Tether coupling method

Abstract

To prevent deterioration in the response of a winch.SOLUTION: A tether coupling method includes a step of coupling another tether different from one tether to the other end of the one tether whose one end is connected to a kite, in a separable manner during flight of the kite.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to the technical field of methods for connecting tethers to moor kites. [Background technology]

[0002] As a method of this type, for example, it has been proposed to connect one fixed rope having one end connected to a submersible power generation platform to another fixed rope having one end connected to a waterway (see Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2018-508712 Summary of the Invention [Problem to be solved by the invention]

[0004] Part of the tether that anchors a kite is often wound around a drum installed on the ground, for example. The higher the kite's target flight altitude, the longer the tether that anchors the kite. This means that the size of the drum onto which the tether is wound also increases. If the drum becomes larger, the winch also becomes larger, which poses a technical problem: the response of the winch deteriorates.

[0005] The present invention has been made in view of the above-mentioned problems, for example, and has an object to provide a tether connecting method that can suppress deterioration of winch response. [Means for solving the problem]

[0006] A method of connecting tethers according to one aspect of the present invention includes a step of connecting another tether, different from one end of a tether whose other end is connected to the kite, in a detachable manner while the kite is flying. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a diagram illustrating an example of a wind power generation system. [Figure 2] FIG. 10 is a diagram showing an example of a method for connecting tethers. [Figure 3] 10 is a flowchart showing an example of a method for connecting tethers. [Figure 4] 10 is a flowchart illustrating an example of a method for detaching a tether. [Figure 5] FIG. 10 is a diagram showing an example of a connection mode of a tether. DETAILED DESCRIPTION OF THE INVENTION

[0008] An embodiment of a tether connecting method will be described with reference to FIGS.

[0009] First, an overview of a tethered wind power generation system using kites will be described with reference to FIG. 1. In FIG. 1, the wind power generation system includes kites 1 and ground equipment 2. The ground equipment 2 may include a winch having a drum around which a tether is wound to moor the kites 1. The ground equipment 2 may further include a generator connected to the rotating shaft of the drum. Since the ground equipment 2 moors the kites 1, it may also be called a mooring device. The shape of the kites 1 shown in FIG. 1 is an example and is not limited to this. Although FIG. 1 shows a single tether mooring the kites 1, the kites 1 may be moored by multiple tethers.

[0010] In a wind power generation system, when the kite 1 ascends, the tether is unwound from the drum of the winch as the kite 1 ascends. This unwounding of the tether causes the drum to rotate. The rotation of the drum then causes the generator to rotate, generating electricity. When the tether has been unwound to a predetermined length, or after a predetermined time has elapsed, the motor of the winch rotates the drum in a direction to reel in the tether. As a result, the reeling of the tether causes the kite 1 to descend. In a wind power generation system, power is generated by repeatedly unwounding and reeling the tether.

[0011] Next, a method for connecting the tethers that moor the kite 1 will be described with reference to Figures 2 and 3. Here, a method for extending the tethers that moor the kite 1 by connecting a tether 32 to a tether 31 that moor the kite 1 will be described.

[0012] In FIG. 2(a), the tether 31 extending from the drum 21 towards the kite 1 may pass through the lead part 51. One end of the tether 31 is connected to the kite 1. Note that one end of the tether 31 may be directly connected to the kite 1 or indirectly connected to the kite 1. Here, "indirectly connected" may mean that the kite 1 and one end of the tether 31 are connected via another member (for example, another tether, etc.). Note that the lead part 51 and the lead part 52 described later may be called a fairlead.

[0013] A portion of tether 31 is wound around drum 21. At this time, tether 31 may be wound around drum 21 so that the other end 31a of tether 31 protrudes from drum 21. In the state shown in FIG. 2(a), the rotation shaft of drum 21 may be connected to a generator. End 31a of tether 31 is disposed in coupling device 40. Note that if the length of tether 31 wound around drum 21 becomes shorter than a predetermined length, end 31a may be disposed in coupling device 40. In other words, if the length of tether 31 wound around drum 21 is longer than a predetermined length, end 31a does not need to be disposed in coupling device 40.

