Ocean in-sea power distribution

Abstract

The marine power distribution system 100 comprises a plurality of first cables 1a-n having first dry-coupled connections 2b and connected to the marine generator units 7, a subsea junction box 3, a second cable 5 extending from the junction box 3 to a subsea substation 6, the second cable having a second dry-coupled connection 10a terminating inside the junction box 3 operably connected to the first dry-coupled connections 2b and extending to the subsea substation 6, and a third cable 12 extending from the substation 6 to an onshore power receiver 8, transmitting power from the marine generator units 7 via the first, second, and third cables to the onshore power receiver 8. Methods of installing the marine power distribution system 100 and methods of distributing power in the marine power distribution system 100 are also provided.

Description

Technical Field

[0001] The present invention relates to marine power distribution and, in particular, to systems and methods for distributing power to (or from) marine generators or power consumers, and to the installation of associated marine power generating facilities and subsea cables therefor, and to the temporary removal of marine structures from an array of connected structures.

Background Art

[0002] Marine power generation is expanding in scale, and the development of renewable resources such as offshore wind or wave power is seen as making a significant contribution to the supply of clean energy for the future. For example, offshore wind is an established technology, and floating wind energy converters are currently being researched and developed by various research and development (R&D) groups both within the academic and industrial communities, thereby greatly expanding the available areas suitable for offshore wind power generation. Other technologies being researched by various groups are wave and tidal power generation systems.

[0003] Published patents that may be useful for understanding the background include WO2019 / 141841A1, WO2009 / 131826A2, WO2013 / 110276A1, and WO2013 / 050755A2.

[0004] Increased investment in future marine power generation is planned and ongoing, and further technological improvements for marine power distribution are needed. The present disclosure aims to provide such improvements or at least alternatives to the current state of the art.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

[0006] In an embodiment, a plurality of first cables, each first cable having a first dry mate connection at its first end and being connected to an ocean generator unit at its second end; a subsea junction box disposed on the seabed, each dry mate connection terminating inside the junction box; a second cable extending from the junction box to a subsea substation disposed on the seabed, the second cable having a second dry mate connection at its end, the second dry mate connection terminating inside the junction box where it is operably connected to the first dry mate connection, the second cable extending to the subsea substation disposed on the seabed and being operably connected to the substation; and a third cable extending from the substation to an onshore power receiver, are provided, and an ocean power distribution system configured to transmit power from the ocean generator unit to the onshore power receiver via the first, second, and third cables is provided.

[0007] In an embodiment, a method of installing an ocean power distribution system includes steps of installing a plurality of generators, each generator having a first cable with a first dry mate connector at its first end; installing a subsea substation on the seabed and a third cable extending from the substation to an onshore power receiver; installing a subsea junction box on the seabed; connecting the subsea junction box and the substation to a second cable; and connecting the first cable to the second cable, including establishing a dry mate connection between the first cable and the second cable inside the junction box.

[0008] In an embodiment, there is provided a method of distributing power in an ocean power distribution system, including the steps of operating the ocean power distribution system, retrieving a junction box from the seabed to a ship, performing installation, removal, or operation work at the junction box, and reinstalling the junction box to the seabed.

[0009] In an embodiment, an assembly for supplying power to or from a subsea structure, wherein the subsea structure has a pressure-resistant housing, and the assembly comprises the subsea structure and a power cable, the power cable comprising a continuous metallic watertight sheath enclosing at least one conductor, the watertight sheath being sealed and terminated at a flange of the housing, at least one conductor extending through the flange into the interior of the housing, an assembly is provided.

[0010] In an embodiment, a method of operating a floating power generation facility, including the steps of mooring the power generation facility to the seabed with a plurality of mooring cables fixed to seabed anchors, connecting at least one subsea cable having a slack to the floating power generation facility, operating the power generation facility while temporarily retaining the slack at or adjacent to the power generation facility, wherein the slack of the subsea cable is configured to correct a horizontal displacement of the power generation facility in association with the remaining portion of the subsea cable, such that during breakage of any one of the plurality of mooring cables, the remaining portion remains stationary and the subsea cable remains operational. A method is provided.

[0011] In an embodiment, a floating power generation facility includes a floater, a mooring cable extending from the floater to an anchor on the seabed, and a subsea cable having a slack length and connected to the power generation facility. The slack length of the subsea cable is retained at or adjacent to the power generation facility and is configured to correct the horizontal displacement of the power generation facility in association with the remaining portion of the subsea cable. Thereby, during the breakage of any one of the plurality of mooring cables, the remaining portion remains stationary and the subsea cable remains operational, and a floating power generation facility is provided.

[0012] In an embodiment, a method for temporarily removing a marine power generation unit from an array of connected marine power generation units includes the steps of removing input-side and output-side array cables from the marine power generation unit, providing a junction box having an inlet connection point and an outlet connection point, connecting the input-side cable to the inlet connection point and the output-side cable to the outlet connection point, disposing the junction box at a position in the sea, using support means to position the junction box at a position below the water surface with the input-side array cable attached to the input-side connection point and the output-side cable attached to the output-side connection point, and removing the input-side and output-side array cables from the inlet and outlet connection points respectively and reconnecting the input-side and output-side array cables to the marine power generation unit again.

[0013] In an embodiment, a junction box for temporarily connecting to an array of marine power generation units is provided, which includes a housing having an inlet connection point and an outlet connection point. The inlet connection point communicates with the outlet connection point via an internal cable disposed inside the housing, and the housing is provided with a lifting engagement device for connecting lifting means. The inlet and outlet cables are provided at the inlet and outlet connection points and can be lifted through the engagement of the lifting means with the lifting engagement portion.

[0014] The appended claims and the following detailed description outline further embodiments.

[0015] These and other features will become apparent from the following description of exemplary embodiments given as non-limiting examples with reference to the accompanying drawings.

Brief Description of the Drawings

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DETAILED DESCRIPTION OF THE INVENTION

[0017] The following description may use terms such as "horizontal direction", "vertical direction", "lateral direction", "front and back", "up and down", "upper side", "lower side", "inner side", "outer side", "front", "rear", etc. These terms generally refer to the viewpoints and directions shown in the drawings and are related to the normal use of the present invention. The terms are used for the convenience of the reader and are not limiting.

[0018] As used herein, the term "submarine cable" is intended to represent any type of cable, such as, for example, a single-core, two-core, or three-core power cable, a radial field or mass shield power cable, or any other conductive or non-conductive cable or cord routed from the nacelle of a wind turbine to the tower, such as a control cable.

[0019] By way of example and context, FIGS. 1 and 2 illustrate one possible configuration that may be suitable for use with the power distribution methods, systems, and arrangements of the present disclosure. However, it will be understood that the distribution methods and arrangements do not depend on the exact design of other system components such as the floater and the subsea portion, and they may have designs different from those described in the following examples.

[0020] FIG. 1 illustrates an ocean power generation unit 7a suitable for use with an embodiment of the present disclosure. The power generation unit 7a of FIG. 1 is a floating wind turbine or a floating wind energy power generation facility. Other types of power generation units suitable for use with an embodiment of the present disclosure include bottom-fixed wind turbines, generators that utilize tidal current, wave power, solar, or nuclear energy, or any other type of ocean power generation unit.

[0021] The floating wind energy power generation facility 7a includes a floater 10 and a wind turbine 20. The wind turbine 20 may be of a conventional design having a tower 21, a nacelle 23, and blades 25.

[0022] The floater 10 includes three columns 11, 13, 15. Each of the columns 11, 13, 15 is connected to at least two of the other columns 11, 13, 15. In some embodiments, there may be more than three columns, such as four, five, or six columns, in the floater 10.

[0023] Each column 11, 13, 15 has a lower part configured to sink at the operating position of the float 10 in association with column 15. Each column 11, 13, 15 is connected at the lower part of each respective column 11, 13, 15 to at least two of the other columns. This connection may be by means of a substantially horizontal connecting member.

