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Electrical Engineers, Proceedings of the Institution of

Issue 1 • Date January 1971

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Displaying Results 1 - 25 of 48
  • Inaugural address. The impact of advanced technology on the electrical industry

    Page(s): 1 - 8
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (1278 KB)  

    In the past 100 years, developments in electrical engineering and technology have brought about profound changes in human living standards. The increasing momentum of change presents serious challenges to man's ability to adapt himself to them. In the last 15 years the rate of technological advances in communications, power generation and utilisation, and in the application of electronic techniques, has been accelerating, and this is examined. The growth and development of the electrical manufacturing industries are discussed, and the effects on the industry of the rapid technical advances of recent years are considered. The changes which have already taken place are outlined, and the challenges of the future are analysed. Finally, the role of the engineer in management is discussed and the IEE is urged to help its members to acquire expertise in the managerial field. View full abstract»

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  • IEE Electronics Division: Chairman's address. Universities and technology

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    The functions of universities in respect of undergraduate courses, postgraduate courses and research are reviewed, and it is concluded that there should be greater variety of treatment in each case. Existing differences in the content and objectives of undergraduate and postgraduate courses should be stated more clearly to enable students to make sensible choices. Since the majority of future engineers are likely to be graduates, there is a danger that the advantages of the present interaction between graduate and industrially trained entrants to the profession will be lost. This could be avoided by reviving the Diploma-in-technology type of course with increased emphasis on design and production. Further expansion of student numbers should be used to create institutes of technology, concentrating on such courses and of strengthening the links with industry, for example by joint industry-institute staff appointments. Such staff should continue as effective members of industrial-design and production teams. The Lighthill Committee has advocated a concentration of research within large departments. Such a move would radically alter the nature of small departments. It is suggested that a swing to institutes of technology with a design and production emphasis would lead to a better overall solution. View full abstract»

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  • Qualitative analysis of 1st- and 2nd-order nonlinear networks

    Page(s): 19 - 28
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (1269 KB)  

    The paper presents several circuit-theory approaches for analysing the qualitative behaviour of nonlinear networks containing one or two energy-storage elements. The main concept consists in the transformation of a dynamic-network problem into an equivalent resistive-network problem. In particular, it is shown that any 1st-order nonlinear network can be analysed by obtaining the solution waveforms of an associated resistive constant-slope network. For 2nd-order autonomous nonlinear networks, it is shown that their isoclines are identical to the transfer-characteristic plots of an associated resistive isocline network. Many qualitative properties are shown to be derivable from this network. The classical approach for finding singular points, separatrices, and limit cycles is shown to have simple circuit-theory interpretations. The paper concludes with the presentation of three symmetry theorems useful for analysing 2nd-order nonlinear networks. View full abstract»

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  • Review of high-speed addition techniques

    Page(s): 29 - 35
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (860 KB)  

    A new large computing machine, the MU5, is under construction at Manchester University. As one aspect of the design of this machine, a review of available addition techniques was undertaken. This included both the use of special circuits for improving carry-propagation speeds, and the effects of restricted fan out and fan in on logical adders. The fastest adder uses a combination of block-carry and conditional-sum approaches and may be further improved by use of the sequential-state technique; emitter-coupled logic being used. Where economy is more important than speed, transistor-transistor medium-scale-integrated logic had advantages. Other techniques discussed include the saturated-transistor carry-path and serial-parallel adders. View full abstract»

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  • Radiation from a spherical antenna covered by a layer of lossy hot plasma. Theory and experiment

    Page(s): 36 - 42
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (735 KB)  

    A spherical antenna is covered by a finite layer of lossy hot plasma. The radiation of this antenna is quite different from that of the same antenna imbedded in an infinite plasma. The antenna radiation can be recovered or enhanced when the plasma frequency is increased beyond the antenna frequency. An electro-acoustic wave may be excited in the plasma layer and leads to some resonance. The electroacoustic resonances may lead to a very strong antenna radiation. A good agreement was obtained between theory and experiment. View full abstract»

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  • Small holes in a waveguide wall

    Page(s): 43 - 50
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (772 KB)  

    Equivalent circuits are presented for a small hole connecting a waveguide with a half-infinite space bounded by a metallic plane. The media on both sides of the aperture are allowed to be different. A short discussion of the influence of curved outer boundaries is given. View full abstract»

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  • Computer field-matching solution of waveguide transverse discontinuities

    Page(s): 51 - 63
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (1596 KB)  

