Connection structure for a marine installation, marine installation and method of erecting a marine installation

Abstract

A connection structure for connecting a seabed anchor to a superstructure for electrical power engineering has a horizontally encircling, vertically extending wall, which bounds a spatial region inside the connection structure. A first connecting section is configured for connection to the superstructure. A second connecting section is configured for connection to the seabed anchor.

Claims

1. A marine installation, comprising: a superstructure for power engineering, said superstructure containing a high voltage direct current substation having an alternating current to direct current converter module in order to enable DC power transmission of AC power to an onshore station; a foundation having a number of connection structures for connecting a seabed anchor to said superstructure, each connection structure including: a vertical, horizontally encircling wall bounding a spatial region; a first connecting section configured for connection to said superstructure; and a second connecting section configured for connection to the seabed anchor, said second connecting section having a shape transition of a cross-sectional shape of said encircling wall to a cross-sectional shape of an upper end of the seabed anchor, said shape transition proceeding from substantially rectangular to circular; and at least one self-priming pump within the spatial region in order to supply and/or to discharge seawater as a coolant to and/or from the superstructure; a number of seabed anchors and the number of connection structures being equal and being one or more; wherein each of said seabed anchors is connected to a respective said connection structure by way of said second connecting section; wherein said at least one connection structure is connected to said superstructure by way of said first connecting section; a sea cooling facility with supply pipes and/or discharge pipes, which are arranged at least partially within the seabed anchor and/or within the spatial region of said connection structure.

2. The marine installation according to claim 1, wherein a shape of said encircling wall is substantially rectangular or square, and said encircling wall is formed with planar sections and rounded corners between said planar sections.

3. The marine installation according to claim 1, wherein said first connecting section has a circumferentially completely encircling flange on said encircling wall, said flange being formed with through holes for screws for connection to the superstructure.

4. The marine installation according to claim 1, wherein said connection structures have a base connected to said encircling wall and at least partially closing off said spatial region toward the bottom.

5. The marine installation according to claim 1, wherein said connection structures have at least one cable connector and/or cable plug within said spatial region for electrically connecting an underwater cable to a cable of the superstructure.

6. The marine installation according to claim 1, wherein said connection structures have: a horizontal surface area attached to said encircling wall outside said spatial region; and a reversibly closable opening formed in said encircling wall in order to allow access from said spatial region to said horizontal surface area.

7. The marine installation according to claim 1, wherein said number of said connection structures and said number of said seabed anchors is four.

8. The marine installation according to claim 1, wherein said connection structure is disposed substantially below a 100-year wave level and above a lowest tidal range level.

9. The marine installation according to claim 1, wherein each said seabed anchor comprises: a hollow driven pile to be driven or driven into a seabed below said superstructure and said pile having a smaller cross-sectional size than the spatial region of the connection structure; and/or a suction bucket to be anchored or anchored to the seabed by way of a pressure difference and said suction bucket having a larger cross-sectional size than the spatial region of the connection structure.

10. The marine installation according to claim 1, wherein said superstructure has at least one supporting wall arranged vertically substantially in line with a section of said vertical wall of said connection structure.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

(1) FIG. 1 is a schematic plan view onto a connection structure according to the invention;

(2) FIG. 2 is a top perspective view thereof;

(3) FIG. 3 is a similar perspective view showing specific cable runs and the connection to a seabed anchor;

(4) FIG. 4 is a perspective, partly broken-away detail of the connection structure and a cable connection to the seabed anchor;

(5) FIG. 5 is a perspective view of the connection structure and the seabed anchor;

(6) FIG. 6 is a schematic side view showing the connection between a seabed anchor and a lower part of the connection structure, as well as a highly schematic view of a suction bucket;

(7) FIG. 7 is a perspective view of a marine installation supported by four foundation piles;

(8) FIG. 8 is a partial side view of the marine installation; and

(9) FIG. 9 is a side-by-side comparison of a marine installation according to the invention and a marine installation according to the prior art.

(10) The invention is not restricted to the illustrated or described embodiments.

