Analysis of dielectric breakdown of SF6 gas circuit breaker during large current interruption

This paper presents the analysis of the dielectric characteristics of hot SF₆ gas in the gas circuit breaker. Hot gas flow is analyzed using the finite volume method-based CFD code considering the moving boundary, material properties of hot SF₆ gas, and arc model. In the arc model, the re-absorption of the emitted radiation is approximated with the boundary source layer where the re-absorbed radiation energy is input as an energy source term in the energy conservation equation. The breakdown performance of the hot gas is predicted using the critical breakdown field and the applied field intensity. The analysis method is applied to the gas circuit breaker with different shield shapes and the results are compared.