Transformer direct current bushing

Abstract

The utility model discloses a transformer DC bushing, which comprises a conductor, a core body, a porcelain bushing, a flange and an end cover, one end of the conductor is provided with a first connecting part used for connecting a transformer, and the other end of the conductor is provided with a second connecting part used for connecting electric equipment; the core body is sleeved on the outer side of the conductor, the core body is an epoxy resin impregnated glass fiber core body, and a plurality of layers of capacitive screens are arranged on the core body; the porcelain bushing and the flange sequentially sleeve the outer side of the core body, one end of the porcelain bushing abuts against the second connecting part, and one end of the flange abuts against the other end of the porcelain bushing; one end of the end cover abuts against one end of the core close to the first connecting part, and the other end is connected to one end of the conductor. According to the transformer direct-current bushing, a lead in an existing bushing is replaced by the conductor, the load strength of the transformer direct-current bushing is enhanced, the epoxy resin impregnated glass fiber core body is provided with the multiple layers of capacitive screens, the insulation degree of the transformer direct-current bushing is improved, and the whole transformer direct-current bushing is stable due to the fact that the whole transformer direct-current bushing is of a solid structure.

Description

Technical Field

[0001] This utility model relates to the field of transformer technology, and in particular to a transformer DC bushing. Background Technology

[0002] High-voltage power transmission is typically used in the power transmission process. Transformers are required to convert the high voltage transmitted through the transmission lines into various voltage levels to meet the needs of different users, playing a vital role in people's production and daily life.

[0003] When connecting transformers to external electrical equipment, bushings are required. Bushings connect the high-voltage and low-voltage windings inside the transformer to the external leads of the tank. As current-carrying conductors passing through the tank or wall at different potentials, bushings provide insulation and mechanical support, and are one of the key devices to ensure the safe and stable operation of the system.

[0004] Because existing bushings use internal wire connections, and the current that the wires can carry is relatively small, existing bushings cannot be used as connection carriers for high-current transformers. Moreover, existing bushings include oil-filled bushings for lower voltage levels and oil-paper capacitor bushings for high voltage and ultra-high voltage levels. However, both oil-filled bushings and oil-paper capacitor bushings have the risk of oil leakage, which can easily lead to bushing failures during system operation and cause accidents. Utility Model Content

[0005] This utility model provides a transformer DC bushing, which aims to solve the problem that the current that the conductors of existing bushings can carry is relatively small, making existing bushings unsuitable as connection carriers for high-current transformers.

[0006] To address the aforementioned problems, this utility model provides a transformer DC bushing. The transformer DC bushing has two ends for connecting a transformer and electrical equipment, respectively, and includes: a conductor, a core, a porcelain bushing, a flange, and an end cap. One end of the conductor has a first connection portion for connecting to the transformer, and the other end has a second connection portion for connecting to the electrical equipment. The core is sleeved on the outside of the conductor. The core is made of epoxy resin impregnated glass fiber and has multiple layers of capacitive screens. The porcelain bushing and flange are sequentially sleeved on the outside of the core, with one end of the porcelain bushing abutting against the second connection portion and one end of the flange abutting against the other end of the porcelain bushing. One end of the end cap abuts against the end of the core near the first connection portion, and the other end is connected to one end of the conductor.

[0007] Furthermore, the conductor has a communicating cavity inside, and one end of the conductor has an opening facing the transformer, the opening being connected to the communicating cavity.

[0008] Furthermore, the conductor is provided with a stepped portion, and a flow gap is provided between the stepped portion and the first connecting portion. The conductor is provided with at least one flow hole between the stepped portion and the first connecting portion, one end of the flow hole is connected to the connecting cavity, and the other end is connected to the flow gap.

[0009] Furthermore, it also includes: at least one sealing ring, wherein at least one sealing groove is provided between the stepped portion and the second connecting portion, and the sealing ring is sleeved on the sealing groove.

[0010] Furthermore, the second connecting portion extends outward to form an abutting portion, and one end of the ceramic sleeve abuts against the abutting portion.

[0011] Furthermore, an insulating cavity for filling with an insulating medium is provided between the ceramic sleeve and the core.