    A computational method for solving a wide range of transverse waveguide discontinuity problems is described. Results are obtained by the simultaneous solution of matrix equations, generated by Fourier analysis, which relate the complex amplitudes of orthogonal electric and magnetic field components. In some cases, the solution is found to be sensitive to the way in which infinite series of field functions are truncated, and it is shown how the optimum form of truncation can be determined for many configurations of practical importance. Several examples showing the application of the method are given, and comparison of results with those obtained by experiment, and by other analytical techniques, confirms its accuracy. View full abstract»

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  • Measurements of transmission loss at high frequencies over 960 km temperate-latitude path

    Page(s): 64 - 78
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (1883 KB)  

    Signal strengths measured at a number of frequencies over a short-range (960 km) path between Lerwick, Shetland Islands, and Slough, England, are compared with those given by two well known prediction methods. Some of the assumptions inherent in the predictions, and their limitations when applied to the path under review, are examined. Suggestions are made for amendments to the methods. The measured signal-strength data are used to test the validity of wave-polarisation calculations and to give estimates of the ionospheric absorption for comparison with the absorptions indicated by the prediction methods. View full abstract»

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  • New development in lightning-counter design

    Page(s): 79 - 87
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (1126 KB)  

    Counters developed in Auckland use a combination of the electrostatic and radiative components of the electromagnetic field created by a lightning discharge. By combining the output of a CIGRÉ-type extra-low-frequency circuit with the lightning noise radiated in the 10 MHz region, counters have been designed which will respond to ground flashes only, or discriminate between ground and cloud flashes, and at the same time resolve a multiple ground flash into its individual strokes. In all these applications, the gap in the high-frequency noise occurring after a ground stroke has been utilised in the discrimination between the different types of lightning discharge. View full abstract»

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  • IEE Power Division: Chairman's address. Let there be light

    Page(s): 89 - 98
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (1862 KB)  

    Appropriately to the centenary year of the IEE, the paper reviews the past 100 years of the distribution and utilisation activities of the electrical-power industry. With their origins back in Faraday's momentous discovery of electromagnetic induction in 1831, the enoumous electrical-power industrieds of today have been built on the brilliant inventions of the past. The latter half of the 19th century saw the exploitation of the dynamo, the arc and incandescent lamp and the electric motor. At the end of that period, the new supply utilities had a reliable and economic means of production, namely the dynamo, and a diversified load with motors added to lighting. The `battle of the systems¿ at this time resulted in the predominance of a.c., given an imperishable lead by the young Ferranti's concept of larger-scale central generation at high voltage. Combined with Parsons's inverntion of the steam turbine, generation by turboalternators in central stations holds gool to this day. Many of the fundamental principles and basic materials for transmitting, controllong and measuring date from this time, although steady advances in design have brought them to an efficiency undreamed of in those days. The continuity of development is traced and projected into the future, in the scope for research, for management, for the profession, and in the exercise of social responsibility. View full abstract»

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  • Artificial- and natural-pollution tests on outdoor 400 kV substation insulators

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    Pollution tests have been made on a range of 400 kV substation insulators using both natural- and artificial-pollution methods. Agreement between the results of the different test methods is good. The effects of various design parameters on insulator pollution performance have been evaluated. View full abstract»

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  • Optimum hydroelectric-power-generation scheduling by analogue computer

    Page(s): 110 - 116
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (736 KB)  

    The use of an analogue computer for short-term optimum hydroelectric-power-generation scheduling is presented. The optimum objective is to minimise the instantaneous energy taken from the system reservoirs, subject to satisfying a predetermined load demand. All downstream stations on a river system are treated as run-of-the-river types. Flowtime delays between stations are neglected in the optimising process, and nonconforming loads are treated as negative generators. View full abstract»

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  • Transient-recovery voltage characteristics of a 3-phase power system

    Page(s): 119 - 124
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (676 KB)  

    The application of R, S, T components to solve faults in power systems and transient unbalances in power networks has been attempted, to simplify the problems to a greater extent than other components, such as Clarke's or Concordia's components. However, these attempts were not completely successful, because the equivalent circuits developed to represent various types of faults did not completely eliminate the use of isolating transformers, which was an objection to a study of the above problems in a network analyser. The introduction of isolating transformers placed certain limitations in representating power systems under changing fault conditions in a transient analysis. It is the purpose of the paper to introduce the modified equivalent circuits in such a way that they completely eliminate the use of isolating transformers, without any need to modify the original equivalent circuits. A systematic analytical approach is also developed for the determination of the transient-recovery voltage characteristics, by illustrating the various steps with a typical fault. View full abstract»

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  • Solution of large power-system networks by ordered elimination: a comparison of ordering schemes

    Page(s): 125 - 134
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (1248 KB)  

