Hybrid fuel cells technologies for electrical microgrids

Hybrid systems are characterized by containing two or more electrical generation technologies, in order to optimize the global efficiency of the processes involved. These systems can present different operating modes. Besides, they take into account aspects that not only concern the electrical and thermal efficiencies, but also the reduction of pollutant emissions. There is a wide range of possible configurations to form hybrid systems, including hydrogen, renewable energies, gas cycles, vapour cycles or both. Nowadays, these technologies are mainly used for energy production in electrical microgrids. Some examples of these technologies are: hybridization processes of fuel cells with wind turbines and photovoltaic plants, cogeneration and trigeneration processes that can be configured with fuel cell technologies, etc. This paper reviews and analyses the main characteristics of electrical microgrids and the systems based on fuel cells for polygeneration and hybridization processes.     

Epoxy chemistry for electrical insulation

This paper will examine some of the changes that have occurred in epoxy resins and their chemistry and will explore the effect of these changes on electrical insulation. The intent is to present the chemistry in a fashion that will aid insulation designers in compiling their systems and manufacturing processes and will provide enough understanding that some direction can suggest itself to those charged with making electrical products     

Main trends in the development of electric machines and the electromechanical systems on their basis

Modern trends in the development of electric machines and the electrical systems developed on their basis have been represented. It is shown how the worldwide processes (price increases for the generation of energy, depletion of the world’s reserve of liquid hydrocarbons, limitations caused by global worming) cause trends in the activities of scientists and electrical engineers, as well as electric machine engineering and power electronics as a whole.     

Error of measurement under technical diagnostics of energetic power plants

The processes of gaining and transmitting information that permit one to conduct technical diagnostics of electrical networks and power-supply systems (ENPSS) are investigated. Recommendations of how to decrease the errors in the systems of measurement, transformation, recoding, and information transmitting during technical diagnostics are given.     

Development of automated systems of scientific research for control and testing of electrical machinery

Theoretical and practical aspects of conducting research and integrated tests of electric motors by building models of objects and processes are considered. The structure of an automated system for control and testing of electrical machinery is described. The paper also presents the results of introduction of research-automation systems.     

A stitch in time...continuous supervision versus preventative maintenance-a new concept for petrochemical plants

Continuous supervision is a concept of preventative maintenance (PM) practices used in the German chemical industry. It has been accepted inclusion into the IEC 60079-17 standard. It is a process where periodic checks are mandated on explosion protected equipment by skilled personnel. The level of scrutiny of these checks are determined by an "executive technician" or engineering manager. The engineering manager must determine the frequency, duration, and severity of the checks based on his/her knowledge of the hazardous area environment, process area, and explosive protected equipment installed and advise the plant personnel to carry out those checks. With maintenance budgets shrinking, one way of providing continuous supervision or PM practices is by utilizing electrical monitoring and control systems (EMCs). EMCSs allow operators and technicians to monitor and diagnose the electrical systems controlling the petrochemical processes. These systems are complementary to the existing distributed control systems (DCS) that operate and monitor the petrochemical process.     

蓄电池电驱动系统的匹配和优化

电驱动系统是电动自行车的关键，而蓄电池是电驱动系统的关键部件。指出，电驱动系统各部件之间的匹配和优化对于提高电动自行车的质量有着重要作用和意义。着重介绍了蓄电池和充电器之间的匹配和优化以及蓄电池放电深度与循环寿命之间的关系。     

Adaptation of a traction DC power system for high-speed traffic

Ways to develop and improve traction power-supply systems and adapt them for high-speed highways are considered. One way to improve a traction power-supply system and make it more efficient is to increase the nominal voltage in the dc traction network up to 24 kV. This allows one to increase the throughput and carrying capacities of railways, increase the distance between substations, reduce the cross section of traction-network wires, and significantly reduce power losses in power-supply facilities. All this, alongside the absence of unbalanced supply voltage and inductive losses, as well as a significantly lower electromagnetic action on the infrastructure under dc conditions, results in a greater efficiency than in the case of any alternating- current traction power systems of alternating current. A mathematical model of dynamic electromagnetic processes in electrical circuits with semiconductor converters is fleshed out. Analysis and synthesis of electromagnetic processes and the main characteristics of multipulse converters, as well as a comprehensive technical and economic comparison, shows that 24-pulse rectifying circuits with a serial connection of threephase bridge are most efficient for these systems. These rectifiers provide an improvement in the quality of electrical energy not only for the primary power-supply system, but also for the traction network. They allow one to use simpler and more economical active-passive smoothing filters that provide the electromagnetic compatibility (EMC) of a new traction dc power system with the communication and railway automation facilities. In addition, the use of 24-pulse rectifiers can allow one to significantly reduce the consumption of reactive energy, reduce power losses in a traction network, and increase the efficiency of traction substations.     

