新型高温超导扭绞缆线的临界电流评估方法及其特性研究

高温超导缆线是研究各种大电流高温超导应用的基础.将超导材料通过不同方式组合成复合导体,不仅可以让缆线的载流量得到提升,更可以在机械强度和电磁特性等方面得到改善.在国内外众多研究缆线的团队中,上海交通大学超导团队提出了一种基于YBCO高温超导带材的新型高温超导扭绞缆线结构.这种结构在理论上不仅实现了载流量和机械强度的平衡,还通过扭绞改善了电磁特性4-5].但是目前对于这种缆线的研究还处于起步阶段,特别是对其临界电流特性的研究.因此为了研究新型高温超导扭绞缆线的临界电流特性,本文从新型高温超导扭绞缆线的结构出发,通过仿真和实验两个角度对新型高温超导扭绞缆线的临界电流特性进行研究.在仿真方面,用H方程法计算缆线的临界电流,并探究扭绞节距是否会对临界电流的衰减产生影响.在实验方面,研究出了一种最适合于该缆线结构的临界电流评估方法“SVWE-copperwire-TU”.并用该方法测量了新型高温超导扭绞缆线的临界电流特性.本研究的结论对于后续制作更大电流的新型高温超导扭绞缆线具有重要意义.

Study on Critical Current Evaluation Method and Characteristics of a Novel High Temperature Superconducting Twisted Cable

High temperature superconducting (HTS) cable is the basis of studying various high current HTS applications. Combining superconducting materials into composite conductors in different ways can not only improve the current carrying capacity of cables, but also improve the mechanical strength and electromagnetic characteristics. Among many research teams at home and abroad, the superconducting team of Shanghai Jiao Tong University has proposed a novel HTS twisted cable structure based on YBCO HTS tape. In theory, this structure not only achieves the balance of current carrying capacity and mechanical strength, but also improves the electromagnetic characteristics through twisting. However, the research on this kind of cable is still in its initial stage, especially on its critical current characteristics. Therefore, in order to study the critical current characteristics of the novel HTS twisted cable, this work starts from the structure of the novel HTS twisted cable, and then studies the critical current characteristics of it from both simulation and experimental perspectives. In the aspect of simulation, the critical current of cable is calculated by H equation method, and the influence of the twisted pitch on the decay of the critical current is investigated. In terms of experiment, a critical current evaluation method "SVWE-copper wire-TU" was developed, which is most suitable for this cable structure. The critical current characteristics of the novel HTS twisted cable are measured by this method. The conclusions of this study are of great significance for the subsequent fabrication of novel HTS twisted cables with higher current.