Current transformer

Abstract

The utility model discloses a current transformer, and belongs to a current mutual inductance device based on a GIS (Gas Insulated Switchgear) technology. The current shielding device comprises a current shielding cylinder, a shielding cover and a plurality of threaded connection structures, the current shielding cylinder comprises a main body circular tube section and an end circular tube section, the end circular tube section is arranged at one end of the main body circular tube section, the inner diameter of the end circular tube section is larger than that of the main body circular tube section, and the end circular tube section is provided with a plurality of first positioning holes. A first positioning hole is formed in one end of the current shielding cylinder, a second positioning hole is formed in one end of the shielding cover, the first positioning hole, the second positioning hole and the threaded connection structure are correspondingly arranged, and the threaded connection structure fixedly connects the current shielding cylinder and the shielding cover at the first positioning hole and the second positioning hole; the threaded connection structure and the shielding cover do not protrude out of the curved surface where the inner surface of the main body circular tube section is located. According to the utility model, the cleanliness, the reliability and the safety of the equipment are improved.

Description

Technical Field

[0001] The utility model relates to a current mutual inductor device used in GIS products, in particular to a current mutual inductor. Background Art

[0002] Current transformers are essential components in GIS (Gas Insulated Combined Electrical Equipment). Typically, a GIS current transformer consists of a current shielding tube, a shielding case, a primary conductor, and a current coil. The shielding case is attached to the current shielding tube, and the shielding case is tilted outward relative to the current shielding tube. The primary conductor passes through the axis of the current shielding tube and the shielding case, and the current coil is sheathed on the outer wall of the current shielding tube.

[0003] In the existing technology, the shielding cover is riveted to one end of the current shielding tube. The current shielding tube and the shielding cover are made of aluminum alloy. The riveting process easily generates metal debris, which is difficult to clean in the holes formed by the rivets, posing a potential discharge hazard to subsequent tests and GIS operation. Utility Model Content

[0004] The purpose of the utility model is to solve the safety problem caused by debris generated during the assembly process of the current transformer. To this end, the utility model provides a current transformer.

[0005] The technical solution of the utility model is as follows:

[0006] A current transformer includes a current shielding tube, a shielding cover and several threaded connection structures, the current shielding tube includes a main circular tube section and an end circular tube section, the end circular tube section is arranged at one end of the main circular tube section, and the inner diameter of the end circular tube section is larger than the inner diameter of the main circular tube section, the end circular tube section is provided with several first positioning holes, and one end of the shielding cover is provided with a second positioning hole, the first positioning hole, the second positioning hole and the threaded connection structure are correspondingly arranged, the threaded connection structure detachably fixes the current shielding tube and the shielding cover at the first positioning hole and the second positioning hole, and on the inner side of the current shielding tube, the threaded connection structure and the shielding cover do not protrude from the curved surface where the inner surface of the main circular tube section is located.

[0007] As an optional solution, the threaded connection structure includes a fixing bolt and a fixing nut, the first positioning hole and the second positioning hole are light holes, the fixing bolt passes through the first positioning hole and the second positioning hole, and the fixing nut is threadedly connected to the fixing bolt from the outside of the current shielding tube.

[0008] As an optional solution, a thread locking layer is provided between the fixing bolt and the fixing nut to improve the reliability of the connection and reduce the risk of loosening due to vibration during transportation.

[0009] As an optional solution, a flat washer is sleeved on the fixing bolt, and the flat washer is located between the fixing nut and the outer surface of the current shielding cylinder.

[0010] As an optional solution, the fixing bolt is a CM-type hexagonal flat head bolt, and the head end of the fixing bolt is sunk into the second positioning hole.

[0011] As an optional solution, the threaded connection structure adopts a countersunk screw, the first positioning hole adopts a threaded hole, and the countersunk screw is threadedly connected to the first positioning hole.

[0012] As an optional solution, one end of the shielding cover abuts against the end surface of the main body circular tube section, and the second positioning holes are evenly arranged on the shielding cover.

[0013] As an optional solution, the current shielding tube and the shielding cover are made of aluminum alloy, and the threaded connection structure is made of stainless steel.

