Decomposition and mitigation of a disturbance being present at an electric connection between an electric power generating system and a power grid

A method for mitigating a disturbance on an electric signal presented at an electric connection between an electric power generating system including a power converter and a power grid, wherein a first disturbance with a first strength is associated with the electric power generating system and a second disturbance with a second strength is associated with the power grid, comprising:

• determining the strength of the first disturbance,
• deriving a control signal based on the determined strength of the first disturbance, and
• controlling the operation of the electric power generating system in response to the control signal in such a manner that the sum of harmonic currents emitted by the power converter and harmonic currents caused by background harmonics of the power grid is minimized,
• wherein determining the strength of the first disturbance comprises:
• determining a voltage value of a voltage of the electric signal;
• determining a current value of a current of the electric signal;
• calculating a value of an open circuit voltage of an equivalent voltage source based on the determined voltage value, the determined current value, and a characteristic equivalent impedance of the electric power generating system so that the electric power generating system is in a harmonic model;
• and
• determining the strength of the first disturbance based on the calculated value of the open circuit voltage of the equivalent voltage source.