Patent ID: 8167555

Claim:
A horizontal axis wind turbine comprising: a rotor including a hub and at least two blades; a nacelle to support the rotor with a main shaft connected to the hub; a tower to support the nacelle in a manner capable of performing a yaw rotation; an independent pitch control device to independently control a pitch angle of each of the blades; and a yaw control device to control the yaw rotation of the nacelle, wherein the horizontal axis wind turbine is an up-wind type one including: an operation mode to put the rotor to a windward side of the tower by the control of the yaw control device when a wind speed is a predetermined value or less, and to utilize wind force through a rotation of the rotor; and a waiting mode to wait in preparation for the operation mode when a wind speed exceeds the predetermined value, wherein (1) the independent pitch control device includes a control operation composed of a first step of changing all the blades to be in feathering states when the wind speed exceeds the predetermined value, a second step of changing the blades to be in reverse feathering states one by one sequentially after the first step, and a third step of holding all the blades in the reverse feathering states until a return to the operation mode after the second step, and (2) the yaw control device includes a control operation to control a yaw brake to take a braking value allowing the yaw rotation by torque around a yaw axis, the torque loaded on the nacelle by the wind force, when the wind speed exceeds the predetermined value, wherein the rotor is allowed to swing a leeward of the tower by executing the control operations (1) and (2) as the waiting mode.