构建大电网安全防御体系——欧洲大停电事故的分析及思考

欧洲电网2006年11月4日大面积停电事故起源于德国电网内一条线路的停运。文中简要介绍了线路停运前系统的运行状态及事故的发展过程，多方面分析了产生事故的原因，指出了欧洲电网暴露的问题，总结了经验和教训，探讨了构建大电网安全防御体系的几个方面。     

海南电网“9·26”大面积停电事故的分析与总结

海南电网2005年“9·26”大面积停电事故是近年来中国第1次出现的由自然灾害引发的省级电网大面积停电事故，海南电网也同时成为中国第1次因电网大面积停电而实施黑启动并获得成功的省级电网。文中介绍了海南电网大面积停电事故的过程以及随后的黑启动情况，分析了事故原因及暴露出来的问题，总结了经验与教训，进而提出增强电网、抵御事故能力的措施与建议。     

电网停电事故的自组织临界性及其极值分析

对复杂电力系统灾变以及电网发生连锁性大停电事故机理的研究表明，自组织临界性是电网停电事故的特征。极值理论主要以极值为研究对象，传统上被用来预测海啸、地震、洪水等自然灾害。文中将极值理论应用于电网停电事故的自组织临界性的研究中，在电网停电事故的标度 — 频度幂律分布特征下，证明了停电事故发生规模的极值分布为极限收敛于Ⅰ型渐近分布。利用计算公式以东北及西北电网的停电事故为例，进行了初步的计算分析。     

暂态失稳引起大停电的可能性与对策研究

以某一将来实施分片运行的500 kV/220 kV规划电网为对象，从暂态稳定的角度对系统发生大面积停电的可能 性进行分析研究，并从电网规划、运行管理、继电保护和自动装置等方面，就预防大面积停电事故提出对 策。介绍了仿真计算所需的负荷模型、电源模型、输电线路模型、变压器模型等电网模型。     

浅析大花水水电站黑启动方案和孤网运行方式

黑启动是在电网发生大范围停电事故、电网崩溃瓦解的情况下迅速恢复供电的重要措施。本文介绍了贵州清水河大花水水电站黑启动方案和孤网运行方式，分析了成功黑启动的条件，并提出了水电站黑启动和孤网运行中存在的一些问题和解决方法。     

长潭发电公司“黑启动”方案分析与实施

自2003年8月14日起，短短几周内，美加、伦敦、悉尼、马来西亚出现大停电．中国北京西北部油罐车爆炸致京西北区域电网发生近百小时停电等等。为避免类似情况发生，根据广东省粤电集团和广电集团的要求，电网企业要制订电网发生稳定破坏事故后的应急预案和“黑启动”方案，编制了在电网系统事故停电时的“黑启动”方案。文章首先从电网所处的位置及容易造成厂用电消失的原因分析入手．详细地阐述“黑启动”方案如何在技术方面的实施。     

浅谈水电机组的黑启动技术

文章就最近一个时期以来，世界各国（包括我国）不断发生大面积停电事故，给人民生产与生活带来重大损失的沉痛教训，以及我国国电公司对大面积停电的应急预案的提示，提出如何利用水电机组的优越条件，对水电机组进行黑启动，以恢复厂用电及给系统送电，并激活电网各电厂投入运行，最后使整个电网恢复运行，做一些技术性探讨。     

电网“大停电”实施“黑启动”方案的分析

自2004年8月14日起，短短几周内，美加大停电、伦敦大停电、悉尼大停电、马来西亚大停电、中国北京西北部油罐车爆炸导致该市西北区域电网停电近百小时……为了避免类似情况发生，广东粤电长潭发电公司有限责任公司根据粤电集团和广电集团的要求，制订了企业因电网系统事故停电时的“黑启动”方案。本文从分析公司在电网所处的位置及容易遣成厂用电消失的原因入手，详细阐述了长潭发电公司实施“黑启动”方案的有关技术要点。     

电网运行停电风险概率函数构建研究

提高供电可靠性,减少停电事件是电力企业的工作重点,也是电力用户的迫切希望。掌握电网运行停电事件的发生规律,可以为电力企业制定提高供电可靠性的有效措施提供依据。基于此,结合概率论理论,提出了构建电网运行停电风险概率函数的新方法。根据某地区2008-2010年的停电事件统计数据,运用Matlab软件建立了该地区电网运行停电风险概率函数,并对停电事件进行了分析。实例验证表明:该建模方法有效可行,可以用于计算电网运行停电风险概率。本研究为评估电力用户停电损失做了前期准备。     

国家紧急布署电力安全和应急对策

近两年来，美、加大停电事故和俄罗斯莫斯科大停电事故相继发生，造成了严重的经济损失和社会影响。党中央、国务院对此高度重视，国务院领导做出了重要批示，要求国家发展改革委统筹研究电源、电网建设问题。近日国家发展改革委紧急召集全国各地、各大电网公司和电力生产企业共同研究电力安全和应急对策。     

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。