基于互信息数据优选的系统侧谐波阻抗估计

谐波阻抗求解是谐波治理和合理谐波责任划分的前提。现有的谐波阻抗估计方法需要满足背景谐波波动小且用户侧谐波阻抗远大于系统侧谐波阻抗的条件。但电力系统中大量电力电子设备的使用导致这些条件可能难以满足。因此，本文提出一种基于互信息数据优选的系统侧谐波阻抗估计方法。首先通过独立分量分析(independent component anal-ysis, ICA)求解系统侧谐波电流，再筛选公共连接点(point of common coupling, PCC)处谐波电流与系统侧谐波电流互信息小的数据段，最后利用所筛数据段所对应的PCC处谐波电流与系统侧谐波电压协方差为零的特性估计谐波阻抗。与现有方法比较，本文所提出的方法在两侧谐波阻抗不满足远大于的情况下系统侧谐波阻抗估计结果更准确，适用范围更广泛。文章通过仿真实验和实测数据分析检验了该方法的有效性。

Utility harmonic impedance estimation based on mutual information and data optimization

Harmonic impedance solution is the premise of harmonic control and reasonable harmonic responsibility division. The existing harmonic impedance estimation methods should meet the conditions that the background harmonic fluctua-tions are small and the customer-side harmonic impedance is much larger than the utility-side harmonic impedance. But the use of a large number of power electronics in power system makes those conditions not satisfied. Therefore, this paper proposes a utility-side harmonic impedance estimation method based on mutual information and data op-timization. First, the utility-side harmonic currents are solved by independent component analysis(ICA), then the data segments with small mutual information between the harmonic currents at the point of common coupling(PCC) and the utility-side harmonic currents are selected. Finally, the harmonic impedance of the screened data segment is esti-mated using the characteristic of zero covariance between the harmonic current at the PCC and the harmonic voltage on the utility-side. Compared with existing methods, the proposed method is more accurate and widely applicable when the customer-side harmonic impedance is not much larger than the utility-side harmonic impedance. The effectiveness of the method is tested by simulation experiments and measured data analysis.