摘要:

The difficulties and complication associated with the transmission of large blocks of electric power over considerable distances have led, during recent years, to a growing interest in the possible application of direct current at high voltage for this purpose. In spite of the fact that alternating current lends itself readily to generation and potential transformation in bulk, it cannot compete with direct current where transmission on a similar scale is concerned. For this reason direct current can, under certain circumstances, form an economic link between the source of energy supply and the consumer.The paper presents a broad survey of the basic problems involved in generating, transmitting, and transforming electrical energy in the form of super-tension direct current as they appear at the present time, without attempting to add new matter to a subject which is of necessity highly specialized and the province of the transmission engineer.After a brief historical review of the subject has been given in the Introduction, the manifold advantages of high-voltage direct current as a means of power transmission are discussed and the factors limiting its direct generation are investigated.Of the several methods available for converting alternating current to direct current at high voltages, relatively few are at once technically and commercially feasible. A general account is given of those current-converting systems which seem to offer the most promising solution of the transmission problem.The general trend of opinion in favour of the super-tension direct-curent system as reflected in modern transmission projects is explained, and an outline is given of three such schemes of major importance which have been put forward during the last few years.Finally, the paper indicates the course of a rational future development and suggests how the super-tension direct current system of power transmission might with advantage be introduced and further technical data obtained.References to recent literature dealing with the transmission problem are given in a Bibliography.

DOI:10.1049/jiee-1.1934.0088

出版商:IEE    

年代:1934

数据来源: IET

DOI:10.1049/jiee-1.1934.0098

出版商:IEE    

年代:1934

数据来源: IET

摘要:

The increasing interest in their meter departments which is being shown by the managements of electricity supply undertakings is a matter for congratulation and is resulting in a very encouraging improvement in meter-engineering practice.In this paper testing-equipment design is discussed and the conclusion is drawn that primary resistance-regulated current-loading transformers can be satisfactorily employed. Good electrical performance is considered to be the most important feature of a single-phase meter; and a new method of testing to certify this feature is outlined. The merit of calibrating to special limits of error is discussed, together with routine methods of testing single-phase and polyphase meters.

DOI:10.1049/jiee-1.1934.0099

出版商:IEE    

年代:1934

数据来源: IET

摘要:

The paper describes a complete television system operating on the velocity-modulation principle. The theory, advantages, and limitations, of the principle are discussed, and it is shown how these limitations are overcome by the use of a further principle, that of intensification.The practical development of the system is described in detail, particular attention being given to the transmitting end, where the most fundamental problems are encountered. The results obtained to date (with single-channel wire transmission) are specified.The complete system is shown to be characterized by the following features:—(a) Absence of synchronizing problem in the line-scanning direction.(b) Simple solution of synchronizing problem in the picuture-traversing direction, including automatic framing.(c) Greatly relaxed modulation requirements on the receiving oscillograph.(d) Increased picture-brightness for a given receiving oscillograph as compared with the intensity modulation system.(e) Favourable concentration of detail in the light portions of the picture.(f) Nearly constant Percentage modulation of radion transmitter.

DOI:10.1049/jiee-1.1934.0102

出版商:IEE    

年代:1934

数据来源: IET

摘要:

The paper deals with the phenomena associated with the application of direct and alternating voltages to dielectric liquids. The possible explanations of the anomalous conduction-current and absorption-current components under continuous stress, and of the power loss in alternating fields, exhibited by such media, are discussed in terms of the evidences of recent research investigations.

DOI:10.1049/jiee-1.1934.0104

出版商:IEE    

年代:1934

数据来源: IET

摘要:

Outdoor measurements of power factor and impedance on various types of insulator strings are described and the results summarized. The best shape of insulator for unfavourable atmospheric conditions is discussed, and suggestions are made for further research.

DOI:10.1049/jiee-1.1934.0105

出版商:IEE    

年代:1934

数据来源: IET