Analysis on Protection Coordination of Protective Devices With a SFCL Due to the Application Location of a Dispersed Generation in a Power Distribution System

The increase of various dispersed generations (DGs) such as wind power and solar cell in a power distribution system has been reported to increase the short-circuit current. In addition, the introduction of the DG in a power distribution system is expected to affect the operation of the protective device as well. The superconducting fault current limiter (SFCL), which has been continuously studied for the reduction of the circuit breaker´s power burden, recently starts to be noticed as effective method to solve the fault current problem due to the introduction of the DG. Since the fault current limiting operation of the SFCL and the operations of the protective devices such as the over-current relay or the recloser are affected by the application location of the DG, the study on the protection cooperation of the protective devices with the SFCL considering the application location of the DG in a power distribution system is firstly required. In this paper, the protection coordination of the protective devices with a SFCL due to the application location of a DG in a power distribution system was analyzed. The experimental circuit to simulate the DG and the protective devices was designed and realized by using the power electronic switches. With the power distributed system assembled with the DG, the protective devices and the SFCL, the short-circuit tests were carried out. The lower resistance generation of the SFCL due to the decrease of the feeder current in case that the DG was applied into the middle point of the fault feeder was analyzed to cause the fault current not to decrease, which the lock-out operation of the recloser was confirmed to be less delayed compared to other application locations of the DG in a power distribution system.