A method for controlling a power generation plant

The invention refers to a method for controlling a power generation plant comprising a number of generators (WT) connected to an electric power grid (G), wherein for each generator (WT) a voltage set point (|V ter | ref ) for a terminal voltage magnitude (|V ter |) at a terminal of the generator (WT) and a power set point (P ref ) for the active power (P) generated by the generator (WT) are fed to a control means of the generator (WT), where the control means adjusts in subsequent control steps a reactive current (I d ) and an active current (Iq) provided by the generator (WT) so that the terminal voltage magnitude (|V ter |) and the active power (P) reach the voltage and power set points (|V ter | ref , P ref ). The method of the invention estimates the reactive current based on an appropriate electric circuit model and uses this estimated current in order to check whether dynamic constraints of the power generation plant are met. If not, the voltage and/or power set points are adjusted. Due to the continuous variation of those set points, corresponding control saturation limits are met enabling a stable operation of the power generation plant even for weak power grids. In a preferred embodiment, the invention is used for controlling a power generation plant in the form of a wind farm comprising one or more wind turbines as generators.