基于粒子群算法的灌溉水泵系统优化设计与运行

文章提出了一种相对较新的用于灌溉抽水系统优化设计和运行的管理模式。该管理模式利用粒子群优算法化建立并求解了一个两步优化模型。新提出的模型通过对所有可行的泵机组组合进行详尽的枚举搜索后,在所需时间段内处理给定的需求曲线,然后调用粒子群优化算法搜索每个集合的最优解。在优化机组的运行问题后,计算所有机组的运行总成本和初始投资折旧,确定最优的机组组合,并制定相应的运行策略。研究将所提出的模型用于实际泵站系统的设计和运行后,将结果与优化算法的结果进行比较。结果表明,所提出的模式与粒子群优化算法相结合是一种用于实际灌溉泵系统设计和运行的通用管理模型。     

基于进制数的水电站机组优化运行算法

机组组合是水电站短期发电计划中一个重要的问题,合理的组合运行能带来显著的经济效益。采用进制数编码形式表示机组的运行状态,以给定的负荷为基础,对机组运行进行优化,存储运行状态少,且最优方案不受初始值的影响;采用M atlab语言编写了电站内全局的最优机组组合及机组间负荷的合理分配程序,并给出了计算程序。实例计算结果表明:利用进制数的优化算法在机组组合优化问题上是可行的,也是有效的,该算法的收敛性好且速度快,对多机组电站的经济运行具有较好的实用价值。     

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。     

基于二进制和声粒子群算法的电站经济运行问题研究

机组组合是电站经济运行问题中典型的复杂非线性优化问题,其求解难度随系统规模增大呈非线性增长,如何对其进行高效求解一直是电力系统研究领域的热点和难点问题。为此,提出一种适用于电站经济运行中机组组合问题的二进制和声粒子群算法(BHSPSO):首先将粒子群算法的信息共享机制纳入到和声搜索算法的和声记忆库考虑操作中,并利用全局极值实现音调微调;然后采用启发式智能调整策略处理时段关联型约束条件,即根据机组优先顺序修复旋转备用约束,在此基础上,设计了一种“开-停-开”的修复策略处理最小开停机时间约束,有效改善了优化计算结果质量。将该方法分别应用于电站10台机组(简称10机)至电站100台机组(简称100机)系统标准算例,仿真结果表明:所提算法具有简单高效、收敛速度快、鲁棒性强等优点,为水、火电机组组合优化运行问题的高效求解提供一种新的途径。     

大型泵站进水前池复杂流态下机组启动组合优化

为解决杭州三堡泵站同时受正向和侧向进水水流影响的问题,建立进水建筑物二维数值模型,通过数值模拟计算不同机组启动组合和泵站前池的流场,以此评价前池水流的均匀性,分析涡流、脱壁等不利水流状态。通过提出泵站运行时不同台数机组的最优组合,以提高前池运行的平稳性、泵站机组设备的安全性。计算结果表明,采用二维数值模拟进行分析的研究方法可行,对大型泵站前池复杂流态下机组启动组合优化有一定参考价值。     

大规模系统月度机组组合和安全校核算法

采用时序优化方式解决月度机组组合和电网安全校核问题，针对电力市场和节能调度模式，建立了优化数学模型。利用拉格朗日松弛算法进行月度720时段机组组合优化，利用非线性内点最优潮流算法进行电网安全校核。以IEEE RTS标准算例和中国华东电网为例进行大规模优化性能分析，结果表明该算法是解决大规模电力系统月度发电计划和电网安全校核的有效方法。     

水电厂经济运行双层逐步优化法(TLPOA)研究及应用

笔者将双层逐步优化算法用于解决与水电厂经济运行有关的机组间负荷分配及机组最优组合的问题,经棉花滩水电厂的实际运行数据与该算法优化分配方案的计算成果比较,表明该算法可取得较好的经济效益.     

