基于电流突变量比值的高压直流输电线路纵联保护方案

针对现有的高压直流输电(HVDC)线路纵联差动保护可靠性不足且动作延时较长的问题，提出了基于电流突变量比值的HVDC线路纵联保护方案。该方案利用特定频率下直流滤波器组和HVDC线路中的电流突变量比值的大小识别故障发生的位置。当发生区内故障时，整流侧电流突变量的比值和逆变侧电流突变量的比值均在1附近；当发生区外故障时，整流侧电流突变量的比值和逆变侧电流突变量的比值中必有一个远大于1。仿真结果与现场录波数据测试表明，基于电流突变量比值的HVDC线路纵联保护方案能够在各种工况下准确快速地识别区内外故障。

Pilot HVDC line protection scheme based on ratio of superimposed current

Since the current differential protection for HVDC transmission line is of poor reliability and ope-rates with long time delay, a novel pilot HVDC line protection scheme based on the ratio of superimposed current is proposed. The ratio of superimposed current at specific frequency measured at DC filter to supe-rimposed current measured at DC line is used to identify the line faults. For internal faults, the ratios of superimposed current at rectifier side and inverter side are both close to 1, while for external faults one of the two ratios is always much greater than 1. The simulative results and the test with field data indicate that the proposed protection scheme can identify the internal and external faults accurately under various fault conditions.