Hilbert-Huang变换在电气化铁路谐波检测中的应用

将Hilbert-Huang变换(Hilbert-Huang transform，HHT)用于电气化铁路谐波检测中，应用该方法可以提取任意频次的谐波信号。为了解决直接应用经验模式分解(empirical mode decomposition，EMD)方法可能出现的模态混叠问题，文中采用基于傅里叶变换(Fourien tranform，FT)的EMD方法对电气化铁路谐波信号进行提取。首先利用傅里叶变换对指定频率部分进行滤波，然后分别进行HHT变换，再重新组合，即可得到信号全部完整的本征模态函数(intrinsic mode function，IMF)分量，进而计算其Hilbert谱，得到谐波信号的Hilbert谱值。对电气化铁路牵引变电站实测谐波电压、电流数据进行了分析，仿真结果表明利用改进的HHT方法可以得到电气化铁路各次谐波的准确时频分布。

Application of Hilbert-Huang Transform in Harmonic Detection of Electrified Railway

In this paper the Hilbert-Huang transform (HHT is applied to harmonic detection in electrified railway, by use of the proposed method harmonics with any frequency can be extracted. To solve the mode mixing that may be caused by directly utilizing empirical mode decomposition (EMD) method, the extraction of harmonic signals in electrified railway is carried out by adopting Fourier transform (FT) based EMD. Firstly, by use of FT the filtering of specified frequency bands is performed; then the HHT is applied to filtered results respectively, after the recombination of these HHT processed signals all intrinsic mode function (IMF) components of original harmonic signal can be obtained; thirdly, by means of calculating the Hilbert spectrum of IMF components the Hilbert spectral value of harmonic signal is achieved. Comparing with the results of analysis on current and voltage data measured in traction substation of electrified railway, simulation results show that by use of the improved HHT the precise time-frequency distribution of harmonics in electrified railway can be obtained.