Abstract: A system and method are provided for controlling a wind turbine of a wind farm. Accordingly, a controller prepares a yaw bias correction function based, at least in part, on a yaw offset function, and on wind speed measurement data and wind direction reference data of a wind event acting on at least a portion of the wind farm. The controller also applies the yaw bias correction function based at least in part on position data of a nacelle of the wind turbine, to yaw the nacelle of the wind turbine.

Abstract: A method for operating a wind farm having a string (S1-S3) of wind turbines (100-100d) which are electrically connectable with each other and a grid (510, 550) via power connections (Cab-Cd) is disclosed. Each wind turbine includes a rotor (106) with rotor blades (108), and a power conversion system (118, 210, 238) mechanically connected with the rotor (106). The method includes disconnecting the string (S1-S3) from the grid (510, 550), and identifying a primary wind turbine (100a, 100c) of the disconnected string (S1-S3) which is electrically connectable with at least one secondary wind turbine (100b-10d) of the disconnected string (S1-S3). The power conversion system (118, 210, 238) of the primary wind turbine (100a, 100c) includes a reactive power capability (RPC) that at least matches a reactive power (RP) of a cluster (C1, C11, C12) to be formed by electrically connecting the primary wind turbine (100a, 100c) with the at least one secondary wind turbine (100b-100d) of the disconnected string (S1-S3).

Abstract: A method for operating a wind farm having a string (S1-S3) of wind turbines (100-100c) which are electrically connectable with each other and a grid (510, 550) is disclosed. Each wind turbine includes a rotor (106) with rotor blades (108), a power conversion system (118, 210, 238) mechanically connected with the rotor (106), and at least one auxiliary subsystem (105, 109).

Abstract: A braking assembly of a wind turbine includes a slewing ring bearing, at least one first drive mechanism having a first motor and a first drive pinion that rotationally engages the slewing ring bearing. The first motor is pre-tensioned in a first direction by a first amount of force. The braking assembly also includes at least one second drive mechanism having a second motor and a second drive pinion that rotationally engages the slewing ring bearing. The second motor is pre-tensioned in a second direction with a second amount of force. The first direction and the second direction are opposite of each other and the first amount of force are substantially equal to the second amount of force. Thus, the first and second amounts of force substantially cancel each other while also allowing dithering of at least one of the first and second motors, thereby preventing substantial rotational movement of the slewing ring bearing.

Abstract: A method for controlling a power output of a power generating unit includes receiving at least two measurement data sets from a location of integration of a power generating unit to an electrical grid. Each measurement data set includes a plurality of electrical parameters. The method further includes generating a grid model of the electrical grid based on the at least two measurement data sets. The grid model is characterized by an equivalent grid voltage and an equivalent grid impedance. The method further includes computing a strength value of the electrical grid based on the grid model, using the at least two measurement data sets. The method also includes controlling the power output of a power generating unit based on the strength value of the electrical grid.

Abstract: A system and method are provided for operating a power generating asset having a generator operably coupled to a power grid. The generator having a rotor and a stator. The stator being operably coupled to a transformer, and ultimately to the power grid, via a sync-switch assembly. The sync-switch assembly having a plurality of switching devices electrically coupled in parallel. Accordingly, a controller detects an approach of at least one operating parameter of the power generating asset to a first parameter threshold. In response to detecting the approach of the operating parameter to the first parameter threshold, the controller independently changes an operating state of a first switching device of the plurality of switching devices of the sync-switch assembly. Each switching device of the plurality of switching devices is independently controllable via the controller.

Abstract: A system and method are provided for operating a power generating asset having a generator operably coupled to a power grid. The generator having a rotor and a stator. The stator being operably coupled to a transformer, and ultimately to the power grid, via a sync-switch assembly. The sync-switch assembly having a plurality of switching devices electrically coupled in parallel. Accordingly, a controller detects an approach of at least one operating parameter of the power generating asset to a first parameter threshold. In response to detecting the approach of the operating parameter to the first parameter threshold, the controller independently changes an operating state of a first switching device of the plurality of switching devices of the sync-switch assembly. Each switching device of the plurality of switching devices is independently controllable via the controller.

Abstract: A method for operating a power generation system that supplies real and reactive power to a grid includes receiving a reactive power demand made on the power generation system at an operating state of the power generation system and a grid state. Further, the method includes decoupling reactive power control and voltage control between a generator and a reactive power compensation device so as to reduce an oscillatory response of a reactive power output from the reactive power compensation device and the generator. Moreover, the method includes operating, via a device controller, the reactive power compensation device in a reactive power control mode to generate at least a portion of the reactive power demand.

Abstract: A system of reactive power compensators for a wind farm includes a multi-winding transformer and a plurality of modular reactive power compensators (MVBs). The multi-winding transformer includes a primary winding and a plurality of secondary windings. The primary winding is configured to be coupled to a point of common coupling (POCC) for the wind farm. The plurality of MVBs are each coupled to a corresponding winding of the plurality of secondary windings.

Abstract: A system of reactive power compensators for a wind farm includes a multi-winding transformer and a plurality of modular reactive power compensators (MVBs). The multi-winding transformer includes a primary winding and a plurality of secondary windings. The primary winding is configured to be coupled to a point of common coupling (POCC) for the wind farm. The plurality of MVBs are each coupled to a corresponding winding of the plurality of secondary windings.

