Floating wind turbine comprising an integrated electrical substation

Abstract

The invention relates to a wind turbine having an integrated electrical substation, and to a floating offshore wind farm which are optimized in terms of capital costs, economic efficiency, and installation space requirements.

Claims

1. A wind turbine comprising at least one rotor and a floating foundation, wherein the floating foundation comprising at least one floating hollow body, wherein the floating foundation comprising an electrical substation installed in the hollow body of the floating foundation, wherein the electrical substation installed in the hollow body at least comprises a transformer having an input side, wherein the floating foundation comprising a plurality of controllable power switches coupled to an input side of a main switch, wherein the plurality of controllable power switches are adapted and configured to connect a high voltage from a cable that connects two or more wind turbines in a strand with the input side of the main switch and to disconnect the high voltage from the cable from the input side of the main switch, and the main switch is provided between the transformer and the plurality of controllable power switches, the main switch is adapted to connect or disconnect the input side of the transformer to or from the plurality of controllable_power switches.

2. The wind turbine according to claim 1, wherein the electrical substation are installed in the regions of the hollow body or bodies that are below the surface of the water.

3. The wind turbine according to claim 1, wherein the regions of the hollow body that are below the surface of the water during operation are designed as a cooling surface, and in that the cooling surfaces are used to cool a transformer and/or a reactive current compensation coil.

4. The wind turbine according to claim 1, wherein parts of the hollow body are designed to encapsulate part of a high-voltage electrical assemblies of the electrical substation.

5. The wind turbine according to claim 1, wherein the hollow body is made of metal and shield electrical components of the electrical substation.

6. The wind turbine according to claim 1, wherein the floating foundation comprises one or more hollow bodies, the transformer and the power switch for strands arranged in the hollow body receiving the electrical substation being a first hollow body and a reactive current compensation coil and a high-voltage switch panel arranged in a second hollow body, in that the first hollow body and the second hollow body are connected to one another by one or more struts, and in that cables which electrically connect the transformer and the high-voltage switch panel are laid in at least one of the struts.

7. The wind turbine according to claim 1, wherein the hollow body receiving the electrical substation and/or the hollow body receiving a reactive current compensation coil have closable openings, and in that these openings are above the surface of the water.

8. The wind turbine according to claim 7, wherein a closable opening is at least one meter above the surface of the water.

9. The wind turbine according to claim 1, wherein each rotor is mounted in a nacelle that is arranged on a tower.

10. The wind turbine according to claim 1, wherein an axis of rotation of the rotor or rotors extends horizontally or vertically.

11. The wind turbine according to claim 1, wherein the rotor has one wing, two wings or three wings, a Darrieus rotor or a Savonius rotor, or is a wind energy kite.

12. A floating offshore wind farm, consisting of at least two wind turbines which are connected via electrical lines/cables to at least one electrical substation located offshore, wherein one of the wind turbines is a wind turbine comprising at least one rotor and a floating foundation, the floating foundation comprising at least one floating hollow body, wherein the floating foundation comprising an integrated electrical substation installed in the hollow body, wherein the electrical substation, the electrical substation installed in the hollow body at least comprise a transformer having an input side, wherein the floating foundation comprising a plurality of controllable power switches coupled to the input side a main switch, wherein the plurality of controllable power switches are configured to connect a high voltage from a cable that connects two or more wind turbines in a strand with the input side of the transformer and to disconnect the a high voltage from the cable from the input side of the transformer, and wherein the wind turbines are joined to the electrical substation of the wind turbine comprising an integrated electrical substation.

13. The floating offshore wind farm according to claim 12, wherein fewer than five wind turbines-are interconnected to form the strand.

14. The floating offshore wind farm according to claim 12, wherein only so many wind turbines are joined to the electrical substation such that all of the energy can be transmitted to mainland via just one high-voltage export cable.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) In the drawings:

(2) FIG. 1 shows the topology of a floating offshore wind farm according to the invention,

(3) FIG. 2 shows a wind turbine having a Spar Buoy floating foundation,

(4) FIG. 3 shows a wind turbine having a semi-submersible floating foundation,

(5) FIG. 4 shows a cross section through a wind turbine according to the invention comprising an integrated electrical substation in a side view,

(6) FIG. 5 shows the embodiment according to FIG. 4 in a view from above, and

(7) FIG. 6 shows the details of the electrical circuit of the embodiment according to FIGS. 4 and 5.

