Measurement of Ionization and Attachment Coefficients in C4F7N/CO2 Gas Mixture as Substitute Gas to SF6

Autor: Yunxiang Long, Liping Guo, Cheng Chen, Zhenyu Shen, Yiheng Chen, Fang Li, Wenjun Zhou
Jazyk: angličtina
Rok vydání: 2020
Předmět:
Zdroj: IEEE Access, Vol 8, Pp 76790-76795 (2020)
Druh dokumentu: article
ISSN: 2169-3536
DOI: 10.1109/ACCESS.2020.2990301
Popis: As one of the alternative insulation gases, C4F7N/CO2 gas mixtures have attracted much attention recently. In this study, the normalized Townsend first ionization coefficient α/N and the normalized attachment coefficient η/N were measured in C4F7N/CO2 gas mixtures by using the Steady-State Townsend (SST) method over a range of electric fields E/N from 100 to 550 Td. The concentrations of C4F7N studied were 4.99, 7.00, 9.00, 13.13 and 20.02%, and the gas pressure were 500 Pa at 20°C. The effective ionization coefficients and the critical electric field were obtained at 500, 1000 and 2000 Pa to investigate the effect of gas pressure on dielectric strength in 9.00%C4F7N/91.00%CO2 respectively. The results indicated that the (E/N)lim have not significant change on the SST experimental conditions. Meanwhile, a comparison with SF6 gas indicates that 20.02% C4F7N/79.98% CO2 has a similar insulation performance with (E/N)lim as 358.82 Td. However, when the liquefaction temperature is considered, the C4F7N/CO2 gas mixtures with 9.00% C4F7N could be considered as an appropriate substitute gas for SF6, because the critical electric field of this gas mixture is over 70% of SF6 gas and could be used under -15°C at 0.7 MPa.
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