[0024] Figure 2 illustrates an ocean power distribution system 100 according to an embodiment. The system 100 includes a plurality of array cables 1a - n for sending power from several power generation units 7. Figure 3 schematically illustrates an array cable 1a. Each array cable 1a - n has a dry connection connector 2b at the first undersea end 9b of the cable. The second upper ends 9a of the array cables 1a - n are each connected to a respective ocean generator unit 7 by a connector 2a.

[0025] In Figure 2, each generator unit 7 has its dedicated array cable 1a - n. Optionally, there may be more than two generator units 7 connected in a daisy chain, and in that case, the array cables 1a - n here refer to the cables extending from the generator units 7 at the ends of the chain, through which power is passed from other daisy - chain - connected generator units 7.

[0026] Referring to Figure 2, a subsea junction box 3 is disposed on the seabed 4. In this embodiment, two junction boxes 3 are used, but one junction box 3 or more than two junction boxes may be used. Each dry connection connector 2b of each array cable 1a - n terminates inside the junction box 3 in this example. However, in an example where the generator units 7 are daisy - chain - connected together, fewer cables (e.g., one cable) may connect the daisy - chain - connected generator units 7 to the junction box 3, while other array cables may connect between the generator units 7.

[0027] The intermediate cable 5 extends from the junction box 3 to the offshore substation 6 disposed on the seabed 4. FIG. 4 schematically illustrates the intermediate cable 5. The intermediate cable 5 has a dry connection connector 10a at one end 11a of the cable and another connector 10b at the other end 11b. The other connector 10b may be a dry connection connector similar to the connector 10a or of a different type. The dry connection connector 10a terminates inside the junction box 3 and is operably (i.e., electrically) connected to the dry connection connectors 2b of the array cables 1a~n. The intermediate cable 5 is thus arranged to transmit the power supplied by the array cables 1a~n.

[0028] The intermediate cable 5 also extends from the junction box 3 to the offshore substation 6 disposed on the seabed 4. The intermediate cable 5 thus transmits power from the array cables 1a~n to the substation 6 to which it is operably connected.

[0029] The export cable 12 extends from the substation 6 to the onshore receiver 8. The export cable 12 is arranged to transmit the power received from the intermediate cable 5 from the substation 6 to the onshore receiver 8. The onshore receiver can be, for example, an onshore power grid, an energy storage facility, a power consumer, etc.

[0030] The power distribution system 100 is thus configured to transmit power from the ocean power generation unit 7 to the onshore receiver 8 via the array cables 1a~n, the junction box 3, the intermediate cable 5, the substation 6, and the export cable 12.

[0031] The substation 6 is configured to increase the voltage of the power received from the intermediate cable 5 and then supply the power to the export cable 12. The export cable 12 thus operates at a higher voltage than the intermediate cable 5. Advantageously, the cross-section of the conductors in the export cable 12 is smaller than that of the conductors in the intermediate cable 5. Nevertheless, for example, when the export cable 12 is very long or when several intermediate cables 5 supply a single export cable 12 as in the example shown in FIG. 2, the cross-section of the export cable 12 can be the same as or larger than that of the intermediate cable 5.

[0032] In any embodiment, the array cables 1a - n and the intermediate cable 5 can be configured to operate at the same voltage. In that case, the voltage in the junction box 3 does not substantially change.

[0033] In any embodiment, the designed operating voltage for the array cables 1a - n and the intermediate cable 5 can be, for example, above 30 kV, above 40 kV, or above 65 kV.

[0034] FIG. 5 illustrates another embodiment having three power generation units 7a - c. The other components are equivalent to those described above.

[0035] It will be understood that many other configurations of the ocean power generation system are possible, for example, having floating wind turbines of different designs, other types of power generation facilities, different numbers of power generation facilities (from one to many), etc. However, for the purposes of this description, it is assumed that the power generation facility is a floating wind energy power generation facility.

[0036] FIG. 6 illustrates a further embodiment having eight power generation units 7a - h and respective array cables 1a - h each extending to the junction box 3. The other components are equivalent to those described above.

[0037] Figure 7 illustrates the electrical wiring diagram / connection diagram for the embodiment shown in Figure 6. Each of the power generation units 7a - h may include a power conditioning component 31 as required. The power conditioning component 31 may include a power switch as will be described in more detail below.

[0038] Figures 8 and 9 illustrate examples of the junction box 3 suitable for use with the embodiments described herein. As indicated in Figure 8, the junction box 3 may include an internal connector / connection part and also fuses as will be described in more detail below. As can be seen in Figure 9, the junction box is recoverable from the ship to the sea surface.

[0039] As illustrated in Figure 10, the junction box 3 includes connectors 10a (connecting the intermediate cable 5 extending to the substation 6) and 2b (connecting the array cables 1a - n (illustrated here by two array cables 1a, 1b) coming from the power generation unit 7). In addition, the junction box 3 may include respective fuses 33, 34. The fuses 33, 34 may be arranged to disconnect the connection between one or more of the array cables 1a - n and the intermediate cable 5, for example, in case of overload. There may be a fuse 34 operable to disconnect the connection between the intermediate cable 5 and all of the array cables 1a - n. In addition or alternatively, there may be individual fuses 33 that are operable to connect to each of the array cables 1a - n and disconnect the connection between each of the array cables 1a - n and the intermediate cable 5, while maintaining the connection between the other array cables 1a - n and the intermediate cable 5.

[0040] As can be most clearly shown in FIG. 9, the junction box 3 is recoverable from the ship to the sea surface. In some examples, the junction box 3 may include a load-bearing device therein, whereby, in some situations, for example when the junction box 3 and the connected wiring are lifted, it can assist in supporting the weight of the wiring. The load-bearing device may include load-bearing terminations disposed on each of the array cables 1a, 1b disposed inside the junction box 3. The load-bearing termination may be, for example, a pull head having a hang-off interface. The load-bearing device may function to transfer the load from the array cables 1a, 1b to the junction box 3. In this way, for example, when the junction box 3 is lifted by the array cables 1a, 1b attached thereto, the junction box 3 may be capable of bearing a load equivalent to the weight of the array cables.

[0041] As can be most clearly shown in FIGS. 9 and 25, the junction box 3 may be attachable to a crane or a winch, thereby facilitating the holding of the junction box 3 on the ship and, in addition, facilitating the raising and lowering of the junction box to or from a position in the sea. The method described may thus include the attachment of the junction box to a support means such as a crane, cable, or winch. This is done by connecting the ship's crane hook or winch wire to the fore runner or similar of the junction box 3. The junction box 3 can then be taken out to or lowered from a position on the sea surface (e.g., the ship's deck), for example, through the ship's moon pool (if any) or to / from a workbench or similar along the ship's side.

[0042] FIG. 11 shows an example of a transformer unit 6 disposed on the seabed having an export cable 12 connected thereto (the intermediate cable 5 is not shown here).

[0043] Figures 12 to 15 illustrate various steps in the installation method according to the embodiment. As shown in FIG. 12, a plurality of generator units 7 can be installed in the ocean, for example, by mooring to the seabed or by fixed installation on the seabed. Each generator 7 has array cables 1a to n for transmitting power, and each array cable has a dry connection connector 2b at its end (see FIG. 3). The other ends of the cables 1a to n are fixed and operably connected to the generator unit 7, for example, at the tower or nacelle of the generator unit 7. The dry connection connector 2b can be left underwater on the seabed during the installation of the generator unit 7 and the array cables 1a to n.

[0044] In FIG. 13, the offshore substation 6 is installed on the seabed by a ship 20. As shown in FIG. 14, an export cable 12 is further installed, and the export cable 12 extends from the substation 6 to the onshore receiver 8.

[0045] Advantageously, the export cable 12 is dry-connected to the offshore substation 6 before installation, and the substation 6 and the export cable 12 are installed in the same operation. This eliminates the need to make a wet connection between the export cable 12 and the substation 6 or to recover the substation 6 to connect the export cable 12 after installation. In such a case, depending on the desired installation method, the combined arrangement of the substation 6 and the export cable 12 can start in the ocean with the substation 6 and end with the landing of the export cable 12, or vice versa, starting with the landing of the export cable 12 and ending with the deployment of the substation 6.

