基于同步挤压小波变换的电力系统时变谐波检测

针对噪声影响下时变谐波检测问题,提出基于同步挤压小波变换(SWT)的检测方法。首先利用SWT算法将混有噪声的时变谐波信号分解为不同的内蕴模态函数分量(IMTs),进而提取出所含谐波分量,然后对每个谐波分量进行Hilbert变换,得到每个本征函数的瞬时频率和幅值及谐波扰动的起止时刻。基于SWT准确的模态分离能力,实现了各谐波的瞬时频率、瞬时幅值和谐波扰动的起止时刻等参数较高精度的获取。与传统的希尔伯特-黄(HHT)方法相比,该方法对于谐波的分离能力更强,对噪声有更强的鲁棒性。仿真及实际数据表明,所提方法在噪声环境下依然能精确提取各个模态,验证了该方法在时变谐波检测分析中的有效性。

Power System Time-Varying Transient Harmonics Detection Based on SWT

In this paper, a new method for time-varying harmonic detection in the noisy interference background is put forward using synchrosqueezed wavelet transform (SWT). Firstly, the SWT algorithm is applied to decompose the time-varying harmonic signal mixed with noise into a series of intrinsic mode type functions (IMTs), then extracts the harmonic, the instantaneous amplitue, instantaneous frenquency and the starting and ending time of harmonic disturbance are obtained applying Hilbert transform to IMTs. The harmonic parameters are gained precisely by Hilbert transform based on the accurate mode seperation ability of SWT. The proposed SWT method has higher harmonic extration precision for multiple harmonic signals and better robustness against noise compared to traditional HHT. The simulation and real data tests show that the proposed method can extract each mode accurately in the noisy environment, and the validity of the proposed method is verified by time-varying harmonic dection.