Ac loss analyses of superconducting power transmission cables considering their three-dimensional geometries

Numerical electromagnetic field analyses of superconducting power transmission cables consisting of coated conductors were made considering their three-dimensional spiraled structures. Thin strips of superconductor were wound spirally around a round former to represent a layer in a cable. The analyses were made for two-layer cables where the spiral pitch of the inner layer and that of the outer layer are different. A non-uniform lateral critical current density distribution, a trapezoidal distribution with shoulders, was assumed across each coated conductor. The calculated ac losses were compared with measured ones. The influence of the relative positions between the inner-layer coated conductors and the outer-layer coated conductors on the current distribution across each coated conductor as well as ac losses was discussed. The influence of the current distribution between layers, determined by the spiral pitches, on the ac losses was also studied.

► Electromagnetic field analyses were made for cables with spiral geometry.
► The calculated ac losses agree reasonably with the measured ones.
► The ac loss in a cable distributes along cable axis.
► The spiral pitches influence the current distribution and ac loss.