Electrical and Thermal Characterization of Commercial Superconducting YBCO Coated Conductors

This paper reports on experimental and modeling activities aimed to identify E(I, T) characteristics of commercial YBCO high-temperature superconductor coated conductors (HTS-CCs). The aforesaid approach is applied to investigate the HTS-CCs behavior in the different regimes: superconducting state, flux-creep, flux-flow, and normal state. In order to thoroughly represent the HTS-CCs behavior, parameterized analytical formulations of E(I, T) characteristics have been assumed and then validated through fitting methodologies. Numerical calculation of the electric field as a function of the temperature and of the current density in the HTS-CC, is fundamental to the development of models suitable to design devices based on HTS-CCs. In fact it allows improving the dedicated-software calculation accuracy. This is particularly important for the simulation of superconducting fault current limiter behavior against short-circuits and/or overloads events, because during the superconducting fault current limiter limitation, the HTS-CCs performance strongly depends on the different above-mentioned regimes. As matter of fact, numerical simulations are somewhat simpler for high prospective currents as compared to intermediate conditions as for overload or low short-circuit currents.