基于最优潮流理论的风电、梯级水电短期联合优化调度

为了协调多电源短期联合调度方案经济性与可靠性之间的关系,需要建立高效、实用的模型,并采用新型优化算法对调度模型进行求解。本文基于最优潮流理论建立多电源短期联合优化调度模型,在目标函数中考虑电力系统的经济性与可靠性指标,在约束条件中考虑电源约束条件和电网约束条件。在计算发电系统可靠性时,采用基于运行状态的瞬时可靠性评估法,有效避免了传统可靠性评估方法在评估风电等波动性较大电源方面的不足。最后以IEEE-30节点系统为例验证本文提出的优化调度模型和算法,结果表明,本文的联合调度策略可提高系统的可靠性指标,降低风电场的弃风量,增加梯级水电与风电的上网电量,保证火电输出功率的平稳性。     

互联电网共享运行备用可靠性评估

提出了互联电网共享运行备用可靠性评估算法和指标。基于能量管理系统提供的电网实时运行信息,计及区域联络线约束、在线机组状态、网损、负荷波动等随机因素对运行备用可靠性的影响,将分区评估与全网评估相结合,评估了各子区域对全网可靠性的影响。华东电网的评估算例表明,该算法可以定量评估实时系统各子区域对维持全网可靠运行所作出的贡献,为共享备用分摊计算提供依据。     

推力轴承在线监测系统在仙游抽水蓄能电站的应用

通过在仙游抽水蓄能电站加装GMH550推力轴承在线监测系统,实现了对推力轴承运行状态、健康状况实时在线监测,并对推力轴承运行中存在的潜在缺陷和问题进行评估和预判,确保推力轴承运行的稳定性和安全性。主要功能涵盖了对推力轴承运行状态的全面监测、对推力瓦与镜板间油膜厚度的实时监测及报警、推力轴承运行状态自动评价及故障诊断和推力轴承检修状态自动评价。介绍GMH550推力轴承在线监测系统与功能和在仙游抽水蓄能电站的实际应用与效果,为推广推力轴承在线监测系统在行业的发展做出一份贡献。     

水工金属结构远程监控及安全管理系统研究

针对水工金属结构存在的缺乏实时在线监测、监测数据存储及传输方式落后、缺少远程共享管理平台及实时安全评估机制等问题,构建了一套可支持数据动态采集、数据高效存储及实时传输、实现远程监控及实时安全评估的水工金属结构远程监控及安全管理系统,建立了系统的体系结构和运行流程。在此基础上,对基于信息采集终端的运行状态数据采集与收发技术、基于互联网技术的数据传递方法及管理平台和分类分层方法以及安全度概念的安全评估机制等关键技术进行了研究。该系统已成功应用于云南某水电站,取得了良好的效果。     

电力自动化系统UPS供电方案可靠性

不间断电源(UPS）紧急供电系统是电力自动化系统安全可靠运行的根本保证，因此有必要对其可靠性进行定量评估分析。文中将UPS系统分为13个功能模块,并根据各模块特点，建立了相应的精确多状态Monte-Carlo可靠性数学模型，创建了基于模块的UPS系统故障树。在此基础上提出了基于时序Monte-Carlo仿真的UPS系统可靠性指标求解及灵敏度分析方法。以一实际UPS系统为例，应用所提出的方法对其可靠性进行评估，获得了最优的可靠性增强措施。该方法不仅适用于电力自动化系统UPS供电方案，也适用于其他各种紧急供电系统的可靠性定量分析。     

电力系统在线安全稳定评估及决策技术的研究

阐述了电力系统在线安全稳定评估及决策的概念及其对电网预防控制、暂稳控制、电压稳定控制等方面的重要作用，认为电力系统在线安全稳定评估及决策是今后电网稳定运行和控制的发展方向。对实现在线评估及决策的条件进行了分析和评述，指出电力系统运行状态数据采集的快速性、同时性、可靠性是实现在线评估及决策系统的重要基础，提出了构建电网统一数据平台的设想和建议，并介绍了福建电网在线决策系统的工程实践。     

