Development of low loss High-T_c superconducting wires based on electromagnetic design and their application to AC power cables

1.不同灯丝排列方式Bi_（2223）超导带材在交流纵向磁场中的交流总损耗研究了不同灯丝排列方式Ag包覆Bi_（2223）超导带材在平行于带材长度方向的交流纵向磁场中的交流总损耗特性。用标准PIT工艺制备的超导带材的总损耗值与理论预测的椭圆超导体输运损耗（Q_<t-ellipse>）和测量的无输运电流磁化损耗（Q_<m0>）之和基本一致。而采用双轴轧制矩形变形工艺制备的截面丝带，在B0 &lt;7mT时，总损耗小于（Q <t-ellipse>+Q）<m0>值，这是因为在此范围内，输运损耗占总损耗的主要部分。由于磁化损耗对总损耗的贡献随磁场的增大而增大， ...更多信息 随着振幅B_0的增大，测量的总损耗与（Q_ +Q_）值之间的偏差<t-ellipse><m0>在高场强范围内变小。这些结果表明，在B_0&gt; 10mT的交流纵向场中，控制带段中灯丝的排列对降低总损耗几乎没有影响。除了控制带段的细丝布置之外，在77 K时，采用双通道超导体，研究了由Bi 2223超导带材组成的圆柱形导体的交流输运自场损耗。层圆柱形导体组成的银护套Bi 2223磁带。作为股线的多芯带以平行的方式排列在直径为10.5 mm的圆柱形线圈架上。导体中的损耗产生随层间间距和外层相邻带间间隙长度的增大而增大。从数值计算的损耗密度分布的每个周期的导体中，它是建议的损耗值的差异，每个导体是由于磁通分布由于自场和损耗产生的磁带股，不同的磁带股在导体中的排列。少

1.Total AC losses in Bi2223 superconducting tapes with different filament arrangements in AC longitudinal magnetic fieldThe total AC loss properties were investigated on the Ag-sheathed Bi2223 tapes with different filament arrangements in an AC longitudinal magnetic field applied parallel to the tape length. The total loss values in the tape prepared by standard powder-in-tube(PIT) process almost agree with the sum of the theoretical prediction of transport losses in an elliptical superconductor (Q_<t-ellipse>) and measured magnetization loss without transport current (Q_<m0>). On the other hand, for the tape with sectioned filament arrangements prepared by rectangular deformation process with two axial rolling, the total loss values are lower than the values of (Q_<t-ellipse>+Q_<m0>) at B_0<7 mT, because the transport losses are dominant component in total losses in this range. Since the contribution of the magnetization losses to total losses enhances with increasing the magnetic fie … More ld amplitude B_0, the deviation between the measured total losses the values of (Q_<t-ellipse>+Q_<m0>) becomes small in higher field range. These results indicate that the controlling a filament arrangement in a tape section hardly affect the reduction of the total losses in an AC longitudinal field with B_0>10 mT. In addition with controlling the filament arrangements of a tape section, reducing filament thickness and increasing the matrix resistivity by interfilamentary resistive barriers are important to reduce the total loss values in AC longitudinal magnetic field.2.AC transport losses in cylindrical conductors composed of Bi2223 superconducting tapesThe AC transport self-field losses at 77 K were investigated on the double-layer cylindrical conductors composed of Ag-sheathed Bi2223 tapes. The multifilamentary tapes as the strands are arranged in a parallel way on the cylindrical former with a diameter of 10.5 mm. The loss values are strongly influenced by the arrangements of tape strands in the conductors. The loss generation in conductors enhances with increasing of the separation between the layers and gap length between the adjacent tapes in the outer-layer. From the numerical calculations of the loss density distributions per-cycle in the conductors, it is suggested that the difference in loss values for each conductor is attributed to the magnetic flux distributions due to self-field and loss generations in tape strands, varying with the arrangement of tape strands in the conductors. Less