Passive microwave receive filter networks using low-Q resonators

In this article, it has been shown that under certain circumstances, i.e., in a receiver, it is possible to allow microwave filters to have significant passband insertion loss. Systems analysis of various receiver configurations shows that acceptable noise figures and intercept points may be obtained in receivers containing lossy filters, i.e., ones with low-Q resonators. Thus, the engineering problem is how to develop design techniques for filters that have low-Q resonators, but with acceptable response in terms of selectivity and pass-band flatness. A review of several techniques for bandpass and bandstop filters is presented.     

Stochastic Optimal-Control Approach to Automatic Incident-Responsive Coordinated Ramp Control

This paper presents a stochastic optimal-control-based approach to real-time incident-responsive coordinated ramp control. The proposed coordinated ramp-control methodology includes two major functions, i.e., 1) identification of control-zone-based congestion patterns using the modified generalized-sequential-probability-ratio-testing technology and 2) group-based ramp control using stochastic optimal control coupled with extended Kalman filtering technologies. With the aid of the Paramics microscopic traffic simulator, numerical studies under various simulated incident-induced congestion conditions were conducted. Corresponding numerical results indicate the feasibility of the proposed ramp-control method in responding to diverse lane-blocking incident-induced traffic-congestion conditions     

发电厂空冷技术的现状与进展

介绍了3种空气冷却系统:即直接空冷系统(GEA)、表面式凝汽器的间接空冷系统、混合式凝汽器的间接空冷系统(海勒系统)的发展现状。指出国内直接空冷电站发展空前迅速,但是否过热值得注意。文章概括性的介绍了空冷系统的关键技术,如冷却元件、翅片管束结构、风机、设计技术的最新发展情况,以及干式—湿式联合冷却塔的设计原理。对于热风再循环和横向风对冷却效果的影响给出了温度分布模拟图。文章还介绍了一种新的空冷散热器组装方案:即采用模块组装,可缩短工期,降低投资。     

A computer-aided facility for testing gas-turbine power stations

Structural and parameteric synthesis of an automatic control system for gas-turbine power stations complicated by the complexity, nonlinearity, and multimodality of the control object, which is both the gas-turbine power station itself and the associated electric-power system, is conducted using the simplest possible mathematical models. The development of simulation models of the electric-power systems of various structures and element compositions and analysis of the functioning of the latter when reproducing a given list of external and internal disturbances are a topical task. The conditions of a test stand offer the possibility of combining the stages of computer-aided tests, i.e., simulation of the automatic control system, and semirealistic tests, i.e., tests of mockups and experimental and pilot prototypes, using a computer model of the electric-power system. The development of program modules for simulation of the electric-power system is considered. The modules are integrated into a subsystem for testing power-generating plants. The use of the Java language facilitates the cross-platform properties and universality. The computation of the dynamic modes is represented as a sequential computation of the static modes in every sampling step. Models of the elements of the electric-power system have been developed.     

Scattering Parameters-Based Channel Characterization and Modeling for Underground Medium-Voltage Power-Line Communications

Power-line communications (PLC) technologies rely on the power grid for data transmission. Since the communications channel is already deployed, this communication alternative is specially interesting for the power grid owner (i.e., the electrical utility). The medium-voltage (MV) distribution network, located after the last step-down electrical substation with typical levels from 6 to 25 kV, directly feeds large consumers and small ones through several transform stations. The growing interest on MV-PLC technology, the natural aggregation point for data coming and going into the low-voltage (LV) network, faces the same issue that the LV–PLC technology did (and does): standardization. In this way, a properly implemented channel model will allow the design of suitable modulation and access methods. This paper proposes a deterministic channel model for the MV underground network transfer function, based on a complete set of measurements performed in an MV urban ring. Moreover, the characterization of the MV–PLC channel elements as well as the noise scenario and access impedance have been carried out.      

Evaluating Dielectric Impedance Spectra using Effective Media Theories

The immittance spectra (i.e., impedance and modulus representations) are calculated for various effective medium theories, i.e., the Maxwell-Wagner (MW), Hashin-Shtrikman (HS), Bruggeman Asymmetric (BA) and Bruggeman Symmetric (BS) models, with emphasis on their individual microstructures. In addition the brick-layer (BL) model is also considered. The BL and MW-HS models yield similar single impedance arcs for a relatively low volume fraction conductive matrix (coating on the low conductivity phase). The BA model yields single impedance arcs different from the MW-HS models. The BL and MW-HS models yield virtually identical dual impedance arc behavior for a low volume fraction insulating matrix (coating on the high conductivity phase). At low volume fractions of insulating matrix, the low frequency arc due to the insulating material for the BA model is much smaller than for the MW-HS model. The BS model exhibits single impedance arc behavior when the volume fraction of conductor is above or near the percolation threshold and dual arc behavior somewhat below the percolation threshold. Equivalent circuits for these model materials are discussed, and application is made to experimental data for various electroceramic systems.     

