Abstract: Embodiments are generally directed to techniques for operating a wind turbine of a wind power plant. An associated method comprises determining, using one or more sensors of the wind turbine, a first power production level of the wind turbine; determining, during an unconstrained operation of the wind turbine, one or more available power correction factors using the first power production level; determining, using one or more wind power parameters applied to a predefined model for estimating an available power of the wind turbine, an estimated available power value; adjusting the estimated available power value using the one or more available power correction factors to produce the available power value; and controlling, using the available power value, the wind turbine to produce a second power production level.

Abstract: A method for controlling a wind power plant comprising a plurality of wind turbine generators, wherein the method comprises: deriving an estimated value for electrical losses in the wind power plant, deriving a measured value for electrical losses in the wind power plant, based on a difference between an aggregated power production from the plurality of wind turbine generators and a power measurement at a point of common coupling; applying the estimated value for electrical losses and the measured value for electrical losses in an active power control loop, comprising a regulator; and controlling by means of the active power control loop an active power production of the wind power plant at the point of common coupling.

Abstract: A wind turbine system comprising a nacelle mounted on a tower, a rotor having a plurality of blades and a boundary layer control system configured to control airflow through blade surface openings in each of the blades. The wind turbine system includes a control system configured to: monitor an operational speed parameter of the wind turbine, and activate the boundary layer control system if it is determined that the operational speed parameter exceeds a predetermined speed parameter threshold; monitor tower motion and to activate the boundary layer control system based on a determination of excessive tower motion; monitor for a wind turbine shutdown condition, activate the boundary layer control system if it is determined that the shutdown condition has been identified; monitor the aerodynamic loads on the blades, and activate the boundary layer control system based on a determination of excessive blade loads.

Abstract: A method for controlling a wind power plant comprising a plurality of wind turbine generators, wherein the method comprises: deriving an estimated value for electrical losses in the wind power plant, deriving a measured value for electrical losses in the wind power plant, based on a difference between an aggregated power production from the plurality of wind turbine generators and a power measurement at a point of common coupling; applying the estimated value for electrical losses and the measured value for electrical losses in an active power control loop, comprising a regulator; and controlling by means of the active power control loop an active power production of the wind power plant at the point of common coupling.

Abstract: A method and associated control arrangement are disclosed for controlling a power output of a wind power plant (WPP) according to a predetermined power ramp rate limit, the WPP comprising a plurality of wind turbine generators (WTGs). The method comprises receiving a first signal indicating that a first WTG is in a ready state to begin producing power. The method further comprises, upon determining that, responsive to the received first signal, beginning power production of the first WTG at a predetermined default power ramp rate would cause the power output of the WPP to exceed the power ramp rate limit, controlling power production of the first WTG using at least one of: a first delay, a power ramp rate reference less than the default power ramp rate, and a power reference less than a nominal power output of the first WTG.

Abstract: A method for operating a renewable energy power plant comprising a plurality of renewable energy generators. The method comprises: identifying a predetermined condition of the renewable energy power plant, of the grid, or of the connection between the renewable energy power plant and the grid, the predetermined condition indicating a weak grid interconnection between the renewable energy power plant and the grid; and controlling each renewable energy generator in an adaptive active power mode in response to recovery of the grid from a voltage deviation. The adaptive active power mode comprises: determining a thermal capacity of a chopper resistor of the renewable energy generator; calculating, based upon the determined thermal capacity, a limit level of rate of change of active power output that may be implemented by the renewable energy generator; and operating the renewable energy generator to output active power at the calculated rate of change limit level.

Abstract: A method, control arrangement, and wind power plant (WPP) comprising a plurality of wind turbine generators (WTGs) are disclosed. The method includes operating, responsive to a received power demand corresponding to the WPP, a boost group of one or more WTGs of the plurality of WTGs to begin producing a boosted power output, wherein the boosted power output of each of the one or more WTGs of the boost group is regulated independent of the power demand. The method further includes determining, based on a measured amount of boosted power production, power production set points for a regulation group of one or more different WTGs of the plurality of WTGs to thereby meet the power demand.

Abstract: There is provided a method for controlling a hydraulic pitch force system (220) so as to reduce or eliminate a decrease in hydraulic oil pressure (241) if a hydraulic system parameter value is outside a hydraulic system parameter range, the method comprising: Obtaining (690) the hydraulic system parameter value, and operating the hydraulic pitch force system (220) according to a reduced mode (692) if the hydraulic system parameter value is outside the hydraulic system parameter range, wherein in the reduced mode one or more pitch based activities are reduced (694) or suspended. An advantage thereof may be that it enables keeping the wind turbine in production in certain instances rather than shutting down the wind turbine. In aspects, there is furthermore presented a computer program product, a pitch control system (250) and a wind turbine (100).

