Performance verification of a practical fault current limiter using YBCO thin film

Aiming at a practical use of superconducting fault current limiter, a newly designed device which consists of YBCO thin films and normal conducting films has been developed. The configuration allows increase of the resistance of the YBCO film without excess heating and partial overvoltage. To verify the current limiting performance and the reliability of the device, an analogue simulator test with a condition equivalent to a typical distribution system has been conducted. The developed device can limit a fault current to a target level within a half cycle and the increasing speed of the resistance is fast enough to mitigate the current overshoot after the fault. The series and parallel connection of the unit devices are feasible to attain large capacity. These test results prove that the proposed device has sufficient performance for applying to an actual power system.