Evaluation of Dielectric Interruption Performance in Gas Circuit Breaker with Ablated PTFE/BN Vapor

Gas circuit breaker (GCB) with reduced size and operating energy by using arc energy is developed. The puffer pressure increases by using the arc energy with the help of nozzle ablation; thus, high-pressure gas is blasted to the arc between the electrode gap. Sulfur hexafluoride (SF
₆
) gas is used as a quenching and insulating medium in a GCB. The content ratio of nozzle ablated vapor in SF
₆
gas is changed by nozzle ablation due to the arc energy and affects insulation performance after current zero. For this study, we analyzed the effect of nozzle ablation on insulation performance with critical electric field strength, which varies with the amount of ablated vapor. As a result, the critical electric field strength by considering nozzle ablated vapor decreased by 27% against that of pure SF
₆
. The effect of the filling material of the nozzle on insulating performance can be ignored when the content ratio of nozzle ablation vapor is less than 40%.