Offshore substation

Abstract

To provide an offshore substation that makes effective use of limited space. [Solution] An offshore substation 1 is installed offshore and has multiple floors, and is connected to multiple offshore wind turbines 100 by transmission cables 110. Each of the multiple offshore substations is connected to three offshore wind turbines by transmission cables. In this configuration, electricity generated by multiple offshore wind turbines is collected at the offshore substations, which act as relay points, and the voltage and current flowing through the transmission cables are adjusted before the electricity is sent to onshore power receiving equipment. This reduces power loss during transmission and also reduces the cost of the transmission cables 110 from the offshore substations to the onshore power receiving equipment.

Description

Technical Field

[0001] This disclosure relates to an offshore substation.

Background Art

[0002] Conventionally, an offshore substation has been installed offshore.

[0003] Patent Document 1 discloses an offshore substation.

[0004] Patent Document 2 discloses a connection station including a transformer.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0006] However, since an offshore substation is installed offshore, the available space is limited. There was room for improvement in effectively utilizing the limited space in the offshore substation of Patent Document 1 and the connection station of Patent Document 2.

[0007] This disclosure has been made in view of such problems, and an object thereof is to provide a technology capable of effectively utilizing limited space in an offshore substation.

Means for Solving the Problems

[0008] An offshore substation according to an aspect of this disclosure is an offshore substation installed offshore and includes a plurality of floors.

Effects of the Invention

[0009] This disclosure provides a technology that enables effective use of limited space in offshore substations. [Brief explanation of the drawing]

[0010] [Figure 1] This diagram shows the relative positions of offshore wind turbines and offshore substations. [Figure 2] This is a front view of a first example of an offshore substation according to this embodiment. [Figure 3] This is a front view of a second example of an offshore substation according to this embodiment. [Figure 4] This is a front view of a third example of an offshore substation according to this embodiment. [Figure 5] This is a cross-sectional view showing the internal structure of a building in an offshore substation according to this embodiment, and is a diagram showing an example of the first arrangement of each piece of equipment. [Figure 6] This is a cross-sectional view showing the internal structure of a building in an offshore substation according to this embodiment, and is a diagram showing an example of a second arrangement of each piece of equipment. [Figure 7] This is a cross-sectional view showing the internal structure of a building in an offshore substation according to this embodiment, and is a diagram showing an example of a third arrangement of each piece of equipment. [Modes for carrying out the invention]

[0011] Hereinafter, an offshore substation 1 according to one embodiment of this disclosure will be described with reference to the drawings.

[0012] Wind power generation is a method of generating electricity using wind energy, and it is being increasingly put into practical use as a power generation method that is inexhaustible and has a low environmental impact. In particular, offshore wind power generation uses winds blowing over the ocean to rotate wind turbines installed in the sea (offshore wind turbines) and generate electricity. Therefore, compared to land, there are fewer obstacles, resulting in better wind conditions, and it is possible to make larger facilities, which has advantages such as cost reduction.

[0013] On the other hand, when installing wind turbines offshore, the long distance from the offshore turbine to the onshore power receiving equipment presents various challenges in transmitting power from the turbine to the equipment. For example, transmitting power over long distances using transmission cables connecting the offshore turbine and the onshore power receiving equipment can lead to power loss. Also, for example, if the amount of power generated by the offshore wind turbine increases, it may exceed the capacity of the transmission cables used to transmit the electricity generated by the offshore wind turbine to the outside. In response to this, transmission cables with a large capacity (high tolerance) are proportionally thicker and more expensive, so installation can be costly, especially when the distance from the offshore turbine to the land is long.

[0014] The offshore substation 1 of this disclosure is used, for example, as a substation in offshore power generation as described above. The offshore substation 1 according to this embodiment may be provided as a single unit or in multiple units in the same sea area or wind farm. If multiple offshore substations 1 are provided, for example, adjacent offshore substations 1 may be connected by a transmission cable 110 to exchange electricity generated by each other.

