A method and associated system for providing grid-forming (GFM) control of an inverter-based resource (IBR) connected to an electrical grid include monitoring the electrical grid for grid events that cause a change in one or both of grid frequency and angle. Via a controller, an active power response of the IBR to the grid event is controlled by changing an angle of the IBR voltage relative to grid voltage in a manner so as to mimic an active power response of an IBR having a certain desired impedance that may similar to or different from a hardware impedance of the IBR itself.

A transition piece (140) for a wind turbine tower (110) is provided, that is configured to be installed on a tower foundation (111) and to carry a tower piece (113). It comprises a high voltage joint (10) with grid input and output terminals (11, 12) and WTG connecting input and output terminals (14, 13). The grid input terminal (11) is configured for receiving and connecting to an array cable (21) from a power grid (20). The WTG connecting output terminal (13) is operatively connected to the grid input terminal (11) for receiving and connecting to an input cable (23) leading to a switchgear (30). The WTG connecting input terminal (14) is configured for receiving and connecting to an output cable (24) from the switchgear (30). The grid output terminal (12) is operatively connected to the WTG connecting input terminal (14) for receiving and connecting to an array cable (22) leading to the power grid (20). Further, installation, testing, connecting and maintenance methods taking advantage of the high voltage joint (10) are provided.

There is provided a method of controlling a wind turbine on starting or running up the wind turbine before the wind turbine is connected to an electrical supply grid or before the wind turbine is connected to the electrical energy supply grid again. The wind turbine has a rotor having a rotor arresting means, at least one rotor blade and at least one blade angle detection sensor for each rotor blade for detecting the blade angle of the rotor blade. The blade angle of the at least one rotor blade is detected by means of the blade angle detection sensor. Unlocking of the rotor arresting means is blocked until the detected at least one blade angle is within a predetermined angle range. In that way it is possible to ensure that the rotor arresting means is released only when the blades are for example in the feathered position.

Aspects of the present invention relate to a method for controlling an amount of reactive current provided from a wind turbine generator to a power grid during an abnormal power grid event, said wind turbine generator comprising a doubly-fed induction generator having a rotor and a stator, and a power converter coupling the rotor to the power grid, the power converter comprising a grid-side inverter, wherein the method comprises the step of balancing the reactive current provided to the power grid between a reactive stator current and a reactive grid-side inverter current, wherein the reactive grid-side inverter current is controlled in accordance with a reactive current capacity of a grid breaker receiving the reactive current provided by the grid-side inverter. Aspects of the present invention also relate to a wind turbine generator being capable of performing the method.

The invention relates to a method for operating a power system of a wind turbine. The power system comprises first and second parallel connected DC-to-AC converters and at least one transformer, where each transformer comprises a primary section connected to a power line, and where the at least one transformer comprises first and second secondary sections connected to outputs of the respective first and second DC-to-AC converters. The method comprises providing a reactive correction reference, changing first and second reactive powers generated by the respective first and second DC-to-AC converters according to the reactive correction reference, so that one of the first and second reactive powers is increased while the other is decreased with amounts corresponding to the reactive correction reference so that the first and second reactive powers are unequal.

Unique systems, methods, techniques and apparatuses of hybrid power plants are disclosed. One exemplary embodiment is a hybrid power plant system including a plurality of hybrid generation units each including an AC collection bus, an AC power source, an AC-AC power converter coupled to the AC power source and AC collection bus, a DC power source, a DC-AC converter coupled to the DC power source and the AC collection bus, an energy storage device, and a power transformer coupled to the AC collection bus and structured to receive AC power from the AC collection bus, step up a voltage of the received AC power, and output medium voltage AC (MVAC) power.

A method and a device for detecting an active power of a wind turbine. The method includes: acquiring a current rotation speed of a rotor of a wind turbine and a current outputted active power; determining an effective wind speed of the wind turbine; determining a maximum active power capable to be captured by the wind turbine at the current rotation speed; determining a maximum active power capable to be outputted by the wind turbine, and determining a release power at which the wind turbine is capable to release a rotation kinetic energy of the wind turbine for a predetermined time at the current rotation speed; and determining the available active power of the wind turbine, based on the maximum active power capable to be outputted, the release power, and the current outputted active power.

A method for controlling a wind power installation includes measuring a grid voltage of an electrical power supply grid, setting a DC-link voltage at a converter of the wind power installation depending on the measured grid voltage and using a first time constant and a second time constant, wherein the first time constant is different than the second time constant.

A method for providing frequency response for a plant coupled to an electric power grid, the plant having an intermittent energy source, comprising: measuring frequency of the power output from the plant and determining a first difference between the measured frequency and a frequency reference; measuring power output from the plant and storing the measured power output as a stored value; while the first difference is within a deadband, determining a second difference as a difference between a power reference and the measured power output; while the first difference indicates over-frequency, determining the second difference as a difference between the stored value and the measured power output; while the first difference indicates under-frequency, setting the second difference equal to the power reference; generating an error by limiting a sum of the first and second differences between error limits; generating a control signal; and, applying the control signal to the source.

A wind powered hydrogen generator with storage that is decoupled from an electric grid. A start-up fuel cell provides power to the generator to energize the generator's field coils, to the pitch adjustable blades to adjust pitch of the blades to maintain rotation rate of the rotor, and to power the yawing motor. Electrolyzers are stacked in the tower to generate hydrogen, which is stored in hydrogen impermeable piping mounted on the tower to receive hydrogen for storage and to provide hydrogen to the start-up fuel cell. The invention can be sited in locations having wind speeds within the operating range of wind speeds, regardless of whether connection can be made to the electric grid.