High-voltage-class dry-type transformer for offshore wind power

Abstract

The invention relates to a high-voltage-class dry-type transformer for offshore wind power, which comprises a cable-stayed support frame and a multi-phase transformer body which is clamped and fixed through an upper clamping piece and a lower clamping piece, and is characterized in that the transformer body comprises an iron core, and a low-voltage coil, an insulating cylinder and a high-voltage coil group which are sequentially arranged on a core column of the iron core from inside to outside in a sleeving manner; wherein the high-voltage coil group comprises an upper high-voltage coil and a lower high-voltage coil which are connected through a coil connecting plate, a top support is arranged on the upper clamping piece, a supporting foot pad is arranged on the lower side of the lower clamping piece, the upper end of the cable-stayed supporting frame is connected with the corresponding top support, and the lower end of the cable-stayed supporting frame is connected with the corresponding supporting foot pad. Relative displacement between the upper high-voltage coil and the lower high-voltage coil can be avoided, and meanwhile, the transformer is more stable in installation and fixation and better in heat dissipation performance.

Description

Technical Field

[0001] The invention relates to the technical field of transformers, in particular to a high-voltage dry-type transformer for offshore wind power. Background Art

[0002] As wind farm capacity gradually increases and develops toward deep sea, 66kV and higher voltage dry-type transformers for offshore wind power have become the preferred solution for improving the power generation and transmission efficiency of offshore wind power and reducing the overall investment cost of offshore wind power.

[0003] However, due to the limitation of the size of the cabin or tower itself, there are strict requirements on the volume and weight of transformer parts. In the early offshore wind power transformers, the coils were usually integrated with each other. With the development of technology, the coils of the existing offshore wind power transformers are usually split into two upper and lower structures to facilitate the coils to enter and exit the tower, and the coils are connected or rigidly connected by intermediate pads. For example, the patent CN102064005B discloses a new type of dry-type transformer for offshore wind power that can be maintained. The low-voltage coil of each phase of the transformer is axially split to form two independent low-voltage foil coils, which are respectively sleeved on the upper and lower parts of the corresponding iron core column. The high-voltage coil of each phase is axially split to form two independent high-voltage segmented coils, which are respectively sleeved on the upper and lower parts of the corresponding iron core column. The low-voltage foil coil and the high-voltage segmented coil sleeved on the upper part of the same iron core column form three upper windings, and the low-voltage foil coil and the high-voltage segmented coil sleeved on the lower part of the same iron core column form three lower windings. Four epoxy resin pads are arranged between each upper winding and the corresponding lower winding. However, under impact tests, it was found that the connection structure in the middle of the coil could not provide sufficient friction to resist the impact force, and there was a risk of displacement between the upper and lower coils.

[0004] In addition, in order to adapt to the harsh climate and environmental conditions at sea, dry-type transformers for offshore wind power mostly use air-water cooling, that is, the transformer room and the outside air indirectly exchange heat through a cooling system. For example, the CN202282228U patent discloses a dry-type transformer for offshore wind power with a heat exchange device (i.e., a cooling system). Therefore, the offshore transformer shell has a high protection level, and is required to have efficient heat dissipation and vibration resistance. Existing offshore wind power transformers often install trapezoidal frames at both ends of the transformer for support to reduce the displacement of the upper part of the transformer. However, as the transformer capacity gradually increases, the transformer width increases accordingly. The trapezoidal frames installed at both ends of the transformer have very little auxiliary support effect under the vibration state of the transformer. Under long-term vibration conditions, there is still a risk of connection failure between the transformer base and components. At the same time, for the coils of the upper and lower double split structure, this will further increase the risk of displacement between the upper and lower coils.

