Foil coil leading-out structure and offshore wind power transformer

Abstract

The utility model discloses a foil coil leading-out structure which comprises a strip-shaped copper bar, the copper bar is divided into a connecting part and a leading-out part in the length direction, the surface of the connecting part is attached to the foil surface of a foil coil, and the leading-out part extends out of the foil from the connecting part and serves as a leading-out end of the foil coil. A through groove penetrating through the copper bar in the thickness direction is formed in the connecting part, and the other outer edges of the connecting part except the joint of the connecting part and the leading-out part and the inner edge of the through groove are welded to the surface of the connecting foil. The foil coil leading-out structure can effectively improve the contact area of coil leading-out and the temperature rise condition at the welding position. The utility model further provides an offshore wind power transformer.

Description

Technical Field

[0001] This utility model specifically relates to a foil-wound coil lead-out structure and an offshore wind power transformer. Background Technology

[0002] In the field of offshore wind turbine nacelle transformer technology, in order to increase the installed capacity of offshore wind power and reduce the cost of offshore wind turbines, the capacity of a single transformer has been increasing, from the original 4500kVA to 11000kVA, 12500kVA, 16000kVA, and 18000kVA specifications. Common voltage specifications are 0.69kV, 1.14kV, and 1.35kV. Based on the transformer capacity and voltage-current conversion, the low-voltage current needs to be around 6000A to 10000A. Such a large current places a significant challenge on the current-carrying capacity of the low-voltage coil.

[0003] The low-voltage coil structure commonly used in wind power products employs copper or aluminum foil winding, i.e., foil-wound coils or foil-type coils. The coil's input and output leads are led out using copper busbars, which are welded to the copper / aluminum foil. During transformer operation, due to the large current, the welded joint between the copper busbar and the copper / aluminum foil often experiences overheating due to the small weld fusion area. Even small amounts of overheating can easily cause transformer oil decomposition, producing harmful gases such as ethane and acetylene. Increased overheating can lead to the copper busbar melting due to high temperatures, or even the copper foil burning through and causing a short circuit, resulting in a quality accident. Utility Model Content

[0004] The technical problem to be solved by this utility model is to address the aforementioned shortcomings in the prior art by providing a foil-wound coil lead-out structure, which can effectively improve the contact area of ​​the coil lead-out and the temperature rise at the welding position. This utility model also provides an offshore wind power transformer.

[0005] This utility model provides a foil-wound coil lead-out structure, including a strip-shaped copper busbar. The copper busbar is divided into a connecting part and a lead-out part along its length. The surface of the connecting part is attached to the foil surface of the foil-wound coil. The lead-out part extends outward from the connecting part and serves as the lead-out end of the foil-wound coil. A through groove penetrating the thickness direction of the copper busbar is formed on the connecting part. The outer edge of the connecting part, except for the joint with the lead-out part, and the inner edge of the through groove are all welded to the foil surface.

[0006] Furthermore, the through slot is opened along the length of the copper busbar, starting from the junction of the connecting part and the lead-out part, and extending as a continuous slot occupying two-thirds of the total length of the connecting part.

[0007] Furthermore, the width of the through groove is 4mm to 8mm.

[0008] Furthermore, the foil-wound coil lead-out structure also includes a support curtain, which is placed between the iron core and the copper busbar located in the inner ring after the foil is wound. The support curtain has a channel along the axial direction of the iron core to serve as a heat dissipation channel for cooling oil.

[0009] Furthermore, one side surface of the support strip curtain is attached to the steel tension plate on the iron core, and the other side surface is provided with multiple protrusions. Each protrusion is arranged parallel to each other and spaced apart, and is arranged along the axial direction of the iron core and attached to the copper busbar, so that the gap between two adjacent protrusions together with the copper busbar forms the channel.

[0010] Furthermore, the support strip curtain is inserted and secured between the copper busbar and the steel tension plate in a tight fit manner.

[0011] Furthermore, the support strip curtain is made of cardboard.

[0012] Furthermore, the foil-wound coil lead-out structure also includes wedge-shaped support bars. There are two wedge-shaped support bars, both arranged along the axial direction of the iron core. They are respectively inserted into the two areas enclosed by the cylindrical part formed by the iron core, the support bar curtain and the foil material, and press against the support bar curtain from both sides to restrict the movement of the support bar curtain.

