Method and apparatus for feeding electrical current into an electrical power supply system

The invention relates to a method for feeding electrical current into a three-phase electrical grid with a first, second and third phase with a first, second and third voltage at a grid frequency, comprising the steps: measuring the first, second and third voltage, transforming the first, second and third voltage into a voltage positive-sequence system and a voltage negative-sequence system according to the method of Symmetrical Components, calculating a first, second and third setpoint current for feeding into the first, second and third phase of the grid respectively, wherein the calculation of the first, second and third setpoint current is performed as a function of at least one value of the voltage positive-sequence system and/or the voltage negative-sequence system.