| Flood disaster has brought incalculable losses to our country,which has become a major problem restricting china's economic and social development.At the same time,due to the uneven distribution of rainfall time and space in China,many areas of water resources are seriously short,can not meet the "three-life" water demand.Therefore,how to prevent and control floods at the same time make full use of flood resources is an important topic in china's water research,but also China's focus on the difficult problem.With the improvement of science and technology,forecast information is gradually applied to reservoir dispatch research,improve the utilization rate of flood resources,alleviate the problem of insufficient water resources supply.In recent years,the research on reservoir scheduling theory and method based on forecast information has made rich and innovative results,but because of the existence of the error of forecast information and the deviation of the understanding of reservoir scheduling risk affected by the error,the results have not been widely used in reservoir scheduling practice.In order to better popularize the research results in the practice of scheduling,it is necessary to clarify the ability of reservoir system to resolve forecast errors in the process of runoff regulation,as well as the transmission and transformation process of the risk of upstream and downstream flood control objects in the process of reservoir scheduling.In view of the above problems,this paper takes the control reservoir group-Qing-Chai multi-reservoirs and Dahuofang reservoir as the research background,carries on the research on the prediction and dispatch of reservoir flood control and the characteristics of the dynamic change of risk.Firstly,based on the research results of the forecast error distribution,this paper analyzes the change severity of the reservoir flood control dispatch index under different water levels,studies and determines the limit water level control area that takes into account the forecast error,secondly,analyzes the process of the prediction error in the reservoir scheduling process and its conduction characteristics of the flood control risk in the upper and lower reaches of the reservoir.The main research content and results are as follows:(1)The study determined the reservoir limit water limit control area under the condition of forecast error.Firstly,the risk source of reservoir forecast ingress and dispatch,that is,select the net rain forecast error and the starting water level as the risk factor,and secondly,based on the existing reservoir forecast and dispatch rules,analyzes the acceptable error field of reservoir flood prediction and dispatch by adjusting and calculating the different frequency floods,and the analysis results show that the acceptable forecast error area is larger than the forecast error area of the great entropy calculation.Although the risk is still in a controlled state,but the flood control control index value has a large mutation,and the impact of the water level on the flood control dispatch index is greater,and finally,the comprehensive above analysis and calculation results determine the limit water level control domain that takes into account the forecast error,for the single library,after considering the limit forecast error,the limit water level control domain has narrowed.(2)The dynamic change characteristics of reservoir flood prediction and dispatch risk are studied.In view of the problem that the prediction information error elimination process is not clear in reservoir flood control dispatch,and the dynamic characteristics of the change of forecast ingress risk are not described enough,the paper analyzes the changes of various flood control indicators in the process of regulation and calculation of different frequency floods from the aspects of large and small flood forecast errors.When the forecast error is large,the reservoir obtains accumulated net rain information,increases the pre-drain,frees up the flood control reservoir capacity,does not increase the flood control risk of the reservoir itself,because of the increase of the pre-drain flow,makes the first half of the downstream combined flow slightly increased,the risk is passed from upstream to the downstream flood control target,but at this time the interval flood flow is small,will not increase the downstream flood risk;It will not increase the flood prevention risk of the reservoir itself,and the forecast rules to the reservoir water level as an auxiliary indicator,but also to a certain extent to avoid the risk of the forecast is too small,when the error is too large,the reservoir will increase the leakage or even open,at this time the risk is passed to the downstream flood control target.(3)The rules for optimizing flood control in parallel reservoir groups taking into account forecast errors are formulated.Firstly,based on the rules of flood prediction and dispatching of the original reservoir group and the acceptable domain of single-library forecast error,the research and analysis of the dynamic control domain of the limit water level of each reservoir in the reservoir group joint flood prediction and dispatch,the results show that the dynamic control domain of the limit water level of the reservoir group is enlarged compared to the single-library flood prediction and dispatch,and the error area of acceptable flood forecast is slightly reduced;Using NSGA algorithm to solve the joint scheduling model,the reservoir group scheduling rules are optimized,and the results show that the optimization rules raise the water level of the Qing and Chaihe reservoirs,the water level of the Qinghe reservoir from 128 m to 129.05 m,and the water level of the Chaihe reservoir from 105.2m to 106.4m.Therefore,the new rules for optimizing flood control scheduling in parallel reservoir groups are formulated to increase the benefit of the flood control in the flood control of each reservoir and downstream flood control targets without increasing risk. |
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