Abstract
Transformer thermal behavior determines the insulation ageing rate and therefor the transformer thermal life expectancy. Controlling the highest temperature in windings is the primary objective of transformer thermal design. This paper
compares temperature rise tests results of a transformer with computational fluid dynamics (CFD) modelling results to determine typical OD and ON flow rates in the transformer. It then presents CFD studies that compare the thermal behavior of two types of disc-type windings. One has only axial cooling ducts
and physically resembles a layer-type winding, referred to as S disc-type winding. The other type is of conventional disc-type winding converted from the S disc-type winding. The S disc-type winding shows robust thermal performance due to its quasiuniform flow distributions in the axial cooling ducts, irrespective
of the total oil flow rates or the cooling modes. In contrast, the converted conventional disc-type windings experience uneven flow distributions in the radial cooling ducts under certain operating conditions that can cause localized 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 can be further enhanced by axially partitioning the winding into multiple sections, which is proposed, optimized based on theoretical analyses and is then
verified by CFD modelling in this paper.
compares temperature rise tests results of a transformer with computational fluid dynamics (CFD) modelling results to determine typical OD and ON flow rates in the transformer. It then presents CFD studies that compare the thermal behavior of two types of disc-type windings. One has only axial cooling ducts
and physically resembles a layer-type winding, referred to as S disc-type winding. The other type is of conventional disc-type winding converted from the S disc-type winding. The S disc-type winding shows robust thermal performance due to its quasiuniform flow distributions in the axial cooling ducts, irrespective
of the total oil flow rates or the cooling modes. In contrast, the converted conventional disc-type windings experience uneven flow distributions in the radial cooling ducts under certain operating conditions that can cause localized 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 can be further enhanced by axially partitioning the winding into multiple sections, which is proposed, optimized based on theoretical analyses and is then
verified by CFD modelling in this paper.
Original language | English |
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Journal | IET Generation, Transmission and Distribution |
Publication status | Accepted/In press - 22 Sept 2021 |