Abstract

Abstract The substitution of SF 6 in gas-insulated electrical equipment has become a hot issue in the electrical field, and the research on the green medium C 4 F 7 N and its gas mixture has attracted much attention. In this paper, the molecular dynamics simulation method was used to analyze the C 4 F 7 N and CO 2 mixed insulating gas system in situ, and quantitatively simulate the concentration distribution, root mean square displacement, intermolecular interactions, and thermodynamic parameters of the insulating gases under the macroscopic conditions of different mixing ratios, pressures, and so on. The results show that by increasing the proportion of C 4 F 7 N at 298 K and 0.6 MPa, the mutual attraction between C 4 F 7 N and CO 2 molecules is enhanced, which leads to the decrease of the diffusion rate of the two gases, and the gas distribution is uniform without obvious delamination phenomenon, which reflects the good compatibility. At the same time, the increase of the mixing ratio of C 4 F 7 N increased the adiabatic and isothermal compression coefficient of the gas mixture at 0.6~0.8 MPa accordingly, and the gas mixture did not show liquefaction phenomenon. This study provides a certain basis for designing the mixedinsulating gas ratios to meet engineering needs.