摘要:

The address is concerned with the public distribution of electrical energy in the UK from voltages of 132 kV down to the consumers' voltage of 415/240 V. Reference is made to consumers' requirements in an industry that has to be operated 24 h a day throughout every day of the year. The importance of forecasting future demands, and the related investment for the industry as a whole, which over the years has reached formidable proportions (getting on for some £10000 million) are highlighted. The latest and most up-to-date practices in distribution engineering are then fully described, starting with the e.h.v. system, in both urban and rural situations, and progressing downwards to the m.v. systems supplying over 19 million consumers in England and Wales. The address then deals with the principles and practices of system planning, system protection and control and communications. Supply reliability and quality of supply, standardisation of systems and equipment, and harmonisation with EEC standards are suitably represented, as is the important matter of amenity. Reference is also made to innovation, research and the growing computer applications. Finally, some of the more important changes in equipment, such as the design of switchgear, transformers, cables, overhead lines and protection, are recorded.

DOI:10.1049/piee.1974.0001

出版商:IEE    

年代:1974

数据来源: IET

摘要:

Telecommunication systems depend for much of their effectiveness on a high degree of standardisation on a worldwide basis, so that calls can be made from virtually every subscriber in the world to any other. Although there is competition in the supply of equipment, the basic principles of collaborative interworking remain mandatory. In computers there are often only minimal areas of comparable standardisation. Even high-level languages are often particular to a machine or a manufacturer, and computer users are frequently unable to run programs written for one machine on a different machine from the same maker. A high degree of mutual dependence is now coming into existence between telecommunication systems and computing systems. Examples are now widespread of computer-like machines being used to control or assist communications plant, and of telecommunication networks being used to link computers together. In addition, a substantial possibility exists of technology developed for computers, often leaders in electronics techniques, being applied to communications uses. Moreover, the ability of even modest telecommunication systems to maintain reasonable service in the presence of faults suggests that this ‘system’ level of organising reliability could with advantage be incorporated into some computing systems.

DOI:10.1049/piee.1974.0002

出版商:IEE    

年代:1974

数据来源: IET

摘要:

The paper describes a thermal convertor mounted in a 50 Ω coaxial line, which consists of two thin resistance films heated by the electric current being measured, with a high-sensitivity thin-film thermocouple attached to the midpoint of each resistance film to give the temperature rise at that point. Both the heater and the thermocouple are deposited on a substrate and insulated from each other; thus it is described as an ‘indirectly heated thermocouple’. The thermocouple is made from n- and p-type germanium films and produces a d.c. output of 1 μV at −40 dBm power level. The thin-film thermoelectric transducer can be calibrated in terms of d.c. power dissipation, and gives measurements of power in the range −40 to +20 dBm with an accuracy of within ±2% at frequencies of 0–1 GHz. Comparison of the performance of the device with other measuring instruments indicates that it is of acceptable accuracy, even at microwave frequencies up to 11 GHz. Moreover, it was found that measurements of −50 dBm were possible by this device provided that effects of the thermal noise and drift of the transducer were eliminated by digital integration and differentiation circuits. Errors arising in these measurements are also discussed.

DOI:10.1049/piee.1974.0003

出版商:IEE    

年代:1974

数据来源: IET

摘要:

A new and systematic technique has been developed for the realisation of nth-order-indefinite admittance matrices as earthed structures by the 2-element-type networks that are without any transformer. There is no restriction on the number of permissible poles present in the admittance matrices. The technique is based on suitably partitioning the residue matrices, and sharing them with the other terms present in the indefinite admittance matrix, so that each partition yields a realisable network on inversion. The necessary and sufficient conditions for this type of realisation have been stated, and the relevant theorem is proved. The technique is definite, and simple. It has a great utility for multiport-transfer-function synthesis. Numerical examples have been given to illustrate the synthesis procedure.

DOI:10.1049/piee.1974.0004

出版商:IEE    

年代:1974

数据来源: IET

摘要:

Two ladder-structure recurrence formulas have been suggested for the analysis of a nonuniform distributed network. An array has been established to form the approximate circuit polynomials in the S domain for studying pole-zero behaviours of this network.

DOI:10.1049/piee.1974.0005

出版商:IEE    

年代:1974

数据来源: IET

摘要:

The problem of finding the distribution that produces the best mean-square approximation to a given far-field pattern has been solved exactly for a number of nonplanar apertures, subject to a restriction on the Q factor of the aperture.

DOI:10.1049/piee.1974.0006

出版商:IEE    

年代:1974

数据来源: IET

摘要:

The address concerns itself with the transmission of electrical power in bulk underground principally at the voltages of 132 kV and higher. It states the basic problems of an underground system starting from the needs of the usual tortuous route and ending with the rating and high cost difficulties. There follows a review of current approaches setting these against the historical background. First, it concentrates on the severe mechanical difficulties of producing High grade cable Insulation, with paper as an Insulant, In an extremly flexible form, goes on to describe the special nature of the accessories needed to solve the electrical and pressure-retaining requirements and then deals with the many special rating solutions which are now being adopted to meet the growing demand for high MVA circuits. Bearing in mind the high relative cost of high-voltage cable much research and developement work has been in the field of the economy and the address makes reference to the many approaches. An approach is made to the problem of a transmission system which, ab initio, needs to be visualised as largerly underground and points out the strong case for d.c. transmission.

DOI:10.1049/piee.1974.0007

出版商:IEE    

年代:1974

数据来源: IET

摘要:

The problem of forecasting the integrated-load demand of an interconnected power system is studied. It is proposed that the harmonic-series model for the weekly load pattern be expressed in the state-variable form. This then permits the use of Kalman-filtering techniques, for load-prediction purposes. It is shown that this approach leads to an improvement in the forecasting reliability, without increasing the online computational requirements. The results of a particular study are also presented.

DOI:10.1049/piee.1974.0008

出版商:IEE    

年代:1974

数据来源: IET

摘要:

Cogging torques can be made negligibly small by a correct choice of design parameters for induction motors. The method of analysis has been described in earlier papers, and it is shown here that simple rules can be derived for the effective elimination of the cogging tendency without recourse to slot skewing. The rules are not so restrictive that they cannot be applied to most machines in conjunction with other criteria for the choice of slot numbers.

DOI:10.1049/piee.1974.0009

出版商:IEE    

年代:1974

数据来源: IET

摘要:

Our modern society depends for its existence on the unrestricted availability of highly developed and sophisticated technology; but to enable such a society to develop, certain basic requirements must be fulfilled. The most important of these is an adequate and reliable supply of water, not only to sustain life but also to satisfy the needs of industry and commerce. Secondly, a common language is necessary for ideas to be exchanged and agreements reached. Finally a comprehensive educational system must be provided, oriented to the specific needs of the people and its country. The modern State of Israel illustrates how these basic requirements have been met through the application of technology to transform a poor, backward country into a flourishing industrial society. The Hebrew language was revived, and a technological university—Technion—was founded. In the 50 years since the first classes started, its facilities have been applied to all aspects of the growing economy—especially in the areas of water and irrigation systems—allowing progress to be made that could not otherwise have been achieved.

DOI:10.1049/piee.1974.0011

出版商:IEE    

年代:1974

数据来源: IET