Accuracy improvement of impedance-based fault locating method in distribution systems with DGs considering loss of laterals and load variations.

Fast and accurate fault location methods will accelerate power system restoration process and then cause improvement on availability and reliability indices. Presenting a modified scheme in order to improve accuracy of impedance-based fault location method in electric power distribution systems (EPDS) equipped with distributed generation (DG) units is the main goal of this paper. To achieve this goal, an iterative algorithm is introduced to compensate load variations. Also, a method is presented based on forward/backward sweep load flow to consider loss in all laterals of EPDS. Then, fault location will be determined by using a comprehensive method that extracts a fifth-order algebraic equation for each type of fault. This method will be modified to consider the presence of DGs in EPDS. In this paper, all the specific characteristics of real distribution systems such as unbalanced nature of network and loads, different types of loads, presence of multi-phase laterals, and capacitive effects of distribution lines are taken into account. The proposed scheme uses only 1 measurement unit at the main substation and 1 measurement unit at the DG bus. In this paper, modified IEEE 34 node test system is simulated by using PSCAD/EMTDC software, and it is used as a test system to evaluate the performance of the proposed method. Different scenarios such as the effect of fault distance, fault type, different fault resistances, and measurement unit errors are evaluated. The results indicate usefulness and precision of the proposed scheme. [ABSTRACT FROM AUTHOR]