With the increasing size of wind farm, cascading fault often occurs. Automatic reclosing will make the voltage drops twice when permanent faults occur in the power system, causing a chain of adjacent wind farm off the grid, which poses a great threat on the safety and stability of the wind farm. This paper analyzes the mechanism of the chains of the wind farms off-grids caused by twice voltage drops from the aspect that the initial stator flux of DFIG differs between the twice moment when the voltage drop when the short-circuit fault occurs on the 110 kV wind farm connection line. On this basis, this paper proposes two methods, namely changing the functional configuration of reclosing and extending the time of reclosing, to solve this problem. And the simulations verify the effectiveness of the two methods.