Research On Multi-objective Optimal Scheduling Of Eco-power Generation In The Lower Reaches Of Lancang River

Hydropower development not only produce social and economic benefits,but also have many adverse effects on river basin ecosystem.How to make best use of the advantages and bypass the disadvantages,improve the comprehensive benefits of reservoir operation,and reduce the adverse impact of hydropower development on watershed ecology is of great significance.This paper selects Nuozhadu-Jinghong-Ganlanba cascade hydropower stations of the lower reaches of the Lancang River as the study area.Firstly,water temperature and flow pulse during spawning period are selected as ecological factors to analyze their spatial and temporal distribution,and study ecological runoff process;then a multi-objective optimal dispatching model of eco-generation for cascade reservoirs is established and solved;finally,the multi-objective non-inferior solution set is evaluated.The main research results are as follows:(1)Based on the daily runoff data at Jinghong,the flow pulse index is selected.The characteristics of the first flow pulse and all flow pulses of the multi-year spawning period(March-September)before the impoundment are studied from the aspects of appearing time,initial rising flow,initial climbing,average climbing,peak flow,duration,annual rate of occurrence,and analyzed the ecological flow schemes in the lower reaches of Lancang River.(2)The vertical water temperature distribution in front of Nuozhadu Dam is simulated by MIKE3 model,and the spatial and temporal distribution law of water temperature stratification in Nuozhadu Reservoir is revealed;The one-dimensional river water temperature model is used to simulate the water temperature distribution along the downstream channel under different working conditions(stop-log gate and bottom outflow),and the superiority of layered water intake of the stop-log gate to improve the discharge temperature is revealed.(3)Three optimal dispatching models of cascade power plants are constructed.Model I takes the maximum annual power generation of cascade as the objective function,and divides two scenarios according to whether the stop-log gate operates or not,and quantifies the influence of the stop-log gate operation on the power generation of cascade power stations.Model ? takes the minimum degree of ecological change as the objective function,and divides two scenarios according to whether or not the discharge pulse during spawning period is considered.The results show that the discharge pulse has an impact on both the ecological change degree and the power generation.Model ? takes the maximum generation capacity and the minimum ecological change as the objective function,takes the water temperature and flow pulse into account,obtains the Pareto curve of cascade generation capacity-ecological change degree in different typical years,and qualitatively analyses the power generation-ecological feedback relationship.(4)The grey relational analysis based on entropy weight method is used to optimize the typical multi-objective schemes of model ?.Based on the evaluation of the optimum schemes of different typical years,the operation schemes of Nuozhadu reservoir in different typical years are recommended.