基于全相位FFT时移相位差的电网间谐波检测

Measurement of interharmonics in power network based on all phase FFT time shifting and phase difference

电网间谐波所造成的危害越来越引起人们的重视,电网间谐波的实际测量结果是间谐波问题研究的主要依据。为克服传统FFT检测间谐波误差大的缺陷,提出一种全相位FFT(apFFT)时移相位差的间谐波检测方法。用apFFT算法,同时调整采样率能抑制包括基波的所有0.1次整数倍谐波的频谱泄漏,用主谱线的相位差来校正频率值和幅值,相位值无需校正,直接取apFFT主谱线上的相位值。此算法概念清晰,结果直接,具有抗谐波间干扰强的优点。仿真结果表明,该方法能高精度地检测间谐波的大小、相位和频率,为电网间谐波检测和分析提供了一种新的有效途径。

The harms brought by interharmonics have attracted people＇s attention more and more.The research of interharmonics is based on the actual measurement of the interharmonics in power network.An interharmonics detection method of all phase fast Fourier transform（apFFT） time shifting and phase difference is proposed in order to overcome the defects of the bigger measurement error brought by traditional FFT algorithm.By adopting apFFT algorithm and adjusting sample rate,we suppress spectrum leakage of all 0.1 times integer time harmonics including fundamental.Frequency and amplitude corrections are obtained through main spectrum line phase difference.The apFFT main spectrum lines phase values without correction are directly taken as phase values.The concept is clear and the results are direct.The algorithm has the advantage of strong anti-interference between harmonics.The simulation results show that the proposed method can detect amplitude,phase and frequency of interharmonics with high precision.The algorithm provides a new effective way for power network interharmonic detection and analysis.