Regulation-oriented cascade hydropower coordinated operation with pumped storage: dispatch strategy and comprehensive evaluation

Under high-proportion grid integration of variable renewable energy (VRE), challenges arise in the coordinated operation and regulation of conventional hydropower plants (CHPs) and pumped storage plants (PSPs), especially from the perspective of the owners with both CHPs and PSPs. Focusing on active power regulation, a framework to quantify the regulation capability of the hydro-wind-solar-pumped storage hybrid energy system (HWSPHES) from demand, supply, and margin is first established. Then, a model of regulation capability-oriented short-term dispatch (RCOD) strategy is constructed, and a regulation performance evaluation system is established, considering safety, stability, efficiency, and economy. Simulation case study of a real-world HWSPHES base in Central China shows that: (1) Compared to a conventional dispatch strategy mainly focusing on stable operation, the proposed RCOD strategy improves system regulation performance, increasing regulation capability margin by 173.93%, reducing expected energy not supplied by 25.98%, and increasing CHPs regulation mileage by 138.33% on average. (2) Through comparative assessment of different configuration scenarios, the optimal configuration of regulation performance is 4, 4, and 6 PSP units (300 MW each) when VRE capacity is 300%, 400%, and 500% of the cascaded CHPs system in the study area, respectively. (3) With the increase of PSP's scale, the comprehensive performance exhibits a trend of first increasing and then decreasing. This is because the continuous increase in safety and stability is eventually unbalanced by the decrease in economy and efficiency. The proposed framework could improve the coordinated operation level of such systems.