Method for controlling a wind energy farm taking wake effects into account

Abstract

A method for controlling a wind energy farm is disclosed. A wake state of the wind energy farm is determined, including determining wake chains defining wake relationships among the wind turbines of the wind farm under the current wind conditions. For at least one of the wind turbines of the wind energy farm, a lifetime usage is estimated, based on an accumulated load measure for the wind turbine. In the case that the estimated lifetime usage is below a predefined lifetime usage limit, the wind turbine is operated in an overrated state, while monitoring wake effects at each of the wind turbines. In the case that a downstream wind turbine detects wake effects above a predefined wake threshold level, at least one wind turbine having an upstream wake relationship with the downstream wind turbine is requested to decrease the generated wake, e.g. by decreasing power production.