摘要:

The paper shows the principles on which analogue computers, accepting as input data the singularities of a rational function, may be designed to display together the Nyquist diagram, theQ-diagram and the step-function response of a linear servo system having one dominant closed loop.It describes a simple model which has been built on these principles and gives some time and frequency functions computed by the model for certain patterns of singularities.

DOI:10.1049/pi-2.1952.0122

出版商:IEE    

年代:1952

数据来源: IET

摘要:

A certain type of hydraulic remote position controller contains two resonant systems in its sequence. These are caused by the presence of resilience in the shaft connecting oil motor and mechanical load and by hydraulic resilience of the link between oil motor and oil pump.An idealized analysis of the system yields a sixth-order linear differential equation. When equalizing networks and possible non-linear effects are considered, the solution of the system equation by mathematical methods over a large range of parameters becomes impracticable.To ease the problem of computation an electronic simulator was designed. The paper includes a description of the simulator, and also an outline of the experimental work carried out to check its performance.

DOI:10.1049/pi-2.1952.0123

出版商:IEE    

年代:1952

数据来源: IET

DOI:10.1049/pi-2.1952.0127

出版商:IEE    

年代:1952

数据来源: IET

摘要:

The realization of high-voltage d.c. transmission has been prevented by the lack of reliable rectifiers and inverters, although the possibilities of mercury-arc-convertor operation up to 100 kV and 100 MW have been demonstrated by some test installations surveyed in the paper. The same type of valve may be used for both rectification and inversion; the stresses present during both operations are analysed in terms of the random failures which have so far prevented a large-scale practical transmission.High-voltage operation by means of series-connected low-voltage valves is prohibitive, and no more than three valves should be used in series. However, experience has shown that a series of gaps within a single envelope can be used for very-high-voltage conversion. The basic concept of forced voltage subdivision of the anode space is examined, and the conditions necessary to ensure sufficiently high breakdown thresholds are outlined. None of the present high-voltage valves fulfils all the requirements for trouble-free operation, owing to the various phenomena which lower the threshold and cause random failures.Therefore, a valve is described which is expected to meet these requirements, and which, when used in a 3-phase 6-pulse bridge, is designed to convert 250 MW of power at 250 kV. No radically new concepts are involved; the proposed techniques extend modern rectifier experience but will require careful development for the large dimensions.The paper concludes with a brief survey of the anticipated performance of the valve under backfire conditions, of the auxiliary and control devices necessary, and of the future trends of development.

DOI:10.1049/pi-2.1952.0129

出版商:IEE    

年代:1952

数据来源: IET

摘要:

The 1951 Presidential Address included reference to 275-kV developments on the British Grid system and the paper forms an interim report of progress made by the British Electricity Authority on this project. Part 1 sets out briefly the basic investigations carried out which established the technical necessity and economic justification for the new system, the main outlines of the scheme proposed and the operating voltage. Part 2 deals with some of the research on losses and radio interference at high voltage, which, following earlier work, have had a significant bearing on the selection of the size of conductors and insulation characteristics. Part 3 describes the progress made in settling specific design and performance characteristics which have been incorporated in detailed specifications. Contracts have been placed with British manufacturers for substantial sections of this scheme, the first stage of which is due to be in commission by 1955.

DOI:10.1049/pi-2.1952.0133

出版商:IEE    

年代:1952

数据来源: IET

DOI:10.1049/pi-2.1952.0142

出版商:IEE    

年代:1952

数据来源: IET

摘要:

A brief review is given of the historical development of power and power-factor measurements in balanced polyphase systems. Then follows the general theory of two distinct schemes for such measurements upon balanced systems having no neutral. One of these schemes is a generalization of the well-known indirect two-wattmeter sum-and-difference method, and the other is a direct scheme in which the active,P, and reactive,Q, powers are measured separately. The 2-phase systems are discussed briefly. A fairly comprehensive bibliography is given.

DOI:10.1049/pi-2.1952.0143

出版商:IEE    

年代:1952

数据来源: IET

DOI:10.1049/pi-2.1952.0144

出版商:IEE    

年代:1952

数据来源: IET

DOI:10.1049/pi-2.1952.0145

出版商:IEE    

年代:1952

数据来源: IET