双极高压直流输电线路行波差动保护原理及方案

针对现时保护方案的不足,提出了双极高压直流输电系统直流线路行波差动保护原理和方案。该方案利用直流线路两端反行波的1模分量构造行波差动保护判据,其中行波差动量和制动量分别利用线路整流侧反行波和逆变侧传播来的反行波间的差量及二者之和构成,并利用整流侧电流的零模分量来判断双极运行时的故障线路。仿真结果表明,所提出的保护判据具有更高的灵敏度、可靠性和安全性,最大抗过渡电阻能力提高到500？,并且在各种故障情况下都能够正确动作。

Traveling Wave Theory and Differential Protection Scheme for BipolarOperating HVDC Transmission Lines

Aiming at the insufficiencies of current protection program for the HVDC transmission system, this paper proposes a travelingwavebased differential protection scheme for bipolaroperating HVDC transmission lines. Both the backward traveling waves (BTWs of mode 1 at two terminals are employed to establish the discriminative criterion, in which the operating traveling wave is the differential of BTWs between two terminals while the sum of them is for the restraint wave. The currents of zeromode at the rectifier terminal are utilized for faulty line detector in the bipolaroperating mode. Simulation results show that the proposed protection has the advantages of higher sensitivity, reliability and security, and its maximum fault resistance is up to 500 Ohm. The new protection works well in various fault conditions.