基于在线学习的水轮发电机组智能控制系统研究

针对水轮机调节系统非线性、结构参数变化范围较大的特点，提出了一种能够在线学习的智 能控制系统。它以模糊神经网络为学习器，以模糊推理和智能处理机构为控制器，将两者结 合起来共同完成水轮发电机组的调节任务，并详细讨论了学习器的建立和学习方法及智能控 制系统的运行方式。仿真研究表明，其有较强的学习能力、良好的实时控制性能，能适应水 轮机调节系统结构、参数变化较大情况下的控制要求。     

水轮机调节系统自适应滑模控制策略

水轮机系统惯性参数是影响水轮机调节系统动态特性的重要参数，传统控制方法大都是基于水轮机及其引水系统近似简化模型，很难改善水轮机调节系统动态特性。应用径向基函数神经网络逼近水轮机及其引水系统非线性特性，利用李雅普诺夫稳定性理论设计并证明水轮机系统惯性参数自适应估计律，设计了一种基于水轮机系统非线性特性和惯性参数估计的滑模鲁棒控制器，并完成仿真实验。仿真结果表明，该滑模鲁棒控制水轮机调节系统具有较高的跟踪精度、控制器输出抖振较小等优点，为水轮机调节系统高精度转速跟踪提供有效参考。     

基于遗传算法的水轮机模糊自适应PID调节系统控制规则

针对水轮机调节系统常规PID控制参数不能根据系统的动态过程自动调整控制参数的问题，结合遗传算法与模糊PID控制，用遗传算法优化模糊自适应PID控制的模糊规则，利用模糊推理的方法求解PID参数的变化量，对PID参数进行自动整定。同时针对遗传算法寻优生成的模糊规则存在跳变和规则曲面粗糙等缺陷，在目标函数中引入光滑因子，有效解决了模糊规则跳变现象。仿真表明，该方法是寻找水轮机调节系统模糊自适应PID控制规则的一种可行方法。     

水轮机调节系统控制策略综述

综述水轮机调节系统常规PID控制、自适应控制、智能控制和非线性控制的特点,指出模糊控制和专家控制精度较低;神经元网络控制学习速度较慢、易收敛到局部最小点;遗传算法可有效地解决参数寻优问题;非线性控制着眼于水轮机调节系统的非线性特性,控制效果较好.提出将非线性控制与其它控制策略相结合形成复合控制,将是水轮机调节系统控制策略的发展方向.     

调节对象参数和运动特性随工况变化的分析

水轮机调节对象的许多参数都是随运行工况变化的。以调节对象线性化模型为基础，从1个实例计算人手，计算了不同工况下水轮机传递系数和发电机6个参数的变化情况，进而计算这些参数变化对捌节对象特征根的影响。通过汁算表明，其水力振荡衰减速度与出力有关．而系统的其他运动特性随工况变化较小。     

在水轮机调节系统动力学分析中描述水轮机特性的一种新方法

一、问题的提出利用电子计算机分析水轮机调节系统动力学特性,通常用数据表格插值法确定水轮机特性参数。引水系统中的水击现象是水轮机调节系统的重要特性,它的本质是一个反向微分环节,构成力矩反抛现象。这表明在调节过程的起始阶段力矩变化与调节目的相反。     

智能控制技术在水轮机调节系统中的应用

概述了水轮机调节系统的特点以及智能控制技术的发展历史与现状，着重介绍了智能控制中模糊控制、神经网络控制、专家控制、遗传算法等的特点及在水轮机调节系统中的应用情况，并提出智能控制技术作为水轮机调节系统的一种新型控制技术必然朝着综合化、集成化方向发展。     

基于Matlab/Simulink的水轮机调节仿真研究

针对物理模型建造、参数改变困难的情况,在Matlab/Simulink工具箱下建立了水轮机调节系统仿真模型。考虑到水轮机特性的非线性和引水管道长的特点,水轮机模型采用了非线性模型、引水系统采用了弹性水击模型,仿真计算结果与实测结果吻合得很好。通过仿真模拟各种工况下水轮机的运行,有助于了解水轮机调节系统实际运行中的变化情况。对Simulink下的水轮机调节系统的数学模型、仿真实验结果与实测值的对比分析作了简要介绍。     

BP网络模糊PID控制在水轮机调速器中的应用

为了改善水轮发电机组的动态调节品质,对神经网络控制在水轮机调节中的应用进行理论分析,将基于BP神经网络的模糊PID控制器应用于水轮机调速系统.仿真和实验结果表明,该控制器具有良好的调节品质,其控制作用对改善水电机组的动静态特性和对参数时变的适应能力等方面均优于常规PID调节器,为神经网络控制在水轮机调节系统中的应用打下了良好的理论基础.     

