Critical state solution of a cable made of curved thin superconducting tapes

TL;DR

This paper presents a critical state model for calculating current, field distributions, and AC losses in curved superconducting tapes, accounting for spatial variations in critical current density, relevant for power cable applications.

Contribution

It introduces a novel method that models curved tapes with variable critical current density, enhancing accuracy in predicting AC losses in superconducting cables.

Findings

Curved tapes behave like an infinite stack of straight tapes.

AC losses depend on the spatial variation of critical current density.

The model applies to power cables and coated conductor applications.

Abstract

In this paper we develop a method based on the critical state for calculating the current and field distributions and the AC losses in a cable made of curved thin superconducting tapes. The method also includes the possibility of considering spatial variation of the critical current density, which may be the result of the manufacturing process. For example, rare-earth based coated conductors are known to have a decrease of the transport properties in near the edges of the tape: this influences the way current and field penetrate in the sample and, consequently, the AC losses. We demonstrate that curved tapes arranged on a cylindrical former behave as an infinite horizontal stack of straight tapes, and we compare the AC losses in a variety of working conditions, both without and with the lateral dependence of the critical current density. This model and subsequent similar approaches can be of interest for various applications of coated conductors, including power cables and conductor-on-round-core (CORC) cables.