© The Institution of Engineering and Technology
To reduce circulating current losses in stator strands of hydrogenerator, strand transposition is widely used in stator bars. At present, the traditional analytical method for calculating circulating current losses cannot accurately simulate the distribution of leakage magnetic field, which will bring a large deviation to the calculation result and not benefit the winding design. The numerical calculation method for circulating current losses in stator bar is presented in this study, by which the leakage magnetic field distribution of stator transposition bar can be described in detail through establishing threedimensional actual transposition model. The 0°/360°/0° transposition bar in a 180 MW hydrogenerator is taken as an example and the circulating current losses in stator bar strands are calculated. The causes of errors in traditional analytical method are discussed through the comparison of the leakage magnetic field distribution obtained by numerical calculation method and traditional analytical method.
References


1)

1. Xu, S.C., Wu, Z.T.: ‘A new transposition technique of the stator bars of large generators (I)’, Large Electr. Mach. Hydraulic Turbine, 1992, 1992, (1), pp. 1–5.

2)

2. Zou, J.B., Zhao, B., Xu, Y.X., Shang, J., Liang, W.Y.: ‘A new end winding transposition to reduce windings eddy loss for 2 MW direct drive multiunit PMSM’, IEEE Trans. Magn., 2012, 48, (11), pp. 3323–3326 (doi: 10.1109/TMAG.2012.2201701).

3)

3. Schrefler, B., Gori, R.: ‘The effects of strand transposition on the stiffness matrix of superconductor core elements’, IEEE Trans. Magn., 1988, 24, (2), pp. 1037–1040 (doi: 10.1109/20.11405).

4)

4. Reddy, P.B., Jahns, T.M., Bohn, T.P.: ‘Transposition effects on bundle proximity losses in highspeed PM machines’. IEEE Energy Conversion Congress and Exposition, San Jose, USA, September 2009, pp. 1919–1926.

5)

5. Fujita, M., Kabata, Y., Tokumasu, T., Nagakura, K., Kakiuchi, M., Nagano, S.: ‘Circulating currents in stator coils of large turbine generators and loss reduction’, IEEE Trans. Ind. Appl., 2009, 45, (2), pp. 685–693 (doi: 10.1109/TIA.2009.2013572).

6)

6. Xie, D.X., Yan, X.K., Yao, Y.Y.: ‘Circulating current computation and transposition design for large current winding of transformer with multisection strategy and hybrid optimal method’, IEEE Trans. Magn., 2000, 36, (4), pp. 1014–1017 (doi: 10.1109/20.877613).

7)

7. Bennington, B.J., Brenner, W.C.: ‘Transpositions in turbogenerator coil sides short circuited at each end’, IEEE Trans. Power Appar. Syst., 1970, 89, (8), pp. 1915–1921 (doi: 10.1109/TPAS.1970.292776).

8)

8. Liang, Y.P., Yu, H.H., Bian, X.: ‘Analysis and calculation of slot leakage reactance in the stator bar strands of deficient transposition’, COMPEL J., 2013, 32, (3), pp. 1098–1111 (doi: 10.1108/03321641311306169).

9)

9. Xu, C.Q., Luo, R.J.: ‘Circulating current and transposition of the stator bars of large generators’, Large Electr. Mach. Hydraulic Turbine, 1986, 1986, (3), pp. 15–22.

10)

10. Han, L., Shi, X.K., Guo, N.: ‘New methods for the stator bar transpositions of hydrogenerators’, Large Electr. Mach. Hydraulic Turbine, 2009, 2009, (3), pp. 1–5.

11)

11. Liang, Y.P., Sun, Y., Sun, Y.T.: ‘Calculation and analysis on circulating current losses in the stator bar strands of a 1000 MW hydrogenerator’, Electr. Mach. Control, 2011, 15, (7), pp. 65–70.

12)

12. Guo, N., Han, L., Shi, X.K.: ‘Analysis and comparison of four transposition methods in the stator bar of hydrogenerator’, J. Chongqing Univ., 2007, 30, (2), pp. 42–45.

13)

13. Jiang, K.X., Han, L.: ‘Calculation and analysis on stator bar transposition of hydrogenerator of tian ba qi’, Dong Fang Electr. Mach., 1995, 1995, (2), pp. 23–30.

14)

14. Du, C.X., Gui, W.H., Zhou, G.H.: ‘Excessive losses and temperature field calculation of stator coil bars in aircooled large hydrogenerators’, Proc. CSEE, 2012, 32, (12), pp. 111–119.

15)

J. Haldemann
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Transpositions in stator bars of large turbogenerators.
IEEE Trans. Energy Convers.
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560

16)

16. Tang, R.Y., Xu, G.R., Tian, L.J., Zhao, D.Q., Xu, Y.: ‘Calculation of end region magnetic field and circuit equations method’, IEEE Trans. Magn., 1990, 26, (2), pp. 496–500.

17)

17. Hattori, K., Id, K., Takahashi, K., Kobashi, K., Okabe, H., Watanabe, T.: ‘Performance assessment study of a 250MVA aircooled turbo generator’. IEEE Int. Conf. Generators and Drives, Madison, USA, June 2003, pp. 124–128.

18)

18. Guo, Y.G., Wang, X.F., Zhu, J.G., Ramsden, V.S.: ‘Analysis of circulating currents among the stator bar strands of large turbinegenerators’, J. Huazhong Univ. Sci. Technol., 2000, 28, (4), pp. 83–86.

19)

19. Xu, C.Q., Luo, R.J.: ‘Circulating current temperature rise and transposition way of the stator bars of large hydrogenerator’, Large Electr. Mach. Hydraulic Turbine, 1985, 1985, (2), pp. 1–2.

20)

20. Liang, Y.P., Bian, X., Yu, H.H., Wu, L., Yang, L.C.: ‘Analytic algorithm for strand slot leakage reactance of transposition bar in AC machine’, IEEE Trans. Ind. Electron., 2014, 61, (10), pp. 5232–5240 (doi: 10.1109/TIE.2014.2304922).
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