Energy storage system that can be attached to a wind turbine tower

Abstract

The invention relates to an energy storage system for wind turbines that can be attached inside the base of a wind turbine comprising a ventilation outlet in the nacelle (2). The energy storage system comprises a plurality of circular supports (4) with dimensions corresponding to the internal diameter of the tower (3) of the wind turbine (1) and which can be attached to the tower (3) at different heights. The system also comprises a plurality of energy storage modules (5) disposed on the circular supports (4), the energy storage modules (5) being connected to the electrical generation system and to the wind turbine control system. The energy storage system further comprises a door (6) in the wind turbine (1) with at least one air-inlet grate (7), which generates air flow towards the ventilation outlet of the nacelle (2), promoting the cooling of the energy storage modules (5).

Description

[0001] DESCRIPTION

[0002] ENERGY STORAGE SYSTEM IN ENERGY STORAGE SYSTEMS FOR WIND TURBINES

[0003] Technology sector

[0004] The present invention relates to wind turbines, and more specifically to an energy storage system inside them.

[0005] State of the art

[0006] Battery energy storage systems (BESS) are now widely used in wind farms. These systems store surplus energy generated by wind turbines in rechargeable batteries for future use, thus complementing the energy supplied to the grid and eliminating intermittency, ensuring energy supply and operational continuity. These systems require additional infrastructure, including dedicated buildings to house the batteries, which increase their visual impact, as well as the cabling networks that connect each wind turbine to the battery storage facility and then to the central substation. Furthermore, these systems (and others) require a well-designed cooling process, as they generate significant excess heat.Additionally, these facilities require special permits, which complicates the commissioning of wind farms and increases the complexity and costs of installation.

[0007] Given the disadvantages described for existing solutions, a solution is needed that eliminates these types of buildings while simplifying installation.

[0008] Object of the invention

[0009] In order to achieve this objective and solve the technical problems discussed so far, as well as provide additional advantages that may arise later, the present invention provides a modular energy storage system for wind turbines that can be fixed inside the base of wind turbines comprising a ventilation outlet in the nacelle.The system comprises a plurality of circular supports with dimensions corresponding to the inner diameter of the wind turbine tower and fixed to said tower at different heights, comprising a plurality of energy storage modules arranged on said circular supports, said battery modules being connected to the electrical generation system and the control system of the wind turbine, and the system comprising a wind turbine door with at least one air inlet grille that generates an airflow towards the nacelle ventilation outlet that promotes the cooling of the energy storage modules.

[0010] Thanks to this configuration, the need for additional buildings is eliminated, as it is integrated into the interior of the wind turbine tower itself, thus reducing the visual impact on the landscape and creating a more discreet environment for storing such expensive equipment, using the existing hollow space at the base of the tower.

[0011] Additionally, the same output transformer and main circuit breaker can be used, eliminating the need for additional wiring and civil works. This avoids the need for additional permits or applications, unlike existing buildings housing energy storage systems. This reduces installation complexity and costs.

[0012] Its modular configuration allows for increased storage capacity depending on the installation, forming packages of energy storage modules connected in series and in parallel for the required capacity.

[0013] The airflow generated by the system passively creates a flow between the door grilles and the ventilation outlet of the wind turbine nacelle. This airflow flows through the interior of the storage module ring, and the ventilation outlet is large enough to effectively cool the storage systems installed at the base of the turbine. This also allows for a more compact arrangement of the energy storage modules by dissipating the generated heat. This cooling airflow will be more efficient for wind turbines with forced ventilation within the nacelle itself. Activating a fan in the nacelle creates a suction effect, drawing in air from the door and generating active cooling.All these features also allow for its installation on existing wind turbines, so the system of the invention is adaptable to towers already built due to its core design and ease of assembly, using supports that will preferably be fixed to the tower by bolting, welding, or other fastening methods that facilitate installation and maintenance. Furthermore, air intake at the door of existing wind turbines is easily accessible.

