Improvements relating to offshore converter platforms in power transfer networks

Abstract

The name of the invention is' Improvements relating to offshore converter platforms in power transfer networks'. There is provided a top side platform (402) for a voltage source converter high voltage direct current, VSC, HVDC, symmetric unipolar offshore converter station, the top side platform (402) comprising a first layer (404) and a second layer (405), an input AC switchgear module (454), and first and second transformer modules (446, 448), wherein the input AC switchgear module (454) is configured to distribute a first AC signal from an alternating current (AC) grid to the first and second transformer modules (446, 448), where the first and second transformer modules (446, 448) are arranged on a first layer (404) of the top side platform (402) and configured to transform the first AC signal into a second AC signal; and first and second converter modules (410, 412) configured to convert a second AC signal into a DC signal for a direct current (DC) circuit, where the first and second converter modules (410, 412) are located on a second layer (405) of the top side platform (402), where the input AC switching device module (454) is located between the first and second converter modules (410, 412).

Description

Technical Field

[0001] The subject matter herein relates generally to the field of power transmission networks, and more particularly, to offshore converter platforms in power transmission networks. Background Art

[0002] In a high voltage direct current (HVDC) power transmission network, alternating current (AC) power is typically converted to direct current (DC) power for transmission via overhead lines, submarine cables, and / or underground cables. This conversion removes the need to compensate for the AC reactive / capacitive loading effects imposed by the power transmission medium (i.e., the transmission line or cable), and reduces the cost per kilometer of the line and / or cable, and thus becomes cost-effective when power needs to be transmitted over long distances. For example, DC power can also be transmitted directly from an offshore wind farm to an onshore AC power transmission network.

[0003] Where DC and AC power grids have to be interconnected, conversion between DC power and AC power is utilized. In any such power transmission network, power conversion components, also called converters (i.e., power converters in converter stations) are required at each interface between AC and DC power to achieve the required conversion from AC to DC or from DC to AC.

[0004] The selection of the most suitable HVDC power transmission network or scheme depends on the specific application and scheme characteristics.Examples of power transmission networks include unipolar power transmission networks and bipolar power transmission networks.

[0005] The HVDC power transmission network may include one or more offshore HVDC converter platforms. The offshore HVDC converter platform has emerged as a key component for renewable energy to be incorporated into the global power grid. The offshore HVDC converter platform receives the power generated by the offshore wind turbine in the form of alternating current (AC). One of the main functions of the platform is to convert this AC power into high voltage direct current (DC). This conversion is essential for renewable energy transmission systems. These structures serve as the key to efficiently and reliably transmitting the power generated from offshore wind farms and other renewable sources to the onshore power grid.

[0006] There is a continuing need for further development in this area. Summary of the invention

[0007] An offshore HVDC converter typically includes several high voltage and auxiliary equipment mounted on a topside platform. This equipment is arranged in different chambers, referred to as modules, which are interconnected via electrical and / or mechanical interfaces to achieve the desired operation of the offshore HVDC converter platform. The topside platform may be mounted on top of a support structure such as a platform jacket. It is generally desirable to arrange the equipment on the topside platform so that the total footprint, volume and / or weight of the platform is minimized.

[0008] According to a first aspect, a topside platform for a voltage source converter (HVDC) symmetrical monopole offshore converter station is provided, the topside platform comprising: a first layer and a second layer, an input AC switchgear module, a first and a second transformer module, and a first and a second converter module, wherein the input AC switchgear module is configured to distribute a first AC signal from an AC power grid to the first and second transformer modules, wherein the first and the second transformer modules are arranged on the first layer of the topside platform and are configured to transform the first AC signal into a second AC signal; and first and second converter modules, which are configured to convert the second AC signal into a DC signal for a DC circuit, wherein the first and the second converter modules are located on the second layer of the topside platform, wherein the input AC switchgear module is located between the first and the second converter modules.

[0009] The first layer may be above the second layer, ie vertically above or on top of the second layer.

[0010] Therefore, the topside platform has a reduced total footprint, volume and weight. In addition, the topside platform is easier to assemble, transport and install, thereby providing a more economical overall solution.

[0011] It will be appreciated that the use of the terms "first," "second," etc. is merely intended to help distinguish similar features and is not intended to indicate the relative importance of one feature to another, unless otherwise specified.

[0012] Within the scope of the present application, it is expressly intended that the various aspects, embodiments, examples and alternatives set forth in the preceding paragraphs and claims and / or the following description and drawings, and in particular the individual features therein, may be employed independently or in any combination. That is, all embodiments and all features of any embodiment may be combined in any manner and / or combination, unless such features are incompatible. The present invention provides a set of technical solutions, as follows. Technical Solution 1. A topside platform (402) for a voltage source converter high voltage direct current (VSC) HVDC symmetrical monopolar offshore converter station, the topside platform (402) comprising: a first layer (404) and a second layer (405), an input AC switchgear module (454), and first and second transformer modules (446, 448), wherein the input AC switchgear module (454) is configured to distribute a first AC signal from an alternating current (AC) grid to the first and second transformer modules (446, 448), wherein the first and second transformer modules (446, 448) are arranged on the first layer (404) of the topside platform (402) and are configured to transform the first AC signal into a second AC signal; and First and second converter modules (410, 412), the first and second converter modules (410, 412) being configured to convert the second AC signal into a DC signal for a direct current (DC) circuit, wherein the first and second converter modules (410, 412) are located on the second layer (405) of the topside platform (402), wherein the input AC switchgear module (454) is located between the first and second converter modules (410, 412). Technical Solution 2. A top side platform (402) according to Technical Solution 1, wherein the mass center of the first and second converter modules (410, 412) is substantially vertically aligned with the mass center of the top side platform (402). Technical Solution 3. A top side platform (402) according to any one of the aforementioned technical solutions, wherein the first layer (404) and the second layer (405) are vertically separated and positioned on the top side platform (402). Technical Solution 4. A top side platform (402) according to any one of the aforementioned technical solutions, wherein the input AC switch device module (454) is located on the second layer (405) of the top side platform (402). Technical Solution 5. A top side platform (402) according to any one of the aforementioned technical solutions, wherein the mass center of the input AC switch device module (454) is substantially vertically aligned with the mass center of the top side platform (402). Technical Solution 6. A top side platform (402) according to any one of the aforementioned technical solutions, wherein the length of the input AC switch device module (454) is parallel to the length of the first converter module (410) and / or the second converter module (412). Technical Solution 7. A top side platform (402) according to any one of the aforementioned technical solutions, wherein the mass center of the first and second transformer modules (446, 448) is substantially vertically aligned with the mass center of the top side platform (402). Technical Solution 8. A top side platform (402) according to any one of the aforementioned technical solutions, wherein the mass center of the first transformer module (446) and the mass center of the second transformer module (448) are substantially vertically aligned with the mass center of the input AC switch device module (454). Technical Solution 9. The top side platform (402) according to any one of the aforementioned technical solutions also includes a converter AC side switch device module (434) located between the first transformer module (446) and the second transformer module (448). Technical Solution 10. A top side platform (402) according to Technical Solution 9, wherein the converter AC switch device module (434) is located on the first layer (404) of the top side platform (402). Technical Solution 11. A top side platform (402) according to Technical Solution 9 or Technical Solution 10, wherein the mass center of the converter AC side switching device (434) is substantially vertically aligned with the mass center of the top side platform (402). Technical Solution 12. According to any one of the aforementioned technical solutions, the top side platform (402) also includes a first platform auxiliary module (472) located on the third layer (406) of the top side platform (402). Technical Solution 13. The top side platform (402) according to Technical Solution 12 also includes a second platform auxiliary module (476) arranged on the third layer (406) of the top side platform (402). Technical Solution 14. A top side platform (402) according to Technical Solution 13, wherein the mass center of the first platform auxiliary module (472) is substantially vertically aligned with the mass center of the first converter module (410), and the mass center of the second platform auxiliary module (476) is substantially vertically aligned with the mass center of the second converter module (412), or vice versa. Technical Solution 15. The top side platform (402) according to any one of the aforementioned technical solutions also includes an AC and / or DC cable module (474) located below the input AC switch device module (454). BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Embodiments of the present invention will now be described, by way of example only, and with reference to the accompanying drawings, in which: Figure 1 An example of a power transmission network is generally shown; Figure 2 A schematic diagram illustrating a configuration of an offshore HVDC converter system according to one or more embodiments. Figure 3a Shown is a front view of an offshore HVDC converter platform according to one or more embodiments. Figure 3b According to one or more embodiments, Figure 3a A perspective view of the first level of the offshore HVDC converter platform. Figure 4 According to one or more embodiments, Figure 3a A floor plan of the second level of the offshore HVDC converter platform. Figure 5 According to one or more embodiments, Figure 3a A perspective view of an offshore HVDC converter platform shown in FIG. Figure 6 Shown is a front view of an offshore HVDC converter platform according to one or more embodiments. DETAILED DESCRIPTION

