A new active method for ground fault location in small current grounding system

A new method for single-phase grounding fault location in small current grounding system is proposed, in which thyristor-based signal generator (SG) and signal detectors (SD) are included. The thyristor-based SG is connected between the phase line and ground, and SDs are arrayed along the distribution lines. After a single-phase grounding fault occurs, any thyristor connected between non-faulted phase and ground will be triggered. An active and highly distinguishable current is superimposed on line current. Based on strength estimation and feature analysis of the active signal, double-subtraction algorithm is proposed, detection parameters are selected, and the detection criterions are determined. At last, sensitivity analysis and verification studies demonstrate the efficiency and reliability of this method, which meets the demand of the practical engineering very well.