Flow and temperature distributions in a disc type winding-part I: Forced and directed cooling modes

Daghrah, Muhammad; Zhang, Xiang; Wang, Zhongdong; Liu, Qiang; Jarman, Paul; Walker, David T.

doi:10.1016/j.applthermaleng.2019.114653

Cited by 33 publications

(23 citation statements)

References 16 publications

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“…The validity of the CFD modelling tool and methods the authors adopted is proven by flow and temperature measurements of experiment test setups in the authors' previous publications [10,14,18]. The temperature deviations between CFD simulations and experimental test results were within 3 • C [10] with closely matched flow distributions [10,14,18]. Mesh refinement studies were conducted to guarantee mesh independent solutions.…”

Section: Numerical Simulation and Comparisons With Temperature Rise Testsmentioning

confidence: 99%

“…Flow distributions in pump-driven oil directed (OD) cooling modes are quite different from those of thermosiphon-driven oil nature (ON) cooling modes [7]. OD flow distributions feature higher flow rates in the top part of the pass and lower flow rates in the bottom part of the pass [7][8][9][10], whereas ON flow distributions demonstrate the opposite trend [11][12][13][14]. The pitfall of conventional disc-type winding thermal design for OD cooling modes is pumping the oil too hard or having a winding geometry with too high ratio of radial duct height to axial duct width and therefore causing severely uneven flow distribution or even reverse flows at the bottom of the pass [8,10].…”

Section: Introductionmentioning

confidence: 99%

“…OD flow distributions feature higher flow rates in the top part of the pass and lower flow rates in the bottom part of the pass [7][8][9][10], whereas ON flow distributions demonstrate the opposite trend [11][12][13][14]. The pitfall of conventional disc-type winding thermal design for OD cooling modes is pumping the oil too hard or having a winding geometry with too high ratio of radial duct height to axial duct width and therefore causing severely uneven flow distribution or even reverse flows at the bottom of the pass [8,10]. For ON cooling modes, severely uneven flow distributions or even reverse flows at the top part of the pass occur when the total oil flow rate in the winding is relatively low corresponding to the winding power losses [11,12,14,15].…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Comparisons of transformer thermal behaviours between conventional disc type and S disc type windings

Zhang

Liu

Wang

et al. 2021

IET Generation Trans & Dist

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Controlling the highest temperature in the windings is the primary objective of transformer thermal design to guarantee designed transformer thermal life expectancy. Temperature rise test results of a transformer with computational fluid dynamics (CFD) modelling results are compared here to determine typical OD and ON flow rates in the transformer. It then presents CFD studies that compare the thermal behaviour of two types of disc-type windings. The S disc-type winding refers to one that has only axial cooling ducts and physically resembles a layer-type winding. The other type is of conventional disc-type winding. The S disc-type winding shows robust thermal performance due to its quasi-uniform flow distributions in the axial cooling ducts, irrespective of the total oil flow rates or the cooling modes. In contrast, the conventional disc-type windings converted from the S disc-type winding experience uneven flow distributions in the radial cooling ducts that can cause localised overheating. Control of oil flow distribution in conventional disc-type windings is found critical for its thermal design. Heat transfer for the S disc-type winding is further enhanced by axially partitioning the winding into multiple sections, which is optimized based on theoretical analyses and is then verified by CFD modelling.

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Section: Numerical Simulation and Comparisons With Temperature Rise Testsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Comparisons of transformer thermal behaviours between conventional disc type and S disc type windings

Zhang

Liu

Wang

et al. 2021

IET Generation Trans & Dist

Self Cite

View full text Add to dashboard Cite

show abstract

“…Winding temperature rise during transformer operation is one of the important indicators affecting transformer performance [1]. Through calculation analysis and monitoring research, it is found that a large number of transformer operation failures and accidents are caused by the temperature rise problem of the winding hot spot [2][3][4]. The hot spot of the transformer winding is the highest point of the winding temperature when the transformer is running.…”

Section: Introductionsmentioning

confidence: 99%

Analysis of winding temperature field under dynamic variable load of oil-immersed transformer

Yang

et al. 2021

THERM SCI

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The research on the temperature field of the transformer winding under dynamic variable load is of great significance for ensuring the safe operation of power systems. This paper takes an SSP-360000/500 transformer as the research object, establishes a 2-D simulation model, and uses the finite volume method to analyze the high voltage winding and low voltage winding temperature distribution of the transformer under dynamic variable load. The simulation calculation results have been fully verified by the experimental data to make the successful prediction of the overall temperature and hot spot temperature position of forced oil circulation transformers with a guided structure. The results show that the most significant temperature raise occurs at the secondary end of the winding. In the case of dynamic variable load. The temperature raise of the winding becomes larger as the load increases, but before the rated load is in the stable temperature rise range, it can run safely for a long time. However, during overload operation, the average temperature raise of the high voltage winding may exceed its limit, the insulation material is damaged.

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“…Cooling capacity of the current radiator design working in ONAN mode is analyzed and possible improvements on the current radiator design are briefly mentioned. In Daghrah et al., 9 flow and temperature distributions in a disc-type winding are investigated experimentally using particle image velocimetry (PIV) and a temperature measurement system, and are simulated numerically using CFD in forced directed cooling mode. Different liquid inlet velocities, inlet temperatures, and the effect of alternative liquids are also investigated.…”

Section: Introductionmentioning

confidence: 99%

Fans arrangement analysis in oil forced air natural cooling method of power transformer radiator

Taghikhani

Afshar

2020

Proceedings of the Institution of Mechanical Engineers, Part A:

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The cooling of radiators in power transformers employing natural oil-air forced method is the purpose of this study. Two modes used for cooling fans, namely vertical and horizontal placement, will be compared as well. Four sets of radiators have been studied in this research, and in each set, 14 fins and three fans with a diameter of half a meter have been used. The fans will be arranged such that three of them will be placed under the radiator (in vertical position) in the first case, while in the second case, they will be located in one side of the radiator (in horizontal position). The results derived from the comparisons indicate the superiority of the horizontal mode in heat transfer against the vertical mode. Furthermore, it is notable that if the internal fan is disconnected, the cooling can be enhanced with the help of some existing points in the vertical mode. The improvement in heat transfer rate can be observed through locating the vertical fans optimally, once compared to the horizontal placement. The lower reliability of the vertical mode can be detected once the side fans are disconnected, while in any cases, the heat transfer superiority is achievable for horizontal mode. That is because, the disconnection of one of the fans, leads to the negligence of the radiators major parts in the vertical mode.

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Flow and temperature distributions in a disc type winding-part I: Forced and directed cooling modes

Cited by 33 publications

References 16 publications

Comparisons of transformer thermal behaviours between conventional disc type and S disc type windings

Comparisons of transformer thermal behaviours between conventional disc type and S disc type windings

Analysis of winding temperature field under dynamic variable load of oil-immersed transformer

Fans arrangement analysis in oil forced air natural cooling method of power transformer radiator

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