Analysis of Balanced Three-Phase Current Distributions in a Tri-AxialCable
Analysis of Balanced Three-Phase Current Distributions in a Tri-AxialCable
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三轴电缆中三相电流平衡分布分析
DOI：
10.1109/tasc.2005.864267
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发表时间：
2006
影响因子：
1.8
通讯作者：
M. Tsuda
中科院分区：
文献类型：
--
作者：
T. Hamajima;T. Yagai;M. Tsuda
与传统铜电缆相比，高温超导（HTS）电缆由于损耗低且结构紧凑而受到研究。三相电缆通常由三根单相同轴电缆组成。近年来，由三个同心相组成的三轴电缆得到大力发展，因为与三相单相电缆相比，它具有高温超导带用量减少、泄漏场小、泄漏热损失小等优点。然而，由于三相电流层半径的差异，三轴电缆中的三相电流存在固有的不平衡性。电流的不平衡会造成电缆的附加损耗和较大的漏磁场，使电能质量恶化。因此，我们引入更多的变量来获得平衡三相电流和三轴电缆各相电流均匀分布的解。我们提出了一种由两个具有不同绞距的纵向部分组成的三轴电缆，因此变量的数量增加了。我们推导出满足平衡三相电流和均匀电流分布的一般方程，作为绕组节距的函数。最后我们将一般方程应用于最简单的电缆并找出合理的绞距
High Temperature Superconducting (HTS) cables have been studied because of low loss and compactness, compared with conventional copper cables. Three-phase cables are usually composed of three single-phase coaxial cables. Recently, a tri-axial cable, composed of three concentric phases, has been intensively developed, because it has advantages such as reduced amount of HTS tapes, small leakage fields and small heat loss in leak, compared with the three single-phase cables. However, there is an inherent imbalance in the three-phase currents in the tri-axial cable due to the differences in radii of the three-phase current layers. The imbalance of the currents causes additional loss and large leakage field in the cable, and deteriorates the electric power quality. Therefore, we introduce more variables to obtain the solutions of the balanced three-phase currents and homogeneous current distribution in each phase of the tri-axial cable. We propose a tri-axial cable composed of two longitudinal sections with different twist pitches, and hence the number of variables increases. We derive general equations satisfying both the balanced three-phase currents and homogeneous current distribution, as functions of winding pitches. Finally we apply the general equations to the simplest cable and find out reasonable twist pitches