Transformer saturation is an area of major concern as the transformers are designed to run near peak magnetizing flux value and if voltage/frequency (V/f) ratio increases, it may cause the transformer to reach into saturation, which can affect normal operation of the transformer and even cause mal-operation of the protective equipments. This paper explains different techniques of transformer saturation detection and current waveform improvement.

1. Magdalena Puskarczyk1, Brice Jamieson1, WojciechJurczak "The influence of core shape and material nonlinearities to corner losses of inductive element" ABB Corporate Research Centre, Kraków, Poland.
2. S. V. Kulkarni, S. A. Khaparde Transformer Engineering Design and Practice.
3. G. Sybille, M. M. Gavrilovic, J. Belanger, 1985 "Transformer saturation effect on EHV system overvoltages" IEEE Transaction on Power Apparatus and System, Vol-PAS-104, No. 3.
4. Manpreet S Manna, Sanjay Marwaha, Gurmeet S Grewal, SarpreetKaur, Sept 2006 "3D FEM analysis for overfluxing in power transformer", National Conference on Computational Intelligence for Emerging Electrical Power System(CIEEPS06), 255-258.
5. Hindle P J, Robinson N. , March 1997 "Coping with abnormal flux conditions when applying transformer protection". IEE Conference Publication.
6. Sonnemann W, Wanger C, Rockerfeller G. , 1958 "Magnetizing inrush phenomena in transformer banks". AIEE Tranc. Part111. Vol. 77, 884-92.
7. T. R. Specht, 1951 "Transformer magnetizing inrush current",AIEE Trans. pt. I, vol. 70, 323–328
8. D. A. Koppikar, S. V. Kulkarni, S. A. Khaparde,B. Arora 1998, "A modified approach to overfluxing analysis of transformer" Electrical Power And Energy Systems, Elsevier Science Ltd,Vol-20,No. -4,235-239.
9. Stuehm, D. L, Mork, B. A. and Mairs, D. D. , 1989, "Five- legged core transformer equivalent circuit". IEEE Tranc. on Power Delivery. Vol-4, No. -3,1786-1790.
10. Mairs,D. D,Stuehm,D. L and Mork,B. A. 1989, "Over-voltages on five-legged core transformer on rural electric systems" IEEE Tranc. On power delivery, Vol-25 no. -2, 366-370.
11. Arthuri, C. M. 1991 "Transient simulation and analysis of three phase five limb step-up transformer" IEEE Tranc. on Power Delivery. Vol-6, No. -1, 196-203.
12. David C. Yu,James, C. Cummins, Zhuding Wang, Hong-Jun Yoon,LjubomirA. kojovic, , 2001, "Correction of current transformer distorted secondary currents due to saturation using artificial neural network" IEEE Transactions on Power Delivery, Vol-16,No-2.
13. S. Haykin, 1994 "Neural networks-A comprehensive foundation" IEEE Press. 181.
14. Rebizant W, 2000, "ANN based detection of OS conditions in power systems",12th Int. Conf. on Power System Protection, 51-56.
15. D. C. Yu, Z. Wang, J. C. Cummins, H. J. Yoon, L. A. Kojovic and D. Stone, 1999, "Neural network for current transformer saturation correction", IEEE Transm. Distrib. Conference, New Orleans, L. A.
16. K. W. Chen and S. T. Glad, 1991, "Estimation of the primary current in a saturated transformer", Proceedings of IEEE Conference on Decision and Control, 116-124.
17. Z. Lu, J. S. Smith, and Q. H. Wu, 2008 "Morphological lifting scheme for current transformer saturation detection and compensation" IEEE Transactions on Circuits And Systems—I: Regular Papers,Vol- 55,No. -10.
18. P. K. Gangadharan, T. S. Sindhu and A. Klimek, Mar 2007 "Influence of current transformer saturation on on-line current differential protection algorithm". IET Generat. Tranc, Distrib. Vol- 1,No. -2, 270-277.
19. W. Sweldens,1998, "The lifting scheme:Aconstruction of second generation wavelets," SIAM J. Math. Anal. , Vol-29, No-2, 511–546.
20. K. Vu and A. Khan, 1999, Waveform reconstruction from distorted (saturated) currents", U. S Patent(#5974361).
21. J. Serra, 1982 "Image analysis and mathematical morphology" London U. K. Academic.
22. D. Shi, J. Buse, Q. H. Wu, C. X. Guo. , 2013 "Current transformer saturation compensation based on a partial non-linear model" Elsevier Electrical Power System Research, 34-40.
23. Louie J. Powell, J. R. ,1979, "Current transformer burden and saturation" IEEE Transaction on Industry Application, Vol IA-15, No. 3.
24. David C. Yu,James, C. Cummins, Zhuding Wang, Hong-Jun Yoon,LjubomirA. kojovic, , 2001, "Correction of current transformer distorted secondary currents due to saturation using artificial neural network" IEEE Transactions on Power Delivery, Vol-16,No-2.
25. Jiuping Pan, Khoi Vu And Yi Hu, 2004"An efficient compensation algorithm for current transformer saturation effects" IEEE Transactions on Power Delivery, Vol. 19, No. 4, 1623.
26. B. Kasztenny, E. Rosolowski, M. Lukowicsz and J. Izykowski, 1997, "Current related relaying algorithms immune to saturation of current transformers", Conf. Developments in Power System Protection.
27. T. Bunyagul, P. Crossley and P. Gale, 2001, "Overcurrent protection using signals derived from saturated measurement CTs", IEEE Summer Meeting, Canada.
28. P. Silveste and Madabushi V. K. Chari, 1970 "Finite element solution of saturable magnetic field problems" IEEE Transactions on Power Apparatus and Systems, Vol. -89, No. 7.
29. A. M. Winslow,1965, "Magnetic field calculation in an irregular triangle mesh," Proc. Internatl. Symp. on Magnet Technology, 170-181.
30. Z. H. Shaikh, H. Yamashita, E. Nakamae, 1988 "A three dimensional magnetic field analysis by a novel finite element method using magnetic flux density directly as an unknown variable" IEEE Transactions on Power Delivery, Vol. 3, No. 1.
31. P. Concus, 1965, "On the calculation of nonlinear magnetostatic fields," Proc. Internatl. Symp. on Magnet Technology, 164-169.

Finite Element Method Transformer Overfluxing.