CN214850510U - Offshore wind power alternating current and direct current networking system - Google Patents

Offshore wind power alternating current and direct current networking system Download PDF

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Publication number
CN214850510U
CN214850510U CN202121280529.5U CN202121280529U CN214850510U CN 214850510 U CN214850510 U CN 214850510U CN 202121280529 U CN202121280529 U CN 202121280529U CN 214850510 U CN214850510 U CN 214850510U
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wind power
offshore wind
converter
direct current
centralized
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赵瑞斌
李春华
孙栩
申旭辉
傅望安
汤海雁
王海明
付明志
秦猛
李铮
兰连军
苏人奇
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Huaneng Clean Energy Research Institute
Clean Energy Branch of Huaneng Zhejiang Energy Development Co Ltd
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Huaneng Clean Energy Research Institute
Clean Energy Branch of Huaneng Zhejiang Energy Development Co Ltd
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    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
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    • Y02E60/60—Arrangements for transfer of electric power between AC networks or generators via a high voltage DC link [HVCD]

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Abstract

The utility model belongs to the technical field of offshore wind power transmission, and discloses an offshore wind power AC/DC networking system, which comprises an offshore wind power DC collection module and a centralized DC-AC converter module; the centralized DC-AC converter module comprises a centralized DC-AC converter and an isolation transformer; the centralized DC-AC converter is connected with the DC output port of the offshore wind power DC collection module and used for converting the DC of the offshore wind power DC collection module into AC, and the AC is boosted by the isolation transformer to form a high-voltage AC output port. The utility model does not adopt the DC-DC converter of the high voltage grade of the full DC networking system, but the offshore wind power direct current collection module generates an alternating current output port through the transformation of the centralized DC-AC converter, the utility model is suitable for the scene that the offshore wind power system based on the direct current collection technology adopts the alternating current transmission grid-connected to send out or adopts the flexible direct current transmission grid-connected to send out; the grid-connected sending-out difficulty and the engineering cost of the offshore wind power system adopting the direct current collection technology can be reduced.

