Transformer bushing tap grounding structure

Abstract

The invention discloses a transformer bushing tap grounding structure comprising a base, the base comprises a base body and a butt joint end, and the base is internally provided with an assembling cavity; the end screen leading-out metal terminal is arranged in the assembling concave cavity of the base, one end side of the end screen leading-out metal terminal is provided with an assembling end, and the assembling end extends out of the base; the contact piece is connected to the assembly end; the outer sheath is of a hollow containing structure with one end provided with an opening, the contact piece and the assembling end are contained in a containing cavity of the outer sheath, the outer sheath is fixedly connected to the butt joint end in a sleeving mode, the two opposite ends of the contact piece make contact with the inner wall of the outer sheath respectively, and the contact piece and the assembling end are arranged in the containing cavity of the outer sheath. The end screen leading-out metal terminal, the contact piece, the outer sheath and the butt joint end form a first end screen grounding structure. According to the transformer bushing tap grounding structure, a tap double-grounding structure can be realized, and whether bushing tap grounding is reliable or not can be tested and judged; the structure is simple and reasonable, and maintenance and cost control are easy.

Description

Technical Field

[0001] This invention relates to the field of transformer high-voltage bushing technology, and in particular to a transformer bushing end-screen grounding structure. Background Technology

[0002] 110kV and above transformer bushings mostly adopt distributed capacitor bushings, with the end screen being the outermost capacitor screen of the bushing's capacitor structure. During operation, the end screen of the bushing needs to be grounded to prevent floating points from discharging to ground. In operation, unreliable grounding of the transformer bushing's end screen is a major cause of breakdown and insulation damage to the internal capacitor screen of the transformer bushing.

[0003] Currently, most transformer bushing end screen grounding is single-point grounding. After the sheath is screwed on, the end screen contacts the sheath and is connected to the transformer shell for grounding through the sheath. This makes it impossible to determine whether the internal end screen grounding is in good contact.

[0004] In addition, the existing transformer bushing end-screen grounding structure is complex and has high maintenance and repair costs. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a transformer bushing end screen grounding structure that can realize a double grounding structure of the end screen and can test and judge whether the grounding of the bushing end screen is reliable; the structure is simple and reasonable, easy to repair, maintain and control costs.

[0006] To address the aforementioned technical problems, this invention provides a transformer bushing end-screen grounding structure, comprising: a base, the base including: a base body and a mating end protruding from the base body, the base having an internal assembly cavity; an end-screen lead-out metal terminal, the end-screen lead-out terminal being installed in the assembly cavity of the base, one end of which has an assembly end extending to the outside of the base; a contact piece connected to the assembly end; an outer sheath, the outer sheath being a hollow accommodating structure with an opening at one end, the contact piece and the assembly end being accommodated in the accommodating cavity of the outer sheath, wherein: the outer sheath is securely fitted onto the mating end, the opposite ends of the contact piece are in contact with the inner wall of the outer sheath, the end-screen lead-out metal terminal, the contact piece, the outer sheath and the mating end forming a first end-screen grounding structure; further comprising: a grounding wire connected between the assembly end and the mating end, the grounding wire being detachable from the assembly end, wherein: the outer sheath is detached from the mating end, the end-screen lead-out metal terminal, the grounding wire and the mating end forming a second end-screen grounding structure.

[0007] The outer sheath has internal and external threads for fitting and holding on the inner wall of the opening end and the outer wall of the mating end, respectively, and the outer sheath can be detachably fitted onto the mating end; a first sealing gasket for sealing air is installed between the opening end of the outer sheath and the base body.

[0008] It also includes: an elastic element installed in the accommodating cavity of the outer sheath, with the opposite ends of the elastic element abutting between the inner wall of the outer sheath and the contact piece, and the contact piece, the elastic element, the outer sheath and the mating end forming a ground.

[0009] The assembly end is provided with a through hole for connecting the grounding wire, and also includes a clamping screw for clamping the grounding wire and the assembly end, the clamping screw being detachably connected to the assembly end.

[0010] It also includes: an insulating cylinder, which is installed in the assembly cavity to fix and support the metal terminals of the end screen, and the insulating cylinder isolates the metal terminals of the end screen from the base.

[0011] The insulating cylinder has a convex cross-section and is fitted onto the outside of the metal terminal leading out of the end screen. A second sealing gasket for sealing the insulating oil is installed between the outer wall of the insulating cylinder and the inner wall of the base body.

