CN112886639A

CN112886639A - Offshore wind power transmission system

Info

Publication number: CN112886639A
Application number: CN202110195301.4A
Authority: CN
Inventors: 詹长江; 邵震霞; 于海波; 张晓波; 张宝顺; 董云龙
Original assignee: NR Electric Co Ltd; NR Engineering Co Ltd
Current assignee: NR Electric Co Ltd; NR Engineering Co Ltd
Priority date: 2021-02-20
Filing date: 2021-02-20
Publication date: 2021-06-01

Abstract

The application provides an offshore wind power transmission system, includes: the wind driven generator tower is arranged in the sea; the wind driven generator main machine is arranged on the wind driven generator tower; the wind driven generator step-up transformer is electrically connected with the wind driven generator main machine; the first alternating current circuit is electrically connected to the tower of the wind driven generator; the current collection platform is electrically connected with the boosting transformer of the wind driven generator through a first alternating current circuit; the second alternating current circuit is electrically connected with the current collection platform; and the land transformer is electrically connected with the current collection platform through a second alternating current line, wherein all or part of the first alternating current line and/or the second alternating current line adopts a three-phase alternating current overhead line. According to the technical scheme of the application, the problem of capacitance and current caused by submarine cables is solved by adopting a three-phase alternating current overhead line mode, so that reactive compensation equipment at the two ends of the sea and the land is saved. The integrated design of the current collection platform and the fan furthest utilizes fan facilities, saves the investment of an offshore platform and is more environment-friendly.

Description

Offshore wind power transmission system

Technical Field

The application relates to the technical field of power transmission of power systems, in particular to an offshore wind power transmission system.

Background

At present, electric energy of an offshore wind farm is mainly transmitted to inland through two transmission modes, one mode is high-voltage alternating current submarine cable transmission, and the other mode is flexible direct current transmission. The latter is mainly applied to open sea wind farms, while the former is mainly applied to offshore wind farms. The high-voltage alternating-current submarine cable power transmission has the advantages of mature technology and good economy, but as the distributed capacitance of a cable line is far larger than that of an overhead line, the generated capacitance current can obviously reduce the transmission capability of the cable, and the power transmission capability of the cable rapidly decreases along with the increase of the power transmission distance.

Disclosure of Invention

The application provides an offshore wind power transmission system, can make full use of existing fan facilities to the overhead line is transmission medium, furthest reduces engineering equipment and construction cost when promoting transmission capacity.

The features and advantages of the power transmission system of the present application will become apparent from the following detailed description, or may be learned in part by the practice of the present application.

According to an aspect of the present application, there is provided an offshore wind power transmission system, comprising: the wind driven generator tower is arranged in the sea; the wind driven generator main machine is arranged on the wind driven generator tower; the wind driven generator step-up transformer is electrically connected with the wind driven generator main machine; the first alternating current circuit is electrically connected to the tower of the wind driven generator; the current collection platform is electrically connected with the boosting transformer of the wind driven generator through a first alternating current circuit; the second alternating current circuit is electrically connected with the current collection platform; and the land transformer is electrically connected with the current collection platform through the second alternating current line, wherein all or part of the first alternating current line and/or the second alternating current line adopts a three-phase alternating current overhead line.

According to some embodiments, the collection platform comprises a collection busbar and a collection step-up transformer.

According to some embodiments, the current collection platform is independently constructed at sea.

According to some embodiments, at least one first ac overhead line tower is provided between the collecting platform and the wind turbine step-up transformer for carrying the first ac line.

According to some embodiments, at least one second ac overhead line tower is provided between the power collection platform and the land transformer for carrying the second ac line.

According to some embodiments, the current collection platform is located on the wind turbine tower.

According to some embodiments, the first ac line comprises a subsea ac cable.

According to some embodiments, the second ac line comprises a subsea ac cable.

According to some embodiments, the offshore wind power transmission system further comprises: a current collection platform to which the wind turbine step-up transformer is connected via the first ac line through the sub current collection platform.

According to some embodiments, the first ac line is mounted on a wind turbine tower.

According to some embodiments, by using overhead lines, the problem of capacitive current due to submarine cables is avoided, thereby eliminating reactive compensation equipment at both the sea and the land.

According to the embodiment of the application, the problem of capacitance and current caused by submarine cables is solved by adopting a three-phase alternating current overhead line mode, so that reactive compensation equipment at the two ends of the sea and the land is saved. The integrated design of the current collection platform and the fan furthest utilizes fan facilities, saves the investment of an offshore platform and is more environment-friendly.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the application.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without exceeding the protection scope of the present application.

