A Two-Stage Stochastic Optimization for Robust Operation of Multipurpose Reservoirs

Water Resources Management - Robust reservoir operation has long been considered a promising solution for addressing water allocation problems in the absence of reliable hydroclimatic forecasts....     

Reliability Improved Stochastic Dynamic Programming for Reservoir Operation Optimization

Stochastic Dynamic Programming (SDP) is widely used in reservoir operation problems. Besides its advantages, a few drawbacks have leaded many studies to improve its structure. Handling the infeasible conditions and curse of dimensionality are two major challenges in this method. The main goal of this paper is proposing a new method to avoid infeasible conditions and enhance the solution efficiency with new discretization procedure. For this purpose, an optimization module is incorporated into regular SDP structure, so that, near optimal values of state variables are determined based on the available constraints. The new method (RISDP) employs reliability concept to maximize the reservoir releases to satisfy the downstream demands. Applying the proposed technique improves the reservoir operating policies compared to regular SDP policies with the same assumptions of discretization. Simulation of reservoir operation in a real case study indicates about 15% improvement in objective function value and elimination of infeasible conditions by using RISDP operating policies.     

Feasibility Improved Stochastic Dynamic Programming for Optimization of Reservoir Operation

Water Resources Management - Stochastic Dynamic Programming (SDP) is a major method for optimizing reservoir operation. Handling non-linear, non-convex and non-differentiable objective functions...     

Cooperation Search Algorithm for Power Generation Production Operation Optimization of Cascade Hydropower Reservoirs

Water Resources Management - Over the past decades, the reservoirs operation plays an increasingly important role in coping with the serious water, food and energy crisis. However, the curse of...     

The Cascade Reservoirs Multi-Objective Ecological Operation Optimization Considering Different Ecological Flow Demand

Water Resources Management - In order to coordinate the power generation and downstream ecological protection benefits,the optimal ecological scheduling of cascade reservoirs is pivotal. In current...     

水库联合调度供水的探讨

分析水库联合调度的研究现状，针对水库独立供水存在的缺点，根据用水需求提出了水库联合调度供水的方案，通过水库常规调度原则实现两库联合调度的长系列计算，并分析满足供水保证率的前提下提出工程设计规模，实现可充分利用水资源并确定合理工程规模的目标。     

Definition of Risk Indicators for Reservoirs Management Optimization

An alternative procedure for drought risk assessment and for the mitigation of drought risk is proposed in the paper. An analysis of the relationship between failure of water supply systems and reservoir volumes for the urban area of Firenze in central Tuscany, in central Italy, is performed. Long term simulations are carried out using the software package WEAP. A simplified model of the water resources system is built to assess the threshold values and the management rules. The probability to have definite degree of shortage in the water supply system is evaluated in function of the volume stored in the reservoir at the beginning of the month with Monte Carlo simulations. The reservoir levels and volumes are simulated using time series of the period 1970–2005. Four scenarios (i.e. normal, pre-alert, alert and emergency) associated with different levels of severity of drought are defined. Threshold values are identified considering the probability to assure a given fraction of the demand in a certain time horizon, and are calibrated with an optimization method, which try to minimize the water shortages, especially the heavier. The critical situations are assessed month by month in order to evaluate optimal management rules during the year and avoid conditions of total water shortage.     

梯级水库联合优化调度模型及其应用

为充分挖掘梯级水库间的水文补偿和库容补偿潜力,获取更高的综合利用效益,提出应用判别系数与水库蓄供水控制线相结合的方法,并结合免疫粒子群算法,以梯级电站发电量最大为目标,对水库蓄供水控制线进行优化。以乌江梯级水库为例,对其蓄供水方式进行了研究。联合调度结果表明,优化后的水库蓄供水控制线不仅可以合理控制水库蓄放水次序和蓄放水量,达到合理控制水库群运行方式的目的,而且在实际调度中具有良好的可操作性和抗风险性。     

Optimizing Operation Rules of Cascade Reservoirs for Adapting Climate Change

Water Resources Management - Climate change leads to great impact on hydrological cycle and consequently affects water resources management. Historical strategies are no longer applicable under a...     

