Research on Breakdown Properties of Hot SF6/N2 Gas Mixture

In this paper, the electrical breakdown characteristics of hot SF
6
/N
2
mixed gas are studied. Under the assumption of local thermodynamics and chemical equilibrium, used the law of mass action to calculate the mole fraction of each component of the SF
6
/N
2
arc plasma with a pressure of 0.01MPa to 2.0MPa and a temperature of 4000K to 300K, analyze the variation process of each species composition of hot SF
6
/N
2
arc plasma with temperature and pressure during arc extinction. Using two approximate methods to solve the Boltzmann equation, the electron energy distribution function of the hot SF
6
/N
2
mixed gas under different electric fields is obtained. The reduced ionization coefficient and reduced adsorption coefficient of each microscopic species in different collision processes are analyzed, and the obtained The reduced breakdown field strength
$(E/N)_{\mathrm{cr}}$
of the hot SF
6
/N
2
mixed gas. The study shows that the reduced breakdown field strength
$(E/N)_{\mathrm{cr}}$
of the SF
6
/N
2
mixed gas increases with the decrease of the arc plasma temperature, and the rate of increase is mainly related to the composite characteristics of SF
6
in the mixed gas, increase pressure can effectively promote the recombination speed of SF
6
, thereby increasing the
$(E/N)_{\mathrm{cr}}$
of SF
6
/N
2
mixed gas; due to the higher decomposition temperature of N
2
, increasing the mixing ratio of N
2
can increase the mixed gas (E/N)
cr
in the temperature range of 3500K~2000K improves the electric breakdown characteristics of the mixed gas.