Fundamental design based on current distribution in coaxial multi-layer cable-in-conduit conductor

Takataro Hamajima, Makoto Tsuda, Tsuyoshi Yagai, Kazuya Takahata, Shinsaku Imagawa

Research output: Contribution to journalArticlepeer-review


An imbalanced current distribution is often observed in cable-in-conduit (CIC) superconductors which are composed of multi-staged, triplet type sub-cables, and hence deteriorates the performance of the coils. Therefore, since it is very important to obtain a homogeneous current distribution in the superconducting strands, we propose a coaxial multi-layer type CIC conductor. We use a circuit model for all layers in the coaxial multi-layer CIC conductor, and derive a generalized formula governing the current distribution as explicit functions of the superconductor construction parameters, such as twist pitch, twist direction, radius of each layer, and number of superconducting (SC) strands and copper (Cu) strands. We apply the formula to design the coaxial multi-layer CIC which has the same number of SC strands and Cu strands of the CIC for Central Solenoid of ITER. We can design three kinds of the coaxial multi-layer CIC depending on distribution of SC and Cu strands on all layers. It is shown that the SC strand volume should be optimized as a function of SC and Cu strand distribution on the layers.

Original languageEnglish
Pages (from-to)1299-1304+2
JournalIEEJ Transactions on Power and Energy
Issue number11
Publication statusPublished - 2009


  • Cable-in-conduit conductors
  • Coaxial multilayer conductors
  • Current distributions


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