Abstract: A wind turbine system is configured to supply real and reactive power to a grid and includes a tower, and a generator within a nacelle configured atop the tower. The generator is connected to a rotor, which is connected to a hub that includes a plurality of turbine blades mounted thereon. A power converter is configured at a location within the tower. A reactive power compensation device is also configured at the location within the tower, the reactive power compensation device operably configured with the power converter so as to provide reactive power in combination with reactive power generated by the power converter.

Abstract: A method for estimating grid strength of a power grid connected to a renewable energy farm having a plurality of renewable energy power systems includes measuring, at least, a voltage, an active power, and a reactive power at a point of interconnection of the renewable energy farm to the power grid. The method also includes determining a sensitivity of the voltage to at least one of the active power or the reactive power at the point of interconnection. Further, the method includes determining the grid strength of the power grid as a function of the sensitivity of the voltage to at least one of the active power or the reactive power at the point of interconnection. In addition, the method includes dynamically determining at least one of an active power command or a reactive power command for the renewable energy farm at the point of interconnection based on the grid strength.

Abstract: A method for operating a wind turbine power system that supplies real and reactive power to a grid includes operating a generator of the wind turbine power system up to a first speed limit. The method also includes monitoring a wind speed at the wind turbine power system. When the wind speed drops below a predetermined threshold, the method includes reducing the first speed limit of the generator to a reduced speed limit of the generator. Further, the method includes operating the generator at the reduced speed limit for as long as the wind speed remains below the predetermined threshold so as to optimize a tip-speed-ratio of the wind turbine power system during low wind speeds, thereby increasing power production of the wind turbine power system at low wind speeds.

Abstract: A method for operating a power generation system that supplies real and reactive power to a grid includes receiving a reactive power demand made on the power generation system at an operating state of the power generation system and a grid state. Further, the method includes decoupling reactive power control and voltage control between a generator and a reactive power compensation device so as to reduce an oscillatory response of a reactive power output from the reactive power compensation device and the generator. Moreover, the method includes operating, via a device controller, the reactive power compensation device in a reactive power control mode to generate at least a portion of the reactive power demand.

Abstract: A method for operating a wind turbine power system that supplies real and reactive power to a grid includes operating a generator of the wind turbine power system up to a first speed limit. The method also includes monitoring a wind speed at the wind turbine power system. When the wind speed drops below a predetermined threshold, the method includes reducing the first speed limit of the generator to a reduced speed limit of the generator. Further, the method includes operating the generator at the reduced speed limit for as long as the wind speed remains below the predetermined threshold so as to optimize a tip-speed-ratio of the wind turbine power system during low wind speeds, thereby increasing power production of the wind turbine power system at low wind speeds.

Abstract: A wind turbine system is configured to supply real and reactive power to a grid and includes a tower, and a generator within a nacelle configured atop the tower. The generator is connected to a rotor, which is connected to a hub that includes a plurality of turbine blades mounted thereon. A power converter is configured at a location within the tower. A reactive power compensation device is also configured at the location within the tower, the reactive power compensation device operably configured with the power converter so as to provide reactive power in combination with reactive power generated by the power converter.

Abstract: A method for estimating grid strength of a power grid connected to a renewable energy farm having a plurality of renewable energy power systems includes measuring, at least, a voltage, an active power, and a reactive power at a point of interconnection of the renewable energy farm to the power grid. The method also includes determining a sensitivity of the voltage to at least one of the active power or the reactive power at the point of interconnection. Further, the method includes determining the grid strength of the power grid as a function of the sensitivity of the voltage to at least one of the active power or the reactive power at the point of interconnection. In addition, the method includes dynamically determining at least one of an active power command or a reactive power command for the renewable energy farm at the point of interconnection based on the grid strength.

Abstract: A method for operating a wind turbine system, and associated system, provides real and reactive power to a grid. The wind turbine system includes a generator with a power converter and an integrated reactive power compensation device. A total reactive power demand (Qcmd) is made on the wind turbine system at a first grid state, and is allocated to generator reactive power (Qg) and compensation device reactive power (Qmvb). A first reactive power droop scheme is determined that includes a reactive power droop value applied to one or both of the control loops for (Qg) and (Qmvb) at the first grid state. Upon detection of a grid fault, the first reactive power droop scheme is changed to a second reactive power droop scheme by changing the reactive power droop values applied to one or both of the (Qg) and (Qmvb) control loops during recovery from the grid fault.

Abstract: A method and associated system for operating a power generation system to provide real and reactive power to a load includes, with a power converter having switching elements, receiving power from a generator and generating the reactive power within an operating range of generator rotor speed. As the generator rotor speed changes and approaches synchronous speed, a control command is generated to decrease a switching frequency of the switching elements in the power converter from a first switching frequency to a second switching frequency, wherein the reactive power output of the power converter is maintained or increased at the second switching frequency.

Abstract: A method is provided for operating a power generation system that supplies real and reactive power to a grid, the power generation system including a generator/power converter, and a reactive power compensation device. A total reactive power demand (Qcmd) made on the power generation system is determined , as well as a maximum reactive power capacity for each of a generator stator-side reactive power (Qs), a generator line-side reactive power (Ql), and reactive power from the reactive power compensation device (Qmvb). Allocation of (Qs), (Ql), and (Qmvb) to supply (Qcmd) is coordinated by prioritizing (Qmvb) as a first source of reactive power, and one or both of (Qs) and (Ql) as a second source of reactive power.