For the issues that the fault occurs at the output terminal of ac side , The power output capacity of VSC-HVDC decrease that will lead power surplus of DC side and DC voltage rise . Put forward a method to maintain the balance of power transmission and achieveSlow voltage ride through of fan system is proposed in this paper. The unloading device is installed at the dc side to consume the ‘power gap’ energy caused by the imbalance of both ends of VSC-HVDC the fan will not run off-grid and keep the system stable. The simulation results will verify the effectiveness of the method.
