一种电力系统谐波与间谐波频谱互扰抑制方法研究

Research on Spectral Interruption Suppression Method for a Kind of Power System Harmonic and Interharmonic

用离散傅里叶变换分析电力系统谐波和间谐波时,各成分间的频谱干扰是引发分析误差的主要原因。提出了一种基于加窗时域平均的谐波间谐波分离分析法。该方法首先对采样信号进行加窗处理,对加窗后的离散信号进行时域平均,滤波得到拟谐波信号,对拟谐波信号做离散傅里叶变换,得到各次谐波参数。用原始采样信号减去拟谐波信号,得到差分信号,对其时域序列末尾补零加密其频域谱线,峰值搜索求得间谐波参数。该方法能够有效实现谐波和间谐波在时域的分离,抑制其在频域相互干扰;间谐波间的干扰及正负频率成分间的干扰同样可以得到有效的抑制。

When the discrete Fourier transform （DFT） is used to analyze the power system harmonics and interharmonics, spectral inter-ruptions between different frequency components are the main factor that causes the analysis errors for harmonics and inter-harmonics. This paper proposed a kind of harmonics and inter-harmonics separation analytical approach based on the windowed time domain averaging （TDA）. First, each sample point was weighted by the weighing window, then harmonics could be extracted by TDA, and the corresponding parameters could be obtained by DFT. The difference signal was got by subtracting harmonics from the original signal, thus interharmonic parameters could be obtained by zero padding of its time domain sequence to encrypt its frequency domain spectral line and peak searching. This method could effectively separate harmonics and inter-harmonics from the initial signal in the time-domain, strongly restrain the inter-ruptions between haromnics and inter-harmonics, positive and negative frequency components.