A WIND ENERGY PARK COMPRISING A WIND TURBINE AND AN AIRBORNE WIND ENERGY SYSTEM

Abstract

A wind park with wind turbines and airborne wind energy systems where a first zone and a second zone is defined for at least one of the airborne wind energy systems such that the risk of collision between a part of that airborne wind energy systems and a part of one of the wind turbines is higher when the airborne unit of that airborne wind energy system is in the second zone than when it is in the first zone, and different control parameters are applied to the control of at least one of the wind turbine and the airborne wind energy system depending on the position of the airborne unit relative to the defined zones.

Claims

1. A method of operating a wind park, comprising at least one wind turbine and at least one airborne wind energy system, the wind turbine comprising a tower, at least one nacelle mounted on the tower and a rotor coupled to the nacelle and rotatable about a rotation axis for generating electrical energy for a power grid, the airborne wind energy system comprising an airborne unit, a base, and a cable connecting the airborne unit to the base, the method comprising the steps of: defining for at least one of the airborne wind energy systems, a first zone and a second zone such that the risk of collision between a part of that airborne wind energy systems and a part of one of the wind turbines is higher when the airborne unit of that airborne wind energy system is in the second zone than when it is in the first zone; determining a position of the airborne unit, and applying a first set of control parameters to the control of at least one of the wind turbine and the airborne wind energy system if the position of the airborne unit is in the first zone, and applying a second set of control parameters to the control of at least one of the wind turbine and the airborne wind energy system if the position of the airborne unit is in the second zone.

2. The method according to claim 1, further comprising defining a third zone in which collision between the wind turbine and the airborne wind energy system is more likely to occur than in the second zone and applying a third set of control parameters to the control of at least one of the wind turbine and the airborne wind energy system if the airborne unit is within the second zone.

3. The method according to claim 1, comprising the step of redefining at least one of the first zone, the second zone, and the third zone based on an operating condition of at least one wind turbine or airborne wind energy system of the wind park.

4. The method according to claim 1, comprising the step of redefining at least one of the first zone, the second zone, and the third zone based on a control parameter of at least one wind turbine or airborne wind energy system of the wind park.

5. The method according to claim 3, wherein the step of redefining the zone is carried out while electrical energy is generated.

6. The method according to claim 3, wherein the step of redefining the zone is carried out continuously.

7. The method according to claim 1, comprising the step of defining at least one of the first zone, the second zone and the third zone as a static zone which is not re-definable.

8. The method according to claim 1, wherein the wind park comprises a computer system configured to define the control parameters and control the wind turbine and/or the airborne wind energy system, wherein the first zone and the second zone are defined in the computer system, and wherein the computer system is configured, based on the location of the airborne unit, to select and execute the first or the second set of control parameters.

9. The method according to claim 1, wherein at least one of the first set of control parameters, the second set of control parameters, and the third set of control parameters comprises at least one of an orientation of the rotation axis, a length of the cable, a cable roll in and out speed, a speed of the rotor, a position of the blades and a position of the airborne unit.

10. The method according to claim 1, wherein the set of operational parameters are applied to more than one wind turbine or airborne wind energy system of the wind park.

11. A wind park, comprising at least one wind turbine and at least one airborne wind energy system, the wind turbine comprising a tower, the wind turbine further comprising at least one nacelle mounted on the tower and a rotor coupled to the nacelle and rotatable about a rotation axis for generating electrical energy for a power grid, the airborne wind energy system comprising an airborne unit, a base, and a cable connecting the airborne unit to the base, the wind park further comprising an electronic data storage and an electronic controller operable on data in the data storage, wherein the electronic data storage comprises a data set for at least one of the airborne wind energy system, the data set comprising at least a first zone data set defining a first zone, and a second zone data set defining a second zone in which collision between the wind turbine and the airborne wind energy system is higher than in the first zone, the wind park further comprising a position determining structure configured for determining a position of the airborne unit of that airborne wind energy system, and the electronic controller being configured to process the position data and the first zone data and the second zone data, and based thereon to determine if the airborne unit is in the first zone or in the second zone, and to apply a first set of control parameters to control at least one of the wind turbine and the airborne wind energy system if the position of the airborne unit is in the first zone, and to apply a second set of control parameters to the control of at least one of the wind turbine and the airborne wind energy system if the position of the airborne unit is in the second zone.