Description

Offshore wind power alternating current and direct current networking system
Technical Field
The utility model belongs to the technical field of marine wind power transmission, in particular to marine wind power AC/DC networking system.
Background
At present, an offshore wind power transmission system mainly comprises three modes: an "ac collection, ac sending" mode, an "ac collection, dc sending" mode, and a "dc collection, dc sending" mode.
During offshore wind power development, the cost of a power transmission system is considered, and a power transmission mode of alternating current collection and alternating current sending is mainly adopted. With the rapid expansion of offshore wind power development scale and the rapid increase of power transmission distance, the power transmission modes of 'alternating current collection and alternating current sending' are limited by equipment capacity, the restrictions of engineering economy and the like are increasingly obvious, and the current research recommends that the 'alternating current collection and direct current sending' mode is adopted as a main mode. Meanwhile, with the large capacity of offshore wind power generation sets, the large scale of wind power stations and the rapid development of the trend of the long-distance offshore power transmission distance, the direct-current offshore wind power generation sets are adopted, and the large-scale offshore wind power generation sets are widely concerned in the direct-current collection and direct-current sending power transmission mode.
The full direct current networking mode of 'direct current collection and direct current output' of offshore wind power is that wind power collection is carried out in a mode of series connection, parallel connection, 'series-parallel connection' or 'parallel-series connection' of direct current wind power units, the full direct current networking mode has the advantages of few collection cables, large transmission capacity, small loss, strong controllability of a collection system and the like, and is an important trend of development of large offshore wind power plants in the future.
The offshore wind power full-direct-current networking system boosts the collected direct-current voltage to a high-voltage level after the direct-current wind power units are connected in series, and can directly transmit electric energy to a land electric power system without other links; or a series-parallel or parallel-series mode of the direct current wind turbine generator set can be adopted to form an offshore wind power direct current collection system, and the offshore wind power direct current collection system is connected to a direct current power transmission grid-connected system through a centralized DC-DC converter to transmit electric energy to an onshore electric power system.
At present, aiming at the mode that an offshore wind power full-direct-current networking system is directly transmitted to a land power system, as a wind turbine bears the high voltage of the whole full-direct-current networking system, great technical difficulty exists in realizing the voltage resistance and insulation of the wind turbine; meanwhile, reliable coordination control is carried out on a large number of series wind generation sets, and great technical challenges also exist.
Aiming at the mode that the direct current wind turbine generator sets are connected in a direct current power transmission grid-connected system in a series-parallel mode or a parallel-series mode through a centralized DC-DC converter to transmit electric energy to a land electric power system, the offshore wind power direct current power transmission system is high in voltage level, and the voltage level of the centralized DC-DC converter is consistent with that of the direct current power transmission grid-connected system, so that the centralized DC-DC converter is high in technical implementation difficulty and equipment cost, popularization and application of an offshore wind power full direct current grid-connected technology are restricted, and popularization and application of an offshore wind power direct current collection technology are restricted.
SUMMERY OF THE UTILITY MODEL
An object of the utility model is to provide an offshore wind power alternating current direct current network deployment system has solved and has adopted centralized DC-DC transverter technical realization degree of difficulty when matcing offshore wind power direct current transmission system high voltage level at present big, problem with high costs.
The utility model discloses a realize through following technical scheme:
an offshore wind power alternating current and direct current networking system comprises an offshore wind power direct current collection module and a centralized DC-AC current conversion module; the centralized DC-AC converter module comprises a centralized DC-AC converter and an isolation transformer;
the centralized DC-AC converter is connected with a direct current output port of the offshore wind power direct current collection module and is used for converting direct current of the offshore wind power direct current collection module into alternating current; the isolation transformer is connected with the centralized DC-AC converter and used for boosting the alternating current output by the centralized DC-AC converter to form high-voltage alternating current.
Further, the centralized DC-AC converter adopts a three-phase MMC converter or a single-phase MMC converter.
Furthermore, an MMC submodule in the three-phase MMC converter or the single-phase MMC converter adopts a half-bridge submodule structure, a full-bridge submodule structure or a clamping submodule structure.
Furthermore, a medium-voltage side port of the isolation transformer is connected with an alternating current output port of the centralized DC-AC converter, and a high-voltage side port is used as a high-voltage alternating current output port.
Further, the isolation transformer is grounded at a high-voltage side neutral point or a medium-voltage side neutral point.
Further, the isolation transformer is a three-phase transformer or a single-phase transformer.
Furthermore, the high-voltage side port of the isolation transformer is connected with the onshore transformer substation through an alternating current submarine cable.
Furthermore, a high-voltage side port of the isolation transformer is connected with the onshore converter station through the flexible direct-current transmission offshore converter station and the direct-current submarine cable in sequence.
Furthermore, the offshore wind power direct current collection module comprises a plurality of direct current wind power generation sets, and each direct current wind power generation set comprises a wind driven generator, an AC-DC rectifier and a DC-DC converter which are connected in sequence.
Compared with the prior art, the utility model discloses following profitable technological effect has:
the utility model discloses an offshore wind power AC-DC networking system, which comprises an offshore wind power DC collection module and a centralized DC-AC current conversion module, wherein the centralized DC-AC current conversion module comprises a centralized DC-AC current converter and an isolation transformer; the centralized DC-AC converter is connected with a direct current output port of the offshore wind power direct current collection module, converts direct current of the offshore wind power direct current collection module into alternating current, and boosts the alternating current through the isolation transformer to form a high-voltage alternating current output port. The alternating current output port can directly adopt an alternating current submarine cable to transmit electric energy to a land transformer substation, and can also be connected to a flexible direct current transmission offshore converter station, and the electric energy is transmitted to the land converter station through a flexible direct current transmission system. The utility model discloses do not adopt the DC-DC transverter of the high voltage class of full direct current network deployment system, but collect the module with marine wind power direct current and produce the output port of interchange through centralized DC-AC transverter transform, carry out interchange through isolation transformer and step up, reduced the high voltage class of centralized DC-AC transverter, improved the technical economy nature of system on the whole. The utility model is suitable for an offshore wind power system based on direct current collects the scene that the technique adopted alternating current transmission to be incorporated into the power networks to send out or adopted flexible direct current transmission to be incorporated into the power networks to send out; the grid-connected sending-out difficulty and the engineering cost of the offshore wind power system adopting the direct current collection technology can be reduced.