[0012] Furthermore, the flange is provided with a end screen for detecting the capacitance and dielectric loss of the capacitor screen.

[0013] Furthermore, the transformer DC bushing also includes an equalizing ring, which is sleeved on the first connecting portion, and the other end of the end cap abuts against the equalizing ring and is connected to one end of the conductor.

[0014] Furthermore, the conductor is an aluminum conductor.

[0015] Furthermore, the other end of the end cap is connected to one end of the conductor by a spring.

[0016] This utility model provides a transformer DC bushing, including: a conductor, a core, a porcelain bushing, a flange, and an end cap. One end of the conductor has a first connection portion for connecting to a transformer, and the other end has a second connection portion for connecting to electrical equipment. The core is sleeved on the outside of the conductor, and the core is made of epoxy resin impregnated glass fiber, with multiple layers of capacitor shielding. The porcelain bushing and flange are sequentially sleeved on the outside of the core, with one end of the porcelain bushing abutting the second connection portion and one end of the flange abutting the other end of the porcelain bushing. One end of the end cap abuts the end of the core near the first connection portion, and the other end is connected to one end of the conductor. This utility model enhances the load strength of the transformer DC bushing by replacing the conductor with the existing wires in the bushing. The epoxy resin impregnated glass fiber core sleeved on the outside of the conductor, along with the multiple layers of capacitor shielding, improves the insulation of the transformer DC bushing. Furthermore, the entire transformer DC bushing uses a solid structure, which is more stable. This solves the problem that the existing bushing's conductors can only carry a small current, making it unsuitable as a connection carrier for high-current transformers. Attached Figure Description

[0017] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of the structure of the transformer DC bushing provided in an embodiment of the present utility model;

[0019] Figure 2 Partial Figure A provided for an embodiment of this utility model;

[0020] Figure 3 A schematic diagram of the core structure provided in an embodiment of this utility model;

[0021] Figure 4 Partial Figure B provided for an embodiment of this utility model;

[0022] Figure 5 A flowchart illustrating the installation method of the transformer DC bushing provided in this embodiment of the utility model;

[0023] Figure 6 A flowchart illustrating the processing method of the transformer DC bushing provided in this embodiment of the utility model.

[0024] Explanation of the markings in the image:

[0025] 1. Conductor; 11. First connecting part; 12. Second connecting part; 121. Abutting part; 13. Communicating cavity; 14. Opening; 15. Stepped part; 151. Sealing groove; 16. Flow gap; 17. Flow hole;

[0026] 2. Core; 21. Capacitive touchscreen;

[0027] 3. Porcelain sleeve; 31. Insulating cavity;

[0028] 4. Flange; 41. End screen;

[0029] 5. End cap; 51. Spring;

[0030] 6. Sealing ring;

[0031] 7. Equalizing ring;

[0032] 8. Sealing gaskets. Detailed Implementation

[0033] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present utility model.

[0034] It should be understood that, when used in this specification and the appended claims, the terms "comprising" and "including" indicate the presence of the described features, integrals, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or collections thereof.

[0035] It should also be understood that the terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the scope of the invention. As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise.

[0036] It should also be further understood that the term "and / or" as used in this specification and the appended claims refers to any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0037] Combination Figure 1-4 As shown, this utility model embodiment provides a transformer DC bushing, with both ends used to connect a transformer and electrical equipment, respectively. It includes: a conductor 1, a core 2, a porcelain bushing 3, a flange 4, and an end cap 5. One end of the conductor 1 is provided with a first connecting portion 11 for connecting to the transformer, and the other end is provided with a second connecting portion 12 for connecting to the electrical equipment. The core 2 is sleeved on the outside of the conductor 1. The core 2 is an epoxy resin impregnated glass fiber core, and a multi-layer capacitor screen 21 is provided on the core 2. The porcelain bushing 3 and the flange 4 are sequentially sleeved on the outside of the core 2, with one end of the porcelain bushing 3 abutting against the second connecting portion 12, and one end of the flange 4 abutting against the other end of the porcelain bushing 3. One end of the end cap 5 abuts against the end of the core 2 near the first connecting portion 11, and the other end is connected to one end of the conductor 1.

