Superconducting Cables Characterization with an electrical method

TL;DR

This paper investigates the impact of electromagnetic skin currents on electrical AC loss measurements in superconducting tapes, proposing optimized circuit configurations to minimize measurement errors for accurate loss estimation.

Contribution

It introduces a systematic analysis of skin current effects on superconducting tape loss measurements and proposes measurement circuit configurations to reduce these errors.

Findings

Skin currents cause systematic errors in loss measurements.

Optimized circuit configurations can minimize skin current effects.

Electrical method accuracy depends on circuit design to account for electromagnetic effects.

Abstract

AC losses in High Temperature Superconductor tapes (HTS) are an important design parameter for large scale power applications. The electrical method is often used for losses measurements on SC tapes and, when the results are to be compared to computed estimations, simple theoretical models like the Norris Brandt are typically used. Electromagnetic dynamic effects are not usually taken into account by the simpler models, but their presence may corrupt the measured data. In this paper, a preliminary study on a conventional copper bar sample has been done to evaluate the effect of the skin currents on the specimen losses measures obtained from the electrical method. The measurement procedure has afterward been applied to a SC YBCO tape (Superpower SCS4050AP), obtaining circuit configuration dependent results. Because the SC losses must obviously be measurement circuit independent, a systematic error due to the skin currents must be playing a role. The skin current induced error is always there and, in order to apply the electrical method for losses estimation, the only possibility is its minimization. The best choice for the measurement circuit to be adopted, in order to minimize the skin current undesired contribution, will finally be proposed.