A pedagogically effective structured introduction to electrical energy systems with coupled laboratory experiences

Electrical energy conversion systems and power supply systems form an integral component of electrical and electronic systems used in residential, commercial, aerospace, transportation, and manufacturing applications. Practicing electrical engineers are often called to solve electrical energy and power-related problems. Therefore, an effective course that provides graduating electrical engineers with an energy-oriented perspective is highly desirable in today's workplace. This paper documents a course that provides students with problem solving experience in electrical systems and electronic circuits. The paper presents the pedagogical premise, course objectives, and details of lesson and lab activities, student projects, and experiences.     

Interprofessional projects in advanced automotive power systems: an integrated education and research multidisciplinary approach

Increasing use of electrical power to drive automobile subsystems, which historically have been driven by a combination of mechanical and hydraulic power transfer systems, is seen as a dominant trend in advanced automotive power systems. This trend manifests itself through the more-electric-cars (MEC) concept, which requires highly reliable, fault-tolerant, and cost-effective electrical systems. This paper introduces the Illinois Institute of Technology (IIT) Interprofessional Projects (IPRO) Program and a series of multidisciplinary student team projects focused on applications of electrical systems in advanced automobiles. IIT's interprofessional course engages multidisciplinary teams of students in semester-long projects. It delivers a team-oriented project-based requirement within the undergraduate curriculum. Among its many benefits, the interprofessional course offers the opportunity to integrate the education and research environment of the university and, in this case, introduces students to the role of electrical systems in emerging automotive platforms that offer numerous research and technology application opportunities for electrical engineers.     

基于LABVIEW和STEP7的典型惯性模拟负载控制系统的设计和实现

基于LABVIEW和STEP7软件,设计并实现了用于模拟飞机典型惯性模拟负载控制系统。该统具有优异的电功率输出和调节能力,良好的人机交互功能和保护功能,能较好的满足民用飞机电气系统的试验需求。基于LABVIEW和STEP7的直流调速系统的成功实现,不仅保障了民用飞机电气系统设计验证工作,而且还积累了民用飞机电气系统试验配套设施研制经验,对民用飞机电气系统试验具有重要的指导意义。     

Basic electrical processes in dielectric liquids

The basic processes of electrical conduction in dielectric liquids are reviewed, attention being drawn to the similarities between conductive electrolytes and insulating liquids. The concepts of the electronic amorphous solid state are employed to provide a framework for the review. The conditions at metal electrodes can be incorporated naturally into the scheme, and it is known that the space charge layers occurring on them can control conduction. Although electrical breakdown itself is not considered, the underlying electronic processes which will develop when breakdown electrical fields exist in the liquid are considered     

Application of Fusible Overcurrent Protection for Electrical Distribution Systems in Glass Plants

Most glass plants in operation today have been in existence for many years. In some cases maintenance of existing electrical equipment and upgrading of electrical distribution systems to comply with today's standards has been neglected. It is the purpose of this paper to discuss the characteristics and applications of current-limiting fuses for the protection of existing electrical distribution systems and the maintenance problems associated with these systems, and to examine the advantages of fusible overcurrent protection for electrical systems in glass plants to be built in the future. The characteristics that are covered include fuse classes and types; fuse ratings; UL, NEMA, and ANSI standards; current limitation; selectivity; and coordination. Fuse characteristics are presented to assure the proper application of fusing for system components such as busway, cable, motor starters, circuit breakers, etc., against the high fault current distribution systems of today.     

