Transformer DC bushing, installation method and processing method

Abstract

The invention discloses a transformer direct-current bushing, an installation method and a processing method, the transformer direct-current bushing 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 sleeves the outer side of the conductor, the core body is made of epoxy resin impregnated glass fibers, 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 invention, the conductor is used for replacing a lead in an existing bushing, so that the load intensity of the transformer direct-current bushing is enhanced.

Description

Technical Field

[0001] The present invention relates to the technical field of transformers, and in particular to a transformer DC bushing, an installation method and a processing method. Background Art

[0002] High voltage transmission is usually used in the power transmission process. Transformers are needed to convert the high voltage transmitted by the transmission line into various levels of voltage to meet the voltage requirements of various users. This plays a vital role in people's production and life.

[0003] When the transformer is connected to external electrical equipment, a bushing is required to connect the high and low voltage windings inside the transformer to the external leads of the oil tank. As a current-carrying conductor, the bushing passes through a box or wall with an unequal potential, plays an insulating and mechanical support role, and is one of the key devices to ensure the safe and stable operation of the system.

[0004] Since the existing bushings are connected internally with wires, the current that the wires can carry is relatively small, making the existing bushings unable to be used as connection carriers for large current transformers. In addition, the existing bushings include oil-filled bushings for lower voltage levels and oil-paper capacitor bushings for high and ultra-high voltage. However, both oil-filled bushings and oil-paper capacitor bushings have the risk of oil leakage, and bushing failures are prone to occur during system operation, leading to accidents. Summary of the invention

[0005] The embodiments of the present invention provide a transformer DC bushing, an installation method and a processing method, aiming to solve the problem that the current that the wire of the existing bushing can carry is small, so that the existing bushing cannot be used as a connection carrier of a large current transformer.

[0006] In order to solve the above problems, in the first aspect, an embodiment of the present invention provides a transformer DC bushing, wherein both ends of the transformer DC bushing are respectively used to connect the transformer and the electrical equipment, including: a conductor, a core, a porcelain sleeve, a flange and an end cover, wherein one end of the conductor is provided with a first connection part for connecting the transformer, and the other end is provided with a second connection part for connecting the electrical equipment; the core is sleeved on the outside of the conductor, the material of the core is epoxy resin impregnated glass fiber, and a multi-layer capacitor screen is provided on the core; the porcelain sleeve and the flange are sequentially sleeved on the outside of the core, and one end of the porcelain sleeve abuts the second connection part, and one end of the flange abuts the other end of the porcelain sleeve; one end of the end cover abuts one end of the core close to the first connection part, and the other end is connected to one end of the conductor.

[0007] In a second aspect, an embodiment of the present invention further provides a method for installing a DC bushing of a transformer as described above, comprising:

[0008] The core is sheathed on the outside of the conductor;

[0009] The porcelain sleeve and the flange are sequentially sleeved on the outside of the core body, and one end of the porcelain sleeve is abutted against the second connecting portion of the conductor, and one end of the flange is abutted against the other end of the porcelain sleeve;

[0010] One end of the end cap is abutted against one end of the core body close to the first connecting portion of the conductor, and the other end of the end cap is connected to one end of the conductor.

[0011] In a third aspect, an embodiment of the present invention further provides a method for processing the DC bushing of the transformer as described above, comprising:

[0012] The core is wound. The length parameters of each layer of capacitor screen are designed according to the electric field strength requirements of the voltage level. The parameters are selected and the computer winding machine program is set according to the sleeve design parameters. During the sleeve core winding process, the temperature is controlled to continuously degas the epoxy resin chemical reaction and gradually solidify.

[0013] After the core is cured and wound, it is sent to the oven and the reasonable step temperature and duration of the oven are set to ensure that the core is completely cured;

[0014] Demolding the core body: send the core body to the demoulding equipment for fixation, and use hydraulic pressure to slowly push out the mold so that the mold is separated from the core body to complete the demoulding of the core body;

[0015] Core machining: Use tooling to fix the core and perform turning and shaping according to the core design drawings to complete the core machining;

[0016] Assemble the parts, assemble the core body on the conductor, assemble the porcelain sleeve and flange on the core body in turn, put on the end cover, insert the bolts into the conductor with the spring and lock them to the designed distance to complete the assembly.