[0038] In this embodiment of the invention, the load strength of the transformer DC bushing is enhanced by replacing the existing wires in the bushing with conductor 1. A core 2 made of epoxy resin impregnated glass fiber is fitted over the conductor 1, and a multi-layer capacitor shield 21 is provided to improve the insulation of the transformer DC bushing. Furthermore, the solid structure of the entire transformer DC bushing provides greater stability, solving the problem that the existing bushing's wires can only carry a small current, making it unsuitable as a connection carrier for high-current transformers. Specifically, the core 2 serves as a voltage divider and insulation, preventing the insulation of the transformer DC bushing from being broken down; the multi-layer capacitor shield 21 forms a concentric cylindrical capacitor to ensure uniform radial and axial electric field distribution between the conductor 1 and the grounding flange 4 of the transformer DC bushing; the porcelain sleeve 3 provides external insulation and protects the internal insulation of the core 2 from atmospheric corrosion; and the flange 4 seals the gap between the transformer DC bushing and the transformer itself.

[0039] Specifically, conductor 1 is an aluminum conductor. Compared with the copper material used in existing bushings, aluminum has a higher load strength, which allows conductor 1 to carry a larger current.

[0040] Specifically, the distance between adjacent capacitive screens 21 is equal, and the distance between capacitive screens 21 ranges from 2.9mm to 4.9mm.

[0041] In some embodiments, a connecting cavity 13 is provided inside the conductor 1, and one end of the conductor 1 is provided with an opening 14 facing the transformer, the opening 14 connecting the connecting cavity 13.

[0042] In this embodiment, the transformer has a high temperature during power transmission, and the transformer is equipped with oil. When the transformer temperature increases, the oil inside the transformer expands, which will cause excessive internal pressure. The connecting cavity 13 inside the conductor 1 not only plays a buffering role, but also synchronizes the temperature inside the transformer, which is convenient for detection.

[0043] In some embodiments, a step portion 15 is provided on the conductor 1, a flow gap 16 is provided between the step portion 15 and the first connecting portion 11, and at least one flow hole 17 is provided between the step portion 15 and the first connecting portion 11. One end of the flow hole 17 is connected to the connecting cavity 13, and the other end is connected to the flow gap 16.

[0044] In this embodiment, since the connecting cavity 13 is relatively small compared to the transformer, the arrangement of the flow hole 17 and the flow gap 16 allows the oil inside the transformer that expands due to heat to flow through the connecting cavity 13, the flow hole 17 and the flow gap 16, further improving the buffering effect of the conductor 1 in preventing the transformer from expanding due to heat.

[0045] In a specific embodiment, the other end of the end cap 5 is connected to one end of the conductor 1 by a spring 51.

[0046] In this embodiment, the end cap 5 and the conductor 1 are connected by a spring 51. During the power transmission process of the transformer, the DC bushing of the transformer is heated and expands, the spring 51 extends, and the connection between the end cap 5 and the conductor 1 becomes more stable as the temperature rises.

[0047] In some embodiments, the transformer DC bushing further includes: at least one sealing ring 6, at least one sealing groove 151 is provided between the stepped portion 15 and the second connecting portion 12, and the sealing ring 6 is sleeved on the sealing groove 151.

[0048] In this embodiment, the sealing ring 6, which is fitted onto the sealing groove 151, can isolate the oil inside the transformer from flowing to the external insulation part composed of the porcelain bushing 3 and the flange 4. It can also improve the sealing between the conductor 1 and the core 2, thereby improving the voltage division effect of the core 2 and making the load strength of the transformer DC bushing higher.

[0049] In some embodiments, the second connecting portion 12 extends outward to form an abutting portion 121, and one end of the ceramic sleeve 3 abuts against the abutting portion 121.

[0050] In this embodiment, the abutment portion 121 increases the diameter of the end of the conductor 1 that connects to the electrical equipment, thereby increasing the load strength of the conductor 1 and enabling the connection of more electrical equipment. The abutment portion 121 at one end of the porcelain sleeve 3 provides a better insulation effect.