Fig. 1 shows a block diagram of a typical existing offshore wind power high voltage ac submarine cable power transmission system according to an exemplary embodiment.

Fig. 2 shows a schematic diagram of an offshore wind power transmission system according to an exemplary embodiment.

Fig. 3 shows a schematic diagram of an offshore wind power transmission system according to another exemplary embodiment.

Detailed Description

Example embodiments will now be described more fully with reference to the accompanying drawings. Example embodiments may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the concept of example embodiments to those skilled in the art. The same reference numerals denote the same or similar parts in the drawings, and thus, a repetitive description thereof will be omitted.

The described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. In the following description, numerous specific details are provided to give a thorough understanding of embodiments of the disclosure. One skilled in the relevant art will recognize, however, that the embodiments of the disclosure can be practiced without one or more of the specific details, or with other means, components, materials, devices, or the like. In such cases, well-known structures, methods, devices, implementations, materials, or operations are not shown or described in detail.

Furthermore, the terms "include" and "have," as well as any variations thereof, are intended to cover non-exclusive inclusions. For example, a process, method, system, article, or apparatus that comprises a list of steps or elements is not limited to only those steps or elements listed, but may alternatively include other steps or elements not listed, or inherent to such process, method, article, or apparatus.

The terms "first," "second," and the like in the description and claims of the present application and in the above-described drawings are used for distinguishing between different objects and not for describing a particular order. Furthermore, the terms "include" and "have," as well as any variations thereof, are intended to cover non-exclusive inclusions.

Fig. 1 shows a block diagram of a typical offshore wind power high voltage ac submarine cable power transmission system according to an exemplary embodiment.

As shown in fig. 1, according to the embodiment, the distributed offshore wind turbine (wind turbine) is connected to a collection system bus 103 on an offshore platform 106 through a first step-up transformer 101 and a submarine cable 102, then is transmitted to land through a second step-up transformer 105 and a remote submarine cable 107, and is connected to an ac power grid after being stepped up or down on land through a transformer 108. Reactive compensation equipment 104a and 104b is provided both on the offshore platform and on land to compensate for reactive currents in the submarine cable. Typically, a first step-up transformer 101 is installed in the wind turbine tower, an offshore platform 106 is installed separately in the sea, on which a collector system bus 103, a second step-up transformer 105 and reactive compensation equipment 104a are arranged.

According to the embodiment, the

remote submarine cables

102 and 107 mainly include oil-filled insulated submarine cables and extruded plastic insulated submarine cables from the viewpoint of insulation composition, and the oil-filled submarine cables are high in maintenance cost and not environment-friendly; the extruded plastic insulated submarine cable has the advantages of light weight, relatively friendly environment, easy production and simple maintenance. From the aspect of load types, the direct current submarine cable is divided into a direct current submarine cable and an alternating current submarine cable, the direct current submarine cable is characterized by low loss and easy realization of long-distance power transmission, but the cost of the matched construction of a direct current converter station and the like corresponding to the direct current submarine cable is high; the loss of the alternating current submarine cable is large, but the operation and maintenance technology is mature compared with the direct current submarine cable, and the supporting construction cost is low.

According to the embodiment, the reactive compensation devices 104a and 104b perform centralized compensation in the substation aiming at the reactive balance of the power grid, and the reactive compensation devices 104a and 104b comprise parallel capacitors, synchronous phase modulators, static compensators and the like, and mainly aim at balancing the reactive power of the power grid, improving the power factor of the power grid, improving the bus voltage of a system terminal substation, and compensating the reactive loss of a main transformer of the substation and a high-voltage transmission line. These compensation devices are generally centralized on the 10kV bus of the transformer substation, and the disadvantage is that the compensation mode does not work on the loss reduction of the 10kV distribution network.

According to the embodiment, the reactive compensation of the line is realized by installing a capacitor on a line tower, and the number of line compensation points is not too large; the control mode is simple, and generally, the grouping switching control is not adopted; the compensation capacity is not too large, and the phenomenon of over-compensation is avoided. The line compensation mode mainly provides reactive power needed by the line and the public transformer, and is suitable for long lines with low power factor and heavy load. The defects are that the adaptability is poor, the compensation is insufficient under the condition of heavy load, and the like.

