脉冲注入法和单端故障行波法相结合的直流输电系统接地极线路故障测距

分析了直流输电系统在单极运行方式下，接地极线路故障暂态行波和外部注入脉冲信号在接地极线路上的传播过程。以此为基础，提出一种将脉冲注入法和单端故障行波法相结合的接地极线路故障测距方案。首先通过在换流站直流中性母线处监测接地极线路故障暂态行波识别线路是否发生故障，在线路故障暂态过程结束后从中性母线向线路注入脉冲信号。根据脉冲注入法得到初步测距结果，并以此确定故障区段。然后，根据确定的故障区段，进一步用单端故障行波法再次获得测距结果。最后，对两次测距结果取平均值，作为最终测距结果。以PSCAD/EMTDC为仿真平台，搭建了直流输电系统在单极运行方式下的接地极线路故障测距仿真模型。并借助Matlab对仿真波形数据进行分析，表明所提出的接地极线路故障测距方案是可行的。

Fault location of HVDC grounding electrode lines based on combination of pulse injection method and single-ended fault travelling wave method

The propagation process of the fault transient traveling waves and the external injected pulse signals in the grounding electrode lines of high-voltage direct current (HVDC) transmission system in monopole operation mode is analyzed. On this basis, a fault location scheme for grounding electrode lines is presented based on the combination of pulse injection method and single-ended fault travelling wave method. The scheme identifies firstly whether the electrode lines is faulted by monitoring the electrode lines fault transient traveling wave on the converter station DC neutral bus. After the circuit fault transient process finished, a pulse signal is injected from the neutral bus. The preliminary result is obtained according to the pulse injection method by which the fault location section is determined. Then, according to the fault location section, the second result is obtained by the single-ended fault travelling wave method. The final measured result is the average of two location results. On the PSCAD/EMTDC simulation platform, the monopole HVDC transmission system simulation model is built for fault location analysis of grounding electrode lines. Matlab is used to process the simulation waveform data, indicating that the proposed fault location scheme for grounding electrode lines is feasible.