[0046] Advantageously, the intermediate cable 5 may also be dry-connected to the offshore substation 6 before installation, and the intermediate cable 5 and the substation 6 can be installed in the same operation. This eliminates the need to make a wet connection between the intermediate cable 5 and the substation 6 or to recover the substation 6 to connect the intermediate cable 5 after installation.

[0047] Advantageously, the intermediate cable 5 can be arranged on the seabed in parallel with the sea ends of the cables 1a to n. This is illustrated in FIG. 14, where the connectors 2b and 10a are held underwater adjacent to each other on the seabed. This can simplify the installation of the junction box 3 described below. Optionally, the end portions 35 of the array cables 1a to n and the end portion 36 of the intermediate cable 5 (see FIG. 14) arranged in parallel have a length exceeding the water depth at that location. This enables more controlled recovery of the connectors 2b, 10a and the end portions 35, 36 in that the parallel portions 35, 36 can be lifted up and down together by a ship, reducing the risk of entanglement.

[0048] As shown in FIG. 15, the method further includes the steps of installing a subsea junction box 3 on the seabed and laying an intermediate cable 5 to interconnect the subsea junction box 3 and the substation 6. In addition, the array cables 1a to n are operably connected to the intermediate cable 5 inside the junction box 3 by establishing a dry connection between the array cables 1a to n in the junction box 3 and the intermediate cable 5.

[0049] As described above, the method may include the steps of retrieving the dry connection connectors 2b of the array cables 1a to n from the seabed when they are held underwater and establishing a dry connection inside the junction box 3 on the ship 20. The intermediate cable 5 may also be held underwater after installation, and the method may therefore also include the step of retrieving the dry connection portion 10a of the intermediate cable 5 before establishing the dry connection in the junction box 3.

[0050] The connection of the array cables 1a to n to the intermediate cable 5 can be performed in parallel or one by one depending on whether one or more of the array cables 1a to n are taken out onto the deck together with the intermediate cable 5. The array cables 1a to n can optionally be taken out one by one.

[0051] After connecting the array cables 1a - n and the intermediate cable 5 in the junction box 3, the junction box 3 to which the cables 1a - n and 5 are connected is lowered to the seabed. When the process is carried out continuously in steps for different array cables 1a - n, the next array cables 1a - n can optionally be retrieved for connection to the junction box 3. In that case, the process can be repeated until all the array cables 1a - n are connected to the intermediate cable 5 and the configuration of the junction box 3 is completed. The retrieval of one or more of the array cables 1a - n can instead be carried out by a second ship if available and then transferred to the main ship by means of a wet hand - shake or similar method.

[0052] Optionally, the cable ends 2b, 10a can be arranged in a retrieval frame in the sea in order to retrieve two or more (or all) of the array cables 1a - n and the intermediate cable 5 onto the deck at once. The retrieval frame is then retrieved onto the deck by the same steps for a single cable connection, and the connection between the array cables 1a - n and the intermediate cable 5 can be made in parallel.

[0053] As described above, the offshore substation 6 can be installed with the intermediate cable 5, with the transformer end connector 10b of the intermediate cable 5 (see FIG. 4) being pre - installed in the substation 6 prior to deployment. Additionally or alternatively, the offshore substation 6 can be installed with the export cable 12 or a portion of the export cable 12 (e.g., the "end") being pre - installed in the substation 6, such that the connection is thereby made continuously between the end and each of the export cable 12 and / or the intermediate cable 5. This can be a dry - type connection established by retrieving the end and the ends of each of the export cable 12 and / or the intermediate cable 5 and connecting them, for example, on the deck of a ship.

[0054] As will be appreciated, the different steps of the method can be varied. For example, the cable ends can be left in the water in the middle in order to execute the method most effectively, for example, in terms of whether a work vessel is available at any given time or within a given weather window.

[0055] Advantageously, the systems and methods according to embodiments of the present disclosure enable more flexible operation and easier maintenance of marine power distribution systems. For example, when adopting the subsea power distribution system 100, the junction box 3 can be retrieved by a vessel at a later time for maintenance, repair, replacement, etc.

[0056] In use, a method of operating the marine power distribution system 100 can thus include retrieving the junction box 3 from the seabed to the vessel 20 and reinstalling the junction box 3. This can be done, for example, to replace the fuses 33, 34 in the junction box 3, or to add or remove the generator unit 7 from the system.

[0057] The embodiments can further provide more cost - competitive power distribution through bottleneck breakthrough by using existing equipment in prominent ones, cost reduction by reducing complex components (e.g., standardization of cable design), and reduction of maintenance costs. Compared with some alternatives, the embodiments herein can reduce the number of pressure - sensitive components disposed in the sea.

[0058] In the above embodiments, the upper and subsea connections of the array cables 1a - n are respectively made by the dry - type connection connectors 2a and 2b. Alternatively, one or both of these can be of a different type of dry - type connection. In particular, this dry - type connection can be a twisted connection. Similarly, one or both of the end connections of the intermediate cable 5 can be a twisted dry - type connection instead of one or both of the connectors 10a, 10b.

[0059] Each power generation unit 7 may have respective power switches disposed thereon (for example, in the case of a floating wind turbine such as that illustrated in FIG. 1, the power switch may be disposed on the floater, or on the turbine tower or nacelle). The power switch may be operable to disconnect each power generation unit 7 from its array cables 1a-n.

[0060] Advantageously, the system may be arranged such that none of the array cables 1a-n, the subsea junction box 3, the second cable 5, and the substation 6 have power switches. By providing power switches within the power generation units 7 and not in the aforementioned subsea components, the risk of out-of-operation time or failure can be reduced (a "power switch" is a selectively operable switch or switching mechanism, i.e., one by which an operator can connect or disconnect an electrical connection, and is distinct from (passive and automatic) fuses 33, 34).

[0061] Advantageously, the system may be arranged such that none of the array cables 1a-n, the subsea junction box 3, and the second cable 5 have wet-mate connectors.

[0062] Advantageously, the export cable 12 may be configured for operation at a voltage of 132 kV or higher.

[0063] Various further aspects and examples of the present disclosure may be summarized in the following items.

[0064] Item A1. A plurality of first cables (1a-n), each first cable (1a-n) having a first dry-mate connection (2b) at its first end (9b) and being connected to an offshore power generation unit (7) at its second end (9a). An undersea junction box (3) disposed on the seabed (4), wherein each dry connection joint (2b) terminates inside the junction box (3), and the undersea junction box, A second cable (5) extending from the junction box (3) to an undersea substation (6) disposed on the seabed (4), having a second dry connection joint (10a) at its end (11a), and the second dry connection joint (10a) terminates inside the junction box (3) operably connected to the first dry connection joint (2b), A second cable extending to an undersea substation (6) disposed on the seabed (4) and operably connected to the substation (6), A third cable (12) extending from the substation (6) to an onshore receiver (8) and comprising, An ocean power distribution system (100) configured to send power from an ocean generator unit (7) to an onshore receiver (8) via the first, second, and third cables.

[0065] Item A2. The first dry connection joint (2b) is a dry connection connector (2b), or a twisted connection part The ocean power distribution system (100) according to Item A1.

[0066] Item A3. The second dry connection joint (10a) is a dry connection connector (10a), or a twisted connection part The ocean power distribution system (100) according to Item A1 or A2.

[0067] Item A4. The third cable (12) is configured to operate at a higher voltage than the first cable (1a~n) and the second cable (5). The ocean power distribution system (100) according to any one of Items A1 to A3.

[0068] Item A5. The marine power distribution system (100) according to any one of Items A1 to A4, wherein the first cable (1a to n) and the second cable (5) are configured to operate at the same voltage.

[0069] Item A6. The marine power distribution system (100) according to any one of Items A1 to A5, wherein the cross-section of the third cable (12) is smaller than the cross-section of the second cable (5) or the combined cross-section of a plurality of second cables (5).

[0070] Item A7. The marine power distribution system (100) according to any one of Items A1 to A6, wherein the subsea junction box (3) is recoverable to the sea surface.

[0071] Item A8. The marine power distribution system (100) according to any one of Items A1 to A7, wherein each of the plurality of first cables (1a to n) is operably connected to an in-line fuse (33) disposed in the junction box (3).

