基于两阶段风险分析的水库群汛期运行水位动态控制模型

水库(群)实时调度能结合有效的水文预报信息对水库在实时运行层面权衡防洪与兴利效益具有指导意义。然而,水文预报信息的利用面临着不可规避的不确定性问题,故水库(群)实时调度运行需要考虑风险控制方法的研究。针对耦合水文预报的水库群汛期运行水位动态控制问题,提出了可考虑各水库不同预见期长度、不同预报精度的两阶段风险率计算方法,并将其应用于构建水库群汛期运行水位动态控制模型。首先,两阶段风险率思想是将未来调度时段按预见期节点分为预见期以内和预见期以外两个阶段,预见期以内考虑径流预报不确定性带来的风险,采用集合预报思想统计多组预报径流情景在预见期以内的失事概率,预见期以外考虑因预见期末水位过高难于应对后续洪水的潜在风险,根据历史设计洪水的调洪演算试算风险率。其次,基于所提出的两阶段风险率方法构建以发电量最大为目标函数的水库群汛期运行水位动态控制模型。研究结果表明：提出的两阶段风险率计算方法可兼顾考虑实时调度阶段由径流不确定性引起的预见期以内、预见期以外的潜在风险；基于两阶段风险分析构建的水库群优化调度模型,可求解得出的水库群系统库容动态最优决策过程,且该优化调度模型可在不增加汛期防洪风险的基础上提高水库群系统的发电效益,即2010年汉江流域五库系统在夏汛期可提高总发电量2.30亿kWh。

Dynamic Control Model of Multi-reservoir Flood Limited Water Levels During Flood Seasons Based on the Two-stage Flood Risk Analysis

Reservoirs real-time operation can be combined with effective hydrological forecast information, which is of significant guide for the trade-offs between the flood control and utilizable benefit. However, the use of hydrological forecast information is faced with unavoidable uncertainties. Therefore, the flood risk control analysis should be considered in the field of the real-time reservoir operation. A dynamic control model of multi-reservoir flood limited water levels (FLWLs) during flood seasons based on the two-stage flood risk analysis method was proposed to solve the problem that the length and accuracy of forecast period among reservoirs in the system are not match with each other. First, the two-stage flood risk analysis method evaluated the uncertainty of the flood forecasting by dividing the operation horizon into the forecast lead-time and the beyond-forecast time period. The risk within the forecast lead-time induced by the streamflow uncertainty was estimated by counting the frequency of failure numbers among all scenarios with the help of the scenario-based forecasts. The risk beyond the forecast time period caused by the possible high-water level at the end of the forecast period was determined using reservoir flood routing with the design flood hydrographs. A real-time model of multi-reservoir systems was then established by considering the two-stage flood risk analysis method, and the objective of this model was to maxim-