[0005] In addition, in the prior art, dry-type transformers for offshore wind power are easily affected by factors such as large insulation distance and multiple insulation partitions when operating in air-water cooling mode, which can easily lead to low heat dissipation efficiency. In order to solve the above-mentioned heat dissipation problem of offshore transformers, some other types of transformer heat dissipation structure designs have also appeared in the prior art. For example, the patent CN114898992A discloses a 66kV high voltage level, 10MVA large capacity offshore wind power dry-type transformer. The transformer divides the high-voltage coil part into an inner high-voltage coil and an outer high-voltage coil, and forms a cooling air duct between the inner high-voltage coil and the outer high-voltage coil for heat dissipation, but the coil as a whole is still an integrated structure from top to bottom. For example, the patent CN220474437U discloses an offshore wind power dry-type transformer with high efficiency in heat dissipation. The transformer is designed with an insulating air guide, which includes a first air guide shell and a second air guide shell arranged in the front-to-back direction, and an air guide channel is formed inside the insulating air guide, or the insulating air guide and the bottom wall of the accommodating cavity are enclosed to form an air guide channel. However, the transformer installs the insulating air guide on the transformer body, which actually increases the installation volume of the transformer body, and also brings certain difficulties to the stable support and fixation of the offshore transformer. Summary of the invention

[0006] The purpose of the present invention is to provide a high-voltage dry-type transformer for offshore wind power, which can ensure that there is no relative displacement between the upper high-voltage coil and the lower high-voltage coil, and at the same time, the installation and fixation of the transformer is more stable and the heat dissipation performance is better.

[0007] The objective of the present invention is achieved through the following technical solutions:

[0008] A high-voltage dry-type transformer for offshore wind power, comprising a diagonal support frame and a multi-phase body clamped and fixed by an upper clamp and a lower clamp, wherein the body comprises an iron core and a low-voltage coil, an insulating cylinder and a high-voltage coil group sequentially sleeved on the core column of the iron core from the inside to the outside, wherein the high-voltage coil group comprises an upper high-voltage coil and a lower high-voltage coil connected by a coil connecting plate, a top bracket is provided on the upper clamp, and a supporting pad is provided on the lower side of the lower clamp, the upper end of the diagonal support frame is connected to the corresponding top bracket, and the lower end is connected to the corresponding supporting pad.

[0009] The coil connection plate is made of silicone, and the lower side of the coil connection plate is bonded to the upper end surface of the lower high-voltage coil through room temperature vulcanized silicone rubber coating, and the lower end surface of the upper high-voltage coil is bonded to the upper side of the coil connection plate through room temperature vulcanized silicone rubber coating.

[0010] The coil connection plate is provided with a limiting groove, and the limiting groove cooperates with a limiting block provided on the lower end surface of the upper high-voltage coil.

[0011] The upper end of the inclined support frame is connected to the corresponding top bracket through a first connecting rod, and the lower end of the inclined support frame is connected to the corresponding supporting pad foot through a second connecting rod.

[0012] The inclined support frame is provided with a first connecting block and a second connecting block, and one end of the first connecting rod is fixed to the lower side of the top support, and the other end is fixed to the first connecting block, and one end of the second connecting rod is fixed to the supporting foot, and the other end is fixed to the second connecting block.

[0013] An insulating heat shrinkable sleeve is sleeved on the outer side of the main body of the inclined support frame.

[0014] A mounting plate is provided at the lower end of the inclined support frame, and the mounting plate is fixed on the corresponding supporting pad foot, and a hanging plate is provided on the upper clamp.

[0015] Both ends of the upper clamp are provided with rocker sealing boxes with fixed rocker arms inside, wherein the outer side of the rocker sealing box is connected to the transformer chamber shell, the head end of the fixed rocker arm extends to the outside of the rocker sealing box and is fixed, and the rear end of the fixed rocker arm is connected to the upper clamp.

[0016] Arc-shaped partitions are symmetrically arranged between the high-voltage coil groups of adjacent phases.

[0017] The insulating tube is a multi-layer structure, and the lower end of each single layer of the insulating tube is provided with a thickened portion, and the lower end gap between two adjacent layers of the insulating tube is blocked by the thickened portion.

