Distribution-Connected Electrolyzers with Partial Loading Limit and Power Response Characteristics

This paper investigates the potential of medium-and small-scale hydrogen electrolyzers (HEs) connected to distribution networks to provide essential system support services, including fast frequency response (FFR) and reactive power support. A novel dynamic modeling and control strategy is proposed, featuring a single-stage AC-DC power-electronics interface and incorporating the partial loading limit of electrolysis stack technologies. This limit, imposed due to safety and efficiency concerns, is integrated into the active power reference generation strategy to evaluate its impact on FFR capabilities. Reactive power response modes, including Q mode and V-Q droop control, are also analyzed. Simulation results demonstrate the effectiveness of distribution-connected electrolyzers in delivering FFR and voltage control, while highlighting the constraints imposed by partial loading limits. The findings provide a benchmark for future research on the integration of hydrogen electrolyzers into active distribution networks.