Electromechanical Energy Conversion Systems

Electromechanical Energy Conversion Systems

Review of End Winding Forces Estimation in Synchronous Generators

Document Type : Review Article

Authors
Mehdi Aliahmadi 1
Alireza Ghaempanah
Javad Faiz 2
1 Niroo Research Institute (NRI)
2 2Department of Electrical and Computer Engineering, University of Tehran, Tehran, Iran
10.30503/eecs.2023.376522.1030
Abstract
Increasing loading without comparable change in the size of synchronous generators, causes end-winding force estimation become important. Therefore, design of an appropriate support to protect windings deterioration and damages by the above mentioned forces is critical. In slot-embedded portion of coils, the forces could be adjusted by teeth and slot wedges. Normally, the ends of coils have no external support and it is necessary to provide it. Synchronous generators have been considered reliable if accurate end winding forces are evaluated and taken into account in the design process of the external support. The topic based on the current literature is reviewed. Structure of end windings and different analytical and numerical techniques for forces estimation are discussed. The current state of the art is reviewed and more successful developments are introduced. At the end, the area of research which needs more attention in the future to advance the subject is identified.
Keywords
Analytical methods
end winding
magnetic force estimation
synchronous generators
Subjects
  • Klempner, and I. Kerszenbaum, "Operation and Maintenance of Large Turbo-Generators," John Wiley & Sons Inc., 2004.
  • T. Holmberg, "Three Dimensional Finite Element Computation of Eddy Currents in Synchronous Machines," Technical report, No. 350, Chalmers University of Technology.
  • F. Calvert, "Forces in Turbine Generator Stator Windings," AIEE Trans., Vol. 50, pp.178-196, March 1931.
  • Harrington, "Forces in Machine End Windings," AIEE Trans.,Vol. 71, part III, pp. 849-859, October 1952.
  • Hammond, "Electric and Magnetic Images," Proc. Inst. Elec. Eng., Vol. 107c, Monograph No. 379, pp. 306-313, May 1960.
  • J. Carpenter, "The Application of the Method of Images to Machine End-Winding Fields," Proc. Inst. Elec. Eng., Vol. 107, No. 3327, pp. 487-500, October 1960.
  • B. Young, and D.H. Tompsett, "Short Circuit Forces on Turbo-generator End-Windings," Proc. Inst. Elec. Eng., Vol. 102, Part A, No. 2, pp. 101-119, April 1955.
  • T. Smith, "End Component of Armature Leakage Reactance of Round-Rotor Generators," AIEE Transactions, Part III (power apparatus and systems), Vol. 77, pp.636-647, August 1958.
  • Hammond, "The Calculation of Magnetic Field of Rotating Machines, Part 1: The Field of a Tabular Current," Proc. Inst. Elec. Eng., Vol. 106c, Monograph No. 333, pp. 158-164, May 1959.
  • S. Ashworth and P. Hammond, "The Calculation of the Magnetic Field of Rotating Machines, part 2.—The Field of Turbo-Generator End-Windings," Proc. Inst. Elec. Eng., Vol. 108A, No. 3489, pp. 527-538, March 1961.
  • A. Tegopoulos, "Determination or the Magnetic Field in the End Zone of Turbine Generators," IEEE Trans. on power apparatus and systems, Vol. 81, pp. 562-572, August 1963.
  • A. Tegopoulos, "Current Sheets Equivalent to End-Winding Currents of Turbine-Generator Stator and Rotor," AIEE Trans., Vol. 81, pp. 695-700, February 1963.
  • A. Tegopoulos, "Flux Impinging on the End Plate of Turbine Generators," AIEE Trans., Vol. 81, pp. 700-706, February 1963.
  • A. Tegopoulos, "Magnetic Vector Potential as a Result of Elementary Currents Between Two Parallel Planes," IEEE Trans. on power apparatus and systems, Vol. 81, pp. 559-562, August 1963.
  • A. Tegopoulos, "Forces on the End Winding of Turbine-Generators, I-Determination of Flux Densities," IEEE Trans. on power apparatus and systems, Vol. PAS-85, No. 2, pp. 105-113, February 1966.
  • A. Tegopoulos, "Forces on the End Winding of Turbine-Generators, II-Determination of Forces," IEEE Trans. on power apparatus and systems, Vol. PAS-85, No. 2, pp. 114-122, February 1966.
  • J. Lawrenson, "The Magnetic Field of the End-Windings of Turbo-Generators," Proc. Inst. Elec. Eng., Vol. 108A, No. 3490, pp. 538-549, March 1961.
  • J. Lawrenson, "Forces on Turbogenerator End Windings," Proc. Inst. Elec. Eng., Vol. 112, No. 6, pp. 1144-1158, June 1965.
  • B. Brandl, "Forces on the End Winding of AC Machines", Brown Boveri Review, Vol. 2, pp. 128-134, 1982.
  • Nitsche, "Fields and Forces in End-windings of Synchronous Machines at sudden short-circuits," Proceedings of International Conference on electrical Machines, pp. G3/5-1- G3/5-10, 1978.
  • C. Karmaker, "End Winding Fields and Forces in Salient-pole Synchronous Machines," Proceedings of International Conference on electrical Machines, Espoo, Finland, pp. 1139-1142, August 2000.
