Effects of Distributed Generators on Impedance-based Fault Location Algorithms

Impedance-based fault locating algorithms assume a radial distribution feeder when computing the distance to a fault. With increased penetration of distributed generators (DGs) to the distribution grid, this assumption is violated. Short-circuit current to a fault comes from two sources, the utility substation and DGs. Ignoring the latter term when the fault is located downstream from DGs will adversely affect the accuracy of location estimates. Therefore, this paper aims to evaluate the impact of DGs on the accuracy of existing impedance-based fault location algorithms. The goal is to understand how different factors such as DG technology, MVA size of the DG unit, DG interconnect transformer, tapped loads, location of the fault from the DG unit, and fault resistance affect fault location in the presence of distributed generators.