计及气候、含风力发电的配电系统可靠性评估研究

分布式电源（distributed generation,DG）的接入使配电系统从辐射型的网络变为遍布中小电源和用户的互联网络,将对传统配电系统产生巨大的影响。而风力发电机（wind turbine generation,WTG）凭借其无污染、建造费用低、发电灵活等优势越来越多地被作为分布式电源接入配电网。但由于其自身功率输出随机性强的特点,对传统的分布式电源接入配电网带来了一定的影响。在充分考虑了气候因素对WTG功率输出和配电网馈线故障率的影响的同时,结合WTG的多状态模型与配电网孤岛运行方式,对含有气候因素并以风力发电机作为分布式电源的配电系统的可靠性评估情况进行了阐述,希望电网规划人员在选择最优方案时能够考虑由上述因素带来的影响。     

含分布式电源的配电网综合优化方法研究

讨论了不同位置和容量的分布式电源并网后对配电网的影响,对含有分布式电源的配电网络无功优化进行了研究。采用改进遗传算法,以综合经济效益最大为目标函数,将配电网中分布式电源选址定容与电容器投切相结合进行了综合优化。实例分析结果表明,该方法能够同时实现配电网络中分布式电源最优配置和配电网无功优化,从而有效降低配电系统损耗、改善电压质量,获得更好的综合经济效益。     

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。     

多目标微网环保经济调度模型研究

微网运行特别是在孤岛情况下,由于太阳能光伏发电、风力发电的随机性较大,使得其电能的调度成为一个重要且困难的问题。针对不同分布式电源的特性以及成本,对传统意义下的微网经济调度模型进行了修正,将环境成本、发电成本和旋转备用成本作为多目标,建立了环保经济的微网多目标模型。针对3个不同的目标函数,采用NSGA-II多目标优化方法,求解多目标协调的最优解。算例结果表明,该算法和模型的收敛更快、更全面。     

多目标微网环保经济调度模型研究

微网运行特别是在孤岛情况下,由于太阳能光伏发电、风力发电的随机性较大,使得其电能的调度成为一个重要且困难的问题。针对不同分布式电源的特性以及成本,对传统意义下的微网经济调度模型进行了修正,将环境成本、发电成本和旋转备用成本作为多目标,建立了环保经济的微网多目标模型。针对3个不同的目标函数,采用NSGA-II多目标优化方法,求解多目标协调的最优解。算例结果表明,该算法和模型的收敛更快、更全面。     

电力系统运行可靠性成本价值评估

电力系统运行可靠性评估的最终目标是辅助运行人员进行调度决策,因此,制定合理的决策依据至关重要,但常用的可靠性指标却难以直接作为决策判断的依据。文中提出了运行可靠性成本价值评估的概念和指标,指出“期望社会成本最小”可以作为运行人员选择最优调度方案的决策依据,并为此建立了发输电系统运行可靠性成本价值评估的模型和算法,实现了运行可靠性成本和效益的综合评价。通过对IEEE RTS测试系统的最优旋转备用分配方案选择的计算分析,验证了所述算法的有效性,说明了运行可靠性成本价值评估的实用价值。     

基于社会效益最大化的黑启动电源规划

通过论述电力系统恢复的步骤和策略,分析了黑启动电源对电力系统恢复的影响。建立了以社会停电损失最小为目标的黑启动电源规划模型,用以优化黑启动电源的安装位置及容量。模型考虑了2种情况,分别研究黑启动电厂对口支援非黑启动电厂和互联电网情况下黑启动电源规划问题,并考虑了用户停电损失率随时间变化的问题。应用遗传算法求解互联电网黑启动电源规划问题,并给出算例对所提出的规划模型进行了验证。最后总结了影响黑启动电源布置的因素。     

基于免疫算法的配电网开关优化配置模型

给出了开关优化的数学模型及基于免疫算法的求解方法。分析了开关投资和运行维修费用、停电损失的计算方法，基于等年值法建立开关优化配置模型。该模型是一含约束、不可微、非连续的组合优化模型。基于免疫算法给出了模型的求解算法。通过模型计算确定开关的最优配置数量和位置，并得到系统的可靠性、投资费用和停电损失等。计算实例表明：提出的模型和算法有较强的工程实用性，免疫算法具有较好的全局收敛性和较快的收敛速度。     

韩江下游水资源合理配置与管理初探

水资源配置经常要面临不同层次、不同目标、不同用户间的相互竞争,甚至相互冲突,为解决此类问题,需构建水资源配置模型．先用水文模拟模型进行流域水文模拟,分析流域水资源配置的各影响因子,将重要影响因子输入配置模型,配置模型根据环境、效率、公平等原则提出流域水资源配置方案,最后将方案输入水资源配置评价模型进行分析,评估流域水资源配置方案对流域可持续发展的影响程度,并依此做出合理的水资源配置。以韩江下游为例,对构建韩江下游流域水资源配置模型进行计算、模拟和评价,结果显示,可用水资源配置模型进行合理的水资源配置。     

含间歇式分布电源配电网的可靠性评估

智能电网是现代电网的发展方向,它要求未来的配电网能够自由接纳分布式电源（DG）。但DG（尤其是问歇性可再生能源分布式电源）具有分散、随机变动等特性,大量接入将对系统的安全、稳定运行产生极大的影响。提出了对风力、光伏发电等DG配电网系统的可靠性进行全面准确评估的新方法。建立了间歇式分布式电源（IDG）的可靠性模型,引入关联矩阵来处理孤岛的划分问题,介绍了含IDG配电网可靠性的评估方法。通过算例分析DG对配电网可靠性的影响机制,为多种能源互补的配电网扩展规划提供一定的参考。     

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。     

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。     

浅谈天湖水电站水轮机运行故障及处理措施

简述天湖水电站投运以来各种故障的表现形式，分析其原因，提出了相应的处理方法及措施，并对合理利用国内外设备提出建议。     

Fish assemblage response to recent mitigation of a channelized warmwater stream

Various designs of low‐head dams are used to rehabilitate streams or forestall upstream channel incision after channelization. We report on the efficacy of using notched sills and grade control structures (GCS) to restore the fish assemblage in Luxapallila Creek, Mississippi. We tested the null hypotheses that habitat variables and species richness, evenness, and assemblage structure would not differ among: (1) a channelized segment with no modifications; (2) a channelized segment mitigated by the installation of sills and GCS; (3) a segment upstream of the installations and undergoing channel incision; and (4) an unaltered segment. Although habitat variables changed, neither species richness, evenness, nor fish assemblage structure differed between mitigated and channelized segments with both exhibiting less richness and different assemblage structures than the unaltered segment. Lack of differences in species richness between the incised and unaltered segments suggest that the GCS may have halted the negative effects of upstream channel incision before species were extirpated. Conspicuous habitat differences between the altered (channelized and mitigated) and unaltered segments were lack of backwaters and canopy coverage and finer substrates in the altered segments. Our results suggest a more comprehensive rehabilitation strategy is required in Luxapallila Creek. Published in 2003 by John Wiley & Sons, Ltd.     

NUMERICAL STUDY OF WAVE EFFECTS ON SURFACE WIND STRESS AND SURFACE MIXING LENGTH BY THREE-DIMENSIONAL CIRCULATION MODELING

1. INTRODUCTION Coastal and continental shelf regions are characterized by intensive interaction between wave and current. These regions are of great economic significance to mankind. Therefore, the modeling of wave and current as well as their mutual int…