A current transformer and GIS

Abstract

The utility model provides a kind of current transformer and GIS, belong to high voltage switch field.The current transformer includes mutual inductor cylinder and flange, the outside of flange is equipped with gasket by fastener, the height of mutual inductor cylinder protruding from the outside of flange is greater than the height of fastener and gasket protruding from the outside of flange, one end of mutual inductor cylinder is provided with tangent outside fillet and inside fillet passing through spacer ring, the radius of inside fillet is ten times to fifteen times of the radius of outside fillet, the junction of inside fillet and mutual inductor cylinder inside surface is located between the outside surface and inside surface of flange.The GIS includes the current transformer described above.The utility model dispenses with shielding ring, but by the design and optimization of mutual inductor cylinder structure, the end of mutual inductor cylinder can replace shielding ring and play the role of shielding isolation between conducting rod and gasket, screw.

Description

Technical Field

[0001] This utility model belongs to the field of high voltage switches, and in particular relates to a current transformer and GIS. Background Technology

[0002] Current transformers are an important component of GIS (Gas Insulators and Transformers). Chinese utility model patent CN219778621U discloses an external current transformer, which includes a transformer housing and a transformer coil mounted on the outside of the housing. The conductive rod of the GIS passes through the transformer housing. A flange is connected to one axial end of the transformer housing. The flange has a stepped hole into which a spacer ring is inserted. The axial end of the transformer housing is inserted into the spacer ring, which serves as insulation between the flange and the transformer housing. A gasket is fixed to the flange with screws, and the gasket engages with the axial end of the spacer ring to prevent the spacer ring from dislodging axially.

[0003] The high potential of the conductive rod poses a risk of tip discharge to the low potential of the stepped holes on the surrounding flange, gaskets, and screw edges. Therefore, the aforementioned external current transformer has a shielding ring fixedly installed at the end of the transformer cylinder to prevent tip discharge. For safe installation of the shielding ring, an annular groove is provided on the inner side of the transformer cylinder end. One end of the shielding ring is embedded in the annular groove, and the inner surface of the shielding ring is flush with the inner surface of the transformer cylinder. Furthermore, the edges of the transformer cylinder end and the shielding ring are rounded to prevent discharge. A countersunk hole is provided on the outer side of the transformer cylinder. A threaded hole corresponding to the countersunk hole is provided at the position where the shielding ring is inserted into the transformer cylinder. A bolt is used to radially pass through the countersunk hole from the outside and connect to the threaded hole on the shielding ring, thus fixing the shielding ring to the transformer cylinder together.

[0004] The addition of a shielding ring in the aforementioned external current transformer increases assembly steps, reduces production efficiency, and raises production costs. During assembly, bolts are needed to fix the shielding ring to the transformer body, increasing the probability of metal shavings being generated. Furthermore, the threaded holes on the shielding ring are through holes, making it easy for metal shavings to fall out and enter the internal cavity of the GIS equipment. The presence of free metal shavings in GIS equipment carrying high voltage will severely affect its insulation performance. Utility Model Content

[0005] The purpose of this utility model is to provide a current transformer to solve the technical problems in the prior art, such as low assembly efficiency, high production cost, and easy generation of free metal shavings that affect the insulation of GIS equipment using the current transformer, caused by fixing the shielding ring to the end of the transformer cylinder with bolts due to shielding requirements.

[0006] Another objective of this invention is to provide a GIS to solve the aforementioned technical problems.

[0007] To achieve the above objectives, the technical solution for the current transformer provided by this utility model is as follows:

[0008] A current transformer includes a transformer body and a flange. The flange has a stepped mounting hole, and a spacer ring is installed in the stepped mounting hole. The transformer body is inserted into the spacer ring. A gasket is installed on the outer side of the flange by fasteners. The gasket is engaged with the axial end of the spacer ring to prevent the spacer ring from coming out. The height of the transformer body protruding from the outer side of the flange is greater than the height of the fasteners and gasket protruding from the outer side of the flange. The end of the transformer body that passes through the spacer ring is provided with a tangent outer fillet and an inner fillet. The radius of the inner fillet is ten to fifteen times the radius of the outer fillet. The junction of the inner fillet and the inner side of the transformer body is located between the outer and inner sides of the flange.

