Unified optimal operation of Three Gorges and Qingjiang cascade hydropower system

The thesis researches the combined operation of integrated hydropower system which indudes the Three Gorges cascade stations and the Qingjiang cascade stations.To search the unified optimal operation of the integrated system, single and combined optimal operation models of two cascade stations are established.The dynamic programming with successive approximation model is applied to carry out the computation of individual subsystem optimization and optimization of integrated system.The calculation result based on the monthly runoff data from 1951 to 2002 show that the guaranteed output of the unified optimal operation is higher than the sum of two subsystems by 485.5MW.The annual energy output is elevated by 1.69×10~8kW·h if the subsystems has not been involved in the coordinative operation for adjusting the peak load,but it will be greatly elevated by 18.78×10~8kW·h if the subsystems are involved.The benefit is great.Besides,the benefits including the increase of power output in dry season,reduction of the power loss due to surplus water,as well as the improvement of flood control and navigation condition are also attained.