Study on Application Method of Superconducting Fault Current Limiter for Protection Coordination of Protective Devices in a Power Distribution System

In this paper, the application method of superconducting fault current limiter (SFCL) for the protection coordination of the protective devices in a power distribution system was analyzed. The SFCL has been announced as better solution among many methods to limit a fault current effectively, which has continuously increased due to more complex network of a power system. However, the application of the SFCL in a power system affects the operation of the protection devices and the protection coordination, which requires the study on the protection coordination of the protective devices considering the application of the SFCL in a power distribution system. In this paper, the methods to maintain the protection operation of the protective devices due to the SFCL's application in a power distribution system were investigated through some case studies considering the time current curve (TCC) of the protection relay. The setting current and the lever among the setting parameters of the protective devices to keep the protection coordination in a power system with a SFCL were selected. Through the analysis on the TCC curves, the higher pick up current and the lower time lever values could be confirmed for protection coordination in case that the SFCL was introduced in the power system with the fixed impedance of the SFCL.