access icon free Electrical braking of synchronous generators for combined generator and water turbine bearings as well as stray-load losses determination

© The Institution of Engineering and Technology
Received 20/02/2012, Accepted 08/02/2013, Revised 31/01/2013, Published

This study describes a new method for determining combined synchronous generator and water turbine bearings losses as well as stray-load losses of a generator, based on measurement of the speed change during electrical braking. In the electrical braking regime, the total braking torque of a hydrogenerator is made up of the torques defined by losses in the runner chamber of the hydraulic turbine, ventilation losses in the hydraulic-turbine generator, bearings losses in the generator and the water turbine, as well as electromagnetic and stray-load losses in the short-circuit. In this study, the torque–speed curve is represented by the corresponding equations which describe all the torques occurring during electrical braking. By applying these equations to the measured results and using some numerical calculations, combined generator and water turbine bearings losses as well as stray-load losses can be obtained. The proposed method is applied on a 190 MW generator at the Hydro Power Plant (HPP) Djerdap (in Serbia). The obtained results demonstrated a very high level of accuracy when compared with the values found in the manufacturer's technical documentation (Electrosila). The proposed method has the best and most economical use in large synchronous generators and generators in older power plants.

Inspec keywords: losses; torque; angular velocity measurement; synchronous generators; machine bearings; hydroelectric generators; braking; hydroelectric power stations

Other keywords: hydrogenerator; Djerdap; hydraulic turbine; stray-load losses determination; torque-speed curve; short-circuit; braking torque; electromagnetic losses; speed change measurement; stray-load losses; numerical calculations; manufacturer technical documentation; power 190 MW; hydraulic-turbine generator; water turbine bearings losses; older power plants; runner chamber; ventilation losses; electrical braking regime; HPP; combined synchronous generator; hydro power plant

Subjects: Hydroelectric power stations and plants; Velocity, acceleration and rotation measurement

