DOI:10.1049/ji-2.1944.0019

出版商:IEE    

年代:1944

数据来源: IET

摘要:

After reviewing the characteristics of the high-voltage supply which is required for use in meter testing stations established under the Electricity Supply (Meters) Act, 1936, the paper describes the construction and gives the theory of a stabilizer which has been designed to provide current at a voltage so constant that it greatly facilitates precision measurements on voltmeters and wattmeters. Some other uses for the apparatus are described.

DOI:10.1049/ji-2.1944.0020

出版商:IEE    

年代:1944

数据来源: IET

摘要:

The paper opens with a description of a simple form of co-ordinate a.c. potentiometer which requires little power to operate and is very light and portable. Its application to the measurement of the ratio and phase errors of a voltage-transformer follows. It may also be used to measure the errors of current-transformers, and several methods are described which avoid the difficulties inherent in the more usual “spill current” methods. Brief notes of the construction of an oil- cooled, shielded resistor for 33 kV, and of two standard current-transformers, are given.

DOI:10.1049/ji-2.1944.0021

出版商:IEE    

年代:1944

数据来源: IET

摘要:

The paper deals mainly with the MVA rating or the power factor rating, and with the synchronous-reactance value of large, non-salientpole synchronous generators. Essential factors for selecting these values are discussed and a method of making that selection is proposed. An analysis is made of the manner in which the two values affect the operation of the generator. From a power chart based on the classical circle diagram, diagrams of “working area” limitations are derived and represented in co-ordinates of reactive power versus active power, power factor versus active power and excitation current versus active power. These diagrams are suitable both for comparing properties of different generators when ordering new units, and for supervision of operation of generators. Problems of capacitive loads and of synchronous stability of generators are discussed. From a comparison of external characteristics of an isolated generator, with different load characteristics, conceptions of voltage stability and of “absolute power limit” in respect of that voltage stability are derived. The influence is discussed of stator-winding resistance and of saturation on representative diagrams and curves. The paper is illustrated by an example of an actual 50-MW, 58-MVA turbo-generator.

DOI:10.1049/ji-2.1944.0022

出版商:IEE    

年代:1944

数据来源: IET

摘要:

Physical and economic ratings are compared, and the scope and limits of economic choice are discussed and illustrated. A method of economic selection is proposed through the use of larger standard machines, and a technique is developed for investigating the economy of changes in rating. Tables of data and results are given at the end of the paper, and the methods employed in these tables are explained in some detail. The results are expressed in the form of an “economic advantage” obtainable through under- or over-running, and show the former to be highly advantageous in a large number of cases. Methods of implementing the results are discussed.

DOI:10.1049/ji-2.1944.0023

出版商:IEE    

年代:1944

数据来源: IET

摘要:

Technical developments may at any time make it possible to increase the working densities in our electrical machines, and so enable a larger output to be obtained from a given frame-size and weight of active materials. This paper assumes that an increase of transformer flux density is technically feasible, and tries to discover whether it is economically desirable. Only a single situation, and only two (fairly large) sizes of transformer such as would be used on the lower-voltage sections of the Grid, are examined. The results are emphatically against any such increase, and in favour of lower densities than those in use at present.The economics of higher-grade steel is briefly examined.

DOI:10.1049/ji-2.1944.0024

出版商:IEE    

年代:1944

数据来源: IET

摘要:

The paper consists of two parts. The first is devoted to a comprehensive review of overhead-conductor sags and tensions and their calculation on single spans and on complete lines, using parabolic formulae throughout. A standard procedure and standard methods of calculation are recommended.The second part of the paper deals with the determination, from the point of view of the conditions prevailing in Great Britain, of wind and ice loads to be applied to conductors for design purposes and the stresses so produced in the conductors. The use of the term “factor of safety” when applied to overhead conductors is criticized, and suggestions are offered for revisions to the Overhead Line Regulations of the Electricity Commissioners. The loads transmitted to the supports are also considered. Erection sags for low-voltage distribution lines are recommended for general adoption.

DOI:10.1049/ji-2.1944.0029

出版商:IEE    

年代:1944

数据来源: IET

DOI:10.1049/ji-2.1944.0030

出版商:IEE    

年代:1944

数据来源: IET