[0009] As a further improvement, the distance from the junction of the outer fillet and the outer side of the transformer cylinder to the outer side of the flange is greater than or equal to the height of the fasteners and gaskets protruding from the outer side of the flange.

[0010] As a further improvement, the radius of the outer fillet is one-quarter to one-third of the end wall thickness of the transformer cylinder.

[0011] As a further improvement, the transformer cylinder includes a main body section and an end section for sealing with the spacer ring. The outer circumferential surface of the end section is a sealing mating surface. The outer diameter of the end section is smaller than the outer diameter of the main body section. A limiting step for limiting the spacer ring is formed at the junction of the outer surface of the end section and the outer surface of the main body section.

[0012] As a further improvement, the step surface of the limiting step is an inclined plane, and the angle between the step surface of the limiting step and the outer surface of the mating section, as well as the angle between the step surface of the limiting step and the outer surface of the main body section, are both obtuse angles.

[0013] The beneficial effects are as follows: The current transformer provided by this utility model is an invention that omits key elements. This current transformer eliminates the shielding ring, but through the design and optimization of the transformer cylinder structure, the end of the transformer cylinder can replace the shielding ring and provide shielding and isolation between the conductive rod, gasket, and screw. Eliminating the shielding ring reduces the number of parts in the current transformer, decreases assembly steps, improves assembly efficiency, and lowers production costs. Furthermore, since the shielding ring is no longer required, threaded through holes are also unnecessary, avoiding the generation of loose metal shavings during assembly and effectively improving the insulation reliability of GIS equipment using this current transformer.

[0014] To achieve the above objectives, the technical solution for GIS provided by this utility model is as follows:

[0015] A GIS includes a busbar cylinder and a current transformer fixed to the busbar cylinder. The current transformer includes a transformer cylinder and a flange. The flange has stepped mounting holes, and a spacer ring is installed in the stepped mounting holes. The transformer cylinder is inserted into the spacer ring. A gasket is installed on the outer side of the flange by fasteners. The gasket is engaged with the axial end of the spacer ring to prevent the spacer ring from falling out. The height of the transformer cylinder protruding from the outer side of the flange is greater than the height of the fasteners and gasket protruding from the outer side of the flange. The end of the transformer cylinder that passes through the spacer ring is provided with a tangent outer fillet and an inner fillet. The radius of the inner fillet is ten to fifteen times the radius of the outer fillet. The junction of the inner fillet and the inner side of the transformer cylinder is located between the outer and inner sides of the flange.

[0016] As a further improvement, the distance from the junction of the outer fillet and the outer surface of the transformer cylinder to the outer side of the flange is greater than or equal to the height of the fasteners and gaskets protruding from the outer side of the flange.

[0017] As a further improvement, the radius of the outer fillet is one-quarter to one-third of the end wall thickness of the transformer cylinder.

[0018] As a further improvement, the transformer cylinder includes a main body section and an end section for sealing with the spacer ring. The outer circumferential surface of the end section is a sealing mating surface. The outer diameter of the end section is smaller than the outer diameter of the main body section. A limiting step for limiting the spacer ring is formed at the junction of the outer surface of the end section and the outer surface of the main body section.

[0019] As a further improvement, the step surface of the limiting step is an inclined plane, and the angle between the step surface of the limiting step and the outer surface of the mating section, as well as the angle between the step surface of the limiting step and the outer surface of the main body section, are both obtuse angles.

[0020] The beneficial effects are as follows: The GIS provided by this utility model is an improvement on the existing technology. The current transformer in this GIS eliminates the shielding ring, but through the design and optimization of the transformer cylinder structure, the end of the transformer cylinder can replace the shielding ring and provide shielding and isolation between the conductive rod, gasket, and screw. Eliminating the shielding ring reduces the number of parts in the current transformer, decreases assembly steps, improves assembly efficiency, and lowers production costs. Furthermore, since the shielding ring is no longer required, threaded through holes are also unnecessary, avoiding the generation of loose metal shavings during assembly and effectively improving the insulation reliability of the GIS equipment. Attached Figure Description

[0021] Figure 1 This is a partial structural schematic diagram of Implementation Method 1 of the GIS in this utility model;

[0022] Figure 2This is a partial structural diagram of the transformer cylinder in Embodiment 1 of the GIS of this utility model.

