Thermal-hydraulic model for temperature prediction on oil-directed power transformers

• Published in: International journal of electrical power & energy systems Vol. 151; p. 109133
• Main Authors: Oliveira, M.M., Medeiros, L.H., Kaminski, A.M., Falcão, C.E.G., Beltrame, R.C., Bender, V.C., Marchesan, T.B., Marin, M.A.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.09.2023
• Subjects: Oil-directed transformer; Power transformers; Temperature rise test; Thermal performance; Thermal-hydraulic model; Temperature rise test; Oil-directed transformer; Power transformers; Thermal-hydraulic model; Thermal performance
• ISSN: 0142-0615; 1879-3517
• DOI: 10.1016/j.ijepes.2023.109133

The temperatures of a power transformer have direct influence on the windings insulation deterioration, determining how long the equipment will be able to remain in operation. In order to better predict and study the transformer thermal behavior, a thermal-hydraulic model (TH) for oil-directed (OD) power transformer is proposed. From the constructive dimensions and the operative characteristics of the transformer, the proposed model is able to determine the complete oil flow and temperature distributions over the magnetic core, windings and radiators by iteratively solving an algorithm composed of both hydraulic and thermal resistance networks. A transformer prototype was assembled and equipped with 29 optical fiber sensors as part of a measurement system in order to validate the approach. The details of the active part, tank and radiators modelings are presented in a generalized way, being applicable to different constructive arrangements. The validation results show a maximum relative error of 1.31% for temperature, accurately describing the flow and temperature fields of the prototype, indicating that the model can be satisfactorily used for predicting the hydraulic and thermal behaviors of electric transformers. •Winding convergence through finite volume and thermal-hydraulic coupling.•Thermal radiation modeled for external heat transfer on tank and radiators.•Temperature distribution along winding turns, insulation paper and oil channels.•Prototype equipped with 29 optical fiber sensors for model validation.•TH model validation presenting 1.31% of maximum relative error.