Investigation of a Rutherford cable using coated conductor Roebel cables as strands

Abstract

Coated conductor applications such as fusion magnets, particle accelerator magnets and generator windings require high current-carrying capabilities. This requirement can be fulfilled by various cable concepts using commercial long length REBCO coated conductors with high current-carrying performance. In the past few years, our group has successfully developed the Roebel cable concept for coated conductors. The design advantages of such a cable are high current-carrying capability and low alternating current (AC) losses. Unfortunately, for large-scale applications, the possibilities of a simple scale-up of the Roebel geometry are limited and additional design ideas are needed. One way to reach the required high currents is the Rutherford cable concept. In this concept a conductor is wound with transposition on a flat metal former. In order to design the former, the bending properties of the Roebel assembled coated conductor cables (RACC) must be measured and characterized. This allows the identification of a destruction-free interval for the Roebel cable, in terms of bending angle and transposition length. In this work we designed and assembled a demonstrator of a coated conductor Rutherford cable (CCRC) with three RACC cables. We measured the critical current and the AC losses of the cable demonstrator. Our results show that, despite still needing efforts in terms of reproducibility of the assembly process and of AC loss reduction, this design is a promising and viable solution for high current-capacity cables made of coated conductors.