HYBRID AC SUPERCONDUCTING CURRENT LIMITER - SMALL-SCALE EXPERIMENTAL-MODEL

The recently developed ultralow AC loss superconducting wires have mad e possible the design of AC current limiters based on the transition f rom the superconducting state to the normal state by overstepping the critical current. The original superconducting limiter described is fo rmed by two magnetically coupled copper windings connected in parallel through a superconducting noninductive coil which triggers the induct ive limitation. A different number of turns for the two normal winding s reduces the current through the superconductor and the cryogenic los ses, 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, op timisation and tests of a single-phase 150 V/50 A model are presented. It has successfully proved its operation.