[0018] The advantages and positive effects of the present invention are:

[0019] 1. The present invention connects the upper high-voltage coil and the lower high-voltage coil by bonding them together through a coil connecting plate made of silicone material, so that the air gap between the upper and lower coils and the coil connecting plate can be emptied, eliminating local discharge caused by the small air gap between the coils, ensuring insulation performance, and increasing the friction coefficient between the coils, thereby ensuring that the upper high-voltage coil and the lower high-voltage coil will not be relatively displaced under impact conditions.

[0020] 2. The present invention can provide a limiting groove on the coil connecting plate as needed, so as to further limit the rotation of the upper high-voltage coil relative to the lower high-voltage coil and ensure that the axis of the upper high-voltage coil is aligned with the axis of the lower high-voltage coil.

[0021] 3. The present invention installs a diagonal support frame in front of the transformer to ensure stable support. Compared with the traditional trapezoidal support frame structure formed at both ends of the transformer using channel steel and square steel pipes, the structure of the present invention saves more space and can be located closer to the center of gravity of the transformer, which can significantly reduce the risk of the transformer tipping over. At the same time, the present invention uses an insulating heat shrink tubing to further shorten the insulation distance from the live body.

[0022] 4. Both ends of the upper clamp of the present invention are provided with a rocker sealing box with a fixed rocker arm inside, and the present invention utilizes a fixed rocker arm to directly pass through the rocker sealing box and act on the transformer body to prevent it from moving left and right, thereby further improving the vibration stability of the transformer. At the same time, the rocker sealing box ensures the overall sealing of the transformer chamber shell.

[0023] 5. The present invention symmetrically arranges arc-shaped partitions between the high-voltage coil groups of adjacent phases, so that the cooling air entering from the lower end of the transformer will flow between the partition and the high-voltage coil group on the corresponding side, thereby enhancing the heat dissipation capacity of the coil surface. At the same time, the lower end gap between two adjacent layers of the insulating cylinder will be blocked by the thickened part, so that the cooling air can only enter from the lower end between the low-voltage coil and the insulating cylinder and between the insulating cylinder and the high-voltage coil group, thereby improving the heat dissipation efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a schematic diagram of the overall structure of the present invention,

[0025] Figure 2 for Figure 1 Schematic diagram of partition arrangement between two adjacent phase high voltage coil groups,

[0026] Figure 3 for Figure 1 Schematic diagram of the single-layer structure of the middle insulating cylinder.

[0027] Figure 4 for Figure 1 Schematic diagram of the structure of the middle coil connection plate.

[0028] Figure 5 for Figure 1 Structural diagram of the middle diagonal support frame.

[0029] Figure 6 for Figure 1 Schematic diagram of the structure of the fixed rocker arm and rocker arm sealing box.

[0030] Among them, 1 is the iron core, 2 is the low-voltage coil, 3 is the insulating tube, 301 is the thickened part, 4 is the upper high-voltage coil, 5 is the lower high-voltage coil, 6 is the coil connecting plate, 601 is the limiting groove, 7 is the partition, 8 is the supporting pad, 9 is the inclined support frame, 901 is the first connecting block, 902 is the second connecting block, 903 is the mounting plate, 10 is the upper clamp, 11 is the lower clamp, 12 is the hanging plate, 13 is the fixed rocker arm, 14 is the rocker arm sealing box, 15 is the top bracket, 16 is the second connecting rod, and 17 is the first connecting rod. DETAILED DESCRIPTION

[0031] The present invention will be further described below in conjunction with the accompanying drawings.

[0032] like Figures 1 to 6As shown, the present invention includes a multi-phase device body clamped and fixed by an upper clamp 10 and a lower clamp 11, and the device body includes an iron core 1 and a low-voltage coil 2, an insulating cylinder 3 and a high-voltage coil group which are sequentially sleeved on the core column of the iron core 1 from the inside to the outside, wherein the high-voltage coil group includes an upper high-voltage coil 4 and a lower high-voltage coil 5 connected by a coil connecting plate 6, and the coil connecting plate 6 is made of silicone. When the present invention is installed, the lower side of the coil connecting plate 6 is bonded to the upper end surface of the lower high-voltage coil 5 by room temperature vulcanized silicone rubber coating, and then the room temperature vulcanized silicone rubber is applied to the coil connecting plate 6. After the application, the lower end surface of the upper high-voltage coil 4 is placed on the coil connecting plate 6 and bonded. This method can empty the air gap between the upper and lower coils and the coil connecting plate 6, eliminate the local discharge caused by the small air gap between the coils, and connect the upper and lower coils as a whole, increase the friction coefficient between the coils, and ensure that the upper high-voltage coil 4 and the lower high-voltage coil 5 will not be relatively displaced under impact conditions under a certain clamping force of the upper and lower clamps.

