The characteristics of the normal transition in the longitudinal and transverse directions in cryocooled YBCO coils

Recently, the superconducting devices using cryogenic and superconducting technologies were widespread in the field of electric power. The 2G wires with YBCO superconducting layer, metal substrate and stabilizer layer are expected to be used in future superconducting applications, because it has high J _c properties in high temperature and high magnetic fields. In order to operate safely at high transport currents, the thermal stability of the wounding wire should be addressed in terms of detection and protection against the quench. On the other hand, the understanding of the 3-dimensional normal zone expansion during a quench is very important to design the superconducting devices such as magnets and cables. This paper presents the results of an experimental study for normal zone propagation properties in the longitudinal and transverse directions using the pancake coil wound with 2G wires which have Cu and SUS stabilizers under the cryocooler cooling. And the minimum quench energy (MQE) of the pancake coils wound with two different kinds of stabilizers as functions of operating temperature and transport current will be described.