[0015] Figure 1 shows an example of the arrangement between the offshore wind turbine 100 and the offshore substation 1. A single offshore substation 1 may be connected to multiple offshore wind turbines 100 by transmission cables 110. In the example shown in Figure 1, the offshore substation 1 is connected to three offshore wind turbines 100 by transmission cables 110. With this configuration, the electricity generated by multiple offshore wind turbines 100 can be aggregated at the offshore substation 1, which acts as a relay point. As will be described in detail later, this allows the offshore substation 1 to adjust the voltage and current flowing through the transmission cables 110 before sending the electricity to the onshore receiving equipment. Therefore, power loss during transmission can be suppressed, and the cost of the transmission cables 110 from the offshore substation 1 to the onshore receiving equipment can be reduced.

[0016] The offshore substation 1 of this embodiment includes a plurality of floors 20, a substructure 30, a storage battery 41, a transformer 43, a rectifier 42, and a switchgear 44. In this embodiment, the floor 20 indicates the floor in the building 10.

[0017] The substructure 30 is a structure that supports the offshore substation 1. For the substructure 30, for example, a known configuration is preferably used. The substructure 30 may preferably be any one of a jacket foundation as shown in FIG. 2, a monopile foundation as shown in FIG. 3, and a floating foundation as shown in FIG. 4. The monopile foundation shown in FIG. 3 is composed of a monopile 30M driven into the seabed. The floating foundation shown in FIG. 4 is configured by supporting a floating body 30F floating on the sea by a wire 30W connected to the seabed. The building 10 in the floating foundation shown in FIG. 4 is supported on the sea by the buoyancy acting on the floating body 30F. In this embodiment, the substructure 30 is a jacket foundation as shown in FIG. 2. That is, the substructure 30 at least includes a leg 32 to which the lower end of the building 10 is connected and which supports the building 10. As shown in FIG. 2, the substructure 30 is arranged offshore by connecting the leg 32 to a pile P driven into the seabed.

[0018] The floor 20, for example, indicates a floor. The building 10 of the offshore substation 1 of this embodiment is provided with three floors 20, namely, a first floor 21 (the first floor), a second floor 22 (the second floor), and a third floor 23 (the third floor). The number of floors 20 of the offshore substation 1 is not limited to three, and may be, for example, two, or may be, for example, four or more.

[0019] In this embodiment, the multiple floors 20 are surrounded by walls on all sides. The floors 20 may have multiple rooms, for example, with their interiors partitioned by walls. Furthermore, it is preferable that the multiple floors 20 are located above sea level. For the multiple floors 20 to be located above sea level means that the lower end of the building 10 having the multiple floors 20 is located above sea level. Some or all of the multiple floors 20 may be located below sea level. That is, for example, at least a portion of the first floor 21 to the third floor 23 may be located below sea level. For example, the first floor 21 and the second floor 22 may be located below sea level.

[0020] Various equipment, such as a storage battery 41, a transformer 43, and a rectifier 42, may be installed on the first floor 21 to the third floor 23 (details will be described later). For example, the transformer 43 is relatively large in scale, and its size may be larger than the floor height of the floor 20 of the offshore substation 1. In this case, the heights of the first floor 21, the second floor 22, and the third floor 23 may be set appropriately. In this case, the floor heights of each floor 20 may be uniform, or the floor heights of some or all of the floors 20 may be different.

[0021] Next, as shown in Figures 5 to 7, the various pieces of equipment (storage battery 41, rectifier 42, transformer 43, switchgear 44) of the offshore substation 1 of this embodiment will be described.

