架空地线间隙放电对线路零序阻抗的影响  

Study on Influence of Groundwire-involved Gap Flashover on Line Equivalent Zero-sequence Impedance

作　　者：吴伯华[1] 陈继东[1] 朱克[2] 

机构地区：[1]华中电网有限公司技术中心,武汉430077 [2]华中电网有限公司生产技术部,武汉430077

出　　处：《高电压技术》2006年第10期8-10,共3页High Voltage Engineering

摘　　要：针对≥220kV电压的架空地线多采用分段绝缘、一点接地方式运行,其地线绝缘子并联间隙在雷电先导和系统接地故障期间会击穿放电。放电后,因地线中零序感应电流构成回路流通,形成额外的去磁作用,使得架空地线和三相导线间的电磁耦合关系骤变,这会引起相应线路等值零序阻抗Z0幅值和相位的较大变化,进而可能导致线路接地距离保护的误动。进一步定性和定量地分析了这种变化,并将Z0计算值、设计值和现场实测值交互对照,明确提出Z0的上述变化一定条件下会引起线路继电保护的误动或拒动。It is our usual practice in China that the O/H groundwires of 220 kV＆ above transmission lines is seetionalized and insulated via special insulator, to which a shunt protective gap is attached. This gap will spark over ＆ disrupt when the lines subject to lightning strike or phase-to-earth faults according to design requirements. These leads up to the sudden decrease of the equivalent zero-sequence impedance Z0 due to the change of electrostatic ＆ electromagnetic couplings between phase lines and groundwires. This paper analyzes this phenomenon from both qualitative and quantitative sides, which is usually overlooked by domestic researchers or operating departments, and presents the mutual comparison results among the calculated, the designed data and relevant field-tested values. Furthermore, the paper points out that related power relaying may be subject to real-functioning or action-defeats under certain conditions in connection with the aforesaid sudden change.

关 键 词：绝缘地线 零序阻抗 继电保护 输电线路 并联间隙 接地故障 保护误动 

分 类 号：TM86[电气工程—高电压与绝缘技术] TM773