基于纵联阻抗幅值的输电线路纵联保护  

A transmission line pilot protection based on the amplitude of the pilot impedance

作　　者：夏经德[1] 索南加乐[1] 王莉[1] 何世恩[1] 刘凯[1] 邓旭阳[1] 

机构地区：[1]西安交通大学电气工程学院,陕西西安710049

出　　处：《电力系统保护与控制》2011年第4期43-51,共9页Power System Protection and Control

基　　金：国家自然科学基金项目(50677051;50877061);高等学校博士学科点专项科研基金项目(20070698057)~~

摘　　要：提出了一种基于纵联阻抗幅值的输电线路纵联保护。该纵联阻抗是由线路两端各相电压故障分量差与电流故障分量和的比值计算而来的,利用这个阻抗的幅值判断故障是否发生在区内。区外故障时,上述阻抗的幅值明显大于全线串联正序阻抗的幅值;区内故障时,该阻抗的幅值明显小于上述定值。该保护不仅易整定、具有自选相功能,性能稳定、动作灵敏、适应性强,而且能有效抵御由线路电容电流和CT饱和所带来的影响。在EMTP数字仿真和动模试验中,建立一条1000kV、500km和一条500kV 50km输电线路的模型,后者还考虑了CT饱和,使用兰州东至咸阳750kV的动模数据,进行了各种故障下仿真,结果表明所述纵联保护都能正确标示各种故障状态。A pilot protection of transmission line based on the amplitude of the pilot impedance is proposed.The pilot impedance is computed by using the ratio of the difference of the fault-superimposed components of voltage to the summation of the fault-superimposed component of current at each phase of the both terminals of the line,and according to the amplitude of this impedance,whether the fault occurres at the line can be judged.When the fault occurres outside of the protected zone,the amplitude of the aforesaid impedance is significantly greater than the amplitude of series positive sequence impedance of the fully line,while it is obviously smaller than the determined value when the fault occurred inside of the protected zone.The proposed pilot protection not only has the characteristics of easy protective coordination,independent phase selection,stable function,sensitive operation and strong adaptation,but also possesses identity of the effective resistance of the influence brought by the line capacitor current and CT saturation.In EMTP simulation and the dynamic model experiment,the transmission line models of a 1000 kV 500 km and a 500 kV 50 km are established, and the latter considers CT saturation,uses the dynamic model data of Lanzhou-Xianyang 750 kV line, and executes the simulations under each fault.The simulation results indicate that the mentioned pilot pretection can all correctly mark each fault state.

关 键 词：输电线路 故障分量 纵联保护 两端电气量 纵联阻抗 阻抗幅值 

分 类 号：TM773[电气工程—电力系统及自动化]