高压直流输电线路边界高频电压信号衰减特性分析

高压直流输电线路两端安装的直流滤波器和平波电抗器形成了高频电压信号的线路边界，利用这种边界特性可以构成新型线路保护，但线路边界参数及配置方式的差异会对线路边界高频电压信号衰减程度造成影响。基于现有直流输电工程的直流滤波器与平波电抗器的参数及配置原则，研究了不同直流滤波器结构、不同平波电抗器配置方式以及直流滤波器与平波电抗器元器件不同参数对直流输电线路边界高频电压信号衰减特性的影响。结果表明，不同参数及配置形式的线路边界对高频电压信号均有较大衰减，可以依据高频电压信号在区内外故障时的差异构成新型直流输电线路保护。

Analysis on high frequency voltage signal attenuation characteristic of HVDC transmission line boundary

The line boundary of high frequency voltage signal is composed of DC filter and smoothing reactor installed at both ends of HVDC transmission line, which can be used to propose new principle based protections. However, the differences of component parameter and allocation principle affect the high frequency voltage signal attenuation of the line boundary. Thus, analysis of the attenuation characteristic is presented. Based on the present HVDC project component parameter and allocation principle of DC filter and smoothing reactor, this paper studies the high frequency voltage signal attenuation characteristic of HVDC transmission line with different DC filter structures, different arrangements of smoothing reactor, and different component parameters. The results show that HVDC line boundaries with different component parameters and allocation principle cause large attenuation of high frequency voltage signal, and the difference of high frequency voltage signal when internal fault and external fault occur can be used to form the novel HVDC line protections.