Breakdown Electric Field of Hot 30% CF_3I/CO_2 Mixtures at Temperature of 300–3500 K During Arc Extinction Process

We calculated the uniform dielectric breakdown field strength of residual 30%CF_3I/CO_2 gas mixtures during the arc extinction process over the temperature range 300–3500 K at 0.1 MPa. The limiting reduced field strengths are decided by a balance of electron generation and loss based on chemical reactions estimated by the electron energy distribution function(EEDF), which employs the Boltzmann equation method with two-term expanding approximation in the steady-state Townsend(SST) condition. During the insulation recovery phase, the hot CF_3I/CO_2 gas mixtures have maximum dielectric strength at a temperature of about 1500 K. At room temperature 300 K, the electric strength after arc extinction(90.3 Td, 1 Td=10-21V·m2)is only 38% of the original value before arc(234.9 Td). The adverse insulation recovery ability of CF_3I/CO_2 gas mixtures in arc extinction hinders its application in electric circuit breakers and other switchgears as an arc quenching and insulating medium.