Conductor and Element Design: Minimizing Recovery time in Superconducting Fault Current Limiters

For Navy ship electrical systems there is a need for a new electrical component, a fault current limiter, that can provide several ”automatic” functions. Presently, fault detection takes about 80 microseconds with the right instrumentation. Several kinds of faults have short duration, but the difficulty is riding through these faults, especially with electronic switches, which have distinct voltages and current levels, above which the components fail or turn off. If the fault is not of a short duration, then it would be good to limit the fault current long enough to automatically implement fault management to isolate the fault, perform diagnosis, and allow for power re-routing if possible to maintain a combat state. It would be preferable to do this in less than 100 milliseconds, if possible. If ride-through or re-routing is not possible it would be useful to provide current limiting until a mechanical breaker has time to respond. In addition, if the current is limited, smaller current breakers can be used and distributed around the ship to give more opportunities for a re-routing of the current. A superconducting fault current limiter enables all of these functions “automatically”. The objective of this SBIR Phase I is to develop a system concept design for a YBCO coated conductor based superconducting fault current limiter for Navy ship applications.