Auxiliary Power System and Control for Rural and/or off grid Wind Turbines

Abstract

The present invention relates to a wind turbine park (100), comprising at least a first wind turbine (110) and a second wind turbine (120) for generating a power product, and a main line (101) connecting the first wind turbine (110) and the second wind turbine (120) for transporting the power product. The wind turbine park (100) further comprises an auxiliary power line (102) being connected to the first wind turbine (110) and the second wind turbine (120), wherein the auxiliary power line (102) is configured for transporting auxiliary power for a wind turbine maintenance or standby operation to at least one of the first wind turbine (110) and the second wind turbine (120). Furthermore, the wind turbine park (100) comprises an auxiliary power unit (103) for generating the auxiliary power, wherein the auxiliary power unit (103) is connected to the auxiliary power line (102).

Claims

1. A wind turbine park (100), comprising at least a first wind turbine (110) and a second wind turbine (120) for generating a power product, a main line (101) connecting the first wind turbine (110) and the second wind turbine (120) for transporting the power product, an auxiliary power line (102) being connected to the first wind turbine (110) and the second wind turbine (120), wherein the auxiliary power line (102) is configured for transporting auxiliary power for a wind turbine maintenance or standby operation to at least one of the first wind turbine (110) and the second wind turbine (120), an auxiliary power unit (103) for generating the auxiliary power to the first wind turbine (110) and the second wind turbine (120), wherein the auxiliary power unit (103) is connected to the auxiliary power line (102).

2. The wind turbine park (100) according to claim 1, wherein the auxiliary power line (102) is configured for transmitting less than less than 1 MW, more particularly less than 500 kW, in particular less than 150 kW.

3. The wind turbine park (100) according to claim 1, wherein the power product is electrical power, wherein the main line (101) is an electrical power line for transporting the generated electrical power.

4. The wind turbine park (100) according to claim 1, wherein the power product is a power fluid, in particular a liquid or a gas, wherein the main line (101) is a fluid pipe for transporting the generated power fluid.

5. The wind turbine park (100) according to claim 4, wherein at least one of the first wind turbine (110) and the second wind turbine (120) comprises an electrolyzer unit (104) for generating hydrogen and/or oxygen as power fluid.

6. The wind turbine park (100) according to claim 1, wherein the auxiliary power unit (103) is mounted to the first wind turbine (110), wherein in particular the second wind turbine (120) is free of a further auxiliary power unit (103).

7. The wind turbine park (100) according to claim 1, wherein the auxiliary power unit (103) is mounted to an auxiliary power platform being spaced apart from the first wind turbine (110) and the second wind turbine (120).

8. The wind turbine park (100) according to claim 1, wherein the auxiliary power unit (103) is a battery, wherein the battery is in particular chargeable by electrical power generated by at least one of the first wind turbine (110) and the second wind turbine (120) and/or, wherein the auxiliary power unit (103) is a fuel cell being operated by the power product.

9. The wind turbine park (100) according to claim 1, further comprising an auxiliary power controller (105) configured for controlling the auxiliary power provided to the first wind turbine (110) and to the second wind turbine (120), wherein the auxiliary power controller (105) is configured for determining a maintenance or standby operation of the first wind turbine (110) and the second wind turbine (120).

10. The wind turbine park (100) according to claim 9, wherein the auxiliary power line (102) comprises a predetermined power threshold value for the transported auxiliary power through the auxiliary power line (102), wherein the power threshold value is in particular less than 500 kW, in particular less than 150 kW, wherein the auxiliary power controller (105) is configured for providing auxiliary power to the first wind turbine (110) and to the second wind turbine (120) under consideration of the predetermined power threshold value.

11. The wind turbine park (100) according to claim 10, wherein the auxiliary power controller (105) is configured to provide auxiliary power subsequently first to the first wind turbine (110) and subsequent to the second wind turbine (120) if the total required auxiliary power of the first wind turbine (110) and the second wind turbine (120) in sum exceeds the power threshold value of the auxiliary power line (102).

12. The wind turbine park (100) according to claim 10, wherein the auxiliary power controller (105) is configured for controlling the maintenance or standby operation of at least one of the first wind turbine (110) and the second wind turbine (120).