[0013] This utility model also provides an offshore wind power transformer, including a low-voltage winding unit, wherein the coil of the low-voltage winding unit is a foil-wound coil, and the lead-out structure of the foil-wound coil is the aforementioned foil-wound coil lead-out structure.

[0014] This utility model's foil-wound coil lead-out structure features a through-groove extending through the thickness of the copper busbar at the connecting portion. The outer edges of the connecting portion and the inner edges of the through-groove are welded to the foil surface. Compared to traditional lead-out copper busbar and foil connections where only one edge (usually a single edge) is welded, this lead-out structure welds both sides, one end, and the inner edge of the through-groove after the copper busbar and foil are bonded together. This fills the gap between the copper busbar and foil, firmly bonding them into a single unit, increasing connection strength, and resisting electrodynamic tearing of the weld. Furthermore, the significantly increased welding contact area optimizes temperature rise, preventing overheating due to a small contact surface. This further mitigates the potential for harmful gas emissions, copper busbar melting, foil burn-through, and short circuits caused by overheating. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the connection structure between the copper busbar and the foil material in Embodiment 1 of this utility model;

[0016] Figure 2 This is a cross-sectional schematic diagram of the foil-wound coil lead-out structure installed on the coil in Embodiment 1 of this utility model.

[0017] In the diagram: 1. Copper busbar; 11. Connecting part; 12. Lead-out part; 13. Through groove; 2. Foil material; 3. Supporting strip curtain; 31. Channel; 32. Raised strip; 4. Iron core; 41. Steel tension plate; 5. Wedge-shaped support strip. Detailed Implementation

[0018] The technical solutions of this utility model will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this utility model. All other embodiments obtained by those skilled in the art based on the embodiments of this utility model without creative effort are within the scope of this utility model.

[0019] In the description of this utility model, it should be noted that the terms "upper" and "lower" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience and simplification of the description and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0020] In the description of this utility model, the terms "first", "second", and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0021] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "connection," "setting," "installation," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0022] Example 1

[0023] The foil-wound coil lead-out structure of this embodiment can be used in the field of oil-immersed transformer technology. Specifically, it can be applied to the low-voltage winding of offshore wind power transformers as a heat dissipation structure for the low-voltage, high-current foil-wound coil lead-out copper busbar of offshore wind power transformers.

[0024] like Figure 1As shown, the foil-wound coil lead-out structure includes a strip-shaped copper busbar 1. The copper busbar 1 is divided into a connecting part 11 and a lead-out part 12 along its length. The surface of the connecting part 11 is attached to the surface of the foil material 2 of the foil-wound coil. The lead-out part 12 extends outward from the connecting part 11 to the foil material 2 as the lead-out end of the foil-wound coil. A through groove 13 penetrating the thickness direction of the copper busbar 1 is opened on the connecting part 11. The outer edges of the connecting part 11, except for the joint with the lead-out part 12, and the inner edge of the through groove 13 are all welded to the surface of the foil material 2.

[0025] Compared to the traditional connection method where only one edge (usually a single edge, such as the left edge) is welded to the copper busbar and foil, this lead-out structure connects the copper busbar 1 and the foil 2 by bonding the two sides, one end edge, and the inner edge of the through groove (i.e., Figure 1 The copper busbar 1 and the foil 2 are welded on all four sides (left, bottom, right and middle slots) shown in the figure. The weld fills the gap between the copper busbar 1 and the foil 2, which not only firmly bonds the copper busbar 1 and the foil 2 into a whole and improves the connection strength, but also improves the resistance of the weld to tearing by electrodynamic force. Furthermore, the significantly increased welding contact area optimizes the temperature rise and avoids overheating problems caused by small contact area. This further avoids the production of harmful gases, melting of the copper busbar 1, and short circuit caused by burning through the foil 2 that may be caused by overheating.

[0026] In this embodiment, the larger weld contact fusion surface leads to optimized temperature rise, making this lead-out structure more suitable for low-voltage, high-current windings, such as the foil-wound coils used in offshore wind turbine nacelle transformers. In this embodiment, the coil foil 2 can be made of copper foil, and the welding method can be the conventional welding method currently used for copper busbars in foil-wound coils.

