Combined Optimal Operation Of Reservoir Groups In Yi-shu River Basin

The reservoirs in Yi-shu River Basin are responsible for the flood control safety of Yi-shu River and its surrounding areas.As this area is located in the transition zone between the north and south of China and there are many mountainous rivers in the upstream,the rainfall is extremely unstable,the flood is often sudden and the peak height is large.In history,many flood disasters have occurred,causing huge losses to the local area.In this paper,based on the existing reservoir scheduling rules,flood control scheduling theory and computer technology,an optimal scheduling model is established to make the reservoir group more scientific and reasonable.It is of great significance to alleviate the flood disaster of Yi-shu River and ensure the flood control safety of reservoir and downstream areas.The research work of this paper mainly has the following parts :(1)The geographical location of large reservoirs in Yi-shu River Basin is relatively scattered,and it is difficult to carry out unified joint operation.In this paper,the reservoirs with common flood control tasks are combined,the whole basin is decomposed into four flood control operation systems.A combined optimal operation model of reservoir group peak shifting is constructed with the goal of minimizing the maximum peak flow of the downstream control station section of the reservoir,and the flood control weight β is introduced to limit the peak shifting order of the reservoir.According to the flood process of the control station section,the peak shifting flow and the peak shifting time are set to form a joint scheduling scheme.By continuously reducing the peak shifting flow and prolonging the peak shifting time,multiple sets of joint scheduling schemes are developed for each scheduling model.(2)In this paper,the beta distribution and sine function are introduced into the inertia weight w of the standard particle swarm optimization algorithm,and the inertia weight w is optimized by combining the randomness and dynamic change characteristics of the two.To a certain extent,it can make up for the shortcomings of the algorithm,and improve the search efficiency,population diversity and convergence speed of the algorithm.Taking the rainstorm from July 7 to 9 in 2012 flood season as an example,the combined optimization scheduling model and improved algorithm proposed in this paper are applied to the example calculation.The calculation results show that compared with the single reservoir optimal operation,the combined optimal operation has a more obvious effect on reducing the flood peak flow at the downstream control station and alleviating the downstream flood control pressure.At the same time,the results also verify that the improved particle swarm optimization algorithm has excellent practicability in reservoir(group)optimal operation,and provides a new way for solving the reservoir optimal operation model.(3)Finally,this paper uses the entropy weight-binary fuzzy comparative analysis method to comprehensively analyze and calculate the objective and subjective weights of the evaluation indexes of the maximum discharge,the highest water level,the maximum peak clipping rate and the maximum flood peak flow at the control station during the operation process.The scheme sets of the four combined operation models are evaluated and selected,and the optimal joint operation schemes are selected.Through the combined optimal operation of the reservoir group in Yi-shu River Basin,the flood control capacity of the reservoir group is more rationally utilized,and the flood peak superposition of the main stream flood and the reservoir discharge at the downstream control station is also avoided,which effectively guarantees the flood control safety of the reservoir and the downstream protection area.The research results have certain reference value for the flood control operation in the flood season of Yi-shu River Basin.