A “Critical Impedance”-Based Method for Identifying Harmonic Sources

This paper proposes a new method to determine whether the utility or the customer side has more contribution to the harmonic currents measured at the point of common coupling. The method is inspired by the observation that the direction of harmonic reactive power, instead of active power, is a more reliable indicator on the location of dominant harmonic sources. The method needs approximate impedance information to operate. Mathematical analysis, simulation studies, and field measurements have shown that this is a useful, reliable, and practical solution for the harmonic source detection problem.