浅析输电线路鸟害故障与防治策略

剖析了重庆地区输电线路鸟害故障,简述了输电线路鸟害故障的类型、形成及其基本特性,并通过技术经济比较,提出了基本防治对策。     

常见电力电缆故障的判断和测试

介绍了电力电缆的诸多优点及其类型，针对电力电缆线路运行中产生的各类型故障，提出了电力电缆故障的判断方法及故障的测试方法。     

配电网自动化系统线路故障自动隔离功能探讨

本篇文章主要对配电网自动化系统的概念、作用及其构成作了相关介绍,并就其系统所具有的线路故障自动隔离功能展开详细探讨,并在最后对线路故障区段的查找的基本原理作了简要阐释,以供相关同志参考。     

高压直流输电线路雷击故障仿真与故障选极方案

高压直流输电线路极线间的电磁耦合,在雷击情况下特别明显。一极发生故障将同时在健全极线上感应出暂态电气量,有可能造成健全极线路保护误动,从而导致单极故障时双极停运,影响送端电网和受端电网的安全稳定运行。本文在对雷击暂态仿真方法进行研究分析的基础上,以±660kV高压直流输电线路为例,利用PSCAD暂态仿真软件建立了雷击暂态仿真模型,分析了雷电流幅值对直流输电线路绝缘的影响。为避免雷击故障后非故障极的线路保护误动,提出了基于电压突变量积分值及其比值的单端故障选极判据。     

浅谈电力线路故障及检测

电力线路的运行安全是电网公司保障供电稳定的重要目标。电力线路故障威胁着电力线路的运行安全。本文分析了接地故障、短路故障和超负荷故障产生的一般原因,并根据三种线路故障的特点总结了电力线路故障检测的指标,为设计电力线路故障检测系统提供了重要依据。     

基于故障录波的高压配电网混合线路阻抗测距实用化研究

通过结合故障录波数据和高压配电线路架空、电缆分布参数及其阻抗参数,并对阻抗法加以改进从而实现实用化。利用基于小波变换及突变量法相结合提取故障特征时刻并选出故障线路,获取故障电压和电流数据,进而针对不同故障情况对微机故障测距原理进行变换定位故障点位置。经验证表明,该方法能够较为精确地定位故障区域,极大地改善目前输电线路故障点查找定位的现状,并且精度满足现场运行检修要求,有较强的实用性。     

基于绝缘子内置电容分压的配电线路故障检测技术研究

短路故障和断线故障是配电网常见的线路故障，对配电网安全稳定运行有重要影响。本研究以不接地配电系统为对象，提出在线路绝缘子内部集成陶瓷电容，通过电容分压检测配电网线路故障的暂态电压信号，进而实现配电线路故障检测的新方法。采用PSCAD/EMTDC软件建立了短路故障和断线故障情况下配电系统的仿真模型，研究了典型故障工况下绝缘子内置电容分压器监测的线路电压特征。结果表明：对于低阻和中阻接地故障，线路故障相电压迅速减小至稳定值，健全线路对应相的电压欠阻尼振荡衰减至稳定值，故障线路与健全线路的暂态高频信号特征明显；对于相间短路故障和单相断线(含接地)故障，可根据负荷侧稳态电压特征进行检测与识别。这表明本研究提出的绝缘子内置电容分压的配电网线路故障检测方法是可行的。     

高级装饰中电气火灾的防治

一、国短路故障引发的火灾短路是指相线之间、相零之间直接金属性的电气连接。短路电流通常为数百安，甚至上千安培，在短路点形成电弧，引燃附近可燃物。当短路保护电器设计选用或整定不当或使用了假冒产品，短路保护电器拒绝动作，不能及时切断故障线路，短路电流将使导体产生高温，使线路绝缘气化燃烧或将导统金属熔化，熔珠掉落在可燃装修材料上而引发火灾。短路故障的防护：1．短路保护电器的选择：线路的短路保护电器应在短路电流使导线及其连接件产生的热效应造成危害之前切断故障线路。2．必须杜绝伪劣产品。二、因接地故障而5！发…     

