受扰轨迹上动态鞍点的病态及其识别

Trajectory Characteristic Based Identification of Ill-conditioned DSP in EEAC

受扰轨迹上出现动态鞍点(DSP),不仅是扩展等面积准则(EEAC)判断电力系统暂态失稳的定性判据,也是系统失稳程度的量化观察点。然而,映像系统的强时变性可能造成其轨迹上出现一些虽然符合DSP的定义,却不能精确量化失稳程度的点。若不能可靠地识别出这些病态的DSP(IDSP),就无法在工程应用中通过提前终止数值积分来减少计算量。研究表明,在IDSP处,映像系统不但时变因素较强,并且存在潜在的势能。据此,提出DSP的病态特征指标及IDSP的识别方法,并通过对新英格兰系统的大量仿真,验证了其有效性。此项研究有助于对多刚体运动稳定性机理的深入理解。

In extended equal area criterion （EEAC）, dynamic saddle points （DSP） encountered in disturbed trajectories can be regarded as not only the criterion of power system instability, but also the observation point for the quantitative analysis of stability degree. However, the strong time-varying of image systems might result in some special trajectory points, which although satisfy the definition of DSP, are not suitable for accurately assessing the stability degree. If the above ill-conditioned DSPs （IDSPs） can be distinguished, the computational burdens can be further reduced in the engineering application via early termination of the integration process. The studies show that around IDSPs, image systems not only exhibit the strong timevarying characteristic, but also exist the potential energy. With this knowledge, an ill-condition index of DSP and the corresponding identification method for IDSP are proposed. They are thoroughly verified in the New England system. This research also contributes to the study on stability mechanisms of general nonlinear dynamic systems.