Flux distribution in single phase, Si–Fe, wound transformer cores

Loizos, George; Kefalas, Themistoklis D.; Kladas, Antonios G.; Souflaris, Thanassis; Paparigas, D.G.

doi:10.1016/j.jmmm.2008.04.068

Cited by 16 publications

(13 citation statements)

References 11 publications

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“…No-load current and voltage are captured using a current probe based on the Hall effect, an active high-voltage differential probe, and a National Instruments NI6143 data acquisition card. Analysis of the captured data was carried out using LabVIEW software, Loizos [11], Loizos [12]. Table I summarises the computed and measured no-load loss of the tested wound core for different working induction ratings.…”

Section: Arwtr2010mentioning

confidence: 99%

Advanced computational tools for wound core distribution transformer no‐load analysis

Kefalas

Kladas

2012

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

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The paper deals with the accurate representation of laminated wound cores with a low computational cost using 2D and 3D finite element (FE) method. An inverse anisotropy model is developed in order to model laminated wound cores. The inverse anisotropy model was integrated to the 2D and 3D FE method. A comparison between 2D and 3D FE techniques was carried out. FE techniques were validated by experimental analysis. In the case of no-load operation of wound core transformers both 2D and 3D FE techniques yields the same results. Computed and experimental no-load losses agree within 2% to 6%. The originality of the paper consists in the development of an inverse anisotropy model, specifically formulated for laminated wound cores, and in the effective representation of electrical steels using a composite single-valued function. By using the aforementioned techniques the FE computational cost is minimised, the numerical stability and convergence of the Newton-Raphson iterative method are improved, and the 3D FE analysis of wound cores is rendered practical.

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Section: Arwtr2010mentioning

confidence: 99%

Advanced computational tools for wound core distribution transformer no‐load analysis

Kefalas

Kladas

2012

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

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“…However, the magnetic flux density by using FEM was not adequately validated. For example, convex distributions have been observed by some researchers [4,5], while other researchers found it to be concave, even where experiments have extremely similar configurations [11][12][13]. Therefore, a more reliable approach is needed to provide a clearer understanding of the internal magnetic field within transformers.…”

Section: Introductionmentioning

confidence: 99%

Distributed Magnetic Flux Density on the Cross-Section of a Transformer Core

Pan

et al. 2019

Electronics

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In this paper, the magnetic flux density distribution on the cross-sections of a transformer core is studied. The core for this study consists of two identical U-shaped cores joint at their open surfaces with known air gaps. The magnetic flux density at one of their joint boundary surfaces was measured for different air gaps. A finite element model (FEM) was built to simulate the magnetic flux density and compared with experiment data. Using the validated FEM, the distributed magnetic flux density on the cross-section of the core structure can be obtained when the air gap approaches zero. An engineering model of the density based on the Ampere’s circuit law was also developed and used to explain the relationship between air gap and mean magnetic flux density on the cross-section. The magnetic flux density on the cross-section was found to have a convex-shaped distribution and could be described by an empirical formula. Using this approach, the magnetic flux density distribution in cores with different interlayer insulation was obtained and discussed. This method could also examine the leakage of magnetic flux density in the air gap region when the distance is non-zero, and the relationship between the leakage field and the field in the core structure. The proposed method and model can provide a more detailed understanding for the magnetic field of transformer cores and potential application in designing quiet transformers and condition monitoring.

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“…The performance of a transformer core depends directly on the core's materials and construction . When laminated transformer cores (which can be stacked in any alphabetical order, such as E‐I, C‐I, or U‐T, and can be ordered using 2 stacked pieces) are manufactured, core sheets are drilled in certain regions.…”

Section: Introductionmentioning

confidence: 99%

“…These holes are necessary for tailoring transformer‐core designs, even though the holes deteriorate the cores' magnetic properties. However, although various studies investigated core manufacturing, proper hole positions and the impacts of holes on transformer designs in stacked transformer cores were still remained uncertain. To fill this research gap, spark erosion was used to pierce laminated transformer‐core sheet specimens and form circles with various diameters at certain locations on the sheets.…”

Section: Introductionmentioning

confidence: 99%

Numerical and experimental analyses of the deterioration in magnetic flux density distribution on perforated transformer core steels

Güneş

2018

Int J Numerical Modelling

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The holes in transformer core sheets are necessary for tailoring transformer‐core designs even though they cause more or less deterioration in the magnetic properties. With using spark erosion, specimens were pierced as a circle shape at certain locations and diameters to compare their effects to the magnetic properties by means of hysteresis curves, Magneto‐optical Kerr imaging, and finite element method. It was found that piercing the middles and corners of sheets at regular intervals dropped the sheets' relative permeabilities to ranges of 28% to 70%. Additionally, significant increments in power losses, from 0.8 to 2.54 W/kg at 50 Hz, depending on increases in hole diameters, were noted. These effects did not occur in a non‐pierced sample. Furthermore, considering all possible scenarios based on hole diameters and locations, laminated transformer‐core sheets were simulated to study distributions of flux lines, flux densities, and magnetic forces using 2‐dimensional static magnetic analyses. Holes in the sheets and the holes' proximities to each other were noted using magneto‐optical Kerr microscopies. Kerr images and diagrams of flux propagation from the simulation were individually compared to consider how the sheets flux distributions were influenced by varying the physical properties of the holes. The cases' effects on basic transformer cores were also investigated using 2‐dimensional static analyses.

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Flux distribution in single phase, Si–Fe, wound transformer cores

Cited by 16 publications

References 11 publications

Advanced computational tools for wound core distribution transformer no‐load analysis

Advanced computational tools for wound core distribution transformer no‐load analysis

Distributed Magnetic Flux Density on the Cross-Section of a Transformer Core

Numerical and experimental analyses of the deterioration in magnetic flux density distribution on perforated transformer core steels

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