Insulation Characteristics of C3F8 Ternary Gas Mixtures from Electron Transport Parameters and Microscopic Properties

In order to study an alternative SF
₆
gas medium, molecular theory and density functional theory (DFT) were used to analyze C
₃
F
₈
as a substitute for SF
₆
gas from microscopic properties. This paper aimed to adopt the Boltzmann equation method to calculation the electron transport coefficients and synergistic effect of C
₃
F
₈
/CF
₃
I/CO
₂
ternary gas mixtures, and compared with c-C
₄
F
₈
/CF
₃
I/CO
₂
of same proportion. The results indicate that when E/N is lower than 400Td, the performance of C
₃
F
₈
gas mixtures is better than that of c-C
₃
F
₈
gas mixtures in terms of diffusion coefficient and electron drift velocity. When the proportion of C
₃
F
₈
is less than 7%, the insulation strength of gas mixtures is higher than that of 30%SF6 /70%CO
₂
gas mixtures. As for synergistic effect, for C
₃
Fs/CF
₃
I/CO
₂
is most obvious when the content of C
₃
F
₈
is about 10%. The research results in this paper provide a theoretical basis for C
₃
F
₈
ternary gas mixtures as a potential replacement gas for SF
₆
.