中文摘要：

配电线路区内、外故障时暂态分量频谱能量差异不明显，使得暂态保护原理难以应用于配电线路单端保护。通过行波网格法分析了配电线路区内、外故障行波的传播规律及特点，提出在线路边界处并联接入适当通频带的带通滤波装置，以此强化区内、外故障时故障暂态电压频谱能量差异。PSCAD／EMTDC仿真和模拟试验结果表明：安装了带通滤波装置的配电线路区外故障时，通频带内的故障行波流经带通滤波装置后发生较大衰减；区内故障时故障行波未通过带通滤波装置而几乎没有衰减，区内、外故障时暂态电压分量频谱能量差异非常明显。利用这种差异可以准确区分区内、外故障，这为暂态保护原理在配电线路单端保护中的应用提供了有效的理论依据和解决方案。

英文摘要：

Since there is no significant difference of the transient component spectral energy between the internal and external faults in distribution line, the transient protection theory is difficult to be applied in the single-ended protection of distribution line. Based on the analysis of the traveling wave of internal and external faults in the distribution line by grid metnod, me paper proposes a new method connecting the band pass filters at line boundaries in parallel to strengthen the difference of transient voltage spectrum energy between internal and external faults. The results of PSCAD/EMTDC simulation and physical test prove that： when external faults happen, great attenuation occurs after the traveling wave in pass band goes through the band pass filter. But for internal faults, the traveling wave just has little attenuation since it does not go through the band pass filter, thus the difference of transient voltage spectrum energy in the frequency band between internal and external faults is obvious.This method can distinguish internal faults from external faults, and provides an effective theoretical basis and solutions for distribution line single-ended transient protection.