Upwind wind turbine and operation method thereof

An upwind wind turbine including a nacelle horizontally rotatably attached to a tower;

• a rotor rotatably attached to the nacelle;
• a hub which is provided at a center portion of the rotor and forms a part of the rotor;
• a plurality of blades which are attached to the hub, form a part of the rotor and are rotatable within a substantially vertical operation plane;
• and a yawing drive device configured to yaw the nacelle to direct the blades upwind, the upwind wind turbine comprising:
• a tilting coupling mechanism configured to couple base end portions of the blades to the hub such that the blades tilt between a normal position in which the blades are present within the operation plane and a retracted position in which the blades are tilted in a downwind direction relative to the normal position;
• a tilting drive means configured to operate in association with the tilting coupling mechanism to switch positions of the blades;
• a rotation stop means configured to stop rotation of the rotor;
• and
• a control means configured to actuate the rotation stop means to stop the rotor in a predetermined rotational position in which the blades tilt without interference with the tower and to actuate the tilting drive means to tilt the blades to the retraced position after stop of rotation of the rotor, to switch the blades to the retracted position.