摘要
目前在电力行业中广泛应用的SF6气体具有严重的温室效应,寻找一种绝缘性能优良的环保型替代气体成为研究热点。近年来,C3F7CN及其混合气体凭借出色的绝缘性能和环保特性得到了国内外学者的广泛关注。目前针对其放电分解机理的研究较少。首先,基于ReaxFF反应分子动力学方法和密度泛函理论,从微观层面模拟研究了C3F7CN/CO2混合气体的分解机理。基于构建的C3F7CN/CO2混合气体模型,研究了温度对C3F7CN分解过程的影响,分析了其可能的分解路径、产物类型及分布等。计算结果表明,C3F7CN在局部过热或放电等故障条件下分解容易产生CF3·、C3F7·、C·、CF3CFCN·、CF2·和F·等各类自由基,上述自由基复合将产生CF4、C2F6、C3F8、CF3CN、CO等产物。其次,利用气体绝缘试验平台和气相色谱质谱联用仪(gas chromatography mass spectrometer,GC-MS),试验分析了其多次击穿后的分解产物。试验结果表明,混合气体多次击穿后的主要分解产物是CF4、C2F6、CF3CN。这些产物分子均具有比较好的绝缘能力,保障了C3F7CN/CO2混合气体的绝缘性能不被破环。相关结论为进一步探究C3F7CN/CO2混合气体的绝缘特性及协同效应等课题提供理论依据和工程指导。
Due to the serious greenhouse effect of SF6 gas,which is currently widely used in the electrical power industry,it has become a common view that an environmental-friendly alternative candidate of excellent insulation performance should be found to replace SF6.Recently,the C3F7CN and its mixture,which have a low global warming potential(GWP)and excellent insulation properties,have attracted wide attention from domestic and foreign scholars.There are few studies on its decomposition mechanism under discharge.In this paper,firstly based on the molecular dynamics method and the ReaxFF force field and the density functional theory,the decomposition mechanism of C3F7CN/CO2 gas mixture was simulated from the micro level.Based on the constructed C3F7CN/CO2 models,the effect of temperature on the decomposition process of C3F7CN was studied,and the possible decomposition paths,product types and distributions were analyzed.The results show that the decomposition of C3F7CN can easily generate various kinds of free radicals such as CF3·,C3F7·,C·,CF3CFCN·,CF2,F· and so on under the conditions of local overheating or discharge,and further reactive combination of these free radicals will generate products such as CF4,C2F6,C3F8,CF3CN,CO and so on.Then,based on the gas insulation test platform and the gas chromatography mass spectrometer(GC-MS),the products after multiple breakdowns were analyzed.The test results show that the decomposition product are mainly CF4,C2F6,CF3CN.These molecules products have good insulation ability,which insure the insulation performance of C3F7CN/CO2 gas mixture.The conclusions provide theoretical basis for further research of insulation properties and synergistic effect of C3F7CN/CO2 gas mixture,and guide its practical engineering application.
作者
张晓星
陈琪
李祎
肖淞
张季
刘畅
ZHANG Xiaoxing;CHEN Qi;LI Yi;XIAO Song;ZHANG Ji;LIU Chang(School of Electrical Engineering and Automation,Wuhan University,Wuhan 430072,Hubei Province,China)
出处
《中国电机工程学报》
EI
CSCD
北大核心
2018年第24期7174-7182,共9页
Proceedings of the CSEE
基金
中国南方电网有限责任公司科技项目(ZBKJXM20170090)~~
作者简介
张晓星(1972),男,博士,教授,博士生导师,主要从事电气设备在线监测与故障诊断、绝缘状态评估和新型传感器技术的研究工作,xiaoxing.zhang@outlook.com。
