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针对现有电力系统非整数次谐波分析法的不足,提出了一种改进的希尔伯特振动分解(HVD)方法。该方法根据对解析信号瞬时频率的分析,巧妙地通过平滑滤波获得非整数谐波成分中幅值最大分量的频率,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非整数次谐波的各次频率、幅值和相角。虽然HVD方法和希尔伯特黄变换(HHT)方法这两者均以希尔伯特变换为基础,但HVD方法避免了复杂的经验模式分解(EMD)过程。采用Savitzky-Golay滤波替代平滑滤波,在保留有效频率成分情况下可极大地消除快速变化不对称振荡高频值;提出的新波形特征匹配边界延拓可消除边界效应的影响,使得非整数次谐波分析更准确。仿真实验证明了改进的HVD方法对非整数次谐波检测的有效性。
Aiming at the deficiency of non-integral harmonic analysis in power system, an improved Hilbert-Vibration Decomposition (HVD) method is proposed. Based on the analysis of the instantaneous frequency of the analytic signal, the method cleverly obtains the frequency of the largest component of the non-integer harmonic components by smoothing filtering, obtaining the corresponding amplitude and initial phase angle from the synchronous detection and adaptively detecting by iterative operation The non-integer harmonics of the frequency, amplitude and phase angle. Although both the HVD method and the Hilbert transform (HHT) method are based on the Hilbert transform, the HVD method avoids the complicated empirical mode decomposition (EMD) process. By using Savitzky-Golay filter instead of smoothing filter, the fast changing high frequency of asymmetric oscillation can be eliminated greatly while preserving the effective frequency components. The proposed new waveform feature matching boundary extension can eliminate the influence of boundary effect, Wave analysis more accurate. Simulation results show the effectiveness of the improved HVD method for non-integer harmonic detection.