Fault Point Locating Method of Hybrid Lines Based on Analysis of Comprehensive Characteristics of Single-end Electric Quantity and Transient Travelling Waves

摘要

The invention discloses a fault point locating method of hybrid lines based on analysis of comprehensive characteristics of single-end electric quantity and transient travelling waves, which mainly includes steps: phase-model transformation; looking up initial time of failure; extracting timing window data after the initial time; searching a reflected wave from the fault point and a reflected wave from a demarcation point in the timing window; and judging properties of the reflected waves. After failure of a hybrid line with cable and overhead line, by identifying and comparing comprehensive characteristics of the reflected wave from the fault point, primary and secondary reflected waves from the demarcation point in the single-end transient voltage and current travelling waves, it is rapidly judged whether the fault point is located in the overhead line segment or the cable segment, which is used to assist in switching decision for line reclosing.

主权项

1. A fault point locating method of hybrid lines based on analysis of comprehensive characteristics of single-end electric quantity and transient travelling waves, wherein, the method mainly includes the following steps:
step 1, performing phase-model transformation based on the single-end electric quantity, and reducing effect of inter-phase coupling of the transient travelling waves on section locating; step 2, utilizing wavelet transformation to detect a signal break point of transient voltage and current travelling waves as the initial time of failure; step 3, extracting timing window data after the initial time of failure of the voltage and current travelling waves, wherein size of the timing window is determined by cable length; step 4, searching all reflected wave heads with the same voltage/current polarity and close amplitudes in the timing window, and computing relative values uxf and ixf of various reflected and initial wave heads with the initial wave head of the voltage/current travelling waves as a benchmark; and step 5, judging properties of the reflected waves.