Fault location in combined transmission lines using traveling wave for smart recloser control

A traveling wave fault location method for combined transmission lines based on search algorithm of pre-value look-table is presented. In this method, it tries to practice upon the time difference of fault induced initial traveling wave detected at the two ends of lines and the default time mid-point for the search direction, then the fault section is determined through comparing with the time difference between the arrival time of each overhead line and underground cable connection point. Thus the fault point is calculated by the double ended fault location formula. Based on this, an recloser control scheme is used: recloser signal is locked when cable fault happens, otherwise, be opened. EMTP simulation results show that, this method can determine the accurate fault location, the error is no more than 50m. It is unaffected by transition resistance, fault type and fault location, can precisely realize smart re-closing and be strong practical.