[0014] Preferably, the modular energy storage system comprises control means configured for modulating the wind turbine's power output using the energy storage modules. This provides a more stable power output to the substation and improves the quality of the electricity supply.

[0015] According to one feature of the invention, the system comprises at least one fan between the nacelle's ventilation outlet and the storage modules, which forces airflow toward said ventilation outlet. This achieves improved cooling conditions for the energy storage modules, ensuring their operation and extending their lifespan.

[0016] According to another feature of the invention, some or all of the storage modules are provided to include at least one fan at their top for forced ventilation towards the nacelle's ventilation outlet. This improves the cooling of the electrical energy storage systems, either in addition to the previously described fan or independently.

[0017] Additionally, and preferably, the dimensions of each module will be smaller than the dimensions of the wind turbine door, thus facilitating installation and maintenance and enabling its implementation on existing wind turbines. Preferably, the circular supports will be divided into attachable parts whose dimensions also fit through the door, providing a system that is easily fixed to the inside of an existing wind turbine tower.

[0018] The invention also includes a configuration for the energy storage modules to remain operational if one module fails, allowing for independent module replacement. This facilitates the replacement of individual modules or module segments, simplifying maintenance. Furthermore, if one module fails, the entire system continues operating, providing a fail-safe system.

[0019] According to another feature of the invention, the energy storage modules are configured to use the same output transformer to the medium voltage grid and the same main switch of the wind turbine, thereby simplifying the electrical infrastructure and reducing costs.

[0020] The control systems are preferably configured to allow the wind turbine to operate in island mode without grid power. This configuration ensures compliance with LVRT and ZCRT voltage dip regulations. In the event of excess grid power generation or a grid fault, the wind turbine continues to operate to generate energy for storage.

[0021] According to another aspect, the invention relates to a wind turbine comprising an electrical energy storage system according to any one of the characteristics described above.

[0022] Description of the figures

[0023] Figure 1 shows a schematic perspective view of a wind turbine with a modular energy storage system of the invention, comprising a partial section for visualization of the energy storage modules, and where the cooling airflow has been indicated by arrows.

[0024] Figure 2 shows a perspective view of a detail of the system that is the subject of the invention installed inside the wind turbine tower of Figure 1.

[0025] Detailed description of the invention

[0026] The following section describes the invention, taking as a reference the figures mentioned above and focusing on some details not previously mentioned, which will help to interpret the scope of the claims in relation to the drawings. However, it will be evident to those skilled in the art that the present teachings can be implemented without such details or with a modification thereof that does not affect the extent defined by the claims. As can be seen in Figure 1, the energy storage system will be installed inside a wind turbine tower (3), at its base, in the practical example shown in the figures, with the energy storage modules corresponding to BESS-type batteries.Thus, as can be seen in Figure 2, a plurality of circular supports (4) will first be fixed, their diameter matching the inner diameter of the tower (3). These supports will be attached to the inside of the tower (3) by bolting, welding, or other fastening methods, arranged vertically. Preferably, these supports (4) will have maximum dimensions smaller than the dimensions of the entrance door (6) to the wind turbine tower (1). If these supports (4) exceed the dimensions of the door (6), they will be made up of interlocking parts, each of which will be smaller than the dimensions of the door (6).

[0027] Subsequently, the energy storage modules (5) will be installed. As shown in Figure 2, these modules have a rectangular cross-section or other configurations and will be arranged vertically in a ring, according to the diameter of the tower (3). Other arrangements of the energy storage modules (5) on the supports are also possible. Like the supports (4), the energy storage modules (5) are designed to have maximum dimensions smaller than the dimensions of the door. This will facilitate installation and maintenance by installing segments of energy storage modules (5) on each support (4).

[0028] This annular arrangement allows for the compact inclusion of energy storage modules (5) forming packages of modules connected in series and in parallel for the required capacity.

