Arrangement of a switchgear of a wind turbine

Abstract

A wind turbine with a switchgear arrangement is described. The wind turbine includes a tower, a rotor supported at an upper end of the tower, a generator, a transformer for increasing the voltage output of the generator prior to supplying a collector grid, and switchgear arranged between the transformer and the collector grid. The switchgear includes a first switching device associated with the transformer, and a second switching device associated with one or more cables connecting the wind turbine to another wind turbine in the collector grid. The first switching device is connected to, but located remotely from, the second switching device.

Claims

1. A wind turbine comprising: a tower; a rotor supported at an upper end of the tower; a generator coupled to the rotor to convert mechanical energy of the rotor to electrical energy; a transformer for increasing the voltage output of the generator prior to supplying a collector grid; and a switchgear arranged between the transformer and the collector grid, wherein the switchgear comprises: a first switching device coupled with the transformer, and a second switching device coupled with: a first cable connecting the first switching device with the second switching device, and a second cable and a third cable connecting the second switching device to a first wind turbine in the collector grid and a substation associated with the collector grid.

2. The wind turbine of claim 1, wherein the first switching device comprises a circuit breaker panel.

3. The wind turbine of claim 1, wherein the second switching device comprises at least one cable disconnector panel for connecting and disconnecting the wind turbine to/from the collector grid.

4. The wind turbine of claim 1, wherein the first switching device is located inside the tower.

5. The wind turbine of claim 1, wherein the first switching device is located adjacent to the transformer.

6. The wind turbine of claim 1, wherein the second switching device is located inside a container.

7. The wind turbine of claim 6, wherein the container is substantially weatherproof.

8. The wind turbine of claim 6, wherein the container is located outside the tower.

9. The wind turbine of claim 6, wherein the container is located on a platform.

10. The wind turbine of claim 9, wherein the platform is part of a foundation on which the tower is supported.

11. The wind turbine of claim 10, wherein the foundation comprises a structural transition piece on which the tower is supported, and the container is located within the transition piece.

12. The wind turbine of claim 6, wherein a base of the container includes access points for connecting cables to the second switching device.

13. The wind turbine of claim 12, wherein the container is supported on one or more legs such that the base is spaced apart from a supporting surface.

14. The wind turbine of claim 1, wherein the wind turbine is located offshore.

15. A wind power plant comprising a plurality of wind turbines as claimed in claim 1.

16. The wind turbine of claim 1, wherein the second cable coupled with the second switching device is connected to the substation and the third cable coupled with the second switching is connected to the first wind turbine from the second switching device.

17. The wind turbine of claim 1, wherein the second switching device is coupled to a second wind turbine and the second wind turbine is coupled to the substation such that the second switching device is coupled to the substation via the second wind turbine.

18. A wind turbine switchgear for location between a main transformer of a wind turbine and another wind turbine in a collector grid, the switchgear comprising a first switching device to be associated with the main transformer, and a second switching device to be associated with one or more cables connecting the wind turbine to the other wind turbine in the collector grid, wherein the first switching device is connected to, but located remotely from, the second switching device.

19. A method of constructing an offshore wind power plant comprising: installing a plurality of offshore foundations in an array; providing a containerised switchgear on each of the respective foundations; and connecting the containerised switchgear on the respective foundations to the containerised switchgear on another foundation in the array via electric cables prior to erecting wind turbines on the respective foundations.

20. The method of claim 19, further comprising: erecting a wind turbine on a foundation; providing a switchgear component inside the wind turbine; and electrically connecting the switchgear component to the containerised switchgear on said foundation.

21. The method of claim 20, further comprising electrically connecting the switchgear component to a transformer and testing the equipment as a combined unit prior to installing the equipment inside the wind turbine.

22. The method of claim 20, further comprising pre-installing the switchgear component inside a tower section and lifting the tower section onto the foundation.

