Quantitative analysis and operation strategies for daily-regulation hydropower plants impacted by upstream plant

Hydropower has rapidly developed as a clean, efficient peaking power source, yet upstream hydropower operations significantly affect downstream inflows, especially for daily-regulated plants with limited reservoir capacity. This necessitates adjustments in their operational strategies. To address this, a research framework is proposed to quantify the impact of upstream operations on daily-regulated plants and develop suitable strategies. Firstly, a flow routing model has been established that is capable of simulating both dynamic wave and diffusion wave propagation in unsteady flow conditions along the river channel. Next, a two-stage short-term peak shaving model is developed that integrates the flow routing model with the peak-shaving operations of hydropower plants. The model incorporates an innovative dynamic control strategy for managing water levels at the start and end of the scheduling period. Finally, the Alpha shapes algorithm is employed to extract operational strategies for daily-regulated hydropower plants. The research conclusions are as follows: (1) New upstream plants can shorten flow routing times between existing cascades; (2) Coordinating peaking times reduces water level fluctuations and boosts downstream power generation; (3) Excessive discharge from upstream plants can limit downstream generation; (4) Tailored peak shaving strategies are essential to adapt downstream operations to upstream impacts.