Investigation of hot gas flow in a dead-tank-type gas circuit breaker

This paper describes the behavior of hot gas flow during a large current interruption, which may cause a ground fault in a dead-tank-type gas circuit breaker even if hot gas is locally distributed between live part and grounded tank. By observations with high-speed-video and measurements of breakdown voltage with small gaps it became clear that gas temperature and electrical field strength at the mouth of exhaust tube are decisive to ground fault occurrence. How to avoid a ground fault and to efficiently select the optimal dimensions of an exhaust tube for a compact and reliable dead-tank-type GCB is shown.