摘要
直流气体绝缘金属封闭输电线路（gas insulated transmission line,GIL）在一些特殊环境下可替代部分架空输电线路或电缆提高输电走廊选择的灵活性。影响直流GIL中绝缘子水平的关键因素有氧化铝填料比例、自由导电微粒等。该文对SF6气体中,负极性直流电压下不同氧化铝含量（250～400 phr）的环氧绝缘子在准均匀场和极不均匀场下的沿面绝缘特性和烧蚀特性进行了研究。结果表明,准均匀场情况下,填料含量250 phr的绝缘子在短时闪络特性和长时耐压特性方面都具有最好的沿面电气强度,同时在极不均匀场中也具有最好的沿面电气性能。而填料含量为350 phr的绝缘子则具有最差的直流耐压特性以及耐烧蚀特性。通过对闪络微观图像的分析,可知闪络过程发生在绝缘子的浅表面。同时,通过分析电树枝发展图像的分形维数,发现了填料含量对环氧绝缘子闪络烧蚀特性以及直流电压下的绝缘子电树枝发展特性的影响。
DC gas insulated transmission line（GIL） can be utilized to substitute part of the overhead lines or cables in special environments to improve the flexibility of the selection of the transmission corridor. Key factors that greatly threaten the insulation level of DC GIL include free conducting particles and contents of alumina filler. Influence of the content of alumina filler on the characteristics of flashover and erosion of the alumina filled cast epoxy resin insulator in quasi-uniform field and highly non-uniform field in SF6 gas under negative DC voltage was investigated. Results show that among alumina filled epoxy resin insulators with filler contents from 250 phr to 400 phr, insulator with filler content of 250 phr has most excellent surface dielectric strength than those of other insulators in both short-term flashover and long-term withstand voltage tests, as well as the best erosion property in both the quasi-uniform field and highly non-uniform field. While the insulator with filler content of 350 phr has the worst performance. The flashover takes place in the shallow surface of the insulator according to its microscopic image of the flashover trace. Meanwhile, influence of the filler content on the erosion characteristics of the flashover and the tree properties under DC voltage were studied by analyzing the fractal dimension of tree trace of the flashover.
出处
《中国电机工程学报》
EI
CSCD
北大核心
2014年第36期6523-6529,共7页
Proceedings of the CSEE
基金
国家电网公司科技项目资助项目(SGAH0000 KXJS1401753)~~
