A Novel Fault Location Algorithm for Hybrid Lines Based on Corrected Travelling Wave Time Intervals

Distribution hybrid lines, especially the underground cable sections, require higher fault location accuracy. Researches have shown that the length error of overhead lines has little effect on the online measurement of cable wave velocity, while the impact on the fault section identification process cannot be ignored, and the error factor of the overhead line length need to be considered to implement the correction of the time interval; utilize the fault point-section terminal (FST) fault location mode to replace the conventional fault point-line terminal (FLT) mode can effectively eliminate the fault location error and the offset of the line inspection point caused by the length error of the overhead line. Based on the above analysis, this paper proposes a corrected time interval and FST mode based travelling wave fault location algorithm for hybrid lines. The line inspection points could be accurately located by utilizing the actual measured time difference of the initial fault travelling wave reaching the measuring end and the corresponding fault section of each corrected time interval, and combining the online actual measured cable wave velocity under the condition of considering the length error of the overhead line. The simulation results indicate that the method can effectively implement the fault location of the hybrid line of the distribution network, and the result of which is accurate and reliable.