A study on CF3I-Ar and CF3I-Kr mixture gases substituting SF6 in high voltage equipments

Tóm tắt

The present binary mixtures of the SF₆ gas with Ar and Kr gases have not been used in many industries as long-term measures for totally eliminating the potential contribution of SF₆ to global warming. In order to gain more insight into electron transport coefficients in mixture gases as substitutes for SF₆ in high voltage equipment, transport coefficients such as electron drift velocity, density-normalized longitudinal diffusion coefficient, ratio of the longitudinal diffusion coefficient to the electron mobility, Townsend first ionization coefficient, electron attachment coefficient, and density-normalized effective ionization coefficient in CF₃I-Ar and CF₃I-Kr mixture gases are calculated and analyzed in the wide E/N range of 0.01 – 1000 Td using a two-term approximation of the Boltzmann equation for the energy. These calculated coefficients are analyzed and compared to those in pure SF₆ gas. The limiting field strength values of E/N, (E/N)_lim, of these mixture gases are also derived and compared with those of the pure SF₆ gas at different percentages of CF₃I and SF₆. The mixture gases of 70% CF₃I with Ar and Kr have (E/N)_lim values greater than those of the pure SF₆ gas. Therefore, these mixture gases could be considered to substitute SF₆ gas in high voltage equipment.