Sensitivity of C4F7N/CO2 Gas Mixture to Partial Inhomogeneous Electric Field
Yan Xianglian1, Zheng Yu2, Huang He1, Yang Yuan1, Zhou Wenjun2, Bai changyu3
1. China Electric Power Research Institute Beijing 100192 China;
2. School of Electrical Engineering and Automation Wuhan University Wuhan 430072 China;
3. Pinggao Group Co. Ltd Pingdingshan 467001 China
The discharge characteristics of electron-attaching gases are sensitive to non-uniform electric field. However, it is difficult to make the electrode surface completely smooth in high-voltage electrical equipment. The effect of surface roughness of electrodes is prominent when the pressure is high, thus reducing the gas insulation performance. C4F7N/CO2 gas mixture is a potential alternative gas to SF6. It is necessary to investigate the sensitivity of C4F7N/CO2 to inhomogeneous electric field distribution. In this paper, the local electric field distortion caused by rough electrode surface is analyzed theoretically, and the influence of electric field distortion on the insulation performance of C4F7N/CO2 is calculated. The figure of merit is proposed to evaluate the tolerance of C4F7N/CO2 gas mixture to inhomogeneous electric field. Compared with SF6, when the content of C4F7N is less than 20%, the figure of merit of C4F7N/CO2 mixture is higher than that of SF6, which increases with the content of C4F7N decreasing. In order to verify the calculation results, a rough electrode discharge model was developed. The discharge tests of C4F7N/CO2 and SF6 gases were carried out. The figures of merit of C4F7N/CO2 with 10% C4F7N content and SF6 gases were obtained, which were close to the calculation results. Based on the figures of merit of C4F7N/CO2 gas mixture, and considering the controlling requirement of electrode surface roughness in C4F7N/CO2 gas mixture equipment with the same insulation performance as that of SF6, it shows that as the content of C4F7N is in the range of 4%~20%, the controlling requirement of electrode surface roughness of 6.3μm in SF6 equipment is suitable for the design of C4F7N/CO2 equipment.
颜湘莲, 郑宇, 黄河, 杨圆, 周文俊, 柏长宇. C4F7N/CO2混合气体对局部不均匀电场的敏感特性[J]. 电工技术学报, 2020, 35(1): 43-51.
Yan Xianglian, Zheng Yu, Huang He, Yang Yuan, Zhou Wenjun, Bai changyu. Sensitivity of C4F7N/CO2 Gas Mixture to Partial Inhomogeneous Electric Field. Transactions of China Electrotechnical Society, 2020, 35(1): 43-51.
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2020, Vol. 35 
