CN109356797B

CN109356797B - Tower drum structure, offshore wind generating set and installation method thereof

Info

Publication number: CN109356797B
Application number: CN201811622688.1A
Authority: CN
Inventors: 王培显; 丛欧; 郝华庚; 冯玉江
Original assignee: Beijing Tianbin High Tech Wind Power Technology Co ltd
Current assignee: Beijing Tianbin High Tech Wind Power Technology Co ltd
Priority date: 2018-12-28
Filing date: 2018-12-28
Publication date: 2022-09-13
Anticipated expiration: 2038-12-28
Also published as: CN109356797A

Abstract

The invention provides a tower drum structure, an offshore wind generating set and an installation method of the offshore wind generating set. A tower section of thick bamboo structure for offshore wind generating set includes tower section of thick bamboo basis, concrete tower section of thick bamboo section and the steel tower section of thick bamboo that from the bottom up installed in proper order, and tower section of thick bamboo structure still includes: the concrete transition section is installed between the concrete tower barrel section and the tower barrel foundation and is provided with a barrel shape with the sectional area gradually increasing from top to bottom, wherein the concrete transition section is provided with a curved bus with non-constant curvature, and the sectional area of the bottom of the concrete transition section is more than 2 times of that of the top of the concrete transition section. By adopting the tower drum structure, the cost of the tower drum structure of an offshore wind power construction project can be obviously reduced while providing robust support, and the durability of the tower drum structure is improved by fully utilizing the waterproof and anticorrosive characteristics of concrete, so that the offshore wind power generator set can be ensured to safely, reliably and stably operate.

Description

Tower drum structure, offshore wind generating set and installation method of offshore wind generating set

Technical Field

The present disclosure relates to the field of wind power generation, and more particularly, to a tower structure, an offshore wind turbine generator set, and a method of installing an offshore wind turbine generator set.

Background

At present, the development of offshore wind power has entered a brand new period. In an established offshore wind farm, a steel tower, a concrete tower or a steel-concrete tower (including a steel tower section and a concrete tower section) is often used as a supporting structure by using a single-pile foundation, a gravity foundation, a jacket foundation and other types of foundation combination. The tower cylinder structures are slow to install and long in offshore operation time, so that the use cost of large hoisting equipment is increased, and the single unit construction cost is increased. In addition, in order to prolong the service life of the tower drum, the tower drum needs to be subjected to corrosion prevention and water prevention treatment, so that the manufacturing cost of a single unit is further increased.

Disclosure of Invention

Therefore, an object of the present invention is to provide a tower structure for an offshore wind turbine generator system, which can reduce the cost of the tower structure and can provide stable support.

According to one aspect of the invention, the tower structure for the offshore wind generating set comprises a tower foundation, a concrete tower barrel section and a steel tower barrel section which are sequentially installed from bottom to top, and further comprises: the concrete transition section is installed between the concrete tower barrel section and the tower barrel foundation and is provided with a barrel shape with the sectional area gradually increasing from top to bottom, wherein the concrete transition section is provided with a curve type bus with non-constant curvature, and the sectional area of the bottom of the concrete transition section is more than 2 times of that of the top of the concrete transition section.

Preferably, the curvature of the curved busbar may increase gradually from top to bottom or increase gradually and then decrease gradually.

Preferably, the cross-sectional area of the bottom of the concrete transition section may be 6 times or less the cross-sectional area of the top.

Preferably, the concrete transition section may be circular in cross-section, the top diameter of the concrete transition section may be in the range of 8m to 15m, the bottom diameter of the concrete transition section may be in the range of 20m to 35m, and the height of the concrete transition section may be in the range of 20m to 40 m.

Preferably, the concrete transition section may have a polygonal cross section.

Preferably, the tower base may be circular in cross-section, and the diameter of the tower base may be in the range of 30m to 45 m.

Preferably, the height of the concrete tower tube section can account for 30% -70% of the sum of the heights of the steel tower tube section and the concrete tower tube section.

