Zhejiang dianli (Nov 2024)

A rotational speed recovery strategy for wind turbines considering secondary frequency drops

  • LYU Zhenhua,
  • LI Yaran,
  • ZHENG Mingzhong,
  • LI Qiang,
  • HU Yingjie

DOI
https://doi.org/10.19585/j.zjdl.202411004
Journal volume & issue
Vol. 43, no. 11
pp. 26 – 35

Abstract

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Wind turbines can contribute to frequency regulation by releasing rotor kinetic energy, which is an effective way to ensure frequency stability in power systems with high wind power penetration. However, the rotor speed recovery process may cause a secondary frequency drop (SFD) in the system. To address this issue, a wind turbine speed recovery strategy based on the asymptotic characteristics of an exponential function is proposed, following both qualitative and quantitative analysis of the frequency support and speed recovery. First, during the recovery period, the rotor speed is restored according to the power reference value defined by an exponential function. After the speed is recovered, the control switches to maximum power point tracking (MPPT) to manage the turbine's output power. Second, the parameters of the exponential decay coefficient are tuned based on various constraints. Finally, simulation results validate that the proposed strategy effectively mitigates SFDs while ensuring a smooth rotor speed recovery process.

Keywords