ELECTRICAL SUBSTATION, SYSTEM AND CONSTRUCTION PROCESS

Description

FIELD OF THE INVENTION

[0001] The present invention relates in particular to a wind farm electrical substation which is configured to raise or lower the voltage of the electricity produced by wind turbines and to allow its transmission with minimal loss to an electrical distribution network (known by the English acronym "GRID"). The invention is advantageously applied to the production of energy on land (i.e. "onshore") or at sea (i.e. "offshore").

[0002] The area of ​​"offshore" applications will be detailed in more detail below. TECHNOLOGICAL BACKGROUND OF THE INVENTION

[0003] An offshore wind farm consists of a variable number of wind turbines. Their unit power is also variable. We often talk about the total power of the wind farm, which is expressed in megawatts (MW) and commonly ranges from 200 MW to 900 MW.

[0004] To be transported with optimal efficiency (reducing losses between departure and arrival), it is necessary to increase the electrical voltage (33kV / 220kV for example). A transformer station or electrical substation (in English "OSS" for "Offshore Sub-Station") is therefore necessary. It is mainly made up of at least one transformer and all the equipment necessary for its proper operation, maintenance, control, safety, connection to the network and access on board.

[0005] The current period known as the "energy transition" is essentially characterized by the fact that we are tending to produce more and more electricity from renewable sources (wind, current, tide, sun, etc.), replacing fossil and / or polluting sources (oil, coal, nuclear).

[0006] This energy transition will only be possible if robust industrial solutions are offered on the market and allow us to be competitive with current energy sources. Thus, we compare the cost of energy sources using the LCOE (Levelized Cost of Energy), in € / kWh.

[0007] The market therefore expects a significant drop in the cost of energy from offshore wind power.

[0008] A substation generally comprises a structure, generally of the "mechanically welded" type, electrical equipment (shielded panels known by the acronym "GIS", transformers, etc.), lifting equipment, fire-fighting equipment, energy production for its own additional needs (operation of a crane, etc.) and secondary structural elements (stairs, ladders, etc.).

[0009] The offshore wind sector is mainly characterized by: > the use of very powerful turbines (power > 5MW) generating increasingly high power; > a very large number of wind turbines (> 50 wind turbines); > significant resources for transport and installation at sea; > very severe environmental conditions (ground, swell, current, wind, etc.); > more stringent regulatory requirements than in the land domain (fatigue resistance, safety, etc.); > very demanding operating conditions (difficulty of maintenance, access, handling, etc.).

[0010] Current substation construction practice involves designing electrical substations specific to each customer and each site to be equipped. Thus, each substation has its own characteristics in terms of architecture, power, mass, and dimensions. Each newly built substation is therefore, in a way, a "prototype."

[0011] To design such assemblies and while seeking to reduce costs, those skilled in the art can rely on document GB 253 217.

[0012] This document proposes to achieve savings by "integrating" the substation into a wind turbine foundation, thereby eliminating the additional foundation on which the substation rests. However, this solution has limitations, particularly in terms of mass. It is indeed difficult to add additional equipment that generates additional forces to a foundation already subjected to significant forces from the wind turbine. To reduce these forces, the skilled person will inevitably have to limit the electrical equipment or significantly reinforce the wind turbine foundation.

[0013] This necessarily limits the use cases of such a solution and at best would significantly increase the number of equipment that will have to be added to the wind turbine foundations. The interest of this solution for the skilled person can then be questioned.

[0014] The state of the art in this field can also be illustrated by: WO 2011 / 120591, WO 2012 / 144884, CN 204 126 320, CN 104 631 410, CN 203 942 186, CN 204 456 043, "THE TW 2.0 OFFSHORE TECHNICAL DESCRIPTION", SUSTAIN. THE WORDL SUSTAINABLE ENERGY FAIR (1999-05-15) and EP 2811160.

[0015] The present invention aims to provide a solution to this problem by rationalizing the construction of electrical substations and reducing their overall cost, without this having the slightest impact in terms of the equipment that such a substation usually contains, as well as in terms of safety and maintenance parameters in particular. SUMMARY OF THE INVENTION

[0016] Thus, the present invention relates mainly to a wind farm electrical substation, which is configured to raise or lower the voltage of the electricity produced by wind turbines of said wind farm in order to ensure its transport to an electrical distribution network, characterized in that it comprises n modules, n being an integer at least equal to 2, these modules, which each comprise an arrangement of several parts, having an identical shape and external dimensions, each module containing at least one electrical transformer configured to raise or lower said voltage, these modules being connected to each other so as to be able to supply said network with an overall electrical power equal to the sum of the powers of each transformer.

