The paper describes a simulated experiment that focuses on the numeric computation of magnetic loss in the laminated core of a single-phase power transformer. The students’ laboratory work is part of the library of experiments of the Electrical Machines virtual laboratory and makes use of the two-dimensional open-access electromagnetic field analysis software Finite Element Method Magnetics. The idea of the simulated exercise is to demonstrate how the magnetic loss caused by time-varying excitations affects the magnetic permeability, μ, of the laminated core and the terminal quantities of the energizing winding. A parametric analysis employing different values for the electrical conductivity and maximum hysteresis-induced angle of the laminated material yields five different field problems with increasing magnetic loss. Electric circuits characterized by the (I-V) operating point and reflected impedance of the energizing winding provide the information required to compute the changes in real power ΔP, reactive power ΔQ and magnetically stored energy ΔWm between successive problems characterized by increasing magnetic loss. The concept of reflected impedance helps to explain the physical meaning of the changes in power dissipation and energy storage in the laminated core.
References
[1]
Jiles, D. (1991) Introduction to Magnetism and Magnetic Materials. Springer-Science + Business Media, Berlin. https://doi.org/10.1007/978-1-4615-3868-4
[2]
Stoll, R.L. (1974) The Analysis of Eddy Currents. Oxford University Press, Oxford.
[3]
Nogueira, A.F.L., Weinert, R.L. and Maldonado, L.J.A.S. (2019) Experiments for Teaching CAD Techniques Using Analytic and Finite Element Solutions of Electromagnetic Two-Dimensional Problems with Longitudinal Symmetry. Journal of Electromagnetic Analysis and Applications, 11, 79-99.
https://doi.org/10.4236/jemaa.2019.116006
[4]
Nogueira, A.F.L., Maldonado, L.J.A.S. and Weinert, R.L. (2020) Introduction to Time-Harmonic Analysis of Power Transformers with Laminated Cores Using the Electromagnetic Field Simulator Finite Element Method Magnetics. International Journal of Research and Reviews in Applied Sciences, 44, 9-24.
https://www.arpapress.com/Volumes/Vol44Issue1/IJRRAS_44_1_02.pdf
[5]
Meeker, D.C. (2013) Finite Element Method Magnetics, User’s Manual, Version 4.2.
http://www.femm.info/wiki/HomePage
[6]
Nogueira, A.F.L., da Costa, V.H.P. and Weinert, R.L. (2017) Simulated Experiments for Teaching Mutually-Coupled Circuits CAD Techniques Using Analytic and Finite Element Solutions. Journal of Electromagnetic Analysis and Applications, 9, 183-202. https://doi.org/10.4236/jemaa.2017.911016
[7]
Meeker, D.C. (2006) Finite Element Method Magnetics: Determination of Transformer Operating Point.
http://www.femm.info/examples/mytransformer/mytransformer.zip
[8]
Baltzis, K.B. (2008) The FEMM Package: A Simple, Fast, and Accurate Open Source Electromagnetic Tool in Science and Engineering. Journal of Engineering Science and Technology Review, 1, 83-89. https://doi.org/10.25103/jestr.011.18
[9]
Baltzis, K.B. (2010) The Finite Element Method Magnetics (FEMM) Freeware Package: May It Serve as an Educational Tool in Teaching Electromagnetics? Education and Information Technologies, 15, 19-36.
https://doi.org/10.1007/s10639-008-9082-8
[10]
íñiquez, J., et al. (2005) Magnetic Levitation by Induced Eddy Currents in Non-Magnetic Conductors and Conductivity Measurements. European Journal of Physics, 26, 951-957. https://doi.org/10.1088/0143-0807/26/6/002
[11]
Sinnadurai, R., Ting, C.M. and Zani, N.H.M. (2016) Analysis and Optimization of a Three Phase Linear Generator Using Finite Element Method Magnetics (FEMM). 2016 IEEE Student Conference on Research and Development (SCOReD), Kuala Lumpur, 13-14 December 2016, 1-6.
https://doi.org/10.1109/SCORED.2016.7810092
[12]
Pamme, N. (2006) Magnetism and Microfluidics. Lab on a Chip, 6, 24-38.
https://doi.org/10.1039/B513005K
[13]
Wichert, T. and Kub, H. (2005) Design and Optimization of Switched Reluctance Machines. Proceedings of the XLI International Symposium on Electrical Machines, Jarnołtówek, 14-17 June 2005, 10.
[14]
Rotariu, O., Udrea, L.E., Strachan, N.J.C. and Badescu, V. (2005) Targeting Magnetic Carrier Particles in Tumor Microvasculature—A Numerical Study. Journal of Optoelectronics and Advanced Materials, 7, 3209-3218.
[15]
Picker, R., Altarev, I., Bröcker,J., Gutsmiedl, E., Hartmann, J., Müller, A., Paul, S., Schott, W., Trinks, U. and Zimmer O. (2005) A Superconducting Magnet UCN Trap for Precise Neutron Lifetime Measurements. Journal of Research of the National Institute of Standards and Technology, 110, 357-360.
http://www.nist.gov/jres
https://doi.org/10.6028/jres.110.053
[16]
Zandsteeg, C.J. (2005) Design of a RoboCup Shooting Mechanism. Report 2005.147, Eindhoven University of Technology, Eindhoven.
[17]
Acuña, M.H., Anderson, B.J., Russel, C.T., Wasilewski, P., Kletetschka, G., Zanetti, L. and Omidi, N. (2002) Near Magnetic Field Observations at 433 Eros: First Measurements from the Surface of an Asteroid. Icarus, 155, 220-228.
https://doi.org/10.1006/icar.2001.6772
[18]
Martignoni, A. (2003) Transformadores. 8th Edition, Editora Globo, São Paulo. (In Portuguese)
[19]
Moses, A., Anderson, P., Jenkins, K. and Stanbury, H. (2019) Electrical Steels, Volume 1: Fundamentals and Basic Concepts. The IET Digital Library.
https://doi.org/10.1049/PBPO157F
[20]
Nogueira, A.F.L., Facchinello, G.G. and Ramos, L.A. (2013) Prediction of Magnetizing Currents in Power Transformers Using Numerically Simulated Open-Circuit Tests. International Journal of Research and Reviews in Applied Sciences, 17, 141-149. https://www.arpapress.com/Volumes/Vol17Issue2/IJRRAS_17_2_01.pdf
