Bi-2223 and Bi-2212 tubes for small fault current limiters

The superconducting fault current limiters (SFCL) can be used to limit the short-circuit current level in electrical transmission and distribution networks. In one concept of SFCL-serial resistive limiter, the superconductor is inserted in the circuit directly. During a fault, the fault current pushes the superconductor into a resistive state and resistance, which limits the fault current, appears in the circuit. Another concept-inductive limiter works like transformer with shorted superconducting secondary winding. The impedance of this limiter under standard operation conditions is nearly zero, since the zero impedance of the secondary superconducting winding is reflected to the primary. In the event of a fault, the resistance in the secondary winding is reflected into the circuit and limits the fault current. The small inductive type SFCL´s with Bi-2223 tubes with critical current=112 A, 625 A, and 1210 A (at 77 K and self-magnetic field) and various numbers of primary winding turns are presented with their limitation coefficients. The resistive type SFCL based on Bi-2212 tube with critical current=125 A (at 77 K and self-magnetic field) is presented too.