[0023] Explanation of reference numerals in the attached figures:

[0024] 1. Conductive rod; 2. Current transformer cylinder; 21. Main body section; 22. Mating section; 23. Limiting step; 24. Outer fillet; 25. Inner fillet; 26. Outer ring groove; 3. Flange; 31. Stepped mounting hole; 32. Inner ring groove; 33. Threaded blind hole; 4. Spacer ring; 41. Main ring body; 42. Outer flange; 5. Gasket; 6. Screw; 7. Elastic sealing ring. Detailed Implementation

[0025] The present invention will be further described in detail below with reference to the embodiments.

[0026] To address the problems in the existing technology, the basic concept of this utility model is to design and optimize the structure of the transformer cylinder so that the end of the transformer cylinder can replace the shielding ring and play a shielding and isolation role between the conductive rod, gasket, and screw.

[0027] Implementation method 1 of the GIS provided by this utility model:

[0028] A GIS includes a busbar cylinder and a current transformer, and also includes a conductive rod 1 that passes through the busbar cylinder and the current transformer.

[0029] See appendix Figure 1 The current transformer includes a transformer body 2 and a flange 3. A transformer coil is disposed on the outer side of the transformer body 2. A conductive rod 1 passes through the corresponding transformer body 2 and maintains an insulating distance from the inner surface of the transformer body 2. The transformer body 2 includes a main body section 21 and a mating section 22. The mating section 22 is located at the end of the transformer body 2 used for connection with the flange 3. The transformer coil is disposed on the main body section 21.

[0030] The outer diameter of the mating section 22 is smaller than the outer diameter of the main body section 21. A limiting step 23 is formed at the junction of the outer surface of the mating section 22 and the outer surface of the main body section 21. The step surface of the limiting step 23 is an inclined surface. The angle between the step surface of the limiting step 23 and the outer surface of the mating section 22 and the outer surface of the main body section 21 are both obtuse angles.

[0031] The flange 3 has a stepped mounting hole 31 through which the transformer cylinder 2 passes. The portion of the stepped mounting hole 31 near the outside of the current transformer is a large-diameter section, and the portion near the inside of the current transformer is a small-diameter section. A spacer ring 4 is inserted into the stepped mounting hole 31. The spacer ring 4 includes a main ring body 41, and an outer flange 42 is provided on the outer side of one axial end of the main ring body 41, which is fitted with the large-diameter section of the stepped mounting hole 31. The mating section 22 of the transformer cylinder 2 is inserted into the spacer ring 4, and the limiting step 23 on the transformer cylinder 2 can limit the spacer ring 4 axially.

[0032] The stepped mounting hole 31 serves to stop the spacer 4. A gasket 5 is fixedly mounted on the outer side of the flange 3 by fasteners. The gasket 5 engages with the axial end of the spacer 4 to prevent the spacer 4 from coming out of the stepped mounting hole 31. The fastener is a screw 6. A threaded blind hole 33 is provided at a corresponding position on the flange 3. The screw 6 passes through the gasket 5 and is inserted into the threaded blind hole 33.

[0033] The stepped mounting hole 31 has an inner annular groove 32 on its wall surface, and the mating section 22 of the transformer cylinder 2 has an outer annular groove 26 on its outer surface. Both the inner annular groove 32 and the outer annular groove 26 contain elastic sealing rings 7. These sealing rings are used to seal against the inner and outer surfaces of the spacer ring 4, preventing leakage of insulating gas. To further enhance the sealing effect, the outer circumferential surface of the mating section 22 is precision-machined to form a sealing mating surface.

