Modeling of Ablation-Controlled Arc Plasma in a CO2 Mixture Circuit Breaker

In this paper, the design of a 72.5 kV CO
2
mixture gas circuit breaker (CB) and the results of its interruption capability tests were presented. The interruption capability of a short-line fault (SLF; L90) was tested. This study developed a technique to analyze CO
2
arc plasma, which was then applied to the design of a CO
2
CB. The interruption capability of CO
2
gas was just 20–30% that of SF
6
gas. Therefore, this study applied ablation elements and dual motion operation to the design of a CB to improve the interruption capability. To determine the interruption capability of the designed interrupter of the SLF, arc conductance and post arc current (PAC) at G200 (200 ns prior to current zero) were employed. Using the index of interruption capability, the design parameters of the interrupter, such as the volume of the compression chamber, the volume of the thermal chamber, nozzle configuration, and heating channel, were improved. The interrupter verified through analysis was fabricated, and its interruption capability was tested successfully using a simplified synthetic test facility. Furthermore, the tests prescribed by the certification institution were also performed successfully.