A method of operating a hydraulic system of a plant to resume operation from a minimum operating temperature of the plant, the hydraulic system includes a plurality of electronically operated valves, the method including a first stage in which the valves are controlled to cycle fluid from a tank through a bypass valve and directly back to the tank until the temperature of the fluid in the tank has reached a first interim level; and a second stage in which the valves are controlled to cycle fluid from the tank through the pressure lines of the hydraulic system and back to the tank until the temperature of the fluid has reached a desired operating level. Further, a hydraulic system and a wind turbine include a rotor blade pitching arrangement with such a hydraulic system.

An additional hydraulic device for a pitch system of a wind turbine, the additional hydraulic device including a hydraulic motor, a hydraulic accumulator for storing hydraulic energy, a valve unit, a return line and a reservoir. The return line is connected to the reservoir. The valve unit is switchable to a drive switching position, and the hydraulic motor is connected to the hydraulic accumulator in the drive switching position. The energy stored in the hydraulic accumulator drives the hydraulic motor in the drive switching position so that the hydraulic motor delivers an additional force component.

A hub hydraulic assembly for a wind turbine rotor is provided that includes plural support structures distributed circumferentially about a rotation axis of the hub is provided. In a first angular section of the circumferential distribution, a first support structure is provided and in a second different angular section of the circumferential distribution, a second support structure is provided. The first support structure includes at least a first support cantilever having a mounting end configured to be mounted to the hub and a free end, wherein at least one hydraulic component of the hub hydraulic assembly is mounted to the first support cantilever. The second support structure includes at least a second support cantilever having a mounting end configured to be mounted to the hub and a free end, wherein at least one hydraulic component of the hub hydraulic assembly is mounted to the second support cantilever.

A hydraulic device for a pitch system of a wind turbine includes an air separation device which includes a fluid collector having an air accumulation portion, at least one fluid inlet and a fluid outlet portion, wherein a fluid emulsion of air and hydraulic fluid can be introduced into the fluid collector through the at least one fluid inlet. The fluid collector is labyrinth-shaped so that rotation of the air separation device about an axis of rotation causes the air in the fluid emulsion to move through the labyrinth-shaped fluid collector in a direction to the air accumulation portion and the hydraulic fluid in the fluid emulsion to move through the labyrinth-shaped fluid collector in a direction to the fluid outlet portion.

In a first aspect of the present invention there is provided a wind turbine comprising a tower, a nacelle mounted on the tower, and a rotor mounted to the nacelle. The rotor comprises a hub and at least three wind turbine blades. Each blade extends between a root and a tip. Each blade further comprises a connection point located between the root and the tip. The wind turbine further comprises a plurality of blade connecting members, each blade connecting member being connected between corresponding connection points of a pair of wind turbine blades. The wind turbine further comprises a tensioning system for adjusting the tension in each blade connecting member. The tensioning system comprises a plurality of linear actuators, each linear actuator being coupled between the hub and a respective blade connecting member. Each linear actuator is configured to adjust the tension in the blade connecting member.

A hub hydraulic assembly for a wind turbine rotor is provided that includes plural support structures distributed circumferentially about a rotation axis of the hub is provided. In a first angular section of the circumferential distribution, a first support structure is provided and in a second different angular section of the circumferential distribution, a second support structure is provided. The first support structure includes at least a first support cantilever having a mounting end configured to be mounted to the hub and a free end, wherein at least one hydraulic component of the hub hydraulic assembly is mounted to the first support cantilever. The second support structure includes at least a second support cantilever having a mounting end configured to be mounted to the hub and a free end, wherein at least one hydraulic component of the hub hydraulic assembly is mounted to the second support cantilever.

A hydraulic system for the pitch angle adjustment of a rotor blade of a wind turbine) includes a variable displacement pump, a hydraulic accumulator, a dynamic valve, a control valve, a tank and a pitch cylinder. The variable displacement pump is connected to the control valve via a first connecting line and the control valve is connected to the tank via a second connecting line and to a piston side of the pitch cylinder via a third connecting line and to a rod side of the pitch cylinder via a fourth connecting line. In a first switching position, the first connecting line is connected to the third connecting line and in a second switching position, the first connecting line is connected to the fourth connecting line and the second connecting line is connected to the third connecting line.

A hydraulic device for a pitch system of a wind turbine includes an air separation device which includes a fluid collector having an air accumulation portion, at least one fluid inlet and a fluid outlet portion, wherein a fluid emulsion of air and hydraulic fluid can be introduced into the fluid collector through the at least one fluid inlet. The fluid collector is labyrinth-shaped so that rotation of the air separation device about an axis of rotation causes the air in the fluid emulsion to move through the labyrinth-shaped fluid collector in a direction to the air accumulation portion and the hydraulic fluid in the fluid emulsion to move through the labyrinth-shaped fluid collector in a direction to the fluid outlet portion.

In a first aspect of the present invention there is provided a wind turbine comprising a tower, a nacelle mounted on the tower, and a rotor mounted to the nacelle. The rotor comprises a hub and at least three wind turbine blades. Each blade extends between a root and a tip. Each blade further comprises a connection point located between the root and the tip. The wind turbine further comprises a plurality of blade connecting members, each blade connecting member being connected between corresponding connection points of a pair of wind turbine blades. The wind turbine further comprises a tensioning system for adjusting the tension in each blade connecting member. The tensioning system comprises a plurality of linear actuators, each linear actuator being coupled between the hub and a respective blade connecting member. Each linear actuator is configured to adjust the tension in the blade connecting member.