Three-Level Day-Ahead Optimal Scheduling of Power Systems Considering Source-Load Flexibility

To address insufficient peaking capacity from high-proportion renewable energy integration, this paper proposes a three-level optimal power system scheduling method considering source-load flexibility. The upper-level optimizes residual load via an optimal energy curtailment strategy; the middle-level uses demand response to suppress load fluctuations. The lower-level adds thermal storage to traditional thermal units, constructing a modified output model based on thermal storage principles and thermodynamics, while incorporating environmental and cost factors. It optimizes thermal unit output using the CPLEX solver, accounting for pollutant emissions’ impact on economic dispatch under environmental costs. Simulations on a 8-units system show the model achieves economic operation of electrical power system through three hierarchical “peak shaving and valley filling” optimizations, validating its effectiveness in reducing peak-shifting pressure.