The flux-lock type superconducting fault current limiter (SFCL) connects the two parallel windings in parallel with a ferromagnetic core. We suggest that the double quench flux-lock type SFCL should add a third winding. We analyzed characteristics of the fault current and the peak current using the quench of the high-Tc superconducting element. The proposed SFCL’s inductances of a primary winding and the third winding were fixed and the amplitude of inductance of the secondary winding was changed. We found that the fault current can be more effectively controlled through the analysis of the equivalent circuit and the short-circuit tests.

In this paper, the effect of underpass structure on quality factor and breakdown voltage ofoctagonal inductors which were fabricated with 90 nm complementary metal-oxide-semiconductor (CMOS)technology for radio frequency integrated circuit (RFIC) was studied. It was found that quality factor andbreakdown voltage of inductors with more than one metal layer for underpass showed improvedproperties compared to those with one metal layer. However, little change of quality factor andbreakdown voltage was observed between the inductors with two and more than two metal layers forunderpass. Therefore, underpasses with two metal layers are promising for RFIC designs of the octagonalinductors in 90 nm CMOS technology.

The improved flux-lock type superconducting fault current limiter (SFCL) is composed of a series transformer and superconducting unit of the yttrium-barium-copper-oxide (YBCO) coated conductor. In this paper, we investigated current limiting characteristics through winding direction of coil 2 and variable number of coil 1 and coil 2 in improved flux-lock type SFCL. The better fault current characteristics and the burden of YBCO coated conductor can be confirmed from the experimental result in the higher turn ratio of coil 1 and coil 2 in the additive conditions. In case of subtractive condition, we can confirm a similar result in the same case of experimental conditions. but the burden of YBCO coated conductor has been increased from an increase in winding numbers of coil 2.