特高压输电线路污闪和风偏风险实时评估与预警

特高压输电线路跨越距离长,易受不同气象条件的影响,实现特高压输电线路在不同气象条件下的电气可靠性实时评估与预警对保障电力系统稳定可靠运行具有重要意义。分析了输电线路污闪和风偏闪络的机理,将气象数据引入特高压输电线路电气可靠性实时评估与预警中,结合未来1~72h数值天气预报的结果,建立了基于气象参数的特高压输电线路污闪、风偏风险实时评估与预警模型,预测特高压输电线路在不同气象条件下的污闪和风偏闪络电压,进而得到特高压输电线路在不同气象条件下的污闪和风偏闪络的风险等级,实现评估与预警。     

一种输电线的动态载流量评估方法及应用

输电线路状态监测手段的不足导致其利用率长期受限于保守的静态载流量,如何对输电线路动态载流量进行有效评估是挖掘线路输电潜能、缓解输电瓶颈的重要途径。鉴于此,从气象因子角度出发,首先运用导线热平衡模型对线路动态载流量进行了计算分析,并提出基于双端电气和气象信息的输电线路动态载流量评估方法;其次,针对某地区220 kV双回线提升线路利用率的需求,从离线统计和现场系统实际监测2个方面进行分析论证。结果表明,基于双端电气和气象量采集的载流量监测系统可在局部电网中发挥实际作用。     

三峡地区导线覆冰与气象要素的关系

气象要素是确定在一定区域内能否形成导线覆冰、形成什么种类的导线覆冰和形成多大的导线覆冰的基本条件。根据三峡观冰站的观测资料．统计分析了每次覆冰过程的主要气象要素如温度、湿度和风向风速的均值“及(或者)变化范围，得出了在三峡地区覆冰期间不同种类覆球形成的气象条件，提出了有效覆冰时间，覆冰参数等气象要素变最及其组合参数的确定方法，采用相关分析和回归分析方法计算分析了它们对覆冰量的贡献，并建立了冰重与气象要素之间的定量美系。可供在覆冰区域内的架空线路设计确定覆冰性质、进行频率分析和估算设计覆冰荷载等进行参考。     

基于温度概率预测的地下电力电缆可靠性模型研究

地下电力电缆周围气象温度具有不确定性。通过考虑气象温度对地下电力电缆可靠运行的实时影响,借助广义极值分布(Generalized extreme value distribution,GEV)对气象温度进行概率分布拟合,在此基础上分析了地下电力电缆的温度场和热阻等效电路,提出了基于温度概率预测的地下电力电缆可靠性模型,从而有效预测地下电力电缆的导体温度。数值仿真计算与实际测量结果的比较验证了该预测模型的有效性和准确性,为地下电力电缆可靠运行和温度在线监测提供了重要的技术支撑。     

基于气象参数的输电线路电气可靠性实时评估与预警系统设计与研发

输电线路的运行状态与所处的气象环境密切相关,为进一步提升输电线路自然灾害风险的在线管控能力,研发了一套基于气象参数的输电线路电气可靠性实时评估与预警系统。依据传统的输电线路覆冰增长、动态积污、雷暴预测以及风偏角计算模型,从气象部门引入定制化的实况监测、数值预报等气象参数,采用WorldWind三维地理信息框架和Web Service接口服务技术,实现输电线路冰闪、污闪、雷击以及风偏闪络风险的评估与预警。该系统已针对部分线路线开展了试点应用,输出的评估与预警结果与实际运行情况基本吻合,对于实时掌握线路运行环境以及在灾害来临前采取紧急应对措施具有十分重要的意义。     

Estimation of the sensitivity of the electrical energy demand to variations in meteorological conditions: History of methods and development of new approaches at EDF

The development of electrical heating makes French consumption of electrical energy increasingly sensitive to climatic random variations, and this considerably complicates the a posteriori analysis of realizations, not only for itself, but also as a help in forecasting. The necessity of having homogenous realizations as far as meteorological conditions are concerned, has led, for many years, to diverse reseacch and development projects at Electricité de France. A comprehensive survey is given of EDF activities in this area until the end of 1981. The results obtained by various techniques (linear or nonlinear regression methods, ARIMA models with transfer function and adaptive filtering techniques) are described.     

Application of Dynamic Model to Flashover of Ice-covered Insulators

The purpose of this paper is to study the effect of insulator dimensions as well as applied water conductivity on flashover voltage under icing conditions, using a dynamic arc model. The electrical performance of several insulators with various diameters and dry arcing distances were evaluated using this model. Moreover, in order to assess the influence of meteorological variables, different applied water conductivities were considered for the laboratory experiments. The model was found to be in good agreement with the experimental results. The results obtained indicate that flashover prediction is possible under ac voltage, using the proposed model. This contribution is also intended to provide a fresh perspective by contributing an innovative approach to this domain of research.     

