Long-Term Operation and Fault Tests of a 22.9 kV Hybrid SFCL in the KEPCO Test Grid

This paper reports on the operation test of a 22.9 kV hybrid superconducting fault current limiter (SFCL) in the KEPCO test grid. The SFCL works at a rated voltage and current of 22.9 kV and 630 A, respectively. There are two major objectives of the operation test: (1) long-term operation and (2) fault tests for protection coordination study. The operation lasted for more than a year. We experienced several times of cryostat suspension due to blackouts and false alarms due to sensor failures during the operation. We also carried out short circuit tests in the test grid, equipped with circuit breakers and a recloser. An artificial fault generator was used to generate fault currents. The tests showed that the SFCL, together with the recloser, functioned reliably under repeated faults. We also confirmed the reclosing capability of the SFCL. We have presented herein the operation details, cost of operation, short-circuit test results, and our plans for further tests for protection coordination.