Li Zhibing

In order to meet the requirements of optimization design for SF6 circuit breaker under nonequilibrium conditions, it is very necessary to research the break-brake criterion velocity which can judge whether circuit breaker has interrupted successfully. This paper built up a simulation model of the 126kV SF6 circuit breaker, then got electric field and density distribution at different stages, and calculated dielectric recovery characteristic curves through the coupling of the electric field and flow field calculation. By compared critical breakdown voltage with transient recovery voltage under different break-brake speed, we analyzed how different break-brake speed affects the interruption of SF6 circuit breaker under nonequilibrium conditions. It is shown that if the break-brake speeds of less than 6m/s, the sample breaker occurred reignition phenomenon.