Abstract: For the hydrothermal power system, it presents the optimization method of analyzing the characteristics of interaction among hydroelectric power plants, thermal plants and spatial distribution of the system load to reveal the operation characteristic of hydrothermal power systems and the energy-saving law of power systems. On this basis, a novel optimal scheduling model was constructed to make the water resources best utilized by downstream hydroelectric plants, which can enhance the power output of cascaded hydroelectric plants. An example with cascaded hydroelectric plants and thermal plants was given. The simulation results show that the proposed optimization model can help people to make the best use of the complementary role of hydropower resources, conserving non renewable energy and promoting the sustainable and efficient utilization of energy.

Key words: hydrothermal power systems; cascade hydroelectric plants; interaction characteristic; optimal scheduling