When exposed to time-dependent magnetic fields, REBCO Roebel cables generate AC loss resulting from both magnetic hysteresis and induced interstrand coupling currents. Until now, the AC loss was computed in a two-dimensional approximation assuming fully coupled or decoupled strands, and a finite inter-strand resistance could be simulated only with three-dimensional models. In this work, we propose a homogenization procedure that reduces the three-dimensional geometry of the Roebel cable to two-dimensions, without ignoring connections between the strands. The homogenized cable consists of two parallel 'monoblocks' with an anisotropic resistivity. The proposed model enables computation of AC coupling loss without the need for complex three-dimensional simulations. For experimental validation, a Roebel cable with soldered strands was prepared. The inter-strand resistance was determined by applying a transverse current and measuring the voltage profile. Additionally, the AC magnetization loss of the cable was measured over a wide range of frequencies using a calibration-free technique. With the measured inter-strand resistance as input parameter, the monoblock model gives a good estimate for the AC loss, even for conditions in which the coupling loss is dominant.

中文翻译：

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用于计算部分耦合 Roebel 电缆交流损耗的各向异性整体模型

当暴露于随时间变化的磁场中时，REBCO Roebel 电缆会因磁滞和感应的股间耦合电流而产生交流损耗。到目前为止，AC 损耗是在假设完全耦合或解耦的股线的情况下以二维近似计算的，并且只能使用三维模型来模拟有限的股线间电阻。在这项工作中，我们提出了一种均质化程序，将 Roebel 电缆的三维几何形状减少到二维，而不会忽略股线之间的连接。均质电缆由两个具有各向异性电阻率的平行“单体”组成。所提出的模型无需复杂的三维仿真即可计算交流耦合损耗。为了进行实验验证，准备了带有焊接绞线的 Roebel 电缆。通过施加横向电流并测量电压分布来确定链间电阻。此外，还使用免校准技术在很宽的频率范围内测量了电缆的交流磁化损耗。将测得的股间电阻作为输入参数，整体模型可以很好地估计交流损耗，即使在耦合损耗占主导地位的情况下也是如此。