Method for assembling a blade and a counterweight

Abstract

The invention relates to a method for assembling blades and counterweights on a direct drive wind turbine, characterized in that the blades (3) and the passive counterweights (4) or active counterweights (9) are lifted and lowered vertically from the ground to the hub (2) by means of a cable (5) which is controlled by a lifting and lowering mechanism arranged in the hub (2). The invention is also characterized in that the assembly method is combined with the self-lifting system of the wind turbine. First, the tower section (1), the nacelle, the rotor (2) and the counterweights (4, 9) are installed before the lifting assembly, then the new tower section is introduced through the bottom part in order to complete the installation of the blades (3) in three successive steps.

Description

Technical Field

[0001] The present invention relates to a method for assembling blades without the use of a large auxiliary crane, and to a counterweight for maintaining rotor balance during the assembly process. Background Technology

[0002] The assembly of a wind turbine begins with the erection of the tower, followed by the installation of the nacelle and hub, and finally the installation of the blades. As the blades are installed one by one, an imbalance is created in the rotor. To counteract this imbalance, counterweights are used, and the rotor is rotated to position the successive blades (usually with the aid of an auxiliary crane).

[0003] Existing technologies disclose different solutions for using counterweights.

[0004] Patent WO03012291A1 discloses a method of mounting three counterweights on a hub, with one counterweight positioned laterally, which is then removed and a first blade installed. The rotor rotates until another counterweight is in a laterally positioned position, and it is replaced again by the blade. Assembly is performed using the same procedure. The counterweights are formed by different masses that can be added or removed, ensuring that the combined torque acting on the rotor is always zero.

[0005] Patent WO2014076825A1 discloses the initial installation of a counterweight and blades. The counterweight is hinged, and its center of gravity is positioned along the circumferential direction of the rotor by moving its mass and rotating the rotor. A second blade is then attached. The counterweight comprises a movable internal mass and a hydraulically articulated joint system.

[0006] Further developments are disclosed in US2016090962A1, US2019085818A1, and CN114321276A, in which the counterweight includes an articulated structure, a telescopic beam, or a refillable tank for adjusting mass.

[0007] A common feature of blade assembly using counterweights in existing technologies is that the blades are installed in a horizontal position with the aid of an auxiliary crane.

[0008] Lifting the blades in direct-drive wind turbines remains an unsolved technical problem, as the rotor cannot rotate freely during assembly and it is neither possible nor desirable to use large auxiliary cranes. Summary of the Invention

[0009] The object of this invention is to develop a method for mounting blades of a "direct-drive" wind turbine using counterweights and a blade lifting and lowering system located inside the hub.

[0010] For this purpose, the counterweights and blades are arranged on the ground adjacent to the wind turbine tower.

[0011] Using a lifting system located inside the hub and cables passing through an opening (where the blade roots are anchored), the counterweight and blade are lifted.

[0012] Each time an element is lifted, the hub rotates, causing the new blade openings to be correctly oriented in the lower horizontal position for subsequent lifting operations.

[0013] First, the counterweights are added, each consisting of steel supports and concrete blocks.

[0014] Then, the blades are lifted, and when the second and third blades are lifted, their corresponding counterweights are reduced.

[0015] Active counterweights can also be used, which change the rotor's center of gravity via a hinged joint. Counterweights can also be used in such a way that the mass is formed by a reservoir that can be filled with liquid, in order to change the rotor's balance.

[0016] Using this active counterweight can reduce their number and the number of assembly steps.

[0017] All lifting operations are performed vertically, without the use of large external cranes.

[0018] This method offers the following advantages in particular:

[0019] - The assembly is carried out in wind conditions of up to 15 m / s, compared to the fact that the complete rotor assembly of this type of "direct drive" wind turbine is limited to wind speeds of 7-9 m / s.

[0020] - Reduce costs associated with cranes and auxiliary equipment. Attached Figure Description

[0021] A brief description of a series of accompanying drawings is given below to better understand the invention and specifically relates to embodiments of the invention provided as non-limiting examples.

[0022] Figure 1 This indicates the assembly stage using two passive counterweights.

[0023] Figure 2 This diagram illustrates the passive counterweight.

[0024] Figure 3 This indicates the assembly stage using a single active counterweight.

[0025] Figure 4 This illustrates a practical example of a passive counterweight installed on the ground before the wind turbine self-lifts.

[0026] Figure 5 This illustrates another practical embodiment where the active counterweight is installed on the ground prior to self-lifting. Detailed Implementation

[0027] like Figure 1 As shown, the wind turbine includes a tower 1, a nacelle, and a hub 2. Blades 3 are added to the hub 2 to complete the assembly.

[0028] The blades 3 are installed one after another, and due to their weight, an imbalance is created in the hub 2 as the rotor rotates. To counteract this imbalance, a counterweight 4 is used during assembly, and the hub 2 rotates to position the successive blades 3. All components are initially arranged on the ground near the tower 1.

[0029] The method includes the following steps:

[0030] - A blade lifting / lowering system with a hoist and cable is installed inside hub 2.

[0031] - The lifting / lowering system lifts the first counterweight 4, which is fixed to the wheel hub 2 at a 180° position.

