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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 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 current transfer between coated conductors during the quench and thermal runaway process, an aspect that cross-sectional analysis cannot capture. On the other hand, quench and thermal runaway 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 developed a relatively simple method for quench and thermal runaway simulation of spiral coated-conductor cables. This method combines a thermal conduction equation that allows consideration of the longitudinal temperature distribution and heat exchange between the core and each coated conductor, with a circuit model that accounts for the longitudinal current distributions in the core and coated conductors. To account for current changes during ac operation, the core and each coated conductor were divided longitudinally, and the self- and mutual inductances for all elements were pre-calculated and used as an inductance matrix in the circuit model. Using this method, we investigate how various parameters of the spiral conductors, such as the number of layers, contact resistance, and core resistivity, affect its protection characteristics against quench and thermal runaway.
This work was supported by JST-ALCA-Next Program Grant Number JPMJAN24G1, Japan.
