A rotational speed controlling device for a wind turbine is provided. The controlling device includes a first input node for receiving a first signal, indicative of an actual rotational speed of the rotor, a second input node for receiving a second signal, indicative of a reference rotational speed for the rotor, a detection unit for detecting a defective operational state in which the wind turbine is impeded to export electrical power to an electricity network, a control unit for providing a reference signal for a characteristic operational parameter of the wind turbine based on the first signal and the second signal, and a pulse generator adapted to send a kick pulse to an integral control element of the control unit in response to the detection of the defective operational state. The characteristic operational parameter is indicative of the rotational speed of the rotor.