DETAILED DESCRIPTION OF THE INVENTION

(11) Referring now to the figures of the drawing in detail and first, particularly, to FIG. 1 thereof, there is shown schematically illustrates, in a plan view along a vertical direction 103, a connection structure 100 according to one embodiment of the present invention. The connection structure is designed to connect a seabed anchor (also referred to as: seabed anchoring means, seabed anchoring device, or tower) to a superstructure for electric power engineering. The connection structure 100, which is illustrated in a schematic perspective illustration in FIG. 2, in a schematic perspective transparent representation in FIG. 3 and in a perspective, partially broken away view in FIG. 4, comprises a horizontally encircling metallic wall 101 extending in the vertical direction 103, which wall bounds a spatial region 105. Furthermore, the connection structure 100 has a first, upper connecting section 107, which is designed for connection to a superstructure for power technology. Furthermore, the connection structure 100 has a second, lower connecting section 109, which is designed for connection to a seabed anchor, which is partially shown in FIG. 4 and designated by reference numeral 111.

(12) As can be seen from the plan view of FIG. 1, the shape of the encircling wall 101 is substantially square with planar sections 113 and with rounded edges or rounded corners 115. The first connecting region 107 has a circumferentially completely encircling flange 117, which is formed with through holes 119, through which screws can be led for connection to a superstructure. Therefore, the area formed by the flange 117 forms a plane defining the position of a lower section of a superstructure.

(13) The connection structure 100 furthermore has a base 121, which is connected to the wall 101, and closes the spatial region 105 to (vertically) below, at least partially. The base has a central opening 123, through which, for example, an underwater cable can be pulled into the spatial region 105 from below the connection structure 100. Within the spatial region 105, a plurality of cable connectors and/or cable plugs 125 are arranged and mounted (for example on the wall 101) in order to electrically connect an underwater cable 127 to a cable 129 of the superstructure. In the illustrated embodiment, the underwater cables 127 are led through separate cable openings 131 in the base 121. The underwater cables 127 may also be led through further cable openings 132 in an upper region of the seabed anchor 111 into an interior 133 of the seabed anchor 111, as can be seen, in particular, in FIGS. 3 and 4.

(14) In the illustrated embodiment of FIGS. 1 to 4, a centrifugal pump 135 is also arranged within the spatial region 105 in order to supply and/or discharge seawater as a coolant to and/or from the superstructure. For this purpose, feeds and discharges for the coolant within the spatial region are partially provided, which are not illustrated in FIGS. 1 to 4 for the purpose of simplification.

(15) The connection structure further comprises a horizontal surface area 137 attached to the wall 101 and arranged outside the spatial region 105, and an, in particular, reversibly closable opening 139 in the wall 101 in order to allow access from the spatial region to the horizontal surface area 137. A railing 141 bounds the area 137 where it is not bounded by the wall 101. The opening 139 can be reversibly closed by a door (not illustrated). Additional equipment, such as a rope winch, can be arranged on the area 137 in order to pull up an underwater cable from below.

(16) At least two of the connection structures illustrated in FIGS. 1 to 4 may be connected to form a connection structure arrangement according to one embodiment of the present invention such that respective flanges 117 of the respective connection structures lie substantially in a horizontal plane. This horizontal plane will be brought to a desired predetermined height above sea level and define an underside of the superstructure to be placed onto the connection structure.

(17) FIG. 5 illustrates a foundation for a superstructure for electrical power engineering according to one embodiment of the present invention. The foundation 150, which is illustrated in a perspective view in FIG. 5, comprises a connection structure 100 according to one embodiment of the present invention (as illustrated, for example, in FIGS. 1 to 4) and a seabed anchor 111, which is anchored in a seabed 153. The seabed anchor 111 is formed in the embodiment illustrated in FIG. 5 as a hollow driven pile, which is driven into the seabed 153 and has a circular cross-sectional shape whose diameter d is smaller than a side length l of the cross section of the spatial region 105 or of the encircling wall 101.

