Protection, metering, monitoring, and control of medium-voltage power systems

Traditional practices for industrial and commercial medium-voltage power systems to provide protection, metering, monitoring, control, power quality analysis, disturbance recording, and automation have changed. The new multifunction numerical protection relays using the processing power of the present generation of microprocessors have very high functionality. Many functions can be integrated into one device, allowing new power system problem-solving capabilities while permitting significant cost savings as compared with discrete protective relays, instruments, meters, recorders, and transducers of the past. This paper describes the vast capabilities and recent enhancements of these devices, which will be called intelligent electronic devices in this paper. Included are anecdotes obtained from an installation on a large industrial power system.     

Grades, Quizzes, Motivation, and Computers

The following paper describes the use of a simple FORTRAN computer program that may be used to determine course grades. The program is based on processing a set of IBM punched data cards. Each card contains the name of a student and all of his grades, including the final examination grade. The program may also be used to predict the final examination grade, based on previous quiz grades, and then, in turn, to predict the final course grade. It is thus possible to use this program periodically throughout the entire semester in order to provide the student, as well as the instructor, with a measure of his progress.     

Courts, technology, and the boundaries of expertise

Contemporary US jurisprudence is confronted with a constellation of issues that, while frequently masked as purely technical in nature, concern fundamental themes such as privacy and freedom of expression. Future court decisions will require an increased recognition of the ethical and social claims presented within technical contexts. This article is a study of comparative motion. On the one hand, there is the realm of technology where change is expected and unceasing. On the other hand, there is the law-embodying a tradition of rules and a methodology of interpretation which alters only slowly. The speed with which technology operates upon society is certainly a partial explanation for its clash with the more measured process of law, but it is not the only reason. The rapid generation of new knowledge is itself a force that challenges the stability of professions and philosophies, shifting claims of expertise among multiple contenders, sometimes with little warning. The power of expertise is not restricted to human beings. Rather than being situated solely within human agency, technology's “expert” ability to influence the decisions of courts is derived from its own character, is concerned with its own ends, and transmits values and purposes that are not necessarily consistent with human values or purposes     

History of optical trapping and manipulation of small-neutralparticle, atoms, and molecules

Reviews the history of optical trapping and manipulation of small-neutral particles, from the time of its origin in 1970 up to the present. As we shall see, the unique characteristics of this technique are having a major impact on the many subfields of physics, chemistry, and biology where small particles play a role     

Design,Analysis, Fabrication,and Testing of Laboratory Model of Transmission Line

This article presents a procedure for the development of a scaled-down laboratory model of a transmission line based on per unit. values of a true line. The X/R ratio of the model is kept same as that of the true line, as then only their performance can be compared. The current-carrying capacity of the scaled-down model is closer to 20 A to enhance its utility with different flexible AC transmission systems devices. A scaled-down model of a true line for which parameters are available in the open literature is fabricated, and a case study of its simulation and validation is presented. These studies show that the laboratory model is able to emulate closely the true line, and therefore, it can be fruitfully used for the dynamic study of the transmission line embedded with flexible AC transmission systems and hardware-in-loop simulation studies.     

Teh Philosophy, Design, and Development of Miartes

"Miartes" is a code name for a Missile Autopilot Research and Teaching Simulator designed initially to satisfy the requirement for a special-purpose analog computer on which the principles of missile control and automatic control engineering could be taught simultaneously. The simulator is based on the roll autopilot suitable for the hypothetical missile "Flying Shrew." A sophisticated flight envelope, extending in altitude from sea-level to 70 000 feet and in speed from Mach 1.0 to Mach 2.0, necessitates a novel approach to the computer design if rescaling is to be avoided. The sophisticated ffight envelope chosen vividly illustrates the need for some form of adaptive autopilot loop. The simulator is intended to supplement more complex specialized computers, and general-purpose analog computers in an integrated course involving several specializations. It has been found that the use of the "Flying Shrew" mathematical model has enabled a thorough integration between lecture room and laboratory to be achieved. Calibration of the simulator is directly in terms of missile autopilot parameters, and, since rescaling is avoided, the effective student absorption rate is at least four times greater than with older methods of teaching. The simulator is also an excellent basis for student design and research projects.     

Telecommunications, matter, and the formation of value

An examination is presented of how basic aspects of telecommunications and information transfer require a new understanding of the concepts of commodity value and its relationship to public policy. The main focus is on the creation of value in an increasingly information-based economic environment. Determinants of economic value for information commodities are revealed in the analysis of communication channels. The investigation draws upon the general nature of telecommunications and information transfer for principles governing commodity-value formation in both broadcast media and telephone-type resources. These are contrasted with value formation for material commodities. This model has broader implications for the issue of creating information as a social value from a limited range of formats and conventions. it is shown how, at the level of social policy, the role of standard and individual choice are becoming dominant as the realities of an increasingly information-based society have their impact on the values of the culture     

Origin, development, and design of K-factor transformers

Large rectifier transformers, because of the harmonics, always had to be specially designed to cope with the additional heating. But at that time there was no market or demand for 480 Delta-208Y1120 volt transformers to cope with the harmonic problem. Many people were aware of the problems with overheating but did not know the cause. In addition, average reading ammeters read too low when harmonic currents flowed in the neutral, and it rook true RMS meters to give accurate results. The problem was how to quantify the heating effect of harmonics. ANSI/IEEE C57.110, a guide for determining the heating effects of nonlinear loads, developed an equation for calculating the heating effects. By squaring the frequency and the per-unit current and multiplying them together, the guide arrived at a number without any designation. This was going to be called C for “constant”, but was decided against because of possible confusion with “centigrade”. The letter K for “Konstant” seemed reasonable to use, and Underwriters Laboratory accepted this designation in the original submission of a low voltage dry type transformer. K since became the standard measure of the ability of a transformer to withstand nonlinear loads. The features of the K-transformer are briefly discussed     

电机发展路在何方——低噪、节能、变频调速、智能、专用性

电机是大多数机械的动力源泉,在各种机构传动中起着举足轻重的作用。电机行业又是机械工业的重要组成部分,在国民经济中有着重要的意义。随着产业分工精细化、机械加工精密化及生产效率化,电机逐渐将向低噪、节能、变频调速、智能、专用性方向发展。     

Knowledge, data, and models

The object-oriented approach to integrating knowledge data, and models is examined. Under the object-oriented paradigm, everything is an object, which is itself an encapsulation of data and methods to manipulate and access the data within the object. Thus knowledge, data, and models can be defined as special kinds of objects. Active knowledge/data language (KDL), a functional object-oriented database system is considered, covering the active-KDL-type system and functions, and query-driven simulation     

Science, engineering, and humanity

This paper discusses the important role scientists and engineers play in societal prosperity. Today, as the gaps between societies, cultures, religions, and races widen and deepen at a frightful rate - enhanced by shortsighted and fundamentalist politicians - it is their obligation to actively foster intercultural contacts. Occasions for intercultural encounters are abundant in academia. In the academic realm, unconditional honesty forms the very first basic law that should not be violated under any conditions without grave consequences. The world sometimes might appear to be in a hopeless disarray that increases day by day. Nevertheless, scientists and engineers are asked to follow the advice of the great science philosopher Karl Popper that optimism is their duty and they are responsible for what will come.