梯级水库联合优化调度模型及其应用

为充分挖掘梯级水库间的水文补偿和库容补偿潜力,获取更高的综合利用效益,提出应用判别系数与水库蓄供水控制线相结合的方法,并结合免疫粒子群算法,以梯级电站发电量最大为目标,对水库蓄供水控制线进行优化。以乌江梯级水库为例,对其蓄供水方式进行了研究。联合调度结果表明,优化后的水库蓄供水控制线不仅可以合理控制水库蓄放水次序和蓄放水量,达到合理控制水库群运行方式的目的,而且在实际调度中具有良好的可操作性和抗风险性。     

A Triple-stage Operation Method for Deriving Operation Rules for Cascade Reservoirs during Catastrophic Flood Events

Alleviating flood stress and reducing flood disaster losses are vital issues when operating flood control systems. To address catastrophic floods, this study establishes an optimal flood control operation model for minimizing the excess flood volume of downstream flood control points. A triple-stage operation method (TSOM) is proposed to solve the model by dividing flood control operation processes into three stages. The constructed model is applied to the operation of a flood control system located in the middle and lower reaches of the Ganjiang River, China. The results demonstrate that the TSOM has superiority in solving efficiency, reducing excess flood volume by more than 30–230 million cubic meters compared with the progressive optimality algorithm (POA) for most designed floods with 500-year return periods. Furthermore, the discharge and water level processes created by the TSOM fluctuate less than those created by the POA, which meets the requirements of practical flood control operations.

     

Large Scale Reservoirs System Operation Optimization: the Interior Search Algorithm (ISA) Approach

Reservoirs are built to provide a powerful tool to control and manage surface water resources in order to cover inconsistency between water resources and demands. Due to finite available water and the increasing demands for water especially in arid and semi-arid regions like Iran, reservoirs must be optimally operated in order to use water in the most efficient way. This study applies the Interior Search Algorithm (ISA) to solve large scale reservoirs system operation optimization problems. The ISA is a meta-heuristic algorithm inspired from a systematic methodology of architecture process and mirror work utilized by Persian designers for decoration. Unlike other meta-heuristic algorithms, the ISA just have one parameter to tune which is a great advantage. In this study the parameter of the ISA tuned automatically using a linear equation. A real-world one-reservoir operation problem (i.e. Karun-4) and two large scale benchmark problems (i.e. four-reservoir and ten-reservoir operation problem) were employed to show the effectiveness of the ISA. The results shows the high ability of the ISA to solve reservoirs system operation problems as it achieved solutions 99.97, 99.99 and 99.95 % of global optimum for Karun-4 reservoir, four-reservoir and ten-reservoir system operation problems, respectively. These results are the best results reported so far in the studied problems. Comparing results of the ISA with those of non-linear programming (NLP), linear programming (LP), genetic algorithm (GA) and other meta-heuristic algorithms indicates fast convergence to global optimum. Considering the results, it can be stated that the ISA is a powerful tool to optimize complex large scale reservoir system operation problems.     

基于改进调度函数的梯级水库群联合调度研究

梯级水库联合调度规律是指导梯级水库优化运行的重要手段,目前尚无完整的梯级水库群调度规律的理论体系.为此,提出一种可获取梯级水库群联合调度规律的改进调度函数方法,并应用逐步回归法对调度函数进行拟合及相关因子的选择.以乌江流域梯级水库群为例,开展其联合调度研究.结果表明,该方法计算结果较原设计方案,多年平均发电量比设计值增加了14.43亿kW.h,涨幅达5％,保证出力提高到2431.9 MW,经济效益显著.     

新疆山区水库参与调度后平原水库废弃可行性分析

新疆山区水库参与调度后部分平原水库可不再承担原有任务,使平原水库废弃成为可能。以玛纳斯河灌区夹河子水库为例,对比分析夹河子水库废弃前后灌区种植业与水库群联合调度方案的变化,确定平原水库废弃的可行性及对灌区种植业与水库群联合调度等的影响。结果表明:夹河子水库废弃可以降低水库群年蒸发(980.9万~1 884.0万m³)与渗漏(135.7万~878.2万m³)损失;丰水年与平水年增加水库群弃水量(分别增加3 474.4万,1 360.1万m³),枯水年减少弃水量(2 140.1万m³);显著提高灌区种植业产值(30.8%~43.9%)与种植面积(17.4%~29.9%)。故山区水库参与调度后夹河子水库废弃可行,而新疆其他类似地区也可以有选择地废弃部分水深浅、库容小、安全状态差的平原水库。     

