行波保护作为直流线路的主保护其应用比较广泛,但由于它是单侧电气量的保护,保护范围需要通过定值整定来确定,且行波保护不能反应于高阻接地故障。文中在对行波传输原理进行分析的基础上,利用区内故障时线路两侧均有反向行波幅值大于正向行波幅值的特点,构成纵联行波方向保护。若线路两端保护的判断结果均为正向故障,则整流侧将迅速移相重启。RTDS仿真表明,所提出的纵联行波方向保护方案能够快速、可靠地识别线路区内外故障,具有整定方便、保护范围明确、能反应于高阻接地故障等优点,可作为直流线路主保护的有益补充。
In order to improve the performance of conventional traveling wave protection used in high voltage direct current(HVDC) lines,a novel traveling wave based pilot directional protection is proposed based on the fact that amplitude of the backward traveling wave is greater than that of the forward traveling wave on both ends of line under internal zone fault.If the two relays at both ends of HVDC line detect a forward direction fault,then control action is to retard the rectifier firing control into full inverter operation mode.RTDS simulation results show that the proposed scheme can discriminate internal and external zone faults rapidly and reliably.It has some advantages such as: easy setting,specific protective zone and high resistance grounding fault recognition.The protection scheme is feasible as a complement of conventional main protection of HVDC line.