温度对C4F7N/CO2混合气体工频放电场强的影响规律  

Influence of Temperature on Power Frequency Discharge Field Intensity of C4F7N/CO2 Mixed Gas

作　　者：郑宇 周文俊[1] 喻剑辉[1] 李涵[1] 马晨曦 Zheng Yu;Zhou Wenjun;Yu Jianhui;Li Han;Ma Chenxi(School of Electrical Engineering and Automation Wuhan University,Wuhan 430072 China)

机构地区：[1]武汉大学电气与自动化学院

出　　处：《电工技术学报》2020年第1期52-61,共10页Transactions of China Electrotechnical Society

基　　金：国家重点研发计划（2017YFB0902500）;国家电网公司科技项目“环保型管道输电关键技术”资助项目

摘　　要：C4F7N/CO2混合气体有潜力替代SF6气体应用于气体绝缘全封闭组合电器(GIS)或环保气体绝缘管道(GIL)等电气设备中作为绝缘电介质,掌握其绝缘性能是进行电气设备绝缘设计的基础。电气设备在实际运行中会遇到不同的环境温度,有必要研究温度变化时C4F7N/CO2混合气体的绝缘性能。常温下C4F7N/CO2混合气体的绝缘性能已有较多研究,但鲜见不同温度下的研究。该文研究了-35~20℃温度范围内,温度对C4F7N/CO2混合气体的工频放电场强的影响规律,建立C4F7N/CO2混合气体的放电场强随温度变化的计算模型。为验证计算模型,开展不同温度下的工频放电试验,采用球板电极下的放电试验得到初始充气压力0.7MPa和0.6MPa下,混合比例9%C4F7N/91%CO2混合气体在不同温度下的工频放电电压,得到0.7MPa下混合比例为9%C4F7N/91%CO2混合气体的液化温度约为-19℃,0.6MPa下的液化温度约为-23℃,试验结果验证了计算模型的有效性。同时发现C4F7N/CO2混合气体在发生液化后,其工频放电场强随温度降低而显著降低。利用该文的计算模型研究0.6MPa和0.7MPa下不同混合比例的C4F7N/CO2混合气体的工频放电场强随温度的变化,获得了不同混合比例不同温度下C4F7N/CO2混合气体的工频放电场强。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.

关 键 词：SF6 替代气体 C4F7N/CO2混合气体 液化温度 气体放电 

分 类 号：TM85[电气工程—高电压与绝缘技术]