Study On DC Impulse,Recovery Characteristics And Energy Dissipation Of High Temperature Superconducting Tape

Superconducting current limiter is one of the indispensable power equipment of flexible DC power grid.As the core component of the superconducting current limiter,the high temperature superconducting(HTS)tape directly affects the current limiting and rapid self-recovery performance of the superconducting current limiter.Studying the DC impulse,recovery characteristics and energy dissipation characteristics of HTS tapes can provide a reference basis for the design of the serial-parallel topology parameters of superconducting current limiters in DC system engineering applications,and the stability of the operation of superconducting current limiters of great significance.In this paper,through the combination of theoretical analysis,macro characterization of experiment and micro research of simulation,the DC impulse and recovery characteristics and energy dissipation characteristics of HTS tapes are studied.Firstly,combined with the basic theory of high temperature superconductivity,the approximate changes of various physical parameters during quenching and recovery of HTS tapes after high current are analyzed,and based on the superconductor critical state model,a description is given to describe the superconducting materials in multiphysics.The E-J-B-T constitutive equation of the relationship among electric,magnetic and thermal parameters.Secondly,according to the experimental principle of impulse and recovery of HTS tapes,an experimental platform was built,impulse and recovery experiments were carried out on HTS tapes,and the experimental results were analyzed,so that the DC impulse and The recovery characteristics are described macroscopically.The change of quenching resistance always lags behind the change of the impulse current.After the current rises to the critical current of the tape,the quenching resistance begins to increase.After the current reaches the amplitude,the quenching resistance increases and the rate of rise of the quenching resistance decreases until it reaches the maximum value.The descent rate,which is significantly higher than the ascent rate,quickly decreases to zero.The change in temperature is a manifestation of heat accumulation.The recovery time ts of the temperature criterion for measuring the stainless steel layer on the surface of the tape is always lagging behind the voltage criterion for directly measuring the superconducting layer of the tape.Finally,based on the multiphysics simulation software of COMSOL Multiphysics,the electro-magnetic-thermal coupling model of the HTS tape is established.The magnetic field restricts the current density and limits the upper and lower limits of the value of the electric field E.The material current distribution is divided into grids,which greatly reduces the amount of calculation.The simulation has obtained the dynamic changes of electrical,magnetic and thermal parameters such as the magnetic flux density,current density,resistivity,temperature and heating power of the HTS tape.The impulse and recovery characteristics of the HTS tape are analyzed based on this and its energy dissipation mechanism was revealed.