AC transport characteristics of QMG elements for fault current limiting devices

摘要

To study the quenching behavior of a HTSC YBa/sub 2/Cu/sub 3/O/sub 7-/spl sigma// pseudo single crystal bulk superconductor (QMG) as a resistive type fault current limiting device, the E-J characteristics, n-value and propagation velocity of the flux flow state and the resistive state of the QMG elements at 87 K were measured. The n-values, which varied from 5.4 to 7.3 at 87 K, were obtained for the QMG which has 1.6/spl times/10/sup 3/ A/cm/sup 2/ critical current densities at 87 K in 250 G. Based on the heat transfer characteristics between the QMG elements and coolant, the quench propagating velocity of the element in liquid argon is discussed.