计及网络谐振结构的双馈风电场次同步振荡问题分析及抑制

Analysis and suppression on sub-synchronous oscillation problems of DFIWG-based wind farm considering network resonance structure

针对双馈风电场经串补送出时的振荡问题,致力于从电力网络谐振的角度分析其振荡机理,并提出相关抑制措施。首先结合双馈风机的基本结构,对其交流侧受扰动时的响应特性进行了分析,建立起双馈风机的端口阻抗模型。在此基础上,采用s域节点导纳矩阵法分析了不同运行工况下双馈风电场经串补送出系统的网络谐振结构,并确定了不稳定谐振模式的主要影响区域。最后,针对最不稳定的谐振模式提出了基于旁路阻尼滤波器的谐振抑制措施,并通过电磁暂态仿真对其有效性进行了验证。算例分析表明,在高串补度、低运行转速下,系统在次同步频段内确实存在一定的谐振风险;通过合理设计旁路阻尼滤波器参数,可以有效提高系统的谐振稳定性。

For the oscillation problem in the DFIWG(Doubly-Fed Induction Wind Generator)-based wind farm transmitted by series-compensated line,the oscillation mechanism and its relevant suppression strategy are investigated from the view of electrical network resonance.Firstly,based on the basic structure of the DFIWG,the AC-side disturbance characteristics is analyzed to establish its port-impedance model.On the basis,for the DFIWG-based series-compensated transmission system,the electrical network resonance structures under different operation situations are investigated by s-domain nodal admittance matrix method.The main influencing area of the unstable resonance mode is also determined.Finally,for the most unstable resonance mode,the BDF(Bypass Damping Filter)-based resonance suppression strategy is proposed and verified by electro-magnetic transient simulation.Case studies indicate that there exists certain resonance instability risk under higher series-compensated extent and lower operation rotating speed.In addition,the system resonance stability can be highly improved by designing the BDF parameters properly.