A wind power generation system temporarily stops a power converter when a system disturbance occurs, and reactivates the power converter after detecting a solution of the problem of an influence (overcurrent of a stator, direct current component of a stator, overcurrent of a rotor, etc.) of a fault occurring in a doubly-fed generator during a system fault. During a system fault, a reactive current can be safely output from a doubly-fed generator to an electric power system without destroying equipment of the wind power generation system.