A hybrid analytic/rule-based approach to reservoir system management during flood

The article presents an approach to real-time operation of a water retention reservoir during flood. Water releases are calculated repetitively on the basis of two-variant inflow forecasts and some expert knowledge. During every intervention of the control algorithm, an optimization problem with the expected value type performance index is solved. In the paper, the basic characteristics of trajectories of outflows resulting from the application of this control method are analyzed. Afterwards, the results of the series of simulation experiments based on a large set of historical data concerning a big Polish reservoir are presented.     

基于变频器的水位自动控制系统设计

针对传统人工控制水泵自动化水平低、电能浪费严重的问题,设计出一种采用变频器和水位压力传感器相结合的系统,利用变频器内置PID功能,控制水泵流量,从而实现蓄水池水位的自动控制。给出了设备选型、线路原理图、变频器内置PID参数计算和相关参数设置。     

Medium term scheduling of a hydro-thermal system using stochastic model predictive control

A multistage stochastic programming formulation is presented for monthly production planning of a hydro-thermal system. Stochasticity from variations in water reservoir inflows and fluctuations in demand of electric energy are considered explicitly. The problem can be solved efficiently via Nested Benders Decomposition. The solution is implemented in a model predictive control setup and performance of this control technique is demonstrated in simulations. Tuning parameters, such as prediction horizon and shape of the stochastic programming tree are identified and their effects are analyzed.     

Dynamic fuzzy criterion model for reservoir operations and a case study

Reservoir operation is a special inventory problem under conditions of uncertain supply and controlled demand. In this paper, we will restrict our attention to reservoir operations. In many cases, the problem which the reservoir manager is concerned with is not to maximize the direct economic benefit, but to operate the reservoir system as normally as possible, i.e., to fulfill the requirement for water demand, recreation, fishing, generating electricity, and ecology, etc., and to avoid flooding, as much as possible. This paper presents a dynamic fuzzy criterion model (DFCM) for reservoir operations. In DFCM, a satisfactory degree function is adopted as a criterion function. The objective is to let the reservoir system be in the highest possible satisfactory state. This model is available to the reservoir system whose parameters are fuzzy or whose economical benefits are very difficult to measure. We obtain the existence, uniqueness, and stability theorems to the equation of DFCM, and prove that the optimal release policy for a reservoir is a bounded critical number policy. Finally, the application of DFCM in Qinhuangdao region water resource system is discussed.     

基于遗传算法的灌区通用水资源整体优化配置模型

解决水资源的优化问题大多采用开源节流、加强管理等措施,而这只能是解决问题的外因。水资源的合理配置问题,最好由用水者的利益激励机制来解决,这样才能从根本上解决水资源的短缺和低效率应用问题。基于遗传算法,结合利益激励机制,对冯家山水资源优化配置方案进行探讨。为水资源分配和管理提供参考。     

A linear programming regulator applied to hydroelectric reservoir level control

For linear dynamical systems with linear state and control constraints the regulator problem can be formulated as a linear programming problem. A regulator, built around a standard LP program and operating in the Open Loop Optimal Feedback (OLOF) fashion, is presented.The LP-OLOF regulator was implemented on a VAX 11/780 computer to control, in real time, a double water tank laboratory process, and the water level of a hydroelectric power station reservoir.The reservoir control experiment showed that even with an assumed simple process model, satisfactory performance was achieved. In particular it was beneficial that the LP-OLOF regulator allows dynamic changes of the water flow bounds corresponding to the number of generators available at different operating conditions, and that the regulator can predict the water level.     

油田注水井工况实时分析及管理系统开发与应用

注水是油田保持地层能量,维持高效经济开发最有效的手段.随着国内油田相继进入高含水开发期,稳产难度日益增大,油田数字化管理模式下如何加强精细注水管理,确保油藏“注好水,注够水”,是各大油田持续稳产面临的关键问题.研发的油田注水井工况分析及管理系统,利用多信息融合、数据集成及计算机技术,通过特定的融合模型及算法,实现注水井工况分析诊断、故障预警、指标统计、远程调配、注水曲线及报表自动生成等功能.系统采用B/S＋C/S架构,模块化设计,自动化数据与信息化融为一体.该系统在长庆油田l万余口注水井上应用,为油藏精细注水开发管理提供了有力的工具.     

