Harmonic mitigation potential of shunt harmonic impedances and the influence of background distortion

Although complete compensation is only possible using true active filters, shunt harmonic impedances (SHI) have been shown to provide a considerable reduction of the harmonic propagation. In this paper, the mitigation potential of different shunt harmonic impedances is investigated, together with their VA-rating. It is shown that a resistive impedance of 1 pu for all harmonics is very effective, especially in the case of power system resonances. The analysis presented considers also the influence of the PHI on the line current injected into the power system when background distortion is present. To take into account the interaction between harmonics, simulations are performed in the presence of a realistic nonlinear load, instead of the common harmonic current source modelling approach.