The Study Of Optimizing Dispatch Method Of Cascade Hydropower Station In Lancang River

The united and optimized operating technology of super-huge basin cascade hydropower stations is not only a pressing need in the new trend of hydroelectric development,but a significant subject which needs to be solved and created.Lancang river basin is one of the thirteen national hydroelectric basements,which has abundant hydropower resource and great potential to be developed.According to National Review Results of Hydropower Resource,technical available capability of Lancang river basin inside Yunnan is410749.2 ? MW MW,and economic available capability is 410558.2 ? MW,which have leapt into the front ranks of China.In addition,according to the actual review results of the basin,economic available capability of the mainstream is about41044.2 ? MW,which accounts for 25% of the whole economic available capability in Yunnan Province.According to Lancang river hydroelectric planning achievements and prophase working condition,the main stream of Lancang river inside Yunnan will form the special “two reservoirs and six steps” cascade hydropower stations in 2015,which regards the hydropower stations in Xiao Wan and Nuo Zhadu as regulating reservoirs,and form “three reservoirs and fourteen steps” cascade hydropower stations in 2020,which treats Gu Shui,Xiao Wan and Nuo Zhadu as regulating reservoirs.The cascade hydropower stations in the main stream of Lancang river have two fundamental advantages,one is on a large scale,the other has a wide range of power transmission.The dispatchers of the mainstream cascade hydropower stations will face a series of difficult problems,such as the handling of constraint conditions,the construction of objective function,the coordination between the results of computing theory of engineering model and engineering reality,and the increasing of engineering uncertain factors.Therefore,with those challenges,the related studying results show that the breakthrough progress in both theory and practice has great influence in hydroelectric field.On the other hand,the engineering management operation has not only an effect on engineering benefits,but also relates to flood discharging,ecological stabilization,hydrology characteristics,urban water supply of the two sides of mainstream in Lancang river.Besides,it has an in fluence on the distribution of power grid and steady operation in the basin.In Lancang river basin,the problem of united dispatching of the optimized cascade hydropower station is not only related to efficient and secure operation of hydropower station,but also associated with the implementation of sustainable development of water resource utilization.After engineering construction,it will realize the safe and steady operation,engineering benefit and hydrology,power,and estimated compensation of capacity loss.After completely finishing building Nuo Zhadu hydropower station,the operation work of associated dispatching of super-huge basin cascade hydropower stations will be fully launched.The dispatching operation of such large-scale cascade hydropower stations involves many fields,which has great difficulties.It is a precedent both at home and abroad.As a result,the research project of the united dispatching operation of super-huge basin cascade hydropower station is not only a significant practical demand of river developer,but a great scientific research problem and research interests in the trend of hydropower development in China.It is also a creative subject in hydropower industry both at home and abroad.In fact,the main topic in this thesis is not a new issue appeared recently.According to different methods of classification,models can be divided into many types.If mainly considered different runoff descriptive ways,long-term dispatch model can be divided into stochastic model and deterministic model.Stochastic model uses the random process to describe reservoir inflow;deterministic model uses determining process to describe it.Those two methods use stochastic and deterministic process to describe reservoir inflow.Deterministic model generally bases on historical runoff data,weather forecast data and other information to get the results.Generally speaking,in the process of simulating several reservoirs optimized dispatching,because of the uncertainty of economy and hydrology which is related to reservoirs form stochastic results,thus the process of optimized dispatching is the process of optimized control which bases on stochastic results.Accordingly,stochastic models are more specific and meaningful for those uncertain fa ctors in terms of utility.However,in the stochastic models,natural runoff data uses multi-year frequency distribution model.It usually uses the expectation of number sequence to show the right result which has the average meaning of multi-year runoff.Thus,the optimum may be larger in dry year,and it may be smaller in other years.In terms of practical operation,deterministic method is much better.How to combine two methods effectively,and make the most of stochastic and deterministic method,is a significant subject both theoretically and practically.Therefore,the special research about how to optimize the dispatching in cascade hydropower station in Lancang river,is a practical need of secure management and efficient operation in the optimized dispatch system of cascade hydropower station.It is also a need which improves the utilization efficiency of water resource in Lancang river.The research in this thesis will provide some meaningful references to those optimized dispatching method of large-scale and wide transmission cascade hydropower station.