Experimental Study of Relationship Between MQE and NZPV With Different Currents on HTS Tapes in a New Simplified Cooling Equipment

Quench is a significant challenge to the operation of high temperature superconducting (HTS) conductors. As an HTS conductor operates at different currents, its quench behaviors may be different. In order to study the quench behaviors of the HTS conductor at different operating currents, in this paper, hot spot-induced quench experiments are performed. In the experiments, to cool the HTS conductor, a simplified cooling device in which the conductor above the liquid nitrogen is able to keep temperature near the temperature of liquid nitrogen is designed. By applying different heat pulses to the conductor to induce quenches, its minimum quench energy (MQE) and normal zone propagation velocity (NZPV) at different operating currents are obtained. The quenches are monitored via voltage changes measured by voltage taps combined with a voltage acquisition system and temperature changes measured by thermocouples combined with a temperature acquisition system. The results show that as current increases from 0.3 Ic to 0.7 Ic, the MQE decreases from 218 J to74 J, but the NZPV increases from 1.85 mm/s to 3.10 mm/s, the changes of these two parameters are nonlinear.