[0034] The end of the mating section 22 on the transformer cylinder 2 passes through the spacer ring 4 from the inside out and protrudes from the outer side of the flange 3. The height of the transformer cylinder 2 protruding from the outer side of the flange 3 is greater than the height of the fasteners and gaskets 5 protruding from the outer surface of the flange 3, so that the transformer cylinder 2 can effectively isolate and shield between the conductive rod 1 and the fasteners and gaskets 5. In a specific embodiment of this invention, the height of the transformer cylinder 2 protruding from the outer side of the flange 3 can be 19mm, which can ensure good shielding and isolation while avoiding material waste.

[0035] See appendix Figure 1 and in conjunction with the appendix Figure 2The mating section 22 on the transformer cylinder 2 has tangent outer and inner rounded corners 25 at its end. The edge of the outer rounded corner away from the inner rounded corner 25 is tangent to the outer surface of the mating section 22, and the edge of the inner rounded corner 25 away from the outer rounded corner is tangent to the inner surface of the mating section 22. The purpose of setting the inner and outer rounded corners is to make the electric field distribution on the path from inside to outside the transformer cylinder 2 uniform, avoid the distortion of the surrounding electric field distribution, and thus enable the end of the transformer cylinder 2 to completely shield the high potential of the conductive rod 1 from the low potential of the edges of the surrounding flange 3, screw 6, and gasket 5, and improve the electric field strength of the three-way junction area composed of the transformer cylinder 2, spacer ring 4, and insulating gas, which plays an important role in controlling foreign object-induced discharge. In addition, the outer rounded corners also guide the insertion of the transformer cylinder 2 into the spacer ring 4, improving assembly efficiency.

[0036] The radius of the inner fillet 25 is ten to fifteen times that of the outer fillet, and the distance from the junction of the outer fillet and the outer surface of the mating section 22 to the outer side of the flange 3 is greater than or equal to the height of the fastener and gasket 5 protruding from the outer side of the flange 3. The junction of the inner fillet 25 and the inner side of the mating section 22 is located between the outer and inner sides of the flange 3. This arrangement allows the inner fillet 25 to have sufficient axial coverage, thereby making the surrounding electric field change more gradual and the electric field distribution more uniform, further enhancing the shielding effect.

[0037] The radius of the outer fillet is one-quarter to one-third of the end wall thickness of the transformer cylinder 2 (the wall thickness of the mating section 22 of the transformer cylinder 2). This ensures that the outer fillet has a sufficiently large size to avoid the formation of a pointed or near-pointed structure at the end of the transformer cylinder 2, while also ensuring that the inner fillet 25 has a sufficiently large coverage area.

[0038] In one specific embodiment of this implementation, the radius of the outer rounded corner is 5mm and the radius of the inner rounded corner 25 is 50mm. These values ​​are verified by electric field simulation calculation and insulation type test, and can meet the shielding and isolation requirements of the transformer cylinder 2 for the conductive rod 1, the gasket 5 and the screw 6.

[0039] Compared to existing technologies, the current transformer in this GIS eliminates the need for a shielding ring. However, through the design and optimization of the transformer cylinder 2 structure, the end of the transformer cylinder 2 can replace the shielding ring and provide shielding and isolation between the conductive rod 1, the gasket 5, and the screw 6. Eliminating the shielding ring reduces the number of parts in the current transformer, decreases assembly steps, improves assembly efficiency, and lowers production costs. Furthermore, since the shielding ring is no longer required, threaded through holes are also unnecessary, preventing the generation of loose metal shavings during assembly and effectively improving the insulation reliability of the GIS equipment.

[0040] Embodiment 2 of the GIS provided by this utility model:

[0041] This embodiment is based on Embodiment 1. The difference between this embodiment and Embodiment 1 is that the step surface of the limiting step is not inclined. However, the step surface of the limiting step and the outer surface of the mating section, as well as the outer surface of the main body section, are all rounded to avoid sharp edges that could cause discharge risk.

[0042] Embodiment 3 of the GIS provided by this utility model:

[0043] This embodiment is based on Embodiment 1. The difference between this embodiment and Embodiment 1 is that the outer diameter of the mating section is larger than the outer diameter of the main body section. This allows the wall thickness of the mating section to be greater than the wall thickness of the main body section, which can make the radii of the inner and outer rounded corners larger, which is more conducive to the homogenization of the electric field.

