Patent ID: 8247913

Claim:
A method for operating a wind energy installation, comprising: determining an oblique incident flow value at rated wind speed, the oblique incident flow value representing a difference between a wind direction and a direction of a rotor axis of a wind energy installation; determining a load value representing a load state of the wind energy installation at rated wind speed, wherein the load value is determined based on an increase in the rotor rotation speed or wherein the load value represents an indicator that the wind energy installation is subject to an oblique incident flow; calculating a total load value based on the load value and the oblique incident flow value using a functional relationship in which the total load value varies monotonically as a function of the load value and the oblique incident flow value; reducing a rotor rotation speed of the wind energy installation after the total load value has exceeded a first limit value; and shutting down the wind energy installation when both the total load value has exceeded the first limit value and a second limit value is exceeded which is directly or indirectly dependent on a total load on the wind energy installation.