Research On AC Characteristics Of The High-temperature Coated Superconductor

The construction and development of future grid need multi-disciplinary, multi-angle and multi-level interdisciplinary researches. It also need the application of new technologies and new equipments to accommodate the request of the grid. Superconducting power technology is such a high-tech that is able to meet the requirements and have the economic, strategic significance. High-temperature superconductor (HTS) is being widely used in a variety of applications, therefore the study of AC characteristics of high-temperature superconductors is always a very important area.Based on the systematic introduction of the HTS coated conductors and its research status, this paper studied the AC characteristics of HTS coated conductors by the combination of theoretical calculations, finite element simulation and experimental measurements. The research mainly focued on the frequency dependence and anisotropy of the AC critical current and AC loss of HTS.In the experimental studies, the AC component measurement under self-field and DC applied magnetic field was investigated. And by comparing the advantages and disadvantages of each measurement methods, the AC component measurement platform that can proeside a solid foundation for the research was seted up under the existing condition of laboratory. The experimental results measured by this platform coincided with Norris formula.In the simulation analysis, based on Maxwell’s equations and the E-J exponential characteristics of HTS, the current distribution of YBCO tape was simulated by a finite element model. On this basis, the relationship between AC loss and transport current was studied, and the effectiveness and rationality of this simulation model were verified by the agreement between theoretical and experimental results.In the theoretical analysis, the criterion of AC critical current was given by analyzing the measured AC AC volt-ampere curves of HTS tape. Using this criterion, the frequency dependence of AC critical current under self-field was discovered by the mutual authentication between the experimental measurement and theoretical analysis. What’s more, the impact of the DC applied magnetic field on AC volt-ampere characteristics was investigated, including the influence of field angle on the AC critical current and n value.Finally, the frequency dependence of self-field AC losses caused by eddy current loss was also studied by the comparison between the theoretical and experimental results. The anisotropy of AC loss under DC applied magnetic field was researched as well, which has important significance for the study of the application of HTS.