[0022] The battery 41 stores the electricity generated by the offshore wind turbine 100. In this case, the power generated by the offshore wind turbine 100 may change due to changes in wind strength at the installation site of the offshore wind turbine 100. When the power generated by the offshore wind turbine 100 increases, it may exceed the capacity of the transmission cable 110 that transmits the electricity generated by the offshore wind turbine 100 to the outside. In other words, the electricity generated by the offshore wind turbine 100 may cause a current exceeding the allowable range to be applied to the transmission cable 110. A portion of the electricity generated by the offshore wind turbine 100 is stored in the battery 41. The remaining electricity is then transmitted to the onshore power receiving equipment via the transmission cable 110. In this way, the current flowing through the transmission cable 110 is regulated. The electricity stored in the battery 41 is discharged when the power output of the offshore wind turbine decreases and the discharge does not exceed the allowable range of the transmission cable 110, and is then transmitted via the transmission cable 110. By transmitting the electricity generated by the offshore wind turbine 100 in this manner, it is possible to prevent the transmission cable 110 from receiving a current that exceeds its allowable range. The arrangement of the battery 41 at the offshore substation 1 will be described later. The transmission cable 110 may be arranged, for example, along the leg 32 of the substructure 30 (jacketed foundation) or on the seabed. If the substructure 30 is a floating foundation, the transmission cable 110 may be arranged, for example, on the seabed or in the sea.

[0023] The rectifier 42 converts the electricity transmitted by the cable 50 from alternating current (AC) to direct current (DC), or from direct current to AC. For example, when the electricity generated by the offshore wind turbine 100 is stored in the battery 41, the rectifier 42 converts the electricity from AC to DC. In other words, the battery 41 stores the electricity that has been converted to AC by the rectifier 42. For example, when the electricity stored in the battery 41 is discharged, the rectifier 42 converts the electricity from DC to AC. In other words, the rectifier 42 converts the electricity discharged from the battery 41 from DC to AC. That is, the electricity generated by the offshore wind turbine 100 is AC, and the electricity stored in the battery 41 is DC. The rectifier 42 includes, for example, a well-known PCS (Power Conditioning System). A system is preferably used. The arrangement of the rectifiers 42 in the offshore substation 1 will be described later.

[0024] The transformer 43 transforms the voltage of electricity. For example, the transformer 43 transforms the voltage of electricity generated by the offshore wind turbine 100, and the voltage of electricity discharged from the storage battery 41 and converted by the rectifier 42. In this embodiment, the voltage of the electricity generated by the offshore wind turbine 100 is higher than the voltage that the rectifier 42 can process. Therefore, the transformer 43 steps down the voltage to a level that the rectifier 42 can process when, for example, the electricity generated by the offshore wind turbine 100 is stored in the battery 41 via the rectifier 42. This prevents an excessive voltage from being applied to the rectifier 42. The transformer 43 may step up the voltage of the electricity discharged from the battery 41 and converted from DC to AC by the rectifier 42. This may improve the efficiency of power transmission within the offshore substation 1. Alternatively, the transformer 43 may step up the voltage of the electricity transmitted when the offshore wind turbine 100 is transmitted to the outside. This may improve the efficiency of power transmission from the offshore substation 1 to the onshore receiving equipment. The arrangement of the transformer 43 in the offshore substation 1 will be described later.

[0025] The switchgear 44 opens and closes electrical circuits to, for example, receive power generated by the offshore wind turbine 100, send the electricity to the transformer 43 to convert it to a usable voltage, and then transmit it to various parts of the facility, or transmit power generated by the offshore wind turbine 100 and power discharged from the storage battery 41 to onshore power receiving equipment. Since the switchgear 44 is used for turning electricity on and off and protecting equipment, it is placed, for example, before and after electrical equipment such as transformers, or at the source of power transmission cables. The arrangement of the switchgear 44 in offshore substation 1 will be described later.

[0026] Next, with reference to Figures 5 to 7, the arrangement of each of the above-mentioned facilities on multiple floors 20 will be described. Figures 5 to 7 are cross-sectional views showing the internal structure of the building 10 in the offshore substation 1, each showing a different example. The offshore substation 1 of this embodiment has three floors 20, from the first floor 21 to the third floor 23. Therefore, in the following description, we will describe the case where each piece of equipment is installed on any of the first floors 21 to the third floor 23, but the arrangement of each piece of equipment is not limited to the examples described later. For example, if the offshore substation 1 has only two floors 20, the first floor 21 and the second floor 22, each piece of equipment may be installed on either the first floor 21 or the second floor 22. For example, if the offshore substation 1 has four floors 20, from the first floor to the fourth floor, each piece of equipment may be installed on any of the first floor to the fourth floor. Also, there may be floors 20 on which no equipment is installed. Thus, since each piece of equipment can be placed on any of the multiple floors 20 of the offshore substation 1, the placement of each piece of equipment can be considered within a relatively large installation area. This allows for, for example, to optimize the placement of each piece of equipment. Here, optimizing the placement of each piece of equipment may mean, for example, placing the equipment in a way that considers the work efficiency of installation or maintenance workers, placing the equipment in a way that considers equipment costs such as the length of the cables 50, or placing the equipment in a way that considers the effects of waves, rain, wind, etc. on each piece of equipment.

