A novel low-impedance bidirectional voltage-clamped fault current limiter based on a coupled inductor

DC faults in DC systems pose severe challenges due to fast current rise rates, high amplitudes, and the absence of natural zero-crossing points. Existing fault current limiters (FCLs) suffer from drawbacks such as fixed impedance affecting dynamic performance, high cost, poor bidirectional current-limiting capability, and reliance on low-temperature refrigeration. To address these issues, a novel bidirectional voltage-clamped fault current limiter based on coupled inductors (BVC-FCL) is proposed. The BVC-FCL utilizes three-winding coupled inductors and bidirectional communication switches (BCS) with metal oxide varistors (MOVs) for voltage clamping. During normal operation, its equivalent inductance approaches zero, minimizing impact on system dynamic performance and reducing on-state losses. When a fault occurs, the coupled inductors switch from parallel to series connection, significantly increasing equivalent inductance, while MOVs clamp the voltage to suppress fault current rise.