    A variety of different ordering schemes are used with sparsity-programmed Gaussian elimination to solve a range of practical power-system networks, with a view to assessing their relative merits for general-purpose applications. It is shown that, for networks of the sizes and types studied, the choice between the more successful schemes is dependent mainly on the relative amounts of work required to establish the orderings. One simple and popular scheme, involving pivot selection at each stage of the elimination process on a row-sparsity basis, emerges as the most attractive. View full abstract»

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  • Triac phase control with a line-frequency control signal

    Page(s): 135 - 138
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (447 KB)  

    A triac control circuit is presented which provides continuous (phase) control in response to the amplitude of a sine-wave signal of line frequency. Such signals might be obtained from a variety of a.c. transducers; e.g. from a resistance thermometer in a line-frequency bridge. A negative-resistance circuit is used which increases the control voltage exponentially to the trigger level for small signals. General curves are presented for conduction angle and power output as a function of signal amplitude. View full abstract»

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  • Effect of load power factor on current-transformer performance

    Page(s): 139 - 142
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (381 KB)  

    The current transformer, for metering as well as protection, may not, in practice, have a purely resistive load. In certain special applications, the load is inductive, e.g. oscillograph coils etc., and, when the control cables are very short, it is possible that the load may have a power factor of less than unity. The steady-state and transient fluxes under these conditions are analysed. The effect of the load power factor of the current transformer on the errors is presented. The equations developed in the paper are directly helpful in forecasting the performance of a current transformer when connected to a nonresistive load. View full abstract»

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  • Transient performance of doubly excited synchronous machine

    Page(s): 143 - 147
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (511 KB)  

    The paper describes an investigation of the transient behaviour of a doubly excited synchronous machine, both with and without excitation controls. The analysis shows how the positional change of the resultant rotor m.m.f., due to the induced currents, gives an inherent advantage to the doubly excited machine over a conventional synchronous machine, for the improvement of transient stability. When excitation controls are employed, there is a further improvement in the transient-stability limit, with a greater contribution coming from the voltage regulator. View full abstract»

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  • Effects of subharmonics and winding asymmetry on the performance of slip-ring machines

    Page(s): 148 - 152
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (625 KB)  

    The acceptable level of subharmonics in the m.m.f. waveform of primary windings for slip-ring induction motors has been investigated, and certain maximum tolerable levels are here determined which, if exceeded, seriously affect the performance of slip-ring machines. It has already been established that surprisingly large subharmonics in the m.m.f. waveform of a squirrel-cage induction motor can be accepted without perceptible effects on the machine performance. In large single-speed machines, with relatively large numbers of slots per pole, there is little diffculty in minimising subharmonic m.m.f.s. The design of change-speed pole-amplitude-modulated (p.a.m.) windings is more difficult in this respect; but, with the aid of recently developed techniques, remarkably harmonic-fee windings can be obtained, given a sufficient number of slots per pole. It is in smaller units that the design problem is most severe, and that large subharmonics might inhibit the development of change-speed slip-ring motors. There are, however, certain unorthodox windings, two of which are described, which may be used successfully as secondary windings, in conjunction with primary windings which might otherwise be unacceptable. View full abstract»

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  • Digital simulation of a synchronous generator in direct-phase quantities

    Page(s): 153 - 160
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (773 KB)  

    The paper describes a mathematical model for the simulation of a 3-phase synchronous machine using direct-phase quantities, thus obviating the need for any transformation. Numerical solution using a digital computer has also been described, and compared with digital simulation in transformed d-q-0- and ¿-ß-0-axes models of a synchronous machine. The proposed model in direct-phase quantities enables a unified approach to be adopted in the study of both symmetrical and asymmetrical conditions. Since the constraints to be imposed are direct operating conditions, asymmetrical operating conditions can be studied very easily. Modifications required in the model to simulate various types of faults are described. Versatility of the proposed model is illustrated by the study of a single-line-earth fault with single-phase opening and automatic reclosure. It is shown that this type of fault can be studied as simply as, say, a 3-phase fault. View full abstract»

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  • Line-line short circuit of synchronous machine: illustration of computer-aided machine analysis

    Page(s): 161 - 168
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (749 KB)  

    The sudden unbalanced short circuit of the 3-phase synchronous machine constitutes one of the most difficult problems of conventional machine analysis, whether traditional or unified. It is, however, readily susceptible to numerical integration using digital computers. The general approach, which is believed to have a wide application, is illustrated by the simple case of the 2-winding single-phase machine, and is then extended to the practical problem of the salient-pole machine with damper windings. Predicted and test results are found to be in good agreement. View full abstract»

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Aims & Scope

The Proceedings of the Institution of Electrical Engineers was published by the IET between 1963 and 1979.

Full Aims & Scope