大中型水库防洪调度常见问题分析及对策研究

一、水库调度大中型水库一般属于综合利用水库,通过实施防洪调度和兴利调度,实现防洪、供水、发电、航运及改善河湖生态等综合利用效益,是保障我国防洪安全、供水安全、粮食安全,满足人民群众美好生活需要的重要基础设施。水库防洪调度是运用水库挡水建筑物和泄水建筑物,有计划地实施洪水拦蓄或安排下泄,以达到防洪减灾和蓄水兴利最优效果的调度过程,是综合利用水库调度的重要内容。     

基于动态规划的紫坪铺水库发电优化调度模型研究

紫坪铺水库是我国特大型都江堰灌区的水源工程,担负着成都、德阳、绵阳等7市37县(区)综合供水和成都地区的防洪任务,兼有发电、生态环境保护等综合效益,直接受益人口2600多万人,是我国西部大开发首批十大标志性工程之一。针对紫坪铺水库发电优化调度问题,按照实际调度情况,运用动态规划算法,建立了以防洪、供水、工程安全运行为约束条件,以发电效益最优为目标函数的紫坪铺水库发电优化调度模型,模型可为紫坪铺水库发电优化调度提供决策依据。     

综合利用水库优化调度

综合利用水库涉及防洪、发电、灌溉和航运等多个水资源管理利用部门,实现水库优化调度较为复杂。目前国内对单一发电水库的优化调度研究较多,方法也较成熟,而对综合利用水库的优化调度研究甚少。本文在单目标发电水库优化调度的基础上,对综合利用水库优化调度进行了有益的探索,并有所创新,在丹江口综合利用水库优化调度研究中,取得了较为满意的效果。     

基于人工遗传算法的阿尔塔什水库优化调度研究

为制定阿尔塔什水库调度方案,以灌溉缺水量最小为目标建立了兼顾流域灌溉、生态、发电、防洪等多目标的优化调度模型,并采用GA算法求解模型。结果表明：调度结果不满意,灌溉保证率未满足设计要求,水库发电量远低于设计21.86亿kW·h的目标;下泄塔河生态水量满足下泄9.71亿m³目标,但保证率过低,缺水年份破坏深度过大;制定了阿尔塔什水库的水库调度图。研究成果对充分发挥阿尔塔什综合利用功能、保障流域各项综合利用要求具有重要指导作用。     

梅山水库调度方式浅析

根据梅山水库工程特性,依据国家及相关部门批准的梅山水库设计文件,对水库运行条件进行分析,明确了水库防洪、灌溉、发电及生态用水调度的原则和方式,进一步规范了大型水库调度规程,为综合利用工程优化调度提供借鉴。     

皂市水库生态友好型优化调度

以水电站年发电量最大为优化目标,以满足由逐月频率法计算的水库下游适宜生态流量下限为约束条件,构建皂市水库生态友好型优化调度模型,并利用该模型选取典型年,采用动态规划法进行皂市水库常规调度与优化调度的发电效益对比以及优化调度与生态优化调度的发电效益对比研究。结果表明,总体平均而言,皂市水库优化调度比常规调度年发电量可增加1.8%,基于保障下游河段生态径流过程的皂市水库生态优化调度比优化调度年发电量减少0.95%。     

允许风险约束下水库洪水资源化研究

为了实现洪水资源化,把风险概念引入到防洪调度中,在汛期允许风险约束下,建立了汛期综合利用水库洪水资源化调度模型。该调度模型不仅兼顾水库的防洪安全,而且使汛末水库尽可能的多蓄水,有利于洪水资源化。算例分析表明,该模型可以有效地协调防洪与兴利之间的矛盾。     

基于状态转移矩阵的梯级水库优化调度确定性离散动态规划方法

基于状态转移矩阵的确定性离散动态规划(DDDP)方法是在考虑水库运行的综合利用的前提下,利用状态转移矩阵寻找出梯级水库优化调度过程中所有的可行策略,基于目标函数逆向搜索可行策略,得出最优解的优化算法.该方法可进行单库优化计算,也可以进行梯级水电站优化计算.文中以锦屏梯级为例,说明该方法可在满足梯级水库上下游生态用水、发电用水等综合利用的前提下,以梯级水电站发电效益最大为目标,求得梯级水库优化调度的较好解.     

