Investigation of Arc Dynamic Behavior Change Induced by Various Parameter Configurations for C4F7N/CO2 Gas Mixture

This study investigates the feasibility of using a mixture of C4F7N/CO2 gases as an eco-friendly arcing medium for high-voltage circuit breakers, comparing its performance to that of conventional SF6 gas. An existing magnetohydrodynamic (MHD)-based arc model is modified to incorporate the non-recombination characteristics of C4F7N. The temperature, pressure, and velocity distributions of the arc throughout the whole arcing process are systematically analyzed. First, the differences in multi-physical fields induced by the C4F7N non-recombination feature are highlighted. The effects of varying the C4F7N concentration from 4% to 10% in the C4F7N/CO2 gas mixture on the arc behavior are also computationally studied. The results indicate significant differences in the arc-extinguishing performance between C4F7N/CO2 and SF6 under identical operating conditions. The potential of using C4F7N/CO2 as a viable alternative to SF6 in circuit breaker applications may need further design efforts to optimize key components such as the driving mechanism and nozzle. Moreover, as the concentration of C4F7N increases, the gas mixture exhibits improved flow field characteristics, suggesting that a higher volume concentration of C4F7N enhances the gas's short-circuit current interruption capabilities.