一种基于面的三角洲前缘河口坝建模方法

油田深度开发要求建立精细的储层地质模型,为提高模型精度,发展和完善已有建模方法,设计与开发新的建模方法成为储层地质统计学的发展趋势。以荆州长江三角洲前缘河口坝为例,进行了河口坝界面储层建模方法研究。通过观察水槽实验的河口坝形态和不同期次的河口坝单元相互叠置关系,再结合河口坝几何形态数据,建立了河口坝关键界面数学函数。在此基础上,设计了河口坝界面建模算法,并实现了河口坝及其界面空间再现,为后续储层物性建模提供了界面框架。更多还原     

塔里木灌区水库群实时调度研究

为缓和塔里木灌区引水与塔里木河的综合治理这一矛盾,以大系统分解协调技术与动态规划相结合的方法为基础建立了适合本灌区的自适应实时调度模型。为灌区水库实际控制应用提供了理论依据,对塔河的治理具有重要的现实意义。     

西北内陆河流域水库群生态调度模型

针对石羊河流域宏观的水资源配置和调度中的生态问题,探讨了西北内陆河流域水库群生态调度模型的内涵和准则,指出生态调度不仅仅要满足库区及水库下游的河道生态需求,并考虑水库控制的各供水片区的生态环境要求;以单个水库控制的虚拟供水片区作为计算单元进行概化,以供水过程相对均匀为目标函数,以减轻库群建设及运行对生态环境的负面影响为主要约束,建立了石羊河流域水库群生态调度数学模型,并给出具体的模型求解方法和水库群调度方式。     

水库群优化调度中的结构分析方法研究进展

在我国水库群规模日益庞大、功能结构日益复杂化的背景下,结构分析方法在水库群优化调度模型求解中占据越来越重要的地位。为全面梳理不同结构分析方法的适用性和优劣性,以及为复杂结构水库群优化调度提供高效的结构分析方法,基于水库群优化调度60余年来的研究成果,分别阐述了顺序模拟法、蓄供水判别式法、效用均衡理论法、聚合-分解法和水力关联矩阵法5种结构分析方法的研究进展。顺序模拟法逻辑直观、普适性强,蓄供水判别式法能够对发电调度中水库群的蓄供水次序快速排序,以上2种方法均适宜于串联结构水库群结构分析;效用均衡理论基于微观经济学厂商均衡理论对水库群调度方式进行优化,理论基础坚实,适用于水力关系较为独立的并联水库群;聚合-分解法包含水库群联合调度图和大系统分解协调2种形式,可与其他串并联结构分析方法联合使用,适用于大规模混联结构水库群;水力关联矩阵法则采用矩阵形式描述水库群内部两两之间关系,不受水库群结构组合的限制,因此适用于任何结构水库群。结构分析方法对于优化高效求解水库群优化调度问题至关重要,但也需要与其他环节配合才能实现,建议未来在径流预报信息利用、优化调度统计模型与物理背景耦合及混联水库群精细化调度等方向开展进一步研究。     

An Efficient Linearization Method for Long-Term Operation of Cascaded Hydropower Reservoirs

The hydropower reservoir operation is a challenging optimization problem due to the nonlinear factors, where the water head, reservoir storage, release, generating capacity, and water rate are interconnected. To solve such a difficult problem in an efficient and stable way based on mathematical programming, efficient linearization method with high accuracy is of vital importance. This paper simplifies the hydropower output as the function of average reservoir storage and release, and presents an efficient piecewise linearization method that concaves the hydropower output function with a series of planes, which transforms the original nonlinear problem into a linear programming one without introducing any integer variables. The presented method is applied to a long-term hydropower scheduling (LHS) problem with 7 cascaded reservoirs, and a nonlinear direct search procedure is then employed to search further. The performance is compared with that of another linearization method that uses special ordered sets of type two, case study shows that LHS using the presented linearization method runs much faster and obtains results very close to that of the latter one. The presented method, as a high performance exact algorithm, should be very promising in solving the real-world hydropower operation problems.     

施工导流系统随机优化设计

运用设计泄流能力保证率的概念，在考虑水文，水力不确定性的基础上，以围堰挡水隧洞导流方案的研究对，提出了求解施工导流系统费用最小的最优隧洞洞径及围堰高度的随机优化设计方法。