Trends of permanent‐magnet synchronous machine drives

This paper presents recent trends of permanent‐magnet synchronous motor (PMSM) drive technologies in Japan. Since the PMSM drives have many advantages over other drives, e.g. high efficiency, high power density, etc., many of the motor applications have been changing their power sources to the PMSMs. Particularly, interior permanent‐magnet synchronous motors (IPMSM) are epoch‐making and are intensively studied among researchers, scientists and engineers. According to the survey of the recent innovative technical trends, the PMSM drive technologies have been making a remarkable advancement in the fields of analysis‐and‐design techniques, various sensorless‐control techniques, power converter control techniques, and application specific drive systems. Copyright © 2007 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

35 kV及以下XLPE电力电缆试验方法的研究

通过对交链聚乙烯（ＸＬＰＥ）电力电缆试品的工频、０．１Ｈｚ超低频和振荡３种击穿电压的平行比对试验研究,探讨能够有效发现、判别ＸＬＰＥ电力电缆运行故障隐患的试验方法,试验研究结果表明：振荡波电压试验能够有效地发现电力电缆及其附件的制造和安装质量缺陷,超低频电压试验能够有效地发现电力电缆及其附件绝缘树枝状早期劣化缺陷;工频电压试验是一种较好的方法,需进一步深入研究。     

低低温电除尘器绝缘装置设计与分析

低低温电除尘技术烟气温度低,高压绝缘瓷套须采取防结露积灰措施以保证低低温电除尘器的高运行稳定性。设计了3种适合低低温电除尘技术的高压绝缘装置,包括绝缘子小室结构、宽大梁内结构、大保温箱结构,分析了各自的结构优势和特点,并将该技术在温州电厂和淮阴电厂低低温电除尘器中的应用作了重点阐述,该装置的应用成功解决了低低温电除尘项目的高压绝缘易失效的问题。     

Continuing Engineer Education in the Hitachi Group

This paper describes the basic concepts, purposes, curricula, educational methodology and evaluation procedures of the new continuing education for engineers being conducted within the Hitachi Group. This Continuing Engineer Education comprises three courses, i.e., design engineer training, production engineer training and quality assurance engineer training, for experienced personnel. Each of these courses involves a four week sojourn at a lodge for intensive education as the core of the program. These curricula place emphasis on lectures by corporate executives as well as on dialogues with them. They also include case studies at plants and laboratories in addition to class work on the technologies of various special fields.     

AsTeRICS,a flexible AT construction set

A vast number of people with disabilities are supported by assistive technologies (AT). Often, AT solutions do not directly fit the specific requirements of a user, making costly adaptations necessary. Assistive Technology Rapid Integration & Construction Set (AsTeRICS) aims to change this situation by employing rapid prototyping technologies in AT. A construction set of building blocks to create flexible prototypes for each individual user is provided. This set is configured by a visual modelling software application which allows to connect all building blocks as needed, tailoring the prototype to the user's abilities and needs. Building blocks include sensors (which in this context includes not only stand‐alone sensors such as simple switch inputs but also vision systems, brain computer interfaces, and many more), data processing elements (mathematical and flow control), and actuators (such as mouse/keyboard replacement, smart environments, and mobile phone access). As central part of AsTeRICS, a runtime environment has been developed, handling all signal processing and data exchange operations needed for the interaction of the building blocks. Copyright © 2014 John Wiley & Sons, Ltd.     

StoryGrid [educational computing]

The StoryGrid project undertook studying the role new interface technologies might play in education, particularly at the high school level. Unfortunately, technology often seizes center stage in high school classrooms; i.e., it becomes the topic of instruction. We believe that learning about technology would be most successful when technology is not the topic, but simply a tool used during instruction. StoryGrid, therefore, was designed to support and to enhance existing narrative activity in classrooms by adhering to the following goals: trigger reflection and interpretation, accommodate individual expression and encourage student discourse.     

超低排放燃煤电厂和燃气电厂综合对比

燃煤和燃气发电是中国火力发电的两大主流形式。从发电与控制污染技术、环境效应和经济效益3方面对超低排放燃煤电厂和燃气电厂进行了综合对比,对比结果表明：（1）从发电和污染控制技术看,超低排放燃煤电厂已完全自主研发生产,整体技术已跨入国际先进水平;燃气电厂仍采取进口的方式,需加快掌握燃气轮机制造的关键技术;（2）从环境效应看,超低排放燃煤电厂在气、液、固等常规污染物排放上均达到有效控制,对环境影响已较小,当燃煤发电标准煤耗不大于全国平均水平时比燃气电厂更清洁;（3）从经济效益看,超低排放燃煤电厂继续保持相对于燃气电厂较大的发电经济优势。研究结果可为客观看待两类电厂的优劣提供理论参考,并为国家制定相关政策提供依据。     

双向智能电能表功能需求和结构性能分析

研究了多功能电能表相关标准和智能电能表功能规范（Q／GDW354—2009）,结合智能电网用电环节发展的需求,针对数量巨大的单相智能电能表,提出几点新的功能需求;根据制作和调试智能电能表样机过程中的体会,对智能电能表主要组成部分和关键元器件进行了性能分析,总结了各组成部分设计与应用中需要注意的问题;最后结合最新技术的发...     

