METHOD FOR DETECTING SINGLE-PHASE ARCING-GROUND FAULT AND PHASE FAILURE IN RESONANCE-GROUNDED-NEUTRAL DISTRIBUTION MAINS

摘要

FIELD: power engineering; detecting single-phase arcing-ground fault in resonance-grounded-neutral distribution mains.;SUBSTANCE: method involving facilitated procedures for detecting single-phase arcing-ground fault and phase failure enabling real-time monitoring of supply mains includes recording of phase-to-ground voltages across distribution mains followed by their analysis to determine derivatives of phase-to-ground voltages and comparison of their polarities; if they coincide and derivatives exceed setting value (double maximum of line voltage derivative), RMS value of phase-to-ground voltage is evaluated within 2 ms since last derivative of phase-to-ground voltage has reached setting value, RMS-to-average (Uav) and RMS-to-mean (Um) voltage ratio is found; if this ratio exceeds factor K (Uav/Um K) as found from expression K = [3.17 + 0.067 (K_L - 30)Ks] for mains capacitance compensating factor K_l between 30 and 100% and K = [7.86 - 0.067(K_l - 100)Ks] for K_l between 100 and 130%, where Ks ≅ 0.8 - 0.9 is certain safety factor assumed to be slightly lower than 1, then this fault is recorded and if two or more such faults are detected, then single-phase arcing-ground fault and faulty phase are recorded.;EFFECT: facilitated procedure, enhanced speed of fault detection.;1 cl, 10 dwg