Offshore wind power delivery system and method

Abstract

The invention relates to an offshore wind power delivery system and method. Relates to the power transmission field. The system at least comprises a wind power plant group, a booster station group, a transformation equipment group and a confluence power distribution device which are electrically connected in sequence, wherein the wind power plant group and the booster station group are located on the sea; the transformation equipment group and the confluence power distribution device are located inland; the wind power plant group at least comprises a first-class wind power plant and a second-class wind power plant, and the booster station group at least comprises a first-class booster station electrically connected with the first-class wind power plant and a second-class booster station electrically connected with the second-class wind power plant. The transformation device group at least comprises a first type of transformation device electrically connected with the first type of booster station and a second type of transformation device electrically connected with the second type of booster station; and the confluence power distribution device adopts 3 / 2 circuit breaker wiring and is used for sending out the received electric energy output by at least one of the first type of transformation equipment and the second type of transformation equipment. By adopting the system method, the power transmission efficiency of the offshore wind power delivery system can be improved.

Description

Technical Field

[0001] The present application relates to the technical field of power transmission, and particularly to an offshore wind power transmission system and method. Background Art

[0002] In modern power systems, wind energy, as a renewable energy source, has many advantages. Due to the high density and relative stability of offshore wind energy resources, offshore wind power transmission has gradually entered the stage of large-scale development. How to efficiently transmit offshore wind power has become a problem to be studied.

[0003] Currently, the methods for transmitting power using offshore wind energy include conventional high-voltage AC power transmission, flexible high-voltage DC power transmission, and low-frequency AC power transmission. However, the above methods are relatively single. In practical applications, for variable electric field conditions, they cannot simultaneously meet various types of offshore wind power transmission, affecting the power transmission efficiency. Therefore, the current offshore wind power transmission system has the problem of low power transmission efficiency. Summary of the Invention

[0004] Based on this, in view of the technical problem of low power transmission efficiency of the above-mentioned wind power transmission system, it is necessary to provide an offshore wind power transmission system and method.

[0005] In a first aspect, the present application provides an offshore wind power transmission system, which at least includes a wind farm group, a booster station group, a voltage conversion equipment group, and a busbar and distribution device that are electrically connected in sequence; wherein, the wind farm group and the booster station group are located offshore; the voltage conversion equipment group and the busbar and distribution device are located inland;

[0006] The wind farm group at least includes a first type of wind farm and a second type of wind farm, the booster station group at least includes a first type of booster station electrically connected to the first type of wind farm, and a second type of booster station electrically connected to the second type of wind farm, and the voltage conversion equipment group at least includes a first type of voltage conversion equipment electrically connected to the first type of booster station, and a second type of voltage conversion equipment electrically connected to the second type of booster station;

[0007] The busbar and distribution device adopts a 3 / 2 breaker connection to send out the electric energy received from at least one of the first type of voltage conversion equipment and the second type of voltage conversion equipment.

[0008] In one embodiment, the first type of booster station includes any one of a flexible DC offshore converter station, an offshore power frequency booster station, and an offshore low-frequency booster station; and the second type of booster station includes the other one of the flexible DC offshore converter station, the offshore power frequency booster station, and the offshore low-frequency booster station; the first type of voltage conversion equipment includes any one of a flexible DC converter, an AC switch, a booster device, and a frequency conversion device; the second type of voltage conversion equipment includes the other one of the flexible DC converter, the AC switch, the booster device, and the frequency conversion device.

[0009] In one embodiment, the flexible DC offshore converter station is electrically connected to the flexible DC converter via a DC submarine cable; the offshore power frequency step-up substation is electrically connected to at least one of the AC switch and the step-up equipment via a first AC submarine cable; the offshore low-frequency step-up substation is electrically connected to the frequency conversion equipment via a second AC submarine cable.

[0010] In one embodiment, a symmetric monopole connection is adopted between the flexible DC offshore converter station and the flexible DC converter, and the DC submarine cable has a first length; a line-transformer bank connection is adopted between the offshore power frequency step-up substation and the AC switch or the step-up equipment; the first AC submarine cable has a second length; a line-transformer bank connection is adopted between the offshore low-frequency step-up substation and the frequency conversion equipment; the second AC submarine cable has a third length; wherein, the first length is greater than the third length, and the third length is greater than the second length.

[0011] In one embodiment, the frequency conversion equipment adopts an M3C topology structure and is used to adjust at least one of the voltage and the harmonic content.

