Abstract: A method for operating a power generation system coupled to a power grid during a grid unbalance event, a method for determining an injection current to be supplied into a power grid by a power generation system, and a method for addressing an asymmetric grid fault in a power grid connected to a power generation system are provided. The methods may be carried out based on a reactive or an active power/current priority.

Abstract: A wind turbine generator 1 supplies three-phase a.c. current of variable voltage and variable frequency to two pairs of rectifiers 4a, 4b and 4c, 4d which generate respective d.c. outputs connected to positive, negative and neutral d.c. conductors 6, 7, 8. The outputs from each pair of rectifiers are connected together, and the outputs from the two pairs are connected in series to create a high-voltage d.c. output. Inverters 10a, 10b, 10c, 10d then convert the d.c. power to a.c. at a fixed frequency and voltage suitable for In connection to the mains grid. To reduce the effect of common-mode noise, a capacitor is connected between the 1 neutral conductor 7 and earth, and a respective filter circuit 30 is connected between each of the a.c. outputs of the inverters 10a, 10b, 10c, 10d and earth. To reduce the effect of voltage surges during lightning, a surge protection device is also connected between the neutral d.c. conductor 7 and earth.

Abstract: A method for operating a power generation system coupled to a power grid during a grid unbalance event, a method for determining an injection current to be supplied into a power grid by a power generation system, and a method for addressing an asymmetric grid fault in a power grid connected to a power generation system are provided. The methods may be carried out based on a reactive or an active power/current priority.

Abstract: A method for operating a power generation system coupled to a power grid during a grid unbalance event, a method for determining an injection current to be supplied into a power grid by a power generation system, and a method for addressing an asymmetric grid fault in a power grid connected to a power generation system are provided. The methods may be carried out based on a reactive or an active power/current priority.

Abstract: Method, system, and computer readable medium for determining a fault in a power filter of a wind turbine generator. The method may include the steps of calculating a reactive power consumed by the power filter, and comparing the calculated reactive power to a predefined threshold reactive power to determine the fault.

Abstract: According to an embodiment, a power generation system is provided comprising a power generator; a plurality of converter modules, each converter module having a DC link, wherein the DC link of each converter module is connected to the DC links of the other converter modules of the plurality of converter modules via a fuse associated with the converter module; and a controller configured to, if it is detected that there is a fault in one of the converter modules, disconnect the converter module in which there is a fault from the power generator and connect two or more other converters module of the plurality of converter modules to the power generator and to control the power generation system to supply power to the DC links of the two or more other converter modules such that power is supplied to the converter module in which there is a fault via the fuse associated with the converter module such that the fuse associated with the converter module melts.

Abstract: A method for operating a power generation system coupled to a power grid during a grid unbalance event, a method for determining an injection current to be supplied into a power grid by a power generation system, and a method for addressing an asymmetric grid fault in a power grid connected to a power generation system are provided. The methods may be carried out based on a reactive or an active power/current priority.

Abstract: The invention relates to a method for operating a wind turbine connected to a utility grid during a utility grid disturbance. The method comprises the steps of controlling active current in dependency of the frequency deviation from a reference frequency, and controlling reactive current in dependency of the voltage deviation from a reference voltage. The invention also relates to a wind turbine and wind park.

Abstract: Method, system, and computer readable medium for determining a fault in a power filter of a wind turbine generator. The method may include the steps of calculating a reactive power consumed by the power filter, and comparing the calculated reactive power to a predefined threshold reactive power to determine the fault.

Abstract: A method for controlling a cluster of wind turbines connected to a utility grid includes the steps of determining the frequency of the utility grid, detecting a frequency deviation in the utility grid, and disconnecting the wind turbines at different predefined frequency values above the nominal frequency value. The invention also relates to a method for planning the strategy of a utility grid including a wind turbine cluster connected to the grid and a wind turbine cluster.

Abstract: Method of controlling a wind turbine connected to an electric utility grid during malfunction in the electric utility grid is provided. The method includes the steps of detecting a malfunction in the electric utility grid and operating at least two control units of a power converter in relation to at least one power converter limit value. A control system for a wind turbine connected to a utility grid and a wind turbine is also provided.

Abstract: The invention relates to a method for operating a wind turbine connected to a utility grid during a utility grid disturbance. The method comprises the steps of controlling active current in dependency of the frequency deviation from a reference frequency, and controlling reactive current in dependency of the voltage deviation from a reference voltage. The invention also relates to a wind turbine and wind park.

Abstract: A method for controlling a cluster of wind turbines connected to a utility grid includes the steps of determining the frequency of the utility grid, detecting a frequency deviation in the utility grid, and disconnecting the wind turbines at different predefined frequency values above the nominal frequency value. A method for planning the strategy of a utility grid including a wind turbine cluster connected to the grid and a wind turbine cluster is also contemplated.

Abstract: The invention relates to a method of controlling a wind turbine connected to an electric utility grid during malfunction in said electric utility grid (9). The method comprises the steps of detecting a malfunction in said electric utility grid and operating at least two control units of said power converter (12) in relation to at least one power converter limit value. The invention also relates to a control system for a wind turbine connected to a utility grid and a wind turbine.

Abstract: The present invention relates to a method and an apparatus for controlling a power-grid connected wind turbine generator during grid faults. During grid faults, the stator windings of the wind turbine generator are disconnected from the power grid and impedances for dissipating at least part of the power generated by the wind turbine during grid fault condition are connected to the stator windings. In this way, a certain magnetisation of the generator can be maintained and after removal of the grid fault condition, the generator is synchronised to the power grid and the impedances are disconnected and the stator windings are reconnected to the power grid. In this way, it is possible to keep the wind turbine generator at least partly magnetised during grid faults and thus ready for delivering power to the power grid, as soon as the grid voltage is re-established after the fault.