Fast 3-dimensional interactive computation of stray field and losses in asymmetric transformers

Koppikar, D.A.; Kulkarni, Vikas; Turowski, J.

doi:10.1049/ip-gtd:20000435

Cited by 12 publications

(2 citation statements)

References 3 publications

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“…Sometimes it has no influence but generally it plays a decisive role at reducing or increasing power losses. Thus, from Maxwell's equations describing processes inside the solid metal and the solution for sinusoidal performance of their Helmholtz equation (Koppikar et al, 2000), the envelope of maximum electromagnetic field H m changes with penetration depth in direction of the propagation z of electromagnetic fields H m and E m from surface following the law: COMPEL 31,2…”

Section: Electromagnetic Analytical Approachmentioning

confidence: 99%

3D heating hazard assessment on transformer covers. Arrangement decisions

Penabad‐Duran

López‐Fernández

Turowski

et al. 2012

COMPEL

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Purpose -The purpose of this paper is to apply a 3D methodology to assess the heating hazard on transformer covers and present a practical tool to design amagnetic inserts arrangement. Design/methodology/approach -A practical 3D methodology linking an electromagnetic analytical formulation with thermal finite element method is used for computation. Such methodology allows the evaluation of the temperature on metallic device elements heated by electromagnetic induction. This is a 3D problem which in the case of power transformers becomes especially difficult to apply due to the discretization requirement into the thin skin depth penetration compared to big machine dimensions. Findings -From the numerical solution of the temperature field, decisions on dimensions and different amagnetic inserts arrangements can be taken to avoid hot spots on transformer covers. Research limitations/implications -Some parameters presented in the model as heat exchange coefficients and material properties are difficult to determine from formulae or from the literature. The accuracy of the results strongly depends on the proper identification of those parameters, which the authors adjust based on measurements. Originality/value -Differing from previous works found in the literature, which focus their results in power loss computation methods, this paper evaluates losses in terms of temperature distribution, which is easier to measure and validate over transformer covers. Moreover, an experimental work is presented where the temperature distribution is measured over a steel cover plate and a cover plate with amagnetic insert.

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Section: Electromagnetic Analytical Approachmentioning

confidence: 99%

3D heating hazard assessment on transformer covers. Arrangement decisions

Penabad‐Duran

López‐Fernández

Turowski

et al. 2012

COMPEL

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“…Calculating stray losses requires an understanding of the stray magnetic field. To address this problem, efficient methods have emerged to quickly and approximately estimate the equivalent leakage reluctance, in particular by using the Reluctance Network Modelling (RNM) method [12,13]. The adoption of numerical methods, such as the Finite Element Method (FEM), has greatly facilitated the evaluation of the stray magnetic field and its associated additional losses.…”

Section: Introductionmentioning

confidence: 99%

Analysing and Computing the Impact of Geometric Asymmetric Coils on Transformer Stray Losses

Hernandez-Robles,

Gonzalez-Ramirez,

Olivares-Galvan

et al. 2024

ASI

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Designing and manufacturing transformers often involves variations in heights and thicknesses of windings. However, such geometric asymmetry introduces a significant impact on the magnitude of stray transformer losses. This study examines the effects of asymmetric coils on the generation of stray losses within core clamps and transformer tank walls. A model has been introduced to ascertain the dispersion magnetic field’s value at a specific distance from the coil. The analysis extends to characterising the dispersion magnetic field reaching the tank walls by using electromagnetic simulation by a finite element method. It explores strategies to diminish stray losses, including the placement of magnetic shunts as protective shields for the tank walls. It delves into the efficacy of employing a transformer shell-type configuration to mitigate the magnetic dispersion field. The findings revealed that achieving greater symmetry in transformer coils can minimise stray losses. Specifically, the incorporation of magnetic shunts has the potential to reduce additional losses by 40%, while the adoption of a shell-type configuration alone can lead to a 14% reduction. This work provides valuable insights into optimising transformer designs, contributes a user-friendly tool for estimating additional tank losses, thereby enhancing the knowledge base for transformer manufacturers.

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