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With the increasing penetration of distributed generations （DGs） into power grids, the fault ride-through ability of DG is attracting more and more attention. Recent grid codes require a DG to maintain its connection with the grid during grid faults and to play an active role in the recovery of grid voltage. This paper chooses the doubly- fed induction generator （DFIG） as the typical wind turbine for study. Firstly, a dynamic reactive power control strategy is proposed to improve the fault ride-through characteristic of a DFIG. The contributions of a DFIG to the fault current under the dynamic reactive power control and the Crowbar control are analyzed and compared based on the mathematical expressions and control behaviors. The impacts of a DFIG under two control strategies on distribution protections are discussed. Studies show that although a DFIG under the dynamic reactive power control provides more fault current component than one under the Crowbar control, its impacts on distribution protections are acceptable. Finally, a 10 kV distribution network with a DFIG is simulated in PowerFactory DIgSILENT. The simulation results prove the correctness of above theoretical analysis.