[0027] Figure 5 shows an example of the first arrangement of each piece of equipment in offshore substation 1. In the first example of the arrangement, the battery 41 is installed on the third floor 23. In the illustrated example, three battery 41s are installed, but the number of battery 41s is not limited and may be one or more. It is preferable to install multiple battery 41s because it is possible to increase the capacity of electricity that can be stored in the offshore substation 1. In the first example of the arrangement, since the only equipment installed on the third floor 23 is the battery 41, it is easy to secure space for the battery 41. For this reason, multiple battery 41s can be easily installed on the third floor 23. In the first example of the arrangement, the rectifier 42 is installed on the second floor 22 (second floor), which is a different floor 20 from the third floor 23 where the battery 41 is installed. In the first example of the arrangement, the rectifier 42 is connected to the battery 41 via a cable 50. In the first example of the arrangement, the transformer 43 is installed on the first floor 21 (1st floor), which is a different floor 20 from the third floor 23 where the battery 41 is located. In the first example of the arrangement, the transformer 43 is connected to the rectifier 42 via a cable 50. In the first example of the configuration, the switchgear 44 is installed on the first floor 21 (1st floor), which is a different floor 20 from the third floor 23 where the battery 41 is located. In the first example of the configuration, the switchgear 44 is connected to the transformer 43 via a cable 50.

[0028] The switchgear 44 and transformer 43 are larger in scale and heavier in weight compared to equipment such as the battery 41. Therefore, from the viewpoint of lowering the center of gravity of the building 10, it is preferable to install relatively heavy equipment such as the switchgear 44 and transformer 43 on the first floor 21 (1st floor), for example.

[0029] In this first example of configuration, the flow of electricity when the offshore substation 1 receives power generated by the offshore wind turbine 100 will be described. In this first example of configuration, the electricity generated by the offshore wind turbine 100 is transmitted to the switchgear 44 via the transmission cable 110. The electricity transmitted to the switchgear 44 is transmitted to the transformer 43 via the cable 50. The transformer 43 steps down the electricity to a voltage that the rectifier 42 can process. The current, stepped down to a voltage that the rectifier 42 can process, is transmitted from the transformer 43 to the rectifier 42 via the cable 50. The rectifier 42 converts the electricity from alternating current to direct current. The electricity converted from alternating current to direct current is transmitted from the rectifier 42 to the battery 41 via the cable 50. This allows the electricity generated by the offshore wind turbine 100 to be stored in the battery 41. Furthermore, the electricity generated by the offshore wind turbine 100 does not necessarily have to be stored in the battery 41, and all of the electricity generated by the offshore wind turbine 100 may be transmitted to the onshore power receiving equipment without being stored. Specifically, for example, if the electricity generated by the offshore wind turbine 100 does not exceed the capacity of the transmission cable 110, the electricity generated by the offshore wind turbine 100 may be transmitted to the onshore power receiving equipment via the transmission cable 110 without being stored in the battery 41.

[0030] In the first example of the configuration, the flow of electricity when the electricity stored in the battery 41 is discharged will be described. In the first example of the configuration, the electricity discharged from the battery 41 is transmitted to the rectifier 42 via the cable 50. The rectifier 42 converts the electricity from direct current to alternating current. The electricity converted from direct current to alternating current is transmitted from the rectifier 42 to the transformer 43 via the cable 50. The transformer 43 may also step up the voltage of the electricity. The electricity that has passed through the transformer 43 is transmitted to the switchgear 44 via the cable 50. The switchgear 44 sends electricity to the transmission cable 110 which is connected from the offshore substation 1 to the onshore power receiving equipment, and transmits the electricity to the onshore power receiving equipment via the transmission cable 110.