Aging of polymeric and composite insulating materials. Aspects of interfacial performance in aging

Aging of polymeric and composite materials is reviewed mainly from the standpoint of their interfacial performance. Insulating materials can be divided into simple polymers and composites. Polymers for power cables, transformers, insulators and rotating machines consist of thermoplastics such as PE, PET and PPS, elastomers such as silicone, EPR and EPDM, and thermosets such as epoxy. Composites for GIS, rotating machines and insulators comprise epoxy/glass, epoxy/silica/alumina, and epoxy/mica systems. Aging processes are complicated in general, and take place under simultaneous multiple stresses such as electrical, thermal, mechanical and environmental stresses. Some of the phenomena covered in this paper are associated with the degradation by tracking and erosion and the loss of hydrophobicity in case of surface properties, and with PD, electrical treeing, water treeing and combined phenomena. The quality of cable insulation such as XLPE has been improved extensively from the standpoint of design electric strength. Interfacial problems will emerge for modification of cable joints. It is expected that polymers for outdoor use and filled epoxy resin systems should be improved from their environmental stability and from their design stress enhancement, respectively.     

特约文章：大型水电工程建设全过程数字化动态管控

大型水电工程建设过程中面临生产要素流动的复杂性,实物计量的准确性和实效性,以及参建各方管理体系、业务流程、工艺过程的差异性导致的前瞻性与实时性等管理问题。本文依托金沙江下游水电建设,以定位技术、移动应用和物联网等新一代信息化技术为手段,深入开展工程建设与信息化技术的融合研究,集成研发复杂环境下不同定位精度和响应速度的混合叠加定位技术,制定了水电建设各专业标准化工艺流程、管理表格及编码体系,开发移动在线应用系统,研发关键工艺智能技术和设备,构建贯通工程计价全过程的信息系统。项目成果确保了工程建设管理数据全面、真实、准确和实时的获取,实现了人员设备等流动性要素、质量安全等核心业务流程、混凝土浇筑温控及水泥灌浆等关键工艺过程、单元工程计量等真实实物成本在内的工程建设全过程数字化动态管控,促进了业务链、工序链等管理链的整体优化,为智能建造打下了基础,是工程建设智能技术的重要组成部分。     

电气监控系统(ECS)在火电厂(DCS)监控的探讨

具体分析了国内火电厂电气监控系统(ECS)的产生、发展以及电气系统纳入集散控制系统(DCS)的不同模式,通过比较确认"硬接线+通信"模式是当前火电厂电气系统接入DCS的主流解决方案。同时电气监控系统接入DCS控制的一些优点。随着电子信息技术的日趋成熟和稳定,完全取消硬接线的全通信方式必将逐步得到认可和规模使用。     

基于完善厂用电系统运行基础的探究

火力发电厂拥有众多的厂用电设备,为发电机组提供所需的能源,因此为确保机组的稳定运行,必须确保厂用电系统的安全可靠。针对某电厂1 000 MW机组从建设到投产运行期间,厂用电系统存在的几例影响系统可靠性的案例,分析原因和产生的影响,提出相应处理对策,并经实践证明是可行的。可为同类型机组的厂用电建设提供参考经验,以避免出现相类似问题,同时亦可作为经验交流,相互促进。     

Modeling and Management of Batteries and Ultracapacitors for Renewable Energy Support in Electric Power Systems–An Overview

Abstract—Energy storage devices and systems are playing a major role in all electrical systems from small electronics devices and automotive systems to the utility grid. The main objective of this article is to review energy storage devices, management, control, interface, and demonstrations for electrical power systems. Various types of energy storage systems are discussed, but the main focus is on batteries and ultracapacitors. Different types of batteries and their electrical models are explained. Three major types of ultracapcitors are also discussed. The battery management system and its functions, controls, and hardware are discussed. Various power electronics-based interface systems for battery and ultracapcitor charging and discharging are presented. Applications of energy storage systems for utility applications, including renewable firming, power shifting, and ancillary services, are discussed.     

Electrical Tapes: Which One Where?

As a result of the need for electrical component manufacturers to control inventory and reduce waste within their manufacturing processes, the selection of the correct electrical insulating tape is an integral part of cost-effective electrical component manufacturing.