Enhancement of grid transient stability using MMC-VSCH-VDC control

This paper presents a study on capabilities of High Voltage Direct Current connection (HVDC) based on Voltage Source Converter (VSC) technology in Modular Multilevel Converter (MMC) topology to enhance transient stability of a large power system in fast and large voltage fluctuation events. A fast voltage support (FVS) control is equipped to the standard control of the MMC-VSC station. The use of FVS control together with active/reactive power (P&Q) coordination control to maximize the capability of MMC-VSC-HVDC in supporting system voltage is analyzed. Furthermore, the performance of MMC-VSC station control operated under a special operational mode, STATCOM mode, during short circuit in DC grid is as well discussed and highlighted.