Applying superconductive fault current limiter to minimize the impacts of Distributed Generation on the distribution protection systems

Distributed Generation Resources are increasingly used in distribution systems due to their great advantages. The presence of DG, however, can cause various problems such as miss-coordination, false tripping, blinding and reduction of reach of protective devices. Using superconducting fault current limiters (SFCLs) is one of the best methods to minimize these problems comparing to the other conventional methods. In this paper, with defining the protection evaluating indices, the number of protection problems and the worst case among them are specified. Thus, the optimum impedance of limiter is determined. The suitability of the selected value of the minimum impedance is verified by the resolving all of the protection problems. Furthermore, comparison between the three types of superconductive limiters, i.e. resistive, inductive, and impedance has been done. According to the study, to control the fault current contribution of a DG resource and minimize the protection issues, the limiter which is placed in series with the DG unit has the most beneficial impact among other locations. Efficiency of the proposed approach is evaluated with various simulations on a real radial distribution system in two cases, having one DG unit and also two DG units with different capacities.