An Active Decision Support System for Optimality in Open Air Reservoir Release Strategies

Decisions regarding good release strategies for large open air reservoirs may be surprisingly complex, even for experienced reservoir managers. This is due to the dual requirement that water levels should neither be kept too high (resulting in excessive evaporation) nor too low (resulting in an inability to supply water during particularly dry periods). Decisions do not only affect the reservoir's efficiency in the short term, but may also do so in the long run, and this significantly complicates matters. A new decision support system called ORMADSS (for Optimal Reservoir Management Active Decision Support System) is discussed here. This system is designed to aid medium-scale reservoir managers in their complicated decision-making processes. The visually attractive and informative computer-implemented system is based on determining an optimal release strategy for years of average climate and then attempting to steer release strategies for non-average years in such a manner that the reservoir content approaches the optimal level for average years, while still satisfying legal and environmental constraints, as well as demand set by reservoir users. The success of ORMADSS is discussed in a special case study regarding its implementation at Keerom Dam, the second-largest privately-owned open air reservoir in South Africa.     

Neuro-dynamic programming for designing water reservoir network management policies

Stochastic dynamic programming (SDP) can improve the management of a multipurpose water reservoir by generating management policies which are efficient with respect to the management objectives (flood protection, water supply for irrigation, hydropower generation, etc.). The improvement in efficiency is even more remarkable for networks of reservoirs. Unfortunately, SDP is affected by the well-known ‘curse of dimensionality’, i.e. computational time and computer memory occupation increase exponentially with the dimension of the problem (number of reservoirs), and the problem rapidly becomes intractable. Neuro-dynamic programming (NDP) can sensibly mitigate this limitation by approximating Bellman functions with artificial neural networks (ANNs). In this paper the application of NDP to the problem of the management of reservoir networks is introduced. Results obtained in a real-world case study are finally presented.     

油藏注水开发低阶模型及最优控制仿真研究

油藏注水开发最优控制问题计算规模大、控制变量与计算网格多,且控制变量与目标函数之间的关系为一组非线性偏微分方程控制,若直接进行数值求解,对于目前的计算机计算速度和存储空间是个巨大负担.本文采用最佳正交分解(proper orthogonal decomposition,POD)方法提出了基于低阶模型的油藏注水开发最优控制问题,这样,控制变量与目标函数之间的复杂关系被转变为解析函数,仅以少量的POD系数作为优化变量且只需采用非线性规划方法即可求解,大幅度地降低了原问题的求解复杂度与计算量.以二维五点井网的一个井组为应用实例进行仿真研究,结果表明:基于低阶模型的最优控制问题所求解的最大生产净现值与经典的伴随梯度法相比仅有不超过2.5%的误差,且计算速度优势极为明显,当网格数为40×40时,计算速度可提高30倍以上,网格数越多,计算速度优势越明显,当网格数为70×70时,可提速60倍以上.     

基于网络信息与遥感影像的水库自动提取方法研究

针对传统建立水库相关数据库的方法多为线下人工统计，受到诸多因素制约的缺陷，将网络信息、电子地图及遥感影像等数据综合利用起来，实现水库自动提取。利用网络爬虫从官方水利政务网站抓取相关信息，筛选出最新的水库名称及所属地等数据，再根据水库名称及所属地，调用百度、高德等地图网站提供的应用接口，获取水库的空间坐标信息，并利用水库坐标对遥感影像做缓冲区分析，提取出水库水体范围，得到 1 个含有水库名称、坐标、面矢量图的水库基础数据库。经过验证，提取结果的查准率为 0.973 5，查全率为 0.611 3， 作为二者的调和平均值达到 0.751，能够完整监测并提取出大中型水库，但对小型水库的监测提取效果一般，可解决传统水库提取方法需要先验知识的问题，提高对水库的区域性动态监测能力。     

