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1

A general transfer function representation for a class of hyperbolic distributed parameter systems

Bartecki K.

International Journal of Applied Mathematics and Computer Science

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2013

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Vol. 23, no. 2

291--307

EN

Results of transfer function analysis for a class of distributed parameter systems described by dissipative hyperbolic partial differential equations defined on a one-dimensional spatial domain are presented. For the case of two boundary inputs, the closed-form expressions for the individual elements of the 2×2 transfer function matrix are derived both in the exponential and in the hyperbolic form, based on the decoupled canonical representation of the system. Some important properties of the transfer functions considered are pointed out based on the existing results of semigroup theory. The influence of the location of the boundary inputs on the transfer function representation is demonstrated. The pole-zero as well as frequency response analyses are also performed. The discussion is illustrated with a practical example of a shell and tube heat exchanger operating in parallel- and countercurrent-flow modes.

2

Fault diagnosis of actual large-power high-voltage windings using transfer function method

Rahimpour E., Tenbohlen S.

Archives of Electrical Engineering

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2011

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Vol. 60, nr 3

269-281

EN

The transfer function (TF) method is presently a well-known method used to detect various types of winding damage in power transformers. Although abundant research has been done on this subject using laboratory windings as test objects, it is hard to find one, whose test objects are actual large-power transformer windings. Hence, a 400 kV disc winding consisting of 86 discs is used in this paper to study turn-to-turn short circuit with the help of the TF method. To evaluate the effects of this type of fault on TF curves, some mathematical comparison algorithms are used in this research.

3

Experimental and theoretical determination of transfer function of transformer windings

Florkowski Marek, Furgał Jakub

Archives of Electrical Engineering

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2003

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Vol. 52, nr 2

137--151

EN

A method based on the transfer function has been used more and more frequently for investigation of transformer windings. It is applied more and more widely as a maintenance procedure lor the identification of damage and deformation of transformer windings as well as it might be used to estimate the condition of an insulating system. The method can also he used to detect possible manufacturing damages or to check minor dislocations of the windings. It is based on the comparison of current measurements of the transfer function with reference measurements. The application of this method in the investigation ol transformers is determined by an exact measurement of the transfer function by experiment and by mathematical modelling. Both methods of determining the transfer function of the transformer are being refined and developed. Transfer function measurement, analysis and evaluation methods are presented in this paper. Described methods were applied for measuring and calculating of the transfer function for two of transformer windings.

PL

Uzwojenia transformatorów są badane coraz częściej przy zastosowaniu metody, której podstawą jest funkcja przenoszenia. Jest ona wykorzystywana do wykrywania uszkodzeń oraz zniekształceń uzwojeń. Może być także stosowana do oceny stanu układu izolacyjnego oraz do kontroli procesu produkcyjnego lub do wykrywania przemieszczeń uzwojeń. Metoda polega na porównaniu wyniku pomiaru funkcji przenoszenia z pomiarami odniesienia. Zastosowanie tej metody w badaniach transformatorów jest zależne od dokładnych pomiarów lub modelowania matematycznego funkcji przenoszenia. Obie metody wyznaczania funkcji przenoszenia są obecnie rozwijane i doskonalone. W artykule przedstawiono pomiary funkcji przenoszenia, analizę i rozwój metod. Porównano wyniki pomiarów i obliczeń funkcji przenoszenia dwu różnych uzwojeń transformatora.