Comparison of Electrical Parameters of Oil-Immersed and Dry-Type Transformer Using Finite Element Method

Authors: U. Amin, A. Talib, S. A. Qureshi, M. J. Hossain, G. Ahmad

Abstract:

The choice evaluation between oil-immersed and dry-type transformers is often controlled by cost, location, and application. This paper compares the electrical performance of liquid- filled and dry-type transformers, which will assist the customer to choose the right and efficient ones for particular applications. An accurate assessment of the time-average flux density, electric field intensity and voltage distribution in an oil-insulated and a dry-type transformer have been computed and investigated. The detailed transformer modeling and analysis has been carried out to determine electrical parameter distributions. The models of oil-immersed and dry-type transformers are developed and solved by using the finite element method (FEM) to compare the electrical parameters. The effects of non-uniform and non-coherent voltage gradient, flux density and electric field distribution on the power losses and insulation properties of transformers are studied in detail. The results show that, for the same voltage and kilo-volt-ampere (kVA) rating, oil-immersed transformers have better insulation properties and less hysteresis losses than the dry-type.

Keywords: Finite element method, flux density, transformer, voltage gradient.

Digital Object Identifier (DOI): doi.org/10.5281/zenodo.1316432

References:

[1] T. Nunn, “A comparison of liquid-filled and dry-type transformer technologies”, IEEE IAS/PCA Cement Industry Technical Conference, pp. 105-112, 2000.
[2] John J. Winders, “Power Transformers Principles and Applications”, Marker Dekker, Inc. New York, 2002.
[3] E. Rahimpour, D. Azizian, “Analysis of temperature distribution in cast-resin dry-type transformers,” Electrical Engineering, vol. 89, pp. 301-309, April 2006.
[4] P. K. Dooley, “A comparison of liquid-filled and dry-type transformers for industrial applications”, Pulp and Paper Industry Technical Conference, 16-20 June, 1997.
[5] Cooper Power Systems, “Application for LEED Innovation & Design Points, Transformer Technology: Liquid-filled vs. Dry-type”, Bulletin B210-05059, Revision 1, February 2008.
[6] Jehan Shazly, Amr A. Adly, “Extension to the finite element technique for the magneto-thermal analysis of aged oil cooled-insulated power transformers”, pp. 167-176, April 2012.
[7] Marina A. Tsili, Eleftherios I. Amoiralis, Anthonios G. Kladas and Athanassios T. Souflairis, “Power transformer thermal analysis by using an advanced coupled heat transfer and fluid flow FEM model”, International Journal of Thermal Sciences, vol. 53, pp. 188-201, 2012.
[8] Hua-Shu Liu, Lin Ma, Yuan-Tong Gu, Shawn Nielsen, “Numerical investigation of mechanical and thermal dynamic properties of the industrial transformer”, International Journal of Computational Methods (IJCM), vol. 11, 2004.
[9] Magdy B. Eteiba, Essam A. Alzahab and Yomna O. Shaker, “Steady State Temperature Distribution of Cast Resin Dry-type Transformer Based on New Thermal Model Using Finite Element Method”, International Journal of Electrical, Computer, Energetic, Electronic and Communication Engineering, vol. 4, pp. 361-365, 2010.
[10] B. Vahdi, M. Eslamian and S. H. Hosseinian, “Transient simulation of cast-resin dry-type transformers using FEM”, European Transactions on Electrical Power, vol. 21, pp. 363-379, 2011.
[11] M. Florkowski, B. Florkowska, J. Furgal, P. Pajctk, “The impact of oil and temperature on initial voltage distributions in transformer windings at ultra-fast stresses”, Annual Report Conference on Electrical Insulation and Dielectric Phenomena, 2010.
[12] M. M. Isa, M. Z. A. A. Kadir, C. Gomes, N. Azis, M. Izadi, O. S. H. Alyozbaky, “Analysis on Magnetic Flux Density and Core Loss for Hexagonal and Butt-lap Core Joint Transformers”, Annual IEEE Southern Power Electronics Conference (SPEC), 5-8 December, 2016.
[13] Christian Freitag, Thomas Leibfried, “Mixed Core Design for Power Transformers to Reduce Core Losses”, International Conference on Optimization of Electrical and Electronic Equipment (OPTIM), 25-27 May, 2017.
[14] https://wwwasw.comsol.com/multiphysics/finite-element-method
[15] Kirschen, Daniel, Fundamentals of Power System Economics, John Wiley & Sons Ltd., Chichester, Great Britain, 2004.
[16] Shekar, George Chen, Wilson, Jarman, “Bridging in Contaminated Transformer Oil under DC and AC Electric Field”, Journal of Physics, vol. 472, 2013.