AC Loss Reduction in Round HTS Cables Achieved by Low-Cost Filamentization of Tape Conductors

Knowledge of the ac loss generated in a superconducting cable during variation of magnetic field is essential when considering its use in pulsed magnets. In round high-temperature superconducting (HTS) cables made from coated conductor (CC) tapes, the hysteresis loss is proportional to the tape width. Then an effective measure for reducing the loss is the division of the superconducting layer into parallel filaments. We investigated the ac loss in short models of round cables, containing in different arrangements two layers of 10 standard helically laid tapes. At magnetic field amplitudes surpassing 0.1 T the loss did not depend on the cable architecture, in agreement with simple analytical prediction. Substantial reduction of magnetization loss was obtained in the cable models from novel coated conductor (CC) tapes with a low-cost filamentized REBCO layer produced in an industrial process utilizing a special 3D patterned metal substrate. Further research should address the improvement of critical current and optimization of metallic layers, allowing a migration of current between filaments without substantial increase of coupling loss.