[0012] In one embodiment, the first type of wind farm is electrically connected to the first type of step-up substation via a collector line, and the second type of wind farm is electrically connected to the second type of step-up substation via a collector line; a single-bus sectionalized connection is adopted at the collector line junction; one of the first type of wind farm and the second type of wind farm includes a low-frequency wind farm.

[0013] In one embodiment, the busbar distribution device includes a first busbar, a second busbar, a plurality of circuit breaker units, a station service transformer, an energy storage system, and a filter circuit; wherein, each of the circuit breaker units includes 3 connected circuit breakers, and at least 4 of the circuit breaker units are connected between the first busbar and the second busbar; any one of the station service transformer, the energy storage system, and the filter circuit is connected to any one of the circuit breaker units.

[0014] In one embodiment, the output end of the transformer equipment group includes the first output end of the first type of transformer equipment and the second output end of the second type of transformer equipment; wherein, any output end of the transformer equipment group is connected to any one of the plurality of circuit breaker units, and the output end of the busbar distribution device is connected to another one of the plurality of circuit breaker units.

[0015] In one embodiment, the transformer equipment group and the busbar distribution device constitute an onshore offshore wind power collection station; the onshore offshore wind power collection station further includes auxiliary facilities, civil engineering, and buildings.

[0016] Second aspect, the present application provides a method for transmitting offshore wind power, the method comprising:

[0017] The input end of the busbar power distribution device is electrically connected to the transformer equipment group to collect the electric energy transmitted by the wind farm group to the transformer equipment group through the booster station group and send out the electric energy;

[0018] Wherein, the wind farm group and the booster station group are located offshore; the transformer equipment group and the busbar power distribution device are located inland;

[0019] The wind farm group includes at least a first type of wind farm and a second type of wind farm, the booster station group includes at least a first type of booster station electrically connected to the first type of wind farm and a second type of booster station electrically connected to the second type of wind farm, and the transformer equipment group includes at least a first type of transformer equipment electrically connected to the first type of booster station and a second type of transformer equipment electrically connected to the second type of booster station;

[0020] The busbar power distribution device adopts a 3 / 2 breaker connection to send out the electric energy output by at least one of the received first type of transformer equipment and the second type of transformer equipment.

[0021] The above offshore wind power transmission system at least includes a wind farm group, a booster station group, a transformer equipment group, and a busbar power distribution device that are electrically connected in sequence; wherein, the wind farm group and the booster station group are located offshore; the transformer equipment group and the busbar power distribution device are located inland; and the wind farm group includes at least a first type of wind farm and a second type of wind farm, the booster station group includes at least a first type of booster station electrically connected to the first type of wind farm and a second type of booster station electrically connected to the second type of wind farm, the transformer equipment group includes at least a first type of transformer equipment electrically connected to the first type of booster station and a second type of transformer equipment electrically connected to the second type of booster station; the busbar power distribution device adopts a 3 / 2 breaker connection to send out the electric energy output by at least one of the received first type of transformer equipment and the second type of transformer equipment. In the above system, by arranging the wind farm group and the booster station group offshore, the energy loss during power transmission can be effectively reduced, and the power utilization rate can be improved; and the reasonable allocation of the wind farm group and the booster station group offshore can achieve more optimized management and improve the reliability of the offshore wind power transmission system; in addition, the combination of different types of booster stations and transformer equipment can effectively cope with different load demands and supply changes; and the busbar power distribution device adopting a 3 / 2 breaker connection can improve the reliability of the overall system, thereby improving the power transmission efficiency of the offshore wind power transmission system. Description of the Drawings

[0022] To more clearly illustrate the technical solutions in the embodiments of the present application or the related art, the following will briefly introduce the drawings required for use in the description of the embodiments or the related art. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0023] Figure 1 It is a schematic diagram of an offshore wind power transmission system in an embodiment;

[0024] Figure 2 It is a schematic diagram of an offshore wind power transmission system in another embodiment;

[0025] Figure 3 It is a schematic diagram of the submarine cable connection relationship between a booster station group and a voltage transformation equipment group in an embodiment;

[0026] Figure 4 It is a schematic diagram of a busbar and distribution device in an embodiment;

[0027] Figure 5 It is a schematic diagram of an onshore transmission station in an embodiment;

[0028] Figure 6 It is a schematic diagram of an offshore wind power transmission system in yet another embodiment. Detailed implementation manners

[0029] To facilitate the understanding of the present application, the following will describe the present application more comprehensively with reference to the relevant drawings. Embodiments of the present application are given in the drawings. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present application more thorough and comprehensive.

