改进的HHT算法在电力系统谐波检测中的应用

The Application of Improved HHT Algorithm in Power System Harmonic Detection

使用改进的HHT方法检测电力系统谐波。由于HHT方法存在模态混叠现象,不能有效的得到各次谐波分量。采用预处理的方法,首先将一个信号通过一级低通滤波器得到一级高频成份和一级低频成份,一级高频成份进一步分解为二级高频成份和二级低频成份,如此类推直到满足分解完成条件。对各个频带进行EMD分解得到IMF分量,最后将所有的IMF分量进行Hilbert变换得到各次谐波分量的瞬时频率。此方法能够有效的解决模态混叠问题。利用Matlab的Simulink平台建立电力系统谐波源模型以仿真电力系统谐波电流信号,并利用此方法进行分析。仿真研究表明,该方法能够比较精确的分析电力系统中的谐波信号。

Using improved HHT method for power system harmonic detection.As HHT method has modal aliasing phenomenon,each harmonic component cannot be effectively draw.In this paper, the pretreatment signal method was used in the decomposition process.First a signal through a low pass filter get a high frequency component and a low-frequency component,the high frequency component was further broken down into two highfrequency components and two low-frequency components,and so on until meet decomposition complete conditions.Then,using the EMD decomposition respectively to each frequency band to get IMF,and finally using the hilbert transform to get the instantaneous frequency of each harmonic component.This method is an effective solution to the modal aliasing of the HHT method.Using simulink platform of Matlab to establish the power system harmonic source model and simulat the harmonic current signal,and using the improved HHT method to analyze.This study show that the method can be more precise analysis of the power system harmonic signal.