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Description
Spiral coated-conductor cables feature a structure where HTS coated conductors are wound in layers around a metal core. Their high thermal stability, high current density, and high mechanical flexibility make them promising candidates for applications in magnets and electrical machines. In particular, spiral copper-plated striated coated-conductor cables (SCSC cables) are expected to be applied in ac environments due to their multifilament structure, which reduces ac losses and tape magnetization.
When considering cable design, numerical analysis techniques for evaluating electromagnetic and thermal characteristics, such as ac losses, quench, and thermal runaway, are important. Conventional analyses of spiral coated-conductor cables often employ cross-sectional models that do not account for the cable's intricate three-dimensional shape. However, the three-dimensional spiral winding configuration of coated conductors significantly influences their electromagnetic and thermal characteristics. On the other hand, numerical analysis that fully simulates the cable's three-dimensional geometry is impractical from a computational load perspective. Therefore, an appropriate modeling technique capable of considering the cable's three-dimensional geometry is required.
We have developed an electromagnetic field analysis model and a quench analysis model for SCSC cable considering cable’s three-dimensional geometry. The electromagnetic field analysis model is primarily used for calculating ac losses in SCSC cables. The model enables visualization of electromagnetic phenomena when SCSC cables carry alternating current under external ac magnetic fields—conditions that most closely resemble actual application environments. A key feature of this model is its ability to evaluate ac losses considering the current distribution among layers in the SCSC cable. This is achieved by combining the finite element method with a simplified circuit model. The quench analysis model calculates the longitudinal temperature distribution of the coated conductors and core constituting the SCSC cable, along with the heat exchange between them, using the heat conduction equation. It also represents the SCSC cable as a circuit model consisting of resistances and inductances to compute the current distribution. By iterating between temperature distribution calculations and current distribution calculations, it enables the evaluation of quench phenomena when an alternating current is applied to the SCSC cable.
This work was supported in part by JST-ALCA-Next Program Grant Number JPMJAN24G1, Japan, and supported in part by JSPS KAKENHI Grant Number JP22K14238.