[0030] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present application belongs. The terms used in the description of the present application in this specification are only for the purpose of describing specific embodiments and are not intended to limit the present application.

[0031] It can be understood that the terms "first", "second", etc. used in the present application can be used herein to describe various elements, but these elements are not limited by these terms. These terms are only used to distinguish one element from another. For example, without departing from the scope of the present application, a first type of wind farm can be called a second type of wind farm, and similarly, a second type of wind farm can be called a first type of wind farm. Both the first type of wind farm and the second type of wind farm are wind farms, but they are not the same wind farm.

[0032] It can be understood that for the "connection" in the following embodiments, if there is transmission of electrical signals or data between the connected circuits, modules, units, etc., it should be understood as "electrically connected", "communicatively connected", etc.

[0033] It can be understood that "at least one" means one or more, and "a plurality" means two or more. "At least part of an element" means part or all of the element.

[0034] As used herein, the singular forms "a", "an" and "the" may also include the plural forms unless the context clearly dictates otherwise. It should also be understood that the terms "comprise / include" or "have" etc. specify the presence of the stated features, wholes, steps, operations, components, parts or combinations thereof, but do not preclude the presence or addition of one or more other features, wholes, steps, operations, components, parts or combinations thereof. At the same time, the term "and / or" used in this specification includes any and all combinations of the related listed items.

[0035] In an exemplary embodiment, as Figure 1 shown, there is provided an offshore wind power transmission system 100, which at least includes a wind farm group 101, a booster station group 102, a voltage transformation equipment group 103 and a busbar and distribution device 104 that are electrically connected in sequence; wherein, the wind farm group 101 and the booster station group 102 are located offshore; the voltage transformation equipment group 103 and the busbar and distribution device 104 are located inland; the wind farm group 101 at least includes a first type of wind farm and a second type of wind farm, the booster station group 102 at least includes a first type of booster station electrically connected to the first type of wind farm and a second type of booster station electrically connected to the second type of wind farm, the voltage transformation equipment group 103 at least includes a first type of voltage transformation equipment electrically connected to the first type of booster station and a second type of voltage transformation equipment electrically connected to the second type of booster station; the busbar and distribution device 104 adopts a 3 / 2 breaker connection and is used to send out the electric energy output by at least one of the received first type of voltage transformation equipment and the second type of voltage transformation equipment.

[0036] Among them, the offshore wind power transmission system refers to the system that transmits the electric energy generated by offshore wind power generation to the onshore power grid, mainly used to achieve efficient wind energy conversion and power transmission; the wind farm group 101 refers to a wind farm group composed of multiple different types of wind farms; the booster station group 102 is a group of devices that convert the electric energy generated by the wind farm into the form of electric energy to be transmitted to the transformer equipment group 103; the transformer equipment group 103 is located inland and converts the electric energy input by the booster station group 102 into the form of electric energy suitable for entering the busbar distribution device 104; the busbar distribution device 104 refers to the device that integrates power sources and distributes electric energy; the 3 / 2 breaker connection refers to an electrical connection method that can achieve flexible switching between different power sources and allows the selection of electric energy output from multiple transformer devices; and the busbar distribution device 104 can be a 500 kV busbar distribution device.

[0037] Furthermore, the wind farm group 101 can include, for example, small wind farms, large wind farms, steady-state wind farms, and fluctuating wind farms, etc.; the first type of wind farm and the second type of wind farm refer to the types of wind farms; the booster station group 102 can include the first type of booster station electrically connected to the first type of wind farm and the second type of booster station electrically connected to the second type of wind farm, used to ensure the smooth transmission of electric power between different types of wind farms; the transformer equipment group 103 can at least include the first type of transformer equipment connected to the first type of booster station and the second type of transformer equipment connected to the second type of booster station; the 3 / 2 breaker connection can simultaneously monitor three different inputs, such as the electric energy from different transformer devices, and select two of the output power sources through control logic to send the electric energy into the busbar distribution device 104.

[0038] Further, the wind farm group 101 can also include the third type of wind farm, etc., and the booster station group 102 can also include the third type of booster station, etc.; the transformer equipment group 103 can also include the third type of transformer equipment electrically connected to the third type of booster station, etc.

