AC Losses Measurement and Analysis for a 2G YBCO Coil in Metallic Containment Vessels

AC losses in high-temperature superconductors are an important design parameter for large-scale power applications. It is often necessary to have a metallic containment vessel to house the superconducting element in a closed-loop cryogenic system. This, however, produces additional ac losses due to induced eddy currents in the walls of the vessel. This paper focuses on the investigation and understanding of the induced eddy current loss in the containment vessel. The total ac losses of a 1-m yttrium barium copper oxide coil were experimentally measured in three different containment vessels. The predicted eddy current loss from finite-element modeling combined with the measured superconductor hysteresis loss demonstrated good agreement with the experimental results. This paper also includes the implications for practical design of commercial cryostat containment vessel for superconductor power applications to minimize ac losses.