Investigation of insulation properties and synergistic effects in CF3I/N2 gas mixtures using the Boltzmann equation

CF3I is regarded as a highly promising substitute for SF6; however, due to its high boiling point, buffer gases such as N2 must be blended. To evaluate the feasibility of replacing SF6 and its mixtures with CF3I/N2, a comparative analysis was conducted. This evaluation concentrated on the electron energy distribution, reaction coefficients, insulation performance, and synergistic effects of CF3I/N2 and SF6/N2 mixtures at various ratios. Within the range of 200–400 Td, the variation rate of electron energy distribution in CF3I/N2 mixtures is lower than that in SF6/N2 mixtures. CF3I/N2 mixtures show a more uniform and linear increase in insulation strength with the CF3I ratio compared to SF6/N2. At a 65%/35% ratio, the insulation strength of CF3I/N2 compares well to that of SF6/N2; below this ratio, CF3I/N2 displays a lower insulation strength, whereas it shows a higher strength above this ratio. When the CF3I/N2 ratio reaches 70%/30%, the insulation strength exceeds that of pure SF6. Regarding synergistic effects, both mixtures reach maxima near a 10%/90% ratio; however, SF6/N2 consistently exhibits a higher synergistic effect coefficient than CF3I/N2.