[0012] A third sealing gasket for sealing the insulating oil is installed between the inner wall of the insulating cylinder and the outer wall of the metal terminal leading out from the end screen.

[0013] A fourth sealing gasket for sealing the insulating oil is installed between the outer wall of the insulating cylinder and the bottom opening of the base body.

[0014] The base is made of stainless steel.

[0015] Specifically, the grounding status of the transformer bushing's final screen grounding structure is tested by changing the connection status of the first set of final screen grounding structures and / or the second set of final screen grounding structures.

[0016] The transformer bushing end-screen grounding structure of the present invention has the following beneficial effects: The transformer bushing end-screen grounding structure includes: a base, the base including: a base body and a mating end protruding from the base body, the base having an assembly cavity inside; an end-screen lead-out metal terminal, the end-screen lead-out terminal being installed in the assembly cavity of the base, one end having an assembly end, the assembly end extending to the outside of the base; a contact piece connected to the assembly end; an outer sheath, the outer sheath being a hollow accommodating structure with an opening at one end, the contact piece and the assembly end being accommodated in the accommodating cavity of the outer sheath, wherein: the outer sheath fastening sleeve Connected to the mating end, the two opposite ends of the contact piece contact the inner wall of the outer sheath respectively. The metal terminal, contact piece, outer sheath, and mating end of the end screen form the first set of end screen grounding structure. It also includes: grounding wires connected between the assembly end and the mating end respectively. The grounding wires are detachable from the assembly end. The outer sheath is detached from the mating end. The metal terminal, grounding wire, and mating end of the end screen form the second set of end screen grounding structure. It can realize the end screen double grounding structure and can test and judge whether the bushing end screen grounding is reliable. The structure is simple and reasonable, easy to repair, maintain and control costs. Attached Figure Description

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

[0018] Figure 1 This is a cross-sectional schematic diagram of the transformer bushing end screen grounding structure according to an embodiment of the present invention. Detailed Implementation

[0019] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] like Figure 1 The image shows an embodiment of the transformer bushing end screen grounding structure of the present invention.

[0021] The transformer bushing end screen grounding structure in this embodiment includes: a base 1, which includes a base body 11 and a mating end 12 protruding from the base body 11. The base 1 has an assembly cavity 13 inside; and an end screen lead-out metal terminal 2, which is installed in the assembly cavity 13 of the base 1. One end of the terminal 2 has an assembly end 20, which extends to the outside of the base 1.

[0022] The contact piece 3 is connected to the assembly end 20; the outer sheath 4 is a hollow accommodating structure with an opening at one end, and the contact piece 3 and the assembly end 20 are accommodated in the accommodating cavity 49 of the outer sheath 4.

[0023] Wherein: the outer sheath 4 is fastened to the mating end 12, the two opposite ends of the contact piece 3 are in contact with the inner wall of the outer sheath 4 respectively, and the metal terminal 2, contact piece 3, outer sheath 4 and mating end 12 of the end screen form the first set of end screen grounding structure.

[0024] It also includes: a grounding wire 5 connected between the assembly end 20 and the docking end 12 respectively. The grounding wire 5 and the assembly end 20 are detachable. The outer sheath 4 is detached from the docking end 12. The metal terminal 2 of the end screen, the grounding wire 5 and the docking end 12 form a second set of end screen grounding structure.

[0025] In practical implementation, the overall cross-section of the base 1 is convex, and its function is to connect the transformer bushing end screen to the bushing body. The base 1 is made of stainless steel and has a certain degree of rust resistance. The base 1 includes: a base body 11 and a mating end 12. The base 1 has an assembly cavity 13 inside, and its mating end 12 has a through hole for the metal terminal 2 of the end screen to pass through.

[0026] One end of the metal terminal 2 leading out from the end screen is the assembly end 20. The assembly end 20 extends to the outside of the base 1 and has a through hole 21 for connecting the grounding wire 5.

[0027] Furthermore, it also includes: an insulating cylinder 6, which is installed in the assembly cavity 13 to fix and support the metal terminal 2 leading out from the end screen.

[0028] The function of the insulating cylinder 6 is to isolate the metal terminal 2 leading out of the end screen from the base 1. In practice, the overall cross-section of the insulating cylinder 6 is convex, and the insulating cylinder 6 is sleeved on the outside of the metal terminal 2 leading out of the end screen.