[0031] Figure 6 shows an example of a second arrangement of equipment in offshore substation 1. In the second example of the arrangement, the battery 41 is installed on the third floor 23. In the illustrated example, one battery 41 is installed, but the number of batteries 41 is not limited and may be multiple. It is preferable to install multiple batteries 41 because it is possible to increase the capacity of electricity that can be stored in the offshore substation 1. In the second example of the arrangement, the rectifier 42 is installed on the same third floor 23 (3rd floor) as the battery 41. In the second example of the arrangement, the rectifier 42 is connected to the battery 41 via a cable 50. When the rectifier 42 is located on the same floor as the battery 41, for example, the cable 50 connecting the rectifier 42 and the battery 41 can be shortened. In the second example of the arrangement, the transformer 43 is installed on the first floor 21 (1st floor), which is a different floor 20 from the third floor 23 where the battery 41 is located. In this example, the transformer 43 is larger than the floor height of one floor 20, and therefore spans multiple floors 20. Specifically, in this example, the transformer 43 spans the first floor 21 and the second floor 22. In the first example of the arrangement, the transformer 43 is connected to the rectifier 42 via a cable 50. In the second example of the arrangement, the switchgear 44 is installed on the first floor 21 (1st floor), which is a different floor 20 from the third floor 23 where the battery 41 is located. In the first example of the arrangement, the switchgear 44 is connected to the transformer 43 via cable 50.

[0032] The flow of electricity when the offshore substation 1 receives power generated by the offshore wind turbine 100 in the second example of the configuration, and the flow of electricity when the battery 41 is discharged, are the same as in the first example of the configuration, so they will be omitted.

[0033] Figure 7 shows an example of a third arrangement of equipment in offshore substation 1. In the third example of the arrangement, the battery 41, transformer 43, rectifier 42, and switchgear 44 are all installed on the same second floor 22 (second floor). In the illustrated example, only one battery 41 is installed, but the number of batteries 41 is not limited and there may be multiple batteries. It is preferable to install multiple batteries 41 because it is possible to increase the capacity of electricity that can be stored in the offshore substation 1. If the transformer 43, switchgear 44, and rectifier 42 are installed on the same floor as the battery 41, for example, the cables 50 connecting each piece of equipment to the battery 41 can be shortened. In the third example of the arrangement, the battery 41 is connected to the rectifier 42 via cable 50, the rectifier 42 is connected to the transformer 43 via cable 50, and the transformer 43 is connected to the switchgear 44 via cable 50.

[0034] The flow of electricity when the offshore substation 1 receives power generated by the offshore wind turbine 100 in the third configuration example, and the flow of electricity when the battery 41 is discharged, are the same as in the first configuration example and are therefore omitted.

[0035] The arrangement is not limited to the above examples. For example, the battery 41 may be installed on the first floor 21. For example, the rectifier 42 may be installed on the first floor 21. For example, the transformer 43 may be installed on the third floor 23. For example, the switchgear 44 may be installed on the third floor 23. For example, the transformer 43 may be arranged across the first floor 21, the second floor 22, and the third floor 23.

[0036] As described above, the offshore substation 1 of this disclosure is an offshore substation 1 installed offshore, comprising a plurality of floors 20. With this configuration, various equipment for the offshore substation 1 can be installed on multiple floors 20. Because equipment can be installed on multiple floors 20, a larger area for equipment installation can be secured compared to, for example, a case where the offshore substation 1 has only one floor 20. Therefore, the limited space in the offshore substation 1 can be used effectively.

[0037] Furthermore, multiple floors 20 may be located above sea level. With this configuration, the effects of seawater can be suppressed on multiple floors 20. For example, when workers perform tasks on each of the multiple floors 20, the work sites will be less affected by seawater, ensuring safety at the work sites. In addition, the equipment installed in the offshore substation 1 is susceptible to deterioration and failure due to salt damage. With the above configuration, the exposure of each piece of equipment located on each of the multiple floors 20 to seawater can be suppressed, thereby suppressing deterioration and failure due to salt damage. As a result, workers can work more safely, and deterioration and failure of the equipment located on each of the multiple floors 20 can be suppressed.