气象干旱到不同等级水文干旱的传播阈值——以沁河流域为例北大核心CSCD

系统量化气象干旱到不同等级水文干旱的传播阈值对水文干旱早期预警与精细化管理具有指导作用。本文以黄土高原沁河流域为例,采用标准化降水指数和标准化径流指数表征气象干旱、水文干旱,运用游程理论识别干旱事件,并对干旱事件进行合并、剔除及气象干旱与水文干旱事件的匹配,同时使用贝叶斯网络结合Copula函数构建模型求解气象干旱到不同等级水文干旱的传播阈值。结果表明:随着水文干旱等级的升高,气象干旱到水文干旱的传播阈值增大,在传播过程中气象干旱强度削弱;沁河流域引发中度、重度及极端水文干旱对应的气象干旱历时阈值分别为12.8月、21.8月、30.9月,烈度阈值分别为14.2、22.4、30.0;沁河流域耐旱能力强与流域气象及下垫面条件有关。     

The PCIC and electrical safety

The Petroleum and Chemical Industry Committee (PCIC) has evolved into a leadership role in the IAS and the IEEE for industrial electrical safety measures. PCIC has accelerated progress in standards, regulations, product designs, work practices, and perhaps, more importantly, how to eliminate electrical injuries. In developing this article, the authors conducted surveys, reviewed historical documents, and interviewed long-time PCIC members in an attempt to document the evolution and impact, the organization has had on electrical safety. One of the goal of this article is to provide comprehensive bibliography and appendices that may be useful in developing further improvements and contributions to electrical safety.     

铁氧体对自动气象站雷电过电压抑制

为了抑制雷电过电压经电线、网络通信线侵入自动气象站的UPS和主控微机,研究了采用铁氧体来抑制雷电高次谐波的技术。低压模拟试验和基于MATLAB之SimpowerSystems软件包的高压仿真分析表明将铁氧体磁环套在电源线或信号线上,等效于在接地、屏蔽、均压和分流等防雷措施中接入一个并联电阻和电感,适当地选择磁环的参数组合能够削弱雷电过电压的幅值和陡度、阻尼雷电波的传播。它与一些常用的防雷器材配合使用组成的综合防雷系统,网络结构简单可行且能对自动气象站进行有效保护。     

浅议SF6色谱分析

随着电力系统的无油化,SF_6作为一种良好的绝缘灭弧介质,其应用越来越广泛,本文主要讨论SF_6使用及检验中气相色谱的应用。     

Industrial power system analysis with database access

This paper presents a useful software tool to analyze an industrial power system. The program has two main functions. One is to let the personnel of the industrial plant graphically set up and access the electrical database, such as filtering or searching information. The database can be included in the company documentation. Based on the database, the other is to graphically perform a load-flow analysis and short-circuit current calculation on a PC. Considering the structure and connection of transformers, a system analysis is performed with appropriate phase shifts. In addition, the unbalanced fault current calculation is generalized with all types of faults happening in a power system such as single-phase fault or multiphase fault, with or without faulted impedance, and bus faults or cable faults. Using the results of load-flow analysis as the prefault condition instead of preset voltage, one can obtain more accurate and practical results. Therefore, this program is very useful for industrial companies to analyze their electrical power system and train their electrical personnel     

基于混沌时序-随机森林回归的堆石坝料加水量预测研究

堆石坝碾压施工过程中一般通过对坝料加水以提高压实质量。然而现阶段针对坝料加水量控制的研究中,存在无法精确给定加水量、未考虑坝料上坝后摊铺施工过程中气象因素对坝料含水率的影响等问题,难以保证坝料在碾压施工开始时满足坝料设计含水率的要求。为有效控制堆石坝坝料加水量,基于混沌时序和随机森林回归方法,建立考虑气象因素影响的堆石坝料含水率变化预测模型并精确给定加水量,主要包括：①利用混沌时序方法,在设定时间内进行气象信息短期预测;②建立基于随机森林回归方法的含水率变化预测模型,预测气象因素引起的坝料含水率非线性变化,并通过十折交叉验证检验了模型预测精度;③结合预测的含水率变化、坝料初始含水率、设计含水率和坝料质量对加水量进行精确计算。在碾压监控系统和运输监控系统的基础上,结合某实际工程,验证了该方法的有效性和准确性,并与现有加水方法进行了对比,为堆石坝坝料加水量的精细化控制提供了科学指导。     

山东省气温与最大负荷和用电量的关联性分析

以山东省近几年的负荷和用电量数据为基础,在利用统计方法和散点图分析了各种气象因素对电力负荷和用电量的影响后,得出了影响较大的因素为气温的结论.据此开发了用于分析气象因素与负荷和用电量的关联性的软件,该软件功能齐全,操作简单.文中得出的气温对负荷和用电量影响的特点及规律可以为供电部门和调度部门的工作人员提供有用的参考信息.     

