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.

A solution to optimally manage those requirements ensuring on the one hand, that the requirements set by the grid operators are appropriately and accurately accomplished at a point of interconnection (POI) and on the other hand, preventing the wind turbines from over fulfilling the requirements, for example, by remaining connected at voltages levels higher or lower than the ones required which, although possible, may cause higher loads and currents in the wind turbines than needed to fulfill the requirements.

A solution to optimally manage those requirements ensuring on the one hand, that the requirements set by the grid operators are appropriately and accurately accomplished at a point of interconnection (POI) and on the other hand, preventing the wind turbines from over fulfilling the requirements, for example, by remaining connected at voltages levels higher or lower than the ones required which, although possible, may cause higher loads and currents in the wind turbines than needed to fulfill the requirements

A method for heating a wind turbine facility includes: charging a DC link of an electrical converter connected with a wind turbine of the wind turbine facility; heating air inside the wind turbine facility with heat generated by a voltage limiting unit interconnected with the DC link, which includes a resistor adapted for dissipating electrical energy into heat for reducing a voltage in the DC link, when the voltage is above a threshold voltage; wherein the voltage limiting unit is controlled, such that the voltage limiting unit generates heat according to settings defined in a controller of the voltage limiting unit. The heating settings are changed based upon commands from a user interface. Furthermore, the DC link is charged by a grid side converter of the wind turbine facility with power from an electrical grid.

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.

Provided are a control method and system for enhancing an endurance capability to an abnormal voltage of a wind turbine generator system. The control method, includes; providing a doubly-fed wind turbine generator system connected to a power grid; detecting a voltage of the power grid, and determining whether the voltage of the power grid has a fault; when the voltage of the power grid has a fault, detecting a voltage of the DC buses, and determining whether the voltage of the DC buses exceeds a limit value; when the voltage of the DC buses exceeds the limit value, performing integrated system coordination control according to an abnormal operating condition mode; and when the voltage of the power grid returns to a normal range, performing integrated system coordination control on the according to a normal operating condition mode.

A method for heating a wind turbine facility includes: charging a DC link of an electrical converter connected with a wind turbine of the wind turbine facility; heating air inside the wind turbine facility with heat generated by a voltage limiting unit interconnected with the DC link, which includes a resistor adapted for dissipating electrical energy into heat for reducing a voltage in the DC link, when the voltage is above a threshold voltage; wherein the voltage limiting unit is controlled, such that the voltage limiting unit generates heat according to settings defined in a controller of the voltage limiting unit. The heating settings are changed based upon commands from a user interface. Furthermore, the DC link is charged by a grid side converter of the wind turbine facility with power from an electrical grid.

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.

A method for feeding electric power into an electric supply network by means of a wind park comprising several wind turbines. The method comprises the steps of feeding the electric power at a network connection point, recording at least one network state parameter at the network connection point by means of a park control unit, checking the supply network for the presence of a transient process and sending, and/or sending at an increased clock rate, the values measured by the park control unit and/or the control values determined by the park control unit to the wind turbines, once the presence of a transient process has been detected.

A wind turbine generator (WTG) is connected to an electricity grid via a switchgear. A control system disconnects the WTG from the grid in the event of a fault and also if the grid voltage falls below its normal value for a predetermined time, to prevent the WTG from being connected when the control system is not functional. A back-up generator is started manually to recharge a battery and supply power to the control system . When the control system is fully functional, the WTG is manually re-connected to the grid. Alternatively, the control system enters a sleep mode during which the grid voltage continues to be monitored. When the grid voltage returns, the control system reverts to its wake mode and draws sufficient power from the battery to become fully functional, at which point the WTG is re-connected to the grid.