Peak Current Limiting Characteristics of Transformer Type Superconducting Fault Current Limiters With Two Non-Isolated Secondary Windings

In this paper, the transformer type superconducting fault current limiter (SFCL) with two nonisolated secondary windings was suggested and its peak fault current limiting characteristics were analyzed. The suggested transformer type SFCL largely consists of two high-TC superconducting elements, one primary winding, and two nonisolated secondary windings, which are wound on the same iron core. Except for the structure with nonisolated secondary winding, the suggested transformer type SFCL has the similar operation to the previously reported transformer type SFCL with two triggering current levels. However, its peak fault current limiting characteristics are different from the previous transformer type SFCL. To confirm its peak fault current limiting operation with two limiting operational currents, the fault current limiting tests of the suggested SFCL according to the fault angle, which affects the amplitude of the initial transient fault current, were performed and its peak fault current limiting characteristics were discussed.