A method of controlling an induction generator is provided connected to a utility grid, the method including: receiving an actual grid frequency; and controlling rotor windings of the generator by a rotor control signal having a rotor winding reference frequency being set in dependence of the actual grid frequency.

A method for controlling a wind farm, which is operated by means of a wind farm control unit and comprises a multiplicity of wind power installations having wind power installation controllers and being connected to one another via a common wind farm grid, which is connected to an electrical power supply grid of a grid operator by means of a wind farm transformer, comprising the following steps: reception of at least one fault bit at the wind farm control unit, in particular at least one fault bit of the grid operator, deactivation of all external setpoint value specifications at the wind farm control unit apart from those of the grid operator after reception of the fault bit, activation of a closed-loop fault case control implemented in the wind farm control unit after successful deactivation of all external setpoint value specifications apart from those of the grid operator.

A method for controlling a wind power installation is provided. The method includes operating the installation at a normal operating point at which the installation is not operated in a throttled fashion if there is no request for throttling, and operating the installation at a throttled operating point, in response to a throttle request, with output power which is throttled in comparison with the normal operating point. The method includes changing the operation from the throttled operating point to a reserve operating point at which the installation is operated with higher output power in response to a power increase request. The throttled operating point has a higher tip speed ratio than that of the reserve operating point and is positioned on an associated iso-characteristic curve in the λθ diagram having, at the throttled operating point, a negative characteristic curve gradient.

Methods and apparatus for reducing peak power consumption of a grid connected power plant having a plurality of wind turbines. In response to determining that a power production value of the power plant is below a power threshold, one method includes: after a first time delay of a first group of one or more wind turbines, control the first group to operate in a power saving mode for a predefined first power saving period; and after a first time delay of a second group of one or more other wind turbines, control the second group to operate in the power saving mode for a predefined second power saving period. The first time delay of the first group is less than the first time delay of the second group and the power saving mode inhibits a power consuming activity for the wind turbines operating in the power saving mode.

A method for attenuating low-frequency oscillations in an electrical power supply grid by means of a feed device which feeds into the electrical power supply grid, in particular a wind power installation, wherein the electrical power supply grid has a grid voltage and a grid frequency, comprising the following steps: picking up a grid signal having the low-frequency oscillations, splitting a total frequency range of the grid signal in which oscillations to be attenuated are to be expected into a plurality of partial frequency ranges, each having a lower and an upper range frequency, performing in each case one frequency analysis of the grid signal for each partial frequency range in order to identify in each case one or more oscillations having an oscillation frequency in the partial frequency range, if present, identifying a low-frequency oscillation to be attenuated as target oscillation depending on the frequency analyses of all of the partial frequency ranges, detecting the target oscillation at least according to frequency and amplitude and optionally according to phase, determining a setpoint attenuation signal depending on the target oscillation detected according to frequency and amplitude and possibly phase for attenuating the detected target oscillation, generating a setpoint feed signal depending on the setpoint attenuation signal and a basic setpoint signal, and generating and feeding in a feed signal depending on the setpoint feed signal (QE).

A method for operating a wind farm having a plurality of wind power installations is provided. The installations each comprise an aerodynamic rotor, and the rotors each have an aerodynamic characteristic value. The method includes: obtaining a setpoint power value of the wind farm, in particular a setpoint value of the electrical power of the wind farm to be fed in, ascertaining an actual power value of the wind farm as the sum of actual electrical powers of the operated wind power installations, determining a permissibility of a power-reduced operating mode of each of the wind power installations of the wind farm on the basis of the associated aerodynamic characteristic value, and operating the wind power installations of the wind farm such that each operated wind power installation is operated in a permissible operating mode and the ascertained actual power value does not exceed the obtained setpoint power value.

Harmonics of a power output of a power plant at a point of common coupling between the power plant and a utility grid, wherein the power plant comprises a plurality of energy production units. The method comprises determining an electrical characteristic at the point of common coupling; determining the electrical characteristic at an output terminal of each of the energy production units and dispatching a control signal to at least one of the energy production units to control the electrical characteristic at an output terminal of the respective energy production units. The control signal is based on the measurement of the electrical characteristic at the point of common coupling and arranged for damping the harmonic of the power output of the power plant at the point of common coupling, wherein the control signal is determined on the basis of a predetermined prioritizing sequence of said electrical characteristic.

Provided is a method of controlling a wind turbine group having a plurality of wind turbines. Each wind turbine generates electrical power as wind turbine output power for feeding into an electrical supply network. The group feeds a group power output into the network at a grid connection point, and the group power output is substantially formed as the sum of all the turbine power outputs of the group. A maximum group power output is specified for limiting the group power output, a control value for compliance with the maximum group power output is transferred to each wind turbine in the group in order to limit the output power of the respective wind turbine to a maximum value defined by the control value, and a control relationship is determined between potential control values and potential group power outputs using the control relationships and depending on the maximum group power output.

A method for controlling a wind turbine connected to an electrical grid includes receiving, via a controller, a state estimate of the wind turbine. The method also includes determining, via the controller, a current condition of the wind turbine using, at least, the state estimate, the current condition defining a set of condition parameters of the wind turbine. Further, the method includes receiving, via the controller, a control function from a supervisory controller, the control function defining a relationship of the set of condition parameters with at least one operational parameter of the wind turbine. Moreover, the method includes dynamically controlling, via the controller, the wind turbine based on the current condition and the control function for multiple dynamic control intervals.

A method for providing grid-forming control of an inverter-based resource includes receiving a negative-sequence voltage feedback of the inverter-based resource. The method also includes receiving at least one negative-sequence feedback signal of the inverter-based resource. The method also includes determining, via a negative-sequence regulator, one or more control signals indicative of a desired negative-sequence impedance of the inverter-based resource using the at least one negative-sequence feedback signal. Further, the method includes generating, via the negative-sequence regulator, a control command for the inverter-based resource based on the one or more control signals. Moreover, the method includes controlling the inverter-based resource based on the control command to achieve the desired negative-sequence impedance of the inverter-based resource.