Development of 6.6 kV-200 A DC reactor type superconducting fault current limiter

As a part of the 21st Century Frontier R&D Program in Korea being performed from 2001, a DC reactor type superconducting fault current limiter (SFCL) is being developed. The target of the first phase is to develop a 6.6 kV/200 A class 3-phase SFCL as a prototype for a 154 kV class. This prototype SFCL has a magnet wound with a high-T_c superconducting wire (Bi-2223) operating at 65 K. The magnet uses solenoid bobbins with grooves for the tape wire. Its inductance is about 84 mH. An AC-DC power converter was made with light trigger thyristor (LTT) having a phase controller. The maximum voltage is 7 kV. The DC reactor, which is cooled by sub-cooled nitrogen, uses a three phase transformer with dual tap for series connection with a power line. Through several experiments this SFCL shows current limiting performance about 50% of short circuit current at short run tests.