A New Method to Calculate the Utility Harmonic Impedance Based on FastICA

Based on fast independent component analysis, a new method is proposed to calculate the utility harmonic impedance. Since the utility harmonic change is negligibly dependent on the customer, four independent components are obtained by demixing X-Y orthogonal components of voltage and current fluctuations at the point of common coupling. Then, mixing coefficients can be figured out by ordinary least square. Finally, the utility harmonic impedance is calculated according to the linearity of mixing coefficients. The disturbance of the utility harmonic is reduced to a certain extent by this method, which is because the joint impact of both sides is taken into account. According to analyses of simulation and field test cases, it is proved that utility harmonic disturbances can be effectively restrained by the proposed method; thus, more accurate utility harmonic impedance can be obtained.