摘要:

Following a brief résumé of available information on the wave-shapes of surges on transmission lines, the wave-shapes of impulse voltages generated in the laboratory are denned and recommendations are made for the standardization of wave-shapes in order to facilitate the comparison of results obtained in different laboratories. Standardization of impulse-testing technique is also advocated. Sparkover and puncture tests are considered in detail, and the extent of agreement of results obtained in different laboratories is indicated.Standard impulse-voltage routine and type tests are recommended for line insulators, bushings, switchgear, and transformers, and reasons are advanced for the choice of such tests. The repercussion of the introduction into national specifications of impulse-voltage testing on the existing standardized power-frequency tests is considered in detail, and recommendations are made for the elimination of some of those tests. In order to establish co-ordination between line and station apparatus under impulse voltages, a table is given showing the suggested impulse test voltages for station apparatus connected to normally-insulated transmission lines, the proposed test values being based on the British Standard Specification for line insulators now widely in use.

DOI:10.1049/jiee-1.1936.0043

出版商:IEE    

年代:1936

数据来源: IET

DOI:10.1049/jiee-1.1936.0048

出版商:IEE    

年代:1936

数据来源: IET

摘要:

It is the aim of this paper to consider broad principles rather than manufacturing details.The performance characteristics of voltage transformers are deduced from general fundamental principles, and expressions are derived for calculating ratio and phase errors from design data.Two methods are given for determining errors on and desired burden from a knowledge of previously ascertained test data. The first method is based on ordinary graphs of errors against output, and the second method employs a simple geometrical construction based on the transformer vector-diagram.Several questions concerning the construction and practical application of voltage transformers are considered, including typical performance characteristics, voltage transformers for high frequency and high accuracy, winding connections, fuses, limiting resistances, and breakdowns, and a comparison of dry, oil-immersed, and compound-filled types.Testing is subdivided into general routine testing and testing of ratio and phase errors. Descriptions are given of two equipments for testing errors. One equipment employs a resistance potential-divider and is capable of testing ratios up to 200. The other equipment employs as potential divider a high-voltage condenser in series with a resistance and is capable of testing ratios up to 2 200.The paper concludes with some remarks on testing of errors under actual working burden, and on the effect of resistance of secondarv leads on errors.

DOI:10.1049/jiee-1.1936.0049

出版商:IEE    

年代:1936

数据来源: IET

摘要:

A neutral displacement due to abnormal system conditions (other than short-circuits) is known by the name of “neutral in version”. This can occur as a result of open circuits in one or more phases of systems possessing inductance and capacitance, or owing to special conditions of neutral earth connections.A general formula is developed for the position of the neutral point on any system of any number of phases, balanced or unbalanced. This is then applied to deduce the neutral displacements occurring as a result of open circuits on systems fitted with neutral-earthing transformers and Petersen coils or arcing-earth suppressors.The possibility of neutral inversion on certain types of balanced system, even without open circuits, is demonstrated and a qualitative consideration of the phenomena is given.Finally, instances are mentioned of neutral inversion which has occurred in practice, and remedies are indicated, together with a summary of system arrangements to be avoided in design.

DOI:10.1049/jiee-1.1936.0051

出版商:IEE    

年代:1936

数据来源: IET

摘要:

This paper is concerned chiefly with a discussion of whether or not the anode stream of a thermionic valve produces a component of fluctuation voltage equal to that which would be produced by a metallic conductor of equal resistance at the cathode temperature. In a recent paper, G. L. Pearson has shown that when the anode current is very small, the fluctuation voltage is equal to that in a metallic conductor of equal resistance at a temperature about half that of the cathode.In this paper it is shown that when the anode current is very small a familiar expression for the shot voltage assumes a form suggestive of a thermal-agitation voltage in a resistance at half the cathode temperature. This form is due to the dependence of anode current on cathode temperature when the anode is negative. Thus it would seem that Pearson's work does not necessarily prove that the anode stream is the seat of a thermal-agitation voltage: his results can equally well be interpreted as a shot-voltage effect, and such interpretation gives a direct explanation of why the relevant temperature is only half that of the cathode.

DOI:10.1049/jiee-1.1936.0052

出版商:IEE    

年代:1936

数据来源: IET

DOI:10.1049/jiee-1.1936.0053

出版商:IEE    

年代:1936

数据来源: IET

DOI:10.1049/jiee-1.1936.0054

出版商:IEE    

年代:1936

数据来源: IET