基于突变电流积聚量的高压直流输电线路伪同步差动保护新原理  

Principle of Pseudo-synchronous Differential Protection Based on Sudden Current Accumulation for HVDC Transmission Lines

作　　者：曹虹 周泽昕 柳焕章 张志 王兴国 杜丁香 李勇 金明亮 CAO Hong;ZHOU Zexin;LIU Huanzhang;ZHANG Zhi;WANG Xingguo;DU Dingxiang;LI Yong;JIN Mingliang(State Key Laboratory of Power Grid Safety and Energy Conservation(China Electric Power Research Institute),Haidian District,Beijing 100192,China;Central China Branch of State Grid Corporation of China,Wuhan 430077,Hubei Province,China;State Grid Corporation of China,Xicheng District,Beijing 100032,China)

机构地区：[1]电网安全与节能国家重点实验室(中国电力科学研究院有限公司),北京市海淀区100192 [2]国家电网有限公司华中分部,湖北省武汉市430077 [3]国家电网有限公司,北京市西城区100032

出　　处：《电网技术》2022年第1期70-80,共11页Power System Technology

基　　金：国家电网有限公司科技项目(5100-202055016A-0-0-00):“基于故障暂态电流的高性能直流输电线路保护技术研究”。

摘　　要：为解决现有高压直流线路电流差动保护动作延时长(秒级)的问题,提出基于突变电流积聚量的伪同步差动保护新原理。分析两端电流在区内外故障时的突变特征,提出突变电流积聚量以有效捕捉电流突变方向,利用两端突变电流积聚量分别构造动作电流和制动电流,提出全新原理的直流差动保护,并通过伪同步算法进一步缩短保护动作时间。此外,比较两端电流数据在伪同步和同步算法下的时序关系,进一步分析伪同步算法的优越性。仿真验证结果表明,保护新原理具有高快速性和灵敏性,考虑20ms线路通道延时,区内金属性故障时保护的动作时间不大于20ms,经高阻故障(高达800Ω)时保护动作时间不大于27.6ms。保护新原理不需对分布电容电流进行补偿,两端数据不需完全同步,算法计算量小且对数据采样率没有高要求,工程实用性强。In order to solve the problem that it needs a long time(usu. second level) for the HVDC transmission line traditional current differential protection to operate, a new principle of pseudo-synchronous differential protection based on the sudden current accumulation for the HVDC transmission lines is presented in this paper. By analyzing the characteristics of the current sudden changes at both sides under the internal and external fault conditions, the sudden current accumulation is proposed to effectively identify the directions of the current sudden changes. By constructing the action current and the braking current with the sudden current accumulations at both sides, the novel principle of DC differential protection is proposed and the pseudosynchronization algorithm is put forward to further shorten the protection operation time. In addition, comparing the timing relationships between the current data at both sides under the pseudo-synchronization and the synchronization algorithms,the superiority of the pseudo-synchronization algorithm is further analyzed. The RTDS simulation results show that the new protection proposed has higher speed and sensitivity.Considering the channel delay with 20 ms, the protection operation time is not more than 20 ms when an internal ground fault occurs, and it is not more than 27.6 ms when an internal fault with high resistance(up to 800Ω) occurs. No compensation of the distributed capacitor current and no precise data synchronization at the two ends needed, the algorithm requires a small calculation and a lower data sampling rate, which is strongly practicable in engineering.

关 键 词：高压直流输电线路 突变电流积聚量 电流差动保护 伪同步 

分 类 号：TM721[电气工程—电力系统及自动化]