一种暂稳态电力谐波的HVD检测方法

摘要

将希尔伯特振动分解(HVD)方法应用于非平稳电力谐波分析.在剖析非平稳多谐波信号的希尔伯特变换瞬时频率表达式基础上,通过低通滤波器直接佑计出幅值最大谐波分量的瞬时频率,由同步检测获得相应的幅值和初相角,通过迭代运算自适应地检测出各次时变谐波分量参数.根据电网谐波的特点,设计一种满足性能指标的FIR低通滤波器实现HVD算法的关键环节,并采用波形匹配自适应边界延拓法避免截断处理的边界效应和累积误差.仿真表明,该方法能准确检测出频率波动和幅值突变等暂态谐波并适用于德态谐波分析,与小波变换相比,无需选取基函数且精度与运算效率更高.%A novel Hilbert vibration decomposition (HVD) method is introduced to the non-stationary harmonic analysis in electrical power system. Based on the decomposition of non-stationary signal, according to the Hilbert transform, the non-stationary frequency of the largest harmonic component is estimated by the low-pass filter of the instantaneous frequency of analytical signal. The corresponding envelope and the phase are estimated by the synchronous demodulation. Every time-varying harmonic composition can adaptively be extracted at each iteration step. FIR filter is used to remove the rapidly varying asymmetrical oscillating part. A kind of wave characteristic matching extending method is proposed to ensure the high precision of non-stationary harmonic analysis. The new method has the characteristics of wavelet multiresolution and time-frequency localization, but not involves basic functions. Simulation results show that it can detect steady state and frequency fluctuation harmonic. By using the method, the beginning and ending time of amplitude variation harmonics can be accurately located. Numerical results prove the effectiveness of the proposed method for non-stationary harmonic analysis.