雷电定位系统在输电线路雷击故障分析中的应用

雷击故障是输电线路的主要故障,识别雷击故障原因能有效提高和改进输电线路的雷击可靠性水平。结合220kV输电线路雷击故障的现场调查数据,采用雷电定位系统得到的雷电流参数在电磁暂态仿真软件ATP-EMTP建立输电线路雷击过电压仿真模型,分析了输电线路在不同雷电流下的跳闸性质。仿真结果表明,基于雷电定位系统和电磁暂态仿真能有效判别线路故障的性质,为线路的运行、维护和改造提供参考。     

试论10kV辐射式线路接地故障查找方法

应用可靠性理论,通过对10kV线路永久性接地故障查找的分析,提出了一种查找10kV线路永久性接地故障的方法,能有效提高10kV线路故障时的供电可靠性,减少故障查找时间,提高故障查找效率。     

建筑装饰之我见——建筑外形式的装饰艺术

建筑是一部人类文明史,建筑装饰艺术是其中最精美的语言,它记载着科学技术的发展和文化艺术的进步,它描绘出风土人情与时代风尚。本文主要论述了建筑外形式装饰艺术的涵义及设计要点,对建筑装饰艺术的形态构成、造型与装饰、装饰的视觉效应以及建筑外形式装饰艺术的个性和设计中应注意处理好的关系进行了讨论。     

Environmental Management of Landfill Sites

The paper reviews various options adopted in the UK for engineered protection measures aimed at preventing pollution to the environs of landfill sites. The advantages and limitations of both natural and synthetic lining materials are discussed, recognizing the constraints posed by the geometry and geology of prospective landfill sites. Particular attention is given to the Environmental Safety Centre experience with techniques designed to minimize both leachate and gaseous emissions, and hence prevent pollution of ground and surface waters, and reduce hazards to nearby property. Options for operational practices and restoration procedures are discussed in relation to the control of degradation processes and polluting potential. Included in these options are design and operation of leachate and gas collection/treatment systems, phasing of landfilling operations, and progressive restoration of sites. Monitoring requirements are emphasized as a vital measure of the success or failure of site designs and operational practices in ensuring that appropriate environmental protection is achieved and maintained.     

景框的中介——电影与建筑中的动态布局

本文探讨了作为电影和建筑中的一个主要空间构成主题——景框理念。对空间的电影几何关系和建构几何关系的设置.体块、空间、视角、景观、相机和演员的相对位置和组织等.会产生特殊的张力、关系和动态——所有这一切都指向景框所带来的触媒作用和示能作用。电影与建筑中的空间是许多潜在的力量和相互作用的动力场,它涉及对空间景框、机制和策略的部署与调控,由此实现构成的、语义的和叙事的目的。景框建立了边界,但也促进并提醒可能会遇到的那些模棱两可、针锋相对与制约的突破.以及一种呈现怪诞特征的潜力。     

玻璃钢锚杆托盘及螺母极限应力和位移分析

为了研究支护用锚杆在极限应力作用下力学特性,建立了锚杆托盘及螺母的有限元模型,采用ANSYS程序对螺母及托盘的应力、位移进行了数值仿真分析。研究了托盘及螺母在极限应力下的接触特征;绘制了托盘及螺母的应力云图,得到了托盘及螺母内部的应力、位移分布情况。结果表明,托盘边缘及托盘内部大小圆盘连接位置较为危险;螺母中间位置由于受托盘的挤压容易发生破坏;加肋可以提高锚杆的极限承载力,为结构的优化提供借鉴。     

Designing Whole Landscapes

A whole-landscape approach is critical to ensuring conservation and enhancement of biodiversity in farmed landscapes. Although existing agri-environmental schemes are constrained by property boundaries and voluntary take up, the potential for adopting a whole-landscape approach to planned countryside management is currently favoured by a number of factors. These include economic uncertainty in some agricultural sectors; the introduction of a reformulated rural development policy; increased understanding of relationships between biodiversity and management; and the introduction of Geographical Information Systems (GIS) technology that allows future landscapes to be visualized by stakeholders. Ecological and socio-economic aspects of whole-landscape planning in a study covering 31 neighbouring farms in west Oxfordshire are reported. A baseline was first compiled that included information on: property boundaries; land cover; relationships between hedge and field margin management and key taxa; and farmer socio-economics and attitudes towards agri-environmental measures, conservation and sustainable agriculture. Future scenarios of integrated wholelandscape management were then developed, designed to deliver amenity, environmental and biodiversity benefits. These scenarios were presented and interpreted to farmers and conservation and amenity stakeholders with the aid of GIS-based maps and three-dimensional virtual reality visualizations. Farmers' responses are reported and the potential for implementing whole-landscape planning is discussed .     

