Impedance Sensitivity Analysis Based Broadband Resonance Suppression Strategies for MMC-HVDC System

Broadband resonance between AC and DC power grids has become an increasingly prominent problem. The influencing factors of resonance among AC/DC hybrid grids are complex and intertwined, while the applicable scenarios of existing suppression measures are limited. To solve this problem, a calculation method of MMC impedance sensitivity is proposed in this paper, and the relative impedance sensitivity evaluation index is established, which can quantitatively determine the dominant influencing factors. Based on impedance sensitivity, the impedance optimization intervals of MMC main circuit and control parameters are constructed, and a targeted broadband resonance suppression strategy is proposed. Finally, based on actual engineering RTDS frequency sweep and time-domain simulation, the correctness of sensitivity calculation method and the effectiveness of resonance suppression strategy has been verified.