In view of the current lack of a generalized control strategy for grid-connected and island operation of voltage source converter based high voltage direct current (VSC-HVDC) transmission system

the AC-side frequency-power droop control and the DC-side power-voltage droop control are introduced

based on which the generalized control strategy for VSC station is proposed. The proposed control strategy can be effectively applied to both grid-connected and island operation of VSC-HVDC transmission system while coordinating with both primary and secondary frequency modulation of the grid

which makes it applicable to weak and isolated grids away from the main grid. The effectiveness of the proposed control strategy is validated by the time domain simulation results. This work is supported by the Key Science and Technology Project of State Grid Zhejiang Electric Power Company (No. 5211011306Z4).