针对故障后系统的区间振荡，提出改进的单机等效法分析不同区域间的相互作用，并制定相应的控制措施。根据故障后各发电机功角的振荡轨迹，将系统划分为若干个主导振荡区域和非主导振荡区域，并将多区域系统进一步等效为单机无穷大母线(one machine infinite bus，OMIB)系统。定义并计算不同区域间的相对动能及OMIB系统动能，用于分析不同区域间的非线性相互作用。采用傅里叶频谱分析和Prony分析辨识OMIB系统参数，得到故障后系统的主导振荡模式及相应的阻尼比。基于上述分析，提出调整故障前各区域发电机出力的方法以减少区间的相对动能，抑制互联区域振荡。算法用于分析和控制IEEE5区域16机标准测试系统的故障后区间振荡。仿真结果表明，算法不但能准确辨识故障后的主导振荡模式，且能分析多种区间模式的非线性相互作用；控制措施显著地提升了系统阻尼，抑制了故障后系统的区间低频振荡。

The paper proposed a multi-area single machine equivalent method to analyze interaction among different power system areas and corresponding control measure to provide good damping torque to post-fault inter-area oscillations. The method divided a multi-machine system into critical areas and non-critical areas according to all the generator power angle swing trajectories and then further reduced them into equivalent one machine infinite bus (OMIB) systems. Relative kinetic energy between different areas and OMIB system kinetic energy was defined and calculated to analyze non-linear inter-area interaction. Fourier frequency spectrum analysis and Prony analysis were used to find dominant modes of power oscillations and their damping ratios. According to the analysis above, the paper proposed a pre-fault control measure of rescheduling power generation among different areas to reduce power system kinetic energy and improve power system damping. The proposed method and control measure were used to analyze and control inter-area oscillations of IEEE five-area-sixteen-machine benchmark system. Test results show that the method can correctly identify post-fault dominant oscillation modes and effectively analyze non-linear interaction among various inter-area modes; the control measure well damps post-fault inter-area low frequency oscillations.

国家“十一五”重点科技攻关计划项目(2006BAA02A17)。