A Multi-stack Power-to-Hydrogen Load Control Framework for the Power Factor-Constrained Integration in Volatile Peak Shaving Conditions

Abstract: Large-scale power-to-hydrogen (P2H) systems formed by multi-stack are potentially powerful peak-shaving resources of power systems. However, due to the research gap in connecting the grid-side performance with the inherent operation control, the continuous operation of P2H loads is limited by the PF assessment under volatile conditions when integrating into the grid. This paper first fills the gap in proposing the analytical models of active and reactive power of P2H loads with a typical power converter interface topology. On this basis, the all-condition PF characteristics of multi-stack P2H loads are captured as functions of unified current and temperature control variables. Then, a PF-constrained multi-timescale control framework is constructed to evaluate flexibility, PF, production, and security comprehensively. A two-level nexus, including a model-based hour-ahead robust model predictive controller and a rule-based real-time increment correction algorithm, is proposed to guarantee the control accuracy and tractability. Case studies verify an intrinsic control tradeoff between PF and production, resulting in an unequal-split allocation strategy compared to the traditional production-oriented control. The significance of the extended PF and security dimensions is verified to improve the flexibility. Furthermore, five typical operating modes respectively corresponding to low, medium, and high load levels at the cluster level are concluded for industrial application.