地区电网保护定值校核专家系统的研究

应用专家系统理论及智能化程序设计方法，研制了一个可用于地区电网继电保护定值校核的专家系统：包括电网单线图动态显示、电网参数动态修改、短路电流计算以及保护定值校核等四个模块。采用TurboProloｇ语言中的模块化编程方法，将上述功能模块连接为一个有机系统并在IBM-PC/XT上进行了仿真试验。结果证明该系统具有较好的专家行为，可完成预期功能。     

基于保护整定值判别的电网故障自动生成系统

介绍了一个基于保护整定值判别的电网故障自动生成系统，包括电网接 线分析、短路计算和报警信息生成三个部分。在该系统中，由于每个保护是否动作是由保护 的整定值与短路计算值相比较的结果决定的，故能准确地模拟实际电网保护的动作情况，使 仿真效果更加逼真。     

基于Internet/Intranet的电网继电保护及故障信息管理系统

为提高电网事故分析的水平及继电保护和故障录波器等设备的管理水平，提出了基于Internet/Intranet 的电网继电保护及故障信息管理系统。该方案采用标准的保护通信协议及基于消息队列的传输平台，采用Web的发布形式。最后对继电保护信息系统中的常规应用和高级应用如定值核对、故障测距等提出了应用展望。     

主设备保护整定系统的设计和开发

主设备保护整定计算是发电厂变电站继电保护工作的主要内容。国内外主设备保护装置尚无统一典设，现场中采用的保护装置类型繁多，保护整定量大，传统的整定计算费时。文中针对主设备保护整定计算相对滞后的状况，给出了通用的主设备保护整定计算系统的设计方案，从整定系统的总体设计、各模块的功能、开发中采用的技术要点等方面进行阐述；提出了将故障仿真与整定计算相结合进行灵敏度校核的思想，确保了定值整定的合理性；在系统中应用自适应算法，充分保证了定值计算的高效率及计算结果的可靠性。     

界面图形化的电力系统短路计算智能系统

介绍了一个已在某电网投入试运行的界面图形化的短路计算智能系统。 它以电网拓扑结构数据库为基础，采用了图形界面和人工智能的广度优先搜索技术。该系统 人机界面友好，使用方便，电网运行方式和故障设置灵活直观，计算结果准确，是电网继电 保护定值计算和故障分析的良好工具。     

微机保护不停电整定配置的功能及其应用

为推动微机保护远方不停电整定定值等运行参数配置的广泛应用，阐述了3种支持系统的实现方案，这3种方案均在实践中证明了其实用性;探讨了运行中整定定值的安全考虑。研制的支持系统均在厦门地区电网稳定运行，大规模实施不停电整定。还实现了定值定期自动校核、软压板远方在线投切、保护信号远方复归、定值运行区远方在线切换等，对电力企业经济效益的提高和安全生产具有积极的推动作用。     

高压电动机综合保护整定计算的探讨

简要叙述高压电动机微机综合保护功能判据，重点探讨综合保护的整定计算原则。其中对电流速断保护在电动机启动后定值是启动时定值一半的原则，FC回路负序过流考虑断相后的保护定值，提出了不同看法。对过热保护、堵转保护、过负荷电流保护等定值的计算，根据实际运行经验，探讨了其较为合理的计算方法，最后对综合保护提出了进一步完善的改进意见。     

复杂三维流动数值模拟的非重叠区域分解法

本文从SIMPLE-C方法出发，采用基于非重叠子区域的Dirichlet-Neumann交替算法，提出了一种计算复杂三维区域内汉体流动问题的分区并行计算方法和通用程序，并以已有的算例为对照，验证了本方法的有效性，从而展示了本方法应用于工程实际中大规模复杂三维区域问题的分区并行计算的可行性和潜力。     

考虑多分区无功电压优化的多Agent系统

针对电网分区管理的特点，采用以管理分区为计算单元的新的三级组织结构，将管理分区与优化分区有机结合起来，构建了多Agent系统。采用分解协调模型和辅助问题原理作为多Agent系统的算法，各分区并行计算，通过数据驱动的模型进行多Agent间的协商、协调，完成全网优化计算。文中以枣庄地区电网为例，建立了该系统的优化运行机制以及对现有多分区系统进行无功优化的方法。实际应用表明，该系统比不考虑多分区的优化方案加快了优化速度，降低了网损，提高了电压水平，为多Agent系统在大型电网无功电压优化中的应用提供了更加实用化的解决方案。     

