Fault Location in Unbalanced DG Systems using the Positive Sequence Apparent Impedance

The fault location techniques for power distribution systems (PDS) in use nowadays assume that the system has a radial power flow. Since new technologies in development, such as the distributed generation (DG), change this characteristic, it is necessary to adjust the already existing methods for fault location, since they show to be inefficient. Moreover, the unbalance between phases due to different loading at laterals is another issue that interferes in the fault location methodologies. In this paper, it is presented a new fault location method based on positive sequence apparent impedance. Computational simulations were made and the method was tested in two systems and compared with other existing fault location techniques in order to validate it. The basic characteristics of the method, the new algorithm and a variety of case studies are presented in the paper in order to illustrate its efficiency in unbalanced distribution systems with DG