Coupling assembly and method of driving a monopile

1. A coupling assembly for connecting a tower or a transition piece of a wind turbine to a monopile comprising:

a first coupling part configured to be connected to the monopile, the first coupling part having a first annular connection face and an inclined first insertion hole being configured to be inserted by a fastener, wherein the first annular connection face has a primary circle comprising an annular arrangement of inclined openings of inclined first insertion holes forming an insertion hole circle, and a secondary circle comprising an annular arrangement of inclined openings of first insertion holes forming another insertion hole circle, the primary circle and the secondary circle being at a different radius from an axis of the wind turbine; and

a second coupling part configured to be connected to the first coupling part, the second coupling part having a second annular connection face configured to abut the first annular connection face of the first coupling part, wherein the second coupling part further comprises an inclined second insertion hole being configured to be inserted by the fastener,

wherein the first annular connection face comprises a contact region and a load transfer region, the contact region being a region of the first annular connection face between the primary circle and the secondary circle and aligned with a shell of the monopile where a driving unit hits against the first coupling part to drive the monopile into the ground during an installation of the monopile, the load transfer region being a region of the first annular connection face where loads are transferred from the second coupling part to the first coupling part;

wherein the contact region is a different region of the first annular connection face from the load transfer region;

wherein:

the first coupling part and the second coupling part are separate, unequal pieces such that the first coupling part has a height, measured as a distance from a bottom surface of the first coupling part to a top surface of the first coupling part, that is different than a height of the second coupling part, measured as a distance from a bottom surface of the second coupling part to a top surface of the second coupling part, and the inclined first insertion hole extends a length within the first coupling part from the first annular connection face that is different than a length that the inclined second insertion hole extends into the second coupling part from the second annular connection face.

2. The coupling assembly according to claim 1 , wherein the first annular connection face has at least two load transfer regions, the contact region being positioned radially between both load transfer regions.

3. The coupling assembly according to claim 1 , wherein the contact region is aligned with a connection region where the first coupling part is connected to the monopile.

4. The coupling assembly according to claim 1 , wherein the contact region is not configured to support a load of the wind turbine.

5. The coupling assembly according to claim 1 , wherein the load transfer region is configured to support a load of the wind turbine.

6. The coupling assembly according to claim 1 , wherein the first annular connection face has an elevation at the contact region configured to be hit against by the driving unit.

7. The coupling assembly according to claim 1 , wherein the first annular connection face has an inclined surface to protect the first insertion hole from being damaged by the driving unit.

8. The coupling assembly according to claim 7 , wherein the inclined surface is positioned radially inwards from the contact region.

9. The coupling assembly according to claim 7 , wherein the inclined surface is a load transfer region configured to support the load of the wind turbine.

10. The coupling assembly according to claim 1 , wherein the second coupling part further comprises a recess aligned with the contact region.

11. The coupling assembly according to claim 1 , wherein there is a gap between the first coupling part and the second coupling part at the contact region when the second coupling part is connected to the first coupling part.

12. The coupling assembly according to claim 1 , wherein the second coupling part further comprises a chamber configured to protect the second insertion hole.

13. A tower end of a tower of a wind turbine connected to the second coupling part of the coupling assembly according to claim 1 .

14. A method of driving a monopile of a wind turbine into the ground, a top end of the monopile being connected to the first coupling part of the coupling assembly according to claim 1 , the method comprising:

positioning the driving unit on the contact region of the first coupling part; and

hitting the driving unit against the contact region of the first coupling part to drive the monopile into the ground.

15. A coupling assembly for connecting a tower or a transition piece of a wind turbine to a monopile comprising:

a first coupling part configured to be connected to the monopile, the first coupling part having a first annular connection face and an inclined first insertion hole being configured to be inserted by a fastener, wherein the first annular connection face has a primary circle comprising an annular arrangement of inclined openings of inclined first insertion holes forming an insertion hole circle, and a secondary circle comprising an annular arrangement of inclined openings of first insertion holes forming another insertion hole circle, the primary circle and the secondary circle being at a different radius from an axis of the wind turbine; and

a second coupling part configured to be connected to the first coupling part, the second coupling part having a second annular connection face configured to abut the first annular connection face of the first coupling part, wherein the second coupling part further comprises an inclined second insertion hole being configured to be inserted by the fastener,

wherein the first annular connection face comprises a contact region and a load transfer region, the contact region being a region of the first annular connection face between the primary circle and the secondary circle and aligned with a shell of the monopile where a driving unit hits against the first coupling part to drive the monopile into the ground during an installation of the monopile, the load transfer region being a region of the first annular connection face where loads are transferred from the second coupling part to the first coupling part;

wherein the contact region is a different region of the first annular connection face from the load transfer region;

wherein the second coupling part is divided into a plurality of pieces stacked on top of each other in a vertical direction.

16. The coupling assembly according to claim 15 , wherein the first annular connection face has at least two load transfer regions, the contact region being positioned radially between both load transfer regions.

17. The coupling assembly according to claim 15 , wherein the first annular connection face has an elevation at the contact region configured to be hit against by the driving unit.

18. A method of driving a monopile of a wind turbine into the ground, a top end of the monopile being connected to the first coupling part of the coupling assembly according to claim 15 , the method comprising:

positioning the driving unit on the contact region of the first coupling part; and

hitting the driving unit against the contact region of the first coupling part to drive the monopile into the ground.

19. A tower end of a tower of a wind turbine connected to the second coupling part of the coupling assembly according to claim 15 .