增加，改造，修正：不断成长的博物馆

在２０世纪末期．欧美的博物得变成了一种“加法动物”不断进行着改建、扩建和加建．从而涌现出大量风格方式不间的建筑实例其中既有失败．也有成功。本文选择了部分典型案例如以分析，特别肯定了托马斯·毕比和西萨·佩里的设计概念和方法，并提出了未来的改．扩建将面向未来不断发展的观点。     

Magnetoelastische Spannkraftmessung in Bauwerken

Magnetoelastic Measurement of Prestressing Force in Civil Structures The knowledge of the tensile force of prestressing steel elements and its reliable and non‐destructive determination are of essential importance for the assessment of the structural health condition of prestressed concrete structures and tie‐back systems in terms of structural safety, serviceability and durability. For the evaluation of the prestressing force in steel tension members, the measurement technique presented in this contribution is using the magneto‐elastic effect (ME‐effect) of ferromagnetic materials. This effect describes the reverse‐proportional correlation between the mechanical stress and the magnetic properties of ferromagnetic materials. The cylindrical coiled sensors pushed over the tendon and the measuring device developed and practically optimized at the iBMB/MPA of the TU Braunschweig enable a fast and reliable measurement of the prestressing steel force after an initial calibration. In this contribution first the state of the art of prestress measurement techniques for steel tension members is presented. Afterwards, the ME‐measuring method with the basics and merits of magneto‐elastic prestressing force identification is shown. Further recent research results as well as several building applications will be discussed.     

The town and village greens of England and Wales

This paper considers the nature and significance of town and village greens within the landscape of England and Wales. It reflects on problems of definition and on the limited availability of data concerning the origins and geographical distribution of greens. The paper draws attention to the registration of greens following the Commons Registration Act 1965, and summarizes information collated from the registers subsequently prepared by local authorities. Details of numbers of greens and their spatial density at county level are presented, and reference is also made to rights of common on greens, and to the ownership of the greens themselves.     

Pollution due to coir retting and its effect on estuarine flora and fauna

One of the striking features of Kerala state is the continuous chain of lagoons or backwaters existing along the coastal region. The backwaters support rich and diverse life forms and provide crucial nurseries for shrimps and fishes as well as habitat for oysters, clams and mussels which later enrich the ocean and make Kerala the principal exporter of marine products amongst the states of India. The shallow fringes of the backwaters and the channels drawn from them are used for retting of coconut husk. It adversely affects the productivity of the backwaters and is harmful to marine fisheries. The retting of coconut husks in backwaters is brought about by the pectinolytic activity of micro organisms especially bacteria fungi and yeasts degrading the fibre binding materials of the husk and liberating large quantities of organic matter and chemicals into the environment, including pectin, pentosan, tannins, polyphenols, etc. Consequently hydrogen sulphide, phosphate and nitrate contents increase while dissolved oxygen and community diversity of plankton decrease in the ambient waters during the retting process. The present study is to evaluate pollution due to coir retting activity and its influence on quality of water and estuarine flora and fauna.     

堆土加卸载与基坑开挖叠加对既有隧道变形的影响研究

针对堆土加卸载与基坑开挖叠加效应导致既有地铁隧道变形较大的问题,建立考虑加卸载叠加效应影响的三维空间分析模型,研究不同堆土加卸载叠加基坑开挖卸载模式对邻近地铁隧道变形规律的影响,探讨隧道在堆土加载、移土卸载再叠加基坑开挖下的变形规律。结果表明:正上方堆土加卸载对隧道的竖向位移影响较大,是侧向堆土加卸载的3倍～5倍; 在经历堆土加卸载后,隧道会残留不可忽视的变形,其残留竖向位移约为加载后位移的62%; 堆土加卸载叠加侧方基坑开挖时,隧道变形受基坑开挖深度的影响较大,大于隧道埋深的开挖阶段会加剧隧道变形; 4种叠加模式中,正上方堆土加卸载-侧方基坑开挖卸载隧道最终竖向位移最大,约17 mm,侧方堆土加卸载-异侧基坑开挖卸载隧道最终水平位移最大,约8 mm,邻近隧道施工时应充分考虑叠加效应的影响,尽量避免这两种情况。