Comparative studies of C4F7N-based gas mixtures as the eco-friendly alternative to SF6 for interrupting applications

To comprehensively evaluate the feasibility of using C₄F₇N-based gas mixture as arc extinguishing medium, a comparative study is performed on the variations of the multi-physical fields, gas flow environment and decomposition characteristics of the gas mixtures. A modified theoretical basis of the arc model developed for the C₄F₇N-based gas mixture is presented in the work with particular emphasis on the non-recombination features of C₄F₇N. This work also experimentally studies the electrical characteristics of the gas medium and the monitored parameters are also used to calibrate the arc model. The amount change of the seven dominant decomposing by-products is analysed as well. The results present that the C₄F₇N/CO₂/O₂ ternary gas mixture exhibits a more promising interrupting performance. Increasing the O₂ concentration from 5% to 10% has less effects on the arc characteristics, but it could suppress the formation of CO. The arc behaviour of C₄F₇N/CO₂/O₂ gas mixture is also improved with increasing the velocity of the moving components. The findings provide important insights into the potential of C₄F₇N-based gas mixtures as one of the sustainable and effective solutions for high-voltage interrupting applications.