智能化控制在引水隧洞斜井提升机电控系统的应用

文章对滇中引水工程香炉山隧道2号施工斜井提升机普通电控、PLC及变频电控三种方案进行了详细分析研究,建立了基于双PLC控制的变频提升机电控系统,并进行了应用与关键技术实践验证。结果表明：将PLC控制功能与全数字变频技术相结合,极大提高了提升机运行的稳定性和可靠性,调速精度高,能够实现电机满功率向电网进行能量回馈。基于S7-300的双PLC主控制系统是整个控制系统的核心,能对提升机电控系统的实时运行状态进行采集,从而对电机进行精确、稳定的控制;通过位移传感器、摄像头等多传感器在线监测,实现了提升机系统闸瓦磨损监控、信号通信、视频监控与远程故障诊断。     

火电厂的实时状态监测系统与故障诊断

针对国内大多数火电厂现场设备控制的现状，提出一个经济型实时状态监测系统方案，在充分利用原有设备的前提下，采用集散控制系统(DCS)结构和FIX组态软件实现某厂各主要站点的集中监视和统一管理。在此基础上，利用实时状态数据对主要设备运行状态进行评估，对设备故障进行预测和诊断。现场运行结果表明：该系统对火电厂的现场设备实现了有效的集中监视，并可对主要设备进行故障预测和初步诊断。     

基于在线辨识的实时最优励磁控制器

设计了一种在线实时最优励磁控制器(RTOEC)，其辨识器能够由发电机运行状态的变化采用非线性最小二乘法辨识法准确辨识出单机无穷大模型中的系统参数，从而可根据辨识结果及其系统所遭受的扰动，通过线性最优控制理论实时计算出线性最优励磁控制的反馈增益矩阵，以适应系统当前的运行点和所遭受的干扰。仿真结果表明，所设计的RTOEC能够适应系统运行状态的大范围变化，在大小扰动下均表现出良好的控制性能，有效提高了电力系统的静态和暂态稳定性。     

基于数字化模型的水轮机调速系统状态监测与分析

从状态检修角度出发，提出了基于数字化模型的调速系统状态监测与状态分析方法。该方法通过调速系统设备分析确定了测点布置和数据采集方案，在状态监测的基础上，以机组运行工况为线索，结合调速系统数字化模型对水轮机调速系统设备进行状态评估，采用事件触发和约束传播机制进行设备故障诊断，并以可视化模型指示调速系统设备健康状态和变化趋势，为实现调速系统状态检修打下基础。     

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。     

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。     

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.     

Changes in Summer Irrigated Crop Area and Water Use in Southeastern Turkey from 1993 to 2002: Implications for Current and Future Water Resources

Changes in summer irrigated cropland acreage and related water use are estimated from satellite remote sensing and ancillary data in semi-arid Southeastern Turkey where traditionally dry agricultural lands are being rapidly transformed into irrigated fields with the help of water from the Euphrates-Tigris Rivers. An image classification methodology based on thresholding of Landsat NDVI images from the peak summer period reveals that the total area of summer irrigated crops has increased three-fold (from 35,000 ha to over 100,000) in the Harran Plain between 1993 and 2002. Coupled analysis of annual irrigated crop area from remote sensing and potential evapotranspiration based estimates of irrigation water requirements for cotton indicate a corresponding increase in agricultural water use from about 370 million cubic meters to over one billion cubic meters, a volume in accordance with the state estimates. These estimates have important implications for understanding the rapid changes in current agricultural withdrawals in Southeastern Turkey and form a quantitative basis for exploring the changes in future water demands in the region. For example, expansion of irrigated lands have led to a steady decrease in potential evaporation due to increased roughness and decreased humidity deficit in the Harran Plain. Assuming that the changes in future evaporation conditions will be of similar nature, water use for irrigation is expected to decrease over 40 percent in future irrigation sites. Incorporating this decrease in overall planning of the irrigation projects currently under construction should lead to improved management, and by extension, sustainability of water resources in the region.     

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。