摘要:

This paper outlines a picture of the progress during the last seven years in the field it deals with, and also sets out the problems of to-day and the lines of possible future practice. The period under review has seen a change of national policy in Great Britain, which practically puts an end to isolated plants for public service, and enhances the scope for economy by the running of the largest plants with interconnections between them and all other plants and loads. New conditions therefore arise, demanding a reconsideration of the problems dealt with by the author in their earlier form in 1925.The construction of the various types of metal-clad switch-gear is diagrammatically represented by illustrations brought upto date and concluding with a forecast of the full application of the principle of complete enclosure and immersion of all conductors and insulators for all voltages as the means of safeguarding life and property, and securing continuity of supply.Certain basic constructional features are dealt with more fully. These are, in general, typical of changes, some brought about by research and practical experience, and others evolved in the quest by designers for something “different” in a period of intensified competition. An attempt is made to classify the prevalent forms of arcing contacts and busbar enclosures, and to state the effects of such details, particularly of the latter, on the general lay-out of the whole switching equipment.The use of metal-clad switchgear has of itself effected such economy in buildings that outdoor switchgear has not been widely used in Great Britain; but reasons are given in favour of outdoor construction.A review is given of the present position of rating, performance, and selection of circuit breakers, in order to lead up to a better understanding of the interpretation of these terms, and in view of the need for an international agreement on standard conditions for assessing ratings. Results of tests in a British 1500000-kVA testing station are recorded as examples.The need for economy is accepted as a fundamental object for the designer, but it should be effected by the reduction of components rather than by lowering the quality of details. Some ways and means of effecting economy along these lines are therefore proposed.The automatic isolation of faults has a particular bearing on the protection of property and supply; in the latter its performance in procuring stability is considered to be of paramount importance, and in the former its speed of operation is a criterion of equal merit. In the light of these principles the known protective systems are reviewed, and some new developments are mentioned. This study is in the main a history of the quest of the ideal, which, for the sake of economy alone, excludes the pilot cables of the earlier systems, and thus an opening occurs for the use of telephone pairs. Some original research is recorded for the avoidance of interference with the other uses of such telephone conductors arising from accidents on main lines. Further, the resistance of heavy arcs has been experimentally ascertained, with a view to making clear the necessity of using reactance instead of impedance as the true means of measuring distance for the accurate loaction and discrimination of faults in the distance types of proctection.The evolution of automatic and remote-control systems is traced from the earlier power-station control-room to the present-day design of regional control from a central room, and the forecast for the future favours the increasing application of mechanical principles, which in the first place tends to avoid errors, and in the second place takes over the responsibility of action in an emergency.

DOI:10.1049/jiee-1.1932.0107

出版商:IEE    

年代:1932

数据来源: IET

摘要:

When a wire rope is arranged in a laminated magnet yoke and magnetized by alternating current in accordance with the arrangement of magnetic circuit which has been described in a previous paper, †it is of importance to know how the magnetic flux becomes distributed across the section of the rope. In order to obtain some experimental data on this question, a sample of wire rope was constructed with a built-in search coil surrouniding each layer. By an examination of the oscillograms obtained from these search coils the flux density has been obtained for each layer of the rope for two values of the a.c. supply frequency. By means of ballistic tests the flux density has also been obtained for each layer when the wire rope is magnetized by direct current.

DOI:10.1049/jiee-1.1932.0113

出版商:IEE    

年代:1932

数据来源: IET

摘要:

After an introduction in which the need for high-speed oscillography and the nature of the problems are explained, an equipment built for recording the “uncontrolled” surges of a 1 000 000-volt impulse generator is described. Attention is concentrated on the problems of discharge tubes, beam traps, sweep circuits, and screening. Examples of the oscillograms obtained are given.

DOI:10.1049/jiee-1.1932.0114

出版商:IEE    

年代:1932

数据来源: IET

DOI:10.1049/jiee-1.1932.0115

出版商:IEE    

年代:1932

数据来源: IET

DOI:10.1049/jiee-1.1932.0117

出版商:IEE    

年代:1932

数据来源: IET