Fault Sensing of the Distribution Cable Feeders by Time-Domain Measurements

Power distribution cable feeders are prone to faults due to the poor working environment and internal defects. Considering the structure and electrical parameters of the typical distribution three-core cable, a fault sensing method is proposed. The fault sensing in this article includes three aspects: fault cable detection, fault phase identification, and fault resistance estimation. The grounding line currents of cable feeders are first analyzed in different neutral grounding modes. Based on the amplitudes and directions of the grounding line currents, a fault feeder detection criterion is then presented. Finally, based on the equivalent circuit of the fault cable, an algorithm for identifying the fault phase is developed by estimating the fault resistance. The experimental model of the distribution cable feeders is created by real time digital simulation (RTDS). Various fault experiments are carried out. The results show that the neutral grounding modes and fault conditions have little effect on the proposed method.