  • Merkhouf, B. F. Boueri, and H. Karmaker, "Generator End Winding and Natural Frequency Analysis," Proceedings of International Conference on Electric Machines and Drives, Madison, Wisconsin, USA , pp.111-114, June 2003.
  • Wen, R. Yao, and J. A. Tegopoulos, "Transient Quasi-3D Method in the Transient Electromagnetic Field Calculation of End Region of Turbo-generator," IEEE Trans. on Magnetics, Vol. 30, No. 5, pp. 3709-3712, Sept. 1994.
  • Wen, R. Yao, and J. A. Tegopoulos, "Calculation of Forces on the Stator End Winding of Turbogenerator by the Transient Quasi-3D Method," IEEE Trans. on Magnetics, Vol. 32, pp. 1669-1672, May 1996.
  • Freese, and A. Gruning, "Influence of the Rotor Retaining Ring on the Electromagnetic Forces in the End Winding of a Turbogenerator," 21th Symposium on Electromagnetic Phenomena in nonlinear circuits, Dortmund and Essen, Germany, 2010.
  • Senske, S. Kulig, J. Hauhoff, and D. Wunsch, "Vibrational Behavior of the Turbogenerator Stator End Winding in Case of Electrical Failures," Conf. Proc. CIGRE, Yokohama, Japan, 29 October 1997.
  • Drubel, S. Kulig, and K. Senske, "End Winding Deformations in Different Turbo generators during 3-phase short circuit and full load operation," Electrical Engineering, Vol. 82, pp. 145-152, Springer-Verlag 2000.
  • Gruning, and S. Kulig, "Electromagnetic Forces and Mechanical Oscillations of the Stator End Winding of Turbo Generators," Springer-Verlag, pp. 115-126, 2006.
  • R. Davey, "A Three Dimensional Scalar Potential Field Solution and its Application to the Turbine Generator End Region," IEEE Transactions on Power Apparatus and Systems, Vol. PAS-100, No. 5, pp. 2302-2310, May 1981.
  • J. Scott, S. J. Salon, and G. L. Kusik, "Electromagnetic Forces on the Armature End Windings of Large Turbine Generators, I. steady states conditions," IEEE Trans. PAS, Vol. PAS-100, No. 1, pp.4597-4603, Nov. 1981.
  • J. Salon, D. J. Scott, and G. L. Kusik, "Electromagnetic Forces on the End Windings of Large Turbine Generators, II. Transient Conditions," IEEE Transactions on Power Apparatus and Systems, Vol. PAS-102, No. 1, pp. 14-19, January 1983.
  • K.M. Khan, G.W. Buckley, and N. Brooks, "Calculation of Forces and Stresses on Generator End-Windings - Part I: Force," IEEE Trans. on Energy Conversion, Vol. 4, No. 4, pp. 661-670, December 1989.
  • K. Chow, Y. T. Lee, and E. A. Owen, "An Integral-Equation/Singularity-Method Approach for 3-D Electromagnetic Field determination in the End Region of a Turbine-Generator," IEEE Transactions on Magnetics, Vol. MAG-18, No. 2, pp. 340-345, March 1982.
  • Frei-Spreiter, and K. Reichert, "Calculation of End Winding Field of Turbogenerators by Integral Methods for Modeling Mechanical Characteristics," IEEE Trans. on Magnetics, Vol. 34, No. 5, pp. 3636-3639, September 1998.
  • Richard, F. Dufeau, A. C. Leger and N. Szylowicz, "Computation of Forces and Stresses on Generator End Windings Using a 3D Finite Element Method," IEEE Trans. on Magnetics, Vol. 32, No. 3, pp. 1689-1692, May 1996.
  • Richard, "Calculation of electromagnetic forces on large generator end-windings under fault conditions using a three-dimensional finite element method," Elsevier, Mathematics and Computers in Simulation, 46, pp. 257-263, 1998.
  • Richard, J.P. Ducreux, and A. Foggia, "A Three Dimensional Finite Element Analysis of the Magnetic Field in the End Region of a Synchronous Generator," Proceedings of International Conference on Electric Machines and Drives, Milwaukee, Wisconsin, USA, pp. wc2-4.1-wc2-4.3, May 1997.  
  • Stermecki, O. Biro, H. Lang, G. Ofner, K. Preis, and S Rainer, "Analysis of Synchronous Generator End-Winding Deformations Using 3-D Time-Harmonic FEM, " Proceedings of International Conference on Electrical Machines, Rome, Italy, Sep. 2010.
  • Yujing Liu, and S. Hjärne, "Analysis of Forces on Coil Ends of Formed Stator Windings," Proceeding of International Conference on Electrical Machines and Systems, Seoul, South Korea, pp. 1019-1024, October 2007.
  • D. Stancheva, and I. I. Iatcheva, "3-D Electromagnetic Force Distribution in the End Region of Turbogenerator", IEEE Transactions on Magnetics, Vol. 45, No. 3, pp. 1000-1003, March 2009.

Z. Chong, H. Song, and Y. Yongming, “Analysis of electromagnetic forces on involute part of end winding in a 1550 MW nuclear generator”, Proceedings of 2nd Advanced Information Technology, Electronic and Automation Control Conference, Chongqing, China, October, 2017

Electromechanical Energy Conversion Systems
Volume 2, Issue 1
Winter 2023
Pages 9-28

  • Receive Date 13 December 2022
  • Revise Date 25 January 2023
  • Accept Date 31 January 2023