风电并网系统次同步振荡的频域模式分析

Frequency Domain Modal Analysis of Subsynchronous Oscillation in Grid-connected Wind Power System

随着风电等新能源渗透率的提高,大量电力电子设备接入电力系统,电力电子变流器与大电网间的相互作用引发了多起新型次同步振荡事故。为了深入研究风电并网系统的振荡特性,文中提出了频域模式分析法。首先,建立目标系统的阻抗网络模型,并形成网络的节点导纳矩阵和回路阻抗矩阵。然后,通过求解矩阵行列式零点获得系统的振荡模式。接着,定义了节点(支路)的参与因子、可观度和可控度,并基于阻抗网络模型推导出了这些指标的计算公式,进而得到振荡路径和扰动源的信息。最后,将所提方法应用到实际风电并网系统中,通过仿真验证了方法的有效性。

With the increasing penetration of renewable energy sources such as wind power,a large number of power electronic devices are connected to the power system.The interaction between the power electronic converter and the bulk power grid has caused many new subsynchronous oscillation accidents.In order to deeply study the oscillation characteristics of grid-connected wind power system,this paper proposes a frequency domain modal analysis method.Firstly,the impedance network model(INM)of the target system is built,and the nodal admittance matrix and loop impedance matrix of the network are obtained.Secondly,the oscillation modes of the system are obtained by finding the zeros of the determinant of matrices.Thirdly,the nodal(branch)participation factors,observability and controllability for each oscillation mode are defined and the INM-based formulae are derived so as to identify the oscillation path and disturbance source.Finally,the proposed method is applied to the actual grid-connected wind power system,and the effectiveness of the method is verified by simulation.