[0051] In some embodiments, an insulating cavity 31 for filling with an insulating medium is provided between the ceramic sleeve 3 and the core 2.

[0052] In this embodiment, the inner insulation consisting of the core 2 and the multilayer capacitor screen 21 disposed on the core 2, and the outer insulation consisting of the porcelain bushing 3 and the flange 4, and the addition of an insulating medium between the inner insulation and the outer insulation, can further improve the overall insulation effect of the transformer DC bushing.

[0053] In some embodiments, the flange 4 is provided with a end screen 41 for detecting the capacitance and dielectric loss of the capacitor screen 21.

[0054] In this embodiment, the end screen 41 is used to detect the capacitance and dielectric loss on its capacitor screen 21, thereby determining the insulation condition of the capacitor screen 21. Specifically, a grounding pipe (not shown) is also provided on the flange 4, which is connected to the end screen 41, enabling the end screen 41 to accurately detect the capacitance and dielectric loss of the capacitor screen 21.

[0055] In some embodiments, the transformer DC bushing further includes: an equalizing ring 7, which is sleeved on the first connecting portion 11, and the other end of the end cap 5 abuts against the equalizing ring 7 and is connected to one end of the conductor 1.

[0056] In this embodiment, the equalizing ring 7 is used to equalize the electric field at the tail of the transformer DC bushing and also to seal the connection between the end cover 5 and the conductor 1.

[0057] In some embodiments, the transformer DC bushing further includes a sealing gasket 8, which is disposed between the core 2 and the second connection portion 12.

[0058] In this embodiment, the sealing gasket 8 is used to seal the gap between the core 2 and the conductor 1 to prevent the insulating medium and the transformer oil from flowing into each other.

[0059] Combination Figure 5 As shown, this utility model also provides an installation method for a transformer DC bushing as described above, including steps S10 to S30:

[0060] S10. Place the core 2 on the outside of the conductor 1;

[0061] S20. The porcelain sleeve 3 and the flange 4 are sequentially fitted onto the outside of the core 2, and one end of the porcelain sleeve 3 is connected to the second connection part 12 of the conductor 1, and one end of the flange 4 is connected to the other end of the porcelain sleeve 3.

[0062] S30. One end of the end cap 5 is placed against one end of the core 2 near the first connecting part 11 of the conductor 1, and the other end of the end cap 5 is connected to one end of the conductor 1.

[0063] In this embodiment of the invention, the load strength of the transformer DC bushing is enhanced by replacing the wires in the existing bushing with conductor 1. A core 2 made of epoxy resin impregnated glass fiber is fitted on the outside of conductor 1, and a multi-layer capacitor screen 21 is provided to improve the insulation of the transformer DC bushing. Furthermore, porcelain sleeve 3 and flange 4 are sequentially fitted on the outside of core 2, making the entire transformer DC bushing adopt a solid structure, which is more stable. This solves the problem that the existing bushing's wires can only carry a small current, making it unsuitable as a connection carrier for high-current transformers.

[0064] Combination Figure 6 As shown, this utility model also provides a processing method for a transformer DC bushing as described above, including steps S100 to S500:

[0065] S100, core winding, the length parameters of each layer of capacitor screen 21 are determined according to the voltage level and the electric field strength requirements. The parameters are selected, and the computer winding machine program is set according to the sleeve design parameters. During the winding of the sleeve core 2, the temperature is controlled to continuously degas the epoxy resin chemical reaction and gradually cure it.

[0066] In this step, the winding temperature of core 2 is 90-110℃, which promotes the initial curing process of core 2.

[0067] S200, Core curing: After the core 2 is wound, it is sent into the oven and a reasonable oven temperature and duration are set to ensure that the core 2 is completely cured.

[0068] S300, Core demolding: The core 2 is sent into the demolding equipment and fixed. The mold is slowly ejected by hydraulic pressure, so that the mold is separated from the core 2, thus completing the demolding of the core 2.

[0069] In this step, the mold moving speed is 50mm / minute, which helps to improve the efficiency and success rate of core 2 demolding.

