基于定子侧模拟电阻的双馈风电场次同步振荡抑制策略研究

双馈风电场并网运行时,容易发生次同步振荡事故。搭建了双馈风电场经串联补偿电容并网的系统模型,并用Nyquist稳定性判据分析了影响双馈风电场次同步振荡的主要因素。在此基础上,提出了一种基于定子侧模拟电阻的次同步振荡抑制策略,以增强次同步频带下的电气阻尼。时域仿真结果表明该方法能够有效抑制双馈风电场并网系统中的次同步振荡现象,提升系统的稳定性。相较于传统的抑制方法,所提方案无需任何附加装置,便于工程实际应用。

Analysis of a new control strategy based on stator-side virtual resistance to suppress sub-synchronous oscillation in DFIG-based wind farms

When connected to the grid, sub-synchronous oscillations may occur in the wind farms composed of Doubly-Fed Induction Generators (DFIG). This paper builds the system model of the DFIG-based wind farms that are connected to the grid via series compensation capacitors, and then analyses the main factors that affect the characteristics of the sub-synchronous oscillations with the Nyquist stability criterion. On this basis, a new control strategy based on stator-side virtual resistance is proposed to suppress the sub-synchronous oscillation by enhancing the electrical damping within the sub-synchronous frequency band. The simulation results in time domain show that this method can effectively suppress the occurrence of sub-synchronous oscillation and improve the stability of the system. Compared with the traditional suppressing method, the new strategy in this paper does not need any additional devices, thus it is favorable for engineering applications. This work is supported by National Natural Science Foundation of China (No. 51707096) and Open Fund Project of Jiangsu Wind Power Engineering Technology Center (No. ZK16-03-02).