The receiving end hybrid LCC-MMC HVDC transmission system uses line commutated converter（LCC） at the rectifier side

and LCC and modular multilevel converter（MMC） are connected in series at the inverter side. When the AC voltage at sending end falls

the DC voltage of the rectifier side will be reduced which affects the power transmission of the system. In this paper

the influences of different levels of the AC voltage sag at sending ends on the operating characteristics of DC transmission system at receiving ends are analyzed

and a voltage coordination control logic of the hybrid system is optimized based on the cooperation of MMC voltage control and VDCOL. Thereby

MMC switch between the normal operating state and the voltage-reduced operating state can be realized adaptively. The results of modeling and simulation of receiving end hybrid HVDC transmission system on the PSCAD/EMTDC indicate that the proposed adaptive voltage coordinated control method can be adopted to increase the transmission power of the DC system during low voltages.