Characterization of Power Transformer Electromagnetic Forces Affected by Winding Faults

Document Type : Research paper

Authors

1 Department of Electrical Engineering, Azarbaijan Shahid Madani university, Tabriz, Iran. Email: behjat@azaruniv.edu

2 Department of Electrical Engineering, Engineering Faculty, Azarbaijan Shahid Madani University, Tabriz, Iran

3 Department of Electrical Engineering, Engineering Faculty, Shahid Madani University, Tabriz, Iran

Abstract

Electromagnetic forces in power transformer windings are produced by interaction between the leakage fluxes and current passing them. Since the leakage flux distribution along the windings height is in two axial and radial directions, so the electromagnetic forces have two components, radial and axial. There is a risk that a large electromagnetic force due to the short circuit or inrush currents, can cause the windings to be deform, rupture, and/or displace, if the transformer and winding holders structure is not designed or assembled properly. Also, these mechanical changes can damage insulation between two or more adjacent turns of a winding and so, produce the local inter-turn fault. Occurrence of any fault in windings will change the electromagnetic force distribution in transformers and will cause developing secondary faults. Hence, this contribution is aimed at characterizing the electromagnetic forces behavior in power transformers and determines the changes of force values after occurring winding mechanical and inter-turn. The study keeps at disposal a two-winding, three phase, 8 MVA power transformer, on their windings faults are imposed and investigated through the FEM analysis. The accuracy of the created FEM model is firstly validated using analytical methods for transformer healthy condition, and then the winding shorted turn fault along with the mechanical faults are considered using 3D FEM model. The extracted characteristic signatures attained to different type of winding faults is expected to be useful at the design stage of power transformers.

