© The Institution of Engineering and Technology
This article shows results of using surface impedances (Z SURFACE) in 3D FEM linear model to calculate zero-sequence magnetising impedances (Z 0M) of 3-phase core-type transformers. Initially, results with and without Z SURFACE are compared to obtain certainty about model validity. Compared results are magnetising reactances and active power losses in tank during Z 0M tests. Subsequently, results of 3D models with Z SURFACE are compared with Z 0M measurements at different currents, to consider nonlinearity of tank steel. An equivalent permeability for tank steel is estimated for each test point, and accurate results from model are obtained for magnetising reactances. An approximate curve for this equivalent permeability is also found, as in a previous 2D method, and both curves are similar from each other. It is shown that active power losses in tank cannot be properly computed using these 3D linear models. This fact cannot be observed by previous 2D models and it indicates that active power losses in tank are influenced by other phenomena, which are not considered by these FEM models. Main contributions are the application of Z SURFACE as a powerful tool to compute Z 0M, and an analysis of active power losses in tank which could not be performed by previous 2D models.
References
-
-
1)
-
12. Venegas, M., Escarela, R., Niewierowicz, T.: ‘3D finite element estimation of stray losses in three-phase transformers’, J. Appl. Comput. Sci., 2008, 16, (1), pp. 89–100.
-
2)
-
3. Sorrentino, E., Burgos, J.: ‘Application of 2D linear models for computing zero-sequence magnetizing impedances of 3-phase core-type transformers’, Electr. Power Syst. Res., 2014, 117, pp. 123–133.
-
3)
-
14. Guérin, C., Tanneau, G., Meunier, G.: ‘3D eddy current losses calculation in transformer tanks using the finite element method’, IEEE Trans. Magn., 1993, 29, (2), pp. 1419–1422.
-
4)
-
5)
-
18. IEC Std. 60076–1: , 2011.
-
6)
-
20. IEEE Std. C57.12.90: , 2010.
-
7)
-
6. Yuferev, S., Ida, N.: ‘Surface impedance boundary condition: a comprehensive approach’ (CRC Press, Boca Raton, USA, 2009).
-
8)
-
10. Žarko, D., Maljkovic, Z., Štefan, S.: ‘Calculation of losses in the core clamps of a transformer using 3-D finite-element method’. Proc. Polish Symp. on Applied Electromagnetics (SAEM), Ohrid, Macedonia, June 2006, p. 4.
-
9)
-
1. Kulkarni, S., Khaparde, S.: ‘Transformer engineering: design, technology, and diagnostics’ (CRC Press, Boca Raton, USA, 2012).
-
10)
-
17. Sorrentino, E., Burgos, J.: ‘About the difference between zero-sequence magnetizing impedances of a 3-phase core-type transformer’, Electr. Power Syst. Res., 2014, 116, pp. 439–443.
-
11)
-
16. Sorrentino, E., Burgos, J.: ‘Application of 2D linear modeling for computing zero-sequence short-circuit impedances of 3-phase core-type YNynd transformers’, Electr. Power Syst. Res., 2015, 122, pp. 1–9.
-
12)
-
5. Ngnegueu, T., Mailhot, M., Munar, A., et al: ‘Zero phase sequence impedance and tank heating model for three phase three leg core type power transformers coupling magnetic field and electric circuit equations in a finite element software’, IEEE Trans. Magn., 1995, 31, (3), pp. 2068–2071.
-
13)
-
9. Guérin, C., Meunier, G., Tanneau, G.: ‘Surface impedance for 3D non-linear eddy current problems-application to loss computation in transformers’, IEEE Trans. Magn., 1996, 32, (3), pp. 808–811.
-
14)
-
19. IEC Std. 60076–8: , 1997.
-
15)
-
2. Garin, A.: ‘Zero-phase-sequence characteristics of transformers. Part II’, Gen. Electr. Rev., 1940, 43, (4), pp. 174–179.
-
16)
-
11. Holland, S., O'Connell, G., Haydock, L.: ‘Calculating stray losses in power transformers using surface impedance with finite elements’, IEEE Trans. Magn., 1992, 28, (2), pp. 1355–1358.
-
17)
-
8. Susnjic, L., Haznadar, Z., Valkovic, Z.: ‘3D finite-element determination of stray losses in power transformer’, Electr. Power Syst. Res., 2008, 78, (10), pp. 1814–1818.
-
18)
-
13. Higuchi, Y., Koizumi, M.: ‘Integral equation method with surface impedance model for 3D eddy current analysis in transformers’, IEEE Trans. Magn., 2000, 36, (4), pp. 774–779.
-
19)
-
7. Kralj, L., Miljavec, D.: ‘Stray losses in power transformer tank walls and construction parts’. Proc. XIX Int. Conf. on Electrical Machines (ICEM), Rome, Italy, September 2010, p. 4.
-
20)
-
4. Allcock, R., Holland, S., Haydock, L.: ‘Calculation of zero phase sequence impedance for power transformers using numerical methods’, IEEE Trans. Magn., 1995, 31, (3), pp. 2048–2051.
http://iet.metastore.ingenta.com/content/journals/10.1049/iet-smt.2018.5088
Related content
content/journals/10.1049/iet-smt.2018.5088
pub_keyword,iet_inspecKeyword,pub_concept
6
6