供水水库优化模拟风险调度模式的研究

针对水库调度过程中的风险问题,引入了供水水库调度的优化模拟风险管理模式.首先建立了供水水库群的优化调度模型,然后对度量风险的可靠性、脆弱性、回弹性、事故周期等指标作了论述.在此基础上,模拟水库调度过程中存在的风险,并通过模拟与优化的反馈机制,建立了供水水库优化模拟风险调度的总体模式.     

柘溪水库防洪发电优化调度策略研究

柘溪水电站地处湖南中部的资水流域,在湖南省承担重要的防洪及发电任务。近年来受全球气候变化影响,暴雨事件频发,导致水库发生弃水,甚至威胁下游防洪安全。当前在柘溪水库流域暴雨预测、水库入库流量和水位预测等方面开展了一些研究工作,但尚未形成完整的柘溪水库防洪发电优化调度体系。提出了柘溪水库防洪发电优化调度策略,涵盖水库流域暴雨长期形势分析、暴雨位置与强度预测、分布式产汇流计算、防洪发电多目标调度方案制定等方面,可为柘溪水库防洪发电优化调度提供技术支撑。     

Optimization and risk analyses for rule curves of reservoir operation: application to Tien-Hua-Hu Reservoir in Taiwan.

Tien-Hua-Hu Reservoir is currently under planning by the Water Resources Agency, Taiwan to meet the increasing water demands of central Taiwan arising from rapid growth of domestic water supply, and high-tech industrial parks. This study develops a simulation model for the ten-day period reservoir operation to calculate the ten-day water shortage index under varying rule curves. A genetic algorithm is coupled to the simulation model to find the optimal rule curves using the minimum ten-day water shortage index as an objective function. This study generates many sets of synthetic streamflows for risk, reliability, resiliency, and vulnerability analyses of reservoir operation. ARMA and disaggregation models are developed and applied to the synthetic streamflow generation. The optimal rule curves obtained from this study perform better in the ten-day shortage index when compared to the originally designed rule curves from a previous study. The optimal rule curves are also superior to the originally designed rule curves in terms of vulnerability. However, in terms of reliability and resiliency, the optimal rule curves are inferior to the those originally designed. Results from this study have provided in general a set of improved rule curves for operation of the Tien-Hua-Hu Reservoir. Furthermore, results from reliability, resiliency and vulnerability analyses offer much useful information for decision making in reservoir operation.     

Optimisation of Multiple Hydropower Reservoir Operation Using Artificial Bee Colony Algorithm

In this study, the Artificial Bee Colony (ABC) algorithm was developed to solve the Chenderoh Reservoir operation optimisation problem which located in the state of Perak, Malaysia. The proposed algorithm aimed to minimise the water deficit in the operating system and examine its performance impact based on monthly and weekly data input. Due to its capability to identify different possible events occurring in the reservoir, the ABC algorithm provides promising and comparable solutions for optimum release curves. The optimal release curves were then used to stimulate the reservoir release under different operating times under different inflow scenarios. To investigate the performance of both the monthly and weekly ABC optimisation employed in the reservoir, the well-known reliability, resilience and vulnerability indices were used for performance assessment. The indices tests revealed that weekly ABC optimisation outperformed in terms of reliability and vulnerability leading to the development of a better release policy for optimal operation.     