大电网分布式自适应继电保护系统的实现方法

从控制系统的角度，基于模式识别原理和扰动域的概念研究了大电网分布式自适应继电保护系统的实现方法。根据电力系统的固有分散性，提出了利用各级调度部门计算机构成分布式计算机系统，利用厂(所)计算机和厂(所)管辖的继电保护装置构成分布式子自适应控制器，并将它们有机地结合起来构成大电网分布式自适应继电保护系统。根据扰动域的概念，提出了计算机系统对子自适应控制器的局部控制方式。基于模式识别原理，介绍了将电力系统运行方式变化变换成相应的运行模式的方法，在此基础上，提出了扰动域内子自适应控制器的整定值按模式离线计算、分散存储、在线运行的工作机制。这种分布式自适应继电保护系统具有在线整定计算速度快、所需存储与交换信息量少、可人工干预自适应继电保护系统的整定计算过程、在线整定计算速度与电网规模基本无关等特点。     

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。     

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.     

基于BP神经网络-马尔科夫链模型的隧道围岩位移预测

在隧道工程施工中,围岩位移预测起着很重要的作用。将BP神经网络-马尔科夫链模型引入到隧道围岩位移预测中来,通过对训练样本的学习,利用BP神经网络实现了对位移时间序列的滚动预测,同时得到了实测值与预测值的相对误差;在此基础上利用马尔科夫链对相对误差进行修正,有效地提高了预测结果的精度。并将该模型应用于某公路隧道拱顶下沉位移时序预测中,结果表明该模型具有精度高、科学可靠的特点,为隧道围岩变形的预测提供了新的途径。     

Short communication. Pipelines as a refuge for freshwater snails

In the lower River Murray, Australia, populations of gastropods have declined markedly over the past 40 years. Of the native fauna of about 18 species, only the ancylid Ferrissia petterdi remains common (but in patches), and another five species feature in sporadic local resurgences. Until recently the viviparid Notopala was thought to be extinct. The introduced physid Physa acuta is widespread, but in low numbers. The decline probably is associated with flow regulation, high turbidity and the introduction of common carp. Snail populations have persisted, however, in irrigation pipelines fed from the river, where they periodically cause blockages. This paper reports the discovery of the only known populaion of Notopala hanleyi in a pipeline where the inner wall accumulates microbial and other organic matter, providing high quality food for snails. In the Murray before regulation most of the periphytic biomass was probably microbial, as fluctuating water levels would have maintained littoral communities in a highly productive, early state of succession his postulated that, by stabilizing seasonal water levels, regulation has promoted the production of filamentous green algae, an inferior food source, and so displaced snail populations from the open aquatic environment.     

Spatio‐temporal variation of gross CO2 and CH4 diffusive emissions from Australian reservoirs and natural aquatic ecosystems,and estimation of net reservoir emissions

Carbon dioxide (CO₂) and methane (CH₄) diffusive emissions were measured during two field surveys in Queensland and Tasmania, Australia, using the floating chamber method. Bubbling and degassing emissions in 2010 were estimated in Koombooloomba Dam reservoir using only inverted funnels and gas concentrations, respectively. A total of 14 reservoirs and 16 rivers and lakes were sampled from 2006 to 2010. Spatial variation was substantial within each water body, as well as between them. The main drivers of diffusive emission variation were physiographic region and climate, with a clear demarcation being observed between diffusive emissions from tropical Queensland and temperate Tasmania, and between the humid West Coast Range (Tasmania) and dry Central Plateau (Tasmania). Higher CO₂ and CH₄ diffusive emissions were observed during the dry season, when long water residence times would promote organic matter degradation. Estimated total gross emissions, including diffusive, bubbling and degassing emissions, for Koombooloomba Dam reservoir were about 1.5 × 10⁶ t CO₂eq km² per year, or 24 × 10⁶ t CO₂eq per year. This corresponds to a plant emission factor of 3.18 kg CO₂eq MWh^?1. Using an estimate of terrestrial emissions derived from literature data for the Tully River catchment area, rough estimated net emissions from the catchment area are about 44 kt CO₂eq per year, or 5.83 kg CO₂eq MWh^?1, which is in the lower range of the studied reservoirs.