Busway Short Circuit Testing Procedures

Every electrical system component must have recognizable predictable characteristics in order to be usable in today's modern electrical distribution system. The use of busways for power distribution in commercial and industrial buildings has become very popular in recent years due, in part, to the fact that it offers the requisite proven predictable electrical and mechanical characteristics. This allows the distribution system designer to use busway with confidence that it will perform as he intends. Of the many electrical and mechanical characteristics which must be evaluated, the busway short circuit rating has become one of the most important. This increased importance is the result of larger electrical services and lower loss supply equipment creating significant increases in available short circuit current levels. In addition, the present cost of equipment failure is at an all-time high. It is certainly better to spend a little extra (whether time or money) in the design and construction stages to provide maximum system performance under all conditions including possible short circuits.     

Training and qualifying your employees

Procedures alone cannot provide an improvement in electrical safety performance. Personnel who are exposed to electrical hazards must understand the basics of electrical hazards and safe work practices in order to implement the procedures. Training and qualifying your employees on these issues can be difficult and confusing. This article outlines a process for training employees on electrical safety issues. It will define "qualified" in terms that will satisfy the requirements of the Occupational Safety and Health Administration (OSHA) and NFPA 70E of the National Fire Protection Agency (NFPA) and also define the steps to meet the requirements of being qualified. The information contained in this article is the result of training the author has performed with electricians and nonelectrical personnel. The information is based upon the interpretation of the author. Employers should review the information and compare it to their interpretation of the regulations.     

Arc and flash burn hazards at various levels of an electricalsystem

This paper discusses the effect on humans of arcing and flashing from high-energy electrical equipment. It reviews the results of a survey of several large petrochemical facilities in the US about personal protective equipment (PPE) and other equipment used for protection from arcing and flashing. This paper also presents the results of calculations done for typical industrial and large commercial electrical distribution systems and supports the use of personal and other protective equipment for work performed on or near high-energy electrical equipment     

Power quality of small rural industries

Successful and economical operation of small rural industries (e.g. grain, dairy, irrigation, pig, poultry, beef feedlots, etc.) is a fundamental objective of society. However, when the performance and life expectancy of industrial electronic and electrical equipment is significantly affected by power supply anomalies caused by polluting loads at an industrial site and by utility normal operational activities, the economic benefits of this technology are quickly eradicated. This work presents the results of a detailed power supply quality survey of 23 small rural industries sponsored by the Canadian Electrical Association and provides a knowledge base on rural power quality and the possible origins of power supply anomalies. The major power quality problems experienced at the various industrial sites are summarized. The results of the survey provide a basis for mitigating actions by the electric utilities and their rural industrial customers to design and operate their electrical systems to minimize the effects of power supply anomalies     

Comparisons of the IEC and NFPA/ANSI Electrical Standards for Industrial Machines and Equipment

The International Electrotechnical Commission (IEC) has issued the second edition of Publication 204-1, Electrical Equipment for Industrial Machines. The National Fire Protection Association (NFPA) Committee 79 recently completed its work on the 1984 edition of the Electrical Standard for Industrial Machinery, covering metalworking machine tools, plastics machinery, and mass production industrial equipment. This standard is slated to replace the now dated Joint Industrial Council (JIC) electrical and electronic standards. These two publications will become the predominant standards relating to safety from electrical shock and fire in electrical equipment for industrial machines. Their basic aspects are described and comparisons between the major areas of these publications are drawn.     

