Dynamics of exhaust gas generated by arc extinction

We report an analytical study on hot gas exhaust process of a SF6 gas circu it breaker (GCB), after current interruption. The behavior of the hot gas h as been studied based on measured gas temperature and simulation results of gas composition. We also propose a mechanism of interaction between the ho t gas and pressure waves, which causes a self-blocking of the exhaust gas. During the heavy current interruption, the flow model suggests that the die lectric strength of the hot gas is affected by the pressure waves that are generated by the hot gas exhaustion. We believe that the results reported i n this article provide guidance for the optimum structure of the exhaust ch amber for small size GCB, operating at very high interrupting current. (C) 2001 American Institute of Physics.