[0014] As an optional solution, the current transformer also includes a coil, a shell, a conductor and a pot-type insulator; the coil is sleeved on the current shielding tube; the current shielding tube is fixedly connected to the shell from the inner side, the conductor passes through the current shielding tube and is connected to the pot-type insulator, and the pot-type insulator is fixedly connected to the shell.

[0015] As an optional solution, the shell is a hollow structure with two ends open, the current shielding tube partially extends out of the shell, and the shielding cover is located outside the shell.

[0016] The utility model has at least the following beneficial effects:

[0017] 1. Since the first positioning hole and the second positioning hole are opened before assembly, if there is debris on the edge of the hole, it can be cleaned before assembly. The threaded connection structure itself does not contain metal debris, and no debris will be generated during the threaded connection process. Therefore, after the threaded connection structure is used to fix the current shielding tube and the shielding cover, no metal debris will be generated at the connection position, reducing the risk of internal discharge, thereby improving the cleanliness and safety of the equipment.

[0018] 2. Riveting can cause deformation of the current shielding tube and shielding cover, and the structural strength is affected by more factors. Structural strength is not fully controllable, making it prone to damage during transportation. The present invention, however, uses a threaded connection to secure the shielding cover to the current shielding tube. This allows for precise preload at the threaded connection during assembly, making the structural strength of the current shielding tube and shielding cover controllable and standardized. This control of structural strength reduces the risk of damage during transportation, resulting in greater reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The technical features and advantages of the present invention will be more fully understood by referring to the following detailed description in conjunction with the accompanying drawings.

[0020] Figure 1 It is a cross-sectional view of the current transformer of the first embodiment of the present utility model.

[0021] Figure 2 yes Figure 1 Magnified view of part A.

[0022] Figure 3 It is a partial enlarged view of the second embodiment of the present utility model.

[0023] Reference numerals:

[0024] 1. Current shielding tube; 11. Main circular tube section; 12. End circular tube section; 13. First positioning hole; 14. Flanged edge; 2. Shielding cover; 21. Second positioning hole; 3. Threaded connection structure; 31. Fixing bolt; 32. Fixing nut; 33. Flat washer; 34. Countersunk screw; 4. Coil; 5. Housing; 51. Inner step; 6. Conductor; 7. Basin insulator. DETAILED DESCRIPTION

[0025] Unless otherwise defined, the technical or scientific terms used in this specification and claims should have the common meanings understood by persons having ordinary skills in the technical field to which the present invention belongs.

[0026] Example 1

[0027] refer to Figure 1 and Figure 2 This embodiment provides a current transformer for use in GIS products. The current transformer includes a current shielding tube 1, a shielding cover 2, and several threaded connection structures 3.

[0028] The current shielding tube 1 includes a main circular tube section 11 and an end circular tube section 12. The end circular tube section 12 is provided at one end of the main circular tube section 11, and the inner diameter of the end circular tube section 12 is larger than the inner diameter of the main circular tube section 11. Therefore, a step is formed at the connection position between the main circular tube section 11 and the end circular tube section 12, and the step can be used to axially position the shielding cover 2. The outer diameters of the main circular tube section 11 and the end circular tube section 12 are equal, and there is no step on the outer surface; the main circular tube section 11 and the end circular tube section 12 are coaxially arranged. The main circular tube section 11 and the end circular tube section 12 can be processed from a single circular tube, for example, by milling a step on the inner side of one end of the circular tube, thereby forming the main circular tube section 11 and the end circular tube section 12.

[0029] A plurality of first positioning holes 13 are evenly arranged on the end circular tube section 12, and a second positioning hole 21 is evenly provided on one end of the shielding cover 2. The first positioning holes 13, the second positioning holes 21 and the threaded connection structure 3 are correspondingly arranged, that is, one first positioning hole 13 corresponds to one second positioning hole 21 and one threaded connection structure 3. The threaded connection structure 3 fixes the current shielding tube 1 and the shielding cover 2 at the first positioning hole 13 and the second positioning hole 21. During assembly, the shielding cover 2 is axially positioned against the step on the inner side of the current shielding tube 1, and each first positioning hole 13 and the corresponding second positioning hole 21 are coaxial, and then fixed using the threaded connection structure 3. After assembly, on the inner side of the current shielding tube 1, the threaded connection structure 3 and the shielding cover 2 do not protrude from the curved surface of the inner surface of the main circular tube section 11, so as to avoid affecting the electric field inside the current shielding tube 1.