[0032] - Use a wind turbine generator or a special tool mounted on the wind turbine shaft to rotate hub 2 until counterweight 4 is positioned at an angle of 300° and secured by the rotor locking system.

[0033] - Raise the second counterweight and fix it at the 180° position, so that the hub 2 rotates another 120°, so that the hub opening is in the lower horizontal position.

[0034] - The lifting / lowering system includes cable 5, which is anchored to the root of the blade and vertically lifts the blade.

[0035] - Once the first blade 3 is fixed, the hub rotates 120° and lowers the first counterweight 4 so that the hub opening with the fixed counterweight is in a lower horizontal position. Then the second blade 3 is raised and fixed to the rotor.

[0036] - Repeat the process of rotating the hub, lowering the counterweight, and lifting the third blade to complete the blade assembly in three consecutive steps.

[0037] like Figure 2 As shown, the counterweight 4 includes a steel metal support 6 with two ends: one end is provided with an anchoring device 7 for fixing to the hub 2, and the opposite end is provided with a mass 8 in the form of a block, which is preferably made of concrete.

[0038] like Figure 3 As shown, in an alternative embodiment, the two passive weights 4 are replaced by a single active weight 9.

[0039] The active counterweight 9 includes a metal structure 6 with a hinge joint 10 and an active element that allows the hinge joint to move during assembly in order to balance the rotor's center of gravity.

[0040] The method includes:

[0041] - Raise the active counterweight 9 and fix it to the wheel hub 2 at the 180° position.

[0042] -The counterweight 9 is moved by its hinge joint 10 and the hub 2 is rotated until the counterweight 9 is positioned at an angle of 300° and the rotor is locked.

[0043] - Lift the first blade 3 to rotate the hub 2 by 120°, and lift the second blade 3.

[0044] - Return the active counterweight 9 to its initial straight position, rotate the hub 120°, and lower the counterweight 9 while raising the third blade 3.

[0045] In another embodiment, the mass 8 of the counterweights 4 and 9 is formed by a refillable reservoir that can be filled with either a fluid or solid mass portion to alter the rotor's balance.

[0046] Figure 4 and 5 The assembly process is described, in which a self-lifting system is used to raise the first tower section 1, the nacelle and the hub 2, and additional tower sections are introduced from below until the final tower is completed.

[0047] like Figure 4 As shown, two passive counterweights 4 are installed simultaneously with the first tower section 1, the nacelle, and the hub 2 using a small auxiliary crane. These counterweights 4 do not interfere with the self-lifting system surrounding the initial assembly and raise the assembly thus formed, in which the new tower section 1 is inserted from below.

[0048] like Figure 5 As shown, the active counterweight 9 is installed and rotates simultaneously with the first tower section 1, the nacelle, and the hub 2. This counterweight 9 does not interfere with the self-lifting system and raises the resulting components, in which the new tower section 1 is inserted from below.

[0049] Once the wind turbine assembly is complete, blade 3 is lifted, as in... Figure 1 and 3 As explained in the text.

Claims

1. A method for mounting blades and counterweights onto a hub (2) of a wind turbine supported on a tower (1) or a first tower section (1), the hub comprising an internal lifting / lowering system, a rotating device, and a rotor locking system, characterized in that: - Before starting the installation of blades (3), install at least one counterweight (4, 9) to balance the rotor in the subsequent assembly stage; -Use the cable (5) through the internal lifting / lowering system that passes through the blade root opening to install the blade (3) vertically from the ground, and complete the assembly in three consecutive steps; - Each time the blade (3) is installed, the hub (2) is rotated 120° using a wind turbine generator or a special tool mounted on the wind turbine shaft and secured by a rotor locking system; - When the counterweights (4, 9) are positioned at 180°, the counterweights are vertically lowered using the cable (5) of the internal lifting / lowering system before the new blade (3) is lifted in lifting mode using the internal lifting / lowering system.

2. The method for assembling blades and counterweights according to claim 1, wherein: Using two counterweights (4), the first counterweight is installed, the hub (2) is rotated 120°, and the second counterweight is installed. The hub is rotated another 120° before the blade installation begins. Each counterweight includes a steel metal support (6), one end of which is provided with an anchoring device (7) for fixing to the hub (2), and the opposite end is provided with a block mass (8).

3. The method for assembling blades and counterweights according to claim 1, wherein: Using a single counterweight (9), the counterweight includes a metal support (6) with a hinge joint (10) and an active element configured to move the hinge joint during assembly to balance the center of gravity of the rotor. One end of the counterweight is provided with an anchoring device (7) for fixing to the hub (2), and the opposite end is provided with a block mass (8). Once installed, the counterweight (9) is hinged and rotated 120° to begin the installation of the blades (3).

4. The method for assembling blades and counterweights according to any one of the preceding claims, wherein: The mass (8) is formed by a reservoir that can be filled with liquid to change the balance of the rotor.

5. The method for assembling blades and counterweights according to any one of the preceding claims, wherein: During the assembly of the first tower section (1), nacelle and hub (2), a counterweight is installed using an auxiliary crane, and then a self-lifting system is installed around the assembly without interfering with the counterweight (4, 9). The assembly is lifted while a new tower section is introduced from below, and then the hub (2) is rotated and the blades (3) are installed in three consecutive steps.

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