600MW发电机转子匝间短路及接地故障分析

利用发电机内电势E和转子励磁电流If之间的函数关系,分析并总结了发电机转子匝间短路和转子接地故障的判据,通过对四川广安发电有限责任公司600MW机组发电机转子匝间短路和转子接地故障前、后数据分析和转子抽出后实际检查情况,印证了该判据的正确性。提出了转子接地的运行防范措施,以提高运行人员故障分析能力。     

水轮发电机组转子轻微偏心时的电磁性能分析

发电机转子发生偏心时,定转子之间会产生周期性不平衡电磁力,气隙磁场也会发生较大的变化。针对加拿大某电站水轮发电机组转子轻微偏心时进行电磁性能研究,建立了水轮发电机在理想状态和偏心状态下的有限元模型,分析了额定负载下的磁场分布、气隙磁密及输出电压波形、电流波形等数据。通过对比得到发电机转子轻微偏心时的电磁性能,可为发电机转子偏心处理和诊断提供一定的理论依据。     

大型水轮发电机转子现场安装工艺研究

转子是水轮发电机的重要转动部件,其作用是产生磁场,主要由中心体、转子支架、磁轭和磁极等组成,通过主轴与下面的水轮机连接,转子安装的质量直接影响机组运行的稳定性。本文根据鲁地拉电站转子特点,详细介绍了扇形支架焊接、磁轭叠装、大力筋及磁极安装等工艺,阐述了转子安装过程中的质量控制难点、重点;通过鲁地拉电站转子安装,总结了大型水轮发电机转子现场安装工艺及技术控制措施,以期对类似大型水轮发电机转子现场安装提供参考和借鉴。     

某电站发电机转子引线烧损原因分析及处理

发电机转子的主要作用是形成磁场,定子切割磁场产生电动势。发电机转子工作电流为直流电,且电流较大,因此其转子引线接头部位的固定及搭接质量至关重要。若接引面出现问题会导致发电机失磁而非正常停机。以一起发电机转子引线烧损为例,通过分析烧损现象,得出转子引线连接问题是造成发电机引线烧损的原因,并给出了解决方案。     

乐昌峡3~#发电机转子绝缘故障的分析及处理

针对乐昌峡电厂3#发电机在运行过程中发生的发电机转子绝缘故障的问题,结合乐昌峡电厂的实际运行工况,对可能导致发电机转子绝缘故障的原因进行分析,发现导致发电机转子绝缘故障的原因是9#磁极线圈绝缘击穿,通过对9#磁极线圈的处理,发电机转子绝缘恢复了正常,发电机能正常并网发电且运行平稳。     

600MW水轮发电机转子磁极极间支撑件应用研究与优化

随着水轮发电机组设计制造技术的发展,机组的容量不断增加,发电机转子磁极的高度和重量也越来越大。作为在运转中保证转子磁极稳定的关键部件,磁极极间支撑件对转子磁极的安全运行起着举足轻重的作用。结合大型水电站水轮发电机转子磁极极间支撑件运行存在的问题,通过对梨园水电站600MW水轮发电机转子磁极极间支撑件的应用研究,优化改进磁极极间支撑件的设计、制造和安装过程,为大型水轮发电机转子设备的安全稳定运行提供了更加可靠的保证。     

发电机转子匝间短路故障诊断及处理

由于一段时间国内主要几大发电机制造厂家超负荷生产,设备工艺及质量出现较多偏差,适时发电机转子匝间短路故障呈高发频发状态,仅某电机股份有限公司生产的某型发电机就出现多台次转子匝间短路故障。本文通过介绍某电厂转子匝间短路故障现象、故障诊断方法,故障处理及原因分析,对故障处理的几个主要问题提出了看法,总结了经验,旨在供同类型发电机转子故障诊断分析及处理参考。     

龙滩电站发电机转子现场叠片工艺特点

发电机转子是水轮发电机组的核心部件之一，随着水轮发电机组的设计、制造向大型化发展，发电机转子已由过去的在工厂车间生产转至在工地现场装配。转子装配质量的优劣，对机组的安全、稳定运行至关重要，发电机转子现场装配程序繁琐，工艺复杂，装配方式随转子结构的不同而采取的工艺措施有所差异。本文重点叙述龙滩电站发电机转子现场叠片的工艺特点，为同类大型转子的现场叠片提供参考、借鉴和经验交流。     

锦屏一级水电站发电机转子磁轭装配工艺特点

发电机转子现场装配程序繁琐,工艺复杂,装配方式随转子结构的不同而采取的工艺措施有所差异.目前已建和在建的大型水电站发电机转子磁轭多为整体结构,而锦屏一级水电站发电机转子磁轭则为两段结构.叙述了该电站发电机转子分段磁轭现场叠片的工艺特点,为同类型结构转子的现场叠片提供参考、借鉴和经验交流.     

水布垭水电厂发电机转子直流电阻故障处理

针对水布垭水电厂发电机转子直流电阻所出现的故障,通过排查影响发电机转子直流电阻的各个环节,分析试验数据,找出了故障的根源,提出了处理措施,顺利地排除了故障,保证了发电机安全稳定运行。     

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。     

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.     

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。