[0029] Preferably, a second sealing gasket B for sealing insulating oil is installed between the outer wall of the insulating cylinder 6 and the inner wall of the base body 12. A fourth sealing gasket C for sealing insulating oil is installed between the outer wall of the insulating cylinder 6 and the bottom opening of the base body 12.

[0030] Preferably, a third sealing gasket D for sealing the insulating oil is installed between the inner wall of the insulating cylinder 6 and the outer wall of the end screen lead-out metal terminal 2.

[0031] During implementation, the above three sealing gaskets are installed to achieve dual grounding. This means that during bushing testing, both grounding points can be removed to perform bushing dielectric loss, capacitance, and insulation tests. At the same time, grounding condition tests and other tests can also be conducted.

[0032] Furthermore, in this embodiment, the assembly end 20 is equipped with a contact piece 3, and the outer sheath 4 is tightly fitted onto the docking end 12. When the outer sheath 4 and the docking end 12 are tightly connected, the two opposite ends of the contact piece 3 can respectively contact the inner wall of the outer sheath 4. The end screen leads out the metal terminal 2, the contact piece 3, the outer sheath 4 and the docking end 12 to form the first set of end screen grounding structure.

[0033] In this embodiment, the outer sheath 4 is securely fitted onto the mating end 12, achieving a sealing, moisture-proof, and protective effect. The inner wall of the open end of the outer sheath 4 and the outer wall of the mating end 12 are respectively provided with internal and external threads for fitting and retaining, thus enabling the outer sheath 4 to be detachably fitted onto the mating end 12.

[0034] Furthermore, it also includes an elastic element 7 installed in the receiving cavity 49 of the outer sheath 4, with its opposite ends abutting against the inner wall of the outer sheath 4 and the contact piece 3, respectively. This ensures that the contact piece 3, the elastic element 7, and the outer sheath 4 are grounded to the mating end 12 (base 1). In this embodiment, the elastic element 7 is a compression spring, which provides contact surface clamping force to the contact piece 3 and the end-screen lead-out metal terminal 2, ensuring reliable contact between the two.

[0035] Preferably, a first sealing gasket A is installed between the open end of the outer sheath 4 and the base body 11. The function of the first sealing gasket A is to seal the mounting cavity 13 of the base 1 and prevent air from entering or leaving.

[0036] Furthermore, the transformer bushing end screen grounding structure in this embodiment also includes a grounding wire 5 connected between the assembly end 20 and the mating end 12. In this embodiment, the grounding wire 5 is detachable from the assembly end 20, and is specifically implemented according to the following structure. Because the mounting end 20 of the metal terminal 2 leading out of the end screen has a through hole 21, the other end of the grounding wire 5, which is connected to the end side of the base body 11, can pass through the through hole 21. A clamping screw can be used to tighten the wire. The grounding wire 5 is pressed into the through hole 21, and a clamping screw is provided to achieve a detachable connection between the grounding wire 5 and the assembly end 20.

[0037] During implementation, when the outer sheath 4 is separated from the docking end 12, the metal terminal 2 of the end screen, the grounding wire 5 and the docking end 12 can form a second set of end screen grounding structure.

[0038] In this embodiment, the grounding status of the transformer bushing end screen grounding structure can be tested by changing the connection state of the first and / or second end screen grounding structures, as detailed below: After the bushing test, the second set of final screen grounding structure is formed by restoring the final screen lead-out metal terminal 2, grounding wire 5, and mating end 12. This is done by passing the grounding wire 5 through the through hole 21 on the assembly end 20 of the final screen lead-out metal terminal 2 and then tightening the clamping screw. At this point, the transformer bushing final screen grounding structure is grounded. The insulation resistance to ground at the end of the final screen lead-out metal terminal 2 can be tested using a meter to verify the effectiveness of the final screen grounding. If the insulation resistance is 0, it indicates good final screen grounding. Then, the outer sheath 4 is reassembled to implement the first set of final screen grounding structure formed by the final screen lead-out metal terminal 2, contact piece 3, outer sheath 4, and mating end 12, thus achieving double grounding. This effectively ensures good final screen grounding and prevents bushing failure and transformer shutdown due to poor final screen grounding.

