Insights on decomposition process of c-C4F8 and c-C4F8/N2 mixture as substitutes for SF6

摘要

In recent years, many scholars have carried out studies on c-C₄F₈ and its gas mixture and found it has potential to be used as an environment-friendly insulating medium to replace SF₆ in medium-voltage equipment. In this paper, the c-C₄F₈ and c-C₄F₈/N₂ gas mixture models were built to study its decomposition process by the combination of reactive molecular dynamics method and density functional theory. The yield of the main decomposition products, the reaction pathways and enthalpy under different temperatures were explored. It was found that the decomposition of c-C₄F₈/N₂ mainly produces CF₂, F, CF₃, CF, C, CF₄ and C₂F₄. c-C₄F₈ can decompose to C₂F₄ by absorbing 43.28 kcal/mol, which is the main decomposition path and this process easily occurs under high temperature. There is a dynamic equilibrium process among the various produced radicals, which ensures the insulation performance of system to a certain extent. The decomposition performance of c-C₄F₈/N₂ mixture is better than that of pure c-C₄F₈ at the same temperature. Relevant results provide guidance for engineering application of the c-C₄F₈/N₂ gas mixture.