[0039] In the above-mentioned offshore wind power transmission system, it at least includes a wind farm group 101, a booster station group 102, a voltage transformation equipment group 103 and a busbar distribution device 104 that are electrically connected in sequence; among them, the wind farm group 101 and the booster station group 102 are located offshore; the voltage transformation equipment group 103 and the busbar distribution device 104 are located inland; and the wind farm group 101 at least includes a first type of wind farm and a second type of wind farm, the booster station group 102 at least includes a first type of booster station electrically connected to the first type of wind farm, and a second type of booster station electrically connected to the second type of wind farm, the voltage transformation equipment group 103 at least includes a first type of voltage transformation equipment electrically connected to the first type of booster station, and a second type of voltage transformation equipment electrically connected to the second type of booster station; the busbar distribution device 104 adopts a 3 / 2 breaker connection to send out the electric energy received from at least one of the first type of voltage transformation equipment and the second type of voltage transformation equipment. In the above system, by setting the wind farm group 101 and the booster station group 102 offshore, the energy loss during power transmission can be effectively reduced, and the power utilization rate can be improved; and the reasonable distribution of the wind farm group 101 and the booster station group 102 offshore can achieve more optimized management and improve the reliability of the offshore wind power transmission system; in addition, the combination of different types of booster stations and voltage transformation equipment can effectively cope with different load demands and supply changes; and the busbar distribution device 104 adopting a 3 / 2 breaker connection can improve the reliability of the overall system, thereby improving the power transmission efficiency of the offshore wind power transmission system.

[0040] In an exemplary embodiment, the first type of booster station includes any one of a flexible DC offshore converter station, an offshore power frequency booster station, and an offshore low-frequency booster station; and the second type of booster station includes another one of a flexible DC offshore converter station, an offshore power frequency booster station, and an offshore low-frequency booster station; the first type of voltage transformation equipment includes any one of a flexible DC converter, an AC switch, a boosting device, and a frequency conversion device; the second type of voltage transformation equipment includes another one of a flexible DC converter, an AC switch, a boosting device, and a frequency conversion device.

[0041] Among them, the flexible DC offshore converter station refers to a booster station for converting the power generated by offshore wind power; the offshore power frequency booster station refers to a booster station that boosts the alternating current of power frequency, such as 50Hz or 60Hz, to a higher voltage through a transformer; the offshore low-frequency booster station refers to a booster station that can boost low-frequency power (frequency below 50HZ) to provide electric energy for specific equipment or systems; the flexible DC converter refers to a voltage transformation equipment for AC / DC power conversion and regulation; the AC switch refers to a voltage transformation equipment for controlling the power flow, which can switch the circuit and cut off or connect the power supply; the boosting device refers to a boosting device that boosts the voltage through a transformer; the frequency conversion device refers to a voltage transformation equipment for changing the frequency of power.

[0042] In addition, it should be noted that the flexible DC offshore converter station, the offshore power frequency step-up station, and the offshore low-frequency step-up station in the step-up station group in the above embodiments correspond one-to-one with the flexible DC converter, the AC switch, the step-up equipment, and the frequency conversion equipment in the voltage conversion equipment group.

[0043] As an example, as Figure 2 shown, the first type of step-up station is a flexible DC offshore converter station, and the second type of step-up station is an offshore low-frequency step-up station; the first type of voltage conversion equipment is a flexible DC converter, and the second type of voltage conversion equipment is a frequency conversion equipment.

[0044] In this embodiment, by simultaneously selecting the first type of step-up station and the second type of step-up station, as well as the step-up equipment corresponding to the first type of step-up station and the second type of step-up station, the reliability of the system is improved, and the power supply interruption caused by the failure of a single type of equipment is avoided, thereby ensuring that the offshore wind power transmission system can efficiently and safely transmit electrical energy.

[0045] In one embodiment, as Figure 3 shown, the flexible DC offshore converter station is electrically connected to the flexible DC converter through a DC submarine cable; the offshore power frequency step-up station is electrically connected to at least one of the AC switch and the step-up equipment through a first AC submarine cable; the offshore low-frequency step-up station is electrically connected to the frequency conversion equipment through a second AC submarine cable.

[0046] Among them, the DC submarine cable refers to the cable used to connect the offshore converter station and the flexible DC converter, which is designed for DC power transmission, can withstand long-term current and voltage flow, and has high waterproof and corrosion resistance in deep water environments; the first AC submarine cable refers to the cable used for power transmission between the offshore power frequency step-up station and its supporting step-up equipment, such as the AC switch and the step-up equipment, which has the characteristics of high strength and strong anti-interference; the second AC submarine cable refers to the cable used to connect the offshore low-frequency step-up station and the frequency conversion equipment, which supports the transmission of low-frequency electrical energy and can ensure that the electrical energy is not affected by the environment when transmitted to the frequency conversion equipment.