[0038] Furthermore, a storage battery 41 may be provided. The amount of electricity generated by the offshore wind turbine 100 may change due to changes in wind strength at the installation site of the offshore wind turbine 100. In this case, if the amount of electricity generated by the offshore wind turbine 100 increases, it may exceed the capacity of the transmission cable 110 that transmits the electricity generated by the offshore wind turbine 100 to the outside. In other words, the electricity generated by the offshore wind turbine 100 may cause a current exceeding the allowable range to be applied to the transmission cable 110. Furthermore, a transmission cable 110 with a larger allowable range (high performance) is proportionally thicker and more expensive, making its installation difficult from a cost perspective. With the configuration described above, by installing a battery 41 at the offshore substation 1, when the power transmitted from multiple offshore wind turbines 100 is large, at least a portion of that power can be stored in the battery 41. This reduces the amount of power transmitted from the offshore substation 1 to land when the power generated by the offshore wind turbines 100 is large, and allows the power stored in the battery 41 to be transmitted to land when the power generated by the offshore wind turbines 100 is small. Therefore, the power transmitted from the offshore substation 1 to land can be leveled by using the power stored in the battery 41. Thus, the cost required for the transmission cable 110 for power transmission can be reduced.

[0039] Furthermore, the battery 41 may be installed on any of the multiple floors 20. With this configuration, the battery storage system 41 can be installed on any of the multiple floors 20, allowing for consideration of the battery storage system 41's placement within a relatively large installation area. This makes it easier to install the battery storage system 41 in the offshore substation 1. Furthermore, by considering the placement of the battery storage system 41 within a relatively large installation area, the battery storage system 41 can be arranged more efficiently. Thus, the limited space in the offshore substation 1 can be used effectively.

[0040] Furthermore, a rectifier 42 may be provided. By providing the rectifier 42, the alternating current power transmitted from the offshore wind turbine 100 can be converted to direct current and stored in the battery 41.

[0041] Furthermore, among the multiple floors 20, the floor 20 on which the rectifier 42 is installed and the floor 20 on which the storage battery 41 is installed may be the same. With this configuration, by installing the rectifier 42 and the battery 41 on the same floor 20, for example, the cable 50 connecting the rectifier 42 and the battery 41 can be shortened. Therefore, the limited space in the offshore substation 1 can be used effectively, and installation costs can be reduced.

[0042] Furthermore, among the multiple floors 20, the floor 20 on which the rectifier 42 is installed and the floor 20 on which the storage battery 41 is installed may be different. With this configuration, by installing the rectifier 42 and the battery 41 on different floors 20, for example, more space can be secured for the battery 41. This makes it easier to install more batteries 41 on the floor 20 where the batteries 41 are installed. Therefore, for example, by installing more batteries 41, the amount of electricity that can be stored in the offshore substation 1 can be increased.

[0043] Furthermore, a transformer 43 may be provided. With this configuration, by installing the transformer 43, the electricity transmitted from the offshore wind turbine 100 and the electricity discharged from the storage battery 41 can be transformed.

[0044] Furthermore, among the multiple floors 20, the floor 20 on which the transformer 43 is located may be the same as the floor 20 on which the storage battery 41 is located. With this configuration, by installing the transformer 43 and the battery 41 on the same floor 20, for example, the cable 50 connecting the transformer 43 and the battery 41 can be shortened. Therefore, the limited space in the offshore substation 1 can be used effectively, and installation costs can be reduced.

[0045] Furthermore, among the multiple floors 20, the floor 20 on which the transformer 43 is located may be different from the floor 20 on which the storage battery 41 is located. With this configuration, by installing the transformer 43 and the battery 41 on different floors 20, for example, more space can be secured for the battery 41. Therefore, for example, it becomes easier to install more battery 41s on the floor 20 where the battery 41 is installed. Thus, for example, by installing more battery 41s, the amount of electricity that can be stored at the offshore substation 1 can be increased.