浅谈国家标准GB／T11918修订的意义

国家标准GB／T11918．1和GB／T11918．2根据IEC60309的修订新版本进行修订，其中增加了IK抗撞击防护等级。国家标准第一次提出IK抗撞击机械防护等级，表明电器设备的防护已经引起各级的重视，说明IK抗撞击防护等级对于电器设备防护的重要性。本文阐述标准修订将进一步提高工业电器的安全性和可靠性；对于发展防护电器产业具有重要意义。     

Industrial Medium Voltage Cable and Switchgear Maintenance and Testing, Part I

Increasing costs of unscheduled production downtime in manufacturing industries, coupled with high costs for repair of electrical distribution equipment, dictate that planned electrical maintenance and testing play an important role in the industrial manufacturing process. Subject matter important to performing a planned electrical maintenance and testing program of medium voltage industrial cable and switchgear will be reviewed.     

Gas Insulated Substation Equipment for Industrial Applications

An electrical substation is an assembly of components used to direct the flow of electrical energy and, with interrupting and protective devices, to ensure the security of an electrical power system. Until recently the only available method for construction of high voltage systems was to use exposed air insulated equipment supported on porcelain columns. The past decade has witnessed the introduction and wide acceptance of compressed gas insulated equipment as a viable alternative to the conventional substation system. The characteristics of gas insulated substations (GIS) and their application for industrial use at service voltages at 69 kV and above are discussed.     

Industrial facilities gain new area classification guidelines

Both the United States National Electrical Code (NEC) and the Canadian Electrical Code (CEC) provide special rules for installing electrical equipment in hazardous (classified) locations. Hazardous locations are those locations where fire or explosion hazards may exist due to flammable gases or vapors, flammable liquids, combustible dust, or easily ignitible fibers or flyings. Only Class I materials (gases and vapors) are within the scope of American Petroleum Institute (API) RP500 and RP505. These recommended practices offer those in the petroleum industry an opportunity to standardize area classification drawings-both for drawings using the Division method of area classification and for drawings using the Zone method of area classification. Good engineering judgment must be used with RP500 and RP505, but guidelines provided should minimize differences of classifications by qualified individuals classifying the same or similar locations. This article provides an overview of the two recommended practices including outlines of tables of content, but primarily emphasising the substantive changes and additions     

An Interdisciplinary Course in Real-Time Computing

A need is arising for engineers who understand both an engineering discipline, and the use and capabilities of real-time computing equipment. This paper discusses the development, content, and implementation of an interdisciplinary course in real-time computing. Experiences in running this course will be compared to the normal electrical engineering course of similar content.     

基于GPRS和GPS技术的工业设备远程监测系统

结合全球定位系统和通用无线分组业务技术,设计并实现了一个应用于电力系统的远程监测系统.系统通过GPS模块实现对设备的定位,将定位信息通过GPRS数据网络上传到指定的监测平台,保障了工业设备的安全.     

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     

Ensuring that electrical equipment is safe for its intended use

The Occupational Safety and Health Administration (OSHA) regulations, the National Electrical Code (NEC), and several other nationally recognized standards and recommended practices indicate that electrical equipment must be inspected, tested, and evaluated to ensure that it is essentially free of hazards. This article guides the reader toward methods that will ensure that electrical equipment meets the safety intention of present day regulations, codes, and standards. The authors have experienced the situation where an electrical inspector, or a safety inspector, says that a particular piece of electrical equipment cannot be used because it does not have a label stating that it is listed by an nationally recognised testing laboratory (NRTL). The inspector's argument is that without such a label, he or she does not know if the equipment is safe for its intended use. The authors agree that one should try to purchase equipment with an NRTL label. But, if that is not possible, there are other acceptable ways to evaluate the safety of equipment and installations. OSHA allows two alternatives to listing and labeling. One involves the use of another federal agency, state, municipal, or other local authority responsible for enforcing occupational safety requirements. The other involves the use of manufacturer's test data, which the employer must keep     

Trends and Practices in Grounding and Ground Fault Protection Using Static Devices

Grounded and ungrounded systems are in general use in both commercial and industrial distribution systems. Proponents of each type of system have established valid points to defend their position. This paper briefly identifies the types of systems in use in each category and lists some of the main advantages and disadvantages of each. With the advent of higher voltage levels in our low-voltage distribution systems and the trend towards solidly grounded systems, problems resulting from the lack of proper ground fault protective devices have caused some severe equipment burndowns. The need for adequate protection has been recognized by the 1971 National Electric Code. This recognition is being complemented by Underwriters' Laboratories with the introduction of appropriate standards. With the passing of the Occupational Safety and Health Act of 1970, more emphasis than ever before will be placed on adherence to the preceding code and standards. This paper will review the various methods of detecting ground faults using static devices and describe some of the equipment available for these applications.     