水轮机调节系统的MATLAB仿真模型

介绍了水轮机调节系统建模及其分析方法.仿真模型是基于MATLAB Simulink建立的,能实现水轮机调节系统空载运行、甩100%额定负荷、接力器不动时间、孤立电网运行和一次调频等动态过程的仿真.仿真结果有助于加深对水轮机调节系统基本原理的理解,也有助于了解被控制系统参数(调节对象)和水轮机控制系统(调速器)参数对水轮机调节系统动态特性的影响.     

Call for Papers

正As the eldest and most distributed professional journal of water industry,Water Wastewater Engineering(W WE)gained very wide acceptance from the colleagues working in this field in this country since start publication in 1964.Now it is administrated by the Ministry of Construction of the People’s Republic of China and sponsored by the China Civil Engineering Society etc.     

地下厂房施工过程的三维非线性数值模拟分析

根据冗各电站地下厂房开挖支护的施工顺序,以隐式杆单元模拟锚杆,以壳单元模拟混凝土喷层,采用三维非线性有限元技术,对洞室群的开挖支护动态过程进行了模拟计算。通过三维非线性有限元计算分析得到:洞室群动态开挖过程中围岩应力变形的分布规律,围岩塑性区的发展规律,锚杆受力变化情况。计算结果表明:整个开挖过程中,洞周围岩位移变化规律正常,量值较小,塑性区主要分布在洞室周边,围岩稳定性较好;但在洞室交叉口处围岩的变形较大,出现较大范围的塑性区,在此基础上提出了支护措施优化方案,并对优化方案的效果进行了评价。     

Serial discontinuities in a Rocky mountain river. I. Distribution and abundance of plecoptera

Samples were taken year-round at eleven sites along the altitudinal profile (2900-1400 m a.s.l.) of the Gunnison River, a 329 km tributary of the Colorado River, to document the distribution of the Plecoptera and to evaluate responses to hypolimnial-release dams in the headwaters and middle reaches. Twenty-two species were present, with the greatest species richness occurring in an unregulated segment upstream of the middle reach dams; average nymphal biomass over the study period (175 organisms, 395 mg dry mass m^?2) was also greatest in this segment. Only four species (58 organisms, 48 mg m^?2) were present in the tailwaters of the headwater dam and values were greatly reduced (nine species; 35 organisms, 180 mg m^?2) below the middle reach dams. The stonefly community recovered ca. 80 km downstream from the last dam (15 species; 244 organisms, 250 mg m^?2), apparently in response to natural resetting of environmental conditions corresponding to those above the middle reach dams. At the most downstream site (11) only four species (four organisms, 16 mg m^?2) were present. The observed distributional pattern is a classic serial discontinuity in response to hypolimnial stream regulation in a temperate latitude river.     

Impacts of Microcystis on algal biodiversity and use of new technology to remove Microcystis and dissolved nutrients

Cyanobacteria often dominate eutrophic lakes, outcompeting green algae that are required by fish and zooplankton. This study was undertaken to ascertain the impact of the cyanobacterium, Microcystis, on algal biodiversity. Under laboratory conditions, we found that the presence of Microcystis decreased phyla richness by 58%, phyla evenness by 47%, genera richness by 66% and genera evenness by 51%. Analysis by mixed anova s demonstrated a significant interaction between treatment and time and confirmed a significant reduction in richness and evenness of phyla and genera. We also conducted a phosphate restriction assay on the algae in Mason Lake (Irvine, CA, USA) and found that the threshold needed for algal growth there was 0.02 mg L^?1 PO₄. A pilot study was then conducted to test the effectiveness of the Blue Pro? water treatment facility in removal of this colonial organism from Mason Lake, in addition to removal of dissolved nutrients required for its growth. We measured a 97% reduction in Microcystis cells, a 72% reduction in chlorophyll‐a, and a 96% reduction in phosphate after just one 10 min cycle through the unit. Our study demonstrated that removal of Microcystis colonies may allow green algae to increase in numbers. This may improve algal biodiversity, which will benefit zooplankton and fishes.     

