In an installation of a wind turbine on a floating foundation in floating condition and subject to sea-state induced motions, e.g. at the site of an offshore windfarm, use is made of a vessel with a crane arranged on the hull and provided with a hoisting system adapted to support the weight of the wind turbine and suspend the wind turbine from the crane. A heave compensation device compensates for sea-state induced heave motion of the wind turbine mast relative to the mast mounting structure of the floating foundation. Use is made of a mast alignment system configured to engage on the suspended wind turbine, e.g. on the mast of the suspended wind turbine, and to bring and maintain the mast of the wind turbine in alignment with the mounting axis of the floating foundation in order to compensate for sea-state induced motions, at least including tilt motions in one or more vertical planes, of the wind turbine mast relative to the mounting axis of the floating foundation.

An offshore wind turbine includes a ballast adjustable hull. In addition, the offshore wind turbine includes a telescopic tower movably coupled to the hull. The tower has a central axis and comprises a plurality of nested concentrically arranged elongate tubulars. Further, the offshore wind turbine includes a ballast adjustable elevator disposed about the telescopic tower and movably coupled to the hull. The elevator is configured to lift one or more of the plurality of tubulars of the tower axially upward relative to the hull. Still further, the offshore wind turbine includes a nacelle coupled to an upper end of one of the plurality of tubulars of the tower. Moreover, the offshore wind turbine includes a rotor assembly coupled to the nacelle.

Described is a device for placing a component of a wind turbine on a wind turbine tower. The device includes a hoisting frame which is suspended from a hoisting hook of a hoisting means, and which is provided with take-up cables whereby the component is taken up in the hoisting frame. The hoisting frame is embodied such that in a first position of the hoisting frame relative to the hoisting hook the centre of gravity of the taken-up component and a centre of gravity of the hoisting frame are situated on either side of a vertical plane which runs through the hoisting hook and which does not comprise any of the centres of gravity. The invention likewise relates to a method which makes use of the invented device.

A nacelle for a wind turbine includes a nacelle roof and a first wind turbine component, wherein the nacelle roof is configured to cover the first wind turbine component, the nacelle roof including a first sliding section and a second sliding section, wherein the first sliding section and/or the second sliding section is configured to slide over at least a part of the surface of the nacelle roof, wherein the first sliding section and the second sliding section are moveable between a closed position, in which the first wind turbine component is covered by the nacelle roof, and an opened position, resulting in an opening of the nacelle roof through which the first wind turbine component is hoisted.

An apparatus is for performing a part of an operation to install a tower for a wind turbine, wherein the wind turbine has a tower, wherein the apparatus has a travelling car for travelling up and down along the tower of the wind turbine and for carrying an item to be installed as part of the wind turbine, wherein the travelling car has a device for balancing the travelling car, and wherein the device for balancing the travelling car has a weight configured to be movably connected to the travelling car i) for allowing keeping the travelling car balanced under exposure to a force or ii) for avoiding, correcting or reducing a shift in a centre of gravity of the travelling car. Further is disclosed a method of balancing a travelling car for an apparatus for performing at least a part of an operation to install a wind turbine.

The lifting device is presented comprising a lifting yoke comprising fastening means connecting to a crane during operation, a support element comprising a support surface dimensioned to support an area of a unit to be lifted, connecting means securing the lifting yoke to the support element during operation, and at least a part of the support element comprises a transport frame corresponding to a lower frame of a container such as a standard container. The lifting device comprises a packed state and an operational state, and in the packed state the components of the lifting device are configured to fit within the dimensions of a container such as a standard container, and in the operational state the components of the lifting device are configured to operate as a lifting device.

An apparatus is for performing parts of an operation to install a wind turbine, wherein the wind turbine has a tower, wherein the apparatus has a travelling car for travelling up and down along the tower for the wind turbine, and wherein the travelling car has a movable portion of a deck of the travelling car, wherein the movable portion of the deck is configured to carry an item to be installed as part of the wind turbine to a height for installation of the item and for moving the item substantially horizontally into a position for installation of the item when the travelling car is in a vertical position for installation of said item. Further is disclosed a method of installing at least a part of a wind turbine.

A main shaft fixture for fixing a main shaft on a wind turbine during installation and repair work on heavy parts of the wind turbine nacelle, in the case where the fixture is formed of several sections for mounting on stable structural parts in the nacelle, including the nacelle's bottom frame. The main shaft fixture has adjustable pressure mandrels with tap shoes, which cause the fixture to be usable regardless of the turbine main shaft geometry, such that it can be mounted without fixing the rotor. The main shaft fixture also has facilities for mounting of a lightweight crane and a self-hoisting crane with a ground-based winch, respectively, as well as a rotor lock which, in combination with actuators of the main shaft fixture, enables the main shaft and the main shaft bearing to be sufficiently displaced vertically from its bearing in the nacelle to service or replace the bearing.

A main shaft fixture for fixing a main shaft on a wind turbine during installation and repair work on heavy parts of the wind turbine nacelle, in the case where the fixture is formed of several sections for mounting on stable structural parts in the nacelle, including the nacelle's bottom frame. The main shaft fixture has adjustable pressure mandrels with tap shoes, which cause the fixture to be usable regardless of the turbine main shaft geometry, such that it can be mounted without fixing the rotor. The main shaft fixture also has facilities for mounting of a lightweight crane and a self-hoisting crane with a ground-based winch, respectively, as well as a rotor lock which, in combination with actuators of the main shaft fixture, enables the main shaft and the main shaft bearing to be sufficiently displaced vertically from its bearing in the nacelle to service or replace the bearing.

A main shaft fixture for fixing a main shaft on a wind turbine during installation and repair work on heavy parts of the wind turbine nacelle, in the case where the fixture is formed of several sections for mounting on stable structural parts in the nacelle, including the nacelle's bottom frame. The main shaft fixture has adjustable pressure mandrels with tap shoes, which cause the fixture to be usable regardless of the turbine main shaft geometry, such that it can be mounted without fixing the rotor. The main shaft fixture also has facilities for mounting of a lightweight crane and a self-hoisting crane with a ground-based winch, respectively, as well as a rotor lock which, in combination with actuators of the main shaft fixture, enables the main shaft and the main shaft bearing to be sufficiently displaced vertically from its bearing in the nacelle to service or replace the bearing.