Wall bushing

Abstract

The invention relates to the field of pipes and sleeves through which conductors can pass, in particular to a wall bushing. The wall bushing is used for solving the problem that in order to guarantee the insulation characteristic of an existing wall bushing, the size of an insulation sleeve is large due to the fact that the using amount of insulation materials is large. The wall bushing comprises an insulator and a central conductor, a high-voltage shielding piece and a grounding shielding piece which are poured in the insulator, the insulator is provided with a connecting structure used for being connected with a gas tank, the high-voltage shielding piece is located at the position close to the end of the insulator and sleeves the outer side of the central conductor, and the outer contour of the insulator is a smooth curve. The insulator is provided with a protruding part and a concave part, the protruding part is located at the end, away from the connecting structure, of the insulator, the end of the grounding shielding piece and the high-voltage shielding piece on the outer side of the end of the grounding shielding piece are located in the protruding part, and the concave part is arranged corresponding to the position between the end of the grounding shielding piece and the connecting structure. Therefore, on the premise of ensuring the insulativity of the insulator, the use amount of the insulating material is saved, and the size of the insulator is reduced.

Description

Technical Field

[0001] The invention relates to the field of tubes and sleeves through which conductors can pass, and in particular to a wall-penetrating sleeve. Background Art

[0002] Under the background of "double carbon", environmentally friendly and fluorine-free switchgear will have a wide range of application prospects. Insulators are indispensable components of environmentally friendly switchgear, but existing insulators have the problem of large epoxy resin usage and large volume. For example, the Chinese invention patent with application publication number CN117080963A discloses a wall bushing, which includes an insulating sleeve and a central conductor cast in the insulating sleeve. A high-voltage shielding part and a grounding shielding part are also cast in the sleeve of the insulating sleeve. The high-voltage shielding part is sleeved on the central conductor in a cylindrical shape and connected to the central conductor with the same potential, and its two ends extend to positions close to the two end faces of the insulating sleeve respectively; the grounding shielding part is concentrically sleeved outside the central conductor and connected to the metal connecting insert to achieve grounding of the wall bushing. Among them, the high-voltage shielding part is cylindrical and its two ends extend to the end faces of the insulating sleeve. In this way, when pouring the insulating material, the insulating material needs to pass through the gap between the center conductor and the end of the high-voltage shielding cover to enter the gap space between the two to cover the center conductor. The insulating material has a certain consistency, so pouring defects are inevitable during pouring. At the same time, the insulating sleeve is cylindrical. Because the insulating sleeve needs to ensure the insulation properties of the wall sleeve, the thickness of the insulating sleeve needs to be set according to the maximum field strength. In this way, the amount of insulating material used is large and the volume of the insulating sleeve is also large. Summary of the invention

[0003] The object of the present invention is to provide a wall bushing to solve the problem that a large amount of insulating material is used in the existing wall bushing to ensure its insulation properties, resulting in a large volume of the insulating bushing.

[0004] In order to solve the above technical problems, the present invention provides a wall bushing including an insulator and a central conductor cast in the insulator, the insulator having a connection structure for connecting to a gas box, a high-voltage shielding component and a grounding shielding component also cast in the insulator, the grounding shielding component is tubular, the central conductor passes through the grounding shielding component, the high-voltage shielding component is located near the end of the insulator and is sleeved on the outside of the central conductor, the high-voltage shielding component is located axially outside the grounding shielding component, the outer contour of the insulator is a smooth curve, and has a radially protruding bulge and a recessed portion that is concave relative to the bulge, the bulge is located at the end of the insulator away from the connection structure, the end of the grounding shield and the high-voltage shielding component outside the end are both located in the bulge, and the recess is arranged corresponding to the position between the end of the grounding shield and the connection structure.