Evaluation of Real-Time Operation Rules in Reservoir Systems Operation

Reservoir operation rules are logical or mathematical equations that take into account system variables to calculate water release from a reservoir based on inflow and storage volume values. In fact, previous experiences of the system are used to balance reservoir system parameters in each operational period. Commonly, reservoir operation rules have been considered to be linear decision rules (LDRs) and constant coefficients developed by using various optimization procedures. This paper addresses the application of real-time operation rules on a reservoir system whose purpose is to supply total downstream demand. Those rules include standard operation policy (SOP), stochastic dynamic programming (SDP), LDR, and nonlinear decision rule (NLDR) with various orders of inflow and reservoir storage volume. Also, a multi-attribute decision method, elimination and choice expressing reality (ELECTRE)-I, with a combination of indices, objective functions, and reservoir performance criteria (reliability, resiliency, and vulnerability) are used to rank the aforementioned rules. The ranking method employs two combinations of indices: (1) performance criteria and (2) objective function and performance criteria by using the same weights for all criteria. Results show that the NLDR gives an appropriate rule for real-time operation. Moreover, NLDR validation is presented by testing predefined curves for dry, normal, and wet years.     

Performance Risk Analysis for Fukuoka Water Supply System

In this study, simulation is used to evaluate the performance of the municipal water system in Fukuoka city. In combination with daily simulation model, a kind of risk model incorporating water demand prediction is presented. This model applies five risk indices: reliability, resiliency, vulnerability, drought risk index (DRI) and drought damage index (DDI). They aid in the identification of operation policies for the municipal water system, and the planning and operational policies obtained are aimed at achieving minimum risk for a given scenario of operation. In this paper, the performance risk of the municipal water system is investigated under three alternatives: (1) the existing system operation when available supply from the Chikugo river is decreased; (2) water restrictions for different percentages of reduction are implemented; and (3) available water supply increases when desalination of sea water is implemented. The results obtained show that savings of between 5 and 12% of water consumption from May 1, or increasing of daily desalination of sea water about 30 000 m³ or more, may efficiently decrease the performance risk of the Fukuoka water supply system. Potentials also exist for further increase of reservoir storage by more rational operation. The measure that more attention should be paid to increasing the water supply from stable sources is recommended as well.     

Sustainability Assessment of Urban Water Distribution Systems

A methodology is presented for determining sustainability indices for pressure and water age in water distribution systems (WDSs). These sustainability indices are based upon performance criteria including reliability, resiliency, and vulnerability. Pressure and water age are determined for a WDS as a function of operation time using the U.S. Environmental Protection Agency EPANET model. The values of pressure and water age are used to determine reliability, resiliency, and vulnerability performance criteria, which are then combined into the nodal sustainability indices for water age and pressure. In addition, the sustainability index (SI) computations are performed for zones to define the SI for water age and SI for pressure. A combined SI calculation is performed to produce an overall sustainability score for the entire zone in the water distribution network. The proposed methodology can be used to monitor the sustainability of existing WDSs and to help define alternative solutions including changes in pump operation and modifications to WDS to increase the sustainability.     

Development of an Optimal Reservoir Operation Scheme Using Extended Evolutionary Computing Algorithms Based on Conflict Resolution Approach: A Case Study

Optimal reservoir operation and water allocation are critical issues in sustainable water resource management due to increasing water demand. Multiplicity of stockholders with different objectives and utilities makes reservoir operation a complicated problem with a variety of constraints and objectives to be considered. In this case, the conflict resolution models can be efficiently used to determine the optimal water allocation scheme considering the utility and relative authority of different stakeholders. In this study, the Nash product is used for formulation of the objective function of a reservoir water allocation model. The Analytic Hierarchy Process (AHP) is used to determine the importance of each stockholder in bargaining for water. The Particle Swarm Optimization algorithm (PSO) and the Imperialism Competitive Algorithm (ICA) are applied to solve the proposed optimization model. System performance indices including reliability, resiliency and vulnerability are used to evaluate the performance of optimization algorithms. The simplest and most often-used reservoir policy (Standard Operating Policy, SOP) is also used in order to evaluate the performance of the proposed models. The proposed model is applied to the Karkheh River-Reservoir system located in south western part of Iran as a case study. Results show the significance of the application of conflict resolution models, such as the Nash theory and proposed optimization algorithms, for water allocation in the regional scale especially in complicated water supply systems.     

