华北电网安全节能发电优化调度系统功能设计

华北电网安全节能发电优化调度系统采用与能量管理系统（EMS）一体化设计，可直接应用EMS采集的电网模型，并以此为基础进行拓扑分析。该系统采用分布式软件设计，便于开发、维护、实用。以安全约束机组组合为核心完成年度合同分解、月度合同分解、月度市场、日前调度等功能。这些功能在优化时考虑电网安全约束和机组的技术参数，保证优化结果真实可行。通过系统的研究态多时段交流全网络安全校核功能对优化结果进行校核，保证结果真实可行。实际应用表明该系统效果良好。     

一种计及静态安全约束机组组合的有效算法

以直流潮流模型为基础,将计及电网静态安全约束的机组组合问题分解为无安全约束的机 组组合问题和计及电网静态安全约束的优化潮流问题2个子优化问题。通过在后者中引入虚拟变 量来反映机组组合对输电元件传输限制的牵制及影响,并借用虚拟变量和发电转移因子,构建前者 与后者间关联的补充约束条件,从而形成前者随后者变化的影响机制及优化方向的修正手段,由此 提出了2个子优化问题间交替求解的算法。该算法充分兼容现有成型方法,符合电力系统实际,对 解决电网静态安全对机组组合制约现象,以及对机组组合方案评价,有良好的适应性。     

精细化日发电计划模型与方法

电网调度精细化管理水平的提高客观上要求日发电计划的精细化管理。针对传统日发电计划功能单一且难以实现准确的安全校核与网损管理的问题，提出了精细化日发电计划模型及优化算法。该模型以电网状态估计的网络拓扑和参数构造约束条件，决策目标兼顾电网经济性与安全裕度价值，具有应对电网运行不确定性的能力。采用交直流混合迭代优化算法，提出了交流潮流分析与有功优化的一体化决策方法，工程实用性强，有助于实现网损管理和安全校核工作的精细化管理。最后采用IEEE 30节点算例验证了算法的合理性。     

初期电力市场确定电网日发电计划的模型与方法

在日前交易未开放的初期电力市场模式下，如何针对其特点建立合理的日发电计划模型对于保证这一时期各市场参与者的利益具有重要作用。文中立足电网公司建立日发电计划模型，重点考虑了非竞价机组的经济运行成本，并计及了包括竞价机组年度和月度中标电量的日分解值、机组爬坡速度、旋转备用和线路有功传输限制等约束。在所建模型的基础上，通过改进二次规划的可行方向法，计算发电成本函数为分段二次函数的动态优化调度问题，并与一个启发式机组组合算法相结合用以确定日发电计划。算例结果表明，该模型及方法可行、有效。     

大规模水电站群短期优化调度方法Ⅱ：高水头多振动区问题

高水头多振动区是我国干流巨型梯级水电站群面l临的突出运行问题之一。由于水电站需要响应复杂的系统负荷变化,导致发电水头频繁波动且幅度较大,使得机组运行要频繁跨越多个不规则振动区,严重影响水电站群及电网的安全。针对此问题,提出了求解高水头多振动区的水电站群短期调峰优化方法。该方法以机组组合为基础,分别利用动态规划技术与组合数学理论生成各组合机组的发电特性曲线与振动区,并将振动区避开策略引入逐步优化算法未进行模型求解,较好地解决了高水头多振动区凋峰问题,能够高效地得到满足工程实际运行需要的计算结果,已在红水河等流域得到实际应用。     

电网安全节能发电日前调度优化模型及算法

华北电网安全节能发电调度辅助决策系统中的日前调度模块实现了机组组合和安全约束经济调度两大功能,制定日发电计划既符合各种安全约束又满足各类辅助服务需求。采用同一个优化模型,通过修改输入信息实现节能发电调度、电量进度发电调度、成本调度、市场竞争等多种调度模式。引入violation和violation penalty weights两类参数,确保优化模型始终有解,满足工程实际应用的要求。采用同时可行性测试与优化计算相迭代的方法缩短了计算时间。日前调度模型为混合整数规划模型,采用分支定界法进行求解。为了精确校核日前调度结果,该系统开发了研究态全网络多时段安全校核功能,选择多个时间节点对日前调度结果进行精确的交流潮流校核,确保日前调度结果满足安全运行要求。     

东北区域市场中长期交易安全校核改进方法

以东北区域电力市场年度合同交易、月度合同交易为背景，研究了这2种交易的安全校核和阻塞管理问题。针对当前方法的不足，结合中长期交易的特点，提出了采用线性优化模型对中长期交易进行安全校核。将断面输电电量作为优化变量，结合竞价优化目标，建立含安全约束的购电优化模型，在确定中标电量的同时进行安全校核和阻塞管理。针对线性优化模型无解的情况，提出二次优化的概念，第1次优化得到可行解域的优化模型，第2次优化采用第1次优化得到的优化解域获得最优解。从而保证了该方法可以在工程领域实际应用。     

市场环境下中长期发输电协调检修计划优化

根据电力市场环境中检修计划的特点，建立了协调市场各方利益的发输电一体化检修计划优化的数学模型，该模型综合考虑电力系统安全经济性和电力市场公平性，并考虑机组检修和输电设备检修之间的相互关联关系。针对该优化模型的求解，利用遗传算法（GA）和粒子群优化（PSO）算法相似的优化框架和优化流程，提出一种充分结合GA和PSO算法各自优点的混合智能算法，该算法将群体分成2个子群，分别采用GA和PSO算法进行演化，并充分交换2种算法所获取的优化信息，形成一个紧密耦合的、新型的遗传粒子群优化算法。算例证明，该算法在求解发电、输电设备检修协调优化这样的大规模复杂优化问题时，在全局搜索和局部搜索方面都表现出了良好的均衡性。     

基于电力系统日发电计划的混合智能messy遗传算法

机组组合是电力系统日发电计划中主要的优化任务，在满足各种约束条件下求得全局最优解是一个比较困难的问题。传统遗传算法的二进制编码和随机遗传操作不适合于求解大规模机组组合问题。针对电力系统日发电计划的特点，提出了一种混合智能messy遗传算法(HIMGA)，该算法实现简单，大大减小了求解问题的规模，保证了群体的多样性，提高了算法的搜索效率，改善了算法的收敛性。仿真计算结果表明了该算法的有效性和实用性。     

基于动态搜索线性混合整数法的机组组合新算法

针对常用机组组合算法计算量过大的问题，提出了一种基于动态搜索的线性混合整数规划法，该方法在基于分支的线性混合整数规划法的计算框架中引入了动态搜索的概念，采用单独考察与时间相关的约束和功率约束等措施来减少进入分支阶段的数量，在实际运用中，可针对不同规模的系统通过调节计算参数灵活地控制计算时间和计算精度。算例分析结果表明，该方法快速、有效，适合求解大规模电力系统安全约束机组组合问题。     

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.