Single-phase voltage transformer with fuse grounding

Abstract

The utility model belongs to the high pressure measurement technical field of electric power system, concretely is a kind of single-phase voltage transformer with fuse grounding. Including insulator and the voltage body enclosed in insulator, insulator is installed on bottom plate, the upper portion of insulator is equipped with fuse cavity, spring and high voltage fuse are sequentially arranged in fuse cavity;The inner wall of fuse cavity is equipped with primary high voltage shielding net and fuse screw shield net from inside to outside interval, fuse screw shield net is connected with the primary high voltage end of voltage body, and the opening end of fuse cavity is plugged by insulating plug;The rear end upper portion rear side of insulator is equipped with primary high voltage insulating column, and primary conducting rod is arranged in primary high voltage insulating column and abuts against spring in fuse cavity;The bottom of insulator is equipped with secondary wiring platform. The utility model has simple structure, and it is convenient to operate, and electric field is uniform, and partial discharge is small, and product operation is safe and reliable, and it is applicable to complex environment various voltage grade switch cabinet.

Description

Technical Field

[0001] This utility model belongs to the field of high voltage measurement technology in power systems, specifically a single-phase voltage transformer with a fuse grounding type. Background Technology

[0002] Voltage transformers are devices used in power systems or electrical control systems to measure voltage and electrical energy. In recent years, metal-enclosed switchgear (C-GIS gas-insulated switchgear) with SF6 as the insulating medium has been widely adopted due to its advantages such as small size, high operational safety, and suitability for various high-altitude environments. The voltage transformers used in conjunction with these transformers are dry-type insulated voltage transformers with fuses, developed and designed in recent years. According to design requirements, the high-voltage fuse is electrically connected to the primary terminal of the transformer. This approach has drawbacks such as slightly larger size, more replacement parts, and the potential for large partial discharge when installed together with the transformer in the switchgear. Therefore, switchgear manufacturers and the market have a particular need for a voltage transformer that can directly connect to a fuse and has low partial discharge. Summary of the Invention

[0003] To address the aforementioned problems, the purpose of this utility model is to provide a single-phase voltage transformer with a fuse grounding type, in order to solve the problems of large size, numerous components, and large partial discharge in existing voltage transformers with fuses used in gas-insulated switchgear.

[0004] To achieve the above objectives, the present invention adopts the following technical solution:

[0005] This utility model provides a single-phase voltage transformer with a fuse and grounding, comprising an insulator and a transformer body enclosed within the insulator. The insulator is mounted on a base plate. A fuse cavity with an open end is located horizontally on the upper part of the insulator. A spring and a high-voltage fuse are sequentially arranged within the fuse cavity. The inner wall of the fuse cavity is provided with a primary high-voltage shielding mesh and a fuse sleeve shielding mesh from the inside out, with a gap between the primary high-voltage shielding mesh and the fuse sleeve shielding mesh. The fuse sleeve shielding mesh is connected to the primary high-voltage end of the transformer body. The open end of the fuse cavity is sealed by an insulating plug. A primary high-voltage insulating column is located on the upper rear side of the rear end of the insulator, and a primary conductive rod is located within the primary high-voltage insulating column, abutting against the spring inside the fuse cavity. A secondary terminal block is located at the bottom of the insulator.

[0006] The primary high-voltage shielding mesh includes a primary fuse shielding mesh and a primary conductive rod end cap welded to the rear end of the primary fuse shielding mesh. The primary conductive rod end cap is threadedly connected to the primary conductive rod, and the threaded connection is welded.

[0007] The fuse sleeve shielding mesh includes a blind high-voltage shielding mesh, a fuse sleeve, and a sleeve shielding mesh connected in sequence by spot welding. The fuse sleeve is threadedly connected to the sleeve bolt, and the sleeve bolt is connected to the high-voltage fuse by a spring. The insulating blind is located inside the blind high-voltage shielding mesh and is fastened and sealed to the insulator by bolts.

[0008] The outer surfaces of the primary high-voltage shielding mesh and the fuse screw sleeve shielding mesh are uniformly sandblasted and then sprayed with a layer of semi-conductive paint.

[0009] The outer surface of the insulator is uniformly coated with a metal coating, and a fluorocarbon paint protective layer is sprayed on the outside of the metal coating.

[0010] The upper rear end of the insulator is provided with a primary high voltage equalization ring, which is in contact with the metal coating on the outer surface of the insulator, and the primary conductive rod is located in the middle of the primary high voltage equalization ring;

[0011] The base of the primary high-voltage insulating column is provided with a mounting plate, which is connected to the primary high-voltage equalizing ring by bolts. An insulating plug is provided on the outside of the primary high-voltage insulating column, and the insulating plug is in close contact with the primary high-voltage insulating column by primary bolts.

