Abstract: A method of testing an electrical system of a wind turbine that includes at least one power converter coupled to a generator. The power converter is operable in a power generating mode in which the power converter provides a conversion of electrical power generated by the generator and provides a controllable output of AC electrical power towards a power grid. The method includes operating the wind turbine in a testing mode. Operation in the testing mode includes decoupling the electrical system to be tested from the power grid, operating the power converter as a test condition generator, supplying electrical power to the test condition generator, converting, by the test condition generator, the received electrical power to generate predetermined electrical test conditions, and exposing the electrical system to be tested to the predetermined electrical test conditions. The test condition generator controls one or more electrical characteristics of the electrical test conditions.

Abstract: Provided is an electrolysis arrangement including a plurality of electrolytic units, wherein each electrolytic unit includes an electrolytic cell and an AC-DC power converter configured to provide DC power for that electrolytic cell; a plurality of electrolytic assemblies, wherein each electrolytic assembly includes a number of electrolytic units; at least one wind turbine including an electrical generator with a number of armature windings, wherein each armature winding provides AC power to one electrolytic assembly; and a converter unit controller configured to regulate the AC-DC power converters of the electrolytic units on the basis of the power output of an electrical generator. A method of operating such an electrolysis arrangement is also provided.

Abstract: A method for operating at least one wind turbine is provided, the wind turbine being electrically coupled to a power-to-gas converter and an electric grid, wherein a control unit determines a power level for the power generated by at least one generator of the at least one wind turbine and at least partially feeds the generated power to the power-to-gas converter when the determined power level reaches or exceeds a given lower threshold value, wherein the amount of power fed to the power-to-gas converter is kept constant when the determined power level reaches or exceeds a given upper threshold value.

Abstract: Provided is an electrolysis arrangement including a plurality of electrolytic units, wherein each electrolytic unit includes an electrolytic cell and an AC-DC power converter configured to provide DC power for that electrolytic cell; a plurality of electrolytic assemblies, wherein each electrolytic assembly includes a number of electrolytic units; at least one wind turbine including an electrical generator with a number of armature windings, wherein each armature winding provides AC power to one electrolytic assembly; and a converter unit controller configured to regulate the AC-DC power converters of the electrolytic units on the basis of the power output of an electrical generator. A method of operating such an electrolysis arrangement is also provided.

Abstract: A method for controlling the operation of a wind turbine which includes a mechanical drive train, an electric generator being mechanically connected to the drive train, and a power converter being electrically connected to the generator is provided. The method comprises (a) determining a frequency of an AC output voltage signal provided by the power converter; (b) recognizing, whether there has been a modification of the determined frequency with respect to a previously determined frequency, which modification is larger than a given threshold; (c) if the modification of the determined frequency is larger than the given threshold, changing a power reference signal for the wind turbine; (d) providing the changed power reference signal to a controller of the wind turbine; and (e) controlling the operation of the wind turbine on the basis of the changed power reference signal.

Abstract: A power supply arrangement adapted to provide auxiliary power to a wind farm that feeds into a HVDC transmission link is provided. The power supply arrangement has an auxiliary power supply to deliver auxiliary power (Paux) to the wind farm; a backfeed control for initiating provision of a backfeed voltage on the HVDC link during a wind farm downtime; a backfeed switch to close a DC current path between the HVDC link and the auxiliary power supply; and a power converter for converting the backfeed voltage into auxiliary power (Paux). A wind farm arranged to feed into a HVDC transmission link is also provided, having such a power supply arrangement for providing auxiliary power (Paux) to the wind farm during a wind farm downtime. A method of providing auxiliary power (Pbackfeed) to a wind farm during a wind farm downtime is also provided.

Abstract: A method for controlling the operation of a wind turbine which includes a mechanical drive train, an electric generator being mechanically connected to the drive train, and a power converter being electrically connected to the generator is provided. The method comprises (a) determining a frequency of an AC output voltage signal provided by the power converter; (b) recognizing, whether there has been a modification of the determined frequency with respect to a previously determined frequency, which modification is larger than a given threshold; (c) if the modification of the determined frequency is larger than the given threshold, changing a power reference signal for the wind turbine; (d) providing the changed power reference signal to a controller of the wind turbine; and (e) controlling the operation of the wind turbine on the basis of the changed power reference signal.

Abstract: An electric assembly for electrically connecting at least one wind turbine being located off-shore with an electric subsea cable being connected to an on-shore power grid is provided. The electric assembly has (a) a transformer for transforming a first voltage level being provided by the at least one wind turbine to a second voltage level of the subsea cable, and (b) an external equipment being electrically and mechanically connected to the transformer for controlling an operation of at least the transformer. The transformer and the electric equipment are formed by a preinstalled package, which can be mechanically handled as a single piece. Further, a wind turbine having such an electric assembly, a wind turbine cluster having such a wind turbine, and a method for mounting such an electric assembly to a tower of a wind turbine are provided.

Abstract: A converter station for the transmission of electrical power includes a converter with a DC connection terminal and an AC connection terminal, and at least one transformer connected to the AC connection terminal. In order to render the converter station as cost-effective as possible, the station is distributed over at least two independent supporting structures.

Abstract: An electrical yaw drive for a wind turbine is described, wherein the wind turbine includes a wind turbine nacelle and a wind turbine tower. The electrical yaw drive has an asynchronous motor, an excitation capacitor bank and dump loads, wherein the excitation capacitor bank and the dump loads are electrically connectable to windings of the asynchronous motor. Furthermore, a wind turbine with such an electrical yaw drive and a method for operating such a wind turbine are described.

