Research on startup circuit parameter selection and startup control strategy for multi-terminal VSC HVDC system

The startup of multi-terminal VSC HVDC system is not only one of the key conditions to be considered in the system design, but also the basis for the system to operate normally. In this paper, the detailed theoretical analysis and simulation calculations are carried out for each stage of the charging process of VSC. Furthermore, the parameter selection principle and technical requirements of start-up resistor and netural grounding resistor of each station are proposed. Smooth start-up control strategy is designed to reduce equipment cost and communication dependence between stations. The proposed parameter selection principles and control strategy of start-up circuit have been verified by Nan'ao VSC-MTDC project.