[0044] Implementation method 4 of the GIS provided by this utility model:

[0045] This embodiment is based on Implementation Method 1, but differs from Implementation Method 1 in that...

[0046] The embodiment of the current transformer provided by this utility model:

[0047] The current transformer is the same as the current transformer in the specific implementation of the GIS described above, and will not be described in detail again.

[0048] Finally, it should be noted that the above description is only a preferred embodiment of this utility model and is not intended to limit this utility model. Although this utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art can still make modifications to the technical solutions described in the foregoing embodiments without creative effort, or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A current transformer, characterized in that, The device includes a current transformer housing and a flange. The flange has stepped mounting holes, and a spacer ring is installed inside the stepped mounting holes. The current transformer housing is inserted into the spacer ring. A gasket is installed on the outer side of the flange by fasteners. The gasket and the axial end of the spacer ring are engaged to prevent the spacer ring from coming out. The height of the current transformer housing protruding from the outer side of the flange is greater than the height of the fasteners and gasket protruding from the outer side of the flange. The end of the current transformer housing that passes through the spacer ring is provided with a tangent outer fillet and an inner fillet. The radius of the inner fillet is ten to fifteen times the radius of the outer fillet. The junction of the inner fillet and the inner side of the current transformer housing is located between the outer and inner sides of the flange.

2. The current transformer according to claim 1, characterized in that, The distance from the junction of the outer fillet and the outer side of the transformer cylinder to the outer side of the flange is greater than or equal to the height of the fasteners and gaskets protruding from the outer side of the flange.

3. The current transformer according to claim 1 or 2, characterized in that, The radius of the outer fillet is one-quarter to one-third of the end wall thickness of the transformer cylinder.

4. The current transformer according to claim 1 or 2, characterized in that, The transformer cylinder includes a main body section and an end section for sealing with the spacer ring. The outer circumferential surface of the end section is the sealing mating surface. The outer diameter of the end section is smaller than the outer diameter of the main body section. A limiting step for limiting the spacer ring is formed at the junction of the outer surface of the end section and the outer surface of the main body section.

5. The current transformer according to claim 4, characterized in that, The step surface of the limiting step is an inclined plane, and the angle between the step surface of the limiting step and the outer surface of the mating section, as well as the angle between the step surface of the limiting step and the outer surface of the main body section, are both obtuse angles.

6. A GIS, comprising a busbar cylinder and a current transformer fixed to the busbar cylinder, characterized in that, The current transformer includes a transformer body and a flange. The flange has stepped mounting holes, and a spacer ring is installed in the stepped mounting holes. The transformer body is inserted into the spacer ring. A gasket is installed on the outside of the flange by fasteners. The gasket and the axial end of the spacer ring are locked together to prevent the spacer ring from coming out. The height of the transformer body protruding from the outer side of the flange is greater than the height of the fasteners and gaskets protruding from the outer side of the flange. The end of the transformer body that passes through the spacer ring is provided with a tangent outer fillet and an inner fillet. The radius of the inner fillet is ten to fifteen times the radius of the outer fillet. The junction of the inner fillet and the inner side of the transformer body is located between the outer and inner sides of the flange.

7. The GIS according to claim 6, characterized in that, The distance from the junction of the outer fillet and the outer surface of the transformer cylinder to the outer side of the flange is greater than or equal to the height of the fasteners and gaskets protruding from the outer side of the flange.

8. The GIS according to claim 6 or 7, characterized in that, The radius of the outer fillet is one-quarter to one-third of the end wall thickness of the transformer cylinder.

9. The GIS according to claim 6 or 7, characterized in that, The transformer cylinder includes a main body section and an end section for sealing with the spacer ring. The outer circumferential surface of the end section is the sealing mating surface. The outer diameter of the end section is smaller than the outer diameter of the main body section. A limiting step for limiting the spacer ring is formed at the junction of the outer surface of the end section and the outer surface of the main body section.

10. The GIS according to claim 9, characterized in that, The step surface of the limiting step is an inclined plane, and the angle between the step surface of the limiting step and the outer surface of the mating section, as well as the angle between the step surface of the limiting step and the outer surface of the main body section, are both obtuse angles.

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