[0033] like Figure 4 As shown, a limit groove 601 can be provided on the coil connecting plate 6 as needed, wherein the limit groove 601 can cooperate with the limit block provided on the lower end surface of the upper high-voltage coil 4 to further limit the rotation of the upper high-voltage coil 4 relative to the lower high-voltage coil 5, and ensure that it is aligned with the axis of the lower high-voltage coil 5.

[0034] like Figure 1 As shown, in this embodiment, an inclined support frame 9 is provided between the upper clamp 10 and the lower clamp 11, wherein the upper clamp 10 is provided with a top bracket 15, and the lower side of the lower clamp 11 is provided with a supporting foot 8, and the upper end of the inclined support frame 9 is connected to the corresponding top bracket 15, and the lower end is connected to the corresponding supporting foot 8.

[0035] like Figure 5 As shown, in this embodiment, the inclined support frame 9 is provided with a first connecting block 901 and a second connecting block 902, and the lower end of the inclined support frame 9 is provided with a mounting plate 903. Figure 1 As shown, the upper end of the inclined support frame 9 is connected to the corresponding top support 15 through the first connecting rod 17, and one end of the first connecting rod 17 is fixed to the lower side of the top support 15, and the other end is fixed to the first connecting block 901. The lower end of the inclined support frame 9 is connected to the corresponding support foot 8 through the second connecting rod 16, and one end of the second connecting rod 16 is fixed to the support foot 8, and the other end is fixed to the second connecting block 902. The mounting plate 903 at the lower end of the inclined support frame 9 is fixed to the corresponding support foot 8. The present invention forms two upper and lower triangular stable support structures through the first connecting rod 17 and the second connecting rod 16, thereby improving the support stability of the transformer.

[0036] In addition, in the present embodiment, the main body of the oblique-stayed support frame 9 is round steel, and an insulating heat shrinkable sleeve is mounted on the outside of the round steel. Compared with the traditional trapezoidal support frame structure formed at both ends of the transformer using channel steel and square steel pipes, the round steel structure of the oblique-stayed support frame 9 of the present invention saves more space in the transformer chamber and can be located closer to the center of gravity of the transformer. At the same time, the insulating heat shrinkable sleeve can be used to further shorten the insulation distance from the live body. The present invention has been verified through actual on-site installation. This oblique-stayed support frame 9 structure is installed on the front of the transformer, which can significantly reduce the risk of the transformer tipping over and greatly improve the installation stability of the offshore transformer.

[0037] like Figure 1 and Figure 6 As shown, in this embodiment, the upper clamp 10 is provided with a rocker sealing box 14 with a fixed rocker arm 13 inside at both ends, wherein the outer side of the rocker sealing box 14 is connected to the transformer chamber shell, the head end of the fixed rocker arm 13 extends to the outside of the rocker sealing box 14 and is fixed to the corresponding fixed structure outside the transformer chamber, and the rear end of the fixed rocker arm 13 is directly connected to the upper clamp 10 on the upper side of the transformer. In the prior art, in order to ensure the sealing of the transformer chamber shell, the structure of the upper clamp is often extended with a support plate at both ends, and the fixed rocker arm is installed on the support plate without being directly connected to the clamp, and then the whole seal is achieved by closing the area formed by the support plate shell. This structure greatly reduces the effect of transmitting the tension force received by the fixed rocker arm to the transformer body. In the present invention, the fixed rocker arm 13 passes through the rocker sealing box 14 and is directly connected to the upper clamp 10, so that the fixed rocker arm 13 can directly act on the transformer body to prevent it from moving left and right, thereby improving the vibration stability of the transformer, and the rocker sealing box 14 ensures the overall sealing of the transformer chamber shell.

