condition are simulated in this paper. The influence of breaking current on arc characteristics is also analyzed. It provides a reference for the research work of SF6 substitute gas.
Keywords SF6 substitute gas, MHD model, arc, circuit breaker