23. The method of claim 19, further comprising pre-installing the containerised switchgear inside a transition piece on which a wind turbine tower is to be supported and lifting the transition piece onto the foundation.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) In order that the present invention may be more readily understood, an example of the present invention will now be described, by way of non-limiting example only, with reference to the following figures, in which:

(2) FIG. 1 is a schematic view of an offshore wind turbine in accordance with a first embodiment of the present invention;

(3) FIG. 2 is a schematic view of an offshore wind turbine in accordance with a second embodiment of the present invention;

(4) FIG. 3 is a schematic view of containerised switchgear in accordance with the present invention;

(5) FIG. 4 is a schematic showing a plurality of offshore foundations for wind turbines in which containerised switchgear is located on the respective platforms and connected prior to erecting wind turbines on the platforms; and

(6) FIG. 5 shows the platforms of FIG. 4 once the wind turbines have been erected.

DETAILED DESCRIPTION

(7) Referring first to FIG. 1, an offshore wind turbine 10 in accordance with a first embodiment of the present invention comprises a tower 12 supporting a rotor 14 at its upper end 16. The rotor 14 comprises a plurality of rotor blades 18, which are mounted to a hub 20. The hub 20 is mounted to a nacelle 22, which houses a generator and other electrical equipment, represented schematically by the box 24 in FIG. 1.

(8) The wind turbine 10 is located on an offshore foundation 26, which includes a platform 28 that is supported on a plurality of pillars 30 that are piled into the seabed. A transition piece 32 is provided on the platform 28 and the tower 12 stands on top of the transition piece 32.

(9) An oil-filled main transformer 34 is located inside the base 36 of the tower 12 and is electrically connected to the equipment 24 inside the nacelle 22 via a set of cables 38, which extend vertically inside the tower 12. A first switchgear device 40, in this case a SF.sub.6-insulated circuit breaker panel, is also located in the base 36 of the tower 12 adjacent the transformer 34, and is connected to the transformer 34 via cables or a busbar 42. In practice, other electrical equipment such as a power converter and monitoring and control equipment would also be located inside the tower 12, however these are not shown in the figures for reasons of clarity.

(10) A second switchgear device 44 is housed in a weatherproof container 46, which is located on the platform outside the tower. The second switchgear device 44 comprises a pair of disconnector switches associated respectively with an incoming grid cable 48 and an outgoing grid cable 50. The grid cables 48, 50 connect the wind turbine 10 to a collector grid as described in further detail later, and the disconnector switches allow the wind turbine 10 to be disconnected from the collector grid, for example when service operations on the wind turbine 10 are undertaken, and/or in the event of faults.

(11) The disconnector switches are connected to the circuit breaker panel 40 inside the wind turbine tower 12 via an electric cable 52, referred to herein as the wind turbine cable. The container 46 is up to fifty meters away from the circuit breaker panel 40 in this example. Traditionally the circuit breaker and the disconnectors comprising the wind turbine switchgear are located in the same physical location, arranged side-by-side and connected via busbar connections. Normally such a combined switchgear unit is located inside the tower 12. Separating the switchgear 40, 44 in accordance with the present invention represents a significant departure from the prior art and allows parts of the switchgear to be located remotely from other parts, as shown in FIG. 1, which provides greater flexibility for locating the switchgear 40, 44.

(12) FIG. 2 shows a second embodiment of the present invention in which the containerised switchgear 44 is located within the transition piece 32 of the foundation 26. This provides a convenient location for the container 46, below the tower 12, and at least partially obscures the container 46 from view so as to detract less from the visual appearance of the wind turbine 10. The transition piece 32 in this example has open sides, but in other examples the transition piece 32 may define a substantially enclosed or partially enclosed interior, which would further obscure the container 46 from view. Locating the container within the transition piece also provides additional protection for the container 46 against the elements and provides shelter for service personnel during servicing of the containerised switchgear equipment 44.

(13) The container 46 in this example is preferably substantially cubic and has dimensions of approximately 222 m3, which it will be appreciated is substantially smaller than a standard ISO shipping container. The container 46 is designed to accommodate the disconnector switches with relatively little clearance between the disconnector switches and the container walls. This ensures that the container 46 is as compact as possible, which provides efficiencies in terms of transportation and minimises any perceived adverse visual impact on the wind turbine 10. The small size of the container 46 also allows it to fit conveniently within the transition piece 32 if required, as discussed above.

