Abstract:

Physicochemical properties of trifluoromethanesulonyl fluoride（CF₃SO₂F） dielectric medium， which is a promising eco-friendly insulation gas to replace SF₆ for the high-voltage electric applications， were calculated using molecular dynamics simulations. An optimized mPCFF force field was proposed and validated on the basis of the theoretically predicted molecular structures， internal rotation， dipole moments， and vibrational frequencies， which were in good agreement with the experimental and quantum chemical data. The physical properties of CF₃SO₂F in the phase envelope including vapor pressures， densities， heat capacities， enthalpies of vaporization， critical properties， together with the key transportation parameters including self-diffuse coefficients， dielectric constants， shear viscosities， and thermal conductivities， were examined systematically for the first time in the temperature range 243—323 K. In addition， the gas mixtures of CF₃SO₂F with N₂ or CO₂ buffer gas were investigated to compare with the electrical performance of SF₆ and C4/CO₂. A few critical suggestions on the use of CF₃SO₂F were proposed in terms of mixing ratio， liquefaction temperature， self-diffuse， and thermal conductivity for the purpose of realistic electrical applications.

Key words: Replacement gas for SF₆, Trifluoromethanesulfonyl fluoride, Physicochemical property, Force field, Molecular dynamics simulation