[0029] As shown in Figure 2, the system door (6) includes grilles (7) that allow air to enter. Thanks to the annular configuration, as indicated by the arrows in Figure 1, an airflow is generated between the grilles (7) and the nacelle's ventilation outlet (2). This allows for the installation of a more compact, high-capacity energy storage system without the generated heat affecting the system. The nacelle's ventilation outlet is designed to be sufficiently wide to allow for effective cooling of the storage system.

[0030] To reinforce said ventilation according to an alternative of the invention, the system is provided to include a fan (8) that promotes a forced flow of cooling air, increasing the cooling of the system and therefore its capacity.

[0031] According to another alternative of the invention, it is provided that alternatively or in conjunction with the fan (8), some or all of the modules (5) preferably comprise a fan (9) at the top, so that the modules (5) are cooled more effectively and the heat released is directed to the ventilation outlet of the gondola (2).

[0032] Additionally, the supports (4) will be in the form of a grid to promote ventilation.

[0033] Likewise, the storage systems will need an air inlet at the base of the tower (3) of the wind turbine (1), which this invention proposes to be made in the door (6) of the tower (3) in order to be implemented in existing wind turbines without the need to open air inlets in the structure of the tower (3) itself, whose structure is not designed for this, in contrast to the door (6) of the tower, which has a reinforcing frame that allows the door (6) to be modified to implement said air inlet.The air inlet made in the door (6) of the wind turbine must have a grid system (7) to protect the wind turbine from the entry of foreign elements, a filter to protect the wind turbine and the storage systems (5) from the entry of environmental dirt, and must have a heating system to prevent the air inlet from being blocked by snow, in which case it could pose a difficulty for the cooling system.

[0034] Regarding the electrical infrastructure, the storage modules (5) are preferably configured to use the same output transformer to the medium voltage network and the same main switch of the wind turbine (1), the system comprising control means that allow the wind turbine to work in island mode without network voltage, thus complying with the LVRT and ZVRT voltage dip regulations.

Claims

CLAIMS 1.- Energy storage system for wind turbines, fixable inside the base of wind turbines comprising a ventilation outlet in the nacelle (2), comprising a plurality of circular supports (4) with dimensions corresponding to the inner diameter of the tower (3) of the wind turbine (1) and fixable to said tower (3) at different heights, comprising a plurality of energy storage modules (5) arranged on said circular supports (4), said energy storage modules (5) being connected to the electrical generation system and the control system of the wind turbine, and the system comprising a door (6) of the wind turbine (1) with at least one air inlet grille (7) that generates an airflow towards the ventilation outlet of the nacelle (2) that promotes the cooling of the energy storage modules (5). 2.- Energy storage system according to the previous claim, comprising control means configured for modulating the power of the wind turbine by means of the energy storage modules (5). 3.- Energy storage system according to any one of the preceding claims, comprising at least one fan (8) between the ventilation outlet of the nacelle (2) and the energy storage modules (5) for forced ventilation. 4.- Energy storage system according to any one of the preceding claims, comprising at least one fan (9) on the top of the battery module (5) for forced ventilation towards the ventilation outlet of the nacelle (2).

5. Energy storage system according to any one of the preceding claims, wherein the door (6) of the wind turbine (1) is heated to prevent the air inlet from being blocked by snow aeration. 6.- Energy storage system according to any one of the preceding claims, wherein the air inlet grilles (7) comprise grilles and / or filters for protecting the interior of the wind turbine (1). 7.- Energy storage system according to any one of the preceding claims, wherein the dimensions of each energy storage module (5) are smaller than the dimensions of the door (6) of the wind turbine (1).

8. Energy storage system according to any one of the preceding claims, wherein the energy storage modules (5) are configured to continue operating if one module fails, and allow for independent module replacement. 9.- Energy storage system according to any one of the preceding claims, wherein the energy storage modules (5) are configured to use the same output transformer to the medium voltage network and the same main switch of the wind turbine (1).

10. Energy storage system according to any one of the preceding claims, wherein the control means are configured to allow the wind turbine (1) to operate in island mode without grid voltage. 11.- Wind turbine comprising an energy storage system according to any one of the preceding claims.

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