Driving Current and Fault Current Limiting Characteristics of Three-Phase Autotransformer Type SFCL in Power Distributed System Connected with Induction Motor

Generally, in case that the induction motor in power distributed system was driven, larger driving current due to starting operation of induction motor happened, which leads to drop of bus voltage and affects protective relays such as under voltage relay and over current relay. In this paper, to suppress the voltage drop and limit the driving current in power distributed system connected with induction motor, the countermeasure using superconducting fault current limiter (SFCL) was investigated. Among various SFCLs, three-phase autotransformer type SFCL, which was connected with three single-phase autotransformers through symmetrical arrangement of three dual iron-cores, was selected because it had advantage easily to adjust the operational current of SFCL by setting tap. Through the driving tests of induction motor and three-phase ground faults tests in simulated power distribution system, the driving current and fault current limiting operations of three-phase autotransformer type SFCL were analyzed to be performed effectively.