[0014] Figure 1 An example of a power transmission network 100 is generally illustrated. The illustration is not intended to be limited to representing a specific power transmission scheme, such as a monopolar or bipolar HVDC transmission network, but is also provided to illustrate a general example of the operating principles of a power transmission network that is useful for understanding the present invention. In this way, for example, the power transmission network 100 can generally represent a monopolar or bipolar scheme, or can represent a multi-terminal power transmission scheme. Therefore, although specific features in the illustration are shown as being connected to each other using a specific number of connections, it will be understood that this is not intended to be limiting, but rather illustrates the general connection between features / components. Relatedly, the relative sizes or distances between components perceived in the illustration are also not intended to be limiting. Therefore, it will be understood that, for example, the principles and features discussed in the network 100 and herein can be applied to a network including a controller.

[0015] The power transmission network 100 illustrates a first power conversion component 110 (also referred to as a converter station) and a second power conversion component 120. The power conversion components 110, 120 convert AC power to DC power (and vice versa), essentially acting as rectifiers (when converting AC power to DC power for transmission) and inverters (when receiving DC power and converting it to AC power). In the case of a unipolar system, the power conversion components 110, 120 may each include a single converter, or include two converters in the case of a bipolar system. The power conversion components 110, 120 may represent multiple converter stations arranged as a multi-terminal power transmission system. In general, the first power conversion component 110 includes a first AC side 110a and a first DC side 110b. In general, the second power conversion component 120 includes a second AC side 120a and a second DC side 120b.

[0016] The first power conversion component 110 is connected to a first AC network 140. The first AC network 140 is connected to a first AC side 110a of the first power conversion component 110.

[0017] The second power conversion component 120 is connected to a second AC network 150. The second AC network 150 is connected to a second AC side 120a of the second power conversion component 120. The first AC network 140 and / or the second AC network 150 may be an electric power transmission system, which includes a power generation device, a transmission device, a distribution device and an electric load. The first AC network 140 and / or the second AC network 150 may include a renewable power generation network, such as a wind power generation network, a solar power generation network, a biopower generation network. The first AC network 140 or the second AC network 150 may be a consumer network. By way of non-limiting example, for example, the first AC network 140 may be a power generation network, wherein the second AC network 150 is a consumer network.

[0018] Also shown is a power transmission medium 130 that interconnects the first power conversion component 110 and the second power conversion component 120. The power transmission medium 130 is connected between the first DC side 110b of the first power conversion component 110 and the second DC side 120b of the second power conversion component 120. The power transmission medium 130 may include cables and other electrical components that interconnect the first and second power conversion components 110, 120. For example, the power transmission medium 130 may include a conductor that provides a first electrode; and / or a conductor that provides a second electrode. A neutral arrangement that interconnects the first and second power conversion components 110, 120 may also be provided. The power transmission medium 130 provides a medium through which DC power is transmitted between the power conversion components 110, 120.

[0019] It will be appreciated that various other electrical components may be located in any particular location or have any particular features / components in example 100. These electrical components may include switches, transformers, resistors, reactors, surge arresters, harmonic filters, and other components known in the art.

[0020] It will be appreciated that the converter or power conversion component may comprise a variety of different technologies, such as a voltage source converter (e.g. using insulated gate bipolar transistor (IGBT) valves). Such a converter may generally be considered to use 'power electronics'. For example, a power electronic converter may comprise a multi-level voltage source converter.

[0021] The power transmission network 100 may also include a controller for controlling the operation of the components of the power transmission network 100. For example, a controller may be provided for performing the methods described herein. For example, such a controller may control the power conversion components 110, 120. Such a controller may be referred to as a controller component or a control component.

[0022] Figure 2 A schematic diagram of a system configuration of an offshore HVDC converter system, generally indicated by reference numeral 200 , is shown in accordance with one or more embodiments.

[0023] The offshore HVDC converter system 200 may be a voltage source converter (VSC) HVDC symmetrical monopolar offshore converter station. The size of the equipment and layout in the offshore converter platform may be a function of the power and DC voltage level of the VSC HVDC system 200. The VSC HVDC system 200 includes the following basic modules / chambers and / or components: ■AC array cable 262; ■ Input AC switchgear 252 (eg, this may be configured for 66 kV and / or 132 kV power); ■ Transformer 1 module 242; ■ Transformer 2 module 244; ■ Converter AC side switchgear 232 (for example, this may be configured for 420 kVAC for a 320 kV DC voltage, or for 550 kV AC for a 400 kV DC voltage); ■ a forward converter module 210 (which may include one or more of a converter valve, a reactor and a DC switchgear); ■ a negative converter module 212 (which may include one or more of a converter valve, a reactor, and a DC switchgear); ■DC outlet cable 222.

