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Generation, Transmission and Distribution, IEE Proceedings C

Issue 5 • Date Sep 1989

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Displaying Results 1 - 8 of 8
  • Effect of excitation systems and of power system stabilisers on synchronous generator damping and synchronising torques

    Publication Year: 1989 , Page(s): 264 - 270
    Cited by:  Papers (3)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (528 KB)  

    The synchronising and damping torque coefficients in the range of the electromechanical oscillation frequencies provide a measure of the generators' contribution towards power system stability under small deviations, and may be taken as stability indices even for multimachine systems, although their interpretation is rather complex in this case. The author presents the development of an expression to calculate the electromagnetic torque for small deviations around an operating point, as produced by a synchronous generator connected to an infinite busbar through an impedance; he explicitly includes the effects of its automatic voltage regulator (AVR) and of the additional stabiliser signal derived from the rotor speed View full abstract»

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  • Effects of active and reactive power modelling in optimal load flow studies

    Publication Year: 1989 , Page(s): 259 - 263
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (476 KB)  

    Optimal load flow normally considers active and reactive power loads as independent of the voltage level. The exponential form of a static load model relating the active and reactive power components to the busbar voltage, is considered and the effects of incorporating this load model in the optimal load flow solution of several test systems are studied. The effects of modelling active and reactive powers are considered separately as well as when taken together. The results are compared with the respective standard optimal load flow solutions for a number of standard test systems View full abstract»

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  • Signal processing and discriminating techniques incorporated in a protective scheme based on travelling waves [power lines]

    Publication Year: 1989 , Page(s): 279 - 288
    Cited by:  Patents (2)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (652 KB)  

    The incorporation of correlation techniques in a protective scheme for transmission lines based on travelling waves is described and it is shown that important features of signals arriving at the relaying point can be extracted, even from complex waveforms, using correlation techniques. The influence of window length on detection accuracy is also investigated. The results are used in a protective algorithm, previously described by the authors, to obtain reliable relaying information. A method for dealing with close-up faults is also presented together with a range of results showing the discriminating ability of the algorithm View full abstract»

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  • Fast and efficient gradient projection algorithm for dynamic generation dispatching

    Publication Year: 1989 , Page(s): 295 - 302
    Cited by:  Papers (5)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (732 KB)  

    A gradient projection algorithm is presented for the dynamic dispatch of thermal generations, based upon an active set strategy and exploiting second order information in determining the descent directions. The algorithm is adapted to the model of the dynamic dispatch problem which consists of the minimisation of a nonlinear objective function subject to quadratic equality constraints and linear inequality constraints. The envisaged algorithm can be applied to the dispatching of thermal units during the steep load pick-up and drop-down periods over short time intervals, and can also be used in the day-before scheduling after the unit commitment has been performed. Efficiency is demonstrated by tests on large-scale networks representative of the Italian EHV system View full abstract»

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  • Calculation of self and mutual impedances between sections of transformer windings

    Publication Year: 1989 , Page(s): 308 - 314
    Cited by:  Papers (3)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (564 KB)  

    The author shows how a new frequency-dependent impedance formula, derived on the assumption of a solid homogeneous core, may be adapted to permit calculation of the self and mutual impedances of coil sections on a practical transformer core. Experimental measurements, in comparison with calculated values, show that the effects of the laminations can be accurately simulated by using two distinct resistivities in different parts of the basic formula. A method is given for determining these quantities experimentally. Application of the resulting formula in transient analysis automatically accounts for the effects of transient flux penetration into the transformer core, including the effects of frequency-dependent inductances and transient eddy currents in the core laminations View full abstract»

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  • Improvement of power system stability by crosscoupling generator control systems

    Publication Year: 1989 , Page(s): 289 - 294
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (440 KB)  

    It is proposed that power system stability can be improved by controlling the dynamic response of generators so that they act sympathetically during a transient disturbance. This is shown to be valid theoretically for a simple system consisting of two identical machines fitted with power system stabilisers, the control signals from one machine being used to stabilise the other and vice versa. The extent of the improvements in system response to be expected from such an arrangement in practice is investigated using a dynamic model consisting of two dissimilar machines linked by transmission lines. It is found that the effectiveness of the machine stabilisers is doubled by crosscoupling control signals View full abstract»

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  • Feeder load analysis for utility demand side management

    Publication Year: 1989 , Page(s): 303 - 307
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (392 KB)  

    Today, demand side management is becoming of great interest for electric utilities worldwide, analysis in this field requiring a considerable knowledge of hourly demand information. The authors describe an approach used to analyse the hourly demand of various classes of consumers from remote feeder reading facilities in a regional control centre, which has been developed in conjunction with a research study conducted on consumers of the National Electricity Board (NEB) of Malaysia View full abstract»

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  • General frame of reference for analysis of harmonic distortion in systems with multiple transformer nonlinearities

    Publication Year: 1989 , Page(s): 271 - 278
    Cited by:  Papers (6)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (548 KB)  

    Although the magnetising nonlinearity of power transformers is recognised as a source of harmonic distortion, its effect is often considered negligible, and the analytical models used to assess such effect are extremely simple. A new and more general power system frame of reference which models the coupling between phases and between harmonics is presented. The model is applied to a practical system with several transformers to show that when one or more of these elements operate in the saturation region the voltage harmonic levels can be higher than those permitted by legislation View full abstract»

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