Evaluation of freshwater mussel relocation as a conservation and management strategy

The relocation of unionacean mussels is commonly used as a conservation and management tool in large rivers and streams. Relocation has been used to recolonize areas where mussel populations have been eliminated by prior pollution events, to remove mussels from construction zones and to re-establish populations of endangered species. More recently, relocation has been used to protect native freshwater mussels from colonization by the exotic zebra mussel Dreissena polymorpha. We conducted a literature review of mussel relocations and evaluated their relative success as a conservation and management strategy. We found that 43% of all relocations were conducted because of construction projects that were forced to comply with the Endangered Species Act 1973 and that only 16% were monitored for five or more consecutive years. Most (43%) relocation projects were conducted from July to September, presumably a period when reproductive stress is relatively low for most species and the metabolic rate is sufficient for reburrowing in the substrate. The mortality of relocated mussels was unreported in 27% of projects; reported mortality varied widely among projects and species and was difficult to assess. The mean mortality of relocated mussels was 49% based on an average recovery rate of 43%. There is little guidance on the methods for relocation or for monitoring the subsequent long-term status of relocated mussels. Based on this evaluation, research is needed to develop criteria for selecting a suitable relocation site and to establish appropriate methods and guidelines for conducting relocation projects.     

基于模型试验的河床砂砾石层基本特性研究

为了经济可靠地确定深厚覆盖层的基本特性参数,以大渡河双江口水电站坝基河床砂砾石层基本特性研究为工程背景,进行大尺寸模型试验,研究河床砂砾石层的旁压模量和动探击数随密度、级配以及上覆压力的变化规律。根据室内模型试验结果,结合现场旁压试验及钻孔试验成果,推断出坝址区河床砂砾石相关层位的密度,并依此进行砂砾石室内力学试验,获得设计所需力学参数。研究成果可为深厚覆盖层基本特性测试提供新的方法。     

SPATIAL AND TEMPORAL WATER QUALITY VARIABILITY IN AQUATIC HABITATS OF A CULTIVATED FLOODPLAIN

The floodplains of lowland rivers contain diverse aquatic habitats that provide valuable ecosystem services but are perturbed when intensively cultivated. Hydrologic, water chemistry and biological (fish) conditions in five aquatic habitats along the Coldwater River, Mississippi, were measured for more than 4 years: the river, two severed meanders that functioned as backwaters, a managed wetland and an ephemeral channel draining cultivated fields. Off‐channel habitats were connected to downstream regions 0.10% to 32% of the dry season and 24% to 67% of the wet season. The median temperatures for the five monitored sites ranged from 18°C to 23°C, the median total solids concentration for all sites was 135 mg L^?1, the median total phosphorus was 0.29 mg L^?1 and the median total nitrogen was 1.56 mg L^?1. Chemical and physical water quality displayed strong seasonal differences between the wet winter/spring and the dry summer/fall periods so that temporal variation consisted of gradual seasonal trends superimposed on strong diurnal variations. All off‐channel habitats exhibited periods of hypoxia and temperatures >30°C during the dry season. Between‐site gradients of water and habitat quality were strongly coupled to water depth and runoff loading. The rehabilitation of one backwater by increasing water depth and diverting agricultural runoff was associated with improved water quality and fish species richness relative to an adjacent untreated backwater. The diversion of polluted runoff and the use of water control structures to maintain greater water depth were observed to be effective management tools, but the former reduces the water supply to habitats that tend to dry up and the latter reduces connectivity. Published in 2011 by John Wiley & Sons, Ltd.     

库水波动下库岸边坡地下水浸润线解析解及误差分析

解析法是库岸边坡地下水浸润线计算中便于实际应用的方法,但该方法须基于若干假定并对潜水运动基本方程线性化后才能求解。针对各假定和线性化过程建立不同的地下水渗流数学模型,用解析法和有限元法解答上述数学模型,分析各误差大小及其规律。结果表明：库岸垂直处理带来的误差要小于方程线性化处理和不考虑非饱和渗流带来的误差,而且它们都随渗透系数变大而减小;在三峡库区库水调度情况下,假定库水位等速变化带来的误差对大多岸坡而言可以忽略;计算库岸边坡地下水浸润线时,解析法只适用于水位变化幅度相比含水层厚度较小,且几何边界规则、岩土结构简单、岩土体渗透性较好时的情况。     

簸箕李引黄灌区水沙分布及优化调度的经验

灌区利用水沙观测所取得的资料和试验数据，运用水沙运动力学理论，总结分析和揭示了灌区水沙分布的规律和特点。在此基础上，结合灌区的实际运行情况，围绕减少骨干渠道的淤积进行探讨、研究，进而，优化水沙调度方案。该方案实施后，骨干渠道减旅伴效果明显，取得了成功的经验。     

小湾水库大坝防渗面板及其裂缝的加固处理

小湾水库大坝防渗面板整体抗渗性能差,且存在多条裂缝,通过对面板钢丝网喷涂丙乳砂浆加固处理及其裂缝修补,大坝渗漏量明显减少,且左岸上灌浆廊道内及大坝下游坝面92～93 m高程下廊道入口处原有小股射流全部消失.