[0072] Item A9. The marine power distribution system (100) according to any one of Items A1 to A8, wherein the plurality of first cables (1a to n) have a design operating voltage exceeding 45 kV.

[0073] Item A10. The marine power distribution system (100) according to any one of Items A1 to A9, wherein each power generation unit (7) is provided with a respective power switch disposed on or within the power generation unit (7), and the power switch is operable to selectively disconnect each power generation unit (7) from its first cable (1a to n).

[0074] Item A11. The marine power distribution system (100) according to Item A10, wherein none of the first cable (1a to n), the subsea junction box (3), the second cable (5), and the substation (6) is provided with a power switch operable to selectively disconnect the power generation unit (7).

[0075] Item A12. The ocean power distribution system (100) according to any one of Items A1 to A11, wherein the end portions (35) of the first cables (1a to n) and the end portions (36) of the second cables (5) are arranged in parallel on the seabed (4).

[0076] Item A13. The end portions (35) of the first cables (1a to n) and the end portions (36) of the second cables (5) are arranged at a position having a certain water depth, and the end portions (35) of the first cables (1a to n) and the end portions (36) of the second cables (5) that are arranged in parallel on the seabed (4) each have a length exceeding the water depth. The ocean power distribution system (100) according to Item A12.

[0077] Item A14. A step of installing a plurality of generators (7), each generator having a first cable (1a to n) having a first dry connection connector (2b) at its own first end (9b); A step of installing a subsea substation (6) on the seabed (4) and installing a third cable (12) extending from the substation (6) to an onshore receiver (8); A step of installing a subsea junction box (3) on the seabed (4); A step of connecting the subsea junction box (3) and the substation (6) to the second cable (5); A step of connecting the first cable (1a to n) to the second cable (5), including establishing a dry connection between the first cable (1a to n) and the second cable (5) within the junction box (3). A method of installing an ocean power distribution system (100), including the above steps.

[0078] Item A15. Including a step of leaving the first dry connection connector (2b) underwater on the seabed (4), The method according to Item 14, wherein the step of connecting the first cable (1a to n) to the second cable (5) includes recovering the first dry connection connector (2b) from the seabed (4) and establishing a dry connection between the first cable (1a to n) and the second cable (5) on a ship (20).

[0079] including the step of underwaterly placing a second dry connection connector (10a) connected to a second cable (5) on the seabed (4); The method according to claim 14 or 15, wherein the step of connecting the first cable (1a-n) to the second cable (5) includes retrieving the second dry connection connector (10a) from the seabed (4) and then establishing a dry connection between the first cable (1a-n) and the second cable (5) on a ship (20).

[0080] The method according to any one of claims A14 to A16, including the step of arranging the end portion (35) of the first cable (1a-n) and the end portion (36) of the second cable (5) in parallel on the seabed (4).

[0081] The method according to claim A17, wherein the end portion (35) of the first cable (1a-n) and the end portion (36) of the second cable (5) are arranged at a position having a certain water depth, and the end portion (35) of the first cable (1a-n) and the end portion (36) of the second cable (5) arranged in parallel on the seabed (4) each have a length exceeding the water depth.

[0082] The method according to any one of claims A14 to A18, including the step of installing the offshore substation (6) with the transformer end connector (10b) of the second cable (5) pre-installed at the substation (6) together with the second cable (5).

[0083] The method according to any one of claims A14 to A19, including the step of installing the offshore substation (6) with the third cable (12) or a portion of the third cable (12) pre-installed at the substation (6) together with the third cable (12) or a portion of the third cable (12).

[0084] including the step of operating the system according to any one of claims A1 to A13; retrieving the junction box (3) from the seabed (4) to the ship (20); performing installation, removal, or operation work at the junction box (3); reinstalling the junction box (3) to the seabed (4); and A method of distributing power in an ocean power distribution system (100) including the above.

[0085] In another aspect illustrated in FIGS. 16 and 17, an assembly for supplying power to or from a subsea structure is provided.

[0086] Applications in various oceans require power transmission at high power levels. This may include ocean power generation such as the above examples where the generated power needs to be transmitted over long distances to land or to an ocean substation or directly to consumers. Other examples include ocean power supply where power is supplied from land or from an ocean generator separated from consumers to ocean consumers. This may include, for example, ocean platforms for oil exploration or production that require high power. Often, subsea terminations or interconnections are desirable or necessary for such power transmission. The aspects illustrated in FIGS. 16 and 17 are, therefore, not limited to any particular application and can be used in any type of ocean power transmission.

[0087] There are limitations regarding the voltage levels that can be used for wet-mate connectors for subsea cables. In applications at long step out distances where high power is required and / or detuning occurs, it is usually desirable to raise the voltage level as much as possible to a level where wet-mate connectors are not suitable. For voltages above about 70 kV, a "dry design" is usually required, i.e., a water barrier is provided so that the connectors for the conductors are dry. Penetrators passing through the housing of the subsea structure can be used in connectors for connecting cables to subsea structures such as substations or distribution stations or to subsea consumers such as subsea compressors. The water barrier can be used around the conductors to enable a dry design.

[0088] Figures 16 and 17 illustrate an embodiment of an assembly 200 for supplying power to or from a subsea structure. FIG. 16 shows a side view of a three-cable assembly 200 (in this embodiment), and FIG. 17 shows a top view thereof. The subsea structure can be, for example, a subsea junction box 3 or substation 6 as described above, or another type of generator, distribution unit, or consumer located subsea.

[0089] The subsea structures 3, 6 have a pressure-resistant watertight housing 201 for providing a dry environment inside the structure 205, for example, for connectors, power electronics, or other components. The assembly 200 further comprises a power cable 202 for distributing power to or from the subsea structures 3, 6. In some applications, the power cable 202 can be several kilometers in length. If necessary, the power cable can be composed of individual sections 202a, 202b that are twisted together using known methods with a cable splice 202c.

[0090] The power cable 202 comprises a continuous metallic water-blocking sheath 203 that encloses at least one conductor 204 inside the cable 202. The water-blocking sheath 203 is continuous along the cable 202 and can be disposed along substantially the entire cable 202, along the main portion of the cable 202, or around any cable splice 202c (for example, the cable 202 can extend through to a land-side facility, and the water-blocking sheath 203 can be provided along the entire cable 202 up to the "dry" termination of the ends of other cables).

[0091] The water shielding sheath 203 is sealed and terminated at the flange 201' of the housing 201. On the other hand, at least one conducting wire 204 extends through the flange 201' into the interior 205 of the housing 201. This can be done as illustrated in FIGS. 16 and 17 by separating the water shielding sheath 203 from the conducting wire 204 at the flange 201', fixing the water shielding sheath 203 to the flange 201' outside the housing 201, and arranging the conducting wire to pass through the flange 201' and proceed into the housing 201. For this purpose, the water shielding sheath 203 can be welded or soldered to the flange 201'.

[0092] The flange 201' may be a flange fixed to the housing 201 by welding (see the weld 208 in FIG. 16), or the flange 201' may be an integral part of the housing 201. The flange 201' provides an opening 210 that penetrates the wall of the housing 201 and a fixed contact surface 211 for the water shielding sheath 203, but may have any suitable shape or form otherwise.

[0093] The water shielding sheath 203 can comprise a first portion 203a and a second portion 203b, and the second portion 203b is a relay water shielding sheath portion disposed between the flange 201' and the first portion 203a. The first portion 203a can be a sheath that extends along most of the length of the cable, for example, to the termination of other cables.

[0094] A first soldering or welding portion 206 can provide a watertight connection between the second portion 203b and the flange 201', and a second soldering or welding portion 207 can provide a watertight connection between the second portion 203b and the first portion 203a.

[0095] The first portion 203a can preferably mainly consist of lead (Pb) or a lead alloy. Lead provides the advantages of easy extrusion and good resistance to seawater. However, other materials may be suitable.

[0096] The second part 203b can preferably mainly consist of copper (Cu) or a copper alloy. Soldering between the lead water-blocking part and the copper water-blocking part provides good performance, and copper can also be soldered to stainless steel, making it a good material option for the second part 203b. However, other materials may be suitable.

