Commenced in January 2007
Frequency: Monthly
Edition: International
Paper Count: 31108
The Effect of Transformer’s Vector Group on Retained Voltage Magnitude and Sag Frequency at Industrial Sites Due to Faults

Authors: M. N. Moschakis, V. V. Dafopoulos, I. G. Andritsos, E. S. Karapidakis, J. M. Prousalidis


This paper deals with the effect of a power transformer’s vector group on the basic voltage sag characteristics during unbalanced faults at a meshed or radial power network. Specifically, the propagation of voltage sags through a power transformer is studied with advanced short-circuit analysis. A smart method to incorporate this effect on analytical mathematical expressions is proposed. Based on this methodology, the positive effect of transformers of certain vector groups on the mitigation of the expected number of voltage sags per year (sag frequency) at the terminals of critical industrial customers can be estimated.

Keywords: Industrial Design, Power Systems, Power Quality, phase shift, balanced and unbalanced faults, voltage sags (or dips)

Digital Object Identifier (DOI):

Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 9854


[1] S. S. Deswal, R. Dahiya, and D. K. Jain, “Application of Boost Converter For Ride-through Capability of Adjustable Speed Drives During Sag and Swell Conditions”, World Academy of Science, Engineering and Technology, Issue 23, November 2008.
[2] H. Nasiraghdam, and A. Jalilian, “Balanced and Unbalanced Voltage Sag Mitigation Using DSTATCOM with Linear and Nonlinear Loads”, World Academy of Science, Engineering and Technology, Issue 4, April 2007.
[3] Μ. Bollen, Understanding Power Quality Problems: Voltage Sags and Interruptions, Anderson P.M., 2000, pp. 190-198.
[4] M. Aung, and J. Milanovic, “The Influence of Transformer Winding Connections on the Propagation of Voltage Sags”, IEEE Trans. on Power Delivery, vol. 21, no. 1, pp. 262–269, January 2006.
[5] M. McGranaghan, D. Mueller, and M. Samotyj, “Voltage Sags in Industrial Systems”, IEEE Trans. on Industry Applications, vol. 29, no. 2, pp. 397–403, March/April 1993.
[6] J. Moshtagh, and H. P. Souraki “Characteristics Analysis of Voltage Sag and Voltage Swell in Multi-Grounded Four-Wire Power Distribution Systems”, World Academy of Science, Engineering and Technology, Issue 31, July 2009.
[7] M. Moschakis, and N. Hatziargyriou, “Analytical Calculation and Stochastic Assessment of Voltage Sags”, IEEE Trans. on Power Delivery, vol. 21, no. 3, pp. 1727–1734, July 2006.
[8] M. Bollen, “Fast assessment methods for voltage sags in distribution systems,” IEEE Trans. Industry Applications, vol. 32, no. 6, pp. 1414- 1423, November/December 1996.
[9] M. Moschakis, S. Loutridis, V. Dafopoulos, A. Anastasiadis, T. Tomtsi, E. Karapidakis, and A. Tsikalakis, “Prediction of Voltage Sags Applying the Method of Critical Distances to Meshed Power Networks”, in Proc. of IEEE PMAPS (Probabilistic Methods Applied to Power Systems) Conference, pp. 570-575, Istanbul, Turkey, June 10-14, 2012.
[10] L. E. Conrad, "Proposed Chapter 9 for Predicting Voltage Sags (Dips) in revision to IEEE Std 493, the Gold Book," IEEE Trans. Ind. Applicat., vol. 30, no. 3, pp. 805-821, May/June 1994.
[11] N. Patne, and K. Thakre, “Stochastic Estimation of Voltage Sags due to Faults in the Power System by Using PSCAD/EMTDC Software as a Tool for Simulation”, Electric Power Quality and Utilisation, Journal Vol. XIII, No. 2, 2007.
[12] J. Martinez, J. Martin-Arnedo, “Voltage Sag Stochastic Prediction Using an Electromagnetic Transient Program”, IEEE Trans. Power Delivery, vol. 19, no. 4 pp. 1975-1982, October 2004.
[13] IEC 60076-1 Standard, Power Transformers – Part 1: General, 1999.
[14] IEEE C57.12.00 Standard, General Requirements for Liquid Immersed Distribution, Power, and Regulating Transformers, 2000.
[15] IEEE C57.12.70 Standard, Terminal Markings and Connections for Distribution and Power Transformers, 2000.
[16] H. Joshi, Residential, Commercial and Industrial Electrical Systems – Vol. I: Equipment & Selection, Tata McGraw-Hill, 2008, pp. 140.
[17] J. Parmar, Vector Group of Transformer,
[18] J. Grainger, and W. Stevenson, Power System Analysis, McGraw-Hill, 1994, pp. 449-459.
[19] Manitoba HVDC Research Center, PSCAD-Power Systems Simulation Software, Version 4.2, Canada, 2004.