From the microscopic point of view

the electron temperature and heavy particle temperature in the SF6 arc plasma are calculated with the Coulomb collision model.The Saha equation and the Guldberg-Wagge equation are modified according to the thermodynamic non-equilibrium state characteristics.According to the ionization existing in the SF6 discharge to conduct deionization balance calculation

the electron number density for different pressure and temperature is obtained.The calculation model of Spitzer conductivity is improved to obtain the conductivity of SF6 arc plasma in non-equilibrium state in the condition of 300～20 000 K and 0.1～1 MPa

and the result is compared with the calculated equilibrium state arc conductivity at pressure of 0.6 MPa.It is shown that at 7 000 K electrons begin to appear inside the plasma and the electron density rapidly reaches the peak with the increase of the temperature.When the pressure is 0.6 MPa and the temperature is lower than 10 000 K

the calculation difference of the conductivity between the non-equilibrium dual-temperature plasma and the equilibrium plasma are large because in the non-equilibrium state the electron temperature and the heavy particle temperature are quite different.Therefore

the development of the two different kinds of particles cannot be simultaneously characterized by single temperature.The non-equilibrium dual-temperature arc plasma model can describe the dynamic development of arc more accurately when ionization is insufficient in the plasma.These research results can be applied to the numerical calculation of the airflow field with small breaking current for such as filter-bank and capacitor-bank circuit breakers.