Hierarchical Control Architecture of Co-located Hybrid Power Plants

The utility-scale co-located hybrid power plants (HPPs) have been receiving attention globally due to enhanced controllability and efficient utilization of electrical infrastructure. While power plant control has been extensively studied for single-technology power plants in the past decades, how to control a co-located HPP that includes sub-plants with multiple technologies is yet to be well defined. To fill the gap, this paper proposes a novel hierarchical control architecture for co-located HPPs. This control architecture contains four control levels: asset control level, plant control level, HPP control level and HPP energy management system (EMS) level. The objective of HPP EMS level is to find optimal strategies for market participation, and the objective of HPP control level is to execute those strategies from the HPP EMS in real time. The interactions across the control hierarchy are firstly discussed in this paper, where attention is closely paid to interactions between HPP EMS level and HPP control level, and between HPP control level and plant control level. Novel strategies for control coordination are presented to ensure all the control levels work together without counteracting against each other. Frequency control and fault ride-through are two examples to demonstrate such control coordination.