Stability analysis of multi-infeed HVDC system applying VSC-HVDC

This paper presents a general model of dual infeed HVDC system applying VSC-HVDC, which can be used as an element in large multi infeed HVDC system. The model may have different structure under different grid faults because of the action of breakers. Hence power flow of the system based on this model is analyzed under steady state and different kinds of grid fault transient situations. Two main control methods applied on VSC-HVDC link in this dual infeed HVDC system are investigated, and comparative analysis of them under transient situation is presented. A simulation model is built in PSCAD/EMTDC to verify the theoretical analysis. Simulation results indicate that this dual infeed HVDC system can realize higher stability than single infeed HVDC system. And different control strategies on a VSC-HVDC link may result in different influence on AC voltage and active power oscillation during transient situation.