分散式变电站监控系统中的通信技术方案

通过分析变电站内信息流向及流量，提出了适应站内通信系统的几种方案，并对其进行了 分析比较，特别 研究了总线型的通信系统实现方案，认为在目前阶段基于CAN总 线技术的通信系统具有优势。指出现场总线 技术必将应用于变电站自动化系统中，并需要 对传统的变电站按一次、二次划分的设计 观念进行更新，以 实现基于现场总线控制系统的一体化智能变电站。     

基于CAN总线的新型馈线自动化系统

介绍了基于CAN总线的馈线自动化系统构成，为了提高馈线自动化系统的实时性和可靠性，提出了以屏蔽双绞线为通信介质的CAN总线局域网作为馈线自动化系统的通信基础，并根据CAN总线的特性，采用了对称型多主站网络结构；对现阶段配电网自动化系统的馈线故障隔离技术提出了改进建议；该系统经在模拟系统上的测试和现场运行情况验证，具有可靠性高、实时性好、系统成本低的优点。     

基于工业实时以太网POWERLINK的网络时钟同步方法的研究

本文介绍了工业实时以太网Ethernet POWERLINK通信中网络时钟同步的方法,并进行了测试,给出了基于FPGA硬件平台的POWERLINK网络时钟同步精度的测试结果.     

Powerlink 实时以太网的实现与测试

由于工业自动化领域技术不断发展,自身需求不断提高,早期的一些现场总线的局限性日益突显。实时以太网以其自身的优势在工业自动化控制中逐渐成为一种趋势。目前,一些实时以太网已能提供强确定性、实时性的支持。通过比较,选择对 Powerlink 实时以太网进行研究,实现了 Powerlink 的总线控制器,并模拟工业控制的主干网络,对 Powerlink 实时以太网的性能进行测试,最终证明了 Pow-erlink 实时以太网的高可靠性与高实时性。     

风电机组变桨超级电容备用电源状态检测系统设计

课题基于STC15F2K60S2单片机控制设计使用CAN总线进行数据传输,实现对风电机组变桨超级电容备用电源状态检测。硬件部分包括单片机主控模块、电压检测模块、电流检测模块、温度检测模块以及CAN总线数据传输系统;软件部分包括单片机主程序、电压检测程序、电流检测程序、温度检测程序以及CAN总线数据传输程序。设计采用STC15系列单片机作为主控芯片,比市场上常见的51系列单片机更加先进,拥有更好的可扩展性。同时,设计使用CAN总线技术作为数据传输系统,增强了系统的数据传输能力,确保了系统传输数据的实时性。     

CAN总线在配电自动化系统中的应用研究

介绍了CAN总线的特点及其通信协议，应用CAN总线设计了配电自动化系统的总体结构，最后举出了我国典型的10kv配电环网实例。实践证明，CAN总线可靠性高，造价低，在配电自动化通信系统中拥有广泛的应用前景。     

嵌入式通信管理装置的设计和实现

介绍了一种采用嵌入式Linux操作系统和PC／104嵌入式控制PC构建的通信管理装置的设计和实现过程。该装置具有以太网接口、CAN现场总线接口及8路标准异步串行接口，可以灵活应用于控制系统中的各个通信环节，实现异种网络间的通信协议转换和数据管理功能。该装置运行可靠性高、组态维护简捷，并且支持客户二次开发通信驱动程序。     

基于CAN总线监控系统设计

从分析CAN总线控制系统的设计思路人手,着重讨论设计中的主要问题,采用RS-485／422辅助CAN总线的混合总线结构,选用C8051F系列单片机和USB转UART桥接器CP2102作为控制核心,设计了一种多主、多功能的混合式总线监控系统。试验表明：该系统成功解决了数据传输瓶颈、数据冲突、同步等一系列问题,具有良好的实时性和稳定性,广泛适用于各类远程大型实时监控网络。     

SJ-30通信管理装置的设计和实现

由于Linux在可靠性、开放性等方面表现的特点，在嵌入式系统领域正获得愈来愈广泛的应用。本文介绍了一种采用嵌入式Linux操作系统和PC／104嵌入式控制PC构建的通信管理装置的设计和实现过程。该装置具有以太网、CAN现场总线等接口及8路标准异步串行接口，可以灵活应用于控制系统中的各个通信环节，实现异种网络问通信协议转换和数据管理功能。该装置运行可靠性高、组态和维护简捷、并且支持客户通信驱动程序二次开发。     

巨型水电站机组辅助设备自动控制一体化设计

随着以太网的高速发展,基于以太网的工业总线协议应用越来越成熟。Modbus TCP/IP技术更以其稳定、准确、实时的特点得到了全面的普及。经研究提出一种基于Modbus TCP/IP工业以太网的交叉热备冗余通信的巨型水电站机组辅助设备自动控制一体化设计方案,用于取代通过硬接线实现机组LCU与各辅助设备之间通讯的控制方式,这种设计经济可靠,技术先进,故障点少,接线简单,避免了继电器、端子排等硬件触点接触不牢靠的缺点,具有较高的通用性和灵活性,有效提高了巨型水电站综合自动化运行的可靠性。     

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.     

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.     

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。     

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。