[0012] The primary high-voltage equalizing ring includes a circular ring and multiple mounting inserts welded onto the circular ring; a layer of semi-conductive crepe paper is half-stacked on the outer side of the circular ring, the outer surface of the mounting inserts is sprayed with semi-conductive paint, and the end face of the mounting inserts is in contact with the metal coating on the outer surface of the insulator.

[0013] The insulator is provided with a lifting ring at its front end and top end. The lifting ring is connected to a nut embedded in the insulator. The end face of the nut is in contact with the metal coating on the outer surface of the insulator.

[0014] The secondary wiring dock is located in a groove at the bottom of the insulator, and the secondary wiring dock is led out through a secondary cable;

[0015] Alternatively, a square exposed secondary platform can be provided at the bottom front end of the insulator, and the secondary terminal block can be connected to the square exposed secondary platform through a secondary cable.

[0016] The insulator is made of epoxy resin casting, and the voltage transformer body, primary high voltage shielding mesh and fuse screw sleeve shielding mesh are integrally formed with the epoxy resin casting.

[0017] The upper ends of the left and right sides of the insulator are narrowed and the lower ends are wide. The fuse cavity is located on the upper part of the insulator and is cylindrical in shape. The front end of the fuse cavity is a cantilever structure. The primary high-voltage insulating column is located vertically upward or horizontally backward on the rear side of the fuse cavity.

[0018] This utility model has the following advantages and beneficial effects:

[0019] This invention utilizes a high- and low-voltage shielding structure composed of a high-voltage shielding ring, a shielding mesh, and a metal coating to enclose the high-voltage fuse's insulating seal within the product. This solves the problem of high partial discharge in existing voltage transformer products with fuses. It is suitable for switchgear of various voltage levels in complex environments. Its main advantages include:

[0020] Simple structure and easy operation: The primary high-voltage terminal of this utility model adopts a primary high-voltage shielding mesh, a fuse screw sleeve shielding mesh and a primary high-voltage equalizing ring, which are cast in one piece. The high-voltage fuse is sealed inside the product. The overall structure is simple and easy to operate.

[0021] With fuse protection and safe to touch while energized: The high-voltage fuse sealed inside the product effectively ensures that it will not burn out in the event of a system failure. The epoxy resin outer layer has a metal coating for low-voltage grounding shielding. The high voltage is sealed and isolated by an insulated plug and an insulated plug. The product surface can be touched while energized, ensuring personal safety during operation.

[0022] Uniform electric field and low partial discharge: The primary high-voltage fuse is placed inside the fuse cavity. The primary high-voltage shielding mesh, the fuse screw sleeve shielding mesh, and the primary high-voltage equalizing ring completely shield the high and low voltage electric fields. The electric field inside and outside the product is uniform, the partial discharge is low, and the product is safe and reliable in operation. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the structure of a single-phase voltage transformer with a fuse grounding according to the present invention; Figure 2 This is a front view of a single-phase voltage transformer with a fuse grounding according to this utility model;

[0024] Figure 3 for Figure 2 The right view;

[0025] Figure 4 for Figure 2 Top view;

[0026] Figure 5 This is a schematic diagram of the structure of the fuse sleeve shielding mesh in this utility model;

[0027] Figure 6 This is a schematic diagram of the structure of the primary high-voltage shielding mesh in this utility model;

[0028] Figure 7 for Figure 6 Side view.

[0029] In the diagram: 1. Voltage transformer body; 2. Primary high-voltage shielding mesh; 3. Fuse sleeve shielding mesh; 4. Primary high-voltage insulating column; 5. Primary high-voltage equalizing ring; 6. Fuse cavity; 7. High-voltage fuse; 8. Secondary terminal block; 9. Base plate; 10. Insulator; 11. Secondary cable; 12. Lifting ring; 13. Mounting plate; 14. Exposed secondary platform; 15. Embedded nut; 16. Closed-end high-voltage shielding mesh; 17. Fuse sleeve; 18. Sleeve shielding mesh; 19. Primary fuse shielding mesh; 20. Primary conductive rod end cap; 21. Primary conductive rod; 22. Insulating plug; 23. Insulating closed end; 24. Sleeve bolt; 25. Primary bolt. Detailed Implementation

