兼顾资源与安全的水库中小洪水优化调度研究：以密云水库为例

Optimized scheduling of medium and small floods in reservoirs considering resources and safety: A case study of Miyun Reservoir

摘要

【目的】密云水库作为京津冀水资源战略储备核心，其现有调度规程在中小洪水应对中存在精细化调控不足、主汛期末水位常低于后汛期水库限制水位的问题，导致蓄水效益受损、水资源动态调控能力有限，难以平衡防洪效益与蓄水效益。为提升水库中小洪水调度的安全性与资源利用效率，有必要进行调度规则的提取与优化。【方法】构建基于模型预测控制(Model Predictive Control, MPC)方法的中小洪水调度模型，针对4个量级的中小洪水，设计11种分级控泄策略调度规则，构建44种情景进行仿真对比，优选出最优调度方案，并对可能最大洪水以及万年一遇洪水进行了模拟分析，验证了模型在极端条件下的适用性。【结果】结果显示：2 a一遇洪水全蓄即可满足需求；5 a一遇洪水最大出库流量从原规则554 m³/s降至244 m³/s,降幅达56%,闸门操作次数从82次降至19次，减少76.8%;10 a一遇洪水、20 a一遇洪水均有不同程度的优化。5 a一遇及以上重现期洪水最大出库流量平均降低25%~30%,末水位稳定在154±0.1 m目标区间，综合评分较原规则提升15%~30%,闸门启闭次数平均减少60%以上。【结论】在遵循现有调度原则的前提下，通过模型的仿真调度，可以实现中小洪水的优化调度，在防洪和兴利间找到平衡点，并有效减轻管理单位的运维成本。研究成果为库容较大且调度分级跨越较大的类似水库应对中小洪水调度优化提供了借鉴。

Abstract

[Objective] Miyun Reservoir, as the core strategic water reserve for the Beijing-Tianjin-Hebei region, has current scheduling rules that exhibit limitations in handling medium and small floods, such as insufficient refined regulation and control, as well as water levels at the end of the main flood season often falling below the reservoir's restricted levels for the post-flood period. This result in compromised storage benefits, and the constrained dynamic regulation capacity of water resources makes it difficult to balance flood control and storage benefits. To enhance both safety and resource utilization efficiency in medium and small flood scheduling, it is necessary to extract and optimize the scheduling rules. [Methods] A scheduling model for medium and small floods based on model predictive control(MPC) was constructed. For four flood magnitudes, 11 graded release strategies were designed as scheduling rules, and 44 scenarios were simulated and compared to identify the optimal scheduling scheme. Additionally, simulations for the probable maximum flood(PMF) and a 10 000-year return period flood were performed to validate the model's applicability under extreme conditions. [Results] The result showed that for a 2-year return period flood, retaining the entire flood volume was sufficient. For a 5-year return period flood, the maximum outflow decreased from 554 m³/s under the original rules to 244 m³/s, representing a reduction of 56%. The number of gate operations decreased from 82 to 19, a reduction of 76.8%. For the 10-year and 20-year return period floods, optimization was achieved to varying degrees. On average, for floods with return periods of 5 years and above, the maximum outflow was reduced by 25%~30%, the final water level stabilized within the target range of 154±0.1 m, the comprehensive evaluation score improved by 15%~30% compared with the original rule, and the number of gate operations decreased by over 60%. [Conclusion] While adhering to existing scheduling principles, optimized scheduling of small and medium floods can be achieved through model-based simulation. This approach strikes a balance between flood control and water utilization, while effectively reducing the operation and maintenance costs for management units. The findings provide a reference for optimizing flood scheduling in similar reservoirs with large storage capacities and significant differences in scheduling tiers.

关键词

中小洪水 / MPC方法 / 调度规则 / 分级控泄 / 蓄泄平衡 / 密云水库 / 预测模型 / 影响因素

Key words

medium and small floods / MPC method / scheduling rules / graded release control / storage-release balance / Miyun Reservoir / prediction model / influencing factors

基金资助

国家自然科学基金项目(U2443207)