High-Frequency Small-Signal Stability of MMC-HVDC Transmission Systems with Grid Resonance

Modern Modular Multilevel Converter - High-Voltage Direct Current (MMC-HVDC) systems built by different vendors will be installed and be operated in the high-voltage transmission grid. The modular structure of MMC facilitates the hardware realization of HVDC systems, yet the interactions between the internal power modules and external dc and ac systems pose new challenges on the small-signal stability of HVDC systems. In order to ensure a certain level of power system security of supply, the identification and quantification of interaction modes between the MMC-HVDC stations and the grid resonance at the connection point become essential.