Effect of puffer volume and operating force on dielectric recovery performance in thermal puffer-type gas circuit breaker

In order to investigate the influence of puffer volume V_P and operating force to dielectric performance of GCB at current interruption, we calculated the prospective dielectric withstand voltage V_W between arcing contacts. The withstand voltage was calculated by the electric field strength appeared on arcing contacts and the allowable electric field strength E_W^* of hot gas due to thermal puffer action. We could clarify that large initial puffer volume V_P can increase withstand voltage V_W at current breaking point and also that an optimum point exists in operating force F. For example, it was found that in case of the operating force of 1000 kgf, the puffer volume V_P of 1.2 liter would be best choice in the interrupting condition of i=50 kA and arcing time of 1.35 cycle.