[0030] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0031] See Figures 1 to 7 As shown, this utility model provides a single-phase voltage transformer with a fuse grounding type, including an insulator 10 and a transformer body 1 enclosed within the insulator 10. The insulator 10 is mounted on a base plate 9. The upper part of the insulator 10 has a fuse cavity 6 with an open end in the horizontal direction. A spring and a high-voltage fuse 7 are arranged sequentially in the fuse cavity 6. The inner wall of the fuse cavity 6 is provided with a primary high-voltage shielding mesh 2 and a fuse screw sleeve shielding mesh 3 from the inside to the outside, and a gap is left between the primary high-voltage shielding mesh 2 and the fuse screw sleeve shielding mesh 3. The fuse screw sleeve shielding mesh 3 is connected to the primary high-voltage end of the transformer body 1. The open end of the fuse cavity 6 is sealed by an insulating plug 23. A primary high-voltage insulating column 4 is provided on the rear side of the upper part of the rear end of the insulator 10. A primary conductive rod 21 is provided in the primary high-voltage insulating column 4, which abuts against the spring in the fuse cavity 6. A secondary terminal block 8 is provided at the bottom of the insulator 10.

[0032] See Figures 2 to 4 As shown in the embodiment of this utility model, the insulator 10 is made of epoxy resin casting. The voltage transformer body 1, the primary high-voltage shielding mesh 2, and the fuse sleeve shielding mesh 3 are integrally cast with the epoxy resin. The upper ends of the left and right sides of the insulator 10 are tightened, and the lower ends are wide. The fuse cavity 6 is located on the upper part of the insulator 10 and is cylindrical to ensure uniform insulation distance. The front end of the fuse cavity 6 is a cantilever structure. The primary high-voltage insulating column 4 is located vertically upward or horizontally backward on the rear side of the fuse cavity 6 to ensure sufficient insulation distance for the primary high voltage. The secondary terminal block 8 is located in a groove at the bottom of the insulator 10 and is led out through the secondary cable 11; or a square exposed secondary terminal block 14 is provided at the front end of the bottom of the insulator 10, and the secondary terminal block 8 is connected to the square exposed secondary terminal block 14 through the secondary cable 11, making the user's wiring method more flexible.

[0033] Furthermore, the outer surface of the insulator 10 is uniformly sprayed with a metal coating, and a fluorocarbon paint protective layer is sprayed on the outside of the metal coating.

[0034] Furthermore, the front end and top end of the insulator 10 are provided with lifting rings 12, which are connected to the embedded nuts 15 embedded in the insulator 10. The end face of the embedded nuts 15 is in contact with the metal coating on the outer surface of the insulator 10.

[0035] See Figure 1 As shown in the embodiment of this utility model, a primary high-voltage equalizing ring 5 is provided at the upper rear end of the insulator 10. The primary high-voltage equalizing ring 5 is in contact with the metal coating on the outer surface of the insulator 10, ensuring more reliable grounding. The primary conductive rod 21 is located in the middle of the primary high-voltage equalizing ring 5, resulting in a more uniform electric field distribution and a smaller partial discharge. A mounting plate 13 is provided at the root of the primary high-voltage insulating column 4. The mounting plate 13 is connected to the primary high-voltage equalizing ring 5 by bolts. An insulating plug 22 is provided on the outer side of the primary high-voltage insulating column 4. The insulating plug 22 is in close contact with the primary high-voltage insulating column 4 by primary bolts 25. The insulating plug 22 seals and isolates the high voltage, ensuring personal safety during operation.

[0036] Specifically, the primary high-voltage equalizing ring 5 includes a circular ring and multiple mounting inserts welded onto the circular ring; a layer of semi-conductive corrugated paper is half-stacked on the outer side of the circular ring, the outer surface of the mounting inserts is sprayed with semi-conductive paint, and the end face of the mounting inserts is in contact with the metal coating on the outer surface of the insulator 10.

[0037] See Figure 5 As shown in the embodiment of this utility model, the fuse sleeve shielding mesh 3 includes a blind high-voltage shielding mesh 16, a fuse sleeve 17, and a sleeve shielding mesh 18 connected in sequence by spot welding. The fuse sleeve 17 is threadedly connected to the sleeve bolt 24, and the sleeve bolt 24 is connected to the high-voltage fuse 7 by a spring. The insulating blind 23 is located inside the blind high-voltage shielding mesh 16 and is fastened and sealed to the insulator 10 by bolts.

[0038] See Figure 6 and Figure 7 As shown in the embodiment of this utility model, the primary high-voltage shielding mesh 2 includes a primary fuse shielding mesh 19 and a primary conductive rod end cap 20 spot-welded to the rear end of the primary fuse shielding mesh 19. The primary conductive rod end cap 20 is threadedly connected to the primary conductive rod 21, and the threaded connection is welded to make the electrical connection more reliable.

