Fabrication and evaluation of conductor cables using Ag-sheathed high-Tc superconductor tapes

研究了银包覆多纤带自场的交流输运损耗。银包覆多纤带是最有希望用于输电电缆股的材料。实验结果用Norris理论解释了具有相同临界电流的椭圆超导体，几乎不受灯丝数或超导体几何形状的影响。尽管对损耗行为的主要贡献来自迟滞损耗，但灯丝扭转对e灯丝的影响并不显著，也不均衡损耗中的电流分布。本文提出了一种计算无磁场磁芯形状、电流分布和磁场分布的新方法。因此，对于具有任意截面几何形状的直超导体带，以电流幅值10为参数的sell场的交流输运损耗。交流传输损耗为。矩形带在接近临界电流的高10值时表现为薄条状超导体，而随着10的降低，表现出逐渐偏离。矩形带宽厚比的减小使偏差更加显著。应用该方法计算了两种不同灯丝排列方式的7丝带的交流输运损耗。我们将测量结果与银包Bi2223带的损耗实验行为进行了比较，发现损耗密度分布的计算结果可以解释测量到的损耗。当灯丝数从7根增加到37根时，灯丝排列对损耗行为的影响被抑制。利用这种方法，我们对以矩形超导体带为股的单层或多层并联导体电缆模型的损耗进行了数值计算。电缆导体的损耗值受圆柱形成缆器上的带隙或每层中面对面带之间的分离的强烈影响。结果表明，改进胶带和电缆结构，即在电缆导体中布置超导磁芯，对抑制交流输电电缆导体中产生的损耗具有重要意义。少

We investigated the AC transport losses in self-fields for Ag-sheathed multifilamentary tapes that are the most promising for the strands of power transmission cables. The experimental results are explained by the theory of Norris for an elliptical superconductor with the same critical current, nearly independent of filament number or superconductor geometry. The filament twist neither causes notable influence on the e filaments, although the main contribution to the loss behavior nor equalizes the current distribution in th losses comes from the hysteresis loss.We proposed a new method to calculate the shape of field-free core, the current distribution and. accordingly the AC transport losses in sell fields as a parameter of current amplitude 10 for straight superconductor tapes with the arbitrary sectional geometry. The AC transport losses for. rectangular tapes behave as a thin strip superconductor in high 10 values near critical current, while showing a gradual deviation from this … More behavior as 10 is lowered. A decrease in the aspect ratio of width to thickness in the rectangular tape makes the deviation more remarkable. We applied this method to calculations on the AC transport losses for two kinds of 7-filamentary tapes with different filament arrangements. We compared the results with the experimental behaviors of the losses for Ag-sheathed Bi2223 tapes, and found that the measured losses are explained by the calculated results of loss-density distribution. The influence of filament arrangement on the loss behaviors is suppressed as the filament number increases to 37, from 7.Using this method, we made numerical calculations on the losses for models of parallel-conductors cables composed of a single- or a multi-layer configurations using rectangular superconductor tapes as the strands. The loss values of cable conductors are strongly influenced by the tape gap on a cylindrical former or a separation between the face-to-face tapes in each layer. The results suggest that the improvement of tape and cable structure, i.e., the arrangement of superconducting cores in the cable conductors, is important to suppress the losses generating in the cable conductors under AC current transmission. Less