Analysis of Aged Oil on the Cooling of Power Transformers from Computational Fluid Dynamics and Experimental Measurements

Kassi, K. S.; Farinas, Marie-Isabelle; Fofana, I.; Volat, Christophe

doi:10.36884/jafm.9.si2.25830

Cited by 4 publications

(2 citation statements)

References 8 publications

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“…It is noted that acidity varies due to hydrolysis whereas the viscosity varies with respect to oxidation in the natural ester. Perrier et al [49] and [50] used kinematic viscosity to study the heat transfer of mixed dielectrics. Also, while investigating viscosity, DGA, and ageing performance of vegetal oil compared to mineral oil, [51] found that natural esters have 42.86% more lifetime than mineral oil when used in distribution transformers.…”

Section: Viscositymentioning

confidence: 99%

Alternative liquid dielectrics in power transformer insulation: a review

Tlhabologo

Samikannu

Mosalaosi

2021

IJEECS

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Transformer liquid dielectrics evolved where mineral oil has been the dominant choice until emergence of synthetic esters and natural esters. Natural ester-based oils have been under extensive investigations to enhance their properties for replacing petroleum-based mineral oil, which is non-biodegradable and has poor dielectric properties. This paper focuses on exposition of natural ester oil application in mixed transformer liquid dielectrics. Physical, chemical, electrical, and ageing characteristics of these dielectrics and the dissolved gas analysis (DGA) were reviewed. Physical properties include viscosity, pour point, flash and fire point which are vital indicators of heat insulation and fire risk. Chemical properties considered are water content, acid number, DGA, corrosive sulphur, and sludge content to limit and detect degradation and corrosion due to oil ageing. Electrical properties including breakdown voltage were considered for consistent insulation during overload and fault conditions. These properties of evolving alternative dielectrics were reviewed based on ASTM International standards and International Electro technical Commission standards for acceptable transformer liquid dielectrics. This review paper was compiled to avail modern methodologies for both the industry and scholars, also providing the significance of using mixed dielectrics for power transformers as they are concluded to show superiority over non-mixed dielectrics.

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Section: Viscositymentioning

confidence: 99%

Alternative liquid dielectrics in power transformer insulation: a review

Tlhabologo

Samikannu

Mosalaosi

2021

IJEECS

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“…All of these losses produce heat, which must be transferred away to the external environment without causing the core, winding, or structural components to become too hot, which could damage the insulation. It is well known that the oil's contact with the coils and magnetic core causes the transfer of heat from those to the latter, where the other components of the cooling system discharge heat to the external environment through conduction, convection, and radiation [5,6].…”

Section: Introductionmentioning

confidence: 99%

Thermal Conductivity Modeling of Dielectric Oils-Based Nanofluids Using the Finite Element Method

Boukounacha,

Zegnini,

Yousfi

et al. 2024

aeletters

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The enhancement of the thermal conductivity of dielectric oils has a positive effect on the performance of electrical equipment that uses these oils as a cooling medium. Nanofluids (NFs) have inspired high-voltage engineers to use them as alternative fluids in power transformers due to their impressive heat transfer and insulation compared to traditional dielectric oils. The present study is a numerical simulation by COMSOL Multiphysics of the thermal conductivity of NFs based on dielectric oils used in power transformers, to identify the effect of temperature, the concentration of nanoparticles (NPs), type of insulating fluid and NPs on thermal conductivity. The NFs were modeled inside a cube using the finite element method (FEM) by applying a temperature gradient. Several types of NPs were used (SiC, ZnO, TiO2, and Al2O3) in addition to several volume concentrations (0%, 0.001%, 0.002%, 0.01%, and 0.02%). The results showed a significant improvement in the thermal conductivity of the NFs with increasing concentration since the best results were recorded at an estimated volume concentration of 0.02%, while the lowest results were obtained for samples using a volume concentration estimated at 0.001%. The base fluid (BF) type and NPs play a dominant role in the thermal performance of the NFs, as the vegetable oil-based nanofluid provided the highest thermal conductivity values and silicon carbides (SiC) was the best NPs used in this study. However, a decrease in thermal transfer capacities was observed for all samples with increasing temperature.

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Numerical and Experimental Analysis of the Aging Impact on the Cooling Capacity of a Natural Ester-Based Oil Used in Power Transformers

Ortiz

Alfredo

Delgado

et al. 2018

2018 IEEE International Conference on High Voltage Engineering and Application (ICHVE)

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An experimental and numerical research was conducted to study the aging effect on the cooling performance of a natural ester-based oil habitually used in power transformers. A monitored experimental platform has been used to observe the temperature increases with the aging of the insulation system (oil and paper). Three samples with three aging levels were tested at three load levels: underload, rated and overload regimes. The two aged samples (6 liters each) were aged in an accelerated way within an oven: 1 week at 150 ºC. Also, some physicochemical properties of the insulation system (paper and oil) were determined. A 2D numerical model has been developed with COMSOL Multiphysics to determine the temperature and velocity distributions of the different samples in the platform to analyze their differences and to compare their cooling capacity. At first sight, the aging affects negatively to the cooling capacity of the new alternative liquid based on natural esters. I.

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Analysis of Aged Oil on the Cooling of Power Transformers from Computational Fluid Dynamics and Experimental Measurements

Cited by 4 publications

References 8 publications

Alternative liquid dielectrics in power transformer insulation: a review

Alternative liquid dielectrics in power transformer insulation: a review

Thermal Conductivity Modeling of Dielectric Oils-Based Nanofluids Using the Finite Element Method

Numerical and Experimental Analysis of the Aging Impact on the Cooling Capacity of a Natural Ester-Based Oil Used in Power Transformers

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