Simulation of Electrical Breakdown Characteristics of Eco-Friendly $\mathrm{C}_{4}\mathrm{F}_{7}\mathrm{N}/\text{CO}_{2}$ Gas Mixture

The greenhouse effect caused by <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\text{SF6}$</tex> in the power industry has become an increasingly pressing issue, leading to a growing focus in recent years on eco-friendly alternative gases such as the C4F7N/CO2 mixture. This paper investigates the electrical breakdown characteristics of eco-friendly <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mathrm{C}_{4}\mathrm{F}_{7}\mathrm{N}/\text{CO}_2$</tex> mixed gas through numerical simulations. Electron transport parameters are calculated based on the Boltzmann equation, and a fluid dynamics model is introduced to simulate the spatiotemporal evolution of charged particles and the electric field distribution in the needle-plane electrode gap. The results indicate that during corona discharge, the maximum electron density always appears at the tip of the needle electrode, whereas, in streamer discharge, the electron density gradually increases from the needle electrode to the streamer head. By iteratively solving based on this characteristic, the breakdown voltage can be determined. The findings of this study provide a reference method for quickly predicting the insulating properties of C4F7N/CO2 mixed gas under different conditions and offer theoretical foundations for developing eco-friendly insulating equipment.