[0039] Furthermore, the outer surfaces of the primary high-voltage shielding mesh 2 and the fuse screw sleeve shielding mesh 3 are uniformly sandblasted and then sprayed with a layer of semi-conductive paint, resulting in better shielding effect.

[0040] The present invention provides a single-phase voltage transformer with a fuse and grounding, the preparation process of which is as follows:

[0041] The secondary winding and primary winding are concentrically wound on an insulating frame and then fitted onto an iron core column. After insulation and buffer wrapping, a voltage transformer body 1 is formed. The voltage transformer body 1, primary high-voltage shielding mesh 2, fuse sleeve shielding mesh 3, and primary high-voltage equalizing ring 5 are fixed in a mold and cast with epoxy resin to form an integral insulator 10 with a primary high-voltage insulating column 4, a secondary terminal block 8, and a fuse cavity 6. Except for the inner surfaces of the primary high-voltage insulating column 4, the fuse cavity 6, and the secondary terminal block 8, the outer surfaces of the insulator 10 are uniformly sprayed with a layer of semi-conductive paint to form a grounding shield, shielding the primary high voltage within the insulator 10. The outermost layer of the insulator 10 is sprayed with silver-white fluorocarbon paint for protection. Finally, the insulator 10 is installed as a whole on a base plate 9. The inner wall of the fuse cavity 6 of this integral structure is shielded and enclosed by the primary high-voltage shielding mesh 2 and the fuse sleeve shielding mesh 3, shielding the high-voltage electric field within the fuse cavity 6. The fuse sleeve shielding mesh 3 is connected to the primary high-voltage terminal of the voltage transformer body 1. Sufficient gaps are maintained between the primary high-voltage shielding mesh 2 and the fuse sleeve shielding mesh 3, ensuring stable insulation and better shielding performance. This guarantees sufficient electrical clearance to isolate the high voltage after the fuse blows in the event of an overcurrent in the system. A metal coating is provided between the outer silver-white fluorocarbon paint protective layer of the insulator 10 and the epoxy resin body. This metal coating contacts the end face of the mounting nut 15 used to fix the lifting ring 12 and the end face of the mounting insert of the primary high-voltage equalizing ring 5, ensuring low-voltage potential balance and better shielding performance. Lifting rings 12 are provided at the front and top of the insulator 10 for convenient product handling and installation.

[0042] In use, the insulating plug 22, which cooperates with the primary high-voltage insulating column 4, achieves mechanical connection with the high-voltage components. The end is fixed with a cylindrical metal terminal and a compressible spring to achieve electrical contact with the high-voltage part in the gas chamber. After the utility model is fixedly installed by the mounting plate 13 and the base plate 9 fixed to the root of the primary high-voltage end of the insulator 10, the secondary cable 11 is connected. After the other high-voltage components of the switch are installed, the installation of this device is completed.

[0043] This utility model presents a small-sized, flexible, fuse-protected, uniform electric field, long maintenance cycle, and widely applicable single-phase voltage transformer with fuse grounding, made of epoxy resin, metal spraying, and silver-white fluorocarbon paint. It is designed entirely according to national standards and the special requirements of switchgear. Using a rolled iron core and the principle of electromagnetic conversion, the secondary voltage accurately reflects the changes in the primary voltage, serving as a voltage measurement and relay protection device. The high-voltage shield consists of a primary high-voltage shielding mesh 2 and a fuse screw sleeve shielding mesh 3, while the primary high-voltage equalizing ring 5 and the insulator 10 are coated with a semi-conductive paint layer to form a low-voltage shield. Together, these components effectively shield the high and low voltage electric fields, resulting in a uniform electric field distribution and low partial discharge. It is suitable for various sulfur hexafluoride gas-filled switchgear, achieving the simplification and miniaturization of switchgear.

[0044] The above description is merely an embodiment of this utility model and is not intended to limit the scope of protection of this utility model. Any modifications, equivalent substitutions, improvements, extensions, etc., made within the spirit and principles of this utility model are included within the scope of protection of this utility model.