[0047] In this embodiment, by matching reasonable cables for different step-up stations and voltage conversion equipment, it can ensure that each step-up station and voltage conversion equipment cooperate with each other in the offshore wind power project, ensuring the efficient transmission of electrical energy and the flexibility of the system; moreover, the connection method of each step-up station and voltage conversion equipment has its specific functions and characteristics, further ensuring the efficient operation of the entire offshore wind power transmission system.

[0048] Furthermore, in one embodiment, a symmetric monopolar connection is adopted between the flexible DC offshore converter station and the flexible DC converter, and the DC submarine cable has a first length; a line-transformer unit connection is adopted between the offshore power frequency step-up substation and the AC switch or step-up equipment; the first AC submarine cable has a second length; a line-transformer unit connection is adopted between the offshore low-frequency step-up substation and the frequency conversion equipment; the second AC submarine cable has a third length; wherein, the first length is greater than the third length, and the third length is greater than the second length.

[0049] Among them, the symmetric monopolar connection refers to the adoption of a monopolar connection configuration to ensure the coherence and stability of the current flow direction; submarine cables of different lengths correspond to different power transmission distances. And DC submarine cables usually adopt a monopolar or symmetric monopolar configuration, which is suitable for long-distance high-voltage DC power transmission and can significantly reduce power losses. AC submarine cables are suitable for AC power transmission systems and are suitable for regional power grids or short-distance power transmission.

[0050] As an example, since the first length of the DC submarine cable is greater than the third length of the second AC submarine cable, and the third length of the second AC submarine cable is greater than the second length of the first AC submarine cable, it can be shown that under the same other conditions, the flexible DC offshore converter station is suitable for long-distance power transmission, the offshore power frequency step-up substation is suitable for short-distance power transmission, and the offshore low-frequency step-up substation is suitable for medium-distance power transmission.

[0051] In this embodiment, through the design and configuration of different power equipment and connection methods in the offshore wind power system, the effective transmission and conversion of electric power are ensured; through submarine cables of different lengths and specific connection methods, the offshore wind power transmission system can flexibly respond to different power demands and operating conditions, improving the power transmission efficiency.

[0052] In one embodiment, the frequency conversion equipment adopts IGBT power electronic devices to convert low-frequency voltage into power frequency voltage.

[0053] Among them, IGBT (Insulated Gate Bipolar Transistor) has a high switching speed and a large current-carrying capacity; conversion refers to the process of changing low-frequency voltage into power frequency voltage through frequency conversion equipment, which usually involves voltage adjustment and frequency redefinition to ensure the compatibility and stability of the power supply system; therefore, since the offshore wind power output is low-frequency and becomes power frequency on land and in the power grid, it is necessary to convert it into power frequency electricity before connecting to the power grid.

[0054] Furthermore, in one embodiment, the first type of wind farm is electrically connected to the first type of step-up substation by a collector line, and the second type of wind farm is electrically connected to the second type of step-up substation by a collector line; a single busbar sectionalized connection is adopted at the collector line convergence; one of the first type of wind farm and the second type of wind farm includes a low-frequency wind farm.

[0055] Among them, the collector line refers to the power line used in a wind farm to converge the electricity generated by multiple wind turbines to a step-up substation, which can concentrate electrical energy, reduce transmission losses and improve the overall operation efficiency; the single-bus sectionalized connection refers to the electrical connection method of using a single bus for sectionalization at the convergence point of the collector line to ensure the flexibility and reliability of the offshore wind power transmission system. The reasons for choosing this connection method are as follows: the capacity of a single-circuit collector line sent to the step-up substation is limited, and even if it is lost, it does not affect the overall capacity transmission; the cost of the offshore platform is expensive, and using a single-bus connection can save the number of circuit breakers, save platform space and weight, so as to achieve the purpose of reducing the project cost; the low-frequency wind farm refers to a wind farm that produces electrical energy with a relatively low frequency.

[0056] In this embodiment, the first type of wind farm and the second type of wind farm are respectively connected to their corresponding step-up substations through collector lines, and the power is converged by using the single-bus sectionalized connection method, which can ensure the flexibility and reliability of the offshore wind power transmission system; at the same time, by designating one of the types of wind farms as a low-frequency wind farm, it provides strong support for the power transmission of different wind farms.

