Current limiting performance by single grained Y-Ba-Cu-O superconducting rings

The single-grained YBCO high Tc superconductors (NTS) offer applications in the field of Superconducting Screening Fault Current Limiters (SSFCL) in e lectric power network. The current limiting mechanism is related to the mag netic shielding effect of superconductor. Current limitation can he accompl ished by means of the nonlinear impedance of a transformer with the primary winding carrying the power circuit current and the short-circuited seconda ry winding consisting of rings of single grained Y-Ba-Cu-O (YBCO) material, The latter remains superconductive at normal load level, which art as a ma gnetic nux shielding device to provide low impedance, If a defined current level is exceeded, a sufficient high magnetic flux is generated to penetrat e the HTS ring. The secondary winding turns resistive: and provides a high impedance which limits the prospective fault current. Ring-shaped single gr ained YBCO disks with different thickness and Jc(H) were produced by Top-Se eding Melt-Textured (TSMT) method, The relationship between the superconduc ting properties and the current limiting performance are reported.