DESCRIPTION OF THE EMBODIMENTS

(8) A floating offshore wind farm 1 according to the invention is shown schematically and in a greatly simplified manner in FIG. 1. This wind farm 1 comprises a large number of wind turbines W.

(9) The wind turbine S comprising an integrated electrical substation 14 differs from the other wind turbines W in that an electrical substation 14 is integrated into the foundation of the wind turbine S. The details of this integration are explained in more detail below with reference to FIG. 2 to 5. In the context of the invention, it should be noted that in each case three wind turbines W are combined to form a strand 3. Each strand 3 ends in the wind turbine comprising an integrated electrical substation S. The electrical interconnection of the individual strands or the wind turbines W on a strand is explained in more detail below.

(10) The number of wind turbines W on a strand 3 is less than 5; in the example shown, it is equal to 3. All strands 3 lead into the wind turbine S comprising an integrated electrical substation and are switched on and off separately there. Details regarding this can be found in FIG. 3 and are explained in more detail in connection with FIG. 6.

(11) The electrical energy generated by these wind turbines W is transported to the electrical substation 14 of the wind turbine S comprising an integrated electrical substation via a cable 5 which connects the wind turbines W of a strand 3 to one another. By way of example, the wind turbines of a strand 3 are referred to as W1, W2 and W3 in FIG. 1.

(12) The electrical energy generated by the wind turbines W1, W2 and W3 is transported to the electrical substation 14 inside the wind turbine S via a common cable 5. Therefore, they can only be put into operation or taken out of operation together. If, for whatever reason, the power switch 19, which is associated with a strand and is in front of the electrical substation 14 of the wind turbine S, is open, then all three wind turbines W1, W2 and W3 of the affected strand 3 no longer supply any electrical energy to the electrical substation 14 in the wind turbine S.

(13) This supposed disadvantage actually leads to a considerable economic advantage because the number of power switches can be drastically reduced. Only one power switch 19 has to be provided in the electrical substation 14 per strand 3 and not, as in conventional wind farms, one power switch per strand 3 and a multi-panel switchgear per wind turbine W. This results in considerable cost advantages. Because no power switches have to be accommodated in the foundations or the towers of the wind turbines W, the probability of failure of the wind turbines is reduced.

(14) The number of wind turbines on a strand 3 is less than 5. As a result, the line cross section of the cables 5 of a strand 3 can still be relatively small, and light, inexpensive, yet powerful aluminum cables can be used.

(15) Since the wind turbines W generally do not fail unexpectedly but are only serviced in the sense of preventive maintenance, it is easily possible to shut down all wind turbines W of a strand 3 at the same time and to carry out maintenance on all turbines of a strand at the same time. The downtimes caused by maintenance therefore remain the same, although only one power switch is used per line.

(16) In FIGS. 2 and 3, two different types of wind turbines W having a floating foundation are shown in a greatly simplified manner. The wind turbine W comprises a tower 7 and a nacelle 9. The generator driven by the rotor 11 is arranged in the nacelle 9. At the foot of the tower 7, said tower is connected to a floating foundation 13.

(17) FIG. 2 shows a Spar Buoy floating foundation. This type of floating foundation 13 comprises an elongate hollow body 15. The region of the hollow body 15 that is located below the surface of the water is referred to as 15.1. A small part 15.2 of the hollow body 15 is located above the surface of the water.

(18) In FIG. 3, a second embodiment of a wind turbine having a floating foundation 13 is shown as an example of all semi-submersibles. In this embodiment, three hollow bodies 15a, 15b and 15c are connected to form a triangle using tubular struts 17. The wind turbine comprising the tower 7, nacelle 9 and rotor 11 is installed on one of the hollow bodies, specifically the hollow body 15b. The hollow bodies 15a, 15b and 15c do not have to have the same dimensions and geometries.

(19) All hollow bodies 15, 15a, 15b and 15c have a very large volume, since they not only bear the weight of the wind turbine W, but also because they accommodate considerable amounts of ballast water in order to stabilize the wind turbine W.

