Test results of the small model coil for a small-sized superconducting magnetic energy storage device

For the development of the 0.7 MJ small-sized superconducting magnetic ener gy storage (mu SMES) device, we fabricated and tested the small model coil which had parameters similar to those of the optimally designed 0.7 MJ mu S MES device except a stored energy and a device size. The inductance and fie ld measurements indicate that the developed code is applicable to the desig n of the mu SMES devices. The quench test results showed that the highly pr estressed model coil had an excellent de performance in spite of a dry type coil but the quench current decreased to 87 % of the coil's critical curre nt even at the field rate of 0.45 T/s. The quench propagation velocities fo r a kA class superconductor with a NbTi/CuNi/Cu ratio of 1/1/5 ranged from 0.6 m/s to 6 m/s for various operating currents at 4 T.