AC loss characteristics of superconducting power transmission cables: gap effect andJc distribution effect

Abstract

Four groups of superconducting power transmission cables composed of coated conductors with 4.0 mm widthand 2 µm superconductor thickness have been designed, including mono-layer, two-layer, four-layerand six-layer cables. In each group, three types of cables have been constructed with gapsof different size between adjacent coated conductors, which are classified into small gap,medium gap and large gap. Moreover, different lateral critical current density(Jc) distributions, specifically a uniform distribution and a trapezoidal distribution with a slopingshoulder, have been assumed while calculating the AC losses of these cables numerically byusing a one-dimensional FEM model. Numerical results show that AC losses in mono-layercables are significantly influenced by gaps between coated conductors as well as lateralJc distribution, while cables with many layers are hardly affected by them. Thisproves that small gaps between coated conductors are not absolutely essentialto reduce AC losses in multi-layer cables, and a sloping shoulder of theJc distribution is more allowable in multi-layer cables than in mono-layer cables.The AC loss distributions among layers in six-layer cables are presentedand the reasons for different influences of the gap as well as the lateralJc distribution in mono-layer and multi-layer cables are discussed.