Ageing of C4F7N and CO2-based insulating gas mixtures by free-burning arcs

Authors

  • A. Subhana Department of Electric Energy, Norwegian University of Science and Technology, Trondheim, 7491, Norway
  • N. Støa-Aanensen SINTEF Energy Research, Trondheim, 7491, Norway
  • F. Mauseth Department of Electric Energy, Norwegian University of Science and Technology, Trondheim, 7491, Norway

DOI:

https://doi.org/10.14311/ppt.2025.3.219

Keywords:

SF6 alternative gases, arc contact erosion, arc voltage, gas decomposition, ageing

Abstract

This study examines the effects of arc-induced ageing in CO2/O2 (86.3%/13.7%),
C4F7N/CO2/O2 (5%/82%/13%) and C4F7N/CO2 (5%/95%) mixtures at 5 bar absolute pressure. The gases were subjected to a series of free-burning arcs with a total energy dissipation relevant to high-voltage circuit breaker applications. The arc voltage remained similar across all mixtures with no significant variation due to ageing or the addition of C4F7N and O2. In addition, the influence of the insulating gas on the erosion of the arcing contacts (20% wt. Cu/80% wt. W) was analyzed. While the increase in average surface roughness was comparable across all mixtures, the contact mass loss was relatively higher in those containing C4F7N. Decomposition of the gas mixtures was examined through gas chromatography-mass spectrometry analyses. Solid byproducts generated during arcing were analyzed using scanning electron microscopy (SEM) coupled with energy-dispersive X-ray spectroscopy (EDS).

References

W. Wang, X. Yan, H. Wang, and K. Gao. Comparative studies of C4F7N-based gas mixtures as the eco-friendly alternative to SF6 for interrupting applications. High Voltage, 2025. doi:10.1049/hve2.70003.

J. Y. Na, R. Hwang, S. J. Cho, et al. Breakdown characteristics of a fluoronitrile mixture gas according to mixing ratio and oxygen content for high-voltage power equipment application. IEEE Access, 12:16117–16126, 2024. doi:10.1109/ACCESS.2024.3359304.

B. Zhang, N. Uzelac, and Y. Cao. Fluoronitrile/CO2 mixture as an eco-friendly alternative to SF6 for medium voltage switchgears. IEEE Transactions on Dielectrics and Electrical Insulation, 25(4):1340–1350, 2018. doi:10.1109/TDEI.2018.007146.

B. Zhang, R. Zhou, K. Wang, et al. Arc interruption performance of C4F7N-CO2 mixture in a 126 kV disconnector. IEEE Transactions on Power Delivery, 38(2):1197–1207, 2022. doi:10.1109/TPWRD.2022.3210381.

P. Pietrzak, J. T. Engelbrecht, P. Simka, et al. Voltage–current characteristic of free burning arcs in SF6 alternative gas mixtures. IEEE Transactions on Plasma Science, 50(11):4744–4752, 2022. doi:10.1109/TPS.2022.3210995.

W. Wang, K. Gao, X. Yan, et al. Numerical study of the arc-quenching performance of eco-friendly C4F7N/CO2/O2 gas mixtures. Journal of Physics D: Applied Physics, 58(18):185207, 2025. doi:10.1088/1361-6463/adc60c.

P. Pietrzak, M. Perret, M. Boening, et al. Wear of the arcing contacts and gas under free burning arc in SF6 alternatives. IEEE Transactions on Power Delivery, 38(3):2133–2140, 2023. doi:10.1109/TPWRD.2023.3234364.

G. Qi, F. Yuan, Y. Zheng, et al. Research on the aging judgment method of electrical performance of C4F7N/CO2 mixed gases. In Journal of Physics: Conference Series, volume 2774, page 012061. IOP Publishing, 2024. doi:10.1088/1742-6596/2774/1/012061.

Y. Zhou, J. E. Humphries, J. W. Spencer, et al. Contact erosion at high currents in high-voltage gas circuit breakers—part I: Experimental research and material testing. IEEE Transactions on Power Delivery, 2024. doi:10.1109/TPWRD.2024.3520027.

Y. Zhou, J. E. Humphries, J. W. Spencer, et al. Contact erosion at high currents in high-voltage gas circuit breakers—part II: Assessment of energy balance of arc-electrode. IEEE Transactions on Power Delivery, 2024. doi:10.1109/TPWRD.2024.3519952.

Y. Zhou, J. E. Humphries, J. W. Spencer, et al. Contact erosion induced by free-burning arcs in an experimental gas circuit breaker. IEEE Transactions on Power Delivery, 2025. doi:10.1109/TPWRD.2025.3543855.

A. Subhana, N. S. Støa-Aanensen, M. Gammelsæter, and F. Mauseth. Laboratory setup for ageing of new environmentally friendly insulation gases. In Proceedings of the 23rd International Conference on Gas Discharges and their Applications, pages 358–361, 2023.

A. Subhana, N. S. Støa-Aanensen, M. Gammelsæter, et al. Ageing of technical air and technical air with 7.5% C5-Fluoroketone by free-burning arcs. Plasma Physics and Technology, 10(2):89–93, 2023. doi:10.14311/ppt.2023.2.89.

B. Zhang, C. Li, J. Xiong, et al. Decomposition characteristics of C4F7N/CO2 mixture under AC discharge breakdown. AIP Advances, 9(11), 2019. doi:10.1063/1.5115588.

K. Niayesh and M. Runde. Power Switching Components: Theory, Applications and Future Trends. Power Systems. Springer, 2017. ISBN 978-3-319-51460-4. URL: https://link.springer.com/book/10.1007/978-3-319-51460-4.

Y. Luo, W. Wang, R. Zhuo, et al. Current interruption characteristics of C4F7N/CO2 mixture in a load switch. In 2020 IEEE International Conference on High Voltage Engineering and Application (ICHVE), pages 1–4. IEEE, 2020. doi:10.1109/ICHVE49031.2020.9279898.

P. Pietrzak, J. T. Engelbrecht, D. Kumari, and C. M. Franck. Short-line fault interruption performance comparison of SF6 alternatives. IEEE Transactions on Power Delivery, 2024. doi:10.1109/TPWRD.2024.3451178.

W. E. Coleman, L. D. S. Ph.D., R. E. Kupel, and R. L. Larkin. The identification of toxic compounds in the pyrolysis products of polytetrafluoroethylene (PTFE). American Industrial Hygiene Association Journal, 29(1):33–40, 1968. doi:10.1080/00028896809342978.

D. Guo, X. Li, W. Wang, and Z. Geng. Effect of the arc extinguishing and insulation properties of C4F7N/CO2 mixtures with oxygen addition: Experimental investigations and comparative analysis. Energies, 17(17):4202, 2024. doi:10.3390/en17174202.

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Published

2025-12-30

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