A variation of impedance of a high-Tc superconducting fault current limiter with an open core

The high-Tc superconducting fault current limiter (SFCL) is studied worldwide to be classified into a resistive type and an inductive type such as a magnetic shielding type and a DC reactor type. The high-Tc SFCL with an open core belongs to the magnetic shielding type SFCL. Unlike conventional magnetic shielding type SFCLs, it uses the open core to reduce the mechanical vibrations and installed space. The high-Tc SFCL with an open core was designed and manufactured by stacking three BSCCO-2212 tubes and it was tested in the maximum source voltage of 400 Vrms and the results such as the reduction of fault current and impedance of the SFCL are described in this paper. The results show that the fault current in the source voltage of 400 Vrms was reduced to be about 123 A peak and it is about 3.9 times as the normal state current. Also, the impedance of the high-Tc SFCL was about 9 Ω to be about 9 times the normal state impedance. The impedance of the SFCL appears just after the fault, and the size of it is dependent on the source voltage. From the impedance, the inductance of the SFCL was calculated.