[0038] like Figure 1 As shown, in this embodiment, a hanging plate 12 is provided on the upper clamp 10 for hoisting and transferring the transformer as a whole.

[0039] In addition, in order to solve the problem of low heat dissipation efficiency of dry-type transformers for offshore wind power due to factors such as large insulation distance and multiple insulation partitions under air-water cooling operation, the present invention also makes further improvements to the heat dissipation structure of the transformer, specifically:

[0040] like Figure 2 As shown, in this embodiment, arc-shaped partitions 7 are symmetrically arranged between the high-voltage coil groups of adjacent phases, so that the cooling air entering from the lower end of the transformer will flow between the partition 7 and the high-voltage coil group on the corresponding side, thereby enhancing the heat dissipation capacity of the coil surface.

[0041] In this embodiment, the insulating tube 3 is a multi-layer structure, and as Figure 3As shown, the lower end of each single layer of the insulating cylinder 3 is provided with a thickened portion 301, so that when the transformer is cooled, the lower end gap between two adjacent layers of the insulating cylinder 3 will be blocked by the thickened portion 301, thereby achieving the blocking of the air passage between adjacent layers of the insulating cylinder 3, so that the cooling air can only enter from the lower end between the low-voltage coil 2 and the insulating cylinder 3 and between the insulating cylinder 3 and the high-voltage coil group, and the cooling air will not enter the insulating cylinder 3, thereby improving the heat dissipation efficiency. The cooling air flows in from the lower end of the transformer is a well-known technology in the art, for example, see patents such as CN202282228U.

[0042] The working principle of the present invention is:

[0043] As the capacity of offshore wind power transformers gradually increases and their size becomes larger and larger, long-distance transportation and long-term low-frequency vibration in the tower and cabin are a great challenge to the stable operation of the transformer. The present invention connects the upper high-voltage coil 4 and the lower high-voltage coil 5 by bonding them together through a coil connecting plate 6 made of silicone material. This method can evacuate the air gap between the upper and lower coils and the coil connecting plate 6, eliminate local discharge caused by the small air gap between the coils, and ensure insulation performance. At the same time, the upper and lower coils are connected as a whole, which increases the friction coefficient between the coils. Under a certain clamping force of the upper and lower clamps, it can ensure that the upper high-voltage coil 4 and the lower high-voltage coil 5 will not be relatively displaced under impact conditions.

[0044] In addition, the present invention installs an inclined support frame 9 in front of the transformer to ensure stable support. Compared with the traditional trapezoidal support frame structure formed at both ends of the transformer using channel steel and square steel pipes, the round steel structure of the inclined support frame 9 of the present invention saves more space in the transformer chamber and can be located closer to the center of gravity of the transformer. At the same time, the insulating heat shrink tubing can be used to further shorten the insulation distance with the live body. The present invention has been verified through actual on-site installation. This inclined support frame 9 structure is installed on the front of the transformer, which can significantly reduce the risk of transformer tipping over and greatly improve the installation stability of offshore transformers. In addition, both ends of the upper clamp 10 of the present invention are provided with a rocker sealing box 14 with a fixed rocker arm 13 inside. The present invention uses the fixed rocker arm 13 to directly pass through the rocker sealing box 14 and act on the transformer body to prevent it from moving left and right, thereby further improving the vibration stability of the transformer. At the same time, the rocker sealing box 14 ensures the overall sealing of the transformer chamber shell.

[0045] In order to solve the problems of low heat dissipation efficiency of dry-type transformers for offshore wind power due to factors such as large insulation distance and multiple insulating partitions under air-water cooling operation, the present invention has also made further improvements to the heat dissipation structure of the transformer, wherein the present invention symmetrically arranges arc-shaped partitions 7 between the high-voltage coil groups of adjacent phases, so that the cooling air entering from the lower end of the transformer will flow between the partition 7 and the high-voltage coil group on the corresponding side, thereby enhancing the heat dissipation capacity of the coil surface, and at the same time, the lower end gap between the two adjacent layers of the insulating cylinder 3 will be blocked by the thickened portion 301, so that the cooling air can only enter from the lower end between the low-voltage coil 2 and the insulating cylinder 3 and between the insulating cylinder 3 and the high-voltage coil group, thereby improving the heat dissipation efficiency.