[0046] The transformer 43 may be arranged across the multiple floors 20. The transformer 43 is relatively large in scale, and its size may be greater than the floor height of the floor 20 of the offshore substation 1. With the above configuration, since the transformer 43 is arranged across multiple floors 20, a large-scale transformer 43 can be easily installed regardless of the floor height of the floors 20 in the offshore substation 1.

[0047] Furthermore, a switchgear 44 may be provided. With this configuration, by installing a switchgear 44, the power received from the offshore wind turbine 100 can be converted to a usable voltage and sent to various locations.

[0048] Among the multiple floors 20, the floor 20 on which the switchgear 44 is located and the floor 20 on which the storage battery 41 is located may be the same. With this configuration, the switchgear 44 and the battery 41 can be installed on the same floor 20, thereby shortening the cable 50 connecting the switchgear 44 and the battery 41. This allows for effective use of the limited space in the offshore substation 1 and reduces installation costs.

[0049] Of the multiple floors 20, the floor 20 on which the switchgear 44 is located and the floor 20 on which the storage battery 41 is located may be different. With this configuration, by installing the switchgear 44 and the battery 41 on different floors 20, for example, more space can be secured for the battery 41. This makes it easier to install more batteries 41 on the floor 20 where the batteries 41 are installed. Therefore, for example, by installing more batteries 41, the amount of electricity that can be stored in the offshore substation 1 can be increased.

[0050] Furthermore, it is possible to replace the components in the above embodiments with well-known components as appropriate, without departing from the spirit of this disclosure, and the above-described modifications may be combined as appropriate.

[0051] For example, floor 20 does not need to be covered by walls on its entire perimeter. Specifically, for example, if sufficient measures are taken to protect the equipment installed on floor 20 from salt damage, floor 20 on which the equipment is installed does not need to be covered by walls, and walls may be provided only on a part of it. [Explanation of Symbols]

[0052] 1. Offshore substation 10 buildings 20 floors 21 1st Floor 22 2nd Floor 23 Third Floor 30 Undercarriage 32 Legs 30M Monopile 30F Floating Body 30W Wire 41 Storage Battery 42 Rectifier 43 Transformer 44 Switchgear 50 Cables 100 offshore wind turbines 110 Transmission Cable P pile

Claims

1. An offshore substation installed on the sea, Multiple floors, An offshore substation equipped with the necessary equipment.

2. The aforementioned multiple floors are located above sea level. The offshore substation according to feature 1.

3. Storage batteries, The offshore substation according to claim 2, further comprising the above.

4. The storage battery is installed on one of the multiple floors. The offshore substation according to feature 3.

5. rectifier, The offshore substation according to claim 3 or 4, further comprising the above.

6. The rectifier converts the power transmitted from the offshore wind turbine from alternating current to direct current. The offshore substation according to feature 5.

7. Of the aforementioned multiple floors, the floor on which the rectifier is installed and the floor on which the storage battery is installed are the same. The offshore substation according to feature 6.

8. Of the aforementioned multiple floors, the floor on which the rectifier is installed and the floor on which the storage battery is installed are different. The offshore substation according to feature 6.

9. Transformer, An offshore substation according to claim 3 or 4, further comprising the above.

10. The transformer transforms the electricity transmitted from the offshore wind turbine and the electricity discharged by the battery. The offshore substation according to feature 9.

11. Of the aforementioned multiple floors, the floor on which the transformer is located is the same as the floor on which the storage battery is located. The offshore substation according to feature 9.

12. Of the aforementioned multiple floors, the floor on which the transformer is located is different from the floor on which the storage battery is located. The offshore substation according to feature 9.

13. The transformer is arranged across the multiple floors, The offshore substation according to feature 9.

14. Switchgear, The offshore substation according to claim 3 or 4, further comprising the above.

15. Of the aforementioned multiple floors, the floor on which the switchgear is located and the floor on which the storage battery is located are the same. The offshore substation according to feature 14.

16. Of the aforementioned multiple floors, the floor on which the switchgear is located and the floor on which the storage battery is located are different. The offshore substation according to feature 14.

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