[0014] The tether 32 has an end 32a and an end 32b. The end 32a of the tether 32 is disposed in the coupling device 40. The portion of the tether 32 extending from the drum 22 toward the end 32a may pass through the lead portion 52 and a plurality of guide pulleys. In other words, the end 32a pulled out from the drum 22 around which the tether 32 is wound may be disposed in the coupling device 40 through the lead portion 52 and a plurality of guide pulleys. As shown in FIG. 2(a), the tether 32 may be wound around the drum 22 so that the end 32b of the tether 32 (i.e., the end opposite the end 32a connected to the end 31a of the tether 31) protrudes from the drum 22. The drums 21 and 22 may constitute a part of the ground facility 2 shown in FIG. 1. In the state shown in FIG. 2(a), the rotating shaft of the drum 22 does not need to be connected to a generator.

[0015] For example, the connecting device 40 may automatically connect the tether 31 and the tether 32 when the end 31a of the tether 31 and the end 32a of the tether 32 are placed in the connecting device 40. For example, a connecting mechanism may be attached to each of the end 31a of the tether 31 and the end 32a of the tether 32. In this case, the connecting device 40 may connect the tether 31 and the tether 32 by engaging the connecting mechanism attached to the end 31a with the connecting mechanism attached to the end 32a. Examples of connecting mechanisms include mechanical couplings and buckles. In this case, the connected tethers 31 and 32 can be separated by releasing the engaged state of the connecting mechanisms. For example, the end 31a of the tether 31 and the end 32a of the tether 32 may not be attached to each of the end 31a of the tether 31 and the end 32a of the tether 32. In this case, the connecting device 40 may connect the tethers 31 and 32 by twisting the vicinity of the end 31a of the tether 31 with the vicinity of the end 32a of the tether 32. In this case, the connected tethers 31 and 32 can be separated by untwisting the twisted tethers 31 and 32. In this way, the connecting mechanism 40 may connect the tethers 31 and 32 in a separable manner.

[0016] After the tether 31 and the tether 32 are connected, the tethers 31 and 32 may be removed from the connecting device 40 and the guide pulley, for example. Then, the portion of the tether 31 wound around the drum 21 may be unwound from the drum 21, thereby removing the tether 31 from the lead portion 51 and the drum 21. As a result, as shown in FIG. 2(b), the tether 32 extends from the drum 22 toward the kite 1. In the state shown in FIG. 2(b), the rotating shaft of the drum 22 may be connected to a generator. In FIG. 2(b), the reference numeral "33" indicates the connecting portion between the tether 31 and the tether 32. By connecting the tether 32 to the tether 31, the overall length of the tether mooring the kite 1 is increased. Therefore, the tether 32 may be referred to as an extension tether. A connecting mechanism may be attached to each of the ends 32a and 32b of the tether 32. In this case, the extension tether can be said to have a connecting mechanism at both ends.

[0017] The tether coupling method will be explained with reference to the flowchart in Fig. 3. In Fig. 3, an end of one tether (e.g., end 31a of tether 31) is placed in coupling device 40 (step S101). In parallel with or before or after the processing of step S101, an end of another tether (e.g., end 32a of tether 32) is placed in coupling device 40 (step S102). Thereafter, coupling device 40 couples the one tether to the other tether (step S103).

[0018] In the process of step S101, for example, the connecting device 40 may draw the end of one tether into the connecting device 40, thereby placing the end of the one tether in the connecting device 40. Similarly, in the process of step S102, for example, the connecting device 40 may draw the end of the other tether into the connecting device 40, thereby placing the end of the other tether in the connecting device 40. In addition, the connecting device 40 may connect two or more tethers to one tether.

