This paper proposes a coordinated reactive power control strategy using a synchronous condenser to improve the High-Voltage Ride-Through (HVRT) ability of a Doubly-Fed Induction Generators (DFIG) wind farm and thus avoids tripping off of wind turbines. Because of its dynamic reactive power support and strong short-time overload capacity, the large capacity synchronous condenser has now been widely deployed in HVDC systems. However, the reactive power support of a synchronous condenser lags because of its response time limit when the grid fails. Based on the reactive power characteristics of a DFIG and synchronous condensers, a coordinated reactive power control strategy is proposed to optimize the reactive power flow during grid voltage swell. With the synchronous condenser deployed, the DFIG wind farm is controlled to participate in reactive power compensation during fault transients. The wind farm stops reactive power compensation during the steady-state period after a fault, so that the wind farm can enter normal operation more quickly after fault recovery. The simulation results in the case of DC-link block, small reactive power disturbance and continuous commutation failure show that the proposed strategy can effectively reduce the peak terminal voltage of wind turbines and accelerate system voltage recovery. This work is supported by National Natural Science Foundation of China (No. 51577075) and Science and Technology Project of State Grid Jiangxi Electric Power Company “Research on Configuration Principles and Coordinated Control Technology of Second and Third Defense Lines in Jiangxi Power Grid”.