[0057] In one embodiment, as Figure 4 shown, the busbar and distribution device 104 includes a first busbar 401, a second busbar 402, a plurality of circuit breaker units 403, a station service transformer 404, an energy storage system 405, and a filter circuit 406; among them, each circuit breaker unit includes 3 connected circuit breakers, and at least 4 circuit breaker units are connected between the first busbar and the second busbar 402; any one of the station service transformer 404, the energy storage system 405, and the filter circuit is connected to any circuit breaker unit.

[0058] Among them, the first busbar 401 refers to the main conductive line in the busbar and distribution device 104, which is usually used to connect multiple power sources and loads; the second busbar 402 refers to the conductive line parallel or complementary to the first busbar 401; the plurality of circuit breaker units 403 refers to a kind of power protection device used to prevent problems such as damage to the power system caused by overload, short circuit and other faults, and three circuit breakers are connected to form a circuit breaker unit; the station service transformer 404 refers to the transformer that provides power for the internal system of the busbar and distribution device 104; the energy storage system 405 refers to the device used to store electrical energy; the filter (harmonic eliminator) circuit refers to the circuit that purifies the power signal and can reduce harmonics and other interferences.

[0059] Furthermore, the busbar and distribution device 104 further includes 500 kV AC transmission 1 and 500 kV AC transmission 2.

[0060] In this embodiment, the busbar power distribution device 104 effectively combines multiple circuit breaker units, a station service transformer 404, an energy storage system 405, and a filter circuit through a first busbar 401 and a second busbar 402 to form a stable and efficient system. Each component in the system plays an important role in optimizing power distribution, safety protection, and improving power quality, jointly ensuring the stable operation of the offshore wind power transmission system.

[0061] Furthermore, in one embodiment, the output end of the voltage transformation equipment group includes the first output end of the first type of voltage transformation equipment and the second output end of the second type of voltage transformation equipment; wherein, any output end of the voltage transformation equipment group is connected to any one of the multiple circuit breaker units 403, and the output end of the busbar power distribution device 104 is connected to another one of the multiple circuit breaker units 403.

[0062] As an example, the first output end of the first type of voltage transformation equipment included in the voltage transformation equipment group is connected to any circuit breaker in any one of the circuit breaker units in the busbar power distribution device, and the first output end of the busbar power distribution device corresponding to the first output end of the first type of voltage transformation equipment ( Figure 4 500 kV AC transmission 1 in), is connected to another circuit breaker in any one of the above-mentioned circuit breaker units; the second output end of the second type of voltage transformation equipment included in the voltage transformation equipment group is connected to any circuit breaker in another one of the circuit breaker units in the busbar power distribution device, and the second output end of the busbar power distribution device corresponding to the second output end of the second type of voltage transformation equipment ( Figure 4 500 kV AC transmission 2 in), is connected to another circuit breaker in another one of the above-mentioned circuit breaker units; therefore, the first output end and the second output end of the above-mentioned first type of voltage transformation equipment can be connected to any circuit breaker in different circuit breaker units; and the first output end and the second output end of the busbar power distribution device are also connected to another circuit breaker in the corresponding circuit breaker units.

[0063] As another example, the first output end of the first type of voltage transformation equipment included in the voltage transformation equipment group is connected to any circuit breaker in any one of the circuit breaker units in the busbar power distribution device; while the second output end of the second type of voltage transformation equipment included in the voltage transformation equipment group is connected to another circuit breaker in another one of the circuit breaker units in the busbar power distribution device; therefore, the above-mentioned first output end and the second output end can be connected to any circuit breaker in the circuit breaker units, but the circuit breakers to which they are connected are different; and any output end of the busbar power distribution device is also connected to any circuit breaker in the circuit breaker units, but the circuit breakers to which different output ends are connected are different.

[0064] In this embodiment, by ensuring that the circuit breakers connected to the output ends corresponding to different voltage transformation equipment are different, and the circuit breakers connected to different output ends of the busbar power distribution device are also different, the reliability of the offshore wind power transmission system is further enhanced.

[0065] In an exemplary embodiment, a set of voltage transformation equipment and a busbar power distribution device constitute an onshore offshore wind power collection station; the onshore offshore wind power collection station further includes auxiliary facilities, civil engineering, and buildings.

