一种利用机端电压幅值轨迹MLE指标的暂态功角稳定在线辨识方法

An Online Identification Method for Transient Angle Stability Using MLE Index of Generator Terminal Voltage Amplitude Trajectory

在实时获取电网动态响应信息的基础上,为更有效地评估系统的暂态稳定性,文中从动态系统最大李雅普诺夫指数(maximum Lyapunov exponent,MLE)定义及其稳定分析机理出发,提出一种数据驱动的暂态功角稳定在线辨识方法。方法首先基于相空间重构理论、暂态功角稳定与机端节点电压幅值变化率-电压幅值偏差(Vmagcr-?Vmag)特性曲线的关系,将暂态功角稳定问题转变为受扰严重机组端节点?Vmag曲线的MLE轨迹分析问题;进而,利用递推最小二乘算法对MLE计算进行改进,并提出相关参数选取方法;最终,结合MLE曲线,给出了系统暂态稳定性的判断依据。方法无需对系统进行等值、简化及同调机组辨识,并克服了现有基于MLE暂态功角稳定评估方法需要预设MLE符号观测窗口的缺陷,具有较强的通用性与实用性。仿真算例验证了方法的正确性与有效性。

To assess the transient stability more effectively based on the real-time dynamic response information of the power grid, a data-driven online transient angle stability identification method was proposed in this paper based on the definition of maximum Lyapunov exponent （MLE） and its stability analysis ＇mechanism. Firstly, transient angle stability analysis problem was decomposed into MLE analysis problems of terminal voltage deviation curves of the severely disturbed generators based on phase space reconstruction and the relation between transient angle stability and characteristic curves of the change rate of voltage vs. voltage deviation （Vmagcr-△Vmag）. Then, a recursive least square （RLS） based on MLE calculation model and its relevant parameter selection method was proposed. Finally, the rule of transient angle stability detection based on the MLE curves was provided and in the approach the system equivalent, simplify and homology units identification are not needed. Meanwhile, the shortcoming of setting up MLE sign observation window in advance has been overcome, which makes the approach more universal and practical. The simulation results have verified the correctness and effectiveness of the proposed method.