基于NExT和PRCE方法的低频振荡分析

Estimation of Electromechanical Oscillation Modes Based on NExT-PRCE Method

将结构学用于分析机械结构振动特性的多参考点复指数法(PRCE)与自然激励技术(NEx T)相结合实现基于随机响应的低频振荡模式辨识。该方法首先利用NEx T从系统随机响应信号中获得自由振荡信号,然后采用PRCE方法对所获得的自由振荡信号进行模式辨识得到低频振荡模式的频率、阻尼比和振荡模态。16机系统中基于蒙特卡洛仿真辨识结果表明了该方法的有效性和正确性;与已有方法的对比表明该方法在辨识精度以及抗噪性方面表现得更好。基于四川电网PMU实测数据的辨识结果表明了该方法的有效性和可行性,为电力系统低频振荡分析提供了一种途径和方法。

This paper investigates the use of the natural excitation technique （NExT） in conjunction with the multi reference poly-reference complex exponential （PRCE） for the modal analysis of power systems based on the ambient data. The PRCE method was formerly applied to analyze the vibration characteristics of mechanism structures. The NexT-PRCE method contain two steps the ring-down signals is extracted from ambient data by the NExT method, then the mode parameters are estimated by the PRCE algorithm form the ring-down signals. Estimated results based on Monte Carlo simulations on the 16 machine power system model show that the NExT-PRCE method can effectively identify the frequency, damping ratio and mode shape. The comparisons with other existed methods that the results estimated by the NExT-PRCE method is more accurate and the proposed method performance better with the measurement noise. The analysis based on the measured data from Sichuan power grid indicates the feasibility and validity of the new method proposed in this paper. It also provides a new way for power system stability analysis.