13. The wind turbine park (100) according to claim 12, wherein the maintenance or standby operation comprises a plurality of maintenance or standby tasks, in particular pitch control (106) of a blade of a wind turbine or yaw control (107) of a wind turbine nacelle, wherein the auxiliary power controller (105) is configured for controlling the timing of the maintenance or standby tasks in order to comply with the power threshold value of the auxiliary power line (102).

14. The wind turbine park (100) according to claim 1, wherein the wind turbine park (100) is decoupled from a power grid.

15. A method of operating a wind turbine park (100) according to claim 1, the method comprising generating a power product by at least one of the first wind turbine (110) and the second wind turbine (120), transporting the power product by the main line (101), generating auxiliary power by the auxiliary power unit (103), transporting by the auxiliary power line (102) auxiliary power for a maintenance or standby operation to at least one of the first wind turbine (110) and the second wind turbine (120).

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0041] FIG. 1 shows a schematic view of a wind turbine park according to an exemplary embodiment of the present invention.

[0042] FIG. 2 shows a schematic view of an auxiliary power controller and an exemplary control procedure according to an exemplary embodiment of the present invention.

[0043] FIG. 3 shows a schematic view of a cross-section of a main line and an auxiliary power line according to an exemplary embodiment of the present invention.

[0044] FIG. 4 shows a schematic view of a wind turbine park comprising a plurality of wind turbines connected in series and in parallel according to an exemplary embodiment of the present invention.

DETAILED DESCRIPTION

[0045] The illustrations in the drawings are schematically. It is noted that in different figures, similar or identical elements are provided with the same reference signs.

[0046] FIG. 1 shows a schematic view of a wind turbine 100 park according to an exemplary embodiment of the present invention. The wind turbine park 100, comprising at least a first wind turbine 110 and a second wind turbine 120 for generating a power product, and a main line 101 connecting the first wind turbine 110 and the second wind turbine 120 for transporting the power product. The wind turbine park 100 further comprises an auxiliary power line 102 being connected to the first wind turbine 110 and the second wind turbine 120, wherein the auxiliary power line 102 is configured for transporting auxiliary power for a wind turbine maintenance or standby operation to at least one of the first wind turbine 110 and the second wind turbine 120. Furthermore, the wind turbine park 100 comprises an auxiliary power unit 103 for generating the auxiliary power, wherein the auxiliary power unit 103 is connected to the auxiliary power line 102.

[0047] The wind turbines 110, 120, 130 shown in the wind turbine park 100 comprise a wind turbine tower and a respective nacelle, to which rotatable wind turbine blades are coupled. Upon rotation of the blades by wind force in an operating mode of the wind turbine 110, 120, 130, a generator in the nacelle generates direct current and electrical power, respectively. The generated electrical power is used to produce the power product which can be transported by the mainline 101 to a central storage for the power product, such as huge fluid tanks, or a power product grid 401 (see FIG. 4), e.g. a respective pipeline system exporting the power product out of the wind turbine park 100 to its final destination.

[0048] The power product generated by the respective wind turbines 110, 120, 130 is in the exemplary embodiment shown in FIG. 1 a power fluid and the main line 101 is a fluid pipe for transporting the generated power fluid. The power product is e.g. hydrogen or oxygen generated by an electrolyzer unit 104 that is operated by the electrical power of the respective wind turbine 110, 120, 130.

[0049] The auxiliary power line 102 connects the wind turbines 110, 120, 130 and is designed for providing auxiliary power for a wind turbine maintenance or standby. The auxiliary power is needed for standby operation and maintenance operations, such as yawing 107 the nacelle and pitching 106 blades, operating heat units for example for deicing systems of the blade, for energizing electrical components, such as transformers and the like.

[0050] As can be seen in the exemplary embodiment in FIG. 1, all wind turbines 110, 120, 130 of the wind turbine park are coupled to one common auxiliary power line 102.

[0051] In the exemplary embodiment in FIG. 1, one auxiliary power unit 103 is coupled to the auxiliary power line 102 for generating auxiliary power and for transmitting the auxiliary power to the respective wind turbines 110, 120, 130. The auxiliary power unit 103 is mounted in the exemplary embodiment to wind turbine 120.

[0052] The wind turbine park 100 is for example an offshore wind turbine park having the power line 101 and the auxiliary power line 102 below the sea level 108.

