华北电网“428”事故分析

1999年4月28日发生在北京房山变电站的系统解列事故是华北电网历史上最为严重的事故之一。此次事故导致华北电网枢纽变电站——房山站220 kV母线全停,进而使华北电网解列为3个独立系统,并造成部分负荷停电。文中简要介绍了事故的经过及处理过程,指出电网结构薄弱、电气主接线可靠性不高是这次事故扩大的主要因素。     

房山500kV变电站计算机监控系统存在的问题

房山500 kV变电站是华北电网的500 kV枢纽变电站。本文从设计、工程实施、运行维护三方面,分析了该站计算机监控系统存在的主要问题,提出了改进意见及应吸取的教训,以使该计算机监控系统更好地发挥作用。     

电力建设大事录

2007年10月4日 华北电网有限公司重点工程项目——保北至房山Ⅱ回500kV输电线路投产运行。与此工程一同投运的还有房山、保北500kV变电站扩建出线间隔工程。该输电线路全长102．668km，线路跨越障碍物多达104次，工程建设历时346天，实现了工程安全、优质投产目标。     

美国洛杉矶"9·12"大面积停电事故过程

美国洛杉矶市的城市电网为230kV多回路环网（见图1、2），环网上有8个变电站（包括发电厂的升压站）。与外部系统联系的线路有：Rin-RS变电站的2条500kV线路、RS-E变电站的1条500kV线路和RS-B变电站的2条287kV线路，外部的电力来自这5条线路。事故发生前，洛杉矶电网只有1条外环线因为维护停止运行，系统的负荷大约是3733MW。本地（受事故影响的地区）的发电容量大约为1200MW，其中664MW的发电容量来自洛杉矶的南部，剩余的电力由外部送入。     

东北与华北联网后的频率调整

东北电网与华北电网将在2001年通过500kV姜家营变电站至绥中电厂之间的一回500kV绥姜线实现交流互联,这将是国内跨省区之间首次实现500kV交流互联。对于华北,东北这样一个大型互联系统,如何实现有功功率和频率的自动调节,使整个系统的发电功率和负荷功率维持平衡,系统频率维持相对恒定,且额定频率的偏离不超过允许范围,将是面临的新课题。文中论述了华北、东北两大岛TBC、各分区TBC控制方案。     

网源动态

电网华中、华北两大电网在河南亲密握手2006年6月28日,随着500kV安阳洹安变电站顺利投运,华中、华北两大电网在河南亲密握手。洹安变电站于2004年底开工建设,是三峡电力豫北输送配套工程的核心,由国家电网公司投资。洹安变电站的投人运行实现了河北邯郸、河南新乡两座500kV变电     

内蒙古电网枢纽变电站全停事故仿真分析及控制策略研究

随着内蒙古电网500kV输电通道的建成,结合欧洲"11·4"大停电事故,内蒙古调度通信中心使用DTS系统对500kV变电站可能出现的事故进行了仿真分析,发现500kV永圣域变电站在负荷高峰期如果发生500kV系统全停事故,将造成电网瓦解。经详细分析,发现电网500kV输电通道和重要220kV上的枢纽变电站发生全停事故,事故过程及后果具有相似性。结合内蒙古电网《2006年枢纽变电站全停事故处置预案》修订,认为加强事故发生时控制策略的研究,并采取积极有效的控制措施,可确保不发生因枢纽变电站全停造成电网瓦解或稳定破坏事故。     

区域电网DTS联网演习系统的研究及应用

基于区域电网联合反事故演习系统应满足的功能需求,设计并实现了区域电网调度员培训仿真(DTS)联网演习系统.以华北电网为例,介绍了区域电网DTS联网演习系统的设计方案、体系结构、硬件配置以及关键技术.该系统已多次在华北电网联合反事故演习中发挥重要作用.     

由"8·14"美加大停电看北京预防和应对大停电事故

"8*14"美加大停电事故所揭示出的电网运行中的问题,在华北电网也不同程度地存在.因此,"8*14"美加大停电的事故教训对华北电网的调度运行工作也有着重大的借鉴意义.由于北京作为首都的特殊地位,如何预防和应对大停电事故的问题尤显突出.为此着重就北京如何预防和应对大停电事故提出一些看法.     

华北电网广域实时动态监测系统

基于同步相量测量技术的电网实时动态监测系统能在线监测系统动态过程的全貌,同时,其记录的电网扰动事件数据有助于对仿真系统的模型与参数进行离线校核.文章结合华北电网实时动态监测系统的研制,论述了该系统的构成、主要功能和特点.该系统一期工程由华北网调主站系统和安装在7个关键发电厂和变电站的子站装置构成,子站与主站之间通过调度数据网连接.文章结合东北500kV系统三相短路大扰动试验介绍了该系统在华北电网中的实际应用情况.     

Comments on "Deficiencies in the way scattering parameters are Taught"

Equivalent representation of multiport circuits by the use of scattering parameters is of fundamental importance, especially in the microwave circuits area. However, in most cases, only a few pages of textbooks are devoted to this topic; based on the author's experience, the students find it somehow difficult to understand the physical meaning of scattering parameters (while they find other representations, like Z, Y, hybrid, or transmission parameters, easy to understand). For this reason, the contribution given by Sadiku (IEEE Trans. Educ., Vol. 46, no. 3, Aug. 2003, pp. 399-404) is very important. Furthermore, in Sadiku's paper, three nontrivial examples are reported, through which the students can gain understanding of this fundamental tool. In two of the three examples, some points are unclear; this correspondence analyzes this lack of clarity.     

