抽水蓄能机组电力系统稳定器的应用

介绍了抽水蓄能机组励磁系统的特点,以及电力系统稳定器在抽水蓄能机组的应用。通过现场试验检验抽水蓄能机组PSS的性能以及发电工况和抽水工况的适应能力。     

国网电科院大型抽水蓄能机组励磁装置投入示范运行

2008年11月14日,国网电力科学研究院电控研究所承担开发的“大型抽水蓄能机组励磁装置”在河北潘家口蓄能电厂一次投运成功,并投入示范运行。该抽水蓄能励磁设备不仅满足了蓄能电厂原有的“发电工况”、“抽水工况”、“发电工况下投入PSS”、“背靠背启动工况”、“变频器启动     

大型抽水蓄能机组励磁系统设计

抽水蓄能电站承担调峰填谷、调频调相、事故备用和蓄洪补枯等多重任务,具有运行灵活、反应快速的特点,在智能电网的建设中发挥着重要作用.文中介绍了大型抽水蓄能机组励磁系统控制功能和各主要组成装置的设计原则,为大型抽水蓄能机组励磁系统的设计提供参考.     

可变速发电电动机交流励磁技术路线探讨

介绍了可变速抽水蓄能机组采用的交流励磁方式的原理,对在抽水工况和发电工况下交流励磁的优势进行了分析,对国产化交流励磁装置的技术路线进行了探讨。     

广州抽水蓄能电站励磁系统流程分析

在可逆式抽水蓄能机组中,励磁系统承担着重要的调控作用。励磁系统需要与监控系统、调速系统等在流程上进行紧密配合,以保障抽水蓄能机组能够安全可靠、快速有效地启停及运行。本文以广州抽水蓄能电站励磁系统为研究对象,探讨其在发电、拖动及电制动等多种工况下的控制流程,分析各部分励磁系统控制流程的合理性和必要性。通过广州抽水蓄能电站实际运行情况,探讨该励磁系统能否及时响应各阶段的外部信号,准确完成各步流程。     

黑麇峰抽水蓄能电厂背靠背启动过程分析

目前大型可逆式抽水蓄能机组在水泵工况启动时,可以采用静止变频器(SFC)启动和背靠背(BTB)启动2种方式。正常情况下机组采用SFC启动方式,在SFC故障或者检修维护时采用BTB启动方式,本文着重介绍了黑麋峰抽水蓄能电厂机组背靠背启动过程中监控、调速器、励磁控制流程,并对调试中出现的问题进行了综合分析。     

大型抽水蓄能机组同步控制回路设计

鉴于大型抽水蓄能机组运行工况和工况转换多而复杂,涉及到机组同步并列的工况转换也较多,机组同步控制须考虑机组各种运行工况下的需求,同步控制回路设计既要提高回路可靠性,更要保证控制安全性,论述了大型抽水蓄能机组同步方式及同步点选择、控制回路设计原则,机组同步控制过程等内容,并给出一个典型抽水蓄能电站的同步控制设计。     

大型抽水蓄能机组励磁系统的控制策略分析

分析了抽水蓄能机组的运行方式,介绍了抽水蓄能机组励磁系统的特殊性,从电动机负载运行、掏低频振荡的稳定控制、四象限无功控制、静态变频启动等4个方面论述了提高发电机运行及电网稳定的励磁系统控制策略。     

机组发电启动过程中励磁装置故障跳机分析

简要分析了潘家口蓄能电厂3号抽水蓄能机组发电工况启动过程中,由于励磁装置转子过电压动作导致启动失败的原因,提出相关的处理措施。     

十三陵抽水蓄能电站机组励磁系统

本文介绍十三陵抽水蓄能电站励磁系统的结构、参数、功能以及机组开，停机过程励磁的操作程序，从而可以看出抽水蓄能机组励磁系统及操作方式与常规水轮机组的差异。     

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。