含直驱风电机组的电力系统次同步振荡鲁棒阻尼控制
Robust Damping Control of Subsynchronous Oscillation in Power System with Direct-drive Wind Turbines
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摘要: 风电功率波动会导致电力系统运行点变化,为有效提高次同步振荡阻尼控制的适应性,文中采用直驱风电机组附加控制的方法设计了一种次同步振荡鲁棒阻尼控制器。首先,基于状态空间模型利用含区域极点配置的混合H2/H∞控制方法抑制由随机扰动引起的电力系统次同步振荡。将不同运行点作为凸多面体的顶点构建凸多面体模型,以适应风电输出波动引起的系统运行点大范围变化,提高控制器的鲁棒性。然后,利用线性矩阵不等式求解状态反馈矩阵,设计次同步振荡鲁棒阻尼控制器。最后,利用接入2台直驱风电机组的4机2区系统作为测试系统进行时域仿真。仿真结果表明,基于凸多面体的鲁棒阻尼控制器不仅能够为系统次同步振荡模式提供足够的阻尼,并且在风电功率在较大范围内变化的情况下,控制器也具有较好的控制效果。Abstract: The fluctuation of wind power may lead to the change of operation point in power system. In order to effectively improve the adaptability of subsynchronous oscillation damping control, a subsynchronous oscillation robust damping controller is designed by using the additional control method of direct-drive wind turbines. Firstly, based on the linearized state space model, the mixed H2/H∞control with regional pole placement is used to suppress the power system subsynchronous oscillation caused by random disturbance. The convex polytope model is constructed by using different operation points as the vertices of the convex polytope to adapt to the wide variation of system operation points caused by wind power output fluctuations and improve the robustness of the controller. Secondly, a linear matrix inequality is applied to solve the state feedback matrix and design a subsynchronous oscillation robust damping controller. Finally, a four-machine two-area system with two direct-drive wind turbines is used as the test system for time domain simulation. The simulation results show that the robust damping controller based on convex polytope can provide sufficient damping for the subsynchronous oscillation modes, and the controller also has good control effect when the outputs of wind power change over a wide range.