Control strategy of VSC-HVDC inverter supplying power to the isolated grid with induction motor

High voltage direct current transmission system based on voltage source converter (VSC-HVDC) can supply power to the weak AC network or the passive network. When the only generator in an isolated grid is out of operation, the isolated grid supplied by VSC-HVDC will become the passive network and the research about how to control the inverter of VSC to ensure safety and stability of the isolated grid during the fault has great importance. In this paper, the transfer function model of passive network is built with considering the inertia of the induction motor. An additional frequency control strategy for VSC-HVDC inverter is proposed in the paper. The performance of VSC-HVDC system supplying power to the active AC network and the passive network with the additional control strategy is simulated in PSCAD/EMTDC. The simulation results verify the correctness of transfer function model and the effectiveness of the proposed control strategy.