Electronic system reliability: collating prediction models

This paper summarizes research done in the area of electronic system reliability and assesses the approaches used in the calculation of electronic system failure rates. A detailed literature survey is conducted to investigate the various available reliability prediction models. The paper starts with a definition of reliability, briefly discusses various regions of system failure rate in time, justifies the role of reliability prediction methods, provides a historical overview, classifies the traditional models into easy to understand categories and discusses the advantages and disadvantage, reviews the key models that are currently in use, and compares the first and most widely used model (i.e., MIL-HDBK-217) with the most recently introduced model (i.e., PRISM).     

DataLab-J: a signal and image processing laboratory for teachingand research

DataLab-J is a software signal and image processing laboratory which has proved effective both as an educational "workbench" and in practical operational use. It requires a pedagogical tool, a research environment, and a fully operational data analysis system, i.e., it is used not only in undergraduate engineering courses, but in graduate study and general research. The system must be easily extendable, e.g., to allow undergraduates to perform practical programming of standard digital filters and image processing algorithms, or to provide a realistic platform upon which novel algorithms can be implemented. On a further dimension, the system must handle seamlessly and efficiently three broad data types: digital signals (sequences), images (possibly multiband), and multivariate data sets. The system is implemented in the programming language Java. DataLab-J has been operational for four years, has been used in an undergraduate image processing course, and as a platform for a great many dissertation projects. In addition it is in everyday use within a university signal and image processing research group     

Design aspects of industrial distribution systems to limit arc flash hazard

Industrial distribution systems have been designed in the USA, considering prevalent standards, i.e., American National Standards Institute (ANSI), IEEE, National Electrical Code (NEC), Occupational Safety and Health Administration (OSHA), etc., and arc flash was not a consideration for designing electrical power systems in the industry. Functionality and economics were the important factors, and will always be so. However, the arc flash analysis and limiting the incident energy will usher a new parameter in system design. It can be demonstrated that in many current installations and new installations designed without considerations of limiting the arc flash energy, the hazard risk category exceeds the highest Class 4 personal protective equipment (PPE), i.e., an arc thermal performance exposure value (ATPV) of 40 cal/cm/sup 2/. This paper discusses typical industrial distribution systems at low-voltage and medium-voltage levels and demonstrates the impact of system design decisions and protection on the incident energy and arc flash hazard reduction.     

A Step-Up Phenomenon of the Thyristor Control Circuit with Series RLC Elements

A circuit controlled by thyristors and having series RLC elements gives rise to a step-up phenomenon. The term step-up is defined with respect to the capacitance voltage on steady state operation, i.e., the ratio of the maximum peak value when controlled by thyristers to the peak amplitude when thyristors are short-circuited exceeds unity. The domain of possible step-up voltage is determined by the angle of displacement between current and voltage and damping factor. The step-up voltages appear across each element, i.e., not only across the capacitance, inductance, and resistance but also across the thyristors. The control characteristic has a distinctive hump phenomenon. The interrupted current results in waveform distortion, phase lag, and improved power factor. The difference of characteristics between the peak and rms values of voltages, particularly of inductance and thyristors, is large. The response time, which is evaluated by numbers of half cycles, is large when the step-up ratio becomes large. The output voltage when the circuit is used as a voltage source has a drooping characteristic.     

特高压线路施工新技术的应用

1000 kV晋东南—南阳—荆门特高压交流试验示范工程是我国首个特高压输电工程。针对特高压施工中基础混凝土方量大,铁塔高、大、重,采用8分裂导线等特点及难点,文章对特高压线路施工中的新技术、新工艺的进行了总结,包括：采用商品混凝土进行基础混凝土施工、采用900 mm× 900 mm×40 m钢抱杆以内悬浮外拉线的方法组立铁塔、采用自平衡塔式起重机组立耐张塔、采用飞艇展放导引绳等,可为今后的特高压建设提供参考。     

Transmission equipment reliability data from Canadian ElectricalAssociation

Frequent forced outages of power transmission equipment can significantly affect the performance of industrial and commercial power systems and the processes they control. Historical transmission reliability data provides the ability to predict the performance of various transmission line configurations and assess the economic impact of forced outages on industrial and commercial power systems. The prediction methodologies are presented in IEEE Std, 493 (i.e., IEEE Gold Book). This paper presents a summary of the Canadian Electrical Association's Equipment Reliability Information System statistics on the forced outage performance characteristics of power transmission equipment (i.e., transformers, circuit breakers, cables, etc.) for Canadian utilities for the period 1988-1992. The paper reveals the structure of the database and presents relevant summary data (i.e., the frequency and duration of forced outages) necessary for the application of these reliability methodologies. A knowledge of the primary causes of the major equipment forced outages as to whether the outages are primarily due to the subcomponents of the major equipment or to its terminal equipment is essential for designing, operating and maintaining a reliable transmission system. This paper discusses and identifies for each major equipment the primary subcomponent (e.g., transformer windings) and the terminal equipment (e.g., auxiliary equipment) which dominated the forced outage statistics of the major equipment for the five year period