Influence of gaps in monolayer superconducting cable on AC losses

Abstract

AC transport loss in a core of superconducting power transmission cable has been investigated by numerical simulations. We assumed that the core consists of superconducting tapes distributed symmetrically on a cylindrical surface. It is well-known that the ideal geometry, from the point of AC-losses, would be a single uniform superconducting layer. However, the manufacturing of cable requires that superconducting tapes are separated from each other. On that account, the Brandt's method was used to study and evaluate how the size of gaps between tapes would influence the AC losses. The considered tapes have rectangular shape with aspect ratio similar to the filamentary zone of commercial Bi2223/Ag tapes. For this material the critical current density sharply decreases with magnetic field. Therefore, we have assumed a dependence of the critical current density on magnetic field in our calculations (jc(B) dependence). Our simulations show how the increasing of the gaps size results in an increasing of AC-losses. This can be used to find the compromise between an easy manufacturing of cable and the low AC-losses.