Preferably, the tower structure may further comprise a pre-stressed portion distributed in the cylinder wall of the concrete transition section and the cylinder wall of the concrete tower cylinder section, an upper end of the pre-stressed portion may be anchored at a position of the steel tower cylinder section connected with the concrete tower cylinder section, and a lower end of the pre-stressed portion may be anchored on the tower foundation.

Preferably, the pre-stressed portion may be an integral pre-stressed tendon, or may include a first pre-stressed tendon and a second pre-stressed tendon, an upper end of the first pre-stressed tendon may be anchored at a position of the steel tower section connected with the concrete tower section, a lower end of the second pre-stressed tendon may be anchored on the tower foundation, and both a lower end of the first pre-stressed tendon and an upper end of the second pre-stressed tendon are anchored on an inner surface of the concrete transition section.

Preferably, the wall thickness of the concrete transition section connected to the concrete tower section may become gradually thinner from top to bottom, wherein the concrete tower section may be a prefabricated concrete component.

Preferably, the tower base may be a suction tower base or a gravity base.

According to another aspect of the invention, there is also provided an offshore wind turbine assembly comprising a tower structure as described above.

According to a further aspect of the invention, there is also provided a method of installing an offshore wind energy plant as described above, the method comprising: pouring concrete transition sections on the tower drum foundation by using concrete; after the concrete strength of the concrete transition section reaches the design strength, dragging the tower barrel foundation and the concrete transition section into a parking area; hoisting the concrete tower drum section to the concrete transition section, and adjusting the water discharge of the tower drum foundation to achieve balance; and hoisting the steel tower barrel section to the concrete tower barrel section, and adjusting the water discharge of the tower barrel foundation to achieve balance.

Preferably, the method may further comprise: after the concrete strength of the concrete transition section reaches the design strength, installing a part of the prestressed part in the concrete transition section; after the concrete tower section has been hoisted onto the concrete transition section, another part of the prestressing part is installed in the concrete tower section.

Preferably, the method may further comprise: installing and debugging other parts of the offshore wind generating set in the region to be moored after the steel tower barrel section is installed; and integrally dragging the offshore wind generating set to go out of the port to a machine position for sinking and installation.

By adopting the tower drum structure, stable and robust support can be provided, the cost of the tower drum structure of an offshore wind power construction project can be obviously reduced, the waterproof and anticorrosion properties of concrete are fully utilized to improve the durability of the tower drum structure, so that the requirement of continuous reduction of the engineering construction cost of the tower drum structure of a high-power offshore wind generating set is met, and the offshore wind generating set is ensured to operate safely, reliably and stably.

In addition, by adopting the installation method to install the tower drum structure, the tower drum foundation and the concrete transition section are integrally dragged to the region to be moored after being assembled at the wharf, so that the installation speed can be increased, the offshore operation time can be shortened, and the use of large-scale equipment can be reduced.

Drawings

The above and other objects, features and advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which:

FIG. 1 is a schematic illustration of a tower construction according to a first embodiment of the present invention, wherein the concrete transition segments have parabolic generatrices;

FIG. 2 is a cross-sectional view taken along line A-A of FIG. 1 showing pre-stressed holes formed in the wall of the concrete transition section;

FIG. 3 is a diagram of an integrated tendon installed in the prestressed hole shown in FIG. 2;

FIG. 4 is a cross-sectional view taken along line A-A in FIG. 1, illustrating a pre-stressed hole formed in the barrel wall of the concrete transition and first and second anchors formed on the inner surface of the concrete transition;

FIG. 5 is a diagram of a first tendon and a second tendon installed in the prestressed hole shown in FIG. 4 and fixed on the inner surface of the concrete transition section by a first anchor and a second anchor;

FIG. 6 is a schematic illustration of a tower construction according to a second embodiment of the present invention, wherein the concrete transition segment has an elliptical curvilinear bus bar;

FIG. 7 is a schematic illustration of a tower construction according to a third embodiment of the present invention, wherein the concrete transition segment has spline-type busbars;

FIG. 8 is a schematic view of a tower construction according to a fourth embodiment of the present invention, wherein the concrete transition segment has a segmented curvilinear bus bar.

