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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。
The Hilbert-Huang transform (HHT) is used in the harmonic detection of electrified railway. By this method, harmonic signals of arbitrary frequency can be extracted. In order to solve the problem of modal aliasing which may be caused by the direct application of empirical mode decomposition (EMD), EMD based on Fourier Transform (FT) is used to extract harmonic signals from electrified railway. First of all, the part of the specified frequency is filtered by Fourier transform, and then the HHT transform is performed separately and recombined to obtain the complete intrinsic mode function (IMF) component of the signal, and then the Hilbert spectrum is calculated. Get the Hilbert spectrum of the harmonic signal. The measured harmonic voltage and current data of the electrified railway traction substation are analyzed. The simulation results show that the accurate time-frequency distribution of each harmonic in the electrified railway can be obtained by using the improved HHT method.