含直流馈入的带并补电抗线路单相自适应重合闸适用性分析及故障识别方法

The Single-phase Adaptive Reclosure Applicability Analysis and Fault Identification Method of Transmission Lines with Shunt Reactors Including DC Infeed

含直流馈入的交流线路发生永久性故障时,如不能准确判定故障性质,将使交流线路再一次承受短路电流冲击,危害直流系统运行安全。针对这一问题,提出了一种基于并联电抗器故障相谐波电流特性的单相自适应重合闸判据。首先,分析了现有单相自适应重合闸判据在含直流馈入的交流系统中应用的适用性,并得出换流器发生换相失败后向交流系统注入的谐波分量可能会使现有单相自适应重合闸判据失效这一结论;其次,通过快速集合经验模态分解–希尔伯特(fast ensemble empirical mode decomposition-Hilbert,FEEMD-Hilbert)谱分析从流过故障相并联电抗器电流中分解出谐波分量,依据不同故障性质下等效电流回路的不同,提出了基于谐波电流幅值比的单相自适应重合闸判据;最后,基于PSCAD/EMTDC仿真实验验证了所提方法的有效性和实用性。

When a permanent fault occurs on an AC line with DC infeed,if the fault characteristic cannot be precisely determined,the AC line will withstand the short-circuit current impact again,jeopardizing the safety of DC system operation.To solve this problem,a criterion of single-phase adaptive reclosure based on characteristics of harmonic current in fault phase of shunt reactor is proposed.Firstly,the applicability of the existing criterion of single-phase adaptive reclosure in AC systems with DC infeed is analyzed,and a conclusion is drawn that the harmonic component injected into the AC system after commutation failure of the converter can invalidate the existing criterion of single-phase adaptive reclosure.Moreover,through the fast ensemble empirical mode decomposition-Hilbert(FEEMD-Hilbert)spectrum analysis,the harmonic component is decomposed from the fault phase current of shunt reactor.According to different equivalent current loops under various fault characteristics,a novel criterion of single-phase adaptive reclosure based on amplitude ratio of harmonic current is proposed.Finally,the effectiveness and practicability of the proposed methodare verified by PSCAD/EMTDC simulation results.