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Generation, Transmission and Distribution, IEE Proceedings C

Issue 4 • Date July 1982

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Displaying Results 1 - 6 of 6
  • Torsional natural frequencies in the superconducting turbogenerator

    Page(s): 141 - 152
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (1411 KB)  

    In the design of superconducting AC generators the inner and outer rotors aie supported on thin torque tubes. This type of rotor structure introduces a torsional natural frequency, whereby the inner and outer rotor of the generator move in opposition, the frequency of which is influenced by the rotor electromagnetic structure. In this paper an analysis of the torsional natural frequencies within the turbine and generator is presented using eigenvalue techniques. The analysis is used to investigate the influence of the rotor structure on the frequency and damping of both the inter-rotor torsional mode and the rigid-body hunting oscillation mode. A simple formula for damping of rotor-hunting oscillations is presented. The eigen-value technique is also used to examine the influence of generator loading condition on the two oscillation modes. View full abstract»

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  • Coherency-based multimachine stability study

    Page(s): 153 - 160
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (809 KB)  

    A new equivalent generator model to replace a group of coherent generators is discussed. The model is simple and can easily be implemented in transient stability programs. Derivation of the parameters of the proposed equivalent generator does not follow the common approach of calculating a new set of parameters for a new or hypothetical generator. The model is derived in such a way that its dynamic equations correspond to those of one of the generators it represents. The approach to the derivation of the equivalent generator equations is general. In the paper the model is derived for application in two different stability programs. In the first program a conventional method of stability analysis is used which incorporates classical generator models. The second program involves a noniterative algorithm in which generators could be modelled with any desired degree of accuracy. As the equivalent generator incorporates the equations of one of the machines in the system, it is possible to model all generators and controllers, including the equivalent generator, with any degree of detail desired. While the main objective of the paper is to introduce the equivalent model and its mathematical derivation, application of the new technique to reduce the order of a power system is also demonstrated. View full abstract»

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  • Power-system simulator for testing energy-management systems

    Page(s): 161 - 165
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (738 KB)  

    The paper describes a software-based simulator which models an electric-power network, specially designed to test energy-management systems. The scope of, and the functions performed by, the simulator are described together with the modelling techniques which are used. View full abstract»

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  • Fault-current limiter with superconducting DC bias

    Page(s): 166 - 171
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (922 KB)  

    In the last decade there has been renewed interest in fault-current-limiting devices and various concepts are under active consideration. The paper describes the principle, design, manufacture and testing of a device based on one of these concepts. The possible areas of application of the device are indicated. View full abstract»

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  • Digital simulator of transformer windings subject to impulse voltage

    Page(s): 172 - 176
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (651 KB)  

    A digital simulator of transformer windings, which allows the computation of the transient responses to any input waveforms, is presented. Transformer windings showing a very irregular response with numerous resonant peaks are considered. The structure of the proposed simulator includes a transversal digital filter that uses the winding impulse response. This response is obtained analytically by means of an efficient algorithm requiring the knowledge of the frequency gain function which can be easily measured by means of instrumentation of high accuracy and low cost. The proposed algorithm includes a procedure for the computation of the phase response from the amplitude one. The design of the winding digital simulator of a 300 kVA transformer is carried out. The computed voltage pulse responses are in closer agreement with the measured ones. View full abstract»

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  • Electrical performance of aluminium/copper bolted joints

    Page(s): 177 - 184
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (1096 KB)  

    The 1350 aluminium/copper bolted joint is fundamentally less secure than the all-aluminium connection. Differential expansion shearing force at the interface is considered to be a significant degrading influence. As a consequence, substantial clamping pressures are needed in addition to having regard to surface preparation and bolting torques. Although inert greases are used at the interface to restrict corrosion outdoors, they do not improve joint stability. A hard plating, such as nickel, on the copper surface is advantageous, but softer deposits (e.g. thick electrotin or silver) cause rapid deterioration and are best improve the stability of the bimetal joint and eliminate the need for interface cleaning. View full abstract»

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