Patent ID: 7982325

Claim:
A method of operating a wind power installation connected to a network for distribution of electrical power, said wind power installation comprising at least one wind power generator, said wind power installation being related to said network for injection of power into said network, said network having a nominal network frequency (f n ) and said network being arranged for operating at the nominal network frequency, wherein said method comprises controlling the active power that is injected into said network from said wind power installation in view of a measured actual network frequency (f a ) at which said network is operating, said method comprising the steps of: measuring the actual network frequency (f a ); and determining a difference (E) between the actual network frequency (f a ) and the nominal network frequency(f n ); said method further comprising the step of, if said difference (E) is larger than a predefined threshold, adapting by means of a controller the amount of active power that is injected into said network from said wind power installation, in a manner that depends on a magnitude of the difference (E), a duration of the difference (E), and a rate of change of the controller output so as to bring the actual network frequency (f a ) back towards the nominal network frequency (f n ).