Study On Quench Propagation Characteristics Of HTS Tape Under Epoxy Impregnation

In order to improve the stable operation of HTS coils,the quench propagation characteristics of HTS tape under epoxy impregnation were studied in this paper.The quench propagation characteristics of HTS tape under different thickness of epoxy,epoxy materials with different thermal conductivity and different transverse compressive stress were studied in the paper,which provide experimental reference and theoretical basis for the stability of HTS coils and the design of quench protection for HTS coils.At first,this paper briefly introduced the HTS materials and the research progress on quench propagation characteristics at home and abroad,then the significance and main contents of the topic of this paper were extended.And then the paper introduced the critical parameter of superconductor,the basic principle of quench propagation characteristics and the experimental test platform,test platform includes the critical current test system,quench propagation characteristics test system and mechanical performance test system.And the paper expounded the steps of the experiment.All of these provide fundamental of theory and equipment for the test of the paper.Then,the quench propagation characteristics of REBCO tape under different thickness of epoxy were experimentally studied,and the law of quench propagation characteristics was obtained in the paper.By theoretical derivation and formula fitting,the mathematical relations between the quench propagation characteristics and the transmission current and the thickness of epoxy were initially obtained.And the paper analyzed the influence of epoxy impregnation thickness on quench propagation characteristics,it was shown that the increase of epoxy impregnation thickness will reduce the thermal stability of the tape,it was found that 10 mm is the turning point of the degree of influence.And the experimental results were verified by finite element simulation analysis.The experimental results provide theoretical and data support for the stability of HTS coils by epoxy impregnation.And then,the influence of epoxy materials with different thermal conductivity on the quench propagation characteristics of REBCO HTS tape was analyzed by experimental measurements,and the experimental results were verified by combining with finite element simulation analysis,and it was proved that the epoxy impregnated material with high thermal conductivity can more effectively improve the thermal stability of HTS tape,and the law of influence degree of epoxy thermal conductivity on the propagation characteristics of the tape was obtained.It provides experimental reference and theoretical basis for the selection of epoxy impregnating materials for HTS coils.Finally,on the basis of the analysis for the critical current under maximum transverse compressive stress,the quench propagation characteristics of epoxy impregnated REBCO HTS tape under different transverse compressive stress were experimentally studied,and the mathematical relations between the quench propagation characteristics and the transmission current and the transverse compressive stress were initially fitted,it was shown that the increase of transverse compressive stress can improve the thermal stability of the tape.The experiment partly reveals the influence of the pressure on the quench propagation characteristics of the HTS coils.It provides a certain data reference for the design of quench protection.