A resistive fault current limiter based on high temperature superconductors

Abstract

Abstract A resistive fault current limiter is described that demonstrates the viability of using high-temperature superconducting (HTSC) elements in this type of current limiter design. The primary design issue surrounding such a fault current limiter lies in insuring that the fault energy, manifesting itself as Joule heating in the HTSC elements, is safely dissipated without permanently damaging the HTSC elements. This issue can be resolved by utilizing relatively low I c polycrystalline yttrium barium copper oxide (YBCO) filaments and by placing these filaments in intimate contact with a substantial thermal mass. This thermal mass is provided by a ceramic-filled epoxy composite that, in addition to its thermal properties, contributes substantial mechanical strength to the conductor element. Current limiters based on this design have the advantages of not requiring external fault sensing, an extremely rapid response to fault, and automatic resetting once the fault has cleared.