检测低频振荡模式的EMD复合算法研究

提出一种抗模态混叠的EMD复合算法。首先,通过改进频率外差方法,增加混叠模态分量间的频谱距离,有效分离出倍频模态混叠成分;其次,结合小波奇异点检测技术,确定各模态分量的自适应滑动分析窗口,实现间歇性混叠模态分离和振荡模式非平稳参数辨识。为验证算法的有效性,利用测试算例和电网仿真算例进行了测试分析,结果表明,该算法能够有效分离出混叠模式分量,对于模式复杂的低频振荡信号,能够有效分离出对应的低频振荡模式,具有较高的振荡模式信息检测精度。

Research on EMD Composite Algorithm for Detecting the Low Frequency Oscillations Modes

In this paper, an anti mode mixing empirical mode decomposition (EMD) composite algorithm is proposed. First, the improved frequency heterodyne method is addressed to increase the spectral distance between mode mixing components in order to isolate the octave mode mixing components. Second, the wavelet singularity detection technology is applied to determine the adaptive sliding analysis window for each mode and then implement the intermittent mixing modes separation and their nonstationary parameters identification. In order to verify the validity of the algorithm, a test case and a grid simulation case are used to test and analyze the EMD composite algorithm. The analysis result shows that the proposed algorithm can isolate the mode mixing component effectively. Moreover, for a low frequency oscillation signal with complex modes, the proposed algorithm is able to isolate the corresponding low frequency oscillation mode and has high detection accuracy of oscillation mode information.