kA class resistive fault current limiting device development using QMG HTC bulk superconductor

Abstract

kA class HTC bulk superconducting elements of devices for a resistive type fault current limiter for 6 kV distribution networks have been developed and tested. The YBCO devices made with the quench melt growth (QMG) method has 20000 30000 A/cm/sup 2/ critical current densities at 77 K and 1 T determined by the 1 /spl mu/V/cm criterion for the current flow parallel to the a-b plane. The QMG device has 5 /spl mu//spl Omega/-m normal state resistivity and an n-value of approximately 6 for the same direction of current flow. An element of the device with a 1.5/spl times/1.5 mm/sup 2/ cross-section with silver electrodes formed by sputtering could successfully carry exceeding 2200 A/sub peak/ AC transport current in self field at 77 K.