[0019] The tether 31 and the tether 32 may be the same type of tether. The tether 31 and the tether 32 may be different types of tether. For example, by connecting the tether 31 and the tether 32, the kite 1 can fly at a higher altitude. In other words, the tether 31 will be used at a higher altitude than the tether 32. As the altitude increases, the temperature drops, making the tether (for example, the water contained in the tether) more likely to freeze. In view of this, the tether 31 may be a tether that is more resistant to freezing than the tether 32. In other words, the tether 31 may be a tether that is resistant to freezing.

[0020] As described above, in a tether-type wind power generation system, the tether is repeatedly unwound and wound to generate power. As shown in FIG. 2(b), when tether 32 is connected to tether 31, tether 32 is wound around drum 22. In this case, to generate power, tether 32 is unwound from drum 22 and wound around drum 22. As a result, at least a portion of tether 32 may be damaged by friction. In view of this, tether 32 may be a tether that is more abrasion-resistant than tether 31. In other words, tether 32 may be an abrasion-resistant tether.

[0021] Next, a method for separating the tethers will be described with reference to Figures 2 and 4. Here, a method for shortening the tethers mooring the kites 1 by separating the tethers 31 and 32 mooring the kites 1 will be described.

[0022] For example, in the state shown in FIG. 2(b), the tether 32 may be wound onto the drum 22 until the distance from the drum 22 (in other words, the ground equipment 2) to the connecting part 33 reaches a predetermined distance. Then, the tether 31 may be wound onto the drum 21. This prevents the tension applied to the tether 31 due to the kite 1 from being applied to the connecting part 33. Then, the connecting part 33 may be placed on the connecting device 40. Note that if excessive force is not applied to the connecting part 33 and the connecting device 40, the tether 31 may be wound onto the drum 21 after the connecting part 33 is placed on the connecting device 40.

[0023] The coupling device 40 may separate the end 31 a of the tether 31 and the end 32 a of the tether 32, which constitute the coupling portion 33. For example, after the tether 31 and the tether 32 are separated, the rotating shaft of the drum 21 may be connected to a generator. Furthermore, the drum 22 around which the tether 32 is wound may be removed from the ground facility 2.

[0024] The tether separation method will be explained with reference to the flowchart in Fig. 4. In Fig. 4, the tether mooring the kite 1 is wound, for example, onto the drum 22 (step S201). Then, the connecting portion of the tether (for example, the connecting portion 33) is placed on the connecting device 40 (step S202). Before the processing of step 202, the tether (for example, the tether 31) on the kite 1 side of the connecting portion of the tether may be wound onto a drum (for example, the drum 21) different from the drum 22. After the processing of step S202, the connecting device 40 separates one tether from the other tether (step S203).

[0025] (Technical Effects) The higher the target flight altitude of the kite 1, the longer the length of the tether mooring the kite 1. If the length of one tether is increased to achieve the target flight altitude of the kite 1, the size of the drum around which the tether is wound also increases. In contrast, in this embodiment, the tether 32 is connected to the tether 31 that moors the kite 1, thereby increasing the overall length of the tethers mooring the kite 1. With this configuration, the length of each tether can be significantly shorter than the length required to achieve the target flight altitude of the kite 1. This makes it possible to reduce the size of the drum (e.g., at least one of the drums 21 and 22) around which the tether (e.g., at least one of the tethers 31 and 32) is wound. Therefore, according to this embodiment, deterioration of the winch response can be suppressed.

[0026] In this embodiment, there is no limit to the number of tethers that can be connected. Therefore, the length of each tether may be shortened in order to reduce the size of the drum on which the tether is wound. In other words, in this embodiment, the length of each tether may be actively shortened to reduce the size of the drum. In this case, the reduction in the size of the drum can improve the response of the winch. In addition, the reduction in the size of the drum can improve the transportability of the drum (i.e., at least one of a drum on which a tether is wound and a drum on which a tether is not wound).

