Current limiting characteristics of a magnetic shielding type Superconducting Fault Current Limiter of REBCO pancake coils

Superconducting Fault Current Limiters (SFCLs) are installed in the electric power system, and expected to limit fault current and improve system stability. In this paper, we focus on the transformer magnetic shielding type SFCL made of REBCO wires. This SFCL limits fault current mainly with reactance for small fault current. When fault current gets larger, resistance component is added and a larger impedance is generated. In this time, we fabricated the transformer type SFCL composed of pancake coils and investigated the basic characteristics. The pancake coil type has the advantage that the amount of superconducting wire is less and the size of SFCL becomes smaller than solenoid coil type. As the results of experiment, it was confirmed that SFCL limits fault current with reactance and resistance properly. Regarding the current limiting impedance, it almost agreed with the designed value, and confirmed the current limiting operation as expected.