12. The wind park according to claim 11, wherein the electronic data storage comprises at least a third zone data set defining a third zone in which collision between the wind turbine and the airborne wind energy system is more likely to occur than in the second zone and wherein the electronic controller is configured to apply a third set of control parameters to at least one of the wind turbine and the airborne wind energy system if the airborne unit is within the second zone.

13. The wind park according to claim 11, wherein electronic controller is configured to redefine at least one of the first, second, and third zone based on a wind speed, a wind direction, a length of the cable, and positions of the blades

14. The wind park according to claim 13, wherein the controller is configured to redefine at least one of the first, second, and third zone while electrical energy is generated.

15. The wind park according to claim 13, wherein the controller is configured to redefine at least one of the first, second, and third zone while the set of control parameters of at least one of the wind turbine and the airborne wind energy system are applied for controlling operation.

16. The wind park according to claim 13, wherein the controller is configured to redefine at least one of the first, second, and third zone continuously.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0055] The invention will now be described in further detail with reference to the accompanying drawings in which

[0056] FIGS. 1-5 illustrate wind parks according to three different embodiments and with one wind turbine and airborne wind energy system;

[0057] FIGS. 6-11 illustrate wind parks according to three different embodiments and with different zones defined for the control.

DETAILED DESCRIPTION OF THE DRAWINGS

[0058] FIG. 1a illustrates a wind park with a single wind turbine 1 and a single airborne wind energy system 2.

[0059] The wind turbine 1 comprises a tower 3 and a nacelle 4 mounted on the tower 3. A rotor 5 is coupled to the nacelle 4 in a manner which allows the rotor 5 to rotate relative to the nacelle 4 when wind is acting on wind turbine blades 10 mounted on the rotor 5.

[0060] The airborne wind energy system 2 comprises an airborne unit 6 and a base 7. The base and the airborne unit are connected by the cable 8. In the illustrated embodiment, the base 7 is placed at the tower 3, with a system that rotates around the tower according to the yaw position of the nacelle and rotor of the wind turbine, but it could also have a location at a distance from the wind turbine.

[0061] By extracting or retrieving the cable 8, the winch 9 rotates, and electrical energy is generated at the base 7 by a generator.

[0062] The cable 8 may be extracted and retrieved by means of movements of the airborne unit 6 which in this case is in the form of a kite. This will be described in further detail below. The energy generated by the airborne wind energy system is, according to this embodiment, transferred to the wind turbine 1 in the form of mechanical energy, where after it is transformed to electrical energy by the generator.

[0063] The kite 6 may be launched in a direction pointing away from the wind turbine blades 10, but collision may still be an issue relative to adjacent wind turbines of the wind park.

[0064] It can be seen that the kite 6 is launched to an altitude which is well above the wake created by the wind turbine 1. Furthermore, the wind speeds prevailing at this altitude are expected to be generally higher than the wind speeds prevailing at the altitude of the rotor 5 of the wind turbines 1. This provides a good utilisation of the available wind at the site of the wind turbines 1, and the total energy production of the site can thereby be increased as compared to a situation where airborne wind energy systems are not coupled to the wind turbines 1.

[0065] Typically, the kite 6 is able to move along specified movement paths.

[0066] FIG. 1b illustrates a wind park with a single wind turbine and an airborne wind energy system. In this embodiment the base of the airborne wind energy system is at the ground adjacent to the wind turbine.

[0067] FIG. 2 illustrates an embodiment, where the airborne unit is a glider or similar which is provided with rotors 11 which are capable of generating electrical energy locally at the airborne unit. The generated electrical energy is transferred to the base via an electrically conducting cable 12. The winch 12 is used for retrieving and launching of the glider.

[0068] Here the electrical energy is supplied to a suitable electrical component of the base 7.