The reference numbers illustrate:

10: tower base, 20: concrete tower section, 201: door, 30: steel drum sections, 40-1, 40-2 and 40-3: concrete transition section, 50: prestressed portion, 51: prestressed hole, 52: integral type prestressing tendons, 53: first tendon, 531: first anchor, 54: second tendon, 541: a second anchor.

Detailed Description

Embodiments in accordance with the present invention will now be described in detail with reference to the drawings, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to like elements throughout.

Referring to fig. 1, 6 to 8, the tower structure for offshore wind turbine may be in the form of a steel-concrete tower combined with a tower foundation, i.e. the tower structure comprises a tower foundation 10, a concrete tower section 20 and a steel tower section 30, which are installed in sequence from bottom to top. As shown in fig. 1, the tower structure according to the exemplary embodiment of the present invention further includes a concrete transition section 40, the concrete transition section 40 being installed between the concrete tower section 20 and the tower base 10 and having a cylindrical shape with a sectional area gradually increasing from top to bottom, wherein the concrete transition section 40 has a curved generatrix of a non-constant curvature and the sectional area of the bottom of the concrete transition section 40 is more than 2 times the sectional area of the top.

Further, in an embodiment according to the present invention, the curvature of the curved bus bar may gradually increase from top to bottom or gradually increase and then gradually decrease, so that the increase rate of the cross-sectional area of the concrete transition section 40 gradually increases from top to bottom. In particular, fig. 1, 6-8 show examples of curved bus bars having a non-constant curvature. The concrete transition sections 40 of the tower structure shown in FIG. 1 and the concrete transition section 40-1 of the tower structure shown in FIG. 6 have parabolic and elliptical curved generatrices, respectively, which both increase in curvature from top to bottom. The concrete transition section 40-2 of the tower structure according to the third embodiment of the present invention shown in fig. 7 has spline-type generatrices, and the curvature of the spline-type generatrices may be gradually increased from top to bottom or gradually increased and then gradually decreased. In addition, the concrete transition section 40-3 of the tower structure according to the fourth embodiment of the present invention shown in fig. 8 has a sectional type curved bus bar having an upper portion, a middle portion and a lower portion, the upper and lower portions may be straight lines or curves having a small curvature, and the middle portion is a curve having a large curvature, so that the curvature of the sectional type curved bus bar is gradually increased and then gradually decreased from the top to the bottom. Alternatively, the curvature of the curved bus bar may be in the range of 1/10 to 1/200, e.g., 1/11 to 1/34, 1/36 to 1/59, or 1/61 to 1/200.

In the case where the concrete transition section 40 has a curved generatrix, the concrete transition section 40 may have a trumpet shape (circular in cross section) or a frustum shape (polygonal in cross section) with concave arc-shaped sides. For example, the concrete transition section 40 may have a polygonal cross-section with rounded corners that avoid stress concentrations and erosion by seawater impingement, as compared to sharp chamfers.

Furthermore, the ratio of the bottom cross-sectional area to the top cross-sectional area of the concrete transition section 40 may be in the range of 1.5 to 20 to ensure that robust support is provided. The ratio of the bottom to top cross-sectional areas of the concrete transition section 40 and the height of the tower structure above and below sea level are determined by taking into account the plant power and wind resource conditions. The ratio of the bottom cross-sectional area to the top cross-sectional area of the concrete transition section 40 is preferably between 2 and 6, as determined by experimental certification and computational analysis. Generally, the greater the unit power, the greater the ratio. However, embodiments according to the present invention are not limited thereto, and the ratio of the bottom cross-sectional area to the top cross-sectional area of the concrete transition section 40 may also be 3, 4, 5, 7, 8, 10, 12, 15, or the like.

