3D finite element computation of the high frequency parameters of power transformer windings

Azzouz, Zin-Eddine; Foggia, Albert; Pierrat, L.; Meunier, G.

doi:10.1109/20.250666

Cited by 24 publications

(9 citation statements)

References 7 publications

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“…From and , a nodal system can be defined to describe the winding (Fig. 10) (13) where and correspond to the vectors of nodal voltages and currents; and is the nodal admittance matrix which, for a lossless system, is defined as follows [2]: (14) where is the nodal matrix of inverse inductances, computed from and the incidence matrix (since is a branch matrix) …”

Section: Appendixmentioning

confidence: 99%

“…One can appreciate that the core window shapes the distribution of the magnetic flux, affecting the values of self and mutual inductances. The most accurate way to take this into account when using computer methods is the application of electromagnetic-field simulations, which are able to consider the transformer geometry in great detail [9], [13]. Among the several numerical methods available for this purpose, the most commonly used approach is FEM analysis, which has proven to be very accurate.…”

Section: Introductionmentioning

confidence: 99%

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Accurate and Efficient Computation of the Inductance Matrix of Transformer Windings for the Simulation of Very Fast Transients

Gómez

León

2011

IEEE Trans. Power Delivery

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When a transformer is subjected to very fast front transients, the penetration of the magnetic flux into the core becomes, in general, negligible. To represent this phenomenon, it is common practice to compute the winding inductance matrix (turn-to-turn) at very high frequencies using the expressions for air-core inductors. However, since the core becomes a magnetic insulating wall at very high frequencies (MHz), the distribution of the magnetic field is altered because the field cannot enter the region occupied by the core. Therefore, the air-core approximation formulae overestimate the inductance at high frequencies. This is especially true in the region inside the core window. Large errors are found when the inductances are computed with the air-core approximation. This paper presents a technique, based on the application of a multilayer method of images, to take the presence of the core into consideration. The final expressions are very simple, yet they give remarkably accurate results. Comparisons with finite-element analyses prove the excellent accuracy of the technique.Index Terms-Inductance matrix, magnetic fields, method of images, transformer windings, very fast transients.

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Section: Appendixmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Accurate and Efficient Computation of the Inductance Matrix of Transformer Windings for the Simulation of Very Fast Transients

Gómez

León

2011

IEEE Trans. Power Delivery

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“…Till now, calculation of lumped parameters of power transformers by means of FEM was accomplished [16][17][18][19][20]. In this paper, the transient behavior of dry-type transformers by using powerful and accurate method of FEM has been investigated.…”

Section: Introductionmentioning

confidence: 99%

Transient simulation of cast-resin dry-type transformers using FEM

Vahdi

Eslamian

Hosseinian

2010

Euro. Trans. Electr. Power

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SUMMARYNon-flammable characteristic of cast-resin dry-type transformers make them suitable for different kind of usages. This paper presents a method of how to obtain high frequency model of these transformers. For this purpose a detailed model is used and parameters of the model including resistances, inductances, and capacitances are calculated using finite element method (FEM). In order to validate the model, a set-up was constructed for testing on high voltage winding of dry-type transformer. The simulation results were compared with the experimental data measured from frequency response analysis (FRA) and impulse tests.

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“…The FEM analysis is an accurate method for calculation of inductance which is able to consider the details of the transformer geometry (Azzouz et al, 1993). However, this method is computationally expensive.…”

Section: Introductionmentioning

confidence: 99%

Computation of the inductance matrix of axisymmetric windings for very fast transients studies in transformers

Eslamian

Vahidi

2014

COMPEL: The International Journal for Computation and Mathematics in Electrical and Electronic Engineering

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Purpose -To study very fast transients in transformers, it is required to compute the inductance matrix of windings at very high frequencies (MHz). The core acts as a flux barrier at very high frequencies, affecting the values of the self and mutual inductances of windings. In the previous work by the authors, analytical methods for computation of the inductance matrix at very high frequencies, using a 2-D planar approximation of the transformer geometry, were presented. The purpose of this paper is to present analytical methods for the same problem in cylindrical coordinates which do not suffer from the previous approximations in geometry. Design/methodology/approach -A method based on the Fourier integral transform is described for the calculation of inductance outside the core window. For the region inside the core window, inductance formulas are extracted using the Fourier series analysis. Findings -The final expressions are accurate and fast convergent. Comparisons with FEM simulations and previous 2-D planar formula prove the excellent accuracy of the proposed inductance formulas. Originality/value -The value of the presented formulas accounts for considering the effect of iron core on inductances in transformer very fast transient analysis.

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3D finite element computation of the high frequency parameters of power transformer windings

Cited by 24 publications

References 7 publications

Accurate and Efficient Computation of the Inductance Matrix of Transformer Windings for the Simulation of Very Fast Transients

Accurate and Efficient Computation of the Inductance Matrix of Transformer Windings for the Simulation of Very Fast Transients

Transient simulation of cast-resin dry-type transformers using FEM

Computation of the inductance matrix of axisymmetric windings for very fast transients studies in transformers

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