微地形环境下输电线路微气象分析与预测技术

为了研究微地形区域输电线路运行的气象情况,在小气候理论基础上,以华北地区处于典型微地形区域的3条输电线路、且历史上发生过由极端天气引发的输电线路事故为例,分析了山区微地形导致的微气象形成机理,并利用多元回归分析方法建立了微地形气象因子与宏观大气参数之间的回归预测模型。研究结果表明,该方法可以从定量角度揭示微气象参数之间的关系,能够对微地形区域输电线路运行的微气象参数情况进行分析与预测,为建立输电线路电气可靠性实时评估与预警系统奠定基础。     

电力设备冷却技术及其强化传热研究进展

对电机、变压器等主要电力设备的冷却技术进行了综述，介绍了传热强化技术的最新研究进展及其在电力设备中的应用前景，从而为电力设备的热设计及优化提供了参考依据。     

交联聚乙烯电缆绝缘中的导电和非导电型电树枝

研究发现,交联聚乙烯中存在导电型、非导电型和混合型三种电树枝,分别对应于不同的生长机理,主要取决于介质的聚集态和施压频率等.实验表明,均匀结晶态中的电树枝为导电型,非均匀结晶态大球晶界面的电树枝为非导电型;频率会促进非导电型电树枝的发展,但对导电型电树枝的引发与生长不产生显著影响.非导电型电树枝引发过程较弱时,会缓慢发展成为混合型.研究分析证实,空间电荷限制下的树枝尖端微击穿是深入到晶体中的导电型电树枝缓慢发展的主要过程,局部高温高压气体沿晶界弱区迅速膨胀、树枝通道中的局部放电和电荷复合等是非导电型电树枝发展的主要过程.     

Ensemble Stimulation of Embryoid Bodies using Substrate-Embedded Electrodes

Precise control of differentiation processes of pluripotent stem cells is essential for regeneration medicine, and electrical stimulation is one of the promising techniques, particularly for the regulation of neuronal regeneration. In the present study, we developed substrates with embedded electrodes, which allowed ensemble electrical stimulation of embryoid bodies (EBs). Microcavity-array patterns were fabricated on substrates with embedded electrodes. Uniform-size EBs of P19 cells were prepared, inserted one by one in each microcavity, and electrical stimulation was applied through substrate electrodes. Stimulus-induced intracellular calcium transients were successfully monitored by fluorescence imaging. The results suggested that this method would be useful for applying precisely controlled electrical stimulation to a large number of EBs of stem cells. Copyright © 2009 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

一种新的输电线路阻塞责任定量分析方法

输电线路阻塞会影响电力系统运行的安全性和经济性,定量分析线路阻塞形成的原因将有利于提出更为合理的阻塞管理方法,保证电力市场的安全运行。提出一种新的基于电力网络源流路径电气剖分方法的输电线路阻塞分析方法。利用电气部分方法将阻塞线路上的电气信息量进行剖分,分析线路阻塞的具体成因,即阻塞到底是由哪些网络源（通常为发电机节点）和网络流（通常为负荷节点）通过何种电气路径形成的。在全面掌握阻塞成因的电气信息后,将网络源流各自应承担的电气责任在三种范围内进行了定量评估,获取分析对像应承担的阻塞责任。以IEEE14节点为例,说明所提方法的有效性。     

Smart electrical energy networks [review of Power Electronics in Smart Electrical Energy Networks (Strzelecki, R. and Benysek, G.; 2008)] [Book News]

The major aim of this book, a monograph written by an international team of authors, is to present the features, solutions, and applications of the power electronics arrangements likely to be useful in smart electrical energy networks. The book is organized into 12 chapters and includes the following topics: principles of electrical power control; an overview of power electronics converters and controls; quality problems in smart networks; high frequency AC power distribution platforms; integration of distributed generation with electrical power systems; active power quality controllers; and grid integration of wind energy systems, among other topics. The book includes numerous practical examples and very good illustrations that highlight the discussed topics. Each chapter begins with an introduction and is supplemented with a summary and list of references at the end. The book can be used a s a reference for advanced senior-level courses.