(18) The seabed anchor 111 is connected at an upper end to the lower connecting section 109 of the connection structure 100, for example by grouting, welding, screwing, etc. The connection structure 100 has a shape transition 155 (see FIG. 6) of a cross-sectional shape of the spatial region 105 or of the wall 101 to a cross-sectional shape of an upper end of the seabed anchor 111. The shape transition 155 in this case proceeds essentially from square to circular, as can be seen in FIGS. 5 and 6.

(19) FIG. 6 further illustrates, in a highly schematic view, a suction bucket 111. The suction bucket has a cross-sectional area that is larger than the cross-sectional area of the connection structure 100. Typically, the bucket will have a diameter such that its cross-sectional area is 2-10 times greater than that of the connection structure 100. There is also provided an evacuation valve V for aspirating water out of the suction bucket 111 during its installation in the seabed.

(20) FIG. 5 illustrates, in a schematic perspective view, a foundation 150 according to one embodiment of the present invention, said foundation having a single connection structure 100 according to one embodiment of the present invention, as well as a single seabed anchor 111, here in the form of a pile or piling 111. According to other embodiments, a foundation comprises four seabed anchors, each with associated connection structures 100.

(21) FIG. 7 illustrates, in a schematic perspective view, a marine installation 160 according to one embodiment of the present invention. The marine installation has a superstructure 157 for power engineering and a foundation 250, which is formed, for example, by four foundations 150, as illustrated in FIG. 5. Therefore, the superstructure 157 is mounted on the flanges 117 (see FIG. 2) of the respective connection structures 100.

(22) FIG. 8 illustrates a schematic side view or side sectional view of the installation 160, which is illustrated in FIG. 7 in a perspective view. The superstructure 157 in this case comprises a supporting wall 163 (or 164), which is arranged vertically (that is to say in the vertical direction 103) substantially in line with a section 165 (or 166) of the vertical wall 101 of the connection structure 100. This achieves an improved support of the superstructure 157. A cable deck level 180 is below a lowest level 182 of the superstructure 157.

(23) FIG. 9 shows a schematic side view of a marine installation 160 as compared to a conventional marine installation 170. Line 161 illustrates a lowest tidal range level and line 159 illustrates a 100-year wave level. As can be seen in FIG. 9, the connection structure 100 is located substantially below the 100-year wave level 159, but substantially above the lowest tidal range level 161.

(24) The conventional marine installation in the conventional superstructure 167 comprises a bottom deck 169, which is used to connect and pull up cables.

(25) Pulling up and connecting cables is performed according to one embodiment of the present invention within the spatial region of the connection structure 100, thus being able to save the connection deck 169 of the superstructure, whereby a total height h1 of the marine installation 160 according to one embodiment of the present invention can be achieved, which total height h1 is lower (for example by 3 to 6 m) than a total height h2 of the conventional marine installation 170. The heights h1, h2 are each measured here with respect to the lowest tidal range level 161.

(26) The foundation, such as illustrated in FIG. 5 or illustrated in FIG. 7 below the superstructure, may be used for various component parts of an offshore wind farm. According to embodiments of the present invention, an underwater cable or cable of the superstructure in the conical part (see, for example, the transition region 155 in FIG. 6) of the connection structure 100 is led along the walls, in order to ensure sufficient space for the connection within the spatial region of the connection structure 100. This optimization can lead to a reduction in the weight and the volume of the superstructure, since the cable deck (for example deck 169 of the conventional superstructure 167 in FIG. 9) can be omitted. Another positive aspect is that the cable tension is located within the spatial region of the connection structure so as to always be independent of the weather, without the need for a temporary housing, which in turn can save time and money.

(27) Three of the foundation piles illustrated in FIG. 7 can serve here as a cable guide for up to 16 AC cables (33 kV, 66 kV) and two DC cables. The fourth foundation pile may be specifically embodied to receive the cooling water pumps of an HVDC system. For example, an open sea cooling water system can be implemented. The use of self-priming centrifugal pumps (for example pump 135, illustrated in FIG. 2) above the water line within the spatial region of the connection structure instead of submersible pumps previously used for the HVDC platform may improve accessibility, and thus may simplify maintenance and reduce possible repairs. Conventionally, the submersible pumps had to be pulled out of the water and, in the process, divided into several sections in a time-consuming manner in order to access the actual pump head at the inlet of the rising pipe.