[0066] Among them, the busbar power distribution device, auxiliary facilities, civil engineering, buildings, and energy storage system can be shared in the onshore offshore wind power collection station, that is, the electric energy under at least two different power transmission methods can be collected through the power distribution device and then sent out through the line uniformly, saving the resources of using their respective onshore sending stations for power transmission under multiple power transmission methods.

[0067] As an example, as Figure 5 shown, the onshore offshore wind power collection station (onshore sending station) includes process production equipment, auxiliary facilities (shared), civil engineering, buildings (shared), and an energy storage system (shared); among them, the process production equipment includes equipment such as converters or step-up transformers or frequency converters, and a 500 kV busbar power distribution device; the auxiliary facilities (shared) include a station service power system, a lighting system, a heating, ventilation, and air conditioning system, and a hydraulic system; the civil engineering and buildings (shared) include site engineering, grounding, and building engineering.

[0068] In an embodiment, a method for sending out offshore wind power is provided, including: the input end of the busbar power distribution device is electrically connected to the set of voltage transformation equipment to collect the electric energy transmitted by the wind farm group to the set of voltage transformation equipment through the step-up substation group and send out the electric energy; among them, the wind farm group and the step-up substation group are located offshore; the set of voltage transformation equipment and the busbar power distribution device are located inland; the wind farm group includes at least a first type of wind farm and a second type of wind farm, the step-up substation group includes at least a first type of step-up substation electrically connected to the first type of wind farm and a second type of step-up substation electrically connected to the second type of wind farm, and the set of voltage transformation equipment includes at least a first type of voltage transformation equipment electrically connected to the first type of step-up substation and a second type of voltage transformation equipment electrically connected to the second type of step-up substation; the busbar power distribution device adopts a 3 / 2 breaker connection to send out the electric energy output by at least one of the first type of voltage transformation equipment and the second type of voltage transformation equipment received.

[0069] In this embodiment, the aggregated power distribution device adopts a 3 / 2 breaker connection. The inlets of the three power transmission modes are respectively connected to the string. By adopting the 3 / 2 breaker connection, multiple outgoing line elements and two groups of busbars can form a multi-loop connection, ensuring a high level of operation reliability. Moreover, the outage of any circuit breaker due to failure or maintenance will not cause the outage of the incoming and outgoing lines. Therefore, the outage of any power transmission mode will not affect the energy transmission of the other two power transmission modes, making the offshore wind power transmission method highly flexible. Even in the extreme case where both groups of busbars fail and trip simultaneously, causing all the circuit breakers on the busbar side to open, the two elements in the same string can still achieve the transmission of power flow through the intermediate tie breaker. Further, the flexible DC power transmission mode adopts a symmetric monopole connection, and the industrial frequency AC and low-frequency AC adopt a line-transformer bank connection, which can save the investment in submarine cables and offshore resources. Also, because of the simple connection, the number and weight of the offshore part of the power distribution device are reduced, saving equipment and platform resources.

[0070] Furthermore, when the industrial frequency AC transmits electric energy, there is no need to additionally configure an SVG (Static Var Generator). The energy storage system is connected to the 3 / 2 breaker connection string of the 500 kV aggregated power distribution device, with high reliability. Even if there is a fault in the offshore wind power transmission system, it will not affect the energy storage system's continued power transmission. Therefore, the offshore wind power transmission method of the above embodiment can meet the simultaneous access and aggregated transmission of flexible DC, industrial frequency AC, and low-frequency AC, improving the efficiency of electric energy transmission.

[0071] Furthermore, as an example, as Figure 6 shown, an offshore wind power transmission system 100 is provided, which includes a flexible DC offshore converter station connected to the flexible DC converter using a 320 kV submarine cable; an offshore industrial frequency step-up station connected to an AC switch or step-up equipment using a 500 kV, 50 Hz submarine cable; an offshore low-frequency step-up station connected to a frequency conversion device using a 330 kV, 20 Hz submarine cable; and finally, the power is uniformly output to the busbar and distribution device, which includes an energy storage system, a station service transformer, and a filter circuit, and transmits the electric energy in the form of 500 kV AC.

[0072] The technical features of the above embodiments can be combined arbitrarily. For the sake of brevity in description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as within the scope described in this specification.

[0073] The above-described embodiments merely represent several implementation manners of the present application. The description thereof is relatively specific and detailed, but it should not be construed as a limitation on the patent scope of the present application. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present application, several modifications and improvements can still be made, and these all fall within the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the appended claims.

