Operational Behaviors of Flux-Coupling Type SFCL Using Integrated Three Phase Transformer Under Transient State

A superconducting fault current limiter (SFCL) has been proposed as an efficient method to protect a power grid from fault current. For applying a SFCL to the power grid, the various ways to increase the capacity of a SFCL should be researched in advance. Thus, the study on SFCL using a transformer has been performed. In this paper, we analyzed operational behaviors of integrated three-phase flux-coupling type SFCL under transient states in the power grid. When single and double line-to-ground fault occurred, all superconducting elements of sound and fault phase were quenched unlike segregated type SFCL. The fault current was limited by mutual supplementing in the all phases. As a result, the limited rate of fault current was small, even though the applied voltage was increased. It means this type SFCL limited the fault current efficiently by sharing of magnetic flux.