[0024] The VSC HVDC system 200 may further include: ■ Converter valve cooling chamber (not shown); ■ Platform cooling room - seawater, fresh water cooling, etc. (not shown); ■ Air conditioning room (not shown); ■Electrical LV auxiliary room (not shown); ■C&P and Automation Room (not shown).

[0025] The main circuit equipment electrical connections and switch equipment layout may depend on the operating circuit configuration requirements. The physical layout of the above modules on the topside platform equipment may depend on one or more of the following criteria / considerations: ■Reduce the total footprint of the topside platform; ■Reduce the total volume of the topside platform; ■Reduce the total weight of the top side platform. ■Reduce the complexity of offshore converter platform assembly. ■ Ensure that the center of gravity (or center of mass) of the top side platform is located at (or close to) the geometric center of the top side platform. ■ Ensure that the transportation and installation of the platform is safe and economical. ■ Ensure that the equipment layout and connections meet the main electrical circuit connection requirements. ■ Ensure that there are adequate maintenance, electrical and / or safety distances between the equipment and electrical connections. ■Ensure safe operation and maintenance of the station. ■ Reduce the overall cost and time required to build a converter station. ■Reduce the total loss and unavailability of the solution.

[0026] Figure 3a 4. An elevation view of an offshore HVDC converter platform generally indicated by reference numeral 400 is shown according to one or more embodiments. According to some embodiments, the offshore HVDC converter platform 400 is a Figure 2 A VSC HVDC symmetrical monopole offshore converter station 200 is described.

[0027] The offshore HVDC converter platform 400 comprises a topside platform 402 mounted on a support structure 403. The support structure 403 may be a platform jacket attached or anchored to the seabed.

[0028] The length of the top platform 402 is the horizontal dimension of the top platform 402, i.e., the length of the top platform 402 extending horizontally through the top platform 402. Figure 3a The width of the top platform 402 is the horizontal dimension of the top platform 402, i.e., the width of the top platform 402. Figure 3a The height of the top platform 402 is the vertical dimension of the top platform 402, i.e. Figure 3a The vertical top of the page, that is, along the y-axis.

[0029] The topside platform 402 includes a first layer 404 on which the following modules / chambers, electronic components and / or mechanical components are located: ■ a first transformer module 446 comprising a first transformer 442; ■ a second transformer module 448 comprising a second transformer 444; ■Converter AC side switch device module (in Figure 3b 434), which includes a converter AC side switching device (in Figure 3b , and indicated by reference numeral 432); and ■Module or space (in Figure 3b , and indicated by reference numeral 479), which may be below the converter AC side switchgear module 434 and may be used for platform auxiliary components.

[0030] The converter AC side switchgear module 434 is located at the geometric horizontal center of the first layer 404. The first transformer module 446 and the second transformer module 448 are located on either side of the converter AC side switchgear module 434. In other words, the converter AC side switchgear module 434 is sandwiched between the first transformer module 446 and the second transformer module 448. Starting from one side of the first layer 404, the modules are arranged in the following order (along the z-axis): 1) first transformer module 446; 2) converter AC side switchgear module 434; 3) second transformer module 448.

[0031] The length of the first transformer module 446 is the horizontal dimension of the first transformer module 446, i.e., along the z-axis. The width of the first transformer module 446 is the horizontal dimension of the first transformer module 446, i.e., along the x-axis. The height of the first transformer module 446 is the vertical dimension of the first transformer module 446, i.e., Figure 3a The vertical top of the page, that is, along the y-axis.

[0032] The length of the second transformer module 448 is the horizontal dimension of the second transformer module 448, i.e., along the z-axis. The width of the second transformer module 448 is the horizontal dimension of the second transformer module 448, i.e., along the x-axis. The height of the second transformer module 448 is the vertical dimension of the second transformer module 448, i.e., Figure 3a The vertical top of the page, that is, along the y-axis.

[0033] The length of the converter AC side switchgear module 434 is the dimension of the converter AC side switchgear module 434, i.e., along the z-axis. The width of the converter AC side switchgear module 434 is the horizontal dimension of the converter AC side switchgear module 434, i.e., along the x-axis. The height of the converter AC side switchgear module 434 is the vertical dimension of the converter AC side switchgear module 434, i.e., Figure 3a The vertical top of the page, that is, along the y-axis.

[0034] The topside platform 402 also includes a second layer 405 on which the following modules / chambers, electronic components and / or mechanical components are located: ■ A first converter module (eg converter+DC yard chamber 1) 410 including converter valves 413a to 413c; ■ A second converter module (eg, converter+DC field chamber 2) 412 including converter valves 413d to 413f; ■ Input AC switchgear module 454 (sometimes referred to as a gas insulated switchgear (GIS) room), including input AC switchgear 452 and its control and protection (C&P) module 456; ■ Module 478 for converter cooling chamber, C&P and platform auxiliary equipment (not shown).

[0035] The first converter module 410 (which may be a positive or negative converter module) and the second converter module 412 (which may be a negative or positive converter module) are separate modules. Each of the first converter module 410 and the second converter module 412 may include one or more converter valves 413a to 413f, valve reactors (not shown), DC switchgear (not shown), and DC cable terminals (not shown).

[0036] The input AC switchgear module 454 is located at the geometric horizontal center of the second layer 405. The module 478 is located above the input AC switchgear module 454. The first converter module 410 and the second converter module 412 are located on either side of the module 478 and the input AC switchgear module 454. In other words, the input AC switchgear module 454 is sandwiched between the first converter module 410 and the second converter module 412. Starting from one side of the second layer 405, the modules are arranged in the following order: 1) the first converter module 410; 2) the module 478 and the input AC switchgear module 454; 3) the second converter module 412.

[0037] The length of the first converter module 410 is the horizontal dimension of the first converter module 410, i.e., along the z-axis. The width of the first converter module 410 is the horizontal dimension of the first converter module 410, i.e., along the x-axis. The height of the first converter module 410 is the vertical dimension of the first converter module 410, i.e., Figure 3a The vertical top of the page, that is, along the y-axis.

[0038] The length of the second converter module 412 is the horizontal dimension of the second converter module 412, i.e., along the z-axis. The width of the second converter module 412 is the horizontal dimension of the second converter module 412, i.e., along the x-axis. The height of the second converter module 410 is the vertical dimension of the second converter module 410, i.e., Figure 3a The vertical top of the page, that is, along the y-axis.

[0039] The length of the input AC switchgear module 454 is the horizontal dimension of the input AC switchgear module 454, i.e., along the z-axis. The width of the input AC switchgear module 454 is the horizontal dimension of the input AC switchgear module 454, i.e., along the x-axis. The height of the input AC switchgear module 454 is the vertical dimension of the input AC switchgear module 454, i.e., Figure 3aThe vertical top of the page, that is, along the y-axis.

