Grid impedance identification considering the influence of coupling impedances

In this paper the identification of grid connection points is analyzed. These points, also referred to as PCCs (Points of Common Coupling), are used to connect electrical equipment to the grid. The method described in this paper allows to set up a mathematical model for any PCC that reflects its behavior. The grid and input coupling impedances of an equivalent circuit can be determined. The obtained grid impedance can be used to assess the grid feedback, for example of wind-energy converters that feed harmonic currents into the grid.