To avoid the secondary frequency dip caused by the steep drop of the electrical power of wind turbines (WTs) at the end of frequency support stage, the torque limit-based iner-tial control (TLIC) method sets the power reference as a linear function of rotor speed, rather than the step form for the step-wise inertial control. However, the compensation effect on the frequency nadir (FN) caused by the load surge is weakened as the TLIC power is no longer in the step form. Specifically, the maximum point of the frequency response component (FRC) contributed by TLIC occurs earlier than the minimum point of FRC corresponding to the load surge, so that the FN cannot be adequately raised. Therefore, this paper first investigates the relation between the peak and nadir times of FRCs stimulated by the TLIC and load power. On this basis, with the compensation principle of matching the peak and nadir times of FRCs, the improved TLIC method based on delayed support is proposed. Finally, the effectiveness of the proposed method is validated via the experiments on the test bench of wind-integrated power system.

中文翻译：

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基于延迟支持的扭矩极限惯性控制方法用于风电机组一次频率控制

为了避免频率支持阶段结束时风电机组电功率急剧下降引起的二次频率跌落，基于扭矩限制的惯性控制（TLIC）方法将功率参考设置为线性函数转子速度，而不是步进惯性控制的步进形式。然而，由于TLIC功率不再呈阶跃形式，对负载浪涌引起的频率最低点（FN）的补偿效果减弱。具体地，由TLIC贡献的频率响应分量(FRC)的最大点早于对应于负载浪涌的FRC的最小点出现，使得FN不能充分提高。因此，本文首先研究了TLIC刺激的FRC的峰值和最低点时间与负载功率之间的关系。在此基础上，根据FRC峰谷时间匹配的补偿原理，提出了基于延迟支持的改进TLIC方法。最后通过风电并网系统试验台上的实验验证了所提方法的有效性。