A method for feeding electrical power into an electrical supply grid having a grid voltage having a grid frequency (f N ) at a grid connection point by means of at least one wind power installation or a power plant consisting of at least one wind power installation, comprising the following steps: - specifying a reference system having a reference frequency (fref), a reference phasor (Z ref ) having a reference angle, and a reference amplitude of an output voltage (U ref ) to be generated, wherein the reference angle revolves at the reference frequency and the reference frequency (f ref ) substantially corresponds to the grid frequency (f N ), - specifying a phase angle (φ) as the phase angle between the output voltage (U ref ) and the grid voltage (U N ), - calculating an infeed angle, which revolves with the reference angle, from the specified phase angle, such that the specified phase angle (φ) results as a phase angle between an output voltage generated at the infeed angle and the grid voltage when the reference frequency (f ref ) corresponds to the grid frequency (f N ), - generating the output voltage (U ref ) having a voltage amplitude depending on the reference amplitude, a frequency depending on the reference frequency and the infeed angle and - delayed tracking of the behavior of the grid voltage by the reference system, characterized in that for the delayed tracking: - an actual phase angle between the generated output voltage (U ref ) and the grid voltage (U N ) is detected, - a difference angle between the specified phase angle and the detected phase angle is formed, - the reference angle is changed in such a way that the difference angle is reduced according to the magnitude using a predetermined delay function and - the reference frequency is adjusted to the reference angle changed in this way. - specifying a reference system having a reference frequency (fref), a reference phasor (Z ref ) having a reference angle, and a reference amplitude of an output voltage (U ref ) to be generated, wherein the reference angle revolves at the reference frequency and the reference frequency (f ref ) substantially corresponds to the grid frequency (f N ), - specifying a phase angle (φ) as the phase angle between the output voltage (U ref ) and the grid voltage (U N ), - calculating an infeed angle, which revolves with the reference angle, from the specified phase angle, such that the specified phase angle (φ) results as a phase angle between an output voltage generated at the infeed angle and the grid voltage when the reference frequency (f ref ) corresponds to the grid frequency (f N ), - generating the output voltage (U ref ) having a voltage amplitude depending on the reference amplitude, a frequency depending on the reference frequency and the infeed angle and - delayed tracking of the behavior of the grid voltage by the reference system, characterized in that for the delayed tracking: - an actual phase angle between the generated output voltage (U ref ) and the grid voltage (U N ) is detected, - a difference angle between the specified phase angle and the detected phase angle is formed, - the reference angle is changed in such a way that the difference angle is reduced according to the magnitude using a predetermined delay function and - the reference frequency is adjusted to the reference angle changed in this way. <EOS>