Investigation of Mechanisms Causing AC Losses with Long Time Constants in Large Superconducting Conductors

大型超导导体中长时间常数交流损耗的机理研究

• 批准号: 13680578
• 负责人: HAMAJIMA Takataro
• 金额: $ 0.38万
• 依托单位: Yamaguchi University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2001
• 资助国家: 日本
• 起止时间: 2001 至 2002
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-13680578/
• 关键词: AC Loss; Irregular Coupling Loss; Cable-in-Conduit Conductor; Sub-cable; Long Time Constant; Disorder of Cable; Contact Resistance; Strand Location

A large superconducting coil wound with Cable-in- Conduit (CIC) conductor causes both irregular AC losses that cannot be estimated from short conductor sample test results, and regular AC losses that are proportional to cable twisting pitch squared. We proposed a mechanism forming loops that generated the irregular losses. The CIC conductor is composed of several stages of sub-cables. If one strand on the surface of a sub-cable contacts another strand on the surface of the adjacent sub-cable, the two strands must encounter each other again at the LCM (Least Common Multiplier) distance of all staged cable pitches, and thereby a long loop is formed.We measured cross over point contact resistance between two strands making the long loop. The calculated time constants of the long loops were shorter than the observed ones.We orderly labeled all strands in CIC conductors for the SMES and the LHD. It was found that strands in a triplet were widely displaced from their original positions on one cross section, but contacted each other tightly on the other cross section. This fact suggests that the loop with the large displaced strand links irregularly with external field so that the loops cause the irregular AC losses. Moreover, it indicates that a contacting length of the large displaced strands can be quite long, giving rise to a low contact resistance for the loop, and leading to the long time constants. It is believed that the widely displaced strand are inherent in a CIC conductor.

用导管内电缆（CIC）导体缠绕的大型超导线圈引起不能从短导体样品测试结果估计的不规则AC损耗和与电缆扭转节距平方成比例的规则AC损耗。我们提出了一种机制，形成循环，产生不规则的损失。CIC导体由若干级子电缆组成。如果子电缆表面上的一股线与相邻子电缆表面上的另一股线接触，则两股线必须在所有分级电缆节距的LCM（最小公倍数）距离处再次相遇，从而形成长回路。计算得到的长回线时间常数比实测值要短。结果发现，在一个横截面上，三重链中的链从它们的原始位置广泛地移位，但在另一个横截面上彼此紧密接触。这一事实表明，具有大位移股线的回路与外场不规则地连接，使得回路引起不规则的交流损耗。此外，它表明，大位移股的接触长度可以是相当长的，从而引起回路的低接触电阻，并导致长的时间常数。据信，广泛移位的股线是CIC导体中固有的。

项目成果

T.Hamajima, et al.: "Long time constants of irregular AC coupling losses in a Large superconducting coil"IEEE Transactions on Applied Superconductivity. 12.1. 1616-1619 (2002)

T.Hamajima 等人：“大型超导线圈中不规则交流耦合损耗的长时间常数”IEEE 应用超导汇刊。

T.Hamajima, et al.: "A mechanism causing an additional AC loss in a large CICC Coil"IEEE Transactions on Applied Superconductivity. 11・1. 1860-1863 (2001)

T. Hamajima 等人：“在大型 CICC 线圈中引起额外交流损耗的机制”IEEE 应用超导汇刊 11・1（2001 年）。

浜島 高太郎: "大型CIC超電導導体の長時定数交流損失"山口大学工学部研究報告. 52・2. 7-11 (2001)

Takataro Hamashima：“大型 CIC 超导导体的长期恒定交流损耗”山口大学工学部研究报告 52・2（2001 年）。

T. Hamajima, N. Harada, T. Satow, H. Shimamura, K. Takahata, M. Tsuda: "Long time constants of irregular AC coupling losses in a Large superconducting coil"IEEE Transactions on Applied Superconductivity. 12-1. 1616-1619 (2002)

T. Hamajima、N. Harada、T. Satow、H. Shimamura、K. Takahata、M. Tsuda：“大型超导线圈中不规则交流耦合损耗的长时间常数”IEEE 应用超导学报。

Takataro HAMAJIMA, Hiroshi Shimamura, Youhei KAKUSHO, Makoto TSUDA, Naoyuki HARADA: "AC losses with long time constants in a large CIC superconductor"Memoirs of the Faculty of Engineering Yamaguchi University. 52-2. 7-11 (2001)

Takataro HAMAJIMA、Hiroshi Shimamura、Youhei KAKUSHO、Makoto Tsuda、Naoyuki HARADA：“大型 CIC 超导体中长时间常数的 AC 损耗”山口大学工学部回忆录。