水布垭电厂调速器控制系统运行中的几个问题及对策

介绍了水布垭电厂调速器控制系统投运以来出现的重大问题,详细分析了故障原因,提出了解决办法,为水电厂调速器系统的调试、维护提供了参考。     

水布垭电厂调速器压油系统控制及维护分析

简要介绍了水布垭水电厂调速器压油系统电气控制原理,在实际运行过程中程序的完善以及对卸载和软启动过程的探讨。     

水布垭水电站三微机调速器的技术改造

介绍了水布垭电站三微机调速器的总体结构、运行状况和技术改造情况。针对历年来调速器运行暴露出的各类重大隐患和缺陷,对调速器系统进行了多项技术改造,保障了设备的安全稳定运行,也为其他水电厂调速器的改造完善提供了有益参考。     

清江水布垭水电厂设备巡检系统的开发与应用

本文通过对水电厂设备巡检发展趋势的分析比较,阐述了开发设备巡检系统的可行性、必要性,详述了水布垭水电厂设备巡检系统的软硬件组成、操作方法和实现过程。随着Code-39、B/S结构、ASP.NET、SQL Sever2000等新技术在水布垭电厂设备巡检系统中的应用,该巡检系统成功替代了过去手工抄表的巡检方式,提高了工作效率和效果,积累了一大批宝贵的电厂设备状态数据。     

黑启动在王甫洲水电厂中的应用与探讨

首先介绍了王甫洲水电厂,阐述了黑启动的意义,进而从调速器、励磁、辅机系统、直流系统、监控系统详细分析了水电厂黑启动,提出了水电厂黑启动方案,最后根据黑启动在王甫洲水电厂中的应用,提出了黑启动过程中需要注意的问题。     

某水电厂调速器系统溜负荷事件的分析与处理

调速器系统溜负荷是水电厂机组比较常见的一类问题。介绍了某水电厂一起调速器系统溜负荷事件的经过,通过检查调速器系统及机组运行数据,分析了事故的原因:导叶行程传感器连杆因焊接处断裂而松动。论述了故障处理方法,并提出预防控制措施。     

水电厂自动化技术30 年回顾与展望

主要回顾了自动化所成立30年来在水电厂计算机监控系统、水情测报系统以及调速器技术等领域的发展和变化历程。详细介绍了H9000系列水电厂计算机监控系统,特别是H9000 V4.0系统在三峡右岸机组上的顺利投入运行,是我院水电站监控技术进步的一个重要标志;应用卫星、GSM技术在水情测报系统的广泛应用,已由单站向流域的发展,不断开发新产品,特别在防雷技术、中继站技术等方面取得重要成果;介绍了调速器技术研发的历程,特别是快速开关阀与逻辑插装阀组件在水轮机调速器中的成功应用,是调速器技术一项革命性的变革,为调速器的发展带来了新的空间和活力。     

察尔森水电厂发电机调速器改造论证

文章结合察尔森水电厂调速器系统YDT-3000A在运行中存在的问题,提出了调速器改造方案可行性研究论证。     

桃林口水电厂调速器改造及应用

桃林口水电厂原来采用的是微机电液转换YDT—6500型调速器,此调速器运行中经常出现电液转换器卡阻、主接力器抽动等现象,不能实现自动运行。根据水电厂多年积累的实际运行经验,综合考虑设备的先进性、合理性、运行环境的配套、与监控系统的通讯等各方面因素,确定采用PCC数字阀调速器。经实际应用,此调速器运行稳定,动作灵敏可靠,保证了水电厂的安全运行。     

水布垭电厂调速器切换阀换型及液压控制系统管路改造

为避免调速器切换阀出现机械零点飘移造成机组开机失败及在运行过程中出现溜负荷现象,对水布垭电厂4台机组调速器切换阀进行换型并对液压系统管路进行改造,提高了设备安全稳定性能。     

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.