[0097] The flange 201' can preferably be made of a non-magnetic metal to reliably eliminate electromagnetic interference between three phases. The flange 201' can be made of a high-alloy stainless steel or a nickel-based alloy. However, other materials may be suitable.

[0098] The solder material can preferably be more expensive than both of the materials being joined.

[0099] The solder material can preferably have a melting point lower than both of the materials being joined.

[0100] The solder material can be, for example, Ag or Sn.

[0101] In the above examples of suitable materials for different parts, "mainly consisting of" means that the part is composed of each material exceeding 70%, 80%, 90%, 95%, 98%, or 99% by mass. A completely pure mixture of materials may not be strictly required.

[0102] Figure 17 indicates an example of a combination of suitable materials for different parts. However, various other materials may be suitable.

[0103] The cable 202 may comprise two or more conductors 204, wrapped by a water-blocking sheath 203. Alternatively or in addition, the assembly 200 may comprise several cables 202 that terminate in the same housing 201. This is used in the embodiments illustrated in FIGS. 16 and 17 and has three cables 202. Each power cable 202 comprises a continuous metallic water-blocking sheath 203 that wraps at least one conductor 204 in each respective cable 202. As can be seen in FIG. 17, the water-blocking sheaths 203 of the individual power cables 202 can be sealed and terminated at separate flanges 201' of the housing 201, and the conductors 204 of a given power cable 202 extend through the respective flange 201' into the interior 205 of the housing 201.

[0104] By directly terminating the water-blocking sheath 203 to the housings 201, 201', a continuous metallic water-blocking portion is provided to the flange 201' or wall of the housing 201 along the entire length of the cable 202, while the conductors 204 can be provided within the housing 201 without using either a connector or a penetrator. Thereby, problems associated with connectors, where the voltage and / or power capacity is limited, are eliminated in that the conductors 204 can be kept as continuous components through to their termination points, for example, in components within the housing 201. Thus, higher power / voltage may be made possible. Further, the cable termination system outside the housing 201 is simplified and does not include the termination of the conductors 204 at the contact surface of the cable and the housing, so that the risk of leakage or other operational problems associated with penetrators or connectors can be reduced or eliminated.

[0105] Various further aspects and examples of the present disclosure can be summarized in the following items.

[0106] Item B1. An assembly (200) for supplying power to or from a subsea structure (3, 6), wherein the subsea structure (3, 6) has a pressure-resistant housing (201), and the assembly (200) comprises the subsea structure (3, 6) and a power cable (202), The power cable (202) includes a continuous metallic water-blocking sheath (203) that wraps at least one conductor (204), the water-blocking sheath (203) is sealed and terminated at the flange (201’) of the housing (201), and at least one conductor (204) extends through the flange (201’) into the interior (205) of the housing (201). Assembly.

[0107] Item B2. The assembly according to Item B1, wherein the water-blocking sheath (203) is welded or soldered to the flange (201’).

[0108] Item B3. The assembly according to Item B1 or B2, wherein the water-blocking sheath (203) comprises a first part (203a) and a second part (203b), and the second part (203b) is an intermediate water-blocking sheath portion disposed between the flange (201’) and the first part (203a).

[0109] Item B4. The assembly according to Item B3, comprising a first soldering or welding portion (206) between the second part (203b) and the flange (201’), and a second soldering or welding portion (207) between the second part (203b) and the first part (203a).

[0110] Item B5. The assembly according to Item B3 or B4, wherein the first part mainly consists of lead (Pb) or a lead alloy.

[0111] Item B6. The assembly according to any one of Items B3 to B5, wherein the second part mainly consists of copper (Cu) or a copper alloy.

[0112] Item B7. The assembly according to any one of Items B1 to B6, wherein the flange (201’) mainly consists of a non-magnetic metal.

[0113] Item B8. The assembly according to Item B7, wherein the flange (201’) mainly consists of stainless steel or a nickel-based alloy.

[0114] Assembly according to any one of items B3 to B8, wherein the first part (203a) and the second part (203b) are provided with different materials.

[0115] Assembly according to any one of items B3 to B9, wherein the first part (203a) and the second part (203b) are both soldered by the first solder material.

[0116] Assembly according to item B10, wherein the first solder material is more precious than both of the materials to be joined.

[0117] Assembly according to item B10 or B11, wherein the first solder material has a lower melting point than both of the materials to be joined.

[0118] Assembly according to any one of items B10 to B12, wherein the first solder material mainly consists of Ag or Sn.

[0119] Assembly according to any one of items B3 to B13, wherein the second part (203b) and the flange (201’) are both soldered by the second solder material.

[0120] Assembly according to item B14, wherein the second solder material is more precious than both of the materials to be joined.

[0121] Assembly according to item B14 or B15, wherein the second solder material has a lower melting point than both of the materials to be joined.

[0122] Assembly according to any one of items B14 to B16, wherein the second solder material mainly consists of Ag or Sn.

[0123] Assembly according to any one of items B1 to B17, comprising two or more conductors (204), wherein at least one conductor (204) is wrapped by a water shielding sheath (203).

[0124] Item B19. A plurality of power cables (202), each power cable (202) comprising a continuous metallic water-blocking sheath (203) enclosing at least one conductor (204), the water-blocking sheaths (203) of the individual power cables (202) being sealed and terminated at separate flanges (201’) of the housing (201), and at least one conductor 204 of a given power cable (202) extending through the respective flange (201’) into the interior (205) of the housing (201), the assembly according to any one of Items B1 to B18.

[0125] As will be appreciated, many other configurations of the ocean power system are possible, for example having floating wind turbines of different designs, other types of power generation facilities, different numbers of power generation facilities (from one to many), etc. However, for the purposes of this description, it is assumed that the power generation facility is a floating wind energy power generation facility.

[0126] FIG. 18 shows a floating wind energy power generation facility 7a comprising an array cable 1 for distributing power and / or control signals to or from the power generation facility 7a. As shown in FIG. 18, the array cable 1 is connected to the floater of the power generation facility 7a (here fixed to the column 15) and extends from the power generation facility 7a to the seabed and further to a connection point in the sea (for example, a junction box 3) or, for example, to land. The power generation facility 7a extends from the floater 10 and is moored to the seabed 4 by three mooring lines 30a - c fixed to the seabed 4 by anchors 31a - c. More than three mooring lines, for example four, five, six or more mooring lines may be used.

[0127] The array cable 1 has a slack 1' (e.g., on the order of dozens of meters or more). The slack 1' is thus part of the array cable 1 but is an unnecessary length at the normal operating position of the power generation facility 7a. The slack 1' may, for example, simply be placed on the seabed 4, but the slack 1' may also be arranged together with buoyancy elements or arranged in another suitable manner and fixed to the floater of the power generation facility 7a (e.g., suspended from the floater 10).

[0128] The slack 1' of the array cable 1 is operable and / or utilized during the breakage of any one of the single mooring cables 30a - 30c of the floating wind energy power generation facility 7a. When the mooring cables 30a - 30c are damaged and as a result the floating wind energy power generation facility 7a is displaced horizontally, the slack 1' of the array cable 1 prevents damage to the array cable 1 and / or an involuntary emergency detachment of the floating wind energy power generation facility 7a from the array cable 1.

[0129] In some embodiments, the slack 1' of the array cable 1 may, for example, be wound around the base of the floater 10. Alternatively, the slack 1' of the array cable 1 may preferably be positioned without being wound around the base of the floater 10 and may, for example, be suspended from the floater 10.

[0130] FIG. 19 illustrates the breakage of the mooring cable 30a of the floating wind power generation facility 7a according to the embodiment. As shown in FIG. 19, when the floating wind power generation facility 7a is operating, the mooring cable 30 may be damaged. In such a case, the slack 1' of the array cable 1 enables the floating wind power generation facility 7a to maintain its connection with the array cable 1 even when the floater 10 is displaced horizontally. The position of the floating wind power generation facility 7a may gradually move as shown in FIGS. 19 and 20 due to the breakage of the mooring cable 30a. As can be confirmed from FIG. 20, at several points, the remaining intact mooring cables 30b, c hold the floater 10 at a suitable location at a position different from the original position, that is, they prevent the further displacement of the floater 10. The length of the slack 1' can be selected to correspond to such a displacement distance when one mooring cable is damaged.