[0069] FIG. 3 illustrates a wind park with a single multiple rotor wind turbine and an airborne wind energy system. The wind turbine 1 comprises four rotors 5, each mounted on an arm 13 mounted on the tower 3. Thus, the wind turbine 1 of FIG. 3 is a multirotor wind turbine.

[0070] An airborne wind energy system in the form of a kite 6 is mounted on the wind turbine 1 at the top of the tower 3, by means of a cable 8. Since the rotors 5 are mounted on the arms 13, at a distance from the tower 3, the wind turbine blades 10 are well clear of the mounting position of the kite 6. Accordingly, the risk of collisions between the wind turbine blades 10 and the kite 6 or the cable 8 is low. However, there remains a risk of collision, not least between the airborne energy system and adjacent wind turbines.

[0071] FIG. 4 illustrates the wind turbine from FIG. 3 but with a glider of the kind mentioned relative to FIG. 2.

[0072] FIG. 5a illustrates the wind park in FIG. 2 but with a plurality of wind turbines and airborne wind energy systems. In this embodiment the bases of the airborne wind energy systems are found at the nacelle of the wind turbines. This enables that the base yaw together with the rotor and nacelle of the wind turbine.

[0073] FIG. 5b illustrates a wind park with a plurality of wind turbines and airborne wind energy systems. In this embodiment the bases of the airborne wind energy systems are at the ground at a distance from the wind turbines.

[0074] FIG. 6 illustrates two wind turbines with a kite placed on an upfront wind turbine. The cable length which is part of the control parameters of the kite is below the distance to the wind turbine behind, or even below the distance including a safety margin.

[0075] A sphere 14 is defined by the length of the cable, and the sphere is divided into three different zones I, II, and III. There are the following rules for the zone: [0076] Zone I, position no 15. This could be considered as a green zone in which operation of the park is considered unproblematic, and a first, standard set of control parameters may be applied. I.e. the airborne unit is allowed to continue in its position while the wind turbine rotor rotates. Zone I may correspond to what herein is referred to as the first zone. [0077] Zone II, position no 16. This may be considered as a yellow zone in which a Warning is issued. In this zone a second set of control parameters may be applied due to the increased risk of collision, i.e. e.g. for bringing the airborne unit into zone I. Zone II may correspond to what herein is referred to as the second zone. [0078] Zone III, position no 17. This may be considered as a red zone in which an Alarm is issued. In this operation is not allowed, and a second set of control parameters may be applied for emergency stopping the operation of the wind turbine and/or for brining the airborne unit down. Zone III may correspond to what herein is referred to as the third zone.

[0079] FIG. 7 illustrates essentially the same zone definition illustrated in FIG. 6 but for the situation where the rope length is above the distance to the wind turbine behind/nearest wind turbine. An additional warning zone II is found above the wind turbine which is behind the airborne wind energy system.

[0080] FIG. 8 illustrates a wind park seen from above with an airborne wind energy system connected at one of the wind turbines. The height of the airborne unit is above the maximum blade tip height for the wind turbine including a safety margin. Zones I, II, and III in the same horizontal plane is illustrated. Of course one or more kites can be placed in a park and in such case, zones are made for each kite and further a method for preventing collision of kites with ropes are implemented.

[0081] FIG. 9 illustrates the view from FIG. 3 but for the situation where the height of the airborne unit is below the maximum blade tip height for the wind turbine (including the safety margin). Zones I, II, and III are in the same horizontal plane.

[0082] FIG. 10 illustrates a wind park seen from above with an airborne unit connected to a base within the wind turbine park. Zones I, II, and III are illustrated for the situation where the height of the airborne unit is below the maximum blade tip height of the wind turbine+a safety margin.

[0083] FIG. 11 illustrates an upwind wind turbine operating with yaw error and an airborne wind energy system connected to the wind turbine. The angle, alfa, is the angle between the rotor plane and the cable which connects the airborne unit to the base. The air borne unit will be in respectively zone I, II, or III depending on the value of alfa.