[0017] The embodiment of the present invention provides a transformer DC bushing, an installation method and a processing method, wherein the transformer DC bushing includes: a conductor, a core, a porcelain sleeve, a flange and an end cover, wherein one end of the conductor is provided with a first connection part for connecting a transformer, and the other end is provided with a second connection part for connecting an electrical device; the core is sleeved on the outside of the conductor, the material of the core is epoxy resin impregnated glass fiber, and a multi-layer capacitor screen is provided on the core; the porcelain sleeve and the flange are sleeved on the outside of the core in sequence, and one end of the porcelain sleeve abuts the second connection part, and one end of the flange abuts the other end of the porcelain sleeve; one end of the end cover abuts on one end of the core close to the first connection part, and the other end is connected to one end of the conductor. The present invention replaces the wire in the existing bushing with a conductor, thereby enhancing the load strength of the bushing, and sleeves the core made of epoxy resin impregnated glass fiber on the outside of the conductor, and is provided with a multi-layer capacitor screen to improve the insulation degree of the bushing, and the whole bushing adopts a solid structure that is relatively stable, which solves the problem that the wire of the existing bushing can carry a small current, so that the existing bushing cannot be used as a connection carrier of a large current transformer. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying any creative work.

[0019] Figure 1 A schematic structural diagram of a DC bushing of a transformer provided in an embodiment of the present invention;

[0020] Figure 2 A partial view provided for an embodiment of the present invention;

[0021] Figure 3 A schematic diagram of the structure of a core provided by an embodiment of the present invention;

[0022] Figure 4 A partial view B provided for an embodiment of the present invention;

[0023] Figure 5 A schematic diagram of a flow chart of a method for installing a DC bushing of a transformer provided in an embodiment of the present invention;

[0024] Figure 6 A schematic flow chart of a method for processing a transformer DC bushing provided in an embodiment of the present invention.

[0025] Description of the symbols in the figure:

[0026] 1. conductor; 11. first connection portion; 12. second connection portion; 121. abutment portion; 13. communication cavity; 14. opening; 15. step portion; 151. sealing groove; 16. flow gap; 17. flow hole;

[0027] 2. Core; 21. Capacitive screen;

[0028] 3. Porcelain sleeve; 31. Insulation cavity;

[0029] 4. Flange; 41. End screen;

[0030] 5. End cover; 51. Spring;

[0031] 6. Sealing ring;

[0032] 7. Pressure equalizing ring;

[0033] 8. Sealing gasket. DETAILED DESCRIPTION

[0034] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0035] It should be understood that when used in this specification and the appended claims, the terms "include" and "comprises" indicate the presence of described features, integers, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or combinations thereof.

[0036] It should also be understood that the terms used in this specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. As used in the specification of the present invention and the appended claims, unless the context clearly indicates otherwise, the singular forms "a", "an" and "the" are intended to include plural forms.

[0037] It should be further understood that the term "and / or" used in the present description and the appended claims refers to any and all possible combinations of one or more of the associated listed items, and includes these combinations.

[0038] Combination Figure 1As shown, an embodiment of the present invention provides a transformer DC bushing, wherein both ends of the transformer DC bushing are respectively used to connect the transformer and the electrical equipment, including: a conductor 1, a core 2, a porcelain sleeve 3, a flange 4 and an end cover 5, wherein one end of the conductor 1 is provided with a first connection portion 11 for connecting the transformer, and the other end is provided with a second connection portion 12 for connecting the electrical equipment; the core 2 is sleeved on the outside of the conductor 1, the material of the core 2 is epoxy resin impregnated glass fiber, and a multilayer capacitor screen 21 is provided on the core 2; the porcelain sleeve 3 and the flange 4 are sleeved on the outside of the core 2 in sequence, and one end of the porcelain sleeve 3 abuts the second connection portion 12, and one end of the flange 4 abuts the other end of the porcelain sleeve 3; one end of the end cover 5 abuts on one end of the core 2 close to the first connection portion 11, and the other end is connected to one end of the conductor 1.

[0039] In the embodiment of the present invention, the conductor 1 replaces the wire in the existing bushing, thereby enhancing the load strength of the transformer DC bushing, and the core 2 made of epoxy resin impregnated glass fiber is set on the outside of the conductor 1, and a multi-layer capacitor screen 21 is provided to improve the insulation degree of the transformer DC bushing, and the entire transformer DC bushing adopts a solid structure that is relatively stable, which solves the problem that the wire of the existing bushing can carry a small current, making the existing bushing unable to be used as a connection carrier of a large current transformer. Among them, the core 2 is used for voltage division, plays an insulating role, and prevents the insulation effect of the transformer DC bushing from being broken down; the multi-layer capacitor screen 21 forms a concentric cylindrical capacitor to make the radial and axial electric fields between the intermediate conductor 1 of the transformer DC bushing and the grounding flange 4 uniformly distributed; the porcelain sleeve 3 plays an external insulation role and protects the internal insulation of the core 2 from being corroded by the external atmosphere; the flange 4 is connected and sealed between the inside and outside of the transformer, and is used to seal the gap between the transformer DC bushing and the transformer.