(20) FIG. 4 shows the two hollow bodies 15a and 15c from FIG. 3 in section and in a greatly simplified manner. In the hollow body 15c, various power switches 19 are shown in simplified form as a block. As already mentioned in connection with FIG. 1, there is a power switch for each strand 3, by means of which the electrical connection between a strand 3 and the downstream transformer 21 can be interrupted or created.

(21) The cables 5 of the strands 3 and an electrical connection line between the power switches 19 and the transformer 21 are not shown in FIG. 4 since they are only a schematic illustration of the inventive concept.

(22) A closable assembly opening 23 is provided on the top of the hollow body 15c. The assembly opening 23 is dimensioned such that the largest component (that is usually the transformer 21 and the reactive current compensation coil 25) of the electrical substation 14 can be lifted through the assembly opening 23 into the hollow body 15c. In the event of repair or replacement, all components of the electrical substation 14 can be inserted through the assembly opening 23 into the hollow body 15c and lifted out again if necessary.

(23) A strut 17 is shown as an example between the hollow body 15c and the hollow body 15a. This strut 17 is designed as a tube so that it can simultaneously be used as a cable conduit for the cables 27 which connect the transformer 21 to the high-voltage switch panel 29.

(24) The reactive current compensator 25 is connected to the high-voltage export cable via a high-voltage switch panel 29.

(25) The electrical energy generated in the wind farm 1 is transmitted to the mainland via this high-voltage cable at a voltage of, for example, 230 kV.

(26) The amount of ballast water 31 in the hollow bodies 15 is dimensioned such that the floating foundation 13 has sufficient depth and sufficient inertia to ensure a stable position of the wind turbine W which is mounted on the floating foundation 13. The integration according to the invention of an electrical substation 14 in one or more hollow bodies 15 of the floating foundation 13 increases the mass within the hollow bodies 15 and the amount of ballast water 31 can be reduced accordingly.

(27) It is also possible to completely omit ballast water from the hollow body 15c, 15b in which the electrical substation 14 is located.

(28) In contrast to what is shown in the simplified illustration in FIG. 4, the internal components according to the invention, such as the power switch 19, transformer 21 and reactive current compensator 25, can also be installed in hollow bodies 15 below the waterline. This results in a lower position of the center of gravity and consequently a greater metacentric height, which increases the floating stability of the foundation 13.

(29) The lower regions 15.1 of the hollow body 15, which are immersed in the sea water, are cooled by the sea water such that the waste heat generated in the electrical substation 14 can partly be dissipated directly into the sea water via the outer walls of the hollow body 15. The hollow body 15 can also be designed in such a way that it simultaneously encapsulates the electrical substation or the transformer 21 and/or the reactive current compensation coil 25. A direct heat exchange between the transformer oil of the transformers 21, the reactive power compensation coil 25 and the seawater is then made possible, so to speak, without an additional component. The construction costs are reduced, and very effective heat dissipation is guaranteed.

(30) In FIG. 5, the view of the embodiment according to FIG. 3 is shown again from above. From this, the distribution of the various components, specifically the wind turbine W and electrical substation 14 comprising the transformer 21, power switches 19, reactive current compensator 25 and high-voltage switch panel 29, to the three hollow bodies 15a, 15b and 15c can be clearly seen.

(31) It is clear from this illustration that the strands 3.1 to 3.n are guided to the wind turbine S comprising an integrated electrical substation 14. A high-voltage line 33 is shown at the output of the reactive current compensation coil 25. The electrical energy generated in the wind farm 1 is transported to the mainland via said line.

(32) The electrical components in the hollow bodies 15c and 15b and their electrical connection are shown in somewhat greater detail in FIG. 6. In the hollow body 15c, a total of seven strands 3.1 to 3.7, each comprising three wind turbines W, are connected to the switch system 19. In addition, a main switch 20 is also provided that can connect or disconnect the input side of the transformer 21 to or from the switch panel 19 of the strands 3.1 to 3.7.

(33) The electrical substation 14 comprises a transformer which transforms the electrical energy generated by the wind energy plants to 230 kV. This alternating current is conducted to the high-voltage switch panel 29 via the cable 27. The control panel 29 is used to connect and disconnect the high-voltage export cable and at the same time to connect the reactive current compensation coil 25 to the export cable 33.