风电场根据并网导则在低电压穿越期间向系统注入无功电流可能引起风电系统失稳，导致风电场低电压穿越失败。针对该问题，建立了该运行工况下含有锁相环环节的风电系统状态空间模型，有效揭示了系统失稳的原因，提出了利用储能装置改善风电场注入电流特性进而维持系统稳定的措施。仿真结果表明：所提风电系统低电压运行工况下的状态方程能够有效地描述系统的小扰动稳定特性；储能装置通过合理注入有功电流改善了风电场注入电流特性，有效提高了风电场低电压情况下的系统稳定性。%According to the grid codes, wind farms must inject reactive power current into power grid during the low voltage ride-through (LVRT) process. This would lead to instability of the wind power system and the LVRT failure of wind farm. A state space model of wind power system including the phase locked loop at the low voltage state was established in this paper, to analyze the instability phenomenon. Then the reasons of the instability phenomenon were well revealed. Finally, a stability control strategy was proposed to improve the stability of the wind power system by utilizing the energy storage system. Simulation results show that the state model of the wind power system at low voltage state can represent the small disturbance stability characteristic of the system. The energy storage system could effectively improve the injection current feature of wind power system and accordingly improve the system stability.
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