Applying Dynamic Load Estimation and Distributed-parameter Line Model to Enhance the Accuracy of Impedance-based Fault-location Methods for Power Distribution Networks

Precise load modeling and load value estimation at each node of power distribution systems are very important for determining the exact location of fault in impedance-based fault-location algorithms. In this article, a modified impedance-based fault-location algorithm is proposed by applying dynamic load estimation and distributed-parameter line model. The load value at each node is estimated by its load factor and power factor. In the proposed fault-location algorithm, the power distribution system and power factor of each node are estimated first, just before the fault, using the recorded data of voltage and current at the beginning of the main feeder. Then, using this information, the initial location of the fault is obtained by analyzing each section. In this process, multiple positions for the fault can result. Thus, the faulted section is determined by analyzing the operation of protective equipment, i.e., fuses, fault indicators, and reclosers, performed by investigating the current patterns at the beginning of feeder. The performance of the proposed method is evaluated based on a real feeder in an Iranian distribution network under different fault conditions. The obtained results show the efficiency and accuracy of the proposed method.