Experimental Analysis Of Quench Properties Of YBCO Tape Under Different Arrangement Modes And Defects

In this paper,the experimental is to analyze the MQE(minimum quench energy)and the NZPV(normal zone propagation velocity)of YBCO tape with different arrangement modes and local defects.The main purpose of is to study the thermal stability of superconducting power equipment including superconducting power cables,superconducting transformers and superconducting magnets,and to provide a reference for the quench protection of superconducting devices.According to the experiment require of stacking arrangement,parallel arrangement and twisting strip,the test platform for testing stacked strip and parallel arrangement of strip in liquid nitrogen environment is added on the basis of the test system of the laboratory's quench propagation test.Increase the flow and quench test platform load test twisted strip.The characteristics of the quench propagation including the MQE and NZPV are mainly researched in this paper,the main research contents are as follows:1)In order to study the quench propagation characteristics under different arrangement modes and local defects,the decay of critical current of HTS tape under different tensile strain and bending strain is studied.The defect strip used in this paper is a HTS tape with 70%~75% of critical current attenuation to normal YBCO tape after mechanical strain recovery.It is mainly to simulate the local defects in the tape caused by the superconducting devices in the process of winding and transporting,which will cause the superconducting equipment to quench during the operation of the superconducting equipment,and seriously damage these superconducting devices.2)Firstly,the research on the propagation characteristics of the HTS tape with stacked parallel arrangement is studied,respectively: a)normal superconducting strip and normal superconducting tape stacking;b)normal superconducting strip and defect superconducting tape stacking;c)defective superconducting tape and defective superconducting tape stacking.The propagation characteristics of three kinds of arrangement modes and local defects were studied experimentally.The MQE and NZPV of the stacking strip and its defects are studied experimentally.In this paper,two kinds of quench detection methods,voltage and temperature,are compared.3)The characteristics of the propagation of HTS tape with parallel arrangement are studied: a)normal superconducting tape and normal superconducting tape;b)normal superconducting tape and defective superconducting tape;c)defective superconducting tape and defective superconducting tape.The propagation characteristics of three kinds of arrangement modes and local defects were studied experimentally.4)The equivalent bending diameter of twisted strip on "skeleton" of a certain diameter is calculated by means of equivalent bending diameter calculation.The critical currents in three different equivalent bending diameters are studied experimentally.In this paper,the torsional characteristics of twisted strip are chosen to be twisted "skeleton" with equivalent bending diameter of 11 mm.The failure propagation characteristics of a twisted strip,two stacked twisted strip and two parallel twisted strips were studied respectively in this paper.The research provides support for the thermal stability and safe operation of superconducting equipment.