基于数学形态学和HHT的谐波和间谐波检测方法

A New Method to Detect Harmonics and Inter-Harmonics Based on Mathematical Morphology and Hilbert-Huang Transform

非线性电力元件的应用使电力系统的谐波污染问题日益突出。为准确检测谐波和间谐波参数,提出了基于数学形态学和希尔伯特-黄变换(Hilbert-Huang transform,HHT)的谐波和间谐波检测方法。为有效抑制多种噪声,对现有数学形态滤波器进行了改进,使之保留了原信号的主要特征,并运用经验模态分解处理消噪后的信号,得到了一组经验模态函数分量。对每个经验模态函数分量进行希尔伯特-黄变换,可准确得到其瞬时频率和瞬时幅值,实现了在噪声背景下对谐波和间谐波的检测。仿真结果验证了该方法的可行性与有效性,表明其可提高谐波和间谐波的检测精度。

The extensive application of non-linear power components makes the harmonic pollution situation of power system increasingly severe. To detect the parameters of harmonics and inter-harmonics, a mathematical morphology and Hilbert-Huang transform （HHT） based method to detect inter-harmonics and harmonics is proposed. To effectively suppress noises, existing mathematical morphology filter is improved in which the main characteristics of original signal are reserved and the de-noised signal is processed by empirical mode decomposition （EMD） to obtain a set of intrinsic mode function （IMF） components. Applied Hilbert transform to each IMF component, the instantaneous frequency and instantaneous amplitude of the component can be accurately determined, and thus the detection of harmonics and inter-harmonics under noisy background is implemented. Simulation results validate the feasibility and effectiveness of the proposed method and it is shown that the detecting accuracy of harmonics and inter-harmonics can be improved by use of this method.