Furthermore, the isolation transformer is grounded at a high-voltage side or a medium-voltage side, so that the stability of the ground insulation of the offshore wind power full-direct-current networking system is ensured.
Drawings
Fig. 1 is a structural diagram of an offshore wind power alternating current and direct current grid-connected system based on alternating current transmission grid connection.
Fig. 2 is a block diagram of a centralized DC-AC conversion module.
FIG. 3 is a structure diagram of an offshore wind power AC/DC grid-connected system based on flexible DC power transmission grid connection;
the system comprises an offshore wind power direct current collection module 1, a centralized DC-AC converter module 2, a land transformer substation 3, an alternating current submarine cable 4, a flexible direct current transmission offshore converter station 5, a direct current submarine cable 6 and a land converter station 7, wherein the offshore wind power direct current collection module is arranged on the sea;
11 is a wind driven generator, 12 is an AC-DC rectifier, 13 is a DC-DC converter, and 14 is a direct current output port;
21 is a centralized DC-AC converter, and 22 is an isolation transformer;
211 is an MMC sub-module, 221 is a medium pressure side port, and 222 is a high pressure side port.
Detailed Description
The present invention will now be described in further detail with reference to specific examples, which are intended to be illustrative, but not limiting, of the invention.
Example 1
As shown in fig. 1, the utility model discloses an offshore wind power alternating current and direct current network deployment system based on alternating current transmission is incorporated into power networks contains offshore wind power direct current and collects module 1, centralized DC-AC current conversion module 2, high-voltage alternating current submarine cable 4 and land transformer substation 3.
The offshore wind power direct current collection module 1 comprises a plurality of direct current wind power generation sets, each direct current wind power generation set comprises a wind driven generator 11, an AC-DC rectifier 12 and a DC-DC converter 13, and the wind driven generator 11 outputs three-phase alternating current, then the three-phase alternating current passes through the AC-DC rectifier 12 and then passes through the DC-DC converter 13 to output direct current electric energy.
The topological structure of the DC-DC converter 13 of the direct current wind turbine generator set is an isolated DC-DC converter 13.
The offshore wind power direct current collection module 1 is formed by connecting the direct current outlet sides of a plurality of direct current wind power units in series-parallel to form the offshore wind power direct current collection module 1, and a direct current output port 14 of the direct current collection module is formed.
In addition to the form of the dc collection module of the "series-parallel" structure shown in fig. 1, the offshore wind power dc collection module 1 may also form a dc collection module by "series", "parallel", or "parallel-series" on the dc outlet side of a plurality of dc wind power generation sets.
The centralized DC-AC converter module 2 is connected with a DC output port 14 of the DC collection module, converts the DC of the offshore wind power DC collection module 1 into AC with a suitable voltage level, and transmits the electric energy to the onshore transformer substation 3 through the AC submarine cable 4. The offshore wind power with the short power transmission distance is more economical in a high-voltage alternating-current power transmission mode than a flexible direct-current power transmission mode, and the problem that the offshore wind power collected by direct current and with the short power transmission distance is sent out through alternating-current power transmission can be solved.
As shown in fig. 1, the centralized DC-AC converter module 2 includes a centralized DC-AC converter 21 and an isolation transformer 22.
The centralized DC-AC converter 21 is connected with the DC output port 14 of the offshore wind power DC collection module 1 and adopts a three-phase MMC converter structure or a single-phase MMC converter structure.
As shown in fig. 2, in the three-phase MMC current converter and the single-phase MMC current converter, the MMC submodule 211 may adopt a half-bridge submodule structure, or may also adopt a full-bridge submodule structure and a clamping submodule structure.
The isolation transformer 22 is a three-phase or single-phase transformer, wherein the voltage side of the isolation transformer is connected with the AC output port of the centralized DC-AC converter 21, and a high-voltage AC output port is formed after AC boosting.
The isolation transformer 22 is grounded on a high-voltage side or a medium-voltage side, so that the stability of the ground insulation of the offshore wind power full-direct-current networking system is ensured.
Example 2
As shown in fig. 3, the utility model discloses an offshore wind power AC/DC networking system based on flexible direct current transmission is incorporated into power networks contains offshore wind power direct current and collects module 1, centralized DC-AC current conversion module 2, flexible direct current transmission offshore converter station 5, direct current submarine cable 6 and flexible direct current transmission's onshore current conversion station 7. The offshore wind power direct current collection module 1 and the centralized DC-AC conversion module 2 in the embodiment are the same as those in the embodiment 1.
The offshore wind power with a longer power transmission distance has higher economical efficiency by adopting a flexible direct current power transmission mode than a high-voltage alternating current power transmission mode. The embodiment aims at a system that offshore wind power collected by alternating current is adopted in a main area of an offshore wind farm and is transmitted by flexible direct current transmission, and an offshore wind farm in a partial area adopts a direct current collection mode. The offshore wind power collection system is connected to the flexible direct current transmission offshore converter station 5 through the centralized DC-AC converter module 2, and offshore wind power in a direct current collection mode is sent out through the flexible direct current transmission system, so that the engineering demonstration difficulty and economic cost of the offshore wind power direct current collection technology in a long-distance transmission scene are reduced.
The centralized DC-AC converter module 2 is connected with the DC output port 14 of the DC collection module, converts the DC of the offshore wind power DC collection module 1 into AC with a suitable voltage level, is connected to the flexible DC transmission offshore converter station 5 through the high-voltage side output port of the isolation transformer 22, and transmits the electric energy to the flexible DC transmission onshore converter station 7 through the DC submarine cable 6.
Finally, it should be noted that: the above embodiments are only used for illustrating the technical solutions of the present application and not for limiting the scope of protection thereof, and although the present application is described in detail with reference to the above embodiments, those of ordinary skill in the art should understand that: numerous variations, modifications, and equivalents will occur to those skilled in the art upon reading the present application and are intended to be within the scope of the claims appended hereto.

