Hybrid AC superconducting current limiter: small-scale experimental model

The recently developed ultralow AC loss superconducting wires have made possible the design of AC current limiters based on the transition from the superconducting state to the normal state by overstepping the critical current. The original superconducting limiter described is formed by two magnetically coupled copper windings connected in parallel through a superconducting noninductive coil which triggers the inductive limitation. A different number of turns for the two normal windings reduces the current through the superconductor and the cryogenic losses, and simplifies the superconducting cable. A magnetic circuit with variable coupling coefficient makes it possible to limit the thermal stresses on the superconducting coil during limitation. The design, optimisation and tests of a single-phase 150 V/50 A model are presented. It has successfully proved its operation