Measuring transport AC losses in YBCO-coated conductor coils

TLDR

YBCO‑coated conductors are used in AC power applications where superconducting tapes are wound into closely packed coils, causing strong magnetic interactions that alter AC losses compared to isolated tapes and necessitate precise quantification to predict and reduce refrigeration needs. This study experimentally evaluates the transport AC losses in a 25‑turn pancake coil of superconducting tape. The authors employ a detailed measurement technique for AC loss assessment, highlighting specific challenges inherent to this setup. Finite‑element modeling yields preliminary results of the coil’s AC losses.

Abstract

Several AC power applications of YBCO-coated conductors (CCs) involve superconducting tapes wound in coils. In such a configuration the superconducting tape is arranged as closely packed turns, which strongly interact due to the generated magnetic field. This has a strong influence on the AC losses, which are different from those of an isolated tape, and need to be precisely quantified in order to predict and reduce the refrigeration requirements of applications. In this paper we experimentally evaluate the transport AC losses in a pancake coil composed of 25 turns of superconducting tape. We describe in detail the measuring technique utilized, pointing out the issues in this kind of measurement. We also present preliminary results of AC loss computation by finite-element modelling.