[0027] Furthermore, some of the connected tethers that serve as the tether for mooring the kite 1 may be separated. Furthermore, instead of the separated tether, a new tether may be connected to the tether for mooring the kite 1. In other words, some of the tethers that serve as the tether for mooring the kite 1 may be replaced. With this configuration, maintenance of the tether for mooring the kite 1 can be performed while the kite 1 is flying.

[0028] (First Modification) A first variant of the tether connecting method will be described with reference to Fig. 4. As mentioned above, two or more tethers may be connected to one tether that moors the kite 1. In the example shown in Fig. 5, tethers 32 and 34 are connected to tether 31. In this case, the connecting portion 33 may mean the connecting portion between tether 31, tether 32, and tether 34. Here, tether 34 may be a tether with higher conductivity than tether 32. And tether 34 may be grounded.

[0029] Depending on weather conditions, lightning may strike the kite 1 while it is in flight. In this case, if no measures are taken, there is a possibility that a current caused by lightning will flow to the ground equipment 2 (see FIG. 1) via the tether mooring the kite 1. In contrast, in the example shown in FIG. 5, even if lightning strikes the kite 1 while it is in flight, it is expected that most of the current caused by lightning will flow to the tether 34. Therefore, according to the first modification, it is possible to prevent damage to the ground equipment 2 caused by a current caused by lightning. In this case, the tether 34 may be called a lightning protection tether.

[0030] (Second Modification) A second modification of the tether connection method will be described. The kite 1 according to the second modification may be a kite used in a tethered wind power generation system, or may be a kite not used in a tethered wind power generation system. Here, an example of a kite not used in a tethered wind power generation system is a kite for solar power generation equipped with a solar panel.

[0031] In a second modification, a sensor may be disposed at the connection between one tether and another tether (for example, connection 33 between tether 31 and tether 32 shown in FIG. 2(b)). Examples of the sensor include at least one of a temperature sensor, a humidity sensor, an altitude sensor, a barometric pressure sensor, a wind speed sensor, a wind direction sensor, and a GPS (Global Positioning System) sensor. The sensor disposed at the connection may be a radiosonde.

[0032] According to the second variant, for example, weather observation can be performed by a sensor located at the connection between one tether and another tether. In addition, since the kite 1 can stay in the air for a relatively long period of time, fixed-point weather observation can be performed by the sensor.

[0033] Aspects of the invention derived from the above-described embodiment and modifications will be described below.

[0034] A method of connecting tethers according to one aspect of the invention includes a step of connecting another tether, different from one end of a tether whose other end is connected to the kite, in a detachable manner while the kite is flying.

[0035] The first tether may be a freeze-resistant tether, and the second tether may be an abrasion-resistant tether. The second tether may be a lightning protection tether. Before the first tether is connected to the second tether, a portion of the first tether may be wound around the drum so that the second end protrudes from the drum. A sensor may be disposed at a connection between the second end of the first tether and the second tether.

[0036] The present invention is not limited to the above-described embodiments, but can be modified as appropriate within the scope of the claims and the gist or concept of the invention as can be read from the entire specification, and tether connection methods involving such modifications are also included in the technical scope of the present invention. [Explanation of symbols]

[0037] 1...Kite, 31, 32...Tether

Claims

1. During the flight of the kite, one end of the tether is connected to the kite, and the other end of the tether is connected to the kite in a detachable manner. A method for connecting a tether.

2. the first tether is a freeze-resistant tether, The other tether is an abrasion-resistant tether.

2. The tether connecting method according to claim 1.

3. The other tether is a lightning protection tether.

2. The tether connecting method according to claim 1.

4. Before the first tether is connected to the second tether, a portion of the first tether is wound around the drum so that the other end of the first tether protrudes from the drum.

2. The tether connecting method according to claim 1.

5. A sensor is disposed at a connection between the other end of the one tether and the other tether.

2. The tether connecting method according to claim 1.

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