Characteristics of an HTS Coil With a Reversely Magnetized Core for the Smart Fault Current Controller

Recently, the smart fault current controller (FCC) was proposed in order to apply to the smart grid. The smart FCC consists of an HTS coil, an AC/DC rectifier, and a control unit. A fault current should be immediately limited by the inductance of the coil at the first peak, and then adjusted by controlling the rectifier. The larger inductance of the coil induces the lower fault current. However, a large inductance coil requires high cost and large size. To reduce the HTS conductor consumption, an HTS coil with a reversely magnetized core (RMC) was proposed. To verify the concept, two permanent magnets were installed. In this paper, various model coils were fabricated and applied to the FCC system: 1) air core, 2) open iron core, 3) closed iron core, 4) open core with RMC, and 5) closed core with RMC. Based on a comparative study on the five models, an HTS coil with a closed RMC has the lowest first peak current. The first peak current in the proposed model was 27.8% smaller than that of air core case. The experimental results show that the proposed concept is to reduce the wire consumption.