For the low-voltage/high-voltage chain off-grid problems of wind power

this paper develops a transient mathematic model with consideration of recovery stage of grid voltage dip

and analyzes its dynamic characteristics. The effect of the recovery stage on the medium and high voltage ride-through processes in the cascading trip-off fault is analyzed. The free component of the stator flux linkage will be generated during the grid voltage dip

and it is a key factor for the recovery stage of grid voltage dip. Therefore

taking the free component of the stator flux linkage as the entry point

this paper deduces the stator and rotor current expressions with consideration of this stage

and analyzes and quantifies the effect of free components of the stator flux linkage generated and different fault parameters on the high voltage ride-through process. Finally

through simulation and verification

the rationality of the derived stator and rotor current expressions and the correctness of the transient model are verified.