Experimental Research On Critical Current Characteristics And Stability Of High Temperature Superconducting Tapes

ABSTRACT:The critical current characteristics of HTS tapes are directly related to the design,fabrication and application of HTS power equipment.The composite superconducting tapes have higher current carrying capacity than single superconducting tapes,and can reach kA level.As the most important parameter of the superconductor,the study of the critical current characteristics of the composite strip is very important.The stability of superconducting power equipment is a reliable guarantee for the safe operation of superconducting power equipment.The stability of HTS tape is another important factor to be considered.Therefore,the study on the stability of superconducting tape is also important.In this thesis,the critical currents of different magnetic fields(0T-0.9T)and magnetic field angles(0°?30°?60°?90°)are calculated based on the model of the ReBCO magnetic field.Based on the experimental principle of critical current of HTS tapes under background magnetic field,a critical current testing platform based on LabVIEW was designed and built.The critical current of 5mm wide ReBCO tape was measured at 77K,and the results were compared with the theoretical results.The effect of magnetic field on critical current and n value of HTS tapes is also analyzed.In order to obtain the AC transmission capability of HTS tapes,the volt-ampere characteristics of the 4mm wide AMSC and Superpower HTS tapes under AC condition were measured by analogying the AC loss test method and the definition of critical current.The frequency characteristics of critical current of the two kinds of HTS tapes at 30Hz-540Hz frequency are analyzed by using the rms method and the tangent method.A preliminary experiment and analysis of the current carrying capacity of HTS tape was carried out.The Roebel composite superconducting tape was modeled by Comsol software,and the magnetic field distribution of Roebel composite tape was obtained.The critical current of Roebel composite strip was calculated by using the critical current calculation formula.According to the experimental principle of Roebel composite strip critical current test,the critical current experiment platform of Roebel composite superconducting tape based on LabVIEW was set up.The critical current of Roebel composite superconducting tape was tested.The theoretical results and experimental results were analyzed.In the end,the propagation characteristics of ReBCO tape are analyzed theoretically,and a test system of ReBCO tape based on LabVIEW is designed and constructed.With the aid of this test system,the superconducting properties of ReBCO and Roebel superconducting tapes were tested.The properties of ReBCO tapes and Roebel composite strip,such as the minimum energy loss and the propagation velocity,were obtained and the experimental results are analyze.