The multi-objective and joint operation of Xiluodu cascade and Three Gorges cascade reservoirs system

Abstract

The cascade reservoir system consisting of Xiluodu, Xiangjiaba, the Three Gorges Project and Gezhouba reservoirs is one of the important part of engineering project system which provides the objectives of hydropower generation, flood control and water supply. Therefore, the study on the joint and multi-objective operation of the reservoir system is extreme valuable. A multiobjective model with the objectives of flood control, power generation and water supply is established. We select the power generation as the main objective and use the e -constraint method to convert the other objectives to constraints, thereafter, we solve the corresponding model and obtain the non-inferior solutions set. The flood limited water level of the Three Gorges Project, the minimum required water released are selected, respectively, as the scenario factors of flood control and water supply constraints. The tradeoffs between multiple objectives are analyzed under multiple scenarios. The results show that: (1) when the flood limited water level of the Three Gorges project varies between 146.5 and 153 m, the annual power generation of the entire system can be increased by 7×108 kW h for each 1 meter’s increase in the flood limited water level, and the increased magnitude is the greatest in the wet hydrology years; (2) when the minimum required water released increases by 10%, the annual power generation of the entire system can be decreased by 5×108 kW h; (3) the water supply reliability of the Three Gorges project is more sensitive than that of Xiluodu, and water shortage occurs mainly in the dry season. Moreover, increase in the flood limited water level of the Three Gorges Project cannot resolve the conflict between power generation and water supply during the drawdown season.