Abstract: A power supply arrangement adapted to provide auxiliary power to a wind farm that feeds into a HVDC transmission link is provided. The power supply arrangement has an auxiliary power supply to deliver auxiliary power (Paux) to the wind farm; a backfeed control for initiating provision of a backfeed voltage on the HVDC link during a wind farm downtime; a backfeed switch to close a DC current path between the HVDC link and the auxiliary power supply; and a power converter for converting the backfeed voltage into auxiliary power (Paux). A wind farm arranged to feed into a HVDC transmission link is also provided, having such a power supply arrangement for providing auxiliary power (Paux) to the wind farm during a wind farm downtime. A method of providing auxiliary power (Pbackfeed) to a wind farm during a wind farm downtime is also provided.

Abstract: An electric assembly for electrically connecting at least one wind turbine being located off-shore with an electric subsea cable being connected to an on-shore power grid is provided. The electric assembly has (a) a transformer for transforming a first voltage level being provided by the at least one wind turbine to a second voltage level of the subsea cable, and (b) an external equipment being electrically and mechanically connected to the transformer for controlling an operation of at least the transformer. The transformer and the electric equipment are formed by a preinstalled package, which can be mechanically handled as a single piece. Further, a wind turbine having such an electric assembly, a wind turbine cluster having such a wind turbine, and a method for mounting such an electric assembly to a tower of a wind turbine are provided.

Abstract: A transmission system and a method for transmitting electrical power which has been produced by at least one off-shore wind turbine to a utility grid being located on-shore is provided. The transmission system has (a) an off-shore transformer, which is connectable to the at least one wind turbine and which is configured for changing a first AC voltage level provided by the at least one wind turbine to a second AC voltage level, (b) a subsea AC transmission cable having an off-shore input end and an on-shore output end, wherein the input end is connected to the off-shore transformer, and (c) a compensation unit for compensating at least partially a reactive power being produced within the subsea AC transmission cable, wherein the compensation unit is electrically coupled to the subsea AC transmission cable at a node being located in between the off-shore input end and the on-shore output end.

Abstract: A power generation system is provided. The power generation system including a power generation unit operable to supply electrical power to an utility system; a synchronous machine coupled to the utility system; a grid measurement device arranged for measuring the current and power that is exchanged between the synchronous machine and the utility system; a controller for adjusting the output power of the power generation unit as a function of the power and current that is measured by the grid measurement device; and a communication link between the grid measurement device, controller and/or the power generation unit. The power generation unit is configured to provide current and power to the utility system as a function of the power and current that is measured by the grid measurement device.

Abstract: A control device, method, and computer program for a wind park are provided, the wind park having a plurality of wind turbines for generating electric power, wherein the wind turbines are electrically interconnected by a wind park grid. The control device includes (a) a determining unit for determining whether a wind park load for consuming electric power from the wind park grid is to be enabled, (b) a calculating unit for calculating a power reference value for each of the plurality of wind turbines, the power reference value being indicative of the amount of power which the corresponding wind turbine should produce, and (c) a transmitting unit for transmitting the calculated power reference values to the corresponding wind turbines, wherein, if the determining unit has determined that the wind park load is to be enabled, at least one of the power reference values calculated by the processing unit is negative.

Abstract: A power interchange system for interchanging electric energy between a battery and an electric grid is provided The power interchange system includes a rectifier unit for converting alternating current of the electric grid into direct current for charging the battery; a grid measurement device for measuring an electric parameter of the electric grid, and a controller unit for adjusting the direct current for the charging the battery as a function of the electric parameter of the electric grid. Moreover a method for interchanging electric energy between a battery and an electric grid is provided.

Abstract: A fault-ride-through method is provided. The method includes detecting a voltage dip on a power line transmitting electric power. If a voltage dip is detected, the method includes reducing an active current and/or an active power to a specific value, which active current and/or active power is fed by a power generating unit at a feeding point into a power network having a plurality of power lines. Further, a converter of a power generating unit is provided, that is capable of implementing the fault-ride-through method. The power generating unit may be a part of a wind turbine in a wind farm.

Abstract: An electrical yaw drive for a wind turbine is described, wherein the wind turbine includes a wind turbine nacelle and a wind turbine tower. The electrical yaw drive has an asynchronous motor, an excitation capacitor bank and dump loads, wherein the excitation capacitor bank and the dump loads are electrically connectable to windings of the asynchronous motor. Furthermore, a wind turbine with such an electrical yaw drive and a method for operating such a wind turbine are described.

Abstract: A wind turbine including a rotor mechanically coupled with a wind turbine generator for transforming mechanical power into electrical power, the generator including a generator output for putting out the electrical power, a wind farm output node being adapted to be electrically coupled with a utility grid, a converter including at least one electric motor with a stator and a rotor and a converter generator with a stator and a rotor the stator of the motor being electrically coupled with the generator output and the stator of the converter generator being electrically coupled with the wind farm output node and the rotor of the motor and the rotor of the converter generator being mechanically coupled with each other.

Abstract: A fault-ride-through method is provided. The method includes detecting a voltage dip on a power line transmitting electric power. If a voltage dip is detected, the method includes reducing an active current and/or an active power to a specific value, which active current and/or active power is fed by a power generating unit at a feeding point into a power network having a plurality of power lines. Further, a converter of a power generating unit is provided, that is capable of implementing the fault-ride-through method. The power generating unit may be a part of a wind turbine in a wind farm.