[0131] Due to the slack 1' of the array cable 1, the floating wind power generation facility 7a maintains its connection with the array cable 1 and thereby with the power grid. When the floater is displaced, the slack 1' is extended, fed out, or the like to correct the displacement without stretching or moving the remainder of the array cable 1 (i.e., the portion that extends further, for example, towards the junction box 3). Otherwise, such a break in the mooring cable 30a may lead to a break in the array cable 1. Therefore, the slack 1' of the array cable 1 enables the floating wind power generation facility 7a to maintain its connection with the array cable 1 during the breakage of any of the mooring cables 30a - 30c.

[0132] In the embodiment, the slack of the array cable 1 is a function of the lengths of the mooring cables 30a - 30c. For example, the slack 1' of the array cable 1 may be equal to the horizontal span of any of the mooring cables 30a - 30c.

[0133] In another embodiment, the slack 1' of the array cable 1 may exceed the horizontal span of any of the mooring cables 30a to 30c. Therefore, the slack 1' of the array cable 1 can be selected according to the requirements and design specifications of the floating wind energy power generation facility 7a.

[0134] Figure 21 shows the displacement of the floating wind energy power generation facility 7a as viewed from above. Both the respective positions of the floating wind energy power generation facility 7a from FIGS. 18 (illustrated by a solid line in FIG. 21) and 20 (illustrated by a dashed line in FIG. 21) are shown. In the case where the mooring cable 30a is damaged, the floating wind energy power generation facility 7a can move to any position restricted by the still intact mooring cables 30b to 30c. The farthest possible position from the initial position is shown by a dashed line in FIG. 21 and is equivalent to the situation shown in FIG. 20. The farthest movement distance s, which can also be selected as the minimum slack 1' of the array cable 1, can be geometrically calculated and is equal to the horizontal span of the mooring cable, which will be discussed in relation to the following figures. Also, the junction box 3 from FIG. 2 having the array cable 1 connected to the floating wind energy power generation facility 7a is schematically shown. When the mooring cable 30a is damaged and the position of the floating wind energy power generation facility 7a moves, the slack 1' of the array cable 1 extends, enabling the connection to the junction box 3 to remain undamaged without stress being applied to the array cable 1 due to the horizontal movement of the floating wind energy power generation facility 7a.

[0135] Figure 22 shows the calculations that can be used for the slack 1' of the array cable 1. In shallow sea locations or when using long mooring cables, the water depth d may be negligible compared to the length m of the mooring cable (m >> d). The horizontal span s of the mooring cable is, in that case, approximately equal to the length of the mooring cable (s ≒ m). In deeper sea locations or when using short mooring cables, the horizontal span can be calculated using the Pythagorean theorem s = sqrt(m 2 - d 2 ).

[0136] Figure 23 shows calculations that can be used for the slack 1' of the array cable 1 for any geometric arrangement of the mooring cables. The floating wind energy power plant 7a requires at least two intact mooring cables to prevent / minimize the risk of all mooring cables breaking. The furthest possible position from the initial position depends on the minimum angle β between any two adjacent mooring cables. The angle β is shown in Figure 23 for an embodiment of the floating wind energy power plant 7a having three mooring cables. In Figure 24, an embodiment of the floating wind energy power plant 7a having four mooring cables is shown, and the minimum angle β between any two adjacent mooring cables is indicated. The angle β can also be calculated for any arrangement (number and configuration) of the mooring cables.

[0137] The above system and method use the slack 1' of the array cable 1 to facilitate power generation in the floating wind energy power plant 7a. High reliability can be obtained, the risk of damage to costly cables can be reduced, and the need for an emergency release device in the power plant 7a can be alleviated or eliminated.

[0138] Various further aspects and examples of the present invention according to the present disclosure can be summarized in the following items.

[0139] Item C1. A method of operating a floating power plant (7a), comprising: mooring the power plant (7a) to the seabed (4) with a plurality of mooring cables (30a - c) fixed to anchors (31a - c) on the seabed (4); connecting at least one subsea cable (1), each having a slack (1'), to the floating power plant (7a); operating the power plant (7a) while temporarily stowing the slack (1') at or adjacent to the power plant (7a); and including. The slack (1’) of the subsea cable is configured to correct the horizontal displacement of the power generation facility (7a) in association with the remaining portion of the subsea cable (1), whereby, during breakage of any one of the plurality of mooring cables (30a to 30c), the remaining portion remains stationary and the subsea cable (1) remains operational.

[0140] Item C2. The method according to Item C1, wherein the length of the slack (1’) is a function of the length of one or more mooring cables (30a to 30c).

[0141] Item C3. The method according to Item C1 or C2, wherein the slack (1’) of the subsea cable (1) is supported by the floater (10) of the power generation facility (7a).

[0142] Item C4. The method according to any one of Items C1 to C3, wherein the slack (1’) is disposed on the seabed (4).

[0143] Item C5. The method according to any one of Items C1 to C4, wherein the slack (1’) is equal to or longer than the length of one or more mooring cables (30a to 30c).

[0144] Item C6. The method according to any one of Items C1 to C5, wherein the length (s) of the slack (1’) is equal to or longer than the function s = sqrt(m 2 - d 2 )(wherein m is the length of the mooring cable and d is the water depth).

[0145] Item C7. The method according to any one of Items C1 to C6, wherein the length (s) of the slack (1’) is equal to or longer than the function s = cos(β / 2) × 2 × m (wherein m is the length of the mooring cable and β is the minimum angle between two adjacent mooring cables).

[0146] Item C8. The length (s) of the slack (1’) is equal to or longer than the function s = cos(β / 2) × 2 × sqrt(m 2 - d 2(where m is the length of the mooring cable, d is the water depth, and β is the minimum angle between two adjacent mooring cables), the method according to any one of items C1 to C7, which is equal to or longer than that.

[0147] Item C9. A floating power generation facility (7a), comprising: a floater (10); mooring cables (30a to 30c) extending from the floater (10) to anchors (31a to 31c) on the seabed (4); a subsea cable (1) having a slack length (1') and connected to the power generation facility (7a); and wherein the slack length (1') of the subsea cable (1) is laid at or adjacent to the power generation facility (7a) and is configured to correct the horizontal displacement of the power generation facility (7a) in association with the remaining portion of the subsea cable (1), whereby, during the breakage of any one of the plurality of mooring cables (30a to 30c), the remaining portion remains stationary and the subsea cable (1) remains operational. A floating power generation facility.

[0148] Item C10. The floating power generation facility (7a) according to item C9, wherein the length of the slack length (1') is a function of the length of one or more mooring cables (30a to 30c).

[0149] Item C11. The floating power generation facility (7a) according to item C9 or C10, wherein the slack length (1') of the subsea cable (1) is supported by the floater (10) of the power generation facility (7a).

[0150] Item C12. The floating power generation facility (7a) according to any one of items C9 to C11, wherein the slack length (1') is disposed on the seabed (4).

[0151] Item C13. The floating power generation facility (7a) according to any one of items C9 to C12, wherein the slack length (1') is equal to or longer than the length of one or more mooring cables (30a to 30c).

[0152] Item C14. The length (s) of the slack length (1') is a function s = sqrt(m 2 - d 2(where m is the length of the mooring cable and d is the water depth), the floating power generation facility (7a) according to any one of items C9 to C13, which is equal to or longer than this.

[0153] Item C15. The length (s) of the slack (1’) is equal to or longer than the function s = cos(β / 2) × 2 × m (where m is the length of the mooring cable and β is the minimum angle between two adjacent mooring cables), the floating power generation facility (7a) according to any one of items C9 to C14.

[0154] Item C16. The length (s) of the slack (1’) is equal to or longer than the function s = cos(β / 2) × 2 × sqrt(m 2 -d 2 (where m is the length of the mooring cable, d is the water depth, and β is the minimum angle between two adjacent mooring cables), the floating power generation facility (7a) according to any one of items C9 to C15.

