Dielectric breakdown properties of SF ₆-N ₂ mixtures in the temperature range 300-3000K

Reduced critical electric field strength (E/N) _cr is an important indicator for the evaluation of dielectric breakdown of SF ₆ and its mixtures. This paper aims to analytically investigate the dielectric breakdown properties of SF ₆-N ₂ mixtures. First, (αη)/N and (E/N) _cr of SF ₆-N ₂ mixtures at room temperature, and then (E/N) _cr of hot SF ₆ at several pressures are calculated and compared with other studies. The results confirmed the validity of the present calculation method and parameters. In addition, the electron energy distribution function, reduced ionization coefficient α/N and attachment coefficient η/N of SF ₆-N ₂ mixtures are obtained at different proportions and under 1atm in the gas temperature range 300-3000K. Then (E/N) _cr can be determined when the effective ionization coefficient (αη)/N=0. The results show that in a certain temperature range, due to the effect of N ₂ on reduction in the proportion of high-energy electrons, (E/N) _cr of SF ₆-N ₂ mixtures will be enhanced by increasing N ₂.