基于测量波阻抗的高压直流输电线路纵联保护  

Pilot Protection Based on Measured Surge Impedance for HVDC Transmission Lines

作　　者：李小鹏[1] 滕予非[1] 刘耀[2] 汤涌[2] 甄威[1] 

机构地区：[1]国网四川省电力公司电力科学研究院,四川省成都市610072 [2]中国电力科学研究院,北京市海淀区100192

出　　处：《电网技术》2017年第2期617-623,共7页Power System Technology

基　　金：中国博士后科学基金(2016M592659)~~

摘　　要：针对目前直流输电线路保护灵敏性和速动性难以兼顾的问题,提出一种基于测量波阻抗的直流线路保护方法。利用S变换提取单频率的电压、电流初始行波并计算线路两端的测量波阻抗。在线路内部故障时,线路两端测量波阻抗均为测点背侧等效阻抗,差异较小;在线路外部故障时,线路两端测量波阻抗分别为测点背侧等效阻抗和线路波阻抗,差异较大,据此可以区分直流线路上的内部和外部故障。基于PSCAD/EMTDC的大量仿真结果表明,该保护方法易于整定,在各种故障情况下均能可靠、快速地识别直流线路内部和外部故障。In order to solve the problem that present protections for HVDC transmission line hardly satisfy simultaneously requirement in sensitivity and speed, a novel pilot protection method based on measured surge impedance is proposed in this paper. Initial voltage and current traveling waves of single frequency are extracted with S transform and used to calculate measured surge impedance at two line terminals. When an internal fault occurs, measured surge impedances at two terminals are both backside equivalent impedances with small difference in amplitude. For external fault, one measured surge impedance is backside equivalent impedance and the other is line surge impedance, and their amplitude difference is relatively large. Thus, external faults and internal faults can be distinguished by amplitude difference between the measured surge impedances. Large amount of simulation results based on PSCAD/EMTDC indicate that the proposed protection method can be easily set and discriminate internal faults from external under various fault conditions.

关 键 词：直流输电线路 S变换 测量波阻抗 纵联保护 高阻故障 

分 类 号：TM72[电气工程—电力系统及自动化]