Claims (9)

1. An offshore wind power alternating current and direct current networking system is characterized by comprising an offshore wind power direct current collection module (1) and a centralized DC-AC conversion module (2); the centralized DC-AC converter module (2) comprises a centralized DC-AC converter (21) and an isolation transformer (22);
the centralized DC-AC converter (21) is connected with a direct current output port (14) of the offshore wind power direct current collection module (1) and is used for converting direct current of the offshore wind power direct current collection module (1) into alternating current; the isolation transformer (22) is connected with the centralized DC-AC converter (21) and is used for boosting the alternating current output by the centralized DC-AC converter (21) to form high-voltage alternating current.
2. An offshore wind power AC-DC networking system according to claim 1, characterized in that the centralized DC-AC converter (21) is a three-phase MMC converter or a single-phase MMC converter.
3. An offshore wind power AC-DC networking system according to claim 2, characterized in that the MMC sub-module (211) in the three-phase MMC converter or the single-phase MMC converter is of a half-bridge sub-module structure, a full-bridge sub-module structure or a clamping double sub-module structure.
4. An offshore wind power AC-DC networking system according to claim 1, characterized in that the medium voltage side port (221) of the isolation transformer (22) is connected with the AC output port of the centralized DC-AC converter (21) and the high voltage side port (222) is used as the high voltage AC output port.
5. An offshore wind power AC/DC networking system according to claim 1, characterized in that the isolation transformer (22) is earthed at the high or medium voltage side neutral point.
6. An offshore wind power AC-DC networking system according to claim 1, characterized in that the isolation transformer (22) is a three-phase transformer or a single-phase transformer.
7. An offshore wind power AC/DC networking system according to claim 1, characterized in that the high voltage side ports (222) of the isolation transformers (22) are connected to the onshore substation (3) by means of an AC subsea cable (4).
8. An offshore wind power AC/DC networking system according to claim 1, characterized in that the high voltage side port (222) of the isolation transformer (22) is connected to the onshore converter station (7) via the flexible DC power transmission offshore converter station (5) and the DC submarine cable (6) in sequence.
9. An offshore wind power AC-DC networking system according to any one of claims 1 to 8, characterized in that the offshore wind power DC collection module (1) comprises a plurality of DC wind power generation sets, and each DC wind power generation set comprises a wind power generator (11), an AC-DC rectifier (12) and a DC-DC converter (13) which are connected in sequence.
CN202121280529.5U 2021-06-08 2021-06-08 Offshore wind power alternating current and direct current networking system Active CN214850510U (en)

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Application Number Priority Date Filing Date Title
CN202121280529.5U CN214850510U (en) 2021-06-08 2021-06-08 Offshore wind power alternating current and direct current networking system

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202121280529.5U CN214850510U (en) 2021-06-08 2021-06-08 Offshore wind power alternating current and direct current networking system

Publications (1)

Publication Number Publication Date
CN214850510U true CN214850510U (en) 2021-11-23

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Country Status (1)

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