基于二阶同步提取变换的次同步振荡参数辨识

Identification of Sub-synchronous Oscillation Parameter Based on Second-order Synchronous Extracting Transform

针对电力系统频发的次同步振荡现象,以及因为振荡频率接近在参数辨识中造成的误差,文章提出一种适用于次同步振荡参数辨识的二阶同步提取变换和希尔伯特变换结合的方法。首先使用二阶同步提取变换方法对信号进行时频分析,得到信号时频图,然后用二阶同步提取变换逆变换分解重构出各个模态分量,最后用希尔伯特变换对提取出来的单个模态分量进行参数辨识,识别其频率、阻尼比、衰减因子等主要参数。分别用理想测试信号与录波数据对其进行验证,仿真结果表明,对比短时傅里叶变换等方法,该方法在计算各模态频率,模态分量重构以及参数辨识上有更高的精度。

In view of the sub-synchronous oscillation which is frequently occurs in the power system as well as the error caused in the parameter identification due to the proximity of oscillation frequency,a kind of method combining of second-order synchronous extracting transform with Hilbert transform for identification of sub-synchronous oscillation is proposed in the paper.-Firstly,the time-frequency analysis of the signal is performed by using the synchronous extraction transformation method to obtain time frequency diagram of the signal.Then,each modal component is reconstructed by the second order synchronous extraction and inverse transformation decomposition.Finally,the Hilbert transform is used for parameter identification of the extracted single modal components so to identify such parameters as frequency,damping ratio and attenuation factor.They are verified by the ideal test signal and recording data respectively.The simulation results show that this method,compared short-time Fourier transform etc,has higher accuracy in the calculation of each modal frequency,reconstruction of modal component and parameter identification.