DFIG风电机组协同SVG抑制电网低频振荡方法

随着风电渗透率的日益增加，电力系统阻尼不足时易发生低频振荡，双馈风电机组（DFIG）可解耦控制有无功和无功输出，有利于增强系统阻尼。提出一种DFIG协同静止无功发生器（SVG）并网的方法，采用附加阻尼的控制策略，接入控制系统的功率控制节点，改变参考装置的有功和无功参考电流，实现装置动态输出功率，抵消功率增量，对系统中产生的功率振荡进行抑制。搭建DFIG协同SVG并网的4机2区域系统的控制系统模型，添加附加阻尼控制信号，控制DFIG输出的有功功率和SVG输出的无功功率，改变系统的特征根，并基于Prony方法分析振荡信号各模态。结果表明：该方法能够有效提供正阻尼，抑制系统低频振荡，加速振荡波形平息，提高电力系统的小干扰稳定性。

Method of DFIG Cooperating with SVG to Suppress Low-Frequency Oscillation in Power Systems

With the increasing penetration of wind power, when the power system is insufficiently damped, low-frequency oscillations are likely to occur. Doubly fed induction generation (DFIG) can decouple the control of active and reactive power, which helps enhance system damping. This paper proposes a method for grid connection of DFIG units with static var generator (SVG). It adopts a control strategy of additional damping, accesses the power control node of the control system, changes the active and reactive reference current of the device, and realizes the dynamic output power of the device to offset the power increase to suppress the power oscillations in the system. The control system model of DFIG and SVG connected to 4-machine 2-area system is built. Additional damping control signals are added to control the active power of DFIG and the reactive power of SVG. The characteristic root of the system is changed, and the modalities of the oscillating signals are analyzed based on Prony method. The results show that the method can effectively provide positive damping, suppress low-frequency oscillation of the system, accelerate the stabilization of oscillation waveform and improve the small signal stability of the power system.