the external volt-ampere characteristic of the rectifier and inverter station of the VSC-HVDC (Voltage Sourced Converter-High Voltage Direct Current) system is simplified and the dc network equivalent circuit of VSC-HVDC system is built. The small signal model of the VSC-HVDC system is then derived. The transmission capacity is calculated under small-signal stability constraints and three influence factors are also obtained. Simulation is conducted by using PSCAD/EMTDC software. The simulation results demonstrate that the transmission capacity of VSC-HVDC system supply a passive network is be ...