A Novel Fast FEA No-Load Loss Calculation Method for Stacked Core Three Phase Distribution Transformers

Ehsan Hajipour^1, , Mehdi Vakilian¹ and Mohsen Ghafouri¹

¹Electrical Engineering Department, Sharif University of Technology, Tehran, Iran

Cite this paper:
Ehsan Hajipour, Mehdi Vakilian and Mohsen Ghafouri. A Novel Fast FEA No-Load Loss Calculation Method for Stacked Core Three Phase Distribution Transformers. International Transaction of Electrical and Computer Engineers System. 2014; 2(1):34-38. doi: 10.12691/iteces-2-1-6

Abstract

Almost one third of the overall transmission and distribution systems energy losses are lost in distribution transformers, while its core losses account for almost 70% of the total transformers losses. A reasonably fast calculation tool to facilitate the core loss optimization through accurate predetermination of the impact of different design parameters on its losses seems indispensable, for a transformer manufacturer. In this paper, a novel fast 2-D FEA transformer core loss determination method is presented. Assuming the normal component of the magnetic field to be zero, this method reduces the computation time substantially in comparison with the available conventional methods (maintaining the same accuracy level). Employing Gaussian fitting curve, the anisotropic and the non-linear behavior of the magnetic core material are modeled. The extra core losses which occur in the core sheets joints and the stacking holes are simulated accurately in this work. The proposed method is implemented on 12 different commercial size distribution transformers, to verify the speed and the accuracy of this computation method.

Keywords:
anisotropic distribution transformer finite element analysis joints no-load loss

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References:

[1]	Daut, I., Ahmad, D.M.M., Zakaria, S., and Taib, S., “Comparison on losses and flux distribution between two 3-phase distribution transformers 1000 KVA assembled with air gap and without air gap of transformer core lamination”, IEEE Asia-Pacific conf. Applied Electromagnetics (APACE 2007), Dec. 4-6, 2007.
[2]	Ilo, A., Pfutzner, H., Nakata, T., “Critical induction-a key quantity for the optimisation of transformer core operation”, Journal of Magnetism and Magnetic Materials, 215-216. 637-640. 2000.
[3]	Targosz, R., and Topalis, F.V., “Energy efficiency of distribution transformers in Europe”, 9th int. conf. Electrical and Power Quality and Utilization (EPQU 2007), Oct. 9-11, 2007, Barcelona.
[4]	Olivares, J.C., Liu, Y., Canedo, J., Escarela-Perez, R., Driesen, J., and Moreno, P., “Reducing losses in distribution transformers”, IEEE Transaction on Power Delivery, 18 (3). 821-826. Jul. 2003.
[5]	Amoiralis, E.I., Tsili, M.A., Georgilakis, P.S., Kladas, A.G., and Souflaris, A.T., “A parallel mixed integer programming-finite element method technique for global design optimization of power transformers”, IEEE Transaction on Magnetics, 44 (6). 1022-1025. Jun. 2008.
[6]	Kefalas, T.D., Georgilakis, P.S., Kladas, A.G., Souflaris, A.T., and Paparigas, D.G., “Multiple grade lamination wound core: a novel technique for transformer iron loss minimization using simulated annealing with restarts and an anisotropy model”, IEEE Transaction on Magnetics, 44 (6). 1082-1085. Jun. 2008.
[7]	Hernandez, C., Arjona, M.A., and Dong, S.H., “Object-oriented knowledge-based system for distribution transformer design”, IEEE Transaction on Magnetics, 44 (10). 2332-2337. Oct. 2008.
[8]	teNyenhuis, E.G., Girgis, R., and Mechler, G.F., “Other factors contributing to the core loss performance of power and distribution transformers”, IEEE Transaction on Power Delivery, 16 (4). 648-653. Oct. 2001.
[9]	Valkovic, Z., and Rezic, A., “Improvement of transformer core magnetic properties using the step-lap design”, Journal of Magnetism and Magnetic Materials, 112. 413-415. 1992.
[10]	Mechler, G.F., and Girgis, R.S., “Calculation of spatial loss distribution in stacked power and distribution transformer cores”, IEEE Transaction on Power Delivery, 13 (2). 532-537. Apr. 1998.
[11]	National Electrical Manufacturers Association, “NEMA TP2: Standard Test Method for Measuring the Energy Consumption of Distribution Transformers”, Jan. 2005.
[12]	Prieto, R., Cobos, J.A., Bataller, V., Garcia, O., and Ucedci, J., “Study of toroidal transformers by means of 2D approaches”, 28th Annu. IEEE Conf. Power Electronics Specialists (PESC 1997), Jun. 22-27, 1997.
[13]	Valkovic, Z., “Additional losses in three-phase transformer cores”, Journal of Magnetism and Magnetic Materials, 41. 424-426. Feb. 1984.
[14]	Mechler, G.F., and Girgis, R.S., “Magnetic flux distribution in transformer core joints”, IEEE. Transaction on Power Delivery, 15 (1). 198-203. Jan. 2000.
[15]	Mousavi, S.A., “Harmonic core losses calculation in power transformers”, M.Sc. thesis, University of Tehran, Tehran, Iran, 2008.
[16]	Roshen, W.A., “A practical, accurate and very general core loss model for non-sinusoidal waveforms”, IEEE Transaction on Power Electronics, 22 (1). 30-40. Jan. 2007.
[17]	Moses, A.J., “Prediction of core losses of three phase transformers from estimation of the components contributing to the building factor”, Journal of Magnetism and Magnetic Materials, 254-255. 615-617. 2003.
[18]	Khelil, M., Elleuch, M., “Modeling of the air-gaps of overlapped joints in three-phase transformer iron core for using by FEM”, IEEE Multi-Conference on Systems, Signals and Devices (SSD 2009), Mar. 23-26, 2009.
[19]	Hajipour, E., Rezaei, P., Vakilian, M., Ghafouri, M., “Power Transformer No-Load Loss Prediction with FEM Modeling and Building Factor Optimization,” Journal of Electromagnetic Analysis and Applications, 3 (10). 430-438. 2011.