Abstract: A diagnostic system for use in a wind turbine yaw system, comprising: a tower motion sensor configured to output a signal indicative of tower oscillation, in particular though not exclusively side to side tower oscillation, and a diagnostic module configured to: analyse the tower motion sensor signal to identify frequency content of the signal that is not associated with the tower oscillation; and correlate the identified frequency content with the operation of the yaw system thereby to determine that the yaw system requires maintenance. Beneficially the invention provides that the health of the yaw system can be determined by analysing the oscillatory movement of the tower as measured by a tower motion sensor installed at a suitable location for example at the top of the tower or in the nacelle for example.

Abstract: A method for operating a renewable energy power plant comprising a plurality of renewable energy generators. The method comprises: identifying a predetermined condition of the renewable energy power plant, of the grid, or of the connection between the renewable energy power plant and the grid, the predetermined condition indicating a weak grid interconnection between the renewable energy power plant and the grid; and controlling each renewable energy generator in an adaptive active power mode in response to recovery of the grid from a voltage deviation. The adaptive active power mode comprises: determining a thermal capacity of a chopper resistor of the renewable energy generator; calculating, based upon the determined thermal capacity, a limit level of rate of change of active power output that may be implemented by the renewable energy generator; and operating the renewable energy generator to output active power at the calculated rate of change limit level.

Abstract: A wind turbine system comprising a nacelle mounted on a tower, a rotor having a plurality of blades and a boundary layer control system configured to control airflow through blade surface openings in each of the blades. The wind turbine system includes a control system configured to: monitor an operational speed parameter of the wind turbine, and activate the boundary layer control system if it is determined that the operational speed parameter exceeds a predetermined speed parameter threshold; monitor tower motion and to activate the boundary layer control system based on a determination of excessive tower motion; monitor for a wind turbine shutdown condition, activate the boundary layer control system if it is determined that the shutdown condition has been identified; monitor the aerodynamic loads on the blades, and activate the boundary layer control system based on a determination of excessive blade loads.

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: Embodiments are generally directed to techniques for operating a wind turbine of a wind power plant. An associated method comprises determining, using one or more sensors of the wind turbine, a first power production level of the wind turbine; determining, during an unconstrained operation of the wind turbine, one or more available power correction factors using the first power production level; determining, using one or more wind power parameters applied to a predefined model for estimating an available power of the wind turbine, an estimated available power value; adjusting the estimated available power value using the one or more available power correction factors to produce the available power value; and controlling, using the available power value, the wind turbine to produce a second power production level.

Abstract: Embodiments of the present invention relate to control of a wind turbine during a recovery period after a grid fault. It is disclosed to operate a wind turbine during the recovery period to determine the actual pitch angle of the rotor blades and the actual wind speed, and based on that determining a desired pitch angle of the rotor blades, as well as a pitch ramp rate so that the actual pitch angle can be brought to match the desired pitch angle before the end of the recovery period. In embodiments, the steps performed in the recovery mode are repeated at intervals during the recovery period.

Abstract: The invention relates to a control system for a wind turbine. The wind turbine comprises a power generator configured to generate power dependent on a power reference and a pitch system configured to adjust the pitch of a blade of the wind turbine dependent on a pitch request. The control system comprises a controller configured to determine the pitch request dependent on an adjustable gain. A gain scheduler comprised by the control system is configured to set the adjustable gain to an increased gain value if a rate of change of the power reference, e.g. an external power reference, exceeds a threshold.

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: Embodiments of the present disclosure generally relate to apparatus and methods for preventing power dips associated with power ramping in wind turbines. One embodiment of the present disclosure provides a method for stabilizing power output in a wind turbine, which includes tracking a rate of change in an external reference, such as an external power reference or external torque reference, computing a feed-forward pitch angle adjustment according to the rate of change in the external power reference, and sending the feed-forward pitch angle adjustment to the wind turbine to adjust a pitch angle of rotor blades simultaneously with adjusting power output according to the external reference.

Abstract: The invention relates to techniques for verifying a nacelle yaw position sensor installed on a wind turbine and for taking restorative action to control the nacelle yaw position. The invention relates to a method performing the comprising determining a first absolute wind direction signal associated with the first wind turbine; determining a second absolute wind signal direction signal associated with the plurality of other wind turbines; comparing the two wind direction signals; and issuing a nacelle yaw position sensor fault signal if the first signal is beyond a predetermined error range of the second signal. A benefit of the invention is that it enables the detection of an inaccurate nacelle yaw sensor without direct measurement or inspection.

Abstract: The control of the power output of wind turbine generator that operates in a derated mode to generate a produced power output level lower than an available power level. A pitch system sets the blade pitch of a rotor to a pitch value based on the received power reference signal. A power system controls the produced power output level of the wind turbine to the requested power output level. Moreover, the blade pitch of the rotor is further controlled by a pitch feedback control loop that modifies the pitch value based on a difference between the produced power output level and the requested power output level.

Abstract: A method, a controller and a wind turbine with a controller for controlling the wind turbine in a cluster of wind turbines. Each wind turbine is controlled individually and each windturbine is configured to deliver power to the same utility grid. According to the method a delivery from a first wind turbine is reduced from a present power level to a reduced power level in response to an initial frequency of the utility grid exceeding a first threshold value; and the wind turbine is allowed to continue delivering power at the reduced power level.