Keywords

Main Subjects


[1]     Zhang, Z.W., Tang, W.H., Ji, T.Y., Wu, Q.H., “Finite-element modeling for analysis of radial deformations within transformer windings,” IEEE Trans. Power Deliv., vol. 25, no. 5, pp. 2297-2305, 2014
[2]    A.A. Adly, “Computation of inrush current forces on transformer windings,” IEEE Trans. Magn., vol. 37, no. 4, pp. 2855-2857, 2001.
[3]    G. B. Kumbhar and S.V. Kulkarni, “Analysis of short-circuit performance of split-winding transformer using coupled field-circuit approach,” IEEE Trans. Power Deliv., vol. 22, no. 2, pp. 936-943, 2007.
[4]    J. Faiz, B.M. Ebrahimi, and T. Noori, “Three-and two-dimensional finite-element computation of inrush current and short-circuit electromagnetic forces on windings of a three-phase core-type power transformer,” IEEE Trans. Magn., vol. 44, no. 5, pp. 590-597, 2008.
[5]    H.M. Ahn, J.Y. lee, J.K. Kim, and Y.H. Oh, “Finite-element analysis of short-circuit electromagnetic force in power transformer,” IEEE Trans. Ind. Appl., vol. 47, no. 3, pp. 1267-1272, 2011.
[6]    A.G. Kladas, M.P. Papadopoulos, and J.A. Tegopoulos, “Leakage flux and force calculation on power transformer windings under short-circuit: 2D and 3D models based on the theory of images and the finite element method compared to measurements,” IEEE Trans. Magn., vol. 30, no. 5, pp. 3487-3490, 1994.
[7]    A.C. De Azevedo, I. Rezende, A.C. Delaiba, J.C. De Oliveira, “Investigation of transformer electromagnetic forces caused by external faults using FEM,” In Proc. of the IEEE PES Transm. Distrib. Conf. Exposition: Lat. Am., 2006.
[8]    Y.Q. Tang, J.Q. Qiao, and ZH. Xu, “Numerical calculation of short circuit electromagnetic forces on the transformer winding,” IEEE Trans. Magn., vol. 26, no. 2, pp. 1039-1041, 1990.
[9]    T. Renyuan, L. Yan, L. dake, T. Lijian, “Numerical calculation of 3D eddy current field and short circuit electromagnetic force in large transformers,” IEEE Trans. Magn., vol. 28, no. 2, pp. 1418-1421, 1992.
[10] S. Jamali, M. Ardebili, and K. Abbaszadeh, “Calculation of short circuit reactance and electromagnetic forces in three phase transformer by finite element method,” Electr. Mach. Syst. In Proc. Of the 8th Int. Conf., vol. 3, 2005.
[11] M. Ardebili, K. Abbaszadeh, S. Jamali, H.A. Toliyat, “Winding arrangement effects on electromagnetic forces and short-circuit reactance calculation in power transformers via numerical and analytical methods,” In Proc. of the IEEE 12th Biennial Conf., 2006.
[12] M., Zhiqiang and Z. Wang, “The analysis of mechanical strength of HV winding using finite element method. Part I Calculation of electromagnetic forces,” Univ. Power Eng. Conf., vol. 1, 2004.
[13] N.Y. Abed and O.A. Mohammed, “Modeling and characterization of transformers internal faults using finite element and discrete wavelet transforms,” IEEE Trans. Magn., vol. 43, no. 4, pp. 1425-1428, 2007.
[14] K. Guven and T. Gundogdu, “Effect of the tap winding configurations on the electromagnetic forces acting on the concentric transformer coils,” In Proc. of the 3rd Int. Conf. Electr. Power Energy Convers. Syst., 2013.
[15] J. F. Araujo, E. G. Costa, F. L. M. Andrade, A. D. Germano, and T. V. Ferreira, “Methodology to Evaluate the Electromechanical Effects of Electromagnetic Forces on Conductive Materials in Transformer Windings Using the Von Mises and Fatigue Criteria,” IEEE Trans. Power Deliv., vol. 31, no. 5, pp. 2206-2214, 2016.
[16] D. Geißler; T. Leibfried, “Short-Circuit Strength of Power Transformer Windings-Verification of Tests by a Finite Element Analysis-Based Model,” IEEE Trans. Power Deliv., vol. 32, no. 4, pp. 1705-1712, 2017.
[17] N. Hashemnia, A. Abu-Siada and S. Islam, “Improved power transformer winding fault detection using FRA diagnostics – part 1: axial displacement simulation,” IEEE Trans. Dielect. Elect. Insul., vol. 22, no. 1, pp. 556-563, 2015.
[18] S.V. Kulkarni and S.A. Khaparde, Transformer engineering: design and practice, vol. 25. CRC Press, 2nd ed, 2012.
[19] W. J McNutt, W.M.Johnson, and R.A.Nelson, “Power transformer short-circuit strength-requirements, designer, and demonstration,” IEEE Trans. Power Appl. Syst., PAS-89, no. 8, pp. 1955-1969, 1970.
[20] R.M. Del-Vecchio, B. Poulin, and P.T. Feghali, Transformer design principles: with applications to core-form power transformers, FL: CRC Press, US, 2nd ed, 2010.
[21] J.A.S.B. Jayasinghe and Z.D. Wang, “Winding movement in power transformers: a comparison of FRA measurement connection methods,” IEEE Trans. Dielect. Elect. Insul., vol. 13, no. 6, pp.1342-1349, 2006.
[22] M. Bagheri, S.N. Mohammad, and T. Blackburn, “Advanced transformer winding deformation diagnosis: moving from off-line to on-line,” IEEE Trans. Dielect. Elect. Insul., vol. 19, no. 6, pp. 1860-1870, 2012.
[23] IEEE Guide for Protective Relay Applications to Power Transformers, IEEE C37.91-2000.
[24] L.M.R. Oliveira and A.J. Cardoso, “On-line diagnostics of transformer winding insulation failures, by Park's Vector Approach,” In Proc. of the  9th Int. Electr. Insul. Conf., 2001.
[25] K.L. Butler-Purry, M. Bagriyanik, M.J. Mousavi, P. Palmer-Buckle, “Experimental investigation of internal short circuit faults leading to advanced incipient behavior and failure of a distribution transformer,” In Proce. IEEE PES Power Syst. Conf. Expos., 2004.
[26] V. Behjat and A. Vahedi, “An experimental approach for investigating low-level interturn winding faults in power transformers,” Spring Electr. Eng., vol. 95, no. 2, pp. 135-145, 2013.
[27] B. Ravindranath and M. Chander, Power syst. Protection. switchgear, New Age International, 1977.
[28] Y.G. Paithankar, S.R. Bhide, Fundamentals of Power System Protection, PHI Learning Pvt. Ltd. 2004.
[29] A. Vahedi and V. Behjat, “Online monitoring of power transformers for detection of internal winding short circuit faults using negative sequence analysis,” Eur. Trans. Electr. Power, vol. 21, no. 1, pp. 196-211, 2011.
[30] M.R. Feyzi and M. Sabahi, “Finite element analysis of short circuit forces in power transformers with asymmetric conditions,” In Proce. of the IEEE Int. Symp. Ind. Electron., pp. 576-581, 2008.
[31] A.C. Franklin, D.P. Franklin, The J&P TransformerBook, Butterworth Ltd, London, 1993.
The Short Circuit Performance of Power Transformers, Brochure CIGRE WG 12.19, 2002.