[0040] The first converter module 410 and the second converter module 412 may be located on the second level 405 in a symmetrical butterfly arrangement. The first converter module 410 and the second converter module 412 are located at the same elevation / level on the topside platform 402. Arranging the first converter module 410 and the second converter module 412 at the same elevation and in a symmetrical butterfly arrangement on the second level 405 balances the load on the support structure 403 (e.g., platform jacket). In this arrangement, the length of the first converter module 410 and the second converter module 412 may define the width of the entire topside platform 402. In addition, since the converter valves, reactors, DC switchgear, and DC cable terminals are combined in one module, this arrangement may also reduce the need for one or more wall bushings in the first converter module 410 and the second converter module 412. This arrangement tends to reduce the total footprint of the first converter module 410 and the second converter module 412. The reduction in the total volume of the first converter module 410 and the second converter module 412 may also improve or facilitate the air conditioning requirements of these rooms.

[0041] The length of the input AC switchgear module 454 can be the same or similar to the length of the first and second converter modules 410, 412. Placing the input AC switchgear module 454 in a longitudinal arrangement next to the first and second converter modules 410, 412 tends to reduce the overall footprint of the second layer 405, and tends to improve connections to the array cables, which can be routed through a cable room below the input AC switchgear module 454. Route the array cables through a cable (pulling) room in the middle of the topside platform 402 (and spread across the width of the topside platform 402) can give more freedom to place the J-tubes on the support structure 403 (e.g., conduit) legs, and each simplifies cable pulling.

[0042] The input AC switch device module 454 is shown as being on the same layer (ie, second layer 405 ) as the first and second converter modules 410 , 412 ; however, in some embodiments, the input AC switch device module 454 may be on a different layer than the first and second converter modules 410 , 412 .

[0043] In some embodiments, the topside platform 402 may also include a third layer 406 on which the following modules / chambers, electronic components, and / or mechanical components are located: ■ A first platform auxiliary module 472, which may include one or more of heating ventilation and air conditioning (HVA / C), platform cooling systems (seawater and freshwater systems), and / or low pressure (LV) auxiliary systems; ■ a second platform auxiliary module 476 , which may include one or more of the HVA / C platform cooling system and / or the LV auxiliary system; ■ Modules for inputting AC and / or DC cables 474 . In some embodiments, DC cables 474 may enter modules 410 and 412 directly.

[0044] The third layer 406 is below the second layer 405 (ie, closer to the sea) to enable access to seawater (or fresh water) for platform cooling.

[0045] The module for inputting AC and / or DC cables 474 is located at the geometric horizontal center of the third layer 406. The first platform auxiliary module 472 and the second platform auxiliary module 476 are located on either side of the module for inputting AC and / or DC cables module 474. In other words, the module for inputting AC and / or DC cables 474 is sandwiched between the first platform auxiliary module 472 and the second platform auxiliary module 476. Starting from one side of the third layer 406, the modules are arranged in the following order: 1) the first platform auxiliary module 472; 2) the module for inputting AC and DC cables module 474; 3) the second platform auxiliary module 476.

[0046] Compared with similar structures in the prior art, Figure 3a Arranging the first layer 404, the second layer 405, and the third layer 406 of the topside platform 402 as shown in the figure tends to reduce the total footprint, volume, and weight of the topside platform 402. In addition, compared with similar structures in the prior art, the arrangement tends to simplify the manufacture / assembly of the topside platform and tends to simplify the transportation and installation of the topside platform 402. Compared with similar structures in the prior art, the arrangement also tends to provide a more economical overall solution.

[0047] Positioning the first and second transformer modules 446, 448 and the converter AC side switchgear module 434 on the first layer 404 further tends to reduce the overall volume and weight of the topside platform 402. The first layer 404 is above the second layer 405. The first and second transformer modules 446, 448 and the converter AC side switchgear module 434 are placed on top of the topside platform 402 such that they are outside of the main topside structure.

[0048] In some embodiments (such as Figure 3a ), the first transformer module 446 is directly above the module 478. In some embodiments (such as Figure 3a ), the second transformer module 448 is also located directly above the module 478.

[0049] In some embodiments, the combined length of the first and second transformer modules 446 , 448 and the converter AC side switch device module 434 is the same or similar to the individual lengths of the first converter module 410 and / or the second converter module 412 and / or the input AC switch device module 454 .

[0050] In some embodiments (e.g., Figure 6 ), the first and second transformer modules 446, 448 and the converter AC side switchgear module 434 may be arranged in the center of the top side platform 402 and along the length of the input AC switchgear module 454. The converter AC side switchgear module 434 may be located in the middle of the first transformer module 446 and the second transformer module 448 on the first layer 404. This arrangement improves the connection between the converter AC side switchgear module 434 and the first and second transformer modules 446, 448. In addition, this arrangement improves the connection between the converter AC side switchgear module 434 and the first and second converter modules 410, 412.

[0051] In some embodiments, the first and second transformer modules 446, 448 are formed as part of the main structure of the topside platform 402. This can lower the center of gravity (and / or center of mass) of the topside platform 402.

[0052] In some embodiments, the first transformer module 446 can be directly above the first converter module 410. In some embodiments, the second transformer module 448 can be directly above the second converter module 412.

[0053] In some embodiments, the first and second transformer modules 446, 448 are formed as part of the main structure of the topside platform 402. This can lower the center of gravity (and / or center of mass) of the topside platform 402.

[0054] In some embodiments, the locations of the first and second transformer modules 446, 448 and the converter AC side switch device 446 can be selected to improve the structural design and center of gravity (and / or center of mass) to allow easy transportation and installation of the first and second transformer modules 446, 448 and the converter AC side switch device 446.

[0055] The AC line side connection between the input AC switchgear module 454 and the first and second transformer modules 446, 448 may be provided by a gas insulated bus (GIB). The GIB may extend from the input AC switchgear module 454 to the top of the topside platform 402 by a dedicated conduit. However, connection by cables is also possible.

[0056] In some embodiments, module 478 includes a converter cooling chamber and C&P components. Module 478 is arranged on top of input AC switchgear module 454, which tends to improve the interface with first and second converter modules 410, 412. This tends to reduce the complexity of cooling pipes and optical fibers extending from module 478 (which includes the converter cooling chamber and C&P components) to first and second converter modules 410, 412. In some embodiments, module 478 may further include additional auxiliary equipment / chambers.

[0057] In some embodiments, the first layer 404 may include one or more of additional platform accessories, water to air coolers, diesel generators, telecommunications rooms, filters, and grounding reactors.

[0058] Figure 3b An example of a schematic diagram of a device shown generally indicated by reference numeral 490 in accordance with one or more embodiments is shown. Figure 3a A perspective view of the first level of the offshore HVDC converter platform.

