Abstract: Controlling a current injected to a power grid from a renewable power plant, in response to a voltage event in the power grid. At least a current at a point of common coupling between the renewable power plant and the power grid is determined and provided to a power plant controller (PPC). The PPC derives individual current setpoint corrections for at least some wind turbines, based on the determined current, and dispatches each derived current setpoint correction to wind turbine controllers of the corresponding wind turbines. The wind turbine controllers control a current output of the respective wind turbines, based on measurements of current and/or voltage at a point of connection between the wind turbine and an internal grid of the renewable power plant, and by taking into account the dispatched current setpoint correction.

Abstract: Controlling a current injected to a power grid from a renewable power plant, in response to a voltage event in the power grid At least a current at a point of common coupling between the renewable power plant and the power grid is determined and provided to a power plant controller (PPC). The power PPC derives individual current setpoint corrections for at least some wind turbines, based on the determined current, and dispatches each derived current setpoint correction to wind turbine controllers of the corresponding wind turbines. The wind turbine controllers control a current output of the respective wind turbines, based on measurements of current and/or voltage at a point of connection between the wind turbine and an internal grid of the renewable power plant, and by taking into account the dispatched current setpoint correction .

Abstract: Aspects of the present invention relate to a method for controlling an amount of reactive current provided from a wind turbine generator to a power grid during an abnormal power grid event, said wind turbine generator comprising a doubly-fed induction generator having a rotor and a stator, and a power converter coupling the rotor to the power grid, the power converter comprising a grid-side inverter, wherein the method comprises the step of balancing the reactive current provided to the power grid between a reactive stator current and a reactive grid-side inverter current, wherein the reactive grid-side inverter current is controlled in accordance with a reactive current capacity of a grid breaker receiving the reactive current provided by the grid-side inverter. Aspects of the present invention also relate to a wind turbine generator being capable of performing the method.

Abstract: Aspects of the present invention relate to a method for controlling an amount of power to be delivered from a wind turbine generator to a power grid during an abnormal power grid event, the method comprising the steps of detecting an abnormal power grid event; controlling an active current delivered to the power grid in response to a measured or determined total active current; and controlling a reactive current delivered to the power grid in response to a measured or determined total reactive current. Aspects of the present invention further relate to a computer program product for carrying out the method as well as a wind turbine generator being capable of carrying out embodiments of the invention.

Abstract: Aspects of the present invention relate to a method for controlling an amount of reactive current provided from a wind turbine generator to a power grid during an abnormal power grid event, said wind turbine generator comprising a doubly-fed induction generator having a rotor and a stator, and a power converter coupling the rotor to the power grid, the power converter comprising a grid-side inverter, wherein the method comprises the step of balancing the reactive current provided to the power grid between a reactive stator current and a reactive grid-side inverter current, wherein the reactive grid-side inverter current is controlled in accordance with a reactive current capacity of a grid breaker receiving the reactive current provided by the grid-side inverter. Aspects of the present invention also relate to a wind turbine generator being capable of performing the method.

Abstract: Controlling a wind turbine during a grid fault where the grid voltage drops below a nominal grid voltage. After detection of a grid fault, the total current limit for the power converter output is increased to a total maximum overload current limit. Depending on whether active or reactive current generation is prioritized, an active or reactive current reference is determined. The active current reference is determined in a way so that a reduction in active power production due to the grid voltage drop is minimized and based on the condition that the vector-sum of the active output current and the reactive output current is limited according to the total maximum overload current limit, and a maximum period of time is determined in which the power converter can be controlled based on the active/reactive current references. Afterwards the power converter is controlled based on the active and reactive current references.

Abstract: A method is provided of controlling a doubly fed induction generator—(DFIG) wind turbine converter system if a sub-synchronous resonance event acts on the wind turbine. According to the method a sub-synchronous resonance event is detected. Thereupon, a switch from a non-SSR-control mode to a SSR-control mode is performed. At least one of the following activities is performed in the SSR-control mode, namely: (i) freezing rotor AC voltages in magnitude and phase, (ii) altering at least one rotor-current-controller gain (iii) altering at least one rotor-current-controller time constant, to dampen the effect of the SSR-event on the wind turbine.

Abstract: Controlling a wind turbine during a grid fault where the grid voltage drops below a nominal grid voltage. After detection of a grid fault, the total current limit for the power converter output is increased to a total maximum overload current limit. Depending on whether active or reactive current generation is prioritized, an active or reactive current reference is determined. The active current reference is determined in a way so that a reduction in active power production due to the grid voltage drop is minimized and based on the condition that the vector-sum of the active output current and the reactive output current is limited according to the total maximum overload current limit, and a maximum period of time is determined in which the power converter can be controlled based on the active/reactive current references. Afterwards the power converter is controlled based on the active and reactive current references.

Abstract: Aspects of the present invention relate to a method for controlling an amount of power to be delivered from a wind turbine generator to a power grid during an abnormal power grid event, the method comprising the steps of detecting an abnormal power grid event; controlling an active current delivered to the power grid in response to a measured or determined total active current; and controlling a reactive current delivered to the power grid in response to a measured or determined total reactive current. Aspects of the present invention further relate to a computer program product for carrying out the method as well as a wind turbine generator being capable of carrying out embodiments of the invention.

Abstract: Controlling a wind turbine during a grid fault where the grid voltage drops below a nominal grid voltage. After detection of a grid fault, the total current limit for the power converter output is increased to a total maximum overload current limit. Depending on whether active or reactive current generation is prioritized, an active or reactive current reference is determined. The active current reference is determined in a way so that a reduction in active power production due to the grid voltage drop is minimized and based on the condition that the vector-sum of the active output current and the reactive output current is limited according to the total maximum overload current limit, and a maximum period of time is determined in which the power converter can be controlled based on the active/reactive current references. Afterwards the power converter is controlled based on the active and reactive current references.

Abstract: The present invention relates to a method for operating a doubly fed induction generator wind power facility during an OVRT event, said the wind turbine facility being adapted to inject active and/or reactive current into an associated grid, the method comprising the steps of determining the occurrence of an over voltage grid event, and maintaining a grid-side inverter of the doubly fed induction generator wind power facility fully operable during the over voltage ride though event so as to maintain a controllable active and/or reactive current capability during the over voltage grid event.

Abstract: A method is provided of controlling a doubly fed induction generator—(DFIG) wind turbine converter system if a sub-synchronous resonance event acts on the wind turbine. According to the method a sub-synchronous resonance event is detected. Thereupon, a switch from a non-SSR-current/voltage control mode to a SSR-control mode is performed. At least one of the following activities is performed in the SSR-control mode, namely: (i) freezing rotor AC voltages in magnitude and phase, (ii) altering at least one rotor-current-controller gain (iii) altering at least one rotor-current-controller time constant, to dampen the effect of the SSR-event on the wind turbine.

Abstract: The present invention relates to a method for operating a doubly fed induction generator wind power facility during an OVRT event, said the wind turbine facility being adapted to inject active and/or reactive current into an associated grid, the method comprising the steps of determining the occurrence of an over voltage grid event, and maintaining a grid-side inverter of the doubly fed induction generator wind power facility fully operable during the over voltage ride though event so as to maintain a controllable active and/or reactive current capability during the over voltage grid event,?