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