Quench developing process of HTS tapes under sinusoidal over-currents

In power systems, superconducting electric equipments inevitably suffer all kinds of dynamic processes, such as short-circuit fault. Thus they must undergo all kinds of large short-circuit currents, imbalanced currents, which might make superconducting equipments transiting from superconducting state to normal state. In this paper, the over-current faults in power systems are simulated, and a lot of experimental data are obtained, which show quench processes of HTS tapes under sinusoidal over-currents with different amplitudes. Through analysing these data in 2 cycles, the developing processes of normal state in HTS tapes are analyzed and explained. The relations of heat affecting quench developing processes are discussed, and the developing characteristics of normal state in HTS tapes are presented. Firstly, HTS tape under sinusoidal over-currents has better recovery feature when the amplitude of over-current is under two times of the critical current. Secondly, normal resistance develops rapidly as the amplitude of over-current is over three times of the critical current. Finally, quench developing is affected by liquid nitrogen cooling.