北大港水库数字孪生建设方案与要点探讨

为提升北大港水库工程管理现代化与智慧化水平，结合北大港水库“数字河库”建设现状和水库扩容工程规划，提出北大港水库数字孪生建设方案，搭建数字孪生工程建设总体框架与主要内容，丰富 L2 和 L3 级数据底板， 构建模型库和知识库，实现建设期和运维期的智能应用建设。对安全监测数据底板、工程安全模型等数字孪生建设难点，以及实现“四大安全”与全过程、全要素管理等进行探讨。实现北大港水库流域防洪调度、水资源管理与调配，以及其他各项业务管理的数字化、网络化、智能化水平提升，有效推进水库运营管理数字化转型和智能化升级。     

Total control-based unified allocation model for allowable basin water withdrawal and sewage discharge

In this paper,a new model with a total amount control target of allowable water withdrawal based on initial water right is built for the implementation of initial water right allocation scheme as well as unified allocation for allowable water withdrawal and sewage discharge.The model couples the water allocation simulation model and the computational model of permissible pol-lution bearing capacity.In view of the model complexity,a new technology which synthesizes system simulation,iterative reservoir turns...     

Computation of natural frequencies and mode shapes of arch dams as an inverse problem

In this paper, a procedure is developed which can be used to identify the natural frequencies and natural modes of an Arch-Dam in a vacuum, from forced vibration testing data of partially filled reservoir, throughout removing the effect of hydrodynamic, by using an effective algorithm. The resonance frequency and the resonance mode of the dam–reservoir system have been computed from the in situ tested data. The solution strategy is verified by studying the dynamic response of simple structures, like beam with the fluid interaction effect taken into account, as the analytical results of its modal properties were available for comparison. The hydrodynamic pressure of the reservoir is calculated using the boundary element method. In the inverse problem procedure, the calculated resonance replaces the measured resonance, which has been obtained practically throughout the in situ testing. In this paper the strategies are extended to analyse the dynamic beam–fluid interaction problem with compressible water. The results derived by solving an inverse problem are compared with the exact analytical responses of the beam.     

Optimal feedback control of oil reservoir waterflooding processes

Waterflooding is a process where water is injected into an oil reservoir to supplement its natural pressure for increment in productivity. The reservoir properties are highly heterogeneous, its states change as production progresses which require varying injection and production settings for economic recovery. As water is injected into the reservoir, more oil is expected to be produced. There is also likelihood that water is produced in association with the oil. The worst case is when the injected water meanders through the reservoir, it bypasses pools of oil and gets produced. Therefore, any effort geared toward finding the optimal settings to maximize the value of this venture can never be over emphasized. Waterflooding can be formulated as an optimal control problem. However, traditional optimal control is an open-loop solution, hence cannot cope with various uncertainties inevitably existing in any practical systems. Reservoir models are highly uncertain. Its properties are known with some degrees of certainty near the well-bore region only. In this work, a novel data-driven approach for control variable (CV) selection was proposed and applied to reservoir waterflooding process for a feedback strategy resulting in optimal or near optimal operation. The results indicated that the feedback control method was close to optimal in the absence of uncertainty. The loss recorded in the value of performance index, net present value (NPV) was only 0.26%. Furthermore, the new strategy performs better than the open-loop optimal control solution when system/model mismatch was considered. The performance depends on the scale of the uncertainty introduced. A gain in NPV as high as 30.04% was obtained.     

Performance analysis of artificial bee colony (ABC) algorithm in optimizing release policy of Aswan High Dam

The paper presents a study on developing an effective reservoir operation policy by using artificial bee colony (ABC) algorithm. The decision maker of a reservoir system always needs a guideline to operate the reservoir in an optimal way. Such guidelines named ‘release curves’ have developed for high-, medium-, and low-inflow category that can answer how much water needs to be released for a month by observing the reservoir level (storage condition). The Aswan High Dam of Egypt has been considered for the case study. For comparing the model efficiency, another heuristic approach—genetic algorithm (GA)—has been used. So far, GA is well established and most popular in reservoir release optimization. Historical inflow data for 18 years have been used for simulation purpose, and the general system performance-measuring indices (such as reliability, resiliency, and vulnerability) have been measured. The application procedure and problem formulation of ABC are very simple and can be used in optimizing reservoir system. After using the actual historical inflow, the release policy succeeded in meeting demand for about 98 % of the total time period. According to the simulation results, ABC algorithm showed better performance than the GA approach in reservoir release optimization.     