[0039] The transformer bushing end screen grounding structure in this embodiment has the following beneficial effects: The transformer bushing end screen grounding structure includes: a base, the base including: a base body and a mating end protruding from the base body, the base having an assembly cavity inside; an end screen lead-out metal terminal, the end screen lead-out terminal being installed in the assembly cavity of the base, one end having an assembly end, the assembly end extending to the outside of the base; a contact piece connected to the assembly end; an outer sheath, the outer sheath being a hollow accommodating structure with an opening at one end, the contact piece and the assembly end being accommodated in the accommodating cavity of the outer sheath, wherein: the outer sheath is securely sleeved... At the mating end, the two opposite ends of the contact piece contact the inner wall of the outer sheath respectively. The metal terminal, contact piece, outer sheath, and mating end of the end screen form the first set of end screen grounding structure. It also includes: grounding wires connected between the assembly end and the mating end respectively. The grounding wires are detachable from the assembly end. The outer sheath is detached from the mating end. The metal terminal, grounding wire, and mating end of the end screen form the second set of end screen grounding structure. It can realize the end screen double grounding structure and can test and judge whether the bushing end screen grounding is reliable. The structure is simple and reasonable, easy to repair, maintain and control costs.

Claims

1. A transformer bushing end-screen grounding structure, characterized in that, include: The base includes: a base body and a mating end protruding from the base body, and the base has an assembly cavity inside; The end screen leads out a metal terminal, which is installed in the mounting cavity of the base, and has a mounting end on one end, which extends to the outside of the base. The contact piece connected to the assembly end; An outer sheath, wherein the outer sheath is a hollow accommodating structure with an opening at one end, and the contact piece and the assembly end are accommodated in the accommodating cavity of the outer sheath, wherein: The outer sheath is fastened to the mating end, and the opposite ends of the contact piece are respectively in contact with the inner wall of the outer sheath. The metal terminal of the end screen, the contact piece, the outer sheath and the mating end form the first set of end screen grounding structure. It also includes: a grounding wire connected between the assembly end and the docking end respectively, wherein the grounding wire and the assembly end are detachable, wherein: the outer sheath is detached from the docking end, and the metal terminal of the end screen, the grounding wire and the docking end form a second end screen grounding structure.

2. The transformer bushing end-screen grounding structure as described in claim 1, characterized in that, The inner wall of the opening end of the outer sheath and the outer wall of the mating end are respectively provided with internal and external threads for fitting and holding, and the outer sheath is detachably fitted onto the mating end. A first sealing gasket for sealing air is installed between the open end of the outer sheath and the base body.

3. The transformer bushing end-screen grounding structure as described in claim 1, characterized in that, Also includes: An elastic element is installed in the accommodating cavity of the outer sheath, with its opposite ends abutting between the inner wall of the outer sheath and the contact piece, respectively. The contact piece, the elastic element, the outer sheath, and the mating end form a ground connection.

4. The transformer bushing end-screen grounding structure as described in claim 1, characterized in that, The assembly end is provided with a through hole for connecting the grounding wire, and also includes a clamping screw for clamping the grounding wire and the assembly end, wherein the clamping screw is detachably connected to the assembly end.

5. The transformer bushing end-screen grounding structure as described in claim 1, characterized in that, Also includes: An insulating cylinder is installed in the assembly cavity to fix and support the metal terminals leading out of the end screen, and the insulating cylinder isolates the metal terminals leading out of the end screen from the base.

6. The transformer bushing end-screen grounding structure as described in claim 5, characterized in that, The insulating cylinder has a convex cross-section and is fitted onto the outside of the metal terminal leading out of the end screen. A second sealing gasket for sealing the insulating oil is installed between the outer wall of the insulating cylinder and the inner wall of the base body.

7. The transformer bushing end-screen grounding structure as described in claim 6, characterized in that, A third sealing gasket for sealing the insulating oil is installed between the inner wall of the insulating cylinder and the outer wall of the metal terminal leading out from the end screen.

8. The transformer bushing end-screen grounding structure as described in claim 6, characterized in that, A fourth sealing gasket for sealing the insulating oil is installed between the outer wall of the insulating cylinder and the bottom opening of the base body.

9. The transformer bushing end-screen grounding structure as described in claim 1, characterized in that, The base is made of stainless steel.

10. The transformer bushing end-screen grounding structure as described in claim 1, characterized in that, The grounding status of the transformer bushing end screen grounding structure is tested by changing the connection status of the first set of end screen grounding structure and / or the second set of end screen grounding structure.

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