The research on effect of nozzle throat diameter of high voltage SF6 circuit breaker on breaking capability

The nozzle structure of circuit breaker has a direct influence on the flow of blowing arc gas. Based on equation of N-S, the flow field and the electric field in the arc chamber which has different nozzle throat diameters without load are calculated and simulated in this thesis. The influences on the flow of blowing arc gas and the characteristics of dielectric recovery in SF₆ circuit breaker with different throat constructions are analyzed, compared with the distributions of pressure and density and the variety of dielectric recovery strength. Moreover, the influencing rules of throat diameter on the recovery strength are obtained, and the optimal throat diameter size of the circuit breakers with different structure is explored and acquired, which provides effective evidences for the design and improvement of the SF₆ arc chamber.