Investigation of Ablation Gas Transportation with Optical Emission Spectroscopy for Gas Circuit Breaker

Ablation in nozzle materials is caused by arc exposure during current interruption processes in high-voltage gas circuit breakers. To improve the performance of the interruption process, it is important to understand ablation gas distribution in the nozzle. The dielectric strength of ablation gas is less than that of SF6 gas, which is used as an arc quenching medium. Optical emission spectroscopy was carried out on a model circuit breaker to clarify ablation gas transportation in this study. The ablation gas transportation was estimated by using an emission spectrum of C2 molecules and sulfur ion. The arc consisted mainly of ablation gas during the large current phase. As the current decreased towards current zero, the SF6 gas flowed into the arc area from the puffer chamber and ablation gas flowed out of the nozzle.