As shown in fig. 2, according to an embodiment, the distributed wind turbine of the present application is composed of a wind turbine main unit 201, a wind turbine tower 202, and a wind turbine step-up transformer 203, wherein the wind turbine main unit 201 is located on the wind turbine tower 202, and is connected to a current collection bus 206 located on a current collection platform 205 through a wind turbine step-up transformer 1 203 and a first ac line 204, and is transported to land through a current collection step-up transformer 207 and a second ac line 208, and is connected to an ac grid after being stepped up or stepped down on land through a transformer 210.

According to an embodiment, the first ac line 204 may be a three-phase ac overhead line, and may be mounted on the wind turbine tower 202; and a submarine alternating current cable can be adopted and selected according to the actual situation of the sea area.

According to the embodiment, the current collection platform 205 can be positioned on the tower 202 of the wind driven generator, and the integrated design is adopted, so that the equipment and construction cost can be reduced to the maximum extent; or may be located independently of the sea.

The ac line 208 connecting the power collection platform 205 and the land transformer 210 may be a three-phase ac overhead line or a subsea ac cable, and is selected according to the actual conditions in the sea area.

At least one ac overhead line tower 209 may be disposed between the power collection platform 205 and the onshore transformer 210 to transmit the electrical energy from the wind farm to the land.

As shown in fig. 3, in an offshore wind farm consisting of a plurality of offshore wind turbines 301, according to embodiments, may be pooled to one collection platform 310 or to a plurality of wind turbine sub-collection platforms such as 310 and 311, respectively. Specifically, the

distributed fans

301, 302, 303, 304, and 305 are firstly collected to the subset power station 310, then connected to the total collection platform 320 via the first ac line 204 through the three-phase ac overhead lines, and finally transported to the land via the second ac line 208, where they are boosted or stepped down by the transformer 210 and then connected to the ac grid; at least one ac overhead line tower 209 may be disposed between the collection platform 320 and the onshore transformer 210 to transmit the electrical energy from the wind farm to the land.

Alternatively, the sub-set level stations 310, 321 or the collective platform 320 may be constructed separately from offshore platforms installed in the sea.

Alternatively, some of the ac connection lines in the system, such as the first ac line 204 and the second ac line 208, may be replaced by subsea ac cables.

Optionally, at least one ac overhead line tower 209 is provided between the sub-set level station 310 and the wind turbine step-up transformer (not shown in fig. 3) for carrying the first ac line 204.

The foregoing detailed description of the embodiments of the present application has been presented to illustrate the principles and implementations of the present application, and the description of the embodiments is only intended to facilitate the understanding of the methods and their core concepts of the present application. Meanwhile, a person skilled in the art should, according to the idea of the present application, change or modify the embodiments and applications of the present application based on the scope of the present application. In view of the above, the description should not be taken as limiting the application.

Claims

1. An offshore wind power transmission system, comprising:

the wind driven generator tower is arranged in the sea;

the wind driven generator main machine is arranged on the wind driven generator tower;

the wind driven generator step-up transformer is electrically connected with the wind driven generator main machine;

the first alternating current circuit is electrically connected to the tower of the wind driven generator;

the current collection platform is electrically connected with the boosting transformer of the wind driven generator through a first alternating current circuit;

the second alternating current circuit is electrically connected with the current collection platform;

a land transformer electrically connected to the current collection platform via the second AC line,

wherein, the first AC line and/or the second AC line adopts three-phase AC overhead lines wholly or partially.

2. Offshore wind power transmission system according to claim 1, characterized in that the collection platform comprises a collection busbar and a collection step-up transformer.

3. Offshore wind power transmission system according to claim 1, characterized in that the collection platform is independently built at sea.

4. Offshore wind power transmission system according to claim 1, wherein at least one first ac overhead line tower is arranged between the collection platform and the wind turbine step-up transformer for carrying the first ac line.

5. Offshore wind power transmission system according to claim 1, wherein between the collection platform and the land transformer at least one second ac overhead line tower is arranged for carrying the second ac line.

6. Offshore wind power transmission system according to claim 1, wherein the power collection platform is located on the wind turbine tower.

7. Offshore wind power transmission system according to claim 1, characterized in that the first ac line comprises a subsea ac cable.

8. Offshore wind power transmission system according to claim 1, characterized in that the second ac line comprises a subsea ac cable.

9. Offshore wind power transmission system according to claim 1, further comprising:

a sub-collection platform through which the wind turbine step-up transformer is connected to the collection platform via the first ac line.

10. Offshore wind power transmission system according to claim 1, wherein the first ac line is mounted on a wind turbine tower.