[0059] The perspective view 490 includes a first layer 490, which includes a first layer 404 of the top platform 402; Figure 3a The first layer 404 includes the following modules / rooms, electronic components and / or mechanical components are located: ■ a first transformer module 446 comprising a first transformer 442; ■ a second transformer module 448 comprising a second transformer 444; ■ a converter AC side switchgear module 434 including a converter AC side switchgear 432; and ■Module or space 479, which may be below the converter AC side switchgear module 434 and may be used for platform auxiliary components.

[0060] Figure 4 A plan view of a second level 405 of an offshore HVDC converter platform 400 is shown according to one or more embodiments.

[0061] The length of the top platform is the horizontal dimension of the top platform, i.e. the length of the top platform that passes horizontally through the Figure 4 The width of the top platform is the horizontal dimension of the top platform, i.e. Figure 4 The vertical top of the page, that is, along the z-axis.

[0062] The length of the first converter module 410 is the horizontal dimension of the first converter module 410, ie Figure 4 The width of the first converter module 410 is the horizontal dimension of the first converter module 410, i.e., the ... Figure 4 of pages, that is, along the x-axis.

[0063] The length of the second converter module 412 is the horizontal dimension of the second converter module 412, i.e. Figure 4 The width of the second converter module 412 is the horizontal dimension of the second converter module 412, i.e., the width of the second converter module 412 is the horizontal dimension of the second converter module 412. Figure 4 of pages, that is, along the x-axis.

[0064] The length of the input AC switchgear module 454 is the horizontal dimension of the input AC switchgear module 454, i.e. Figure 4 The width of the input AC switchgear module 454 is the horizontal dimension of the input AC switchgear module 454, i.e., the width of the input AC switchgear module 454 across the vertical axis of the page. Figure 4 of pages, that is, along the x-axis.

[0065] The second layer 400 includes a first converter module 410 , an input AC switchgear module 454 , and a second converter module 412 .

[0066] The first converter module 410 includes a first converter valve 413a, a second converter valve 413b and a third converter valve 413c. The first converter module 410 also includes a first DC switch device 414a. The first converter module 410 also includes a first valve reactor 415a, a second valve reactor 415b and a third valve reactor 415c.

[0067] The second converter module 412 includes a fourth converter valve 413d, a fifth converter valve 413e, and a sixth converter valve 413f. The second converter module 412 also includes a second DC switch device 414b. The second converter module 412 also includes a fourth valve inductor 415d, a fifth valve inductor 415e, and a sixth valve inductor 415f.

[0068] The input AC switchgear module 454 includes the input AC switchgear 452 and its input AC switchgear C&P 456 .

[0069] Input AC switchgear 452 and input AC switchgear C&P 456 are positioned parallel to each other (along their lengths) and are located in the center of the second layer 400 .

[0070] The length of the first converter module 410 and the second converter 412 is the same (or similar) as the length of the input AC switchgear module 454. The first converter module 410 and the second converter 412 are positioned parallel to (along their lengths) the input AC switchgear module 454. In addition, the first converter module 410 and the second converter 412 are located on either side of the input AC switchgear module 454.

[0071] The arrangement of modules and components shown in the second layer 400 may further improve the structural design of the topside platform by transferring the loads of the first and second transformer modules to the main center beam of the topside platform.

[0072] Figure 5 Shows Figure 3a A perspective view of an offshore HVDC converter platform 400 in FIG.

[0073] Figure 6 600 is a front view of an offshore HVDC converter platform according to one or more embodiments. According to some embodiments, the offshore HVDC converter platform 600 is a Figure 2 A VSC HVDC symmetrical monopole offshore converter station 200 is described.

[0074] The offshore HVDC converter platform 600 comprises a topside platform 602 mounted on a support structure 403. The support structure 403 may be a platform jacket attached or anchored to the seabed.

[0075] The length of the top platform 602 is the horizontal dimension of the top platform 602, i.e., the length of the top platform 602 extending horizontally through the top platform 602. Figure 6 The width of the top platform 602 is the horizontal dimension of the top platform 602, i.e., the width of the top platform 602. Figure 6 The height of the top platform 602 is the vertical dimension of the top platform 602, i.e. Figure 6 The vertical top of the page, that is, along the y-axis.

[0076] The topside platform 602 includes a first layer 604, the following modules / chambers, electronic components and / or mechanical components (which are related to Figures 3a to 5 The corresponding modules / chambers, electronic components and / or mechanical components described are the same) are located on the first layer 604: ■ a first transformer module 446 comprising a first transformer 442; ■ a second transformer module 448 comprising a second transformer 444; ■ a converter AC side switchgear module, indicated by reference numeral 434 , comprising a converter AC side switchgear, indicated by reference numeral 432 ; and ■ A module or space indicated by reference numeral 479 which may be below the converter AC side switchgear module 434 and may be used for platform auxiliary components.

[0077] The converter AC side switchgear module 434 is located at the geometric horizontal center of the first layer 604. The first transformer module 446 and the second transformer module 448 are located on either side of the converter AC side switchgear module 434. In other words, the converter AC side switchgear module 434 is sandwiched between the first transformer module 446 and the second transformer module 448. Starting from one side of the first layer 604, the modules are arranged in the following order (along the x-axis): 1) first transformer module 446; 2) converter AC side switchgear module 434; 3) second transformer module 448.

[0078] The length of the first transformer module 446 is the horizontal dimension of the first transformer module 446, i.e., along the x-axis. The width of the first transformer module 446 is the horizontal dimension of the first transformer module 446, i.e., along the z-axis. The height of the first transformer module 446 is the vertical dimension of the first transformer module 446, i.e., Figure 6 The vertical top of the page, that is, along the y-axis.

[0079] The length of the second transformer module 448 is the horizontal dimension of the second transformer module 448, i.e., along the x-axis. The width of the second transformer module 448 is the horizontal dimension of the second transformer module 448, i.e., along the z-axis. The height of the second transformer module 448 is the vertical dimension of the second transformer module 448, i.e., Figure 6 The vertical top of the page, that is, along the y-axis.

[0080] The length of the converter AC side switchgear module 434 is the dimension of the converter AC side switchgear module 434, i.e., along the x-axis. The width of the converter AC side switchgear module 434 is the horizontal dimension of the converter AC side switchgear module 434, i.e., along the z-axis. The height of the converter AC side switchgear module 434 is the vertical dimension of the converter AC side switchgear module 434, i.e., Figure 6 The vertical top of the page, that is, along the y-axis.

[0081] The top platform 402 also includes a second layer 405, which is connected to the above Figures 3a to 5 The second layer 405 is described identically.

[0082] In some embodiments, the top platform 402 may further include a third layer 406, which is similar to the third layer 406 described above. Figures 3a to 5 The third layer 406 is described identically.

[0083] Compared with similar structures in the prior art, Figure 6Arranging the first layer 604, the second layer 405, and the third layer 406 of the topside platform 602 as shown in the figure tends to reduce the total footprint, volume, and weight of the topside platform 602. In addition, compared with similar structures in the prior art, the arrangement tends to simplify the manufacture / assembly of the topside platform and tends to simplify the transportation and installation of the topside platform 602. Compared with similar structures in the prior art, the arrangement also tends to provide a more economical overall solution.

