直流气体绝缘金属封闭输电线路中绝缘子的表面电荷积聚研究  

Study of Charge Accumulation Along the Insulator Surface in the DC GIL

作　　者：贾志杰[1] 张斌[1] 范建斌[2] 李金忠[2] 李鹏[2] 张乔根[1] 

机构地区：[1]西安交通大学电气工程学院,陕西省西安市710049 [2]中国电力科学研究院,北京市海淀区100192

出　　处：《中国电机工程学报》2010年第4期112-117,共6页Proceedings of the CSEE

基　　金：国家自然科学基金项目(50877073)~~

摘　　要：直流气体绝缘金属封闭输电线路(gas insulated transmission line,GIL)在特殊环境下可替代部分架空输电线路或电缆,从而提高输电走廊选择的灵活性。严重影响直流GIL绝缘水平的关键因素之一是沿支撑绝缘子表面的电荷积聚现象。通过建立一个板板电极系统来模拟GIL中同轴圆柱结构的电场分布,研究直流下GIL中绝缘子电荷积聚的机制,绝缘子的形状、SF6的电导率对表面电荷积聚的影响,以及电荷积聚对绝缘子沿面电场分布的影响。结果表明,聚四氟乙烯绝缘子的表面电导率比体积电导率受电场的影响更大;初始时沿面法向场强小的绝缘子的电荷积聚能得到明显抑制;SF6的电导率与绝缘子表面电导率的比值影响积聚电荷的极性。In order to promote the flexibility of the selection of transmission corridors, the DC gas insulated transmission line （GIL） can be utilized to substitute parts of the overhead line or cable in some special environments. One of the key factors that greatly threaten the insulation level of the DC GIL was the accumulation of surface charges along the supporting insulators. The plane-plane electrode system was established to simulate the electric field distribution of the coaxial cylinder configuration in the GIL. The electric charging mechanism of insulators in the DC GIL, as well as the influence of the insulator＇s geometry and conductivity of SF6 gas on surface charge accumulation, was investigated. Results show that surface conductivity of the insulator made of PTFE is influenced more greatly than volume conductivity by the electric field. Charge accumulation can be significantly checked when the normal component of the initial field strength along the insulator＇s surface is small. The polarity of accumulated charges is influenced by the ratio of the gas conductivity and the surface conductivity of insulators.

关 键 词：表面电荷积聚 充电时间常数 体积电导率 表面电导率 电场强度 绝缘子形状 

分 类 号：TM85[电气工程—高电压与绝缘技术]