Research On Properties Of Hts Tapes And Coils Carrying Current

As a key technology in the 21st century,Superconducting technology is widely used in superconducting motor, superconducting transformer, supercon-ducting fault current limiter, superconducting cables and other strong electric field.Using Superconducting wire or strip instead of copper in coil can reduce loss and improve current carrying ability. The superconducting material has different characteristic with copper,for example, its carrying capacity will will change with magnetic field and temperature, therefore, it's meaningful to study the current carrying properties of superconducting materials.This paper describes the characteristics of high-temperature superconductors (HTS) critical current and its influence factors,discusses the critical state and the reason of quench,analyses the flux movement of HTS material and E-I properties,presents several common critical current criterion and measures the critical current of the first and second generation HTS tapes under different magnetic field.There is no standard critical current criterion when the HTS tapes works at AC working conditions at present and as to this situation we use anderson-kim flux creep mode to analyse the E-I properties of HTS tapes in AC conditions,discuss the applicability of the critical current criterion,measure the V-I currve of HTS tapes under DC and AC magnetic field carrying DC and AC current.we use electric field criterion and transition criterion to obtain the DC critical current and maximal AC working currentCompared with HTS tapes,HTS coils have lower current carrying capability,it is mainly because that tapes in HTS coils are all under the magnetic field of other tapes and the coil strip will be bent and stretched.Based on the measurement of HTS tapes,we calculate the critical current of HTS tapes with finite element method.Experiment and measurement is important way to study the HTS tapes and coils.we build a measurement platform with labiew program.we present the composition of the experimental system,measurement methods and some key problems.Through compiling the labview program,current can be given automatically It saves the reserchers'Labor intensity and avoids the risk of tapes'burning due to current given too fast.