Modeling the Angara-Yenisei Cascade Operations Based on Firm Winter Power Output Maximization

The study explores the current challenges and constraints in regulating the operations of the Angara-Yenisei cascade of hydroelectric power plants. An overview of modern approaches to hydropower plant operation modeling is provided. A mathematical formulation of maximizing of the firm winter power output of the Angara-Yenisei cascade is presented. The developed Garant-Cascade system is described highlighting the interaction of its primary modules. The Angara-Yenisei cascade operations and optimal firm winter power output under various scenarios and constraints were calculated using the Garant-Cascade system. A database of average monthly reservoir inflows for the 1903–2025 period served as the input data for modeling a continuous series of hydropower operating conditions. Two scenarios of the cascade operations with and without firm winter power were discussed. The first scenario involves maintaining the required cascade winter power by regulating discharge at the Bratsk hydropower plant. The second scenario utilizes the dispatch curve to set the discharge of the Bratsk hydropower plant according to the current reservoir water level. The five levels of the winter power (low, reduced, firm, increased, high) were identified depending on the reservoir water level at the beginning of the winter period. The modeling results for the hydropower plant operations during the extreme low-water period of 2014–2018 are presented, demonstrating the minimum cascade winter power.