Abstract:C4F7N/CO2 mixture has the potential to replace SF6 gas in electrical equipment such as GIS or GIL as insulating dielectric. Its insulation performance is the basis for insulation design of electrical equipment. Electrical equipment can’t avoid to encounter different ambient temperatures in operation. It is necessary to study the insulation performance of C4F7N/CO2 mixture when temperature changes. The insulation properties of C4F7N/CO2 mixture at room temperature have been studied a lot, but seldom at different temperatures. In this paper, the influence of temperature on the critical discharge field intensity of C4F7N/CO2 gas mixture in the temperature range from -35~20℃ is studied. A calculation model of the critical discharge field intensity of C4F7N/CO2 mixture is established at different temperatures. In order to verify the calculation model, we did breakdown experiments at different temperatures. The power frequency discharge voltages at different temperatures are obtained for C4F7N/CO2 mixture at pressures 0.6MPa and 0.7MPa with 9% C4F7N. The liquefaction temperature of 9% C4F7N/CO2 mixture at 0.7MPa and 0.6MPa is about -19℃ and -23℃ respectively. The experimental results verify the validity of the calculation model. At the same time, it is found that after liquefaction, the power frequency discharge field intensity decreases significantly with the decrease of temperature. The critical discharge field intensity of C4F7N/CO2 mixture with different ratios at 0.6MPa and 0.7MPa is studied using the calculation model. The power frequency discharge field intensity of C4F7N/CO2 gas mixture at different mixing ratio and temperature is obtained.
郑宇, 周文俊, 喻剑辉, 李涵, 马晨曦. 温度对C4F7N/CO2混合气体工频放电场强的影响规律[J]. 电工技术学报, 2020, 35(1): 52-61.
Zheng Yu, Zhou Wenjun , Li Han, Ma Chenxi. Influence of Temperature on Power Frequency Discharge Field Intensity of C4F7N/CO2 Mixed Gas. Transactions of China Electrotechnical Society, 2020, 35(1): 52-61.
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