Three Gorges Cascade Reservoir Scheduling With Fuzzy Optimization Method

The long-term scheduling of cascade reservoirs is a complex multi-stage, multi-objective decision, playing a great part in reservoir managing. Three gorges cascade reservoirs is a multi-function cascade reservoirs, and plays an important role.in flood control, power generation, irrigation, navigation, and many other aspects. To thoroughly solve this nonlinear constrained and mixed-discrete multiple variables optimization problem, instead of relying on now universal conventional optimization method which cannot bring very good effect, it is necessary to introduce other optimization methods. On the reservoir's optimized operation, long-term runoff forecast influenced by many related factors can't be accurately on each month flow in the future, but can qualitatively determine whether the next year is a high flow year or a low flow year. The highest impoundment level can be regarded as a fuzzy number, which is disturbance around. As the Three Gorges-gezhouba cascade water conservancy hub was designed onMulti-purpose, so during the multi-objective scheduling we may find that the multiple goals are contradictory, some goasl are immeasurable and target weights are obscure. However, we can get a scheduling solution with the actual situation by making better use of these uncertain informations as we apply fuzzy mathematics to the reservoir regulation. On the other hand, as is known to all, a slight ascension of reservoir's upper limit waterlevel will greatly increase the generating capacity.So we can increase the generating capacity by elevating upper limit water level under the guarantee of the dam's safe. In fuzzy scheduling model, the reservoir's highest impoundment level can be regarded as a fuzzy number; can be in design value of around the disturbance, fuzzy scheduling model is superior to the deterministic reservoir scheduling model whose the upper limit water level is fixedConsidering the actual conditions of Three Gorges cascaded hydropower, the model for three gorges and the model for cascade long-term cascade multi-objective scheduling, are established. Corresponding algorithms and programs are coded and added to the three gorges -Gezhouba cascade dispatching decision-making system. At the end of this paper three gorges'historical data is used to demonstrate an example calculation. The two models and their algorithm are typical, one is developed to deal with fuzzy constraint conditions, and the other is developed to deal with fuzzy targets.Due to the conflict between the complexity and the accuracy, the more complex systems will appear more fuzzy phenomena. In order to handle those fuzzy phenomena in mathematical model, it is significant to try a fuzzy optimization method. In this paper, fuzzy constraint conditions of reservoir operation and fuzzy objective functions fuzzed are trial to be handled, which will be the foundation of the further research.