Insights on decomposition process of c-C 4 F 8 and c-C 4 F 8 /N 2 mixture as substitutes for SF 6

Abstract

In recent years, many scholars have carried out studies on c-C 4 F 8 and its gas mixture and found it has potential to be used as an environment-friendly insulating medium to replace SF 6 in medium-voltage equipment. In this paper, the c-C 4 F 8 and c-C 4 F 8 /N 2 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-C 4 F 8 /N 2 mainly produces CF 2 , F, CF 3 , CF, C, CF 4 and C 2 F 4 . c-C 4 F 8 can decompose to C 2 F 4 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-C 4 F 8 /N 2 mixture is better than that of pure c-C 4 F 8 at the same temperature. Relevant results provide guidance for engineering application of the c-C 4 F 8 /N 2 gas mixture.