[0017] The basic technical idea is to propose an electrical substation composed of n standardized unit modules.

[0018] Each standardized unit module is designed to withstand the various stresses it will encounter during its life phases (on site in operation, during transport, during installation, taking into account the most unfavorable situations, thus allowing its prior certification).

[0019] Advantageously, the module accommodates all types of associated equipment and auxiliaries and is designed to be manufactured using a mass production process.

[0020] The result is a substation that fully meets current and future customer requirements.

[0021] According to other advantageous and non-limiting characteristics of this substation: said arrangement is the same from one module to another; the arrangements of a first and a second module are reversed, so that when they are positioned next to each other, all or part of their respective parts are symmetrical; each module is also provided with at least one piece of equipment from the following list: a high or medium voltage shielded substation (in English "Gas Insulated Switchgear"), a low voltage power supply panel, an energy storage system for an emergency power supply, an ambient air cooling system, a fire detection and fighting system, a refuge room; the power of each transformer is between 150 and 400 MW; said transformers have an identical power; at least one transformer has a power different from that of the other transformers;one of said modules is provided with a redundant transformer, i.e. configured to be put into service only in the event of failure of the transformer T of one of the other modules.;

[0022] Another aspect of the invention relates to an installation which comprises a plurality of wind turbines and at least one substation according to one of the preceding characteristics.

[0023] According to the particular characteristics of this installation: said substation is installed "onshore", i.e. on land; said substation is installed "offshore", i.e. off the coast; said substation rests on a foundation, on a floating support, or on the seabed; said substation rests on a "jacket" or monopile type foundation; the modules of said substation are installed on the same support or on at least two supports; at least one module of said substation is installed "onshore", i.e. on land, while the other module(s) is (are) installed offshore, i.e. off the coast.

[0024] Finally, a final aspect of the invention concerns a method for installing a substation on an "offshore" site according to one of the characteristics listed above.

[0025] According to particular characteristics of this process: said modules are connected to land and all of these modules are transported and installed on said site; each of said modules is transported and installed individually and they are connected on said site. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Other features and advantages of the invention will become apparent from the following description of a preferred embodiment of the invention. This description is made with reference to the appended drawings in which: there figure 1 is a simplified perspective view of three exemplary embodiments of a substation in accordance with the invention; figure 2 is a perspective view of an exemplary embodiment of a module which forms an integral part of the substation of the invention; figure 3 is a view similar to the previous one, the module being shown while it is fitted with optional additional equipment; the figure 4is also a perspective view of the module of the figure 3 , seen from a different direction; the Figure 5 is a perspective view of a substation comprising two modules such as that shown in figure 2 ; there figure 6 is a view similar to the previous one, the modules being provided with said additional equipment; the figures 7 And 8 are views analogous to the figures 5 And 6 respectively, the number of modules being here equal to three; the figure 9 is a diagram showing, seen from above, the arrangement of the parts of a module; the figures 10 And 11 are diagrams showing, seen from above, the arrangement of the parts of a substation comprising two, respectively three modules. DETAILED DESCRIPTION OF THE INVENTION

[0027] As indicated above, the present description is given more particularly in relation to the field of “offshore” applications, that is to say in which the substation according to the invention is located off the coast.

[0028] However, unless otherwise stated, what will be said below also applies to an application in which the substation of the invention is located on land, i.e. "onshore".

[0029] To the figure 1 attached are shown three substations 1A, 1B and 1C in accordance with the present invention.

[0030] These substations are installed "offshore", that is to say off the coast and close to a wind farm, which has not been shown for better reading of the figure.

[0031] Substation 1A visible on the left of the figure comprises two modules 3 which rest on a platform, itself located at the top of a foundation 2A which is commonly called, in trade terms, a "jacket". Usually, the height of this platform is sufficient for the substation to be well above sea level M.

[0032] The term "jacket" is commonly used to refer to a "pylon" type foundation. It generally consists of a set of four legs that extend upwards, each with a leg having the same oblique orientation forming an acute angle with respect to the vertical, so as to form an assembly resembling the structure of a derrick.

