一种基于EEMD的新型谐波误差分析策略

针对电力系统中严重的谐波干扰问题,为提高其运行的安全有效性,去除谐波干扰并提高系统稳定性能成为研究热点。电网中常存在频率强烈波动或者白噪声强烈干扰的现象,虽说三谱线插值的FFT算法(基于Kaiser窗)的抗干扰能力很强,谐波参数估计也可以有较高的精准度,但是远不及使其与平均经验模态的总体水平来分解谐波的检测算法(EEMD)与直线度误差分析相结合。应用直线度误差来分析信号的谐波成分,有机结合了三谱线插值的FFT(基于Kaiser窗的)谐波检测分析法。通过对整体谐波分量的在线监测,不仅能够提高稳态信号的检测精度,还能提高系统的动态性能。本分析策略大限度地提高了计算精度以及系统稳定性。通过仿真分析得知,所述方法可以使系统具有较强的抑制频谱泄露能力,并能够显著降低栅栏效应的发生概率,进而使电力谐波信号的幅值误差、初相位误差和频率误差分别低于0.004 1%、0.002 4%和0.003 9%。

A new harmonic error analysis strategy based on EEMD

There is a serious harmonic interference problem in the power system, and in order to enhance secure and effective operations, removing the harmonic interference and improving system stability becomes a hot research topic. As for the challenges of strong fluctuations in the grid frequency or frequent intense white noise interference, although the FFT algorithm for triple spectrum line interpolation (based on Kaiser window) has strong anti interference ability, and the harmonic parameter estimation may also have a higher accuracy, the combination of the modal harmonic detection algorithm (EEMD) and the straightness error analysis has better effect. On line monitoring of the overall harmonic components can improve not only the detection precision of the steady state signals, but also the dynamic performance of the system. The proposed analysis strategy can improve calculation accuracy and system stability. Simulation analysis proves its strong capability in preventing spectrum leakage and reducing the probability of fence effect significantly. The amplitude error of power harmonic signals, initial phase and frequency are less than 0.004 1%, 0.002 4% and 0.003 9%, respectively.