应用于直流GIL中低混合比c-C4F8/N2混合气体的绝缘特性  

Insulation Characteristics of c-C4F8/N2 with Less c-C4F8 Applied to HVDC-GIL

作　　者：张然[1,2] 王珏[1,2] 严萍[1,2] ZHANG Ran;WANG Jue;YAN Ping(Institute of Electrical Engineering,Chinese Academy of Sciences,Beijing 100190,China;Key Laboratory of Power Electronics and Electric Drive,Chinese Academy of Sciences,Beijing 100190,China)

机构地区：[1]中国科学院电工研究所,北京100190 [2]中国科学院电力电子与电气驱动重点实验室,北京100190

出　　处：《高电压技术》2018年第8期2672-2678,共7页High Voltage Engineering

基　　金：国家重点基础研究发展计划(973计划)(2014CB239502-2)~~

摘　　要：目前GIL中使用的气体绝缘介质均为SF6气体。SF6气体虽然具有优异的电气性能,但是全球变暖潜能值（GWP）极高,因此迫切需要找到能够替代SF6的绝缘气体。文中以混合比k（c-C4F8在混合气体中的体积分数）低于20%的c-C4F8/N2混合气体为主要研究对象,通过调节气压（0.1～0.65 MPa）和气隙间距（1～7 mm）测量了不同混合比k下混合气体的击穿电压和闪络电压,并与纯SF6气体的击穿电压和闪络电压进行了对比分析。试验结果表明：c-C4F8与N2呈协同效应关系;k=20%时,混合气体绝缘击穿强度约为纯SF6气体的0.6倍,绝缘闪络强度约为纯SF6气体的0.7倍,2 h耐受电压比短时闪络电压降低了5%～10%;通过提高c-C4F8/N2混合气体的气体压强或增大绝缘距离可以实现替代SF6的目的。考虑到c-C4F8在放电中的碳析出问题,应避免混合气体用于频繁放电的设备中。Insulating gas SF6 has been used in gas insulated line（GIL） due to its excellent electrical capabilities. However, it is urgently required to find a gas to substitute SF6 due to its high global warming potential（GWP）. Consequently, we studied c-C4F8/N2 mixture gas with gas ratio lower than 20% as the main object. The DC breakdown voltage and flashover voltage of c-C4F8/N2 mixture gas with different gas ratio k were measured in different gas pressures（0.1～0.65 MPa） and gap distance（1～7 mm） and then compared with that of pure SF6. The results show that the c-C4F8/N2 mixture gas presents a synergistic effect. The breakdown strength of mixture gas with 20% c-C4F8 is about 0.6 times that of pure SF6 and the flashover strength is about 0.7 times. The two-hour withstand voltage is 5%～10% lower than the flashover voltage. There is a possibility that the c-C4F8/N2 mixed gas can be used for substituting SF6, with increasing the gas pressure or insulation dimension. Because the carbon granule is one components of decomposition products for discharged c-C4F8 gas, the application of the c-C4F8/N2 mixture gas in frequent discharge devices should be avoided.

关 键 词：高压直流 气体绝缘传输线 SF6 c-C4F8 直流击穿 闪络 协同效应 

分 类 号：TM21[一般工业技术—材料科学与工程]