In addition, the height of the concrete transition section 40 above sea level sets a certain safety zone according to the highest height of the splash zone to ensure that the connection location between the concrete drum section 20 and the concrete transition section 40 (as will be described in detail below for the embodiment of fig. 2-3) or the first and second anchors 531 and 541 (as will be described in detail below for the embodiment of fig. 4-5) is above sea level. Preferably, the connection between the concrete tower section 20 and the concrete transition section 40 is located 1.5m to 2.5m above the highest height of the splash zone. Furthermore, the height of the concrete transition section 40 between the sea level and the tower foundation 10 is determined according to the water depth of the wind turbine installation site.

Taking a certain high-power offshore wind generating set as an example, the sizes of all parts of the tower drum structure are as follows: the diameter of the tower foundation 10 may be in the range of 30m to 45m, preferably 35 m; the height may be in the range of 8m to 15m, preferably 10 m. The height of the concrete transition section 40 may be in the range of 20m to 40m, preferably 22.2 m; the top diameter may be in the range of 8m to 15m, preferably 10.36 m; the diameter of the bottom may be in the range of 20m to 35m, preferably 24 m.

In addition, in order to establish a strong connection strength between the bottom of the concrete transition section 40 and the tower foundation 10, the diameter of the bottom of the concrete transition section 40 may be only 8m to 12m smaller than the diameter of the tower foundation 10, and the wall thickness of the cylindrical wall of the concrete transition section 40 may also gradually increase in the top-to-bottom direction.

Additionally, the upper cross-section of the concrete transition section 40 may matingly interface with the lower cross-section of the concrete tower section 20 to facilitate securing the two together. For example, the upper portion of the concrete transition section 40 has a cylindrical portion with a circular cross section, and the cylindrical portion is matched and butted with the circular cross section of the lower portion of the concrete tower tube section 20. Preferably, the wall thickness of the portion of the concrete transition section 40 that is connected to the concrete tower segment 20 is tapered from top to bottom to increase the load bearing capacity of the connection location.

The heights of the steel tower barrel section 30 and the concrete tower barrel section 20 are determined according to the wind resource condition, wherein the height of the concrete tower barrel section 20 can account for 30% -70% of the sum of the heights of the steel tower barrel section 30 and the concrete tower barrel section 20.

Further, the tower structure may further include a prestressed portion 50, an upper end of the prestressed portion 50 is anchored at a position of the steel tower segment 30 connected to the concrete tower segment 20, and a lower end of the prestressed portion 50 is anchored on the tower foundation 10. The prestressed portion 50 applies prestress to the tower foundation 10, the concrete transition section 40, the concrete tower section 20 and the steel tower section 30, so that all parts of the tower structure can be connected together to provide a supporting structure with stronger structural rigidity and more stable and reliable structure for the offshore wind turbine.

In addition, in order to install the prestressed portion 50 in the tower structure, prestressed holes 51 are formed in the cylinder walls of the concrete transition sections 40 and the concrete tower sections 20 in the top-to-bottom direction, so that the prestressed portion 50 may extend through the prestressed holes 51 to prestress the tower structure.

Fig. 1, 6 to 8 only schematically show that the prestressed portion 50 extends continuously from the steel tower segment 30 to the tower foundation 10. In the embodiment according to the present invention, the prestressed portion 50 may be an integral tendon or a two-segment tendon. Specific structures of the two kinds of prestressed tendons will be described below with reference to fig. 2 to 5.

Fig. 2 to 3 illustrate an embodiment in which an integrated tendon 52 is installed in a prestressed hole 51. Specifically, as shown in fig. 2, 24 prestressed holes 51 spaced at the same angular intervals are formed in the cylinder wall of the concrete transition section 40 in the circumferential direction. In addition, 24 prestressing holes (not shown) are correspondingly formed in the wall of the concrete tower segment 20. The integrated pre-stressed tendons 52 pass through these pre-stressed holes 51 (as shown in fig. 3) and are anchored at their upper and lower ends to the location where the steel drum segments 30 are connected to the concrete drum segments 20 (typically the connection flange) and the tower foundation 10, respectively, to fix the tower foundation 10, the concrete drum segments 20, the concrete transition segment 40 and the steel drum segments 30 together. The integrated prestressed tendons 52 are suitable for the condition that the height of the concrete tower tube section 20 and the concrete transition section 40 is smaller, and can provide stronger rigidity or prestress strength.