Claims

1. A single-phase voltage transformer with a fuse grounding type, comprising an insulator (10) and a transformer body (1) enclosed within the insulator (10), the insulator (10) being mounted on a base plate (9), characterized in that, The upper part of the insulator (10) is provided with a fuse cavity (6) with an open end in the horizontal direction. A spring and a high-voltage fuse (7) are arranged in sequence in the fuse cavity (6). The inner wall of the fuse cavity (6) is provided with a primary high-voltage shielding mesh (2) and a fuse screw sleeve shielding mesh (3) from the inside to the outside, and there is a gap between the primary high-voltage shielding mesh (2) and the fuse screw sleeve shielding mesh (3). The fuse screw sleeve shielding mesh (3) is connected to the primary high-voltage end of the voltage body (1). The open end of the fuse cavity (6) is sealed by an insulating plug (23). The rear side of the upper part of the rear end of the insulator (10) is provided with a primary high-voltage insulating column (4). The primary high-voltage insulating column (4) is provided with a primary conductive rod (21) that abuts against the spring in the fuse cavity (6). The bottom of the insulator (10) is provided with a secondary terminal block (8).

2. The single-phase voltage transformer with fuse grounding according to claim 1, characterized in that, The primary high-voltage shielding mesh (2) includes a primary fuse shielding mesh (19) and a primary conductive rod end cap (20) welded to the rear end of the primary fuse shielding mesh (19). The primary conductive rod end cap (20) is threadedly connected to the primary conductive rod (21), and the threaded connection is welded.

3. The single-phase voltage transformer with fuse grounding according to claim 1, characterized in that, The fuse sleeve shielding mesh (3) includes a high-voltage shielding mesh (16), a fuse sleeve (17), and a sleeve shielding mesh (18) connected in sequence by spot welding. The fuse sleeve (17) is threadedly connected to the sleeve bolt (24), and the sleeve bolt (24) is connected to the high-voltage fuse (7) by a spring. The insulating end cap (23) is located inside the high-voltage shielding mesh (16) and is fastened and sealed to the insulator (10) by bolts.

4. The single-phase voltage transformer with fuse grounding according to claim 1, characterized in that, The outer surfaces of the primary high-voltage shielding mesh (2) and the fuse screw sleeve shielding mesh (3) are uniformly sandblasted and then sprayed with a layer of semi-conductive paint.

5. The single-phase voltage transformer with fuse grounding according to claim 1, characterized in that, The outer surface of the insulator (10) is uniformly sprayed with a metal coating, and a fluorocarbon paint protective layer is sprayed on the outside of the metal coating.

6. The single-phase voltage transformer with fuse grounding according to claim 5, characterized in that, The upper rear end of the insulator (10) is provided with a primary high voltage equalization ring (5), which is in contact with the metal coating on the outer surface of the insulator (10), and the primary conductive rod (21) is located in the middle of the primary high voltage equalization ring (5). The root of the primary high-voltage insulating column (4) is provided with an mounting plate (13), which is connected to the primary high-voltage equalizing ring (5) by bolts. An insulating plug (22) is provided on the outside of the primary high-voltage insulating column (4), and the insulating plug (22) is in close contact with the primary high-voltage insulating column (4) by a primary bolt (25).

7. The single-phase voltage transformer with fuse grounding according to claim 6, characterized in that, The primary high voltage equalization ring (5) includes a circular ring and multiple mounting inserts welded on the circular ring; a layer of semi-conductive crepe paper is stacked on the outer side of the circular ring, the outer surface of the mounting insert is sprayed with semi-conductive paint, and the end face of the mounting insert is in contact with the metal coating on the outer surface of the insulator (10).

8. The single-phase voltage transformer with fuse grounding according to claim 5, characterized in that, The insulator (10) has a lifting ring (12) at its front end and top end. The lifting ring (12) is connected to a nut (15) embedded in the insulator (10). The end face of the nut (15) is in contact with the metal coating on the outer surface of the insulator (10).

9. The single-phase voltage transformer with fuse grounding according to claim 1, characterized in that, The secondary terminal block (8) is located in a groove provided at the bottom of the insulator (10), and the secondary terminal block (8) is led out through a secondary cable (11); Alternatively, a square exposed secondary platform (14) can be provided at the bottom front end of the insulator (10), and the secondary wiring platform (8) can be connected to the square exposed secondary platform (14) through a secondary cable (11).

10. The single-phase voltage transformer with fuse grounding according to claim 1, characterized in that, The insulator (10) is made of epoxy resin casting, and the voltage transformer body (1), primary high voltage shielding mesh (2) and fuse screw sleeve shielding mesh (3) are integrally formed with the epoxy resin casting. The upper ends of the left and right sides of the insulator (10) are narrow and the lower ends are wide. The fuse cavity (6) is located on the upper part of the insulator (10) and is cylindrical. The front end of the fuse cavity (6) is a cantilever structure. The primary high voltage insulating column (4) is located on the rear side of the fuse cavity (6) and is vertically upward or horizontally backward.

Images