[0033] Substation 1B, which is visible in the middle of this figure, is of the same type as the previous one, but differs from it in that it has not two but three modules 3 of the same type as those of substation 1A. Foundation 2B is of the same type as foundation 2A.

[0034] As for substation 1C, which also includes three modules 3, it has a floating type 2C foundation intended to be installed in deeper waters. The person skilled in the art will know how to choose the most appropriate foundation.

[0035] In an embodiment not shown, the substation may rest directly on the seabed.

[0036] Of course, the number of modules is not limited to two or three (as is the case in the figure 1 ). It may be higher.

[0037] To the figure 2a possible example of the embodiment of a module 3 constituting the substation of the invention is shown.

[0038] Of course, this is just an example of implementation, so other forms of modules can be considered.

[0039] The module shown here is part of a rectangular parallelepiped. It is essentially formed of a metal structure 30 made up of sheets, stiffeners and profiles. Such a structure is particularly efficient, especially in terms of rigidity.

[0040] Here, the module is organized on three levels or floors N1, N2 and N3. Of course, this number could be different (lower or higher).

[0041] The internal layout of such a module will be detailed later in the description.

[0042] On the figure 2, we note the presence of two staircases 31 which are placed on either side of module 3 and which allow operators to move indifferently from one level to another.

[0043] In the example shown, levels N2 and N3 occupy a surface area smaller than that of the lower level N1, so as to clear a platform 32 on the upper surface of the latter.

[0044] We also note the presence of maintenance hatches 33 and 34 which open onto the upper surface of the highest level. These maintenance hatches will be closed in use by panels not shown.

[0045] Also noted is the presence of a 37a crane support.

[0046] For purely indicative purposes, such a module 3 may have the following dimensions: length: 29.5 meters; width (not including stairs 31): 14 meters; height: 12 meters.

[0047] As for its weight, considered when the module is fitted out and equipped with all the devices that allow it to operate, it can be in the order of 1000 tonnes.

[0048] The module of figures 3 And 4 is the same as that of the figure 2 . However, as depicted here, it is equipped with optional hardware.

[0049] Thus, we note the presence of a reactive compensator 35 (in English "shunt reactor"), which has the function of controlling the voltage of an electrical network by compensating the capacitive behavior of a network by its inductive behavior which is placed on the aforementioned platform 32 and is protected by a peripheral fence. We also note the presence in the upper part of a maintenance hatch which is closed in use by a panel not shown. We also note, at the opposite end, the presence of a roof 36 for protecting radiators 360.

[0050] This roof 36 serves as a support for an emergency electric generator 38 and a harmonic filtration system 39.

[0051] Note the presence on support 37a of a lifting crane 37 with a lifting capacity adapted to the needs of the substation.

[0052] With such optional equipment, the basic shape and dimensions of Module 3 remain unchanged. However, and still for purely indicative purposes, its weight can then be as high as 1,200 tonnes.

[0053] To the Figure 5 a possible embodiment of an electrical substation 1A according to the invention is visible.

[0054] It is here made up of two modules 3 such as that of the figure 2These modules are identical, in the sense that they have an identical shape and external dimensions, but also identical structural elements (bridges, partitions, reinforcements, etc.), both in their arrangements and in their dimensions (nature / quality of materials, thicknesses, inertia modulus, etc.) necessary for the structural resistance of the substation.

[0055] As will be seen later in the description, each module contains at least one electrical transformer configured to raise the voltage of the electricity produced by the wind farm or to lower the voltage coming from the network and allowing the wind turbines to be powered during maintenance periods.

[0056] According to the invention, these modules are connected to each other in such a way as to be able to provide an overall electrical power equal to the sum of the powers of each transformer. Thus, the number n of modules required is determined according to the unit (individual) power of each of the modules and the overall electrical power required.

[0057] In the case shown here, the two modules 3 are contiguous. In a different embodiment, the modules could not be contiguous but on the contrary separated.

[0058] Similarly, substation 1A shown in figure 6 consists of two modules 3 such as those of the figure 3 , that is to say with their optional equipment. However, we note the presence of only one crane 37. But if this proves necessary, a second crane can be provided on module 3 which is devoid of one here.

[0059] To figures 7And 8 two analogous stations 1B are represented, formed from three modules 3 identical to those described previously.

