Study on Peak Current Limiting Characteristics of a Flux-lock Type SFCL with Two Magnetically Coupled Circuits

In this paper, we investigated the peak current limiting characteristics of the flux-lock type superconducting fault current limiter (SFCL) with two magnetically coupled circuits. The flux-lock type SFCL with two magnetically coupled circuits has the similar fault current limiting characteristics to the flux-lock type SFCL using its third winding. The current limiting operation of the SFCL is performed by the generation of the magnetic flux between two coils when a fault happens and the fault current limiting characteristics of the SFCL are dependent on the winding direction of two coils. To confirm it, the peak current limiting characteristics of this SFCL were analyzed based on its electrical equivalent circuit and the fault limiting characteristics of this SFCL were investigated through the fault current limiting experiment. Through the analysis on the short-circuit results, it was shown that the limited fault current could be adjusted by the winding direction of two coils.