Fig. 4 to 5 illustrate an embodiment in which two-stage prestressing tendons are installed in the prestressing holes 51. Specifically, as shown in fig. 4, 24 prestressed holes 51 spaced at the same angular intervals are formed in the cylinder wall of the concrete transition section 40 in the circumferential direction. In addition, 24 prestressed holes (not shown) are also correspondingly formed in the wall of the concrete tower segment 20. The two-stage tendon includes a first tendon 53 and a second tendon 54 passing through the prestressing hole 51. The first pre-stressing tendons 53 are anchored at their upper ends to the steel tower section 30 at the location where it is connected to the concrete tower section 20 (typically a connection flange) and at their lower ends to the inner surface of the concrete transition section 40 by first anchors 531 near the location where the concrete transition section 40 is connected to the concrete tower section 20 (as shown in fig. 5). The second tendon 54 is anchored at its lower end to the tower foundation 10 and at its upper end to the lower end of the first tendon 53 in a similar position, but the second anchor 541 and the first anchor 531 are spaced apart in the circumferential direction of the tower structure to prevent the first tendon 53 and the second tendon 54 from interfering with each other. Although it is shown in fig. 5 that the first tendons 53 and the second tendons 54 cross each other, it can be seen from the top view of the tower structure (see fig. 4) that the first anchors 531 and the second anchors 541 are spaced apart in the circumferential direction, so that the first tendons 53 and the second tendons 54 do not interfere with each other.

Although only the embodiment of the integrated tendon and the two-stage tendon is described in fig. 2 to 5, the pre-stress portion 50 may also be a three-stage tendon, a four-stage tendon, or a multi-stage tendon having more stages according to the embodiment of the present invention without being limited thereto. The number of segments of the tendon included in the prestressed portion 50 may vary according to the heights of the concrete tower segment 20 and the concrete transition segment 40 and the prestress strength or rigidity requirement of the tower structure. Generally speaking, the segmented tendons are suitable for the case where the height of the concrete tower segment 20 and the concrete transition segment 40 is high, and the installation of the tendons can be facilitated.

Further, the pre-stressed apertures 51 and the number of pre-stressed tendons passing through each pre-stressed aperture 51 may vary depending on the size (e.g., diameter and/or height) and structural rigidity requirements of the tower structure. Generally, the number of the pre-stress holes 51 may be greater than or equal to 4, and the number of the pre-stress bundles passing through each pre-stress hole 51 may be greater than or equal to 1. Further, each prestressing strand may be composed of one or more prestressing strands, or of one or more parallel steel stranded rope bodies. In addition, although it is illustrated in fig. 2 and 4 that 24 pre-stressed holes 51 are spaced at the same angular interval, embodiments according to the present invention are not limited thereto, the number of pre-stressed holes 51 may be greater or less, and the pre-stressed holes 51 may be spaced at different angular intervals. For example, more pre-stressed holes 51 may be provided on the windward side of the tower structure to install more pre-stressed portions 50, thereby being able to withstand stronger loads.

In addition, in order to facilitate the entering and exiting of the tower structure by the staff, a door opening is opened at the lower part of the concrete tower section 20 (i.e., the part above the height of the splash zone), and a door 201 is installed on the door opening. It should be noted that the concrete column section 20 is provided with a door opening at a position avoiding the prestressing hole 51 for installing the prestressing portion to prevent the prestressing tendons from being broken. However, if the concrete column section 20 is opened at a position where the door opening is not avoidable from the prestressing hole 51, the disconnected prestressing tendons may be anchored on the inner surface of the concrete column section 20 by the anchors as described above.

Preferably, the tower foundation 10 may be a suction drum foundation, a suction caisson, or a gravity-type foundation, or may be another type of foundation (e.g., a jacket foundation or a multi-pile type foundation) capable of installing the concrete transition piece 40 to accommodate the foundation environment at sea.

