基于故障行波过程的直流线路单端保护

摘要

This paper analyzes travelling wave process of internal and external faults of DC transmission lines and presents single-end protection principle based on fault travelling wave process by using initial and subsequent travelling wave compo-nents in the fault process. It uses wavelet transformation for multi-resolution analysis which is able to effectively extract characteristics of internal and external fault travelling wave. On the basis of PSCAD/EMTDC,simulating verification is car-ried out for the protection algorithm. Results indicate that this principle can correctly distinguish internal and external faults of DC lines and identify high resistance grounding faults. It can remedy the defect of low sensitivity of the existing principle under high resistance grounding faults.%分析了直流线路区内和区外故障的行波过程，利用故障过程中的初始和后续行波分量，提出了基于故障行波过程的单端保护原理。使用小波变换对故障行波进行多分辨率分析，能够有效提取区内和区外故障行波的特征。最后，基于PSCAD/EMTDC对保护算法进行仿真验证，仿真结果表明该原理能正确判别直流线路区内和区外故障，且能够正确识别高阻接地故障，弥补了现有保护原理在高阻接地故障下灵敏性较低的缺陷。