(14) To facilitate servicing, the compact container 46 has a side panel 54 that can be removed. The removable side panel 54 provides service access to the disconnector switches without having to build this service space into the internal volume of the container 46. Further features of the container 46 will now be discussed with reference to FIG. 3, which shows the container 46 with the side panel 54 removed.

(15) Referring to FIG. 3, the container 46 is designed to allow quick and easy connectivity of the grid cables 48, 50 to the wind turbine 10. Accordingly, end terminations in the form of plugs 56 are fitted to the ends of the wind turbine cable 52 and to the ends of the incoming and outgoing grid cables 48, 50. These plugs 56 are simply inserted into corresponding sockets 58 of the disconnector switches. A hatch 60, which is shown open in FIG. 3, is provided in the base 62 of the container 46 to provide access to the sockets 58. The cables 48, 50, 52 are routed beneath the platform 28 to the container 46 to avoid a trip hazard on the platform 28.

(16) The container 46 is supported on legs 64, which serve to raise the base 62 of the container 46 above the platform 28 so that the hatch 60 is readily accessible. The legs 64 are detachable from the container 46 to facilitate transportation of the container 46. Installing the containerised switchgear 44 is straightforward, and simply requires opening the hatch 60 and connecting the cables 48, 50, 52. In the event of a fault occurring in the second switchgear 44, the entire container 46 can be quickly disconnected and replaced with a similar container, which is easily reconnected in the same way. The faulty container 46 may then be repaired offsite.

(17) If service operations are to be performed onsite on the containerised switchgear 44, then one or more side panels of the container 46 may be removed to provide service access to the switchgear 44. As mentioned above, FIG. 3 shows the container 46 with a side panel removed. The container 46 also includes pressure relief flaps 66 in the sidewalls 68, which automatically open to relieve excess pressure in the container 46 if required.

(18) Locating the switchgear or part of the switchgear inside a container 46 as described above allows greater flexibility in terms of locating the switchgear, and ease of replacement of the switchgear, but it can also provide further advantages in the context of constructing a wind power plant, as will now be explainer with reference to FIGS. 4 and 5.

(19) Referring to FIG. 4, this shows an array of offshore foundations 26a, 26b, 26c, upon which wind turbines are to be built. In this example three foundations are shown, but there would normally be many more than this for a typical offshore wind farm. The foundations 26a, 26b, 26c are often constructed a year or more before the wind turbines are installed. The transition pieces 32 are also generally installed prior to construction of the wind turbines. As shown in FIG. 4, containerised switchgear 44a, 44b, 44c is arranged on each of the foundations 26a, 26b, 26c before the wind turbines are installed. This allows the incoming and outgoing grid cables 48a-c, 50a-c to be connected and tested prior to installing the wind turbines. The grid cables 48a-c, 50a-c are connected to a substation 68, which includes a step-up transformer 70 for increasing the voltage before supplying a distribution grid (not shown). The substation includes its own switchgear 72, which allows the substation to be connected to or disconnected from the collector grid as required. It will be appreciated that the containerised switchgear 44a, 44b, 44c provides an advantage over prior art arrangements (in which the entire switchgear is located inside the wind turbine) because it allows the collector grid cabling to be installed and tested prior to installing the wind turbines.

(20) Referring to FIG. 5, this shows wind turbines 10a-c installed on the respective offshore foundations 26a-c to form a collector grid 74. The wind turbines 10a-c each include a circuit breaker panel 40a-c inside the tower 12a-c, which is electrically connected to a respective containerised switchgear component 44-a-c on its foundation 26a-c via a wind turbine cable 52a-c in the same way as discussed above in relation to FIGS. 1 to 3.

(21) Separating the switchgear 40, 44 in the way described above also allows the circuit breaker 40 and the transformer 34 to be tested together as a combined unit offsite before being transported to the wind turbine site.

(22) It will be appreciated that many modifications or variations may be made to the embodiments described above without departing from the scope of the present invention as defined by the following claims. For example, whilst the containerised switchgear in the above examples comprises a pair of disconnector switches, in other examples the containerised switchgear may have only a single disconnector switch associated with either the incoming or the outgoing grid cable.