Improved Frequency Mitigation of a Variable-Speed Wind Turbine

개선된 가변속 풍력발전기의 주파수 평활화

  • Li, Mingguang (Dept. of Electrical Engineering, Chonbuk National University) ;
  • Yang, Dejian (Dept. of Electrical Engineering, Chonbuk National University) ;
  • Kang, Yong Cheol (Dept. of Energy IT, Gachon University) ;
  • Hong, Junhee (Dept. of Energy IT, Gachon University)
  • Received : 2018.03.08
  • Accepted : 2018.05.15
  • Published : 2018.06.01


For a power grid that has a high wind penetration level, when wind speeds are continuously fluctuating, the maximum power point tracking (MPPT) operation of a variable-speed wind turbine (VSWT) causes the significant output power fluctuation of a VSWT, thereby significantly fluctuating the system frequency. In this paper, an improved power-smoothing scheme of a VSWT is presented that significantly mitigates the frequency fluctuation caused by varying wind speeds. The proposed scheme employs an additional control loop based on the frequency deviation that operates in combination with the MPPT control loop. To improve the power-smoothing capability of a VSWT in the over-frequency section (OFS), the control gain of the additional loop, which is set to be inversely proportional to the rotor speed, is proposed. In contrast, the control gain in the under-frequency section is set to be proportional to the rotor speed to improve the power-smoothing capability while avoiding over-deceleration of the rotor speed of a VSWT. The proposed scheme significantly improves the performance of the power-smoothing capability in the OFS, thereby smoothing the frequency fluctuation. The results clearly demonstrate that the proposed scheme significantly mitigates the frequency fluctuation by employing the different control gain for the OFS under various wind penetration scenarios.


Supported by : Korea Institute of Energy Technology Evaluation and Planning(KETEP)


  1. H. Bevrani, Robust Power System Frequency Control, 2nd ed. New York: Springer, 2014.
  2. G. Lalor, A. Mullane, and M. O'Malley, "Frequency control and wind turbine technologies," IEEE Trans. Power Syst., vol. 20, no. 4, pp. 1905-1913, Nov. 2005.
  3. E. Fagan, S. Grimes, J. McArdle, P. Smith, and M. Stronge, "Grid code provisions for wind generators in Ireland," in Proc. 2005 IEEE PES General Meeting, vol. 2, San Francisco, California, pp. 1241-1247.
  4. EirGrid, "Controllable wind farm power station grid code provisions, EirGrid (Ireland) Grid Code," ver. 3.1, 2008.
  5. F. Diaz-Gonzalez, F. D. Bianchi, A. Sumper, and O. Gomis-Bellmunt, "Control of a flywheel energy storage system for power smoothing in wind power plants," IEEE Trans. Energy Convers., vol. 29, no. 1, pp. 204-214, Mar. 2014.
  6. J. Pegueroles-Queralt, F. D. Bianchi, and O. Gomis-Bellmunt, "A power smoothing system based on supercapacitors for renewable distributed generation," IEEE Trans. Ind. Electron., vol. 62, no. 1, pp. 343-350, Jan. 2015.
  7. X. Li, D. Hui, and X. Lai, "Battery energy storage station (BESS)-based smoothing control of photovoltaic (PV) and wind power generation fluctuations," IEEE Trans. Sustain. Energy, vol. 4, no. 2, pp. 464-473, Apr. 2013.
  8. I. D. Margaris, S. A. Papathanassiou, N. D. Hatziargyriou, A. D. Hansen, and P. Sorensen, "Frequency control in autonomous power systems with high wind power penetration," IEEE Trans. Sustain. Energy, vol. 3, no. 2, pp. 189-199, Apr. 2012.
  9. M. Wang-hansen, R. Josefsson, and H. Mehmendovic, "Frequency controlling wind power modeling of control strategies," IEEE Trans. Sustain. Energy, vol. 4, no. 4, pp. 954-959, Oct. 2013.
  10. Y. Kim, M. Kang, E. Muljadi, J.-W. Park, and Y. C. Kang, "Power smoothing of a variable-speed wind turbine generator in association with the rotor speed-dependent gain," IEEE Trans. Sustain. Energy, vol. 8, no. 3, pp. 990-999, Jul. 2017.
  11. A. M. Howlader, N. Urasaki, A. Yona, T. Senjyu, and A. Y. Saber, "A review of output power smoothing methods for wind energy conversion systems," Renew. Sustain. Energy Rev., vol. 26, pp. 135-134, Oct. 2013.
  12. R. T. Byerly, O. Aanstad, D. H. Berry, R. D. Dunlop, D. N. Ewart, B. M. Fox, L. H. Johnson, and D. W. Tschappat, "Dynamic models for steam and hydro turbines in power system studies," IEEE Trans. Power App. Syst., vol. PAS-92, pp. 1904-1915, Nov. 1973.
  13. T. Ackermann, "Overview of Integration Studies-Methodologies and Results," in Wind Power in Power Systems, 2nd ed. England: John Wiley & Sons, Ltd., 2012.