[0040] Specifically, the conductor 1 is made of aluminum. Compared with copper used in the existing bushing, aluminum has a higher load strength, so that the conductor 1 can carry a larger current.

[0041] Specifically, the distances between adjacent capacitive screens 21 are equal, and the distance between the capacitive screens 21 ranges from 2.9 mm to 4.9 mm.

[0042] In some embodiments, a communication cavity 13 is disposed inside the conductor 1 , and an opening 14 facing the transformer is disposed at one end of the conductor 1 , and the opening 14 is connected to the communication cavity 13 .

[0043] In this embodiment, the temperature of the transformer is relatively high during power transmission, and oil is provided inside the transformer. When the temperature of the transformer increases, the oil inside the transformer expands and causes excessive internal pressure. The connecting cavity 13 provided inside the conductor 1 not only plays a buffering role, but also can synchronize the temperature inside the transformer for easy detection.

[0044] 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 of the conductor 1, 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.

[0045] In this embodiment, since the connecting cavity 13 is smaller than the transformer, the setting of the flow hole 17 and the flow gap 16 enables the oil in the transformer that expands due to heat to flow through the connecting cavity 13, the flow hole 17 and the flow gap 16, further enhancing the buffering effect of the conductor 1 in preventing thermal expansion of the transformer.

[0046] In a specific 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 expands due to heat, the spring 51 stretches, and the connection between the end cap 5 and the conductor 1 becomes 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 step 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 is sleeved on the sealing groove 151 to isolate the oil inside the transformer from flowing to the external insulating part composed of the porcelain sleeve 3 and the flange 4, and can improve the sealing between the conductor 1 and the core 2, thereby enhancing the voltage dividing effect of the core 2, thereby 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 porcelain 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 connected to the electrical equipment, thereby increasing the load strength of the conductor 1 so that more electrical equipment can be connected. One end of the porcelain sleeve 3 abuts against the abutment portion 121 to achieve better insulation effect.

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

[0052] In this embodiment, the inner insulation composed of the core 2 and the multi-layer capacitor screen 21 arranged on the core 2, and the outer insulation composed of the porcelain sleeve 3 and the flange 4, are provided with an insulating medium between the inner insulation and the outer insulation, which can further improve the overall insulation effect of the transformer DC bushing.

[0053] In some embodiments, a terminal screen 41 for detecting the capacitance and dielectric loss of the capacitive screen 21 is disposed on the flange 4 .

[0054] In this embodiment, the end screen 41 is used to detect the capacitance and dielectric loss of the capacitive screen 21, so as to determine the insulation condition of the capacitive screen 21. Specifically, a grounding tube (not shown) is also provided on the flange 4, and the grounding tube is connected to the end screen 41, so that the end screen 41 can accurately detect the capacitance and dielectric loss of the capacitive screen 21.

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

[0056] In this embodiment, the grading ring 7 is used to balance the electric field at the tail of the DC bushing of the transformer, and can also 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 connecting 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 oil in the transformer from flowing into each other.

[0059] The present invention further provides a method for installing the DC bushing of the transformer as described above, comprising steps S10 to S30:

[0060] S10, sleeve the core 2 on the outside of the conductor 1;

[0061] S20, sequentially sleeve the porcelain sleeve 3 and the flange 4 on the outside of the core body 2, and abut one end of the porcelain sleeve 3 against the second connecting portion 12 of the conductor 1, and abut one end of the flange 4 against the other end of the porcelain sleeve 3;

[0062] S30 , abut one end of the end cap 5 against one end of the first connecting portion 11 of the core 2 close to the conductor 1 , and connect the other end of the end cap 5 to one end of the conductor 1 .

[0063] In the embodiment of the present invention, the conductor 1 replaces the wire in the existing bushing, thereby enhancing the load strength of the DC bushing of the transformer, and the core 2 made of epoxy resin impregnated glass fiber is sleeved on the outside of the conductor 1, and a multi-layer capacitor screen 21 is provided to improve the insulation degree of the DC bushing of the transformer, and the porcelain sleeve 3 and the flange 4 are sequentially sleeved on the outside of the core 2, so that the DC bushing of the entire transformer adopts a solid structure that is relatively stable, thereby solving the problem that the wire of the existing bushing can carry a small current, making the existing bushing unable to be used as a connection carrier of a large current transformer.