Claims

1. A high voltage dry-type transformer for offshore wind power, characterized in that: The invention comprises an inclined support frame (9) and a multi-phase device body clamped and fixed by an upper clamp (10) and a lower clamp (11), wherein the device body comprises an iron core (1) and a low-voltage coil (2), an insulating cylinder (3) and a high-voltage coil group which are sequentially sleeved on the core column of the iron core (1) from the inside to the outside, wherein the high-voltage coil group comprises an upper high-voltage coil (4) and a lower high-voltage coil (5) connected by a coil connecting plate (6), a top bracket (15) is provided on the upper clamp (10), and a supporting foot (8) is provided on the lower side of the lower clamp (11), and the upper end of the inclined support frame (9) is connected to the corresponding top bracket (15), and the lower end is connected to the corresponding supporting foot (8).

2. The high voltage dry-type transformer for offshore wind power according to claim 1 is characterized in that: The coil connection plate (6) is made of silicone, and the lower side of the coil connection plate (6) is bonded to the upper end surface of the lower high-voltage coil (5) by room temperature vulcanized silicone rubber coating, and the lower end surface of the upper high-voltage coil (4) is bonded to the upper side of the coil connection plate (6) by room temperature vulcanized silicone rubber coating.

3. The high voltage dry-type transformer for offshore wind power according to claim 2 is characterized in that: The coil connection plate (6) is provided with a limiting groove (601), and the limiting groove (601) cooperates with a limiting block provided on the lower end surface of the upper high-voltage coil (4).

4. The high voltage dry-type transformer for offshore wind power according to claim 1 is characterized in that: The upper end of the inclined support frame (9) is connected to the corresponding top bracket (15) through a first connecting rod (17), and the lower end of the inclined support frame (9) is connected to the corresponding supporting foot (8) through a second connecting rod (16).

5. The high voltage dry-type transformer for offshore wind power according to claim 4 is characterized in that: The inclined support frame (9) is provided with a first connecting block (901) and a second connecting block (902), and one end of the first connecting rod (17) is fixed to the lower side of the top support (15), and the other end is fixed to the first connecting block (901), and one end of the second connecting rod (16) is fixed to the supporting foot (8), and the other end is fixed to the second connecting block (902).

6. The high voltage dry-type transformer for offshore wind power according to claim 4 is characterized in that: An insulating heat shrinkable sleeve is sleeved on the outer side of the main body of the inclined support frame (9).

7. The high voltage dry-type transformer for offshore wind power according to claim 1 is characterized in that: The lower end of the inclined support frame (9) is provided with a mounting plate (903), and the mounting plate (903) is fixed on the corresponding supporting foot (8), and the upper clamp (10) is provided with a hanging plate (12).

8. The high voltage dry-type transformer for offshore wind power according to claim 1, characterized in that: Both ends of the upper clamp (10) are provided with a rocker sealing box (14) with a fixed rocker arm (13) inside, wherein the outer side of the rocker sealing box (14) is connected to the transformer chamber shell, the head end of the fixed rocker arm (13) extends to the outside of the rocker sealing box (14) and is fixed, and the rear end of the fixed rocker arm (13) is connected to the upper clamp (10).

9. The high voltage dry-type transformer for offshore wind power according to claim 1, characterized in that: Arc-shaped partitions (7) are symmetrically arranged between the high-voltage coil groups of adjacent phases.

10. The high voltage dry-type transformer for offshore wind power according to claim 1, characterized in that: The insulating tube (3) is a multi-layer structure, and the lower end of each single layer of the insulating tube (3) is provided with a thickened portion (301), and the lower end gap between two adjacent layers of the insulating tube (3) is blocked by the thickened portion (301).

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