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.     

Optimization of Exclusive Release Policies for Hydropower Reservoir Operation by Using Genetic Algorithm

The efficient utilization of hydropower resources play an important role in the economic sector of power systems, where the hydroelectric plants constitute a significant portion of the installed capacity. Determination of daily optimal hydroelectric generation scheduling is a crucial task in water resource management. By utilizing the limited water resource, the purpose of hydroelectric generation scheduling is to specify the amount of water releases from a reservoir in order to produce maximum power, while the various physical and operational constraints are satisfied. Hence, new forms of release policies namely, BSOPHP, CSOPHP, and SHPHP are proposed and tested in this research. These policies could only use in hydropower reservoir systems. Meanwhile, to determine the optimal operation of each policy, real coded genetic algorithm is applied as an optimization technique and maximizing the total power generation over the operational periods is chosen as an objective function. The developed models have been applied to the Cameron Highland hydropower system, Malaysia. The results declared that by using optimal release policies, the output of power generation is increased, while these policies also increase the stability of reservoir system. In order to compare the efficiency of these policies, some reservoir performance indices such as reliability, resilience, vulnerability, and sustainability are used. The results demonstrated that SHPHP policy had the highest performance among the tested release policies.     

Optimizing Reservoir Operation Policy Using Chance Constraint Nonlinear Programming for Koga Irrigation Dam,Ethiopia

One of typical problems in water resources system modeling is derivation of optimal operating policy for reservoir to ensure water is used more efficiently. This paper introduces optimization analysis to determine monthly reservoir operating policies for five scenarios of predetermined cropping patterns for Koga irrigation scheme, Ethiopia. The objective function of the model was set to minimize the sum of squared deviation (SSD) from the desired targeted supply. Reservoir operation under different water availability and thresholds of irrigation demands has been analyzed by running a chance constraint nonlinear programming model based on uncertain inflow data. The model was optimized using Microsoft Excel Solver. The lowest SSD and vulnerability, and the highest volumetric reliability were gained at irrigation deficit thresholds of 20 % under scenario I, 30 % under scenario II, III and V, and at 40 % under scenario IV when compensation release is permitted for downstream environment. These thresholds of deficits could be reduced by 10 % for all scenarios if compensation release is not permitted. In conclusion the reservoir water is not sufficient enough to meet 100 % irrigation demand for design command areas of 7,000 ha. The developed model could be used for real time reservoir operation decision making for similar reservoir irrigation systems. In this specific case study system, attempt should be made to evaluate the technical performance of the scheme and introduce a regulated deficit irrigation application.     

An Objective Multi-Criteria Evaluation of Water Management Scenarios

Advanced computer models are commonly used to simulate reservoir system's performance. If the number of possible management scenarios is large, it can be extremely difficult to follow related system's operation and get a valuable picture on its spatial and temporal behavior. The decision maker or analyst can be overburdened by quantity and complexity of information generated by model, particularly if system operation is repeatedly simulated for multiyear periods. Related problem is how to select the scenario with most desired long-term consequences. Possible approach is to use selected parts of model's output and re-interpret system behavior by means of certain performance indicators, create appropriate decision matrix and perform multi-criteria analysis to rank decision alternatives (scenarios). The paper proposes a methodology that includes: (1) multiyear simulations of system operation; (2) computing spatially and temporally distributed systemperformance indices such as supply reliability, resiliency and vulnerability; (3) unbiased entropy-based weighting the importance ofperformance indices; and (4) final ranking of scenarios by means of multi-criteria analysis. The number of scenarios and number of performance indices is not restricted, and to account for possibly large sets of scenarios, an ideal-point-distance multi-criteria method TOPSIS is suggested. Proposed methodology appeared to be confident and robust in proof-of-concept application in Brazil.