AC Loss Analysis of a Flux-Coupling Type Superconducting Fault Current Limiter

Fault current limiter (FCL) is commonly applied as a current-limiting device to improve the stability of the power system. A flux-coupling type superconducting FCL (FC-SFCL) which mainly consists of a current-limiting unit has been developed. Because of its low steady-state impedance and larger current-limiting impedance at pre-and post-fault, it is regarded as a possible way to restrict fault currents. In this paper, ac loss performances of three structures with different winding methods under three operations were discussed. Then an experimental platform for a small-scale prototype was set up, and several relevant experiments were implemented to test current reduction capacity and loss levels. In theory, the resistive loss obtained by integrating the instantaneous power corresponds to the ac losses of the current-limiting unit. It provides a feasible way to measure ac losses of a magnet, but it needs further verification.