Discharge Characteristics of 252kV Gas Insulated Transmission Line under Switching Impulse Voltage in C4F7N/CO2 Mixtures
Zheng Zhongbo1, Chen Nan2, Li Zhichuang1, Li Qiang2, Ding Weidong1
1. State Key Laboratory of Electrical Insulation and Power Equipment Xi’an Jiaotong University Xi’an 710049 China; 2. Xi’an High Apparatus Research Institute Co. Ltd Xi’an 710077 China
Abstract：C4F7N/CO2 mixed gas has been widely studied as an environmentally friendly insulating gas that is expected to replace SF6 in high-voltage gas insulated transmission line (GIL). In high-voltage power systems, the dielectric characteristics of the medium under switching impulse have become an important factor. However, there are few studies on gap breakdown and flashover characteristics of C4F7N/CO2 mixtures under switching impulse voltage. This paper studies the gap breakdown and flashover characteristics of 252kV GIL in C4F7N/CO2 mixtures with C4F7N content of 5%, 9%, and 13%, and compares them with the experimental results in 0.5MPa SF6. The results show that the discharge voltage increases with the increase of the gas pressure and the content of C4F7N. There are two forms of discharge. One is gap-surface flashover and the other is gap breakdown. The electrical insulation strength under 0.5MPa 13% C4F7N/87% CO2 and 0.6MPa 9% C4F7N/91% CO2 mixtures reaches over 87% of the electrical insulation strength under SF6 at 0.5MPa, and the electrical insulation strength under 0.7MPa 9% C4F7N/91% CO2 exceeds the insulation strength of SF6 at 0.5MPa.
郑忠波, 陈楠, 李志闯, 李强, 丁卫东. 操作冲击电压下C4F7N/CO2混合气体252kV GIL间隙及沿面放电特性[J]. 电工技术学报, 2021, 36(14): 3055-3062.
Zheng Zhongbo, Chen Nan, Li Zhichuang, Li Qiang, Ding Weidong. Discharge Characteristics of 252kV Gas Insulated Transmission Line under Switching Impulse Voltage in C4F7N/CO2 Mixtures. Transactions of China Electrotechnical Society, 2021, 36(14): 3055-3062.
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2021, Vol. 36 