[0030] In this embodiment, the threaded connection structure 3 includes a fixing bolt 31, a fixing nut 32, and a flat washer 33. The first positioning hole 13 and the second positioning hole 21 are smooth holes. The fixing bolt 31 passes through the first positioning hole 13 and the second positioning hole 21. The head of the fixing bolt 31 is located on the inner side of the current shielding tube 1. The fixing nut 32 is threadedly connected to the fixing bolt 31 from the outer side of the current shielding tube 1. The flat washer 33 is located on the outer side of the current shielding tube 1 and is sleeved on the fixing bolt 31. The flat washer 33 is clamped between the fixing nut 32 and the outer surface of the current shielding tube 1. In addition, a thread locking layer is provided between the fixing bolt 31 and the fixing nut 32. The thread locking layer can be formed by applying a thread locking agent to the outer thread of the fixing bolt 31 or the inner thread of the fixing nut 32. The thread locking layer improves the reliability of the connection and reduces the risk of loosening due to vibration during transportation. In addition, in this embodiment, the fixing bolt 31 is a CM-type hexagonal flat head bolt, the second positioning hole 21 is a stepped hole, and the head end of the fixing bolt 31 is sunk into the second positioning hole 21, that is, on the inner side of the current shielding tube 1, and the fixing bolt 31 does not protrude from the inner surface of the end circular tube section 12.

[0031] In terms of material, the current shielding tube 1 and the shielding cover 2 are made of aluminum alloy, and the threaded connection structure 3 is made of stainless steel to ensure the stability and durability of the connection.

[0032] In this embodiment, the current transformer also includes a coil 4, a housing 5, a conductor 6, and a pot-type insulator 7. The coil 4 is mounted on the current shielding tube 1. Multiple coils 4 are arranged closely along the axial direction of the current shielding tube 1 and distributed from one end to the other. The housing 5 is a hollow structure with both ends open. One end of the current shielding tube 1 is fixedly connected to it from the inside of the housing 5. Specifically, the connection method can be: one end of the current shielding tube 1 is turned outward to form a flange 14, and the inside of the housing 5 is provided with an inner step 51. The flange 14 is fixed directly to the inner step 51 or fixed to the inner step 51 via a mounting plate. The other end of the current shielding tube 1 extends outward from the housing 5. Accordingly, the shielding cover 2 is located outside the housing 5, and part of the coil 4 is also located outside the housing 5. The conductor 6 extends through the current shielding tube 1 and is coaxial with the conductor 6. The end of the conductor 6 located inside the housing 5 is fixedly connected to the pot-type insulator 7. The pot-type insulator 7 is fixedly connected to the end of the housing 5, and the pot-type insulator 7 is partially located inside the housing 5 to facilitate connection with the conductor 6.

[0033] Example 2

[0034] refer to Figure 3 understand, Figure 3 This is a partial enlarged view illustrating the connection between the current shield tube 1 and the shield cover 2 in this embodiment. This embodiment differs from the first embodiment in the threaded connection structure 3. In this embodiment, the threaded connection structure 3 utilizes a countersunk screw 34, and the first positioning hole 13 is a threaded hole. The countersunk screw 34 is threadedly connected to the first positioning hole 13. A threadlocker is applied to the connecting area to form a threadlocking layer, enhancing reliability. Inside the current shield tube 1, the end face of the countersunk screw 34 is flush with the surface of the shield cover 2.

[0035] The other parts of this embodiment are the same as those of the first embodiment and will not be described in detail here.