[0060] Of course, one could consider having a greater number of modules 3, but this situation has not been shown in the figures so as not to clutter them unnecessarily.

[0061] To the figure 9 schematically represents the arrangement 4 of the parts of a module 3 such as that which was described previously.

[0062] Again, this is an example, so other types of layout can be considered.

[0063] Only the layout of the aforementioned N1 level is shown here.

[0064] We are therefore dealing, in reference to the figure 9 , to a set of six rooms 40 to 45 served by the same interior corridor 5.

[0065] The fact that this corridor is placed inside the module allows operators to move safely from one room to another, without having to exit the module each time.

[0066] In the configuration presented, parts 40 to 45 have the functions detailed below.

[0067] Room 40 houses the aforementioned transformer T. This transformer is connected to some of the wind turbines in the wind farm.

[0068] Room 41 houses a medium voltage shielded panel.

[0069] Room 42 houses the low-voltage system.

[0070] Room 43 houses a second low-voltage system redundant to the first.

[0071] Room 44 houses a high-voltage shielded panel.

[0072] Room 45 is a room that houses the firefighting system and the air conditioning system.

[0073] The presence of the T transformer in a closed room allows its lifespan to be significantly increased, compared to known substations in which the transformer, although protected, is located outside and is therefore subject to climatic hazards.

[0074] To the figure 10 The layout of the rooms of a 1A substation consisting of two 3 modules is shown schematically. Again, the representation is limited to the main level N1.

[0075] Advantageously, this arrangement is strictly the same for both modules 3. Under these conditions, the construction of the modules 3 and the layout of their interior space can be rationalized.

[0076] In an embodiment not shown, the arrangements of the parts of a first and a second module 3 are reversed, so that when they are positioned next to each other, their respective parts are symmetrical. Thus, this configuration makes it possible, where appropriate, to more easily connect the parts of the same function which belong to these two different modules.

[0077] The following premises may be provided on the other floors: control, supervision and data acquisition room; room for an auxiliary (i.e. emergency) transformer and earthing; emergency generator room; safety shelter; workshop; warehouse.

[0078] In addition, a helicopter landing area and a radar mast can be provided on the roof of the upper level.

[0079] There figure 11 differs only from the figure 10by the fact that we are dealing with three identical modules 3.

[0080] In the substations of the invention, the transformers T preferably have an identical power P. However, it is possible to envisage that at least one transformer has a power different from that of the other transformers.

[0081] In addition, at least one of the modules can be provided with a redundant T transformer, i.e. configured to be put into service only in the event of failure of the T transformer of one of the other modules.

[0082] As already stated above, the substation of the invention is preferably installed "offshore", i.e. off the coast, but it can be installed "onshore", i.e. on land.

[0083] Furthermore, the 3 modules of the substation are advantageously installed on the same support, but can also be installed on at least two supports.

[0084] Thus, at least one module 3 of the substation can be installed "onshore", i.e. on land, while the other module(s) 3 is (are) installed offshore, i.e. off the coast.

[0085] For the installation on an "offshore" site of a substation conforming to the invention, it is of course possible to envisage making the connection between the modules 3 on land and transporting and installing all of these modules on the site.

[0086] But we can also consider transporting and installing each of the 3 modules individually and connecting them on site.

[0087] Advantageously, each of the modules 3 can provide a power of between 150 and 400 MV and even more preferably between 200 MW and 300 MW, these modules, when connected together, forming a "global module" of higher power. For example, it is possible to obtain a substation of 300 MW to 600 MW by connecting two modules, a substation of 600 MW to 900 MW by connecting three modules, etc.

[0088] Each module 3 (for example from 200 MW to 300 MW) is designed to be able to receive any electrical equipment from the range in question. This can occasionally generate, for the lower part of the range, an oversizing of the structure, this being largely offset by the gains made throughout the process, particularly in studies, industrialization, manufacturing and installation. In addition, each module 3 being previously certified, it is possible to significantly save on the manufacturing time (in studies in particular) which presents a major advantage for industrial operators who systematically seek to reduce the time between the start of the investment and the commissioning of the installation, which initiates the return on investment.

[0089] Using identical modules allows for the development of a mass production process, which is by definition more efficient in terms of cost, quality and lead time than a substation manufacturing process consisting of a single unit. Since the integration of additional equipment (specific to the environmental conditions of the wind farm or to the specific requirements of the client) can be planned from the design and development of the manufacturing process in the form of options, their integration into each module is compatible with mass production.