[0155] Referring to the previous examples in FIGS. 8 to 10 and additionally FIG. 25, FIGS. 8 and 9 illustrate an example of the junction box 3. As previously shown, as illustrated in FIG. 8, the junction box 3 can include wiring of one or more lengths that can function as internal connectors / connections and also fuses. As can be confirmed in FIGS. 9 and 25, the junction box of FIG. 3 can be recovered from the ship to the sea surface.

[0156] In the example of FIG. 25, one of the cables 20, 22 attached thereto can be or can include an input-side array cable from the array of marine power generation units (best illustrated in FIG. 2). Another one of the cables 20, 22 attached thereto can be or can include an output-side array cable that can extend to an onshore location.

[0157] To connect the input side array cable and the output side array cable, the junction box 3, as well as the input side and / or output side array cables, can be held on the ship. A person skilled in the art will understand that there can be various possible means, such as holding them by a crane or by a tensioner, for holding the junction box 3 and for the input side and / or output side array cables to be in a suitable position. The method can thus include the step of holding the junction box 3 on the ship. The method can further include the step of holding the input side / output side array cable on the ship.

[0158] Once the junction box 3 and the input side / output side array cables are held in a suitable position, the work is carried out at the junction box 3. The method described can thus include the step of carrying out work at the junction box 3, and optionally, the step of carrying out work at the junction box 3 while holding the junction box 3 and / or the input side and output side array cables on the ship. The work can enable the connection of the input side array cable to the inlet connection point and the output side array cable to the outlet connection point. The work can include the twisting of the input side / output side array cables. For example, the twisting can be with respect to a certain length of wiring inside the junction box 3. That certain length of wiring can provide an electrical connection between the inlet connection point and the outlet connection point. In that way, the twisting of the input side array cable to the inlet connection point and the outlet array cable to the outlet connection point can enable an electrical connection between the input side array cable and the output side array cable.

[0159] As illustrated in FIGS. 8 and 25, the junction box 3 in this example includes a housing. To facilitate the operations to be performed, the housing may include at least one access point. The access point may be in the form of at least one port through which the input-side array cable and the output-side array cable can be inserted or arranged. Alternatively, the access point may be in the form of a removable panel or hatch that can be opened or removed, thereby enabling access to the interior of the housing. Such access may assist in operations performed on the wiring inside the housing (e.g., twisting operations). For example, the top or side panel of the housing may be removable to facilitate operations performed on the wiring.

[0160] The access point may include a sealing portion or a sealing device. The sealing device may include at least one (e.g., a plurality of) individual sealing portions. When the junction box 3 is submerged in water (e.g., when it is positioned at a location in the sea), the sealing device can assist in preventing the ingress of water into the housing or at least into a portion of the housing where water ingress is undesirable, such as into a portion of the housing that includes or houses electrical connections. The sealing device may include at least one sealing portion disposed around the access point.

[0161] In the example illustrated, the housing is provided with a plurality of openings 26 thereon. In this example, the openings are in an aligned form. The alignment of the openings may enable the flooding of the housing of the junction box. Such flooding may enable easier handling of the junction box 3, for example, by reducing the buoyancy of the junction box 3 when it is disposed in the sea.

[0162] The junction box may include a portion of a material for holding the wiring disposed therein. For example, the junction box may include a portion of a material for holding the wiring inside the housing in a systematic manner. The portion of the material may be a length of flexible nose. The wiring may be wound around the flexible nose prior to working on the wiring and / or the input / output side array cables. The portion of the material may be removed from the junction box 3 in order to perform work on the wiring. Having a portion of the material for winding the wiring can facilitate the work performed on the wiring because it can enable the portions of the wiring to be conveniently arranged for twisting. For example, such a portion of the material can enable the portions of the wiring to be arranged near the access points.

[0163] The method may include performing a twisting operation on a ship on which the junction box 3 is held such that the input and output side array cables are twisted together with the internal cables in the junction box 3. The method may include continuously twisting the input and output side array cables to the internal cables in the junction box 3. For example, the method may include first twisting the input side array cable to the wiring in the junction box 3 and then twisting the output side array cable to the wiring in the junction box 3, or vice versa. Alternatively, the method may include directly twisting at least one component of the input side array cable to the output side array cable in the junction box 3. In that way, the method may include forming an electrical connection between the input and output side array cables. The method may include removing the input and output side array cables from the ocean power generation unit, and in that way, enable bypassing of the removed ocean power generation unit such that the rest of the array can still function. On the other hand, the removed ocean power generation unit can be lifted (e.g., lifted to an onshore location) for repair or replacement.

[0164] The method may include the step of placing the junction box 3 at a position in the sea after the operation is performed at the junction box 3. For example, the method may include the step of releasing the junction box 3 from a floating structure (e.g., a ship) and the step of placing the junction box 3 at a position in the sea. In one example, the method may include the step of releasing the junction box 3 from a ship and the step of placing the junction box on the seabed. Such placement of the junction box 3 may be accomplished by support means. The support means may be, or may include, a crane, a tensioner, etc. The support means may be used to lower the junction box 3 from a floating structure (e.g., a ship) to a position in the sea. As a result, the junction box 3 may be secured at a position in the sea. For example, the method may include the step of providing a subsea structure at which the junction box 3 is placed. The subsea structure may be, for example, a concrete mattress, a frame, etc. The subsea structure may assist in securing the junction box 3 to the seabed while still allowing the junction box 3 to be recovered if necessary. For example, the subsea structure may assist in preventing the settlement of the junction box 3 into sand or debris at the position in the sea, which may increase the difficulty associated with the recovery of the junction box 3 from the position in the sea.

[0165] When the junction box 3 is placed on a structure or on the seabed, the ship may stay there for a period (e.g., several days, weeks, or months) until the repair or replacement of the ocean power generation unit is completed. When the repair or replacement of the ocean power generation unit is completed, the junction box 3 can be lifted again onto a floating structure (e.g., a ship). On the floating structure, the input and output side array cables of the junction box can be removed therefrom and reattached to the repaired / replacement ocean power generation unit. In this way, the junction box 3 can facilitate the continuous functioning of the ocean power generation unit array while one of the ocean power generation units in the array is being replaced or repaired.

[0166] In FIG. 26, a ship 30 is illustrated at an offshore location where a plurality of power generation units, which in this case are wind turbines, are arranged. As illustrated, the wind turbine 20 has been removed from the array cable 1, where the array cable 1 terminates at the junction box 3. The junction box 3 is suspended from the ship 30 by a cable 32, and the junction box 3 supports the weight of the array cable 1 since it is itself supported from the ship 30 by the cable 32. In this case, the junction box 3 can be lowered to the seabed surface, and the ship 30 can be used to tow the wind turbine 20 to a position where the wind turbine 20 can be repaired. Meanwhile, the rest of the power generation units may be able to continue generating power with minimal interruption. When the wind turbine 20 is repaired, the ship 30 can lift the junction box 3 again and be used to reattach the repaired wind turbine 20 thereto. In this way, the use of the junction box 3 can improve the function by enabling the array of power generation units to supply power with minimal interruption caused by repair and maintenance, since the array cable termination can be safely placed in a position in the sea, for example, without the need for the ship 30 to stay on site while repair and / or maintenance work is being carried out.

[0167] Various further aspects and examples of the present invention according to the present disclosure may be summarized in the following items.

[0168] Item D1. The steps of removing the input - side and output - side array cables from the marine power generation unit (7), providing a junction box (3) having an inlet connection point and an outlet connection point, connecting the input - side cable to the inlet connection point and the output - side cable to the outlet connection point, positioning the junction box (3) at a position in the sea, using support means to position the junction box at a sub - surface position with the input - side array cable attached to the input - side connection point and the output - side cable attached to the output - side connection point, removing the input - side and output - side array cables from the inlet and outlet connection points respectively and reconnecting the input - side and output - side array cables to the marine power generation unit (7a), A method for temporarily removing a marine power generation unit (7) from an array of connected marine power generation units (7) including the above steps.

[0169] Item D2. The method according to Item D1, including the step of using support means to lower the junction box (3) from a sea - surface position to a sub - surface position.

