Ferromagnetically Shielded Fault Current Limiter (FS‐FCL) Evaluation in Power Line

ABSTRACT This paper presents a novel ferromagnetically shielded fault current limiter (FS‐FCL) configuration and control strategy for power systems. The proposed system introduces a controlled DC‐reactor design that effectively limits fault currents without significantly affecting the system voltage during normal operation. The main novelty of this work lies in the development of a fully ferromagnetically shielded core and the series connection of the FS‐FCL with the power line, which provides an immediate response to fault conditions without delay. In this configuration, the reactor's magnetic flux density is distributed throughout the ferromagnetically shielded core, which increases the effective inductance and prevents magnetic core saturation during fault events. In addition, a control‐oriented model of the FS‐FCL is developed, together with an improved control algorithm based on reference voltage and current thresholds. Both qualitative analyses and quantitative simulations were performed to evaluate the system's transient and steady‐state performance. Simulation results under various fault conditions confirm that the proposed controlled FS‐FCL achieves faster current limitation and lower voltage distortion compared with uncontrolled configurations, demonstrating its feasibility for practical power grid applications.