HYBRID SUPERCONDUCTING AC CURRENT LIMITER EXTRAPOLATION 63-KV-1 250-A

Following the developement of a.c. superconducting wires a.c. current superconducting limiters have emerged. These limiters limit the fault currents nearly instantaneously, without detection nor order giver and may be suitable for high voltages. They are based on the natural tran sition from the superconducting state to the normal resistive state by overstepping the critical current of a superconducting coil which lim its or triggers the limitation. Our limiter device consists essentiall y of two copper windings coupled through a saturable magnetic circuit and of a non inductively wound superconducting coil with a reduced cur rent compared to the line current. This design allows a simple superco nducting cable and reduced cryogenic losses but the dielectric stresse s are high during faults. A small model (150 V/50 A) has experimentall y validated our design. An industrial scale current limiter is designe d and the comparisons between this design and other superconducting cu rrent limiters are given.