基于电压和电流突变量的高压直流输电线路保护原理  

Protection Principle for HVDC Transmission Lines Based on Fault Component of Voltage and Current

作　　者：邢鲁华[1] 陈青[1] 付兆远[1] 高湛军[1] 于春光[1] 

机构地区：[1]山东大学电气工程学院,山东省济南市250061

出　　处：《电力系统自动化》2012年第9期61-66,共6页Automation of Electric Power Systems

基　　金：国家电网公司科技项目(5250909)~~

摘　　要：在对高压直流输电线路区内、外故障和雷击等暂态过程研究的基础上,提出了一种基于电压、电流突变量变化特征的高压直流输电线路主保护原理。该原理对两极线路同侧保护安装处测得的电压突变量幅值的比值设定阈值,选出故障极;利用故障线路两端电流突变量的极性在线路保护区内故障时相异、在区外故障时相同,区分线路上保护区内和区外故障。PSCAD/EMTDC软件对实际高压直流输电系统的仿真结果表明,该保护原理在双极两端中性点接地方式下能够快速判别故障极和区分线路上保护区内、外故障,可靠排除雷击干扰,在故障性雷击和高阻抗接地时准确动作,并适用于一极降压和一极全压运行、功率反送、一极停电检修及单极金属回线运行方式等。采样频率在10～100kHz范围内时可满足保护判据计算要求。A new main protection principle is presented for high voltage direct current（HVDC） transmission lines.The principle is based on the variation characteristics of fault component of voltage and current,together with an indepth research on the transients caused by internal faults,external faults and lightning disturbances.By a set threshold for the ratio of amplitudes of the fault components of voltage at the same side relay location on bipolar lines,faults outside HVDC lines can be excluded,and the fault line can be distinguished.The polarities of the fault component of currents at the ends of the fault line are different for internal faults,while are the same for external faults.Accordingly,internal faults and external faults can be distinguished.Simulation results based on PSCAD/EMTDC for a practical HVDC transmission system demonstrate that the fault line can be rapidly selected and internal faults and external faults can be distinguished by the protection under bipolar neutral grounding at both ends mode.Lightning disturbances can be excluded by the proposed criterion.The protection criterion can move accurately for faults with high transition resistance and lightning induced faults,and can be also applied under one pole with 70% voltage and one pole with total voltage operation mode,anti-way power delivery operation mode,monopolar metallic return operation mode and one pole with maintenance outage.The calculation requirement of the protection criterion can be satisfied with sampling frequency in the range of 10～100 kHz.

关 键 词：线路保护 高压直流输电 电压突变量 电流突变量 雷击 小波变换 

分 类 号：TM773[电气工程—电力系统及自动化]