For the VSC-HVDC system transmitting new energy,poor parameter matching between the new energy controller and the VSC-HVDC controller can lead to sub-synchronous and super-synchronous oscillation.To address this,an open-loop strategy based on virtual synchronous generator(VSG)control has been adopted.This strategy eliminates the inner and outer loops and the phase lock of traditional closed-loop control methods,optimizing the im-pedance characteristics of the VSC-HVDC system and reducing the risk of sub-synchronous and super-synchronous oscillations of new energy.It is also compatible with both islanded and grid-connected operating modes.To address bi-polar power imbalance and excessive short-circuit current after faults in open-loop control,bipolar power balancing and fault ride-through(FRT)strategies have been proposed.The effectiveness of the proposed VSG control and FRT strategies has been validated through RTDS simulations.
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