Study on recovery time of a superconducting fault current limiter with adjustable trigger current level

The recovery time of a transformer type SCFGL (Superconducting Fault Current Limiter) with adjustable trigger current level, is studied experimentally. The recovery time is defined as the required time of zero current period of SCFCL for recovery from its current limiting mode to its waiting mode. A trial SCFCL, which was designed and made, Is tested to measure the recovery time with various fault time. The experimental results show that the recovery time depends on the fault time. When the fault time is longer than 200 ms, the recovery time becomes shorter and approaches a certain value (a few ten ms) as the fault time is longer.