[0027] In this embodiment, the through slot 13 is opened along the length of the copper busbar 1, extending from the junction of the connecting portion 11 and the lead-out portion 12, forming a continuous slot that occupies two-thirds of the total length of the connecting portion 11. Since the current density of the coil copper busbar 1 on the foil 2 is trapezoidally distributed, such as... Figure 1 As shown, the current density is greater closer to the upper part of the copper busbar 1 lead-out end (lead-out part 12) on the connecting part 11, and smaller closer to the lower part of the lead-out copper busbar 1. In this embodiment, the middle through groove 13 at the upper 2 / 3 of the connecting part 11 of the copper busbar 1 serves as a welding groove, which ensures a large welding contact fusion area for the high current part of the copper busbar 1, while reducing the amount of processing and welding work.

[0028] In this embodiment, the width of the through groove 13 is 4mm to 8mm. This width range can provide sufficient welding space to ensure an increased welding fusion area, while also ensuring the structural strength of the copper busbar 1 and the stability of its connection with the foil 2.

[0029] In this embodiment, as Figure 2As shown, the foil-wound coil lead-out structure also includes a support curtain 3. The support curtain 3 is placed between the iron core 4 and the copper busbar 1 located in the inner ring after the foil 2 is wound. That is, one end of the low-voltage coil formed after the foil 2 is wound and attached to the iron core 4 (as end a, b, c) is connected to a copper busbar 1, and the outermost end (as end x, y, z) is connected to a copper busbar 1. The support curtain 3 is placed between the iron core 4 and the copper busbar 1 (ends a, b, c). A channel 31 is opened on the support curtain 3 along the axial direction of the iron core 4 to serve as a heat dissipation channel for cooling oil. That is, after the low-voltage copper busbar 1 and the coil copper foil are wound into a multi-layer foil-type low-voltage coil part, the low-voltage coil part, which is in the shape of a cylinder, is fitted onto the transformer iron core 4, and the heat dissipation channel support curtain 3 is inserted between the low-voltage copper busbar 1 and the iron core 4 (the steel pull plate 41 on it). The channel 31 on the support curtain 3 provides a heat dissipation channel for the cooling oil at the bottom of the transformer, thereby carrying away local heat from the copper busbar 1 as it flows through the channel 31, further optimizing the temperature rise of the lead-out structure. In this embodiment, the support curtain 3 is made of cardboard, specifically heat-resistant cardboard with Class E insulation can be selected.

[0030] In this embodiment, as Figure 2 As shown, an insulating plate is provided between the iron core 4 and the steel tension plate 41. One side surface of the support curtain 3 is attached to the steel tension plate 41 on the iron core 4, and the other side surface is provided with multiple protrusions 32. Each protrusion 32 is arranged parallel to each other and spaced apart, and is arranged along the axial direction of the iron core 4, and is attached to the copper busbar 1, so that the gap between two adjacent protrusions 32 and the copper busbar 1 together form a channel 31. This structure ensures that there is a cooling oil heat dissipation channel 31, while avoiding the need for long holes, simplifying the processing process, and reducing the manufacturing difficulty and cost of the support curtain 3.

[0031] In this embodiment, the support curtain 3 is inserted and secured between the copper busbar 1 and the steel tension plate 41 in a tight fit manner. That is, during the design and production process, when the coil and iron core 4 are assembled, pressure is applied to insert the support curtain 3 between the copper busbar 1 and the steel tension plate 41 of the iron core 4. This prevents the support curtain 3 from moving or misaligning during assembly and operation.

[0032] In this embodiment, the foil-wound coil lead-out structure also includes a wedge-shaped support bar 5, such as... Figure 2 As shown, there are two wedge-shaped support bars 5, both arranged along the axial direction of the iron core 4. They are respectively inserted into the two areas enclosed by the cylindrical part formed by the iron core 4, the support bar curtain 3 and the foil 2, and are pressed against the support bar curtain 3 from both sides to restrict the movement of the support bar curtain 3. Figure 2 The wedge-shaped support bar 5 is simultaneously inserted into the gap between the copper foil and the iron core 4 on the left and right sides of the heat dissipation oil channel support bar curtain 3, restricting the left and right movement of the support bar curtain 3.