(28) The connection structure 100 may also be considered as an expansion of the cylindrical structure to a square structure. This expansion can bring several advantages: on the one hand, the flow of force and the introduction of force from the superstructure into the connection structure can be optimized. This can lead to reduced deflection and to a saving of material in the region of the double base of the superstructure. On the other hand, cable tension and cable connections can be performed in a closed space (the spatial region 105) and are thus independent of external weather conditions.

(29) An additional cable deck for the superstructure may thus be superfluous. This can save volume inside or below the superstructure. In addition, the spatial region may be used as a cable connecting space and may be in the range of the influence zone of a one-hundred-year wave. This can lead to a possible reduction in the height of the structure. The dimensions of the expansion of the connection structure and the upper flange may, despite installation tolerances, make an optimum flow of power into the transverse and longitudinal walls of the double base of the superstructure possible. The dimensions of the connection structure can be chosen so that the (supporting) walls of the superstructure represent an extension of the main walls or of the supporting walls of the superstructure. In order to prevent thermal influencing by a welded connection and to avoid the resulting necessary offshore coating work after installation of the superstructure, in a preferred embodiment, the connection between the connection structure and the superstructure should be designed as a screw connection by means of an inner or outer flange. Alternatively, a positively locking connection by means of grouting or the equivalent can be performed.

(30) The combination of four foundation piles (as illustrated, for example, in FIG. 7) can be used as a foundation for a superstructure of approximately 10,000 tons. In this case, up to approximately 16 AC cables plus two DC cables can be led inside three of the four foundation piles. The fourth foundation pile can provide sufficient space for housing the pipes and pumps for the cooling water circuit. The upper part of the connection structures can in this case preferably be designed so that it serves to position directly adjacent connection structures on the foundation piles prior to the grouting process.

(31) According to embodiments of the present invention, the cable coming from the clusters of the wind farm can be pulled vertically up to below the ceiling of the transition structure within the foundation piles by means of deflection rollers. The tensile force can be exerted here on the cable by means of deflection rollers by means of a temporarily erected rope winch lying outside the interior. If the cable is fully raised, the cable hang-off can be produced directly below the connection structure, in the parallel part of the foundation pile, on a hang-off deck. In this case, the outer sheathing of the cables is removed and the steel reinforcement contained is fixed by means of a flange in order to produce a strain relief of the underwater cables. In order to be able to pull the cable as described, a circular opening (for example 123 shown in FIG. 1) is provided in the deck of the connection structure. If the cable hang-off has been completed, the cables are lowered again, led on the hang-off deck in the outer diameter of the deck, and the complete outer insulation is removed. From there, the individual cores of the cables are led along the conical wall of the connection structure and led vertically through openings of the cable deck in the transition or connection structure. There, the cables can be connected to the platform internal systems and be led further through the platform.

(32) Pipes and pumps of a cooling water circuit can be installed within a foundation pile. If installed above the lowest tidal range level, the suction pumps used previously could be replaced here by centrifugal pumps. The pumps arranged above the water level can therefore be easily maintained by access to the spatial region.

(33) Due to the cable routing within a foundation pile, it is possible, according to the prior art except for the two export cables, to dispense with a steel cable guide in the form of a J-tube and to use a flexible cable lead-through together with flexible cable protection.

(34) In one embodiment, instead of a driven pile 111, a foundation structure with one or more, for example three, suction buckets 111 may also be used (cf. FIG. 6). In that case, other advantages may be produced, such as, for example, prevention of the pile driving process during installation, no underwater grouting operation offshore, reduction of crane ship lifting capacity compared to a jacket installation or even abandonment of crane ship operations for the foundation installation, offshore by self-floating transport. Another advantage of this design is that the entire system can be fitted with all attachments without the component parts being exposed to the high acceleration forces and fatigue during the pile driving process. In this case, the connection structure can be extended downward according to the water depth and the installation site and be disassembled at the bottom end with the suction buckets (suction cans) as a complete unit as a foundation structure.