Abstract. A novel saturated-cores Fault-Current-Limiter (FCL) configuration is described. This FCL is based on two parallel planes of iron rectangular cores, on which three-phase coils are mounted and connected in series to the grid. Two DC coils are mounted in between the planes on perpendicular core limbs connecting the two AC planes. The DC coils are set to magnetically saturate the AC cores. The transition to three-dimensional, double-storey design enables handling three-phase symmetrical faults while offering better decoupling between the AC and DC circuits. At the same time, it shortens the AC limb lengths and enables deeper magnetic saturation levels in comparison to other saturated cores FCL designs. Hence, this FCL configuration exhibits lower insertion impedance and higher ratio of fault to nominal state impedance in comparison with other designs.        
Simulation results of a laboratory scale model of this FCL design demonstrate that insertion impedance lower than 1% can be easily achieved alongside with fault current clipping larger than 50% for single-phase faults and 30% for three-phase symmetrical faults. These performances meet the demands of most potential installation locations in the grid and therefore make the double-storey FCL design an interesting and promising candidate for future FCL implementation.