[0005] The present invention proposes a new technical solution to solve the problem that the amount of insulating material used in the wall bushing in the prior art is large, which eventually leads to a large volume of the insulating sleeve in order to ensure its insulation properties. The high-voltage shielding part is sleeved outside the central conductor and located at the end of the insulator, and an insulator with a bulge and a recessed part is used to cover the high-voltage shielding part, the grounding shielding part and the central conductor therein. The end of the grounding shielding part and the high-voltage shielding part outside the end are both in the bulge, and the recessed part is arranged corresponding to the position between the end of the grounding shielding part and the connection structure. The ends of the high-voltage shielding part and the grounding shielding part (i.e., the high-field strength area) are coated with a thicker insulating layer to ensure the insulation properties of the insulating part, while the position between the end of the grounding shielding part and the connection structure (i.e., the low-field strength area) does not require a thicker insulating material, and a thinner insulating layer can be coated on the outside, so that the amount of insulating material can be saved. The present invention designs the thickness of the insulator according to the surface field strength of the central conductor. Compared with the prior art, the amount of insulating material can be reduced by 15%-20% while ensuring the insulation of the wall bushing, thereby reducing the volume of the insulator.

[0006] Furthermore, the high-voltage shielding member includes a first high-voltage shielding member and a second high-voltage shielding member, the first high-voltage shielding member and the second high-voltage shielding member extend in a direction perpendicular to the axis of the central conductor and are spaced apart along the axis of the central conductor.

[0007] Further, the first high-voltage shielding component is closer to the end of the central conductor, and the diameter of the second high-voltage shielding component is greater than the diameter of the first high-voltage shielding component.

[0008] Furthermore, the first high-voltage shielding component has a bowl-shaped cross-section with an opening toward the end of the center conductor, and the insulator is provided with an annular recess at the junction with the center conductor and the air, and at least part of the annular recess is located within the first high-voltage shielding component.

[0009] Furthermore, the connection structure is located at one end of the insulator, and the high-voltage shielding component is located at the other end of the insulator.

[0010] Furthermore, the connection structure is located in the middle of the insulator, and the high-voltage shielding components are located at both ends of the insulator.

[0011] Furthermore, the center conductor is a cylindrical conductor with an open end, the sealed end of the cylindrical conductor extends from the first end of the insulator, and the open end is sunk into the second end of the insulator. The second end of the insulator has a avoidance hole for avoiding the outgoing cable at a position corresponding to the opening of the cylindrical conductor so that the outgoing cable can be inserted into the cylindrical conductor, and the high-voltage shielding component is located at the first end of the insulator.

[0012] Furthermore, a third high-voltage shielding component is provided at the open end of the center conductor. The cross-section of the third high-voltage shielding component is bowl-shaped, with an opening toward the second end of the insulator and covering the open end of the center conductor inside. The grounding shielding component extends from the connecting structure to the first end and covers the third high-voltage shielding component inside.

[0013] Furthermore, the high voltage shielding component is provided with flow holes which are helpful for the flow pouring of insulating material.

[0014] Furthermore, the high-voltage shielding component includes an annular shielding end and a connecting column connecting the annular shielding end and the central conductor. After the high-voltage shielding component is connected to the central conductor, the space between adjacent connecting columns constitutes the current-passing hole.

[0015] Furthermore, the high-voltage shielding component includes an annular shielding end, the center hole of the annular shielding end is for the center conductor to pass through, the inner wall surface of the center hole is connected to the center conductor, and a through hole is arranged on its annular surface, and the through hole constitutes the current hole.

[0016] Furthermore, the thickness of the annular plate-shaped shielding end gradually increases from the edge to the middle, and there is an arc-shaped transition from the end to the middle.

[0017] Furthermore, the high-voltage shielding component is a shielding net, which includes a vertical extension end which is cylindrically sleeved on the central conductor and a horizontal extension end extending from the end of the vertical extension end, and the mesh of the shielding net constitutes the current-passing hole. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a structural schematic diagram of a partial structure of a wall bushing of the present invention; Figure 2 for Figure 1 Schematic diagram of field strength; Figure 3 This is a schematic structural diagram of a busbar bushing according to a first embodiment of the present invention; Figure 4 It is a structural schematic diagram of a busbar wall bushing according to a second embodiment of the present invention; Figure 5 This is a schematic structural diagram of an outlet bushing according to a third embodiment of the present invention; Figure 6 A schematic diagram of the structure of the busbar bushing, busbar wall bushing and outlet bushing of the present invention being installed at different positions on the box body, the busbar bushing being connected to the busbar cross joint, and the outlet bushing being connected to the outlet cable; Figure 7 It is a schematic structural diagram of a ring-type high-voltage shielding member mounted on a central conductor in a wall bushing of the present invention; Figure 8 for Figure 7 A top view of the mid-ring high voltage shield; Fig. 9 It is a schematic structural diagram of a disc-type high-voltage shielding member mounted on a central conductor in a wall bushing of the present invention; Fig.10 for Fig. 9 A top view of the mid-disk high voltage shield; Fig.11 It is a schematic structural diagram of an arc-shaped disc-type high-voltage shielding member mounted on a central conductor in a wall bushing of the present invention; Fig.12 for Fig.11 A top view of the mid-arc high voltage shield; Fig.13 It is a schematic structural diagram of a mesh-type high-voltage shielding member mounted on a central conductor in a wall bushing of the present invention; Fig.14 for Fig.13 Front view of the central mesh high voltage shield.

