Impedance-based fault location formulation for unbalanced primary distribution systems with distributed generation

State-of-the-art impedance-based fault location formulations for power distribution systems suppose that the system is radial. However, the introduction of new generation technologies in distribution systems, such as distributed generation, changes the direction of the system load flow from unidirectional to multi-directional. Therefore, it is necessary to extended current impedance-based fault location formulations to take into account the presence of generation units in the distribution system. Moreover, the distribution feeders are inherently unbalanced. This characteristic decreases accuracy of current fault location estimates that are based on sequence or modal phasor quantities. In this paper it is presented an extended impedance-based fault location formulation using phase coordinates. Computational simulations test on a typical unbalanced deregulated distribution system are presented and compared with state-of-the art techniques. The extended formulation is implemented numerically and a case study is presented to demonstrate the methods accuracy.