Electrical and thermal conductivities of high-temperature CO₂–CF₃I mixture and transient conductance of residual arc during its extinction process

Abstract

Fundamental properties of CO2 mixed with CF3I were investigated in terms of (i) electrical and thermal conductivities at temperatures up to 30 000 K, (ii) a decay process of an arc conductance around a current zero under a free transient-recovery-voltage condition and (iii) an arc extinguishing capability in a thermal re-ignition region. The electrical conductivity at temperatures below 10 000 K proved to increase gradually with the admixture amount of CF3I. The thermal conductivity, in particular around 7000 K, was found to have marked dependence on the CF3I concentration. The result for the decay process of the residual-arc conductance under the free transient-recovery-voltage situation showed that the arc conductance attenuated more rapidly for CO2 mixed with CF3I at concentrations above 0.9 than for pure CO2. The mixture gas having the same concentrations was also revealed to cause the arc to be extinguished under a higher transient-recovery voltage than pure CO2.

Breakdown Electric Field of Hot 30% CF3I/CO2Mixtures at Temperature of 300–3500 K During Arc Extinction Process

“…In the arc decaying process after current zero, equilibrium compositions of 30%CF 3 I/70%CO 2 gas mixtures at 0.1 MPa are calculated in Ref. [14] in the temperature range from 300 K to 3500 K based on the Gibbs free energy minimization. The molar fraction of each particle has been transformed from the number density-temperature curves [14] .…”

“…[14] in the temperature range from 300 K to 3500 K based on the Gibbs free energy minimization. The molar fraction of each particle has been transformed from the number density-temperature curves [14] . The mole proportion of each component mainly depends on the pressure and temperature of the gas condition (see Fig.…”

Dielectric characteristic of dichlorodifluoromethane (R12) gas and mixture with N 2 /air as an alternative to SF 6 gas

“…In [15] dry air, nitrogen and carbon dioxide were examined but analysis shows that these gases lesser withstood voltage and there was a significant increase in the size of equipment. In [12, 16–23] mixtures of or have been studied and investigation show that it has high boiling point and toxic for reproduction. Mixtures of with air and have been reviewed but research shows that it has high boiling point and high minimum operating temperature that for [14, 24].…”

Breakdown of CF3I gas and its mixtures under lightning impulse in coaxial-gil geometry

“…By-products analysis determined the generation of C 2 F 6 , C 2 F 4 , CHF 3 , C 3 F 8 , C 3 F 6 and C 3 F 5 I during the breakdown of CF 3 I gas. Electron swarm parameters [14][15][16] and arc extinguishing capabilities [17] for CF 3 I gas mixtures were also investigated through experiments.…”