Method for reducing extreme load of wind power generation unit under halt conditions

The invention discloses a method for reducing the extreme load of a wind power generation unit under halt conditions. According to the method, the windward area of the wind power generation unit in the 90-degree direction and the 270-degree direction is reduced during a halt through the local variable pitch of blade tip parts; meanwhile, through combination with optimal yaw control, the load of the wind power generation unit during the halt under the extreme wind conditions; when the wind power generation unit is shut down and feathered under the extreme wind conditions, the wind direction andthe wind speed are monitored in real time through a wind indicator and an anemograph on the wind power generation unit; when limit-speed wind is blown from the side face of the unit. the blade tip parts locally change the pitch by 90 degrees; the area of blades in the 90-degree direction and the 270-degree direction is effectively reduced through the local variable pitch method. Aerodynamic loadof wind power on the unit