[0019] In the figure: 1. insulator; 101. bulging part; 102. recessed part; 2. first high-voltage shielding part; 3. second high-voltage shielding part; 31. annular high-voltage shielding part; 311. connecting column; 32. disc-type high-voltage shielding part; 33. arc-shaped high-voltage shielding part; 34. mesh-type high-voltage shielding part; 4. grounding shielding part; 5. center conductor; 6. third high-voltage shielding part; 7. grounding insert; 8. connector; 9. outer insulator; 10. fixing rivet; 11. conductive O-ring; 12. busbar cross joint; 13. busbar bushing; 14. wall bushing; 15. outlet bushing; 16. outlet cable; 17. air box; 18. annular shielding end; 19. through hole; 20. shielding net. DETAILED DESCRIPTION

[0020] The Chinese invention patent with application publication number CN117080963A discloses a wall bushing, which includes an insulating sleeve and a central conductor cast in the insulating sleeve, a high-voltage shielding part and a grounding shielding part. The high-voltage shielding part is sleeved on the central conductor in a cylindrical shape and connected to the central conductor with the same potential, and the grounding shielding part is concentrically sleeved outside the central conductor and connected to the metal connecting insert. Among them, the insulating sleeve is cylindrical, and because the insulating sleeve needs to ensure the insulation characteristics of the wall bushing, the diameter of the insulating sleeve needs to be set according to the maximum field strength. In this way, the amount of insulating material used is large and the volume of the insulating sleeve is also large.

[0021] The present invention proposes a new technical solution to the problems existing in the above technical solutions. The core concept of the present invention is: a high-voltage shielding part is sleeved outside the central conductor and located at the end of the insulator, and an insulator with a bulge and a recessed part is used to cover the high-voltage shielding part, the grounding shielding part and the central conductor therein, the end of the grounding shielding part and the high-voltage shielding part outside the end thereof are both in the bulge, and the recessed part is arranged corresponding to the position between the end of the grounding shielding part and the connection structure. The ends of the high-voltage shielding part and the grounding shielding part (i.e., the high-field strength area) are coated with a thicker insulation layer to ensure the insulation properties of the insulation part, while the position between the end of the grounding shielding part and the connection structure (i.e., the low-field strength area) does not require a thicker insulation material, and a thinner insulation layer can be coated on the outside, so that the amount of insulation material can be saved. The present invention designs the thickness of the insulator according to the surface field strength of the central conductor. Compared with the prior art, the amount of insulation material can be reduced by 15%-20% while ensuring the insulation of the wall bushing, thereby reducing the volume of the insulator.

[0022] Based on the above invention concept, a wall bushing of the present invention includes: Figure 1 The insulator 1 and the center conductor 5 cast in the insulator 1 are shown. The insulator 1 has a connection structure for connecting to the gas box. A high-voltage shield and a grounding shield 4 are also cast in the insulator 1. The grounding shield 4 is tubular, and the center conductor passes through the grounding shield 4. The connection structure is a grounding insert 7. The grounding shield 4 is connected to the grounding insert 7 to achieve grounding of the wall bushing. The high-voltage shield is located near the end of the insulator 1 and is sleeved on the outside of the center conductor 5. The high-voltage shield in this embodiment is connected to the center conductor 5 through a conductive O-ring 11. The conductive O-ring can not only achieve equipotential connection between the two, but also realize the positioning of the high-voltage shield through the provided groove. In addition, in other embodiments, the high-voltage shield can also be fixed to the center conductor 5 by welding, screw connection, etc. The high-voltage shielding member is located axially outside the grounding shielding member 4. The outer contour of the insulator 1 is a smooth curve, and has a radially protruