VPN技术在广西电网水调自动化系统中的应用

针对广西电网统调水电厂目前的通信现状,叙述了利用虚拟专用网(VPN)通信技术实时传送雨水情信息的必要性和可行性.在简要叙述VPN技术的基础上,介绍了广西电网水调自动化系统VPN组网构造,通过实践应用,对比分析了互联网VPN通信与电力专用通道的优劣,说明VPN技术的应用合理地解决了广西电网雨水情信息实时传送的安全性、稳定性和经济性,为充分发挥电网水调自动化系统的作用提供了强大的网络通信平台.     

广西电网通信网应用拓展宽带载波入户组网方案

电力线宽带载波是一种新兴的用户终端接入手段。笔者针对广西电网现有通信网络资源情况,介绍宽带载波入户技术,结合广西电网自身结构特性,提出了多种技术融合的广西电网通信网宽带载波入户组网方案。此种组网方案业务流向清晰,结合广西其他配网光缆资源和电表安装空间,可满足现有居民用户的互联网接入,结合后期开发,可提供电网信息等增值服务。     

关于220kV变电站防误闭锁回路的几点思考

随着电网的不断发展,技术的不断更新,防误技术也在不断地改进和完善,防止电气误操作也逐步发展成为电力自动化技术的一项重要独立分支,成为保障电力安全生产的重要措施之一.变电站监控系统遥控操作必须有防误闭锁系统的保证才能发挥应有的作用,因此设计正确合理的电气闭锁回路对于防止电网事故具有非常重要的意义.     

调度自动化系统通道建设的探讨

电力调度自动化系统是电网运行和管理的基础性设施.我县电力调度自动化系统2001年5月投入使用后,在确保电网安全、经济运行、提高供电可靠性方面发挥了重要的作用,收到了显著的经济效益和社会效益.但由于我们在调度自动化系统建设中,只强调了主站和各子站功能的完善,忽视了通信通道建设,运行以来屡屡发生通信障碍,严重制约了调度自动化系统功能的发挥.     

从凝冻灾害影响探讨乌江公司通信系统的抗灾能力

贵州乌江水电开发有限责任公司（以下简称“乌江公司”）的通信系统以电力光纤为骨干进行组网,在2008年1月贵州发生50年一遇的凝冻灾害后,该公司通信系统几乎处于完全瘫痪的状态,则卫星通信在这次灾害中发挥了地面通信的容灾备份作用,及时接替了该公司重要生产实时信息的传输任务。通过这次凝冻灾害暴露出乌江公司通信系统的不足,必须将现有通信组网改为使用多条路径的光纤进行地面组网,并将卫星通信作为备用通道,增加互联网的IP电话,最大限度地保证公司各单位间的通信联系。     

广西省级电网光纤传输网络组网方案

光纤传输网是电网通信网络的支撑.文章针对电网传输信息业务的特点,介绍OTN、ASON多种光纤通信技术及组网方案,结合广西电网自身结构特性,提出了多种技术融合的广西电网省级光纤传输网络组网方案,并通过专项软件对组网方案进行了仿真分析和优化,为省级传输网络的建设提供借鉴和参考.     

铜芯通信介质在超高压环境中的实际应用

电力电网的输电电压大幅度增高，给通信造成的干扰也急剧增大。如何防止转移电位引起的危害和解决在超高压环境中的通信安全问题已成为电力工程技术设计及研究人员所关注的课题。漫湾水电站设计使用特种高压保护通信电缆和特种高压保护计算机电缆的情况，值得作简要的介绍。     

百色市中型水库(一)期水情遥测系统设计概述

介绍了百色市中型水库水情测报系统建设项目的背景概况,论述了水情遥测系统的通信组网方式,合理构建系统组成、安排信息流程、中心站遥测应用平台软件及遥测站RTU的特点.     

双网隔离框架下水调自动化系统 Web 功能实现

介绍了电力自动化系统隔离模型,分析了电力信息网络安全防护框架下水调自动化系统Web 功能部署的设计思路,提出了基于跨平台跨安全分区的解决方案,在青海电网水调自动化系统的基础上说明了 Web 功能的部署方式、网络架构、关键技术及应用前景,并阐述了运行过程的完善与优化方法.经现场实践证明,该方案设计合理,系统运行稳定.     

基于Mobitex的电力负荷管理系统设计

随着全国电网向现代化方向发展，对电力负荷管理系统提出了更高的要求，其中，通信网络的性能直接决定了电力负荷管理系统运行的可靠性和实时性。Mobitex无线数据专用网专注于高可靠性、短时间突发数据的实时通信，非常适合电力负荷管理系统。文中根据电力负荷管理系统对通信系统的要求，结合Mobitex无线数据专用网技术，提出了一种新型的电力负荷管理系统设计方案。     

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。     

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。