operator whereby especially p n is influenced by the grid and the transformer inductance as l as well as by the torque of the turbine therefore a target value for u c that is needed in principle is first predefined k p is a proportional control gain and is likewise predefined in order to additionally dampen the system a corresponding term can be added with a differential control gain k d the value of k d is likewise predefined and the values for k p and k d are selected in such a way that the system responds quickly no strong oscillations occur after transitions and there are as few harmonics as possible the expression for the displacement angle u03b4 u2032 can then be written as for small values of the damping k d the current in the intermediate circuit according to formula 17 can be approximated by means of using these equations the following expression for the behavior according to formula 18 in the intermediate circuit is obtained c k p u2062 u2146 2 u2062 u03b4 u2146 t 2 i k u2062 cos u2062 u2062 u03b4 u2062 k d k p u2062 u2146 u03b4 u2146 t i k u2062 sin u2062 u2062 u03b4 i r 24 which is a result similar to the swing equations of the generator according to formula 14 in order.