基于极波模量时差的高压直流输电线路自适应单端保护

针对目前高压直流输电线路单端保护在远端高阻接地故障时灵敏性下降可能造成保护拒动的问题，提出了一种基于极波模量时差的自适应单端保护方案。通过分析高压直流系统的边界作用和极波中耦合的线模和地模的传播特性，得到在区内故障和区外故障时不同的极波波形特征。文中分析了传统单端保护在远端高阻接地故障时灵敏性下降的原因，利用故障极波线模和地模时差内的极波波形斜率和幅值变化量，构造了自适应分段保护判据。基于PSCAD/EMTDC软件的仿真结果表明，所提保护方案能够有效地检测区内外故障，特别是在远端高阻接地故障时仍然保持足够的灵敏性。

Adaptive Single-end Protection for HVDC Transmission Line Based on Time Difference of Pole Wave Mode Components

Aiming at the problem that the sensitivity of the single-end protection of high-voltage direct current (HVDC) transmission lines decreases when the far-end high-resistance grounding fault occurs, which may cause protection failure, an adaptive single-end protection scheme based on the time difference of pole wave mode components is proposed. By analyzing the boundary effect of the HVDC system and the propagation characteristics of the coupled line mode and ground mode in the pole wave, the different pole wave waveform characteristics in the case of internal faults and external faults are obtained. The reason for the decrease in sensitivity of traditional single-end protection in the case of far-end high-resistance grounding fault is analyzed, and an adaptive segmented protection criterion is constructed using the pole wave waveform slope and amplitude variation within the time difference of line mode and ground mode of the fault pole wave. The simulation results based on PSCAD/EMTDC software show that the proposed protection scheme can effectively detect internal and external faults and still maintain sufficient sensitivity, especially in the case of far-end high-resistance grounding faults.