Furthermore, according to the above embodiments of the present invention, the tower structure as described above is suitable for a wind turbine generator system. A method of installing a wind turbine generator set according to the present invention will be described below with reference to fig. 1 to 5, the method including:

pouring concrete into the transition section 40 on the tower foundation 10;

after the concrete strength of the concrete transition section 40 reaches the design strength, dragging the tower foundation 10 and the concrete transition section 40 into a parking area;

hoisting the concrete tower barrel section 20 to the concrete transition section 40, and adjusting the water displacement of the tower barrel foundation 10 to achieve balance;

the steel tower barrel section 30 is hoisted onto the concrete tower barrel section 20 while the displacement of the tower foundation 10 is adjusted to achieve equilibrium.

The method may further comprise: after the concrete strength of the concrete transition section 40 reaches the design strength, installing a part of the prestressed part 50 in the concrete transition section 40; after the concrete tower segment 20 is hoisted onto the concrete transition piece 40, another part of the prestressed portion 50 is installed in the concrete tower segment 20. Preferably, after the first section of steel tower section 30 is installed, it is ensured that the prestressed portion 50 is completely built.

The method may further comprise: installing and commissioning other components of the wind turbine generator set (e.g., main frame, hub, blades, etc.) in the area to be moored after installation of the steel tower section 30; and integrally dragging the wind generating set to go out of the port to a machine position point for sinking and installation.

The above-described mounting method is also applicable to the structure shown in fig. 6 to 8.

In the above embodiments according to the present invention, the tower foundation 10 and the concrete tower segment 20 may be prefabricated production components, and particularly, the tower foundation 10 may be integrally towed into a parking area after being prefabricated and connected in a factory or a dock, and after the wind turbine generator set is integrally installed and debugged, the wind turbine generator set is integrally towed out of a port and sinks to a machine site, so that a method for quickly installing an integral tower at the machine site is implemented, thereby shortening the time for installing a tower structure (particularly, the time for offshore operation) and reducing the use of large-scale hoisting equipment.

Compared with a traditional cone tower structure in a frustum form or a transition structure with an arc bus of constant curvature, under the condition that the sectional area of the bottom of the concrete transition section is designed under the same load and is not changed, the structure of the concrete transition section is designed in the above mode, the increasing rate of the sectional area of the concrete transition section is gradually increased from top to bottom, so that the contact area of the concrete transition section and a tower foundation is increased, the design margin of the top size of the concrete transition section is increased, and more reliable and robust support is provided for the concrete tower section, the steel tower section and other parts of the wind generating set. In addition, the concrete transition section is arranged between the concrete tower drum section and the tower drum foundation, so that the low-cost, waterproof and anticorrosive properties of the concrete can be fully utilized to obviously reduce the construction cost of the offshore wind generating set and improve the durability of the tower drum structure.

Therefore, by adopting the tower drum structure with the structure, the cost of the tower drum structure of an offshore wind power construction project can be obviously reduced while the robust support is provided, and the durability of the tower drum structure is improved by fully utilizing the waterproof and anti-corrosion characteristics of concrete, so that the requirement of continuously reducing the engineering construction cost of the tower drum structure of a high-power offshore wind power generator set is met, and the offshore wind power generator set is ensured to safely, reliably and stably operate.

Although a few embodiments of the present invention have been shown and described, it would be appreciated by those skilled in the art that changes may be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the claims and their equivalents.

Claims

1. The utility model provides a tower section of thick bamboo structure for offshore wind generating set, tower section of thick bamboo structure includes tower drum basis (10), concrete tower section of thick bamboo (20) and steel tower section of thick bamboo (30) that from the bottom up installed in proper order, its characterized in that, tower section of thick bamboo structure still includes:

a concrete transition section (40, 40-1, 40-2, 40-3), the concrete transition section (40, 40-1, 40-2, 40-3) being installed between the concrete tower tube section (20) and the tower base (10) and having a tube shape with a sectional area gradually increasing from top to bottom, wherein the concrete transition section (40, 40-1, 40-2, 40-3) has a curved generatrix with a non-constant curvature and the bottom sectional area of the concrete transition section (40, 40-1, 40-2, 40-3) is more than 2 times of the top sectional area;