References

    1. 1)
      • 11. Bertalanic, Z., Pavlica, M., Maljkovic, Z.: ‘Analysis of hydro-generator's losses determined by calorimetric method’. XIX Int. Conf. on Electrical Machines, (ICEM 2010), Rome, Italy, September 2010, pp. 1–6.
    2. 2)
      • 12. Johnson, J.A.: ‘Retardation method of loss determination’, Trans. Am. Inst. Electron. Eng., 1926, XLV, pp. 747–759 (doi: 10.1109/T-AIEE.1926.5061269).
    3. 3)
      • 1. Grigsby, L.L.: ‘The Electric Power Engineering Handbook’ (CRC Press in Cooperation with IEEE press, 2001, 1st edn.).
    4. 4)
      • 20. Soltani, J., Szabados, B., Hoolboom, J.: ‘A novel method of measurement of synchronous machine losses using synthetic loading’, IEEE Trans. Instrum. Meas., 2002, 51, (6), pp. 1228–1233 (doi: 10.1109/TIM.2002.808055).
    5. 5)
      • 26. Petrović, D., Stojković, S., Vidaković, V., et al: ‘Possibilities to increase power and efficiency of hidro generating unit’. CIGRE 2008, Paris, France, August 2008, vol. A1-105, pp. 1–8.
    6. 6)
      • 15. Calasan, M., Ostojic, M., Petrovic, D.: ‘The retardation method for bearings loss determination’. IEEE Int. Symp. on Power Electronics, Electrical Drives, Automation and Motion, (SPEEDAM 2012), Sorrento, Italy, June 2012, pp. 25–29.
    7. 7)
      • 17. Polard, E.I.: ‘Load losses in salient pole synchronous machines’, Trans. Am. Inst. Electron. Eng., 1935, 54, (12), pp. 1332–1340 (doi: 10.1109/T-AIEE.1935.5056928).
    8. 8)
      • 5. IEC 34-2A: ‘Measuring the losses using the calorimetric method’, 1974.
    9. 9)
      • 8. Rasilo, P., Ekstrom, J., Haavisto, A., Belahcen, A., Arkkio, A.: ‘Calorimetric system for measurement of synchronous machine losses’, IET Electr. Power Appl., 2012, 6, (5), pp. 286–294 (doi: 10.1049/iet-epa.2011.0241).
    10. 10)
      • 23. Hagemeister, E.A., Novikov, A.F., Filippov, A., Karpov, A.M.: ‘Experimental testing of Chirkeiskaya HPP hydrogenerators electrical braking’, Energetika, 1987, 7, pp. 47–49(in Russian).
    11. 11)
      • 4. IEEE Guide Std. 115-1995: ‘Test Procedures for Synchronous Machines’ 1995.
    12. 12)
      • 7. Preecha, P., Dejvises, J.: ‘The power losses calculation technique of electrical machines using the heat transfer theory’. Int. Power Engineering Conf., (IPEC 2007), Singapore, December 2007, pp. 297–301.
    13. 13)
      • 19. Traxler-Samek, G., Zickermann, R., Schwery, A.: ‘Cooling airflow, losses, and temperatures in large air-cooled synchronous machines’, IEEE Trans. Ind. Electron., 2012, 57, (1), pp. 172–180 (doi: 10.1109/TIE.2009.2031191).
    14. 14)
      • 13. Charlton, O.E., Ketchum, W.D.: ‘Determination of generator speed and retardation during loss measurements’, Trans. Am. Inst. Electron. Eng., 1930, 49, (3), pp. 1095–1100 (doi: 10.1109/T-AIEE.1930.5055625).
    15. 15)
      • 3. Paris, H.D., Guera, E.: ‘State of the art in efficiency of hydro generators’, Electra, 2011, 257, pp. 57–65.
    16. 16)
      • 25. Avrorov, A.B., Pinskii, G.B.: ‘Initial breaking speed of hydroelectric unit’, Hydrotech. Constr., 1997, 31, (12), pp. 729–732 (doi: 10.1007/BF02766229).
    17. 17)
      • 27. Kharab, A., Guenther, R.B.: ‘An introduction to numerical methods – a MATLAB approach’ (Chapman and Hall/CRC Press, 2011, 3rd edn.).
    18. 18)
      • 24. Novikov, A.F., Hagemeister, E.A.: ‘Electrical braking HPP and GPP aggregates’, Electrosila, 1991, 38, pp. 31–36(in Russian).
    19. 19)
      • 14. Zlatanovici, D., Dumitrescu, S., Bauer, A., Telivets, Y.: ‘Determination of hydroelectric generator efficiency by means of the retardation method’, J. Sust. Energy, 2011, II, (3), pp. 60–65.
    20. 20)
      • 21. Babau, R., Boldea, I., Miller, T.J.E., Muntean, N.: ‘Complete parameter identification of large induction machines from no-load acceleration–deceleration tests’, IEEE Trans. Ind. Electron., 2007, 54, (4), pp. 1962–1972 (doi: 10.1109/TIE.2007.895080).
    21. 21)
      • 10. Zlatanovici, D., Zlatanovici, R., Novac, D., Regli, M., Bogdanovici, S.: ‘Efficiency measurement by applying two different methods at the modernized hydrogenerators in Iron Gates I hydroelectric power plant’. CIGRE 2006, Paris, France, August 2006, vol. A1-210, pp. 1–9.
    22. 22)
      • 16. Karmaker, H.C.: ‘Stray losses in large synchronous machines’, IEEE Trans. Energy Convers., 1992, 7, (1), pp. 148–153 (doi: 10.1109/60.124554).
    23. 23)
      • 9. Szabados, B., Mihalcea, A.: ‘Design and implementation of a calorimetric measurement facility for determining losses in electrical machines’. IEEE Instrumentation and Measurement Technology Conf., Budapest, Hungary, May 2001, pp. 1785–1790.
    24. 24)
      • 22. Ilina, D.I.: ‘Experimental determination of moment to inertia and mechanical losses vs. speed, in electrical machines’. Proc. Seventh Int. Symp. on Advanced Topics in Electrical Engineering, Bucharest, Romania, May 2011, pp. 1–4.
    25. 25)
      • 18. Belahcen, A., Arkkio, A.: ‘Computation of additional losses due to rotor eccentricity in electrical machines’, IET Electron. Power Appl., 2010, 4, (4), pp. 259–266 (doi: 10.1049/iet-epa.2009.0139).
    26. 26)
      • 6. Boldea, I.: ‘Synchronous generators’ (CRC Press Taylor & Francis Group, 2006, 1st edn.).
    27. 27)
      • 2. Alhasawi, F.B., Milanovic, J.V.: ‘Ranking the importance of synchronous generators for renewable energy integration’, IEEE Trans. Power Syst., 2012, 27, (1), pp. 416–423 (doi: 10.1109/TPWRS.2011.2159250).
http://iet.metastore.ingenta.com/content/journals/10.1049/iet-epa.2012.0277
Loading

Related content

content/journals/10.1049/iet-epa.2012.0277
pub_keyword,iet_inspecKeyword,pub_concept
6
6
Loading