[0070] S400, Core machining: The core 2 is fixed with tooling and turned according to the design drawings of the core 2 to complete the machining of the core 2;

[0071] In this step, the roughing feed rate should not exceed 0.5mm, and the finishing feed rate should not exceed 0.1mm.

[0072] S500, component assembly: Assemble the core 2 onto the conductor 1, then assemble the porcelain sleeve 3 and flange 4 onto the core 2 in sequence, place the end cap 5 on top, and use the spring 51 to insert the bolts into the conductor 1 and tighten them to the designed distance to complete the assembly.

[0073] In this embodiment of the invention, epoxy resin impregnated glass fiber is wound at a high temperature of 90℃-110℃, which promotes the chemical degassing and preliminary curing process of the core 2; the multilayer capacitor screen 21 realizes the reasonable distribution of the electric field strength of the transformer DC bushing, and the equal spacing design method reduces the difficulty of the winding process of the bushing core 2; the transformer DC bushing is locked by spring 51. During the power transmission process of the transformer, the transformer DC bushing is heated and expands, the spring 51 extends, and the connection between the end cover 5 and the conductor 1 becomes more stable as the temperature rises.

[0074] In the above embodiments, the descriptions of each embodiment have different focuses. For parts that are not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0075] Obviously, those skilled in the art can make various modifications and variations to this utility model without departing from its spirit and scope. Since these modifications and variations fall within the scope of the claims of this utility model and their equivalents, this utility model also intends to include these modifications and variations.

[0076] The above description is merely a specific embodiment of this utility model, but the protection scope of this utility model is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in this utility model, and these modifications or substitutions should all be covered within the protection scope of this utility model. Therefore, the protection scope of this utility model should be determined by the scope of the claims.

Claims

1. A transformer DC bushing, wherein both ends of the transformer DC bushing are respectively used to connect a transformer and an electrical device, characterized in that, include: A conductor, one end of which is provided with a first connection part for connecting to a transformer, and the other end of which is provided with a second connection part for connecting to electrical equipment; The core is sleeved on the outside of the conductor. The core is an epoxy resin impregnated glass fiber core, and a multi-layer capacitive screen is provided on the core. A porcelain sleeve and a flange are sequentially fitted onto the outside of the core body, with one end of the porcelain sleeve abutting against the second connecting part and one end of the flange abutting against the other end of the porcelain sleeve. An end cap, one end of which abuts against one end of the core near the first connecting portion, and the other end of which is connected to one end of the conductor.

2. The transformer DC bushing according to claim 1, characterized in that, The conductor has a communicating cavity inside, and one end of the conductor has an opening facing the transformer, which communicates with the communicating cavity.

3. The transformer DC bushing according to claim 2, characterized in that, The conductor has a stepped portion, and a flow gap is provided between the stepped portion and the first connecting portion. The conductor has at least one flow hole between the stepped portion and the first connecting portion, with one end of the flow hole connected to the connecting cavity and the other end connected to the flow gap.

4. The transformer DC bushing according to claim 3, characterized in that, Also includes: At least one sealing ring is provided, and at least one sealing groove is provided between the stepped portion and the second connecting portion, and the sealing ring is sleeved on the sealing groove.

5. The transformer DC bushing according to claim 1, characterized in that, The second connecting part extends outward to form an abutting part, and one end of the ceramic sleeve abuts against the abutting part.

6. The transformer DC bushing according to claim 1, characterized in that, An insulating cavity for filling with an insulating medium is provided between the ceramic sleeve and the core.

7. The transformer DC bushing according to claim 1, characterized in that, The flange is equipped with a final screen for detecting the capacitance and dielectric loss of the capacitor screen.

8. The transformer DC bushing according to claim 1, characterized in that, Also includes: An equalizing ring is sleeved on the first connecting part, and the other end of the end cap abuts against the equalizing ring and is connected to one end of the conductor.

9. The transformer DC bushing according to claim 1, characterized in that, The conductor is an aluminum conductor.

10. The transformer DC bushing according to claim 1, characterized in that, The other end of the end cap is connected to one end of the conductor by a spring.

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