[0064] The present invention also provides a method for processing the DC bushing of the transformer as described above, comprising steps S100 to S500:

[0065] S100, winding the core body, determining the length parameters of each layer of the capacitor screen 21 designed according to the electric field strength requirements of the voltage level, selecting the parameters, setting the computer winding machine program according to the sleeve design parameters, and in the process of winding the sleeve core body 2, controlling the temperature to continuously perform the chemical reaction of the epoxy resin for degassing, and gradually curing;

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

[0067] S200, core curing. After the core 2 is wound, it is sent into an oven, and reasonable oven step temperatures and durations are set to ensure that the core 2 is completely cured.

[0068] S300, core demoulding, sending the core 2 to the demoulding equipment for fixing, and slowly ejecting the mold by hydraulic pressure, so that the mold is separated from the core 2, so as to complete the demoulding of the core 2;

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

[0070] S400, machining the core body, fixing the core body 2 with a tool, and performing turning machining according to the design drawing of the core body 2 to complete the machining of the core body 2;

[0071] In this step, the rough machining feed amount is not more than 0.5mm, and the fine machining feed amount is not more than 0.1mm.

[0072] S500, assembling parts, assembling the core 2 on the conductor 1, assembling the porcelain sleeve 3 and the flange 4 on the core 2 in sequence, putting the end cover 5 on, inserting the bolts in the conductor 1 with the spring 51 and tightening them to the designed distance, and then completing the assembly.

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

[0074] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0075] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

[0076] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can easily think of various equivalent modifications or replacements within the technical scope disclosed by the present invention, and these modifications or replacements should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be based on the protection scope of the claims.

Claims

1. A transformer DC bushing, wherein the two ends of the transformer DC bushing are respectively used to connect the transformer and the electrical equipment, characterized in that: include: A conductor, wherein one end of the conductor is provided with a first connection portion for connecting to a transformer, and the other end of the conductor is provided with a second connection portion for connecting to an electrical device; A core body, wherein the core body is sleeved on the outside of the conductor, the material of the core body is epoxy resin impregnated glass fiber, and a multi-layer capacitor screen is arranged on the core body; A porcelain sleeve and a flange, wherein the porcelain sleeve and the flange are sequentially sleeved on the outside of the core body, and one end of the porcelain sleeve abuts against the second connecting portion, and one end of the flange abuts against the other end of the porcelain sleeve; An end cap, one end of which abuts against one end of the core body close to 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: A communication cavity is arranged inside the conductor, and an opening facing the transformer is arranged at one end of the conductor, and the opening is connected with the communication cavity.

3. The transformer DC bushing according to claim 2, characterized in that: The conductor is provided with a step portion, a flow gap is provided between the step portion and the first connecting portion, and the conductor is provided with at least one flow hole between the step 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.

4. The transformer DC bushing according to claim 3, characterized in that: Also includes: At least one sealing ring, at least one sealing groove is provided between the step 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 portion extends outwardly to form an abutting portion, and one end of the porcelain sleeve abuts against the abutting portion.

6. The transformer DC bushing according to claim 1, characterized in that: An insulating cavity for filling an insulating medium is arranged between the porcelain sleeve and the core body.

7. The transformer DC bushing according to claim 1, characterized in that: The flange is provided with an end screen for detecting the capacitance and dielectric loss of the capacitive screen.

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

9. A method for installing a transformer DC bushing according to any one of claims 1 to 8, characterized in that: include: The core is sheathed on the outside of the conductor; The porcelain sleeve and the flange are sequentially sleeved on the outside of the core body, and one end of the porcelain sleeve is abutted against the second connecting portion of the conductor, and one end of the flange is abutted against the other end of the porcelain sleeve; One end of the end cap is abutted against one end of the core body close to the first connecting portion of the conductor, and the other end of the end cap is connected to one end of the conductor.

10. A method for processing a transformer DC bushing as claimed in claims 1 to 8, characterized in that: include: The core is wound. The length parameters of each layer of capacitor screen are designed according to the electric field strength requirements of the voltage level. The parameters are selected and the computer winding machine program is set according to the sleeve design parameters. During the sleeve core winding process, the temperature is controlled to continuously degas the epoxy resin chemical reaction and gradually solidify. The core is cured. After the core is wound, it is sent into the oven and the reasonable step temperature and duration of the oven are set to ensure that the core is completely cured; Demolding the core body: send the core body to the demoulding equipment for fixation, and use hydraulic pressure to slowly push out the mold so that the mold is separated from the core body to complete the demoulding of the core body; Core machining: Use tooling to fix the core and perform turning and shaping according to the core design drawings to complete the core machining; Assemble the parts, assemble the core body on the conductor, assemble the porcelain sleeve and flange on the core body in turn, put on the end cover, insert the bolts into the conductor with the spring and lock them to the designed distance to complete the assembly.

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