Quench Propagation Characteristics of the Liquid Nitrogen Cooled HTS Wires by Externally Injected Heat Energy

With the successful commercialization of Bi-2223 powder-in-tube wire, many attempts to the R & D of the high-Tcsuperconducting (HTS) magnets for high magnetic field applications are now being implemented actively. Although operating temperature of HTS magnet must be kept in the designed level, the magnetic energy and mechanical disturbance can make the operational temperature of HTS magnet unstable. Especially, generated heat energy of inner HTS winding is apt to accumulate, so the normal region appears in HTS winding. This paper deals with the quenching characteristic of reinforced Bi-2223 wire and two bare Bi-2223 wires in adiabatic condition. The minimum quench energy (MQE) of HTS wires was affected by the material and ratio of their matrix. In the same condition, the normal zone propagation (NZP) energy of nonreinforced HTS wire was smaller than that of reinforced HTS wire.