AC Loss Measuring and Modeling of Single-Layer Roebel Tapes

The high-temperature superconducting (HTS) Roebel tape is a latest developed concept of high-current and low-loss HTS cables for high-power AC applications. In this work, samples of Roebel tapes with single superconducting layer are manufactured, tested, modelled, and analysed. In the experiments, the critical current degradation and the transport AC losses are measured. In the simulation, with the 3D finite element method (FEM) models based on the T-A formulation, the transport AC losses are calculated and compared with the experimental data, and the current distribution is analysed in detail. This model is then used to simulate long HTS Roebel tapes which could be used in practice and calculate the transport AC losses. The losses are found over 30% lower than that of the normal HTS ReBCO tapes, which verifies the loss-reduction performance of the HTS Roebel tapes. This work provides both experimental and simulation proof of the advantage of the HTS Roebel tape as a high-current and low-loss HTS cable. It could potentially become the key to the compact fusion magnets which require high power density and suppressed losses.