Research on Harmonic Resonance Mitigation Based on Improved Modal Sensitivity Analysis

Among the methods used for mitigation of harmonic resonance, modal analysis theory and modal sensitivity can be used to illuminate the nature and properties of this phenomenon, and are thus widely applied. In this paper, an improved modal sensitivity-based method is proposed to reliably suppress the harmonic resonance. First, we show that the current resonance mitigation schemes that are guided by traditional modal sensitivity are not always robust in some cases. Then, through a theoretical analysis, the roots of the shortcomings of the traditional modal sensitivity are determined. The key factor is that the modal sensitivity of a network component is not always constant but tends to vary with adjustment of the component parameters. Finally, to quantify this sensitivity variation and improve the robustness of the analysis results, a second-order modal sensitivity and a critical index are proposed. The results of the test system indicate that the proposed indexes can accurately show the effects of each network component on the resonance, thus are useful in the design of the corresponding mitigation scheme.