多目标水库资源优化调度决策支持系统及应用

水资源调度是水库运行管理的中心环节和复杂的过程。水库优化调度是涉及入径流、工农业供水、发电等多目标决策问题。运用三库DSS结构设计由数据库、模型库、管理策略方法库和业务操作4部分模块组成的水库资源优化调度决策支持系统,建立基于成本函数和基于决策者偏好的效用函数的目标规划模型,实现水库资源的优化调度策略。     

Modeling and optimization of activated sludge bioreactors for wastewater treatment taking into account spatial inhomogeneities

In this work, we study optimal and suboptimal control strategies for the treatment of a polluted water resource by using aside a continuous bioreactor. The control consists in choosing the inlet volumetric flow rate for filling the bioreactor with contaminated water from a considered resource (lake, reservoir, water-table, …). The treated outflow returns to the resource. We tackle an optimization problem which aims to minimize the time needed to reach a prescribed minimal value of contamination in the resource by choosing the input flow. Next, we study the influence of inhomogeneities of concentrations in the bioreactor, considering a system based on partial differential equations which describe its dynamics. We show that applying the optimal feedback control derived for perfectly mixed bioreactor does not allow to reach the target with small diffusion parameters as it drives the bioreactor to washout (the bioreactor equilibrium with no biomass). In this case, a suboptimal feedback (which reaches the target in finite time) is obtained with the help of a Hybrid Genetic Algorithm. Furthermore, we consider that the fluid flow velocity of the water entering into the bioreactor follows either a uniform or a nonuniform profile, showing that the optimal volumetric flow rates obtained with the uniform profile are not optimal if the profile is nonuniform, even when high diffusion coefficients are considered in the model.     

Driving mechanisms of CM-scaled PDMS boats of respective close and open reservoirs

A floating solid object may have a spontaneous motion on a water surface when a liquid, which has a surface tension lower than water, exits the solid object and has contact with water. This motion may be induced due to the difference between surface tensions of water and the liquid. In order to interpret this motion, it is important to know how the liquid exits the solid object. In this article, we reported in situ observation of exchange processes of water and isopropyl alcohol (IPA) inside both close and open reservoirs of cm-scaled polydimethylsiloxane (PDMS) boats. Based on this observation and force analysis, we interpreted driving mechanisms of these boats. We found that the exchange processes may be different in the PDMS boats of respective close and open reservoirs. The PDMS boat of a close reservoir might have a bubble trapped in its reservoir during the motion. This bubble slowed down the exiting process of the IPA from the reservoir, made the motion last longer, and enabled the boat to have a longer travel distance. Also, such a boat had gurgling-like motions (i.e., approximately periodic motions of deceleration and acceleration) after the majority of the IPA had exited the reservoir. The speeds of this boat had an order of 1?cm/s. On the other hand, neither bubbles nor gurgling-like phenomena were found in the motions of the PDMS boat of an open reservoir. The speeds of this boat were in the order of 1?cm/s as well. In addition, based on observed exiting processes of the IPA and experimentally determined speed-time relationships, we also set up a simple model to find force?Ctime relationships. Furthermore, we investigated the exiting process when the open reservoir of the cm-scaled PDMS boat was shallow. We found that, depending on the values of the height difference, h, between the bottom of the reservoir and the water surface outside the reservoir, three different phenomena might appear: (1) if h????1.33?mm, then the reservoir was empty at the end of the test and no water flowed into the reservoir during the test; (2) if 1.3?mm?<?h????2.3?mm, then the reservoir was empty at the end of the test while water flowed into the reservoir during the test; and (3) if 2.3?mm?<?h????3.0?mm, then the reservoir was filled by water at the end of the test. The difference in the filling results was induced by the interplay among Marangoni effect, free convection, and recovery of a hollow spot by surrounding water. The corresponding findings interpreted the exiting process of the IPA observed in the open reservoir of a mm-scaled SU-8 boat that we have previously developed, and also explained the filling result in the open reservoir of a PDMS boat.