Electron Swarm Parameters in $\hbox{c-C}_{4} \hbox{F}_{8}$ and $\hbox{CO}_{2}$ Gas Mixtures From Boltzmann Equation Analysis

The electron swarm parameters in c-C 4 F 8 /CO 2 gas mixtures, including the density-normalized effective ionization coefficient (α-η)/ N and the drift velocity V e , are calculated for the overall density-reduced electric-field strength E / N values from 150 to 600 Td (1 Td = 10 -17 V · cm 2 ). These calculations have been performed through solving the Boltzmann equation under the two-term approximation in the condition of steady-state Townsend experiment. The c-C 4 F 8 content k in the gas mixtures can be varied over the range of 0%-100 %. From the variation curve of (α-η)/ N with the c-C 4 F 8 mixture ratio k , the limiting field strength ( E / N ) lim for each c-C 4 F 8 concentration is determined for the analysis of the insulation characteristics of the c-C 4 F 8 /CO 2 mixture. Additionally, the global-warming potential and the liquefaction temperature of c-C 4 F 8 /CO 2 gas mixtures are also taken into account to evaluate the possibility of applying in gas insulation of power equipment.