Research on Voltage Control Strategy of VSC-MTDC Transmission System

A multi-terminal HVDC system (MTDC) based on voltage source converter (VSC) is built in PSCAD/ EMTDC in this paper. Each converter station has three-phase bridge topology with IGBT. Its control system is designed to realize the real power control, reactive power control and DC voltage control. The principles of voltage deviation control and voltage-power drop control in VSC are analyzed. Considering the problems of voltage deviation control, an improved DC voltage control strategy is put forward. Simulation results show that integrated voltage control has quick response, power flow self-regulation, small overshoot and enhanced stability.