机组在线运行优化系统及实时目标工况的确定

介绍了机组在线运行优化系统的体系结构、数据流程和功能模块，提出了机组运行目标工况的定义和实现方案。采用基于趋势提取的检测方法对机组历史运行工况数据库进行稳态判定，将运行不可控因素作为约束条件运用K-均值法将机组稳定运行工况聚类到不同的工况簇中，以机组供电煤耗作为评价基准对各工况簇中的工况进行寻优，将各工况簇中的运行最优工况组合起来作为训练样本，建立起机组运行目标工况的神经网络模型，在进行实例验证后对模型进行分析讨论。实际应用表明，模型能够及时跟踪机组的运行特性变化，实时确定机组目标工况，对于提高机组经济运行水平具有现实意义。     

双层耦联遗传算法求解流域梯级水电站厂内经济运行问题研究

针对梯级水电站厂内经济运行调度模型约束条件多、求解复杂的问题,提出了一种基于遗传算法的双层耦联求解算法,该算法兼有机组负荷分配和机组组合双重优化的特点,可同时求得厂内经济运行优化调度模型的全局最优解.研制开发了基于此算法的梯级水电站厂内经济运行优化调度程序软件,并且已应用于某流域梯级水电站厂内经济运行实际调度计算中,取得了较高的工程应用价值.     

多阶段输电网络最优规划的并行蚁群算法

多阶段输电网络最优规划是一个复杂的非线性组合优化问题，难以采用传统的数学优化方法求解。蚁群算法是近年来出现的用于解决组合优化问题的一种高效的内启发式搜索技术，但存在着未成熟收敛问题。文中给出了多阶段输电网络最优规划的数学模型及其解的向量形式；详细分析了传统蚁群算法的未成熟收敛现象及其原因；提出一种并行蚁群算法并用于求解多阶段输电网络最优规划问题。并行蚁群算法无需初始可行解，能很好地协调局部搜索与全局搜索，在加快计算速度的同时有效地避免了因参数设置、种群规模等不同而引起的未成熟收敛。对实际算例的计算结果表明，该方法具有很高的计算效率和良好的全局收敛性。     

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。     

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.     

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.     

浙江省水域调查录入系统的设计和应用

浙江省水域调查录入系统将调查数据与电子地图相整合,对分类水域数据进行统计计算,并对输入数据进行合理性和完整性检查,得到调查范围内现有水域的详细数据,实现了水域调查数据输入、计算、统计和查询的数字化管理,提高了工作效率和工作质量,为各地下阶段水域保护规划编制和水域管理工作提供了数据支持。对该系统的设计原则、功能和技术设计等作了介绍。     

基于CT-连续加荷水泥乳化沥青混凝土细观损伤规律研究

利用CT技术对水泥乳化沥青混凝土的细观损伤过程进行实时扫描观测,获得了混凝土试件在连续加荷下的CT图像。通过采用直观分析法、CT数分析法、CT数与损伤变量关系3种方法分析表明,水泥乳化沥青混凝土的破坏过程可分为压密、扩容、裂纹扩展、破坏4个阶段,同时混凝土在受压过程中具有韧性,在极限荷载之前各断面处于压密和微扩容的强化阶段,极限荷载之后混凝土从损伤到破坏发展比较平稳。     

Automated system for removal and pneumatic transport of fly ash from electric precipitator hoppers

A system for removal and pneumatic transport of fly ash is examined, in which air pulses act on batches (pistons) of ash formed in a duct. Studies are made of the effect of several physical parameters on the force required to displace a piston of ash and these serve as a basis for choosing a system for removal and pneumatic transport of ash simultaneously from several hoppers of an electric precipitator. This makes it possible to separate the ash particles according to size without introducing additional components. Formulas are given for calculating the structural and dynamic parameters of this system and measurements of indirect dynamic parameters are used to calculate the input-output characteristics of the system. In order to optimize the system, configurations for summing several ducts into a single transport duct for pneumatic ash transport are proposed. Some variants of dry ash utilization and the advantages of producing of size-separated particles are considered. __________ Translated from élektricheskie Stantsii, No. 2, pp. 26–30 (2008).     

The flood pulse advantage and the restoration of river-floodplain systems

The ‘flood pulse advantage’ is the amount by which fish yield per unit mean water area is increased by a natural, predictable flood pulse. Evidence for this increase is presented from tropical and temperate fisheries. It is argued that increasing multispecies fish yield by restoring the natural hydrological regime is consistent with increasing production of other trophic levels and with restoration from ecological and aesthetic viewpoints. When applied to a river-floodplain system, this restoration would provide a large, self-sustaining potential for recreation, commercial exploitation, and flood control. An interim ‘natural flood pulse’ restoration approach is proposed for systems modified for navigation. This approach approximates the natural hydrological regime in a river reach and is intended as a first step in the long process of restoring the watershed.