基于谷歌眼镜的智能变电站实时数据展示与智能分析技术

研究了基于可穿戴设备(谷歌眼镜)的智能变电站巡检虚拟视频和实时数据展示技术:现场巡检人员通过谷歌眼镜扫描粘贴在电气设备上的QR码(二维码的一种)来自动识别相关电气设备的设备名称和ID编号,并将相关识别信息通过蓝牙技术转发给智能化一体单元;移动终端根据获得的设备编码,通过电力系统4G专网,从后台数据服务器搜索并获取该电气设备的关键物理信息(电气设备厂家,铭牌,上次检修时间及设备实时运行数据),并将信息根据现场巡检人员的需要以图片或虚拟视频的形式投影至谷歌眼镜上。本发明方法突破了常规变电站巡检难以有效获取实时数据的障碍,有助于提高智能变电站巡检的自动化水平。     

That's classified

The basic characteristic of oil and petrochemical industry processes is the use of flammable substances at high pressures and flows. Despite the strict requirements enforced to build process equipment that will be used in these industries, the high risk of accidents involving explosions and fires draws the attention of researchers because of the number of victims, material losses, and environmental damages. Locations where an explosive atmosphere may be formed are called "classified areas." Once these areas are identified, the technical specifications for electrical and electronic equipment and the development of specific operational procedures to ensure safety at work in these areas can be written and enforced.     

Progress in Japan in electrical insulation at high temperatures

It is expected that the use of electrical equipment at high temperatures will increase in the future, and the demand for heat-resistant insulation that can be used at temperatures above 300°C will increase. In addition, this high temperature electrical equipment will need to be higher in voltage and have a larger capacity. Accordingly, research and development will be needed to study the high temperature behavior of insulating materials, the insulation manufacturing process, and functional evaluation methods of insulation systems. Progress in Japan in R&D of insulation systems at higher temperatures is discussed     

An Energy Conversion Laboratory Using Industrial-Grade Equipment

Laboratory experiences are an important component of the education of engineering students. Rotating machinery laboratories assist with the visualization of the three-dimensional and rotating equipment. Contemporary use of rotating machines in industry often includes adjustable speed drives and digital controllers. Additionally, instrumentation is used to feedback electrical and mechanical variables to the drives and controls. Using an equipment grant from an industrial automation manufacturer, cost-effective laboratory workstations have been developed. Industrial-grade equipment is not designed for student experimentation but was adapted for this use. The workstations described in this paper incorporate modern power electronic-based drives and motors, electrical and mechanical sensors, and a computer-based control system with data acquisition. The advantages of these workstations include cost-effectiveness and the use of actual industrial devices that students might encounter in industry. Additionally, the workstations can be accessed by remote users, enabling off-campus students to also perform experiments on the workstations. The paper includes details of the workstation and its components, the data acquisition and control system, and sample experimental results.     

工业射线探伤室的电气设计

射线探伤是工业生产中重要的无损检测手段,广泛应用于石油、化工、电力、冶金、机械等行业。市场对超重、超厚设备的旺盛需求,促使国内多家装备制造厂建设更为先进的探伤室。高能射线对人体与环境具有伤害,射线防护是探伤室设计中的核心任务。文章从照明、配电、安全联锁、电气设备安装及管线敷设多个角度介绍了探伤室的基本设计原则,着重阐述了与射线防护相关的电气设计方法。