[0170] Item D3. The method according to Item D1 or D2, including the step of using support means to lift the junction box (3) from a sub - surface position to a sea - surface position.

[0171] Item D4. The method according to any one of Items D1 to D3, including the step of using support means to lift the junction box (3) from a sub - surface position onto a floating structure.

[0172] Item D5. The method according to Item D4, wherein the floating structure (37) is a ship.

[0173] The method according to any one of items D1 to D5, including the step of performing operations with a junction box (3) to connect the input-side cable to the inlet connection point and the output-side cable to the outlet connection point.

[0174] The method according to item D6, wherein the operation is a twisting operation.

[0175] The method according to any one of items D1 to D7, including the step of installing a subsea structure where the junction box (3) is arranged at a subsea location.

[0176] The method according to item D8, wherein the subsea structure is a concrete mattress.

[0177] The method according to any one of items D1 to D9, wherein the junction box (3) comprises a housing including an inlet access part for providing access to the inlet connection point and an outlet access part for providing access to the outlet connection point, and the inlet access part and the outlet access part are separated and different from each other.

[0178] The method according to any one of items D1 to D10, wherein the input-side and output-side array cables are two separate cables.

[0179] The method according to any one of items D1 to D11, including the step of installing an anti-corrosion device on the junction box (3).

[0180] The method according to any one of items D1 to D12, wherein the marine power generation unit (7) is a floating wind turbine.

[0181] A housing having an inlet connection point and an outlet connection point, wherein the inlet connection point communicates with the outlet connection point via an internal cable arranged inside the housing, and comprising a lifting engagement device for connecting lifting means. The housing is provided with a lifting engagement device for connecting lifting means. A junction box (3) for temporary connection to an array of marine power generation units (7), having inlet and outlet cables at the inlet and outlet connection points and being capable of being lifted via engagement of a lifting means with a lifting engagement part.

[0182] The present invention is not limited by the above embodiments, refer to the appended claims.

Claims

1. a plurality of first cables (1a-n), each first cable (1a-n) having a first dry-mating connection (2b) at a first end (9b) thereof and connected at a second end (9a) thereof to a marine generator unit (7); a subsea junction box (3) disposed on the seabed (4), each dry-coupled connection (2b) terminating inside said junction box (3); a second cable (5) extending from the junction box (3) to a subsea substation (6) disposed on the seabed (4), the second cable (5) having a second dry-coupled connection (10a) at an end (11a) thereof, the second dry-coupled connection (10a) terminating inside the junction box (3) operatively connected to the first dry-coupled connection (2b); a second cable (5) extending to a subsea substation (6) disposed on the seabed (4) and operably connected to the substation (6); a third cable (12) extending from the substation (6) to a land-based receiver (8); Equipped with configured to transmit power from the marine generator unit (7) to an onshore power receiver (8) via the first, second and third cables; A marine power distribution system (100), wherein the subsea junction box is open to the environment.

2. The first dry-coupled connection (2b) A dry-mating connector (2b), or Twisted joint 2. The marine power distribution system (100) of claim 1 .

3. The second dry-coupled connection (10a) A dry-mating connector (10a), or Twisted joint 3. The marine power distribution system (100) of claim 1 or 2,

4. 4. The marine power distribution system (100) of claim 1, wherein the third cable (12) is configured to operate at a higher voltage than the first cable (1a-n) and the second cable (5).

5. The marine power distribution system (100) of any one of claims 1 to 4, wherein the first cable (1a-n) and the second cable (5) are configured to operate at the same voltage.

6. 6. The marine power distribution system (100) of claim 1, wherein the cross-section of the third cable (12) is smaller than the cross-section of the second cable (5) or the combined cross-section of a plurality of second cables (5).

7. The marine power distribution system (100) of any one of claims 1 to 6, wherein the subsea junction box (3) is recoverable to the sea surface.

8. 8. The marine power distribution system (100) of claim 1, wherein each of the plurality of first cables (1a-n) is operatively connected to an in-line fuse (33) disposed in the junction box (3).

9. The marine power distribution system (100) of any one of claims 1 to 8, wherein the plurality of first cables (1a-n) have a design operating voltage of greater than 40 kV.

10. 10. The marine power distribution system (100) of any one of claims 1 to 9, wherein each generating unit (7) comprises a respective power switch disposed on or within the generating unit (7), the power switch being operable to selectively disconnect the respective generating unit (7) from its first cable (1a-n).

11. 11. The marine power distribution system (100) of claim 10, wherein none of the first cable (1a-n), the subsea junction box (3), the second cable (5), and the substation (6) includes a power switch operable to selectively disconnect a generating unit (7).

12. 12. The marine power distribution system (100) of any one of claims 1 to 11, wherein an end (35) of the first cable (1a-n) and an end (36) of the second cable (5) are arranged in parallel on the seabed (4).

13. 13. The marine power distribution system (100) of claim 12, wherein the terminal end (35) of the first cable (1a-n) and the terminal end (36) of the second cable (5) are arranged at a position having a water depth, and the terminal end (35) of the first cable (1a-n) and the terminal end (36) of the second cable (5) arranged in parallel on the seabed (4) each have a length that exceeds the water depth.

14. The marine power distribution system (100) of any one of claims 1 to 13, wherein the subsea junction box does not include wet mate connectors.

15. The marine power distribution system (100) of claim 1, wherein the subsea junction box is a frame-type box.

16. installing a plurality of generators (7), each generator having a first cable (1a-n) having a first dry mating connector (2b) at a first end (9b) of said first cable; installing a subsea substation (6) on the seabed (4) and installing a third cable (12) extending from the substation (6) to an onshore receiver (8); installing a subsea junction box (3) on the seabed (4); connecting the subsea junction box (3) and the substation (6) with a second cable (5); connecting said first cable (1a-n) with said second cable (5), comprising establishing a dry-coupled connection between said first cable (1a-n) and said second cable (5) in said junction box (3); Including, A method of installing a marine power distribution system (100), wherein the subsea junction box is open to the environment.

17. placing the first dry mate connector (2b) underwater on the seabed (4); 17. The method according to claim 16, wherein the step of connecting the first cable (1a-n) with the second cable (5) comprises retrieving the first dry-mating connector (2b) from the seabed (4) and establishing the dry-mating connection between the first cable (1a-n) and the second cable (5) on a vessel (20).

18. placing a second dry-mating connector (10a) underwater on the seabed (4) for connection to the second cable (5); The method according to claim 16 or 17, wherein the step of connecting the first cable (1a-n) with the second cable (5) comprises retrieving the second dry-couple connector (10a) from the seabed (4) and thereafter establishing the dry-couple connection between the first cable (1a-n) and the second cable (5) on a vessel (20).

19. 19. The method according to any one of claims 16 to 18, comprising the step of laying an end (35) of the first cable (1a-n) and an end (36) of the second cable (5) in parallel on the seabed (4).

20. 20. The method according to claim 19, wherein the terminal end (35) of the first cable (1a-n) and the terminal end (36) of the second cable (5) are disposed at a position having a water depth, and the terminal end (35) of the first cable (1a-n) and the terminal end (36) of the second cable (5), which are disposed in parallel on the seabed (4), each have a length that exceeds the water depth.

21. 21. The method according to any one of claims 16 to 20, comprising the step of installing the subsea substation (6) together with the second cable (5) with a transformer end connector (10b) of the second cable (5) pre-installed in the substation (6).

22. 22. The method according to any one of claims 16 to 21, comprising the step of installing the subsea substation (6) together with the third cable (12) or the portion of the third cable (12), with the third cable (12) or the portion of the third cable (12) being pre-installed in the substation (6).

23. 23. The method of any one of claims 16 to 22, wherein the subsea junction box does not include wet mate connectors.

24. The method of claim 16 , wherein the subsea junction box is a frame-type box.

25. Operating a system according to any one of claims 1 to 15; Retrieving the junction box (3) from the seabed (4) to a vessel (20); carrying out work on said junction box (3); reinstalling said junction box (3) on said seabed (4); A method for distributing power in a marine power distribution system (100), comprising:

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