[0033] In general, the foil-wound coil lead-out structure of this embodiment employs slotted welding at the upper two-thirds of the connection between the low-voltage lead-out copper busbar 1 and the low-voltage copper foil. Specifically, four-sided welding is used between the low-voltage lead-out copper busbar 1 and the low-voltage copper foil to increase the contact area between the copper busbar 1 and the copper foil. This not only improves the connection structure between the coil lead-out copper busbar 1 and the copper foil but also ensures sufficient fusion area when the low-voltage coil is subjected to high current. Furthermore, it provides an oil flow channel to improve heat dissipation at the welded connection between the copper busbar 1 and the copper foil. This solves the problem of overheating caused by the small welded fusion area at the welded connection between the copper busbar 1 and the copper foil under high current.

[0034] Example 2

[0035] The offshore wind power transformer of this embodiment includes a low-voltage winding unit. The coil of the low-voltage winding unit is a foil-wound coil, and the lead-out structure of the foil-wound coil is the foil-wound coil lead-out structure in Embodiment 1.

[0036] During transformer operation, the low-voltage lead-out copper busbar 1 is welded to the copper foil on four sides, which increases the welding contact area and avoids overheating problems caused by a small contact area. It also improves tear resistance, preventing strong electrodynamic forces from tearing the weld seam due to high current. An oil channel support curtain 3 is added between the copper busbar 1 and the steel tie plate 41 of the iron core 4, forcing the lower cooling oil to flow through the welding surface of the copper busbar 1 and the copper foil, carrying away a large amount of heat generated by overheating due to welding quality. This greatly improves the operational stability of the high-current foil-wound coil.

[0037] It is understood that the above embodiments are merely exemplary implementations used to illustrate the principles of this utility model, and the utility model is not limited thereto. For those skilled in the art, various modifications and improvements can be made without departing from the spirit and essence of this utility model, and these modifications and improvements are also considered to be within the protection scope of this utility model.

Claims

1. A foil coil wire leading structure, characterized by: It includes a strip-shaped copper busbar (1), which is divided into a connecting part (11) and a lead-out part (12) along its length. The surface of the connecting part (11) is attached to the surface of the foil (2) of the foil-wound coil. The lead-out portion (12) extends outward from the connecting portion (11) toward the foil (2) and serves as the lead-out end of the foil-wound coil. The connecting part (11) has a through groove (13) that runs through the thickness direction of the copper busbar (1). The outer edge of the connecting part (11) except for the joint with the lead-out part (12) and the inner edge of the through groove (13) are all welded to the surface of the foil (2).

2. The foil-wound coil lead-out structure according to claim 1, characterized by: The through slot (13) is opened along the length of the copper busbar (1), starting from the junction of the connecting part (11) and the lead-out part (12), and is a continuous slot that accounts for two-thirds of the total length of the connecting part (11).

3. The foil-wound coil lead-out structure according to claim 1, characterized by: The width of the through groove (13) is 4mm to 8mm.

4. The foil-wound coil lead-out structure according to claim 1, characterized by: It also includes a support curtain (3), which is placed between the iron core (4) and the copper busbar (1) located in the inner circle after the foil (2) is wound. The support curtain (3) has a channel (31) along the axial direction of the iron core (4) to serve as a heat dissipation channel for cooling oil.

5. The foil-wound coil lead-out structure according to claim 4, characterized in that: One side surface of the support curtain (3) is attached to the steel tension plate (41) on the iron core (4). On the other side surface, there are multiple protrusions (32), each protrusion (32) is arranged parallel to each other and is arranged along the axial direction of the iron core (4), and is attached to the copper busbar (1) so that the gap between two adjacent protrusions (32) together with the copper busbar (1) forms the channel (31).

6. The foil-wound coil lead-out structure according to claim 5, characterized by: The support curtain (3) is inserted and secured between the copper busbar (1) and the steel pull plate (41) in a tight fit manner.

7. The foil-wound coil lead-out structure according to claim 4, characterized by: The support curtain (3) is made of cardboard.

8. The foil-wound coil lead-out structure according to claim 4, characterized by: It also includes wedge-shaped struts (5), Two wedge-shaped support bars (5) are provided, both arranged along the axial direction of the iron core (4). They are respectively inserted into the two areas enclosed by the cylindrical part formed by the iron core (4), the support bar curtain (3) and the foil (2), and are pressed against the support bar curtain (3) from both sides to restrict the movement of the support bar curtain (3).

9. A marine wind power transformer, characterized in that It includes a low-voltage winding unit, wherein the coil of the low-voltage winding unit is a foil-wound coil, and the lead-out structure of the foil-wound coil is the foil-wound coil lead-out structure as described in any one of claims 1 to 8.

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