[0036] In Examples 1 and 2, since the first positioning hole 13 and the second positioning hole 21 are already formed before assembly, any debris on the edges of the holes can be cleaned off during assembly. The threaded connection structure 3 itself does not contain metal debris, nor does it generate debris during the threaded connection process. Therefore, after the current shielding tube 1 and the shielding cover 2 are secured using the threaded connection structure 3, no metal debris is generated at the connection point, reducing the risk of internal discharge and thereby improving the cleanliness and safety of the equipment. Furthermore, riveting can cause deformation of the current shielding tube 1 and the shielding cover 2 themselves, and more factors affect the structural strength. The structural strength is not fully controllable, and is prone to damage during transportation. The present invention, however, uses a threaded connection structure 3 to secure the shielding cover 2 to the current shielding tube 1, enabling accurate preload at the threaded connection during assembly. This allows for controllable and standardized structural strength of the current shielding tube 1 and the shielding cover 2. By controlling the structural strength, the risk of damage during transportation is reduced, resulting in higher reliability. Furthermore, compared to vertical riveting, the present invention reduces assembly difficulty and facilitates cleaning.

[0037] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the present invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the present invention. Therefore, the embodiments should be considered in all respects as illustrative and non-restrictive, and the scope of the present invention is defined by the appended claims, not the foregoing description, and all variations within the meaning and range of equivalents of the claims are intended to be encompassed within the present invention. Any reference sign in a claim should not be construed as limiting the claim to which it relates.

Claims

1. A current transformer, characterized in that: It includes a current shielding tube, a shielding cover and several threaded connection structures. The current shielding tube includes a main circular tube section and an end circular tube section. The end circular tube section is arranged at one end of the main circular tube section, and the inner diameter of the end circular tube section is larger than the inner diameter of the main circular tube section. The end circular tube section is provided with several first positioning holes, and one end of the shielding cover is provided with a second positioning hole. The first positioning hole, the second positioning hole and the threaded connection structure are correspondingly arranged. The threaded connection structure fixes the current shielding tube and the shielding cover detachably at the first positioning hole and the second positioning hole. On the inner side of the current shielding tube, the threaded connection structure and the shielding cover do not protrude from the curved surface where the inner surface of the main circular tube section is located.

2. The current transformer according to claim 1, characterized in that: The threaded connection structure includes a fixing bolt and a fixing nut. The first positioning hole and the second positioning hole are light holes. The fixing bolt passes through the first positioning hole and the second positioning hole. The fixing nut is threadedly connected to the fixing bolt from the outside of the current shielding cylinder.

3. The current transformer according to claim 2, characterized in that: A thread locking layer is provided between the fixing bolt and the fixing nut.

4. The current transformer according to claim 2, characterized in that: A flat washer is sleeved on the fixing bolt, and the flat washer is located between the fixing nut and the outer surface of the current shielding cylinder.

5. The current transformer according to claim 2, characterized in that: The fixing bolt is a CM-type hexagonal flat head bolt, and the head end of the fixing bolt is sunk into the second positioning hole.

6. The current transformer according to claim 1, characterized in that: The threaded connection structure adopts a countersunk screw, the first positioning hole adopts a threaded hole, and the countersunk screw is threadedly connected to the first positioning hole.

7. The current transformer according to any one of claims 1 to 6, characterized in that: One end of the shielding cover rests on the end surface of the main body circular tube section, and the second positioning holes are evenly arranged on the shielding cover.

8. The current transformer according to any one of claims 1 to 6, characterized in that: The current shielding tube and the shielding cover are made of aluminum alloy, and the threaded connection structure is made of stainless steel.

9. The current transformer according to any one of claims 1 to 6, characterized in that: The current transformer also includes a coil, a shell, a conductor and a pot-type insulator; the coil is sleeved on the current shielding tube; the current shielding tube is fixedly connected to the shell from the inner side, the conductor passes through the current shielding tube and is connected to the pot-type insulator, and the pot-type insulator is fixedly connected to the shell.

10. The current transformer according to claim 9, characterized in that: The shell is a hollow structure with two ends open, the current shielding tube partially extends out of the shell, and the shielding cover is located outside the shell.

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