a prestressed portion (50) distributed in a wall of the concrete transition section (40, 40-1, 40-2, 40-3) and a wall of the concrete drum section (20), the prestressed portion (50) including a first tendon (53) and a second tendon (54), an upper end of the first tendon (53) being anchored at a position of the steel drum section (30) connected to the concrete drum section (20), a lower end of the second tendon (54) being anchored on the drum foundation (10), and a lower end of the first tendon (53) and an upper end of the second tendon (54) both being anchored on an inner surface of the concrete transition section (40, 40-1, 40-2, 40-3), the first tendon (53) and the second tendon (54) being anchored at the concrete transition section (40), 40-1, 40-2, 40-3) cross each other in the height direction and are arranged at alternating intervals in the circumferential direction of the concrete transition sections (40, 40-1, 40-2, 40-3).

2. The tower structure of claim 1, wherein the curvature of the curved busbars increases gradually from top to bottom or increases gradually and then decreases gradually.

3. The tower construction of claim 1, wherein the concrete transition sections (40, 40-1, 40-2, 40-3) have a bottom cross-sectional area that is less than 6 times a top cross-sectional area.

4. The tower structure of claim 1, wherein the concrete transition section (40, 40-1, 40-2, 40-3) is circular in cross-section, the top diameter of the concrete transition section (40, 40-1, 40-2, 40-3) is in the range of 8m to 15m, the bottom diameter of the concrete transition section (40, 40-1, 40-2, 40-3) is in the range of 20m to 35m, and the height of the concrete transition section (40, 40-1, 40-2, 40-3) is in the range of 20m to 40 m.

5. The tower construction of claim 1, wherein the concrete transition sections (40, 40-1, 40-2, 40-3) are polygonal in cross-section.

6. The tower construction of claim 1, characterized in that the tower base (10) is circular in cross-section, the diameter of the tower base (10) being in the range of 30m to 45 m.

7. The tower construction of claim 1, characterized in that the height of the concrete tower segment (20) is 30-70% of the sum of the heights of the steel tower segment (30) and the concrete tower segment (20).

8. The tower construction of claim 1, wherein the wall thickness of the concrete transition section (40, 40-1, 40-2, 40-3) at the portion connected to the concrete tower section (20) is gradually thinner from top to bottom, wherein the concrete tower section (20) is a prefabricated concrete component.

9. The tower construction of claim 1, characterized in that the tower foundation (10) is a suction cylinder foundation or a gravity foundation.

10. An offshore wind park comprising a tower structure as claimed in any one of claims 1 to 9.

11. A method of installing an offshore wind energy plant according to claim 10, characterized in that it comprises:

pouring concrete transition sections (40, 40-1, 40-2, 40-3) on the tower foundation (10);

after the concrete strength of the concrete transition sections (40, 40-1, 40-2, 40-3) reaches the design strength, dragging the tower foundation (10) and the concrete transition sections (40, 40-1, 40-2, 40-3) into a mooring area;

hoisting a concrete tower drum section (20) to the concrete transition section (40, 40-1, 40-2, 40-3), and adjusting the water displacement of the tower drum foundation (10) to achieve balance;

hoisting a steel tower cylinder section (30) to the concrete tower cylinder section (20) while adjusting the displacement of the tower foundation (10) to achieve equilibrium.

12. The method of claim 11, further comprising: after the concrete strength of the concrete transition section (40, 40-1, 40-2, 40-3) reaches the design strength, installing a part of a prestressed part (50) in the concrete transition section (40, 40-1, 40-2, 40-3); after the concrete tower section (20) has been hoisted onto the concrete transition section (40, 40-1, 40-2, 40-3), another part of the prestressing section (50) is installed in the concrete tower section (20).

13. The method of claim 11, further comprising: installing and debugging other components of the offshore wind generating set in the region to be moored after the steel tower barrel section (30) is installed; and integrally dragging the offshore wind generating set to be out of the port to a machine position for sinking and installation.