A tower structure of a wind turbine includes a plurality of tower sections stacked atop each other in an end-to-end configuration along a vertical axis to form the tower structure of the wind turbine at a wind turbine site. Each of the tower sections is formed of at least one first tubular portion and at least one second tubular portion. Further, the first and second tubular portions of each of the plurality of tower sections are concentric with each other. Moreover, the first tubular portion is formed at least in part, of a cementitious material and the second tubular portion is formed of a perforated material having a plurality of holes.

A segment sheet for a stator lamination stack of a generator of a wind turbine, wherein the segment sheet has the shape of a ring segment, having a first radial section, in which recesses are provided for receiving a stator winding, having a second radial section, which is arranged radially adjacent to the first section and which forms a segment of a magnetic yoke of the generator, and having a third radial section, which is arranged radially adjacent to the second section. The proposal is that the third radial section has at least two recesses arranged in an azimuthally spaced manner, which are designed for a positive connection to profiled strips arranged on a stator support ring.

A method for pretensioning a tower of a wind power installation, comprising the steps: providing a tensioning device having an adapter element and/or a foundation arrangement and a tensioning element, and/or an adapter element and/or a foundation arrangement, fastening a lower end of a tensioning element a fastening means of the adapter element, fastening an upper end of a tensioning element to an upper end of the tower, tensioning the tensioning element at the lower end of the tensioning element and/or at the upper end of the tensioning element, wherein the tensioning of the tensioning element is effected by reduction of a clearance between the foundation and the adapter element.

The invention relates to a method for monitoring performance of a multi-rotor wind turbine. According to the method parameter for each of the wind turbine modules of the multi-rotor wind turbine is obtained. The parameters of each of the wind turbine modules are compared, e.g. by means of a comparison parameter determined from the individual parameters. Dependent on the result of the comparison, a performance action is initiated, e.g. for the purpose of further characterization or verification of a deviating parameter determined via the comparison.

A retrofitted wind turbine installation for replacing a prior wind turbine installation includes the foundation of the prior wind turbine installation and a replacement wind turbine supported by the foundation, wherein the tower of the retrofitted wind turbine installation is a cable-stayed tower to reduce the bending loads imposed on the foundation. A method of retrofitting an existing wind turbine installation with a replacement wind turbine includes disassembling at least a portion of the existing wind turbine, assembling a replacement tower to a remaining portion of the existing wind turbine installation, attaching a plurality of stay cables between the tower of the retrofitted wind turbine installation and stay cable foundations, and attaching the replacement energy generating unit to the replacement tower.

A multirotor wind turbine (1) comprising a tower structure (2) and at least one load carrying structure (3), each load carrying structure (3) being arranged to carry two or more energy generating units (5), is disclosed. The wind turbine (1) further comprises a yawing arrangement (6) comprising a first part (9) being fixedly connected to the tower structure (2) and a second part (10) being fixedly connected to at least one of the load carrying structure(s) (3). The first part (9) and the second part (10) are configured to perform rotating movements relative to each other, thereby allowing the load carrying structure (3) to perform yawing movements relative to the tower structure (2). At least one guy wire (7) is connected between an anchoring point (8) at the ground and the first part (9) of the yawing arrangement (6). The invention further provides a yawing arrangement (6) for such a multirotor wind turbine (1).

A wind energy farm (1) comprising at least one first wind turbine (2) and at least one second wind turbine (3) is disclosed. Each wind turbine (2, 3) comprises a tower (7) mounted on a foundation, and at least one rotor (9) with a hub carrying a set of wind turbine blades (10). The at least one first wind turbine (2) is provided with at least three stay cables (4), each stay cable (4) being connected at one end to the tower (7) of said at least one first wind turbine (2) and at the other end to a stay cable foundation. At least one of the stay cable foundations and the foundation of one of said at least one second wind turbines (3) of the wind energy farm (1) are combined into a single combination foundation.

An enclosure with a frequency mixing and absorbing device on an outer surface is provided. The frequency mixing and absorbing device includes a deformable body located on an outer surface of the enclosure, the deformable body includes a flexible body and/or an elastic body, the flexible body is a flexible hollow body or a flexible solid body, the elastic body is an elastic hollow body or an elastic solid body. When the direction of the incoming flow is from left to right, it acts on the deformable body at a windward side, that is, the change of pressure will be converted into the volume change of the deformable body. In this way, the fluctuating energy of the incoming flow can be absorbed and stored by the deformation of the deformable body, and the fluctuating energy is transferred to the volume change.

The wind-wave complementary energy integrated system based on fixed foundation and generation and transmission method thereof pertains to the field of ocean renewable energy utilization, solving the problem of combining the wind and wave energy in a support structure, including a wind turbine, a tower, a wave energy device and a single pile foundation, the wind turbine is connected to the tower, and the single pile foundation is at the bottom of the tower, the single pile foundation is connected to the seabed, and the wave energy device is mounted on the tower near the sea surface. The effect is the renewable energy utilization rate and the energy conversion rate are effectively improved, thus reducing the cost to a certain extent and having high utility.

Provided is a tower section arrangement for a guyed tower of a wind turbine, the tower section arrangement including: a tower section including a wall having an outer surface with a circumference, at least two brackets attached to the outer surface of the wall at different locations on its circumference, and at least two stay cables, wherein each stay cable is connected at its first end to one of the brackets and is configured for connection at its second end to a cable foundation, and wherein an angle (α) between each stay cable and a tangent to the outer circumference at the respective bracket has, in a top view of the erected wind turbine, a value of 90° when the respective stay cable is guyed.