Reactive Power Support Strategy of VSC-MTDC for Low AC Voltage Ride Through

The multi-terminal VSC-HVDC (VSC-MTDC) considered a feasible technology for the interconnection of AC systems with different characteristics, and the integration of renewable energy. For the master-slave control of the VSCMTDC, the active power dispatched by the VSC-MTDC need to be balanced quickly by the master station, or the active power surplus/shortage in DC system will result in DC voltage rise/drop. Considering active power balance ability of the master station is decline during low voltage ride through process of the connected AC system, the reactive power support strategy of VSC-MTDC is proposed in this paper to enhance the active balance ability of the master station during low voltage ride through process, through the way of coordinating reactive power support provided by the master station itself and the nearby reactive power source. The theoretical analysis and the simulations results based on PSCAD/EMTDC have verified the effectiveness of the proposed control strategy.