一种多频振荡场景下的失稳模式划分方法

Classification of Unstable Modes Under Multi-frequency Oscillation

将多机系统在大扰动下的运动划分为机群间的相对运动和机群内各机组间的相对运动,据此将全系统的暂态能量分解为群间暂态能量和群内暂态能量。通过分析原系统群间暂态能量的变化规律并根据能量壁垒准则得到原系统的失稳时间tm;通过分析子系统群间暂态能量的变化规律得到子系统的临界解列时间tn;通过比较tm和tn与故障清除时间tc之间的关系将多频场景下的失稳模式划分为相继两群失稳、严格多群失稳及不严格多群失稳3种模式。此外,还针对不同的失稳模式给出了相应的解列方法,对多频场景下的解列策略具有一定的指导意义。最后,通过实际电网模型对以上分析结果进行了仿真验证。

Since the motion of the multi machine system under large disturbance can be divided into relative motion between clusters and relative motion in clusters, the concept of transient energy between clusters and transient energy within clusters can be put forward. The out-of-step time tm can be acquired based on the characteristics of transient energy between clusters of the original system and complementary-cluster energy-barrier criterion. By analyzing the characteristics of the transient energy between clusters of subsystem, the critical clearing time tn can be acquired. The unstable modes can be classified as successive- unstable mode, strict multi-group mode and inexact multi-group mode by comparing the duration of tm, tn and tc （fault clearing time）. Besides, splitting strategies are also provided for different instability modes, which have guiding significance for the splitting strategy under multi-frequency oscillation. The correctness of the foregoing analysis has been proved through simulation verification of an actual power grid model.