Are "Engineering" Graduates Prepared to Meet Their Employers?

The most important aspect of an educational program is to evaluate its merits in meeting the needs and concerns of those who hire its product, the graduates. The world of work is discussed and analyzed from varied viewpoints; individual wants and needs, how this relates to the employer-employee relationship, the attributes that most employers are seeking, and the specifi'c concems of industry in the technical spectrum. There are two sides to the work world-an employee is concerned about what he has to gain by considering a choice of employment: remuneration rewards, relevant work, challenging work, respect as an individual, social satisfaction, and the opportunity for career advancement; the employer will be concerned about what's in it for them should they hire the employee: basic skills, cooperative attitude, ability to communicate, loyalty, integrity, motivation, initiative, performance, and appropriate appearance. The "engineering" curriculum to meet these employee-employer needs is discussed and the reader is thus queried, depending upon their own frame of reference, to decide whether or not "engineers" are prepared to meet their employers.     

Portrayals of engineers in "Science Times"

Engineering plays a crucial role in the creation of technologies and infrastructure that make vital contributions to the U.S. economy and security, to U.S. prestige in the international arena, and to individual well-being through the provision of jobs, services, and products. Despite this, a large proportion of the U.S. public undervalues the role played by engineers in a wide variety of technologically-based activities, holds engineering as a less prestigious occupation than science, and regards engineers as less socially responsible than scientists. In addition, declining levels of enrollment by Americans in engineering programs, together with under-representation of women and minorities in the profession, are also seen as causes for concern. The reasons for these low levels of public understanding about what engineers do are most likely complex. However, since Americans obtain much of their information about science and technology through the mass media, it seems likely that media coverage of engineering plays at least some role in the formation of public ideas about engineers and engineering.     

Introducing the family of "Sen" transformers: a set of power flow controlling transformers

Real and reactive power flow in an AC transmission line are independently controlled by connecting, to a transmission line, a series-compensating voltage, which is variable in magnitude and at variable angle with respect to the transmission line voltage as well as the prevailing line current. The traditional technology of transformer and tap changer is used to implement this novel technique. An additional voltage regulation capability can also be implemented. The speed of tap changer operation determines the response time of this power flow controller, which is quite adequate in most utility applications. The response time can be improved if suitable solid-state switches are available to replace the mechanical taps.     

"Designing synthetic topological matter with atoms and lights"

One of the most interesting directions in quantum simulations with ultracold atoms is the expansion of our capability to investigate exotic topological matter. ...     

The IMS 2009 "Bonus" Issue [From the Editor's Desk]

This special issue of IEEE Microwave Magazine represents a new initiative of the IEEE Microwave Theory and Techniques Society (MTT-S) focused on the International Microwave Symposium (IMS) to be held in Boston, Massachusetts, 7-12 June 2009 (IMS 2009). In the pages that follow, you can read about the specific aspects of IMS 2009 and also the technical features that focus on the topics covered in the IMS 2009 panel, focus, and rump sessions. Our intention for this issue is to cover details of the IMS 2009, the Society's biggest meeting and one of the most anticipated events of the year for many microwave engineers, while still providing thought-provoking articles on state-of-the-art topics that will appeal to our readers who won't be attending the symposium.     

An anthrax "smoke" detector

We report a method for automated monitoring of airborne endospores, which combines an aerosol capture technique with endospore detection based on terbium luminescence turn-on. We have demonstrated quantification of aerosolized bacterial spores with a response time of ~15 min, a sensitivity of 10⁴ spores/ml, and a dynamic range of 4 orders of magnitude using a bioaerosol sampler, a microwave, and a lifetime-gated fluorimeter. Ultimately, the most attractive feature we have demonstrated is the unattended monitoring of aerosolized bacterial spores for the duration of a workday (~8 hours)     

"Wire" versus "wireless" communication

Though the integration of all modes of electrical communication is a practical fait accompli under the progress and aegis of information theory, the fact remains that there is an undeniable and healthy competition between wire and wireless means in almost all communication fields. I would like to present some aspects of this technical feud together with some personal technical souvenirs at this occasion.     

UIC Student branch fans the "flames"

The University of Illinois at Chicago (UIC) adopted the nickname the Flames in reference to the Great Chicago Fire of 1871, so it's only fitting that the university's IEEE Student Branch (SB) possesses the ability to rebuild quickly. The SB was looking to boost its profile and by keeping its Web site and events simple and remaining steadfast in networking, participation has increased in less than a year. That's no small task for a school with over 25,000 students, most of whom are commuters. With 30 active SB members, UIC has reached out to those nomadic students by going back to basics.     

变流电路中电解电容的"硅解"研究

电解电容是现代电力电子系统中用量多,体积大,可靠性差,寿命短的最薄弱环节。提出用高频电流型有源滤波器取代电力电子变流器直流环的电解电容,实现电解电容的“硅解”。实验结果验证了“硅解”方案的可行性,并取得了良好效果。