Claims

1. An offshore wind power transmission system, characterized in that: The system at least comprises a wind farm group, a booster station group, a transformer equipment group and a convergence and distribution device which are electrically connected in sequence; wherein the wind farm group and the booster station group are located offshore; the transformer equipment group and the convergence and distribution device are located inland; The wind farm group includes at least a first type of wind farm and a second type of wind farm, the booster station group includes at least a first type of booster station electrically connected to the first type of wind farm, and a second type of booster station electrically connected to the second type of wind farm, and the transformer equipment group includes at least a first type of transformer equipment electrically connected to the first type of booster station, and a second type of transformer equipment electrically connected to the second type of booster station; The converging and distributing device adopts 3 / 2 circuit breaker connection, and is used to send out the electric energy output by at least one of the first type transformer equipment and the second type transformer equipment.

2. The system according to claim 1, characterized in that The first type of booster station includes any one of a flexible DC offshore converter station, an offshore power frequency booster station and an offshore low frequency booster station; and the second type of booster station includes the other of the flexible DC offshore converter station, the offshore power frequency booster station and the offshore low frequency booster station; The first type of transformer equipment includes any one of a flexible DC converter, an AC switch, a boost device and a frequency conversion device; the second type of transformer equipment includes the other one of the flexible DC converter, the AC switch, the boost device and the frequency conversion device.

3. The system according to claim 2, characterized in that Include at least two of the following: The flexible DC offshore converter station is electrically connected to the flexible DC converter via a DC submarine cable; The offshore power frequency boosting station is electrically connected to at least one of the AC switch and the boosting device via a first AC submarine cable; The offshore low-frequency booster station is electrically connected to the frequency conversion device via a second AC submarine cable.

4. The system according to claim 3, characterized in that A symmetrical monopole connection is adopted between the flexible DC offshore converter station and the flexible DC converter, and the DC submarine cable has a first length; The offshore power frequency boosting station and the AC switch or the boosting equipment are connected by a line transformer group; the first AC submarine cable is of the second length; The offshore low-frequency booster station and the frequency conversion device are connected by a line transformer group; the second AC submarine cable is of the third length; The first length is greater than the third length, and the third length is greater than the second length.

5. The system according to any one of claims 2 to 4, characterized in that: The frequency conversion device adopts IGBT power electronic devices to convert low-frequency voltage into industrial frequency voltage.

6. The system according to claim 1, characterized in that The first type of wind farm is electrically connected to the first type of booster station by a collector line, and the second type of wind farm is electrically connected to the second type of booster station by a collector line; The collector line confluence adopts single busbar segmented wiring; One of the first type of wind farm and the second type of wind farm comprises a low frequency wind farm.

7. The system according to claim 1, characterized in that The converging and distributing device comprises a first busbar, a second busbar, a plurality of circuit breaker units, a station transformer, an energy storage system and a filter circuit; Wherein, each of the circuit breaker units includes three connected circuit breakers, and at least four of the circuit breaker units are connected between the first busbar and the second busbar; Any one of the station transformer, the energy storage system and the filter circuit is connected to any one of the circuit breaker units.

8. The system according to claim 7, characterized in that The output end of the transformer equipment group includes a first output end of the first type of transformer equipment and a second output end of the second type of transformer equipment; wherein any output end of the transformer equipment group is connected to any one of the multiple circuit breaker units, and the output end of the busbar distribution device is connected to another one of the multiple circuit breaker units.

9. The system according to claim 1, characterized in that The transformer equipment group and the converging and distributing device constitute an onshore sea wind converging station; The onshore sea wind gathering station also includes auxiliary facilities, civil engineering and buildings.

10. A method for transmitting offshore wind power, characterized in that: The method comprises: The input end of the converging and distributing device is electrically connected to the transformer equipment group to collect the electric energy transmitted to the transformer equipment group by the wind farm group through the booster station group, and transmit the electric energy; Wherein, the wind farm group and the booster station group are located at sea; the transformer equipment group and the converging and distributing device are located inland; The wind farm group includes at least a first type of wind farm and a second type of wind farm, the booster station group includes at least a first type of booster station electrically connected to the first type of wind farm, and a second type of booster station electrically connected to the second type of wind farm, and the transformer equipment group includes at least a first type of transformer equipment electrically connected to the first type of booster station, and a second type of transformer equipment electrically connected to the second type of booster station; The converging and distributing device adopts 3 / 2 circuit breaker connection, and is used to send out the electric energy output by at least one of the first type transformer equipment and the second type transformer equipment.

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