Non-Linear Eddy Current Loss and Thermal Analysis on Transformer Cover

Year 2019, Volume: 32 Issue: 2, 558 - 570, 01.06.2019

Mohammad Zia Zahedı , İres Iskender

Abstract

High current conductors of transformers cause to produce losses and
thermal problems in their tank cover. Finite Difference (FD) Method (FDM)
magnetic analysis is used to find out an exact estimation of the magnetic field
and the losses near the bushings in the transient solution, considering the
non-linear magnetic permeability of the cover plate, because FDM is more
flexible to deal with the nonlinear constitutive law and easy-to-be implemented
especially in the case of simple geometry. Finite Element Method (FEM) thermal
analysis is used to determine the plate temperature based on magnetic FD
analysis, taking account non-linear heat flux boundary condition. A calibration
procedure is used between the analyses to ensure the precision of assumptions.
The reliability of the technique, confirmed by experimental and FEM results.

Keywords

Eddy current loss, Finite Difference method, Finite element simulation, Hot spot temperature, Transformer cover

References

• Turowski, J. and Pelikant, A., "Eddy Currents Losses and Hot-Spot Evaluation in Cover Plates of Power Transformers," Proc. Inst. Elect. Eng. Elect. Power Appl., vol. 144, no. 6, pp. 435-440, (1997).
• Olivares, J. C., Perez, R. E., Kulkarni, S. V., Leon, F. d., and Vega, M. A. V., "2D Finite-Element Determination of Tank Wall Losses in Pad-Mounted Transformers," Electric Power Systems Research, vol. 71, pp. 179-185, (2004).
• Zahedi, M. Z. and Iskender, I., "3D FEM Optimal Design of Transformer Cover Plates to Decrease Stray Losses and Hot Spot Temperature," International Journal on Technical and Physical Problems of Engineering (IJTPE), vol. 8, no. 3, pp. 56-60, (2016).
• Olivares, J. C., Perez, R. E., Kulkarni, S. V., Leon, F. d., Vasquez, E. M., and Anaya, O. H., "Improved Insert Geometry for Reducing Tank-Wall Losses in Pad-Mounted Transformers," IEEE Trans. on Power Delivery, vol. 19, no. 3, pp. 1120-1126, (2004).
• Vecchio, R. M. D., Poulin, B., Feghali, P. T., Shah, D. M., and Ahuja, R., Transformer Design Principles: With Applications to Core-Form Power Transformers, USA: CRC Press, Boca Raton, FL, (2010).
• Maximov, S., Olivares-Galvan, J. C., Magdaleno-Adame, S., Escarela-Perez, R., and Campero-Littlewood, E., "New Analytical Formulas for Electromagnetic Field and Eddy Current Losses in Bushing Regions of Transformers," IEEE Trans. Magnetics, vol. 51, (2015).
• Zahedi, M. Z. and Iskender, I., "FDM ELECTROMAGNETIC ANALYSIS IN BUSHING REGIONS OF TRANSFORMER," International Journal on Technical and Physical Problems of Engineering (IJTPE), vol. 10, no. 34, pp. 27-33, Mar. (2018).
• Lopez-Fernandez, X. M., Penabad-Duran, P., Turowski, J., and Ribeiro, P. M., "Non-linear heating hazard assessment on transformer covers and tank walls," Przeglad Elektrotech. (Elect. Rev.), vol. 88, no. 7b, pp. 28–31, (2012).[9] Vecchio, R. M. D. and Ahuja, R., "Analytic Nonlinear Correction to the Impedance Boundary Condition," IEEE Trans. Magnetics, vol. 49, no. 12, pp. 5687–5691, (2013).
• S. Maximov, R. E. P., Adame, S. M., Galvan, J. C. O., and Littlewood, E. C., "Calculation of Nonlinear Electromagnetic Fields in the Steel Wall Vicinity of Transformer Bushings," IEEE Trans. Magnetics, vol. 51, no. 6, (2015).
• Fernandez, X. M. L., Duran, P. P., and Turowski, J., "Three Dimensional Methodology for the Overheating Hazard Assessment on Transformer Covers," IEEE Trans. Industry Applications, vol. 48, pp. 1549-1555, (2012).
• Durana, P. P., Fernandez, X. M. L., and Turowski, J., "3D Non-Linear Magneto-Thermal Behavior on Transformer Covers," Electric Power Systems Research, vol. 121, pp. 333-340, (2015).
• Maximov, S., Escarela-Perez, R., Olivares-Galvan, J. C., Guzman, S. J., and Campero-Littlewood, E., "New Analytical Formula for Temperature Assessment on Transformer Tanks," IEEE Trans. Power Delivery, vol. 31, no. 3, pp. 1122-1131, (2016).
• Sadiku, M. N. O., Elements of electromagnetics, Oxford University Press, New York, (2011).
• Inc., A., "User’s Guide - Maxwell 3D/ANSYS Maxwell," 15 ed., Canonsburg, PA, USA, (2012).
• Sadiku, M. N. O., Numerical techniques in electromagnetics, CRC Press, New York, (2001).
• Gillott, D. H. and Calvert, J. F., "Eddy current loss in saturated solid magnetic plates, rods, and conductors," IEEE Trans. Magn., vol. 1, no. 2, pp. 126–137, (1965).
• Holman, J. P., Heat transfer, McGraw-Hill, New York, (2010).
• Internet: Heat Distribution in a Circular Cylindrical Rod, In MathWorks Online. https://www.mathworks.com/help/pde/examples/heat-distribution-in-a-circular-cylindrical-rod.html?s_tid=srchtitle, (2018).
• Internet: Nonlinear Heat Transfer In a Thin Plate, In MathWorks Online. https://www.mathworks.com/help/pde/examples/nonlinear-heat-transfer-in-a-thin-plate.html?searchHighlight=Nonlinear%20Heat%20Transfer%20In%20a%20Thin%20Plate&s_tid=doc_srchtitle, (2018).