[0053] The auxiliary power unit 103 is for example a fuel cell driven by hydrogen and/or oxygen generated by the wind turbine 120. The hydrogen and/or oxygen may be the power product generated by the wind turbines 110, 120, 130. For example, the wind turbines 110, 120, 130 comprise respective electrolyzer units 104 for generating hydrogen and/or oxygen as power fluid. From the electrolyzer units 104, the generated hydrogen and/or oxygen is transported by the main line 101 out of the wind turbine park.

[0054] The auxiliary power unit 103 may be a fuel cell and is coupled for example to the electrolyzer unit 104 of the wind turbine 120 and/or the adjacent electrolyzer units 104 of the wind turbines 110, 130 in order to receive respective fuel, such as hydrogen or oxygen generated by the electrolyzer 104. Therefore, the auxiliary power unit 103 is coupled by a further source system to the electrolyzer units 104 or is coupled to the main line 101 for receiving the hydrogen and/or oxygen. Specifically, the auxiliary power unit 103 receives hydrogen or oxygen from an electrolyzer unit 104 that is operated by a wind turbine, which is in an operating state. Alternatively, the auxiliary power unit 103 may receive fuel (hydrogen or other combustible fuel, such as Diesel) from a fuel tank. For example, the auxiliary power unit 103 may comprise a fuel cell driven by green fuel produced by renewable energy. Hence, if the auxiliary power unit 103 receives green fuel from a fuel tank, all wind turbines 110, 120, 130 may be in a standby mode. The auxiliary power unit 103 may also comprise a battery, wherein the battery is in particular chargeable by electrical power generated by at least one of the first wind turbines 110, 120, 130.

[0055] The electrolyzer units 104 are fed by a base material, such as water, and produces by the use of the electrical power generated by the wind turbine generators of the wind turbines 110, 120, 130 the respective power product, e.g. gas, such as hydrogen and oxygen. The base material may be provided by supplying pipelines or, e.g. in case of water as base material, from the sea/lake/river or the groundwater. Specifically, the electrolyzer unit 104 generates a first electrolyzed gas, such as hydrogen, which is transported by the main line 101. Additionally, the electrolyzer unit may generate a second electrolyzed gas, such as oxygen. The second electrolyzed gas may be bled off or may be transported in a further main line. The wind turbine 110, 120, 130 may comprise an optional storage tank for storing the power product before being transported by the main line 101.

[0056] Hence, the auxiliary power unit 103 provides auxiliary power for the wind turbine 120 at which the auxiliary power unit 103 is installed but also for the other wind turbines 110, 130 of the wind turbine park 100. Hence, since the auxiliary power unit 103 is part of the wind turbine park 100 and is coupled to the auxiliary power line 102, the wind turbine park 100 may be decoupled from a supplying power grid and an off-grid wind turbine park 100 configured for converting electricity to hydrogen directly at the location of the wind turbine 110, 120, 130 can be provided.

[0057] The wind turbine park 100 comprises an auxiliary power controller 105 configured for controlling the auxiliary power provided to the wind turbines 110, 120, 130. The auxiliary power controller 105 is configured for determining a maintenance or standby operation of the wind turbines 110, 120, 130. The auxiliary power controller 105 is configured for determining the auxiliary power requirements of each single wind turbine 110, 120, 130 and is configured for determining the power output of the auxiliary power unit 103.

[0058] FIG. 2 shows a schematic view of an auxiliary power controller 105 and an exemplary control procedure according to an exemplary embodiment of the present invention.

[0059] The auxiliary power controller 105 controls on the basis of the of the available generated auxiliary power the supply of auxiliary power to the respective wind turbines 110, 120, 130. For example, if sufficient auxiliary power is available, all wind turbines 110, 120, 130 are supplied with auxiliary power in order to conduct maintenance and standby operations. If the sum of the required auxiliary power of the wind turbines 110, 120, 130 exceeds the generated auxiliary power, then the auxiliary power unit 103 is controlled by the auxiliary power controller 105 for transmitting subsequently the auxiliary power to the respective subsequently. For example, in a first time period, the first wind turbine 110 receives respective auxiliary power by the auxiliary power unit 103 and if the maintenance and standby operating procedures of the first wind turbine 110 have been finished, subsequently in a second time period, the second wind turbine 120 receives respective auxiliary power by the auxiliary power unit 103.

