Properties of a prototype Bi-based HTS composite with a high resistivity sheath for resistive fault current limiting applications

Prototype Bi-2223 based composite conductors have been fabricated to provide inherent passive fault current limiting functionality in devices. An HTS insert strand possessing a high resistivity sheath (HRS) was laminated to two metallic strips to provide additional capacity to absorb the heat generated during a fault. Sheath resistivities up to 45 times that of pure Ag were achieved. We summarize the electrical response of 10 to 100 cm straight sections of conductor to pulsed dc and ac currents several times the critical current. DC pulsed I-V characteristics have been obtained over 7 to 8 orders of magnitude of voltage. For electric field levels around 10 V/m, the I-V curves demonstrate the advantage of the HRS conductor in facilitating fault current limiting over the conventional Ag-sheathed Bi-2223 approach. The recovery time for ac faults of 10 Vim was mapped out for various fault hold times. Instantaneous operational recovery was observed for fault hold times up to 3 seconds.