A coupled internal–external flow and conjugate heat transfer simulations and experiments on radiators of a transformer

Paramane, Sachin B.; Veken, Wim Van der; Sharma, Atul

doi:10.1016/j.applthermaleng.2016.04.164

Cited by 39 publications

(17 citation statements)

References 4 publications

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“…For the transformer studied, they found that the horizontal blowing direction had a higher performance due to the lesser air sideway leakages that those of the vertical blowing case. Two years later, in 2016, the same authors carried out the same type of study [21]. However, as a novelty, they provide the effect of the blowing direction on the temperature and velocity distributions of the oil inside the radiators.…”

Section: Radiator Modellingmentioning

confidence: 99%

See 1 more Smart Citation

Thermal Modelling of Electrical Insulation System in Power Transformers

Santisteban¹,

Delgado²,

Ortiz³

et al. 2018

Simulation and Modelling of Electrical Insulation Weaknesses in Electrical Equipment

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Temperature is one of the limiting factors in the application of power transformers. According to IEC 60076-7 standard, a temperature increase of 6 C doubles the insulation ageing rate, reducing the expected lifetime of the device. Power losses of the transformer behave as a heating source, and the insulating liquids act as a coolant circulating through the windings and dissipating heat. For these reasons, thermal modelling becomes an important fact of transformer design, and both manufacturers and utilities consider it. Different techniques for thermal modelling have been developed and used for determining the hot-spot temperature, which is the highest temperature in the winding, and it is related with the degradation rate of the solid insulation. First models were developed as a first estimation for modelling the hot-spot temperature and the top-oil temperature. These models were based on thermal-electric analogy and are known as dynamic models. Other two different kinds of models are widely used for thermal modelling, known as Computational Fluid Dynamics (CFD) and Thermal Hydraulic Network Models (THNMs). These two techniques determine the temperature and velocity fields in the winding and in the insulating fluid. In this chapter, the different techniques for transformer thermal modelling will be introduced and described.

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Section: Radiator Modellingmentioning

confidence: 99%

“…Consequently, from Eqs. (16), (17) and (21), two unknown temperatures and the oil flow can be determined [24].…”

Section: Complete Loop Modellingmentioning

confidence: 99%

Thermal Modelling of Electrical Insulation System in Power Transformers

Santisteban¹,

Delgado²,

Ortiz³

et al. 2018

Simulation and Modelling of Electrical Insulation Weaknesses in Electrical Equipment

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“…Cases regarding optimal design of indoor substation and ventilation are treated in [7,8,9,10,11]. There is even an example where FEM CFD tools were used to gain further insight in conjugate heat transfer for oil inside and air outside the radiators for both ONAN and ONAF transformers [12,13].…”

Section: Introductionmentioning

confidence: 99%

Fem CFD analysis of air flow in kiosk substation with the oil immersed distribution transformer

Stanišić

Jevtić

Das³

et al. 2018

FACTA U EE

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In practice of loading of oil-immersed distribution transformers, there is a need to have lumped thermal model, requiring no big computational resources and computational time. One such model is presented in international transformer loading guide (IEC 60076-7), where heat transfer inside the transformer is modeled. In case of indoor transformer operation, this model does not consider transient thermal phenomena in the room. We developed a lumped model that includes heat transfer in the transformer room. In scope of the research, we also built FEM CFD (finite element method, computational fluid dynamics) model of air flow and heat transfer. The purpose of FEM CFD was to make a better insight into air flow, i.e. to study the simplifications introduced in lumped model and suggest potential improvements. This paper presents results achieved with FEM CFD. The considered case was the transformer with natural oil and natural air flow (ONAN).

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“…The numerical results are confirmed by experimental measurements performed on a five radiator workbench. More recently in [8], 3-D coupled internal oil and external air flow simulations together with a conjugate heat transfer model is used for analyzing the effect of blowing direction on the thermal performance of a five radiators block. In this work it is found that average oil temperature distribution along the height of the panels follows an exponential law instead of the widespread linear one.…”

Section: Introductionmentioning

confidence: 99%

Numerical and experimental thermo-fluid dynamic analysis of a power transformer working in ONAN mode

Rodriguez

Garelli

Storti

et al. 2017

Applied Thermal Engineering

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This paper presents semi-analytical calculations, computational fluid dynamic simulations and experimental measurements accomplished on a typical 30MVA power transformer. An ad-hoc workbench was devised to carry out the experimental measurements. This facility allowed to estimate the values of different key variables involved in heat dissipation within the radiator, like convective heat transfer coefficients, oilflow rate, air-flow speed between radiator fins and overall dissipated heat, among others. The main objectives of the study are to analyze the cooling capacity of the current radiator design working in ONAN mode and to validate the numerical simulation and calculation procedures for further design optimizations. The coupled thermo-hydraulic numerical simulations were performed on a computer cluster due to the high computational cost of the resulting models. The results of the simulations show good agreement with the experimentally measured values and with those obtained with the semianalytical model, thus confirming that this model together with the CFD simulations are an accurate analysis tool. The heat transfer coefficients in the oil, the radiator panel and the air are computed. It is found that convective heat transfer from the panel to the air is approximately 10 times lower than heat transfer in the oil. Possible improvements on the current radiator design are briefly mentioned.

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A coupled internal–external flow and conjugate heat transfer simulations and experiments on radiators of a transformer

Cited by 39 publications

References 4 publications

Thermal Modelling of Electrical Insulation System in Power Transformers

Thermal Modelling of Electrical Insulation System in Power Transformers

Fem CFD analysis of air flow in kiosk substation with the oil immersed distribution transformer

Numerical and experimental thermo-fluid dynamic analysis of a power transformer working in ONAN mode

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