Document Type : Research paper


1 Department of Electrical Engineering, Dezful Branch, Islamic Azad University, Dezful, Iran

2 Faculty of Electrical and Computer Engineering, Jundi Shapur University of Technology, Dezful, Iran


Power equipment are subjected to multiple shock voltages during their operations that are generally caused by a lightning strike, switching of electronic power devices, or transient voltages which across available in the power system. These impulses have a frequency range from several kHz to several MHz, which take pulses at very short intervals in several microseconds. Also, the equipment experiences the peak voltage and subsequently peak currents than their nominal values. These variations in voltage and current values, in very short intervals, have destructive effects on these equipment insulated systems as well as on the accuracy of measuring ground impedance. The primary purpose of this study is to investigate the effect of standard and non-standard voltage impulse on power transformers windings by considering the mutual induction of transformer windings. Furthermore In this paper, by applying lightning pulse on power transformer windings for different models of ground voltage distribution system on different disks of transformer windings terminal (20/0.4KV, 100KVA, 9 disks continuous winding) and the disks voltage are calculated as outputs in MATLAB/Simulink. In previous studies, the calculations were in the time domain, while in this study, the ground impedance was measured in the frequency domain. The simulation results show that considering the model RC and considering the mutual induction, the voltage distribution on the disks is higher than other models. This study provides functional information for improving the design of insulations that are installed between windings and core the results of the present research may lead to the minimization of the dielectric failures. Furthermore, the results of this study can be used in future studies about non-standard impulse voltages. This investigation can certainly lead to modifying available standards or creating new standards in power transformers.


  1. Popov, L. Sluis, R. Smeets, “Evaluation of surge-transferred over voltages in distribution transformers”, Electr. Power Syst., vol. 78, pp. 441-449, 2008.
  2. Balaji, S. USA, “Life estimation of transformer insulation under repeated impulses”, IEEE 1st Int. Conf. Cond. Assess. Tech. Electr. Syst. 2013.
  3. Elanin, M. Salama, “Survey on the transformer condition monitoring”, Power. Eng. Large Eng. Syst., 2007.
  4. Okabe, “Voltage-time, and voltage-number characteristics of insulation elements with the oil-filled transformer in EHV & UHV classes”, IEEE Trans. Dielectric. Electric., 2006.
  5. Bjerkan, H. Høidalen, “Detailed high-frequency power transformer modeling in ATP using FEM and MATLAB”, Pres. Europ. EMTP-ATP Conf., 2018.
  6. Gockenbach, “Impact of new lightning and switching impulse definitions on the test results for insulation systems”, Proc. Int. Symp. Electr. Ins. Materials, 2005.
  7. Mitra, A. De, A. Chakrabarty, Investigation on the voltage stresses developed on transformer insulation under non-standard terminal excitations”, IEEE Region Conf., 2009.
  8. Bjerkan, H. Høidalen, “High frequency FEM-based power transformer modeling: investigation on internal stresses due to network-initiated over voltages”, Int. Conf. Power Syst. Tran., 2005.
  9. Tenbohlen, S. Ryder, “Making frequency response analysis measurements: a comparison of the swept frequency and low voltage impulse methods”, Int. Symp. High-Volt. Eng., 2003.
  10. Venkatesan, S. Usa, “Impulse strength of transformer insulation with non-standard wave shapes”, IEEE Trans. Power Deliv., vol. 22, 2007.
  11. Coffeen, J. Britton, J. Rickmann, “A New technique to detect winding displacements in power transformers using frequency response analysis”, Proc. Conf. Power Tech, 2003.
  12. Yousof et al., “A study on suitability of different transformer winding models for frequency response analysis”, Proc. IEEE PES Gen. Meet., 2020.
  13. Zhou, S. Boggs, “Prediction of transient transfer functions at cable transformer interfaces”, IEEE PES Trans. Distrib. Conf. Exhibit. 2006.
  14. Indulkar, M. Thomas, P. Bijwe, “Switching over voltages in line transformer and cable transformer cascades”, Proc. Midwest Symp. Circuits Syst., 2010.
  15. Gustavsen, “Study of transformer resonant over voltages caused by cable-transformer high-frequency interaction”, IEEE Trans. Power Deliv., vol. 25, pp. 770-9, 2010.
  16. Gustavsen, “Application of vector fitting to high frequency transformer modeling”, Int. Conf. Power Syst. Trans., 2003.
  17. Gustavsen, “Wide band modeling of power transformers”, IEEE Trans. Power Deliv., vol. 19, 2004.
  18. Gustavsen, “Frequency dependent modeling of power transformers with ungrounded windings”, IEEE Trans. Power Deliv., vol. 19, pp. 1328-34, 2004.
  19. Pordanjani, W. Xu, “Improvement of vector fitting by using a new method for selection of starting poles”, Electr. Power Syst. Res., vol. 107, pp. 206-212, 2020.
  20. Hendrickx, T. Dhaene, A discussion of rational approximation of frequency domain responses by vector fitting”, IEEE Trans. Power Syst,, vol. 21, pp. 441-3, 2006.
  21. IEC 60060-1, High voltage Test Techniques Part 1: General Definitions and Test Requirements, 2010.
  22. High Voltage Test Techniques IEC Publication 60, 2006.
  23. Yousof, T. Saha, C. Ekanayake, “Investigating the sensitivity of frequency response analysis on transformer winding structure”, Proc. IEEE PES Gen. Meet., 2014.
  24. Bhuyan, S. Chatterjee, Study of effects of standard and non-standard impulse waves on power transformer”, IEEE Int. Joint Conf. Power Electron., 2010.
  25. Bhuyan, S. Chatterjee, Non-linear voltage distribution in windings of power transformer”, Int. J. Eng. Res. Technol, 2012.
  26. Ding, Y. Yao, “A modified lumped parameter model of distribution transformer winding”, Glob. Energy Interconnect., vol. 3, pp. 158-165, 2020.
  27. Cheng, Z. Zhao, “Diagnostic of transformer winding deformation fault types using continuous wavelet transform of pulse response”, Measurement, vol. 140, pp. 167-206, 2019.
  28. Kulkarni, S. Khaparde, “Transformer engineering design and practice”, New York Marcel Dekker, 2004.
  29. Karsai and D. Kerenyi, “Large power transformer”, New York: Elsevier, 1987.
  30. Rahimpour, V. Rashtchi, R. Aghmashehr, “Estimation of number of model units in transformer detailed RCLM model based on terminal measurement in the case of unavailable design data”, Proc. 21st Int. Symp. High Volt. Eng., 2019.
  31. Masdi, “Study of impulse voltage distribution in transformer windings”, 2010 IEEE Int. Conf. Power Energy, 2010.
  32. Sima et al., “Impact of time parameters of lightning impulse on the breakdown characteristics of oil paper insulation”, High Volt., vol. 1, pp. 18-24, 2016.
  33. Ramarao et al., “Calculation of multistage impulse circuit and its analytical function parameters”, Int. J. Pure Appl. Math., vol. 114, pp. 583-592, 2017.