[0090] In terms of on-site installation, the solution according to the invention also makes it possible to adapt, in real time, to the least expensive installation means available on the market, by authorizing either an onshore connection of the modules 3 (which requires the use of a heavy offshore lifting means - for example 4,000 tonnes - but with a short operating time), or an offshore connection of the modules (which requires the use of a less heavy lifting means, but with a longer operating time at sea).

[0091] Of course, throughout the present application including the claims, the terms "connection of the modules", "the modules are connected to each other" and other equivalent expressions mean an electrical connection as well as, possibly, a mechanical connection depending on the arrangement of the modules in the wind farm.

Claims

1. An electrical sub-station for a wind farm (1A, 1B, 1C), which is configured to raise or lower the voltage of the electricity produced by wind turbines of said wind farm in order to ensure its conveyance to a distribution grid, characterized by the fact that it includes n modules (3), n being an integer at least equal to 2, these modules (3), each including an arrangement (4) of several rooms (40-45), having identical shape and external dimensions, each module (3) containing at least one electrical transformer (T) configured to raise or lower said voltage, these modules (3) being connected to each other so as to be able to provide to said grid an overall electrical power equal to the sum of the powers of each transformer (T).

2. The electrical sub-station (1A, 1B, 1C) according to claim 1, characterized by the fact said arrangement (4) is the same from one module (3) to another.

3. The electrical sub-station (1A, 1B, 1C) according to claim 1, characterized by the fact that the arrangements of a first and a second module (3) are reversed so that, when positioned next to each other, all or part of their respective rooms (40-45) are symmetrical.

4. The electrical sub-station (1A, 1B, 1C) according to any of the preceding claims, characterized by the fact that each module (3) is also provided with at least one equipment from the following list: a high- or medium-voltage switchgear i.e. a Gas Insulated Switchgear, a low-voltage power supply board, an energy storage system for a backup power supply, an ambient air cooling system, a fire detection and firefighting system, shelter premises.

5. The electrical sub-station (1A, 1B, 1C) according to any of the preceding claims, characterized by the fact that the power P of each transformer (T) is comprised between 150 and 400 MW.

6. The electrical sub-station (1A, 1B, 1C) according to any of the preceding claims, characterized by the fact that said transformers (T) have an identical power P.

7. The electrical sub-station (1A, 1B, 1C) according to any of the claims 1 to 5, characterized by the fact that at least one transformer (T) has a different power from that of the other transformers (T).

8. The electrical sub-station (1A, 1B, 1C) according to any of the preceding claims, characterized by the fact that one of said modules (3) is provided with a redundant transformer (T), i.e. configured to be put into service only in case of failure of the transformer (T) of one of the other modules.

9. A facility which includes a plurality of wind turbines and at least one sub-station (1A, 1B, 1C) according to any of the preceding claims, characterized by the fact that said sub-station (1A, 1B, 1C) is installed onshore.

10. A facility which includes a plurality of wind turbines and at least one sub-station (1A, 1B, 1C) according to any of claims 1 to 8, characterized by the fact that said sub-station (1A, 1B, 1C) is installed offshore.

11. The facility according to claim 10, characterized by the fact said sub-station (1A, 1B, 1C) rests on a foundation (2A, 2B), on a floating support (2C) or on the seabed.

12. The facility according to claim 11, characterized by the fact said sub-station (1A, 1B, 1C) rests on a "jacket"-type foundation or monopile.

13. The facility according to any of claims 10 to 12, characterized by the fact that the modules (3) of said sub-station (1A, 1B, 1C) are installed on the same support or on at least two supports.

14. A facility which includes a plurality of wind turbines and at least one sub-station (1A, 1B, 1C) according to any of claims 1 to 8, characterized by the fact that at least one module (3) of said sub-station (1A, 1B, 1C) is installed onshore while the other module(s) (3) is / are installed offshore.

15. A method for setting up, on an offshore site, a sub-station (1A, 1B, 1C) according to any of claims 1 to 8, characterized by the fact that said modules (3) are connected onshore and that all of these modules (3) are transported and installed on said site.

16. A method for setting up, on an offshore site, a sub-station (1A, 1B, 1C) according to any of claims 1 to 8, characterized by the fact that each of said modules (3) is transported and installed individually and that the connection of these modules is carried out on said site.