[0060] By the auxiliary power controller 105 the maximum power capacity of the auxiliary power line 102 can be considered and hence the auxiliary power line 102 must not be designed for the absolute maximum power case where all wind turbines 110, 120, 130 receives the maximal needed auxiliary power. Hence, the auxiliary power line 101 comprises a predetermined power threshold value for the transported auxiliary power through the auxiliary power line which can be considered by the auxiliary power controller 105. The power threshold value for the maximum power transmitted by the auxiliary power line 102 is in particular less than 300 kW.

[0061] For example, the wind turbines 110, 120, 130 may require 150 kW as maximum for maintenance mode (e.g. for yawing the nacelle or for pitching the blades) and around 50 kW in standby mode (e.g. for heaters, communication units or other standby equipment). The auxiliary power line 102 may be limited in its power capacity by the line diameter, material, etc. Hence, the maximum power capacity defines the threshold value. The auxiliary power controller 105 is scheduling the maintenance modes for the wind turbines 110, 120, 130 and allows for example only maintenance modes for the wind turbines 110, 120, 130 until the threshold value for the auxiliary line capacity is not exceeded.

[0062] Hence, in the example of four wind turbines 110, 120, 130, a load example may be: 50 kW+50 kW+50 kW+150 kw=300 kw, since three wind turbines 120, 130 are in the standby mode (50 kW power consumption) and only one wind turbine 110 is in the maintenance mode (150 kW power consumption). The wind turbine 110 is running in a maintenance mode, such as yawing the nacelle, pitching the blade, operating heat units, energizing of the transformer and other electrical components. Hence, in the example, a threshold value of 300 kW is not exceeded.

[0063] The wind turbines 110, 120, 130 request the auxiliary power controller 105 for power, if needed. The auxiliary power controller 105 schedules the activities (standby/maintenance operations) in the wind turbines 110, 120, 130 in order to prevent exceeding above the threshold value of the maximum power capacity of the auxiliary power line 102.

[0064] Furthermore, the wind turbine 110 that needs auxiliary power or is in a hazardous state is prioritized by the auxiliary power controller 105. The other wind turbines 120, 130 e.g. located on the same array are set on standby with a minimum power consumption in order to not exceed the threshold value. The wind turbine 110 can use all the auxiliary power needed to make the task. After the task has been finished the other wind turbines 120, 130 are enabled to use normal consumption again or may be driven in a maintenance mode.

[0065] Summarizing, if the design of the auxiliary power line 102 does only allow a maximum threshold value for the transmitted power, the auxiliary power controller 105 controls the auxiliary power in such a manner, that the maximum threshold value of the auxiliary power transmitted through the auxiliary power line 101 is met.

[0066] FIG. 3 shows a schematic view of a cross-section of a main line 101 and an auxiliary power line 102 according to an exemplary embodiment of the present invention. The auxiliary cable/line 102 is attached to the main line 101, e.g. a gas pipeline. Also, communication cables (fibers) can be integrated in the auxiliary cable 102 or independently attached to the main line 101. The auxiliary power line 102 is configured for transmitting less than 500 kw, in particular less than 105 kW. In a further exemplary embodiment, the auxiliary power line 102 is designed for transmitting voltage less than 50 kV, specifically less than 10 kV, more specifically less than 1 kV. Accordingly, the auxiliary power line 102 is designed with a smaller capacity and accordingly a smaller diameter. As can be seen from FIG. 3, the diameter of the auxiliary power line 102 is much smaller than the diameter if the main line 101.

[0067] FIG. 4 shows a schematic view of a wind turbine park 100 comprising a plurality of wind turbines 110, 120, 130 connected in series and in parallel according to an exemplary embodiment of the present invention. In the example, four wind turbines 110, 120, 130 are connected with the main line 101 and the auxiliary line 102 in series along a respective string 402. Specifically more than seven, for example 8, wind turbines 110, 120, 130 are connected with the main line 101 and the auxiliary line 102 in series along a respective string 402. The strings 402 are connected in parallel to a central string 403. The part of the main line 101 in the main string 403 is coupled to an external power product grid 401, such as a power grid or a pipeline system, outside of the wind turbine park 100.

[0068] Hence, specifically the auxiliary line 102 can be connected by loop configurations to enable big clusters of wind turbines 110, 120, 130 which can be operated together by auxiliary power generated by a common auxiliary power unit 103.

[0069] It should be noted that the term comprising does not exclude other elements or steps and a or an does not exclude a plurality. Also elements described in association with different embodiments may be combined. It should also be noted that reference signs in the claims should not be construed as limiting the scope of the claims.