Numerical Study of Cooling Solutions Inside a Power Transformer

Chereches, Monica; Miron, Livia; Hudișteanu, Sebastian Valeriu

doi:10.1016/j.egypro.2017.03.1103

Cited by 23 publications

(9 citation statements)

References 12 publications

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“…Primary resistance (Ω) X 21 Secondary resistance (Ω) X 22 Applied test voltage (kV) X 23 Primary winding losses (W) X 24 Secondary winding losses (W) X 25 Core losses (W) X 26 Environment temperature ( o C) Y 1…”

Section: Discussionmentioning

confidence: 99%

Hot-Spot Temperature Forecasting of the Instrument Transformer Using an Artificial Neural Network

Juarez-Balderas¹,

Medina-Marín

Olivares-Galván

et al. 2020

IEEE Access

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Cast resin medium voltage instrument transformer are highly used because of several benefits over other type of transformers. Nevertheless, the high operating temperatures affects their performance and durability. It is important to forecast the hot spots in the transformer. The aim of this study is to develop a model based on Artificial Neural Networks (ANN) theory to be able to forecast the temperature in seven points, taking into account twenty-six input data of transformer design features. 792 simulations were carried out in COMSOL Multiphysics®to emulate the heat transfer in the transformer. The data obtained were used to train 1110 ANN with different number of neurons and hidden layers. The ANN with the best performance (R = 1, MSE=0.003455) has three hidden layers with 10, 9 and 9 neurons respectively. The ANN predictions were validated with finite element simulations and laboratory thermal tests which present similar patterns. With this accuracy in the prediction of hot-spot temperature, this ANN can be used to optimize the design of instrument transformers. INDEX TERMS Artificial neural networks, resin-cast instrument transformer, epoxy resins, finite element analysis, hot-spot temperature

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Section: Discussionmentioning

confidence: 99%

Hot-Spot Temperature Forecasting of the Instrument Transformer Using an Artificial Neural Network

Juarez-Balderas¹,

Medina-Marín

Olivares-Galván

et al. 2020

IEEE Access

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“…A conjugate heat transfer (CHT) was applied to solve strong coupling between heat transfer and fluid dynamic problems. This approach was also performed by Chereches et al, [17]. Finite element method-based COMSOL Multiphysics software was adopted to solve Navier-Stokes equations for weakly compressible fluid, continuity equation and energy equation.…”

Section: Governing Equationmentioning

confidence: 99%

“…, where g is the gravitational acceleration (m s -2 ) and ρ ref is the reference oil density at the initial temperature of the system. In Chereches et al, [17]'s previous works, the flow condition was characterized by three dimensionless parameters as the following…”

Section: Governing Equationmentioning

confidence: 99%

Numerical Modelling for Natural Oil Convection of Non-Guided Winding Cooling Arrangement

Ibrahim

Kadir

Azis

et al. 2020

CFDL

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The hot-spot temperature is a key parameter in transformer loading management. It plays a significant role in evaluating transformer winding thermal performances, as well as in the determination of winding insulation's loss of life. A simplified winding thermal model has been developed based on the presented methodology in favour to reduce real-world model complexity. A conjugate heat transfer has been approached to solve the cooling effects of natural oil convection. Results show a good agreement with only 3.1% percentage difference for the average winding temperature between the newly developed winding model and manufacturer factory-end test report. The plotted graphs of oil flow and thermal distributions showed a unique relation between localised hot-spot temperature and oil flow patterns. The hottest temperature and its location are well pronounced with the inclusion of eddy current loss distribution within winding height. The proposed methodology can be used to investigate the oil cooling scheme of transformer winding and allows the manufacturers to optimise their thermal design.

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“…The literature presents some papers dedicated to simulating a power transformer using a finite element method (FEM) considering the model-based in the thermal properties [5][6][7][8][9][10] and electromagnetic phenomena [11][12][13][14][15]. Some other papers also inves-tigate coupled thermal electromagnetic modeling of the equipment [16,17]; however, the literature is still limited.…”

Section: Introductionmentioning

confidence: 99%

Coupled Electromagnetic-Thermal Simulation of a Power Transformer by 3d Fem

Henriques

Vizeu²,

Souza³

et al. 2020

Acta Polytech

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Power transformers are the most common equipment in an electric power system, which has been manufactured in the last decade. However, overheating can damage them, considerably reducing their operation lives, which may cause economic losses to the power utilities. The motivation of this paper is to investigate the time and power overload limits that a power transformer can be subjected to and how it will impact its temperature. Investments in the grid can be delayed if a transformer can support some overload during some momentary load demand increase. In this context, this paper presents a study of a 30/40MVA power transformer by 3D finite element method (FEM) for coupled thermal-electromagnetic simulations to investigate its thermal behaviour when it is submitted to its nominal load at a steady-state operation and a variable load during a period of one day. The simulations were performed with the commercial software packages Flux 3D and AcuSolve, for electromagnetic and thermal modelling, respectively. The modelled equipment was based on a power transformer installed in the Light Serviços de Eletricidade S.A, the utility that supplies electrical energy to the city of Rio de Janeiro, in Brazil. Since the literature doesn’t present many works simulating coupled thermal-electromagnetic power transformers in 3D-FEM, this paper has the goal to bring new contributions to this field. Three study cases were modelled, and some simplifications in transformer’s geometry were made in some of them to reduce the computation time usually required for such a simulation. The obtained results are presented and compared with the measured values for the temperature in the hot spot of the transformer and in the top of the oil, to investigate the impact of these simplifications in the calculated results.

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Numerical Study of Cooling Solutions Inside a Power Transformer

Cited by 23 publications

References 12 publications

Hot-Spot Temperature Forecasting of the Instrument Transformer Using an Artificial Neural Network

Hot-Spot Temperature Forecasting of the Instrument Transformer Using an Artificial Neural Network

Numerical Modelling for Natural Oil Convection of Non-Guided Winding Cooling Arrangement

Coupled Electromagnetic-Thermal Simulation of a Power Transformer by 3d Fem

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