基于无功出力调整的双馈风电场次同步振荡抑制策略研究

Research on Suppression Strategy of DFIG Wind Farm Based on Reactive Power Regulation for SSO

含串联电容补偿的风电外送系统存在着发生次同步振荡的风险,为降低次同步振荡风险,提出一种基于DFIG风电场整体无功出力调整的抑制次同步振荡方法。以华北某风电场为研究背景,研究了在多种运行下,风电场无功出力对次同步振荡的一般影响规律,研究表明,风电场发出感性无功总是对次同步振荡起到抑制作用。基于该规律制定了基于无功出力调整的双馈风电场控制策略,引入基于紧缩技术近似投影子空间跟踪(projection approximation subspace tracking based on the deflation technique,PASTd)的谱估计算法在线检测次同步振荡稳定性,当次同步振荡模式不稳定时,逐渐增大风电场无功出力,以降低次同步振荡风险。仿真结果表明,在多种运行状态下,该控制策略均能起到较好的抑制效果。

Since subsynchronous oscillation （SSO） may exist in the wind power delivery system with series-capaci- tor compensation. To reduce the risk of SSO, an SSO mitigation method based on adjusting the reactive power output of DFIG-based wind farm is proposed in this paper. Taking a certain wind farm in North China as the research background, the general rule for the influence of the reactive power output of wind farms on SSO under various operating conditions is studied, which shows that the inductive reactive power provided by the wind farm always suppresses subsynchronous oscillation. Based on this rule, a control strategy for reactive power adjustment of the DFIG-based wind farm is developed： the spectral estimation algorithm of projection approximation subspace tracking based on the deflation technique （PASTd） is introduced to detect the stability of SSO online, and when the SSO mode is unstable, the reactive power output of the wind farm will be gradually increased to reduce the risk of SSO. The simulation results show that under various operating conditions, the control strategy can always have a good suppression effect.