[0084] Positioning the first and second transformer modules 446, 448 and the converter AC side switchgear module 434 on the first layer 604 further tends to reduce the overall volume and weight of the topside platform 602. The first layer 604 is above the second layer 405. The first and second transformer modules 446, 448 and the converter AC side switchgear module 434 are placed on top of the topside platform 602 such that they are outside of the main topside structure.

[0085] In some embodiments, the first and second transformer modules 446, 448 are formed as part of the main structure of the topside platform 602. This can lower the center of gravity (and / or center of mass) of the topside platform 602.

[0086] In some embodiments, the first and second transformer modules 446, 448 are formed as part of the main structure of the topside platform 602. This can lower the center of gravity (and / or center of mass) of the topside platform 602.

[0087] In some embodiments, the first layer 604 may include one or more of additional platform accessories, water to air coolers, diesel generators, telecommunications rooms, filters, and grounding reactors.

[0088] In a first aspect, a topside platform for a voltage source converter high voltage direct current (VSC HVDC) symmetrical monopole offshore converter station, the topside platform comprising: a first layer and a second layer, an input AC switchgear module, and first and second transformer modules, wherein the input AC switchgear module is configured to distribute a first AC signal from an alternating current (AC) grid to the first and second transformer modules, wherein the first and second transformer modules are arranged on the first layer of the topside platform and are configured to transform the first AC signal into a second AC signal; and first and second converter modules, which are configured to convert the second AC signal into a DC signal for a direct current (DC) circuit, wherein the first and second converter modules are located on the second layer of the topside platform, wherein the input AC switchgear module is located between the first and second converter modules.

[0089] Therefore, the topside platform in the first aspect has a reduced total footprint, volume and weight. In addition, the topside platform is easier to assemble, transport and install, thereby providing a more economical overall solution.

[0090] The centers of mass of the first and second converter modules may be substantially vertically aligned with the center of mass of the topside platform.

[0091] The topside platform may be part of a support structure. The topside platform may be mounted on top of the support structure. The support structure may be a platform jacket. The support structure may be designed to keep the VSC HVDC station on or relatively stable relative to the seabed. The support structure may include a fixed platform, a floating platform, or a gravity-based structure attached to the seabed. The topside platform may include multiple layers.

[0092] The vertical direction may be relative to the seabed. The topside platform may be arranged on top of the support structure. The vertical direction may be relative to the topside platform.

[0093] The input AC switchgear may receive a first AC signal from an AC grid (such as a utility grid or a generator). The alternating current (AC) grid may be on a wind farm offshore grid. The input AC switchgear module may direct the first AC signal from the AC grid to the first and / or second transformer modules.

[0094] The input AC switchgear may control power distribution from the first AC signal within the first and second transformer modules.The input AC switchgear may include one or more of a circuit breaker, a disconnect switch, a fuse, a surge arrester, a current transformer, and a voltage transformer.

[0095] The first and second transformer modules may each include a transformer configured to transform the voltage of the first AC signal. The first or second transformer module may increase the voltage of the first AC signal. The second AC signal may have a higher voltage than the first AC signal. The first or second transformer module may reduce the voltage of the first AC signal. The second AC signal may have a lower voltage than the first AC signal.

[0096] The first and second converter modules may each comprise an electrical device for converting the second AC signal into a DC signal.The first and second converter modules may operate as rectifiers or inverters.

[0097] The DC signal may be a positive DC signal. The DC signal may be a negative DC signal.

[0098] The first converter module may be a positive converter module and the second converter module may be a negative converter module. The first converter module may be a negative converter module and the second converter module may be a positive converter module.

[0099] The first converter module may be located on the same layer / level of the topside platform as the second converter module. The first converter module may be located on the same horizontal plane as the second converter module. The first converter module may be coplanar with the second converter module.

[0100] Both the first converter module and the second converter module may be located on the second layer of the topside platform such that centers of mass of the first converter module and the second converter module are substantially vertically aligned with a center of mass of the topside platform.

[0101] The first converter module and the second converter module may be arranged symmetrically about a vertical axis, wherein the vertical axis may be substantially perpendicular to the second layer of the topside platform.

[0102] The first converter module and the second converter module may be arranged such that the load / weight of the first converter module and the second converter module is balanced laterally (horizontally) above the topside platform.

[0103] The vertical axis may pass through the center of mass of the top platform. The vertical axis may pass through the center of mass of the second layer of the top platform. The vertical axis may overlap with the center of mass of the top platform. The vertical axis may overlap with the center of mass of the second layer of the top platform.

[0104] The centre of mass of the first and second converter modules may be the centre of mass of their combined mass and relative position.The centre of mass of the first and second converter modules may not be the centre of mass of the first converter module and (separately) the centre of mass of the second converter module.

[0105] The length of the first converter module and / or the length of the second converter module may be substantially the width of the topside platform.

[0106] The first and second converter modules may each comprise one or more of a converter valve, a valve reactor, a DC switchgear and / or a DC transmission terminal.

[0107] The first converter module and the second converter module may be physically separate modules. This improves the overall footprint of the first converter module and the second converter module on the topside platform. Furthermore, it may reduce the need for a wall bushing between the first converter module and the second converter module.

[0108] The first converter module and the second converter module may be separated on the second layer. A gap may exist between the first converter module and the second converter module. The width of the gap may be at least the width of the input AC switchgear module. The input AC switchgear module may be arranged in the gap.

[0109] The first converter module may be adjacent to the input AC switchgear module.The second converter module may be adjacent to the input AC switchgear module.

[0110] The first and second transformer modules may not vertically overlap the first and second converter modules.

[0111] The first and second transformer modules may be located on the first layer of the topside platform such that the mass centers of the first and second transformer modules are substantially vertically aligned with the mass center or center of gravity or geometric center of the topside platform. The weight of the first and second transformer modules may be at the center of the topside platform.

[0112] In some embodiments, the first layer and the second layer are vertically separated and positioned on the top platform.

[0113] The topside platform may include a plurality of layers. Each of the plurality of layers may be located at a different elevation (relative to the seabed) on the topside platform. Each of the plurality of layers may be arranged at a separate elevation (relative to the seabed) on the topside platform. Each of the plurality of layers may not vertically overlap with another of the plurality of layers. A first layer may be arranged at an elevation (relative to the seabed) that is separate from a second layer on the topside platform. The first layer may be at a higher elevation (relative to the seabed) than the second layer on the topside platform. The base of the first layer may form the top of the second layer. The first layer may be on a first horizontal plane. The second layer may be on a second horizontal plane. The first horizontal plane may be vertically separated from the second horizontal plane. The first layer may not vertically overlap with the second layer.

