苏丹麦洛维电站1F/2F/6F机组变负荷试验研究

通过对比分析苏丹麦洛维电站1F/2F/6F机组变负荷试验,检验了2F转子中心体裂纹的修复的效果;对比分析出现裂纹和未出现裂纹机组的稳定性指标,对出现裂纹未修复的1F机组和未出现裂纹的6F机组也进行了变负荷试验,指导机组的后续修复和运行。划分了1F/2F/6F机组在全负荷范围的稳定运行区域,并找出了各运行区域的主要频率。试验成果有助于麦洛维电站机组及电网的安全运行。     

区域电网机网协调系统调试方案研究

随着电力体制改革的进一步深入,多个地区都建立了区域电网,区域电网的安全稳定运行对各地区和企业的经济社会发展具有重要作用。为了确保区域电网的安全稳定运行,需要进行区域电网安全稳定性试验,某区域电网机网协调系统试验就是该电网的安全稳定性试验。笔者通过介绍某区域电网的机网协调系统的结构、配置和功能,以及机网协调系统试验的目的、步骤、风险、安全措施和注意事项,形成具有可操作性的区域电网安全稳定性试验方案。该方案对于区域电网安全稳定性试验起到一定的参考作用。     

三峡电站右岸21号机组启动试运行试验研究

文章简要小结三峡右岸21号机启动试运行试验。发现了21号机在高负荷区的转频频率振动，检验了厂家保证值，划分了21号机在全负荷范围的稳定运行区域。试验成果有助于右岸ALSTOM机组及电网的安全运行。     

刘家峡水电厂1号机转轮更换前后稳定性分析

阐述了刘家峡水电厂1号机转轮更换前后机组的稳定运行情况,介绍了1号机原转轮叶片裂纹情况、补焊修复措施,并根据转轮更换前后机组稳定性试验数据,分析了机组在不同负荷区域的稳定性能。     

660MW机组W形火焰锅炉燃烧优化调整

针对某电厂660MW机组W形火焰锅炉燃用煤种与设计煤质偏差较大、锅炉效率偏低的问题进行了燃烧优化调整试验。首先通过调整F挡板对省煤器出口氧量分布进行调平,然后从影响锅炉运行经济性的主要因素入手,结合该锅炉的特点,分析了负荷变化、二次风变化、煤质变化和C挡板开度等参数对锅炉效率的影响,指出了合理的运行工况。     

试论恰甫其海水轮机的运行

介绍模型转轮试验及见证试验的结果,分析水轮机主要特性对其运行的影响。对各运行区域的特点及其运行的要求进行了论述。根据实际运行情况,对改善运行区域的条件进行探讨。     

南桠河发电厂2号机组副机稳定性试验及处理

针对南桠河发电厂2号机组存在机组轴线弯曲及其所带副机摆度幅值偏大的问题,提出了稳定性试验的方案;根据试验结果,分析和处理了副机存在的动不平衡,达到了改善改造后机组稳定运行的目的,最后,对该机组的安全稳定运行提出了建议。此次试验成果对同类机组副机的改造具有借鉴意义。     

双排机水电站运行特性研究

目前有关双排机水电站运行规律的研究十分缺少,现根据世界第一大双排机水电工程——李家峡水电站双排机真机试验所取得的振动与脉动原型观测资料,对双排机水电站的运行稳定性特点进行分析.分析了同一排布置的上下游机组单机运行时的差别,并着重分析了在不同负荷组合下双排机联合运行的特性,得出了一些有利于指导工程运行的结论.     

示踪法对小浪底坝区绕坝渗漏通道的研究

小浪底水库运行以来,左坝肩的渗漏水量偏大,当库水超过235 m高程时,排水量急剧增加.将库水中D,18O,3H作为"事件"示踪剂,用来进行绕坝渗流场及渗漏通道的调查,配合人工示踪、连通试验等方法,查清渗漏水补给来源、渗漏层位等.天然示踪试验和连通试验证实:左坝肩帷幕下部的T3-11中存在强渗漏,库水入渗到T14,T13-1透水层,然后通过F28,F235,F238等断层补给到深部的T13-1,最后由揭露该地层的30#排水洞排出.     

滩坑水电站1号机组振动区试验研究及分析

滩坑水电站作为区域负荷的调峰调频电站,保证机组的稳定运行具有重要意义。为划分1号混流式机组的安全稳定运行区域,通过真机试验的方法对机组进行了典型水头下的变转速、变励磁和变负荷试验,试验结果表明机组的整体运行稳定性良好,最终将机组的运行区域划分为小负荷区、涡带工况区和大负荷区。     

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。     

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.     

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。