Precise load modeling and load value estimation at each node of power distribution systems (PDSs) are very important for determining the exact location of fault in impedance based fault location algorithms. In this paper, 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 (LF) and Power Factor (PF). In the proposed fault location algorithm, first, LF and PF of each node are estimated just before the fault using the recorded data of voltage and current at the beginning of the main feeder. Then, using this information, initially location of fault is obtained by analyzing each section. In this process, it can be resulted in multiple positions for fault. Thus, the faulted section is determined by analyzing the operation of protective equipments, i.e.; fuses, fault indicators and reclosers. It is 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 distribution network of Iran under different fault conditions. The obtained results show the efficiency and the accuracy of the proposed method.

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