[0114] The first and second transformer modules may not vertically overlap the first and second converter modules. The first and second transformer modules may be located on a first layer of the top side platform such that a center of mass of the first transformer module and the second transformer module is substantially vertically aligned with a center of mass or center of gravity or geometric center of the top side. The weight of the first and second transformer modules may be located at a center of the top side.

[0115] The first layer may be arranged at a higher elevation than the second layer on the topside platform. The first layer may be on top of the second layer. The first layer may be physically separated from the second layer. The first layer may not overlap with the second layer. The base of the first layer may be adjacent to the top of the second layer.

[0116] In some embodiments, the input AC switchgear module is located on the second layer of the top side platform.

[0117] The input AC switchgear module may be located on the same layer / level as the first converter module and / or the second converter module of the top side platform. The input AC switchgear module may be located on the same horizontal plane as the first converter module and / or the second converter module. The input AC switchgear module may be coplanar with the first converter module and / or the second converter module.

[0118] The input AC switchgear module may be located on the second layer.The input AC switchgear module may be located at a different layer level than the first converter module and / or the second converter module.

[0119] The first converter module may be located on one side of the second layer. The second converter module may be located on an opposite side of the second layer (relative to the first converter module). The input AC switchgear module may be located between (i.e., in the middle of) the first converter module and the second converter module on the second layer. The input AC switchgear module may be positioned on the second layer in a longitudinal arrangement with the first converter module and the second converter module. The input AC switchgear module may be located between (i.e., in the middle of) the first converter module and the second converter module on the first layer. The input AC switchgear module may be positioned on the first layer in a longitudinal arrangement with the first converter module and the second converter module.

[0120] In some embodiments, the center of mass of the input AC switchgear module is substantially vertically aligned with the center of mass of the topside platform.

[0121] The center of mass of the input AC switchgear module may be substantially vertically aligned with the center of mass of the topside platform. The center of gravity of the input AC switchgear module may be substantially vertically aligned with the center of gravity of the topside platform. The weight of the input AC switchgear may be substantially in the middle of the topside platform.

[0122] In some embodiments, the length of the input AC switchgear module is parallel to the length of the first converter module and / or the second converter module.

[0123] The input AC switchgear module can be parallel to the first converter module and / or the second converter module on the topside platform (i.e., located next to the first converter module and the second converter module in a longitudinal arrangement). The length of the input AC switchgear module can be substantially similar to the first converter module and / or the second converter module. Providing an input AC switchgear module on the topside platform located between and parallel to the first converter module and the second converter module further reduces the footprint of the equipment on the topside platform. In addition, the input AC switchgear module between (i.e., in the middle of) the first and second converter chambers improves the connection with the array cables (which can be pulled through the cable chamber below the input AC switchgear module) and provides more freedom for the J-tubes arranged on the conductor rack legs and each cable pulling.

[0124] The input AC switchgear modules may be positioned along a horizontal axis that intersects the center of mass of the topside platform.

[0125] The input AC switchgear module may be positioned along a horizontal axis intersecting the centroid of the second layer of the second layer of the topside platform.

[0126] The length of the input AC switchgear module may be located along a horizontal axis. The length of the input AC switchgear module may be located along a horizontal axis that intersects the center of mass of the top side platform.

[0127] The input AC switchgear module may be positioned such that a length of the input AC switchgear module is substantially parallel to a length of the first converter module and / or the second converter module on the top side platform.

[0128] In some embodiments, a center of mass of the first and second transformer modules is substantially vertically aligned with a center of mass of the topside platform.

[0129] The center of gravity of the first and second transformer modules may be aligned with the geometric center of the top side.

[0130] The first and second transformer modules may not be arranged directly above the first and second converter modules, but may be arranged above the input switchgear, making the connection from the input AC switchgear to the transformer easy and short. Furthermore, in this arrangement, the weight of the transformer modules is in the center of the top side. The first and second transformer modules may be arranged directly above the first and second converter modules, respectively. The first and second transformer modules may be arranged directly above the second and first converter modules, respectively.

[0131] In some embodiments, a center of mass of the first transformer module and a center of mass of the second transformer module are substantially vertically aligned with a center of mass of the input AC switchgear module.

[0132] The first transformer module and the second transformer module may be located directly above the input AC switchgear module.

[0133] In a first vertical plane, a center of mass of the first transformer module may be aligned with a center of mass of the input AC switchgear module.In a second vertical plane, a center of mass of the second transformer module may be aligned with a center of mass of the input AC switchgear module.

[0134] In a horizontal plane, the first transformer module and the second transformer module may be positioned symmetrically about the center of mass or center of gravity or weight of the topside platform.

[0135] In some embodiments, the top side platform further includes a converter AC side switchgear module located between the first transformer module and the second transformer module.

[0136] The converter AC side switchgear module may be configured to distribute the second AC signal from the first and second transformer modules to the first and second converter modules.

[0137] The converter AC side switchgear may include one or more of a circuit breaker, a disconnect switch, a surge arrester, or a control system.

[0138] The converter AC side switchgear may be arranged on the first layer of the top side platform.

[0139] The converter AC side switch device can be arranged on the second layer of the top side platform.

[0140] The center of mass of the converter AC side switch device can be substantially vertically aligned with the center of mass of the top side platform.

[0141] In some embodiments, the converter AC switchgear module is located on a first layer of the top side platform.

[0142] In some embodiments, the center of mass of the converter AC side switch device is substantially vertically aligned with the center of mass of the top side platform.

[0143] In some embodiments, the topside platform further includes a first platform auxiliary module located on a third layer of the topside platform.

[0144] The first platform auxiliary module may include a platform mechanical auxiliary system. The mechanical auxiliary system may be located where a seawater system, a freshwater system and / or a HVA / C (heating, ventilation and air conditioning) system are installed. The first platform auxiliary module may include a platform electrical auxiliary system. The electrical auxiliary system may be located where a MV (medium voltage) and LV (low voltage) auxiliary system are installed.

[0145] The third layer may be located at an elevation (relative to the seabed) separate from the first layer on the topside platform. The third layer may be arranged at an elevation (relative to the seabed) separate from the second layer on the topside platform. The top of the third layer may form the base of the second layer. The third layer may be on a third horizontal plane. The third horizontal plane may be vertically separated from the first horizontal plane. The third horizontal plane may be vertically separated from the second horizontal plane. The third layer may not vertically overlap with the first layer. The third layer may not vertically overlap with the second layer.

[0146] In some embodiments, the topside platform further includes a second platform auxiliary module disposed on a third layer of the topside platform.

[0147] The second platform auxiliary module may include a platform mechanical auxiliary system. The mechanical auxiliary system may be located at the location where seawater and fresh water are installed. The second platform auxiliary module may include a platform electrical auxiliary system. The electrical auxiliary system may be located at the location where the HVA / C and LV auxiliary systems are installed.

