Impact of placement of inductive fault current limiters on synchronized operations of generators

Abstract

Judicious placement of inductive fault current limiters (IFCLs) in isolated power systems can increase the robustness of generator synchronization during and after short-circuit faults, while also improving continuity of power to the system loads. Our work defines optimal placements of IFCLs so as to protect the synchronization of multiple generators, and it defines the proper trip settings for the IFCLs so that they coordinate well with each other, and with the system's circuit breakers. Our work considers both radial and ring bus structures, but not mesh structures. The IFCL placement technique is demonstrated in a power network containing four buses in a ring arrangement. The system receives power from two main turbo-generators (36 MW each) and two auxiliary turbo-generators (4 MW each). In this system, the optimal locations for the IFCLs were found to be near the bus ties of the two larger generators. Further, the placement strategy for locating IFCLs in a power system with ring structure is developed. For this arrangement, fault currents were limited for all fault conditions while assuring maximum availability of power to the loads. Coordination between the IFCLs and the system circuit breakers is analyzed for IFCLs in these locations, and verified by simulation results.