[0148] In some embodiments, a center of mass of the first platform assist module is substantially vertically aligned with a center of mass of the first converter module, and a center of mass of the second platform assist module is substantially vertically aligned with a center of mass of the second converter module, or vice versa.

[0149] In some embodiments, the topside platform further includes a converter cooling module located above or below the input AC switchgear module.

[0150] The converter cooling module may be arranged vertically above the input AC switchgear module.

[0151] The converter cooling module may be arranged between the first converter module and the second converter module. The center of mass of the converter cooling module may be substantially vertically aligned with the center of mass of the input AC switchgear module. The converter cooling module may be located at the geometric center of the first layer. The converter cooling module may be arranged at the center of mass of the top side platform. The converter cooling module may be arranged at the centroid of the first layer. The converter cooling module may overlap with the geometric center of the first layer. The converter cooling module may overlap with the center of mass of the top side platform. The converter cooling module may overlap with the centroid of the first layer. This may improve the interface with the converter chamber. This may further improve the cooling pipes extending from the converter cooling module to the first converter chamber and / or the second converter chamber.

[0152] In some embodiments, the topside platform further includes a control and protection module located on the second layer of the topside platform, adjacent to or directly above the input AC switchgear module.

[0153] The control and protection module may be located on the same layer / level of the topside platform as the first converter module and / or the second converter module. The control and protection module may be located on the same horizontal plane as the first converter module and / or the second converter module. The control and protection module may be coplanar with the first converter module and / or the second converter module.

[0154] The control and protection module may be located at the center of mass of the second layer of the top side platform. The control and protection module may be located at the geometric center of the second layer of the top side platform. The center of mass of the control and protection module may be substantially vertically aligned with the center of mass of the top side platform. The center of mass of the control and protection module may overlap with the center of mass of the second layer of the top side platform. The center of mass of the control and protection module may overlap with the geometric center of the second layer of the top side platform. The center of mass of the control and protection module may overlap with the center of mass of the top side platform.

[0155] The control and protection module may be located directly above the input AC switchgear module.

[0156] The control and protection modules can be used to control and protect the input AC switchgear and the HVDC converter system (converter modules, transformer modules, converter cooling and auxiliary systems). Having a control and protection module on the second level, almost in the middle of every other module, can improve the interface with other modules, thus reducing the length of the control cables. This tends to reduce the complexity of the optical fibers extending from the control and protection modules to the positive converter chamber and / or the negative converter chamber.

[0157] References to examples of specific methods or devices throughout this specification or similar language mean that the specific features, structures, or characteristics described in conjunction with the examples are included in at least one implementation of the methods and devices described herein. The terms "include," "comprises," "comprising," "having," and variations thereof mean "including but not limited to," unless expressly specified otherwise. An enumerated list of items does not imply that any or all of the items in the list are mutually exclusive, unless expressly specified otherwise. The terms "a," "an," and "the" also mean "one or more," unless expressly specified otherwise.

[0158] As used herein, a list with the conjunction "and / or" includes any single item in the list or a combination of items in the list. For example, a list of A, B, and / or C includes only A, only B, only C, a combination of A and B, a combination of B and C, a combination of A and C, or a combination of A, B, and C. As used herein, a list using the term "one or more of..." includes any single item in the list or a combination of items in the list. For example, one or more of A, B, and C includes only A, only B, only C, a combination of A and B, a combination of B and C, a combination of A and C, or a combination of A, B, and C. As used herein, a list using the term "one of..." includes one of any single item in the list and only one of any single item in the list. For example, "one of A, B, and C" includes only A, only B, or only C, and does not include a combination of A, B, and C. As used herein, "a member selected from the group consisting of A, B, and C" includes one and only one of A, B, or C, and does not include a combination of A, B, and C. As used herein, “a member selected from the group consisting of A, B, and C, and combinations thereof” includes only A, only B, only C, a combination of A and B, a combination of B and C, a combination of A and C, or a combination of A, B, and C.

[0159] It will be appreciated that the numerical values ​​cited herein are intended merely to help illustrate the operation of the present invention, and may vary depending on the requirements of a given power delivery network, its components, or power delivery application.

[0160] The listing or discussion of an apparently prior-published document or apparently prior-published information in this specification should not necessarily be taken as an admission that the document or information is part of the prior art or is common general knowledge.

[0161] Unless the context dictates otherwise, preferences and options for a given aspect, feature or parameter of the invention should be considered disclosed in conjunction with any and all preferences and options for all other aspects, features and parameters of the invention.

Claims

1. A topside platform (402) for a voltage source converter high voltage direct current (VSC) HVDC symmetrical monopolar offshore converter station, the topside platform (402) comprising: A first layer (404) and a second layer (405), an input AC switchgear module (454), and first and second transformer modules (446, 448), wherein the input AC switchgear module (454) is configured to distribute a first AC signal from an alternating current (AC) grid to the first and second transformer modules (446, 448), wherein the first and second transformer modules (446, 448) are arranged on the first layer (404) of the topside platform (402) and are configured to transform the first AC signal into a second AC signal; as well as First and second converter modules (410, 412), the first and second converter modules (410, 412) being configured to convert the second AC signal into a DC signal for a direct current (DC) circuit, wherein the first and second converter modules (410, 412) are located on the second layer (405) of the topside platform (402), wherein the input AC switchgear module (454) is located between the first and second converter modules (410, 412).

2. The topside platform (402) according to claim 1, wherein: The centers of mass of the first and second converter modules (410, 412) are substantially vertically aligned with the center of mass of the topside platform (402).

3. The topside platform (402) according to any one of the preceding claims, wherein: The first layer (404) and the second layer (405) are vertically separated and positioned on the top platform (402).

4. The topside platform (402) according to any one of the preceding claims, wherein: The input AC switchgear module (454) is located on the second layer (405) of the topside platform (402).

5. The topside platform (402) according to any one of the preceding claims, wherein: The center of mass of the input AC switchgear module (454) is substantially vertically aligned with the center of mass of the topside platform (402).

6. The topside platform (402) according to any one of the preceding claims, wherein: The length of the input AC switchgear module (454) is parallel to the length of the first converter module (410) and / or the second converter module (412).

7. The topside platform (402) according to any one of the preceding claims, wherein: The centers of mass of the first and second transformer modules (446, 448) are substantially vertically aligned with the center of mass of the topside platform (402).

8. The topside platform (402) according to any one of the preceding claims, wherein: The center of mass of the first transformer module (446) and the center of mass of the second transformer module (448) are substantially vertically aligned with the center of mass of the input AC switchgear module (454).

9. The topside platform (402) of any one of the preceding claims, further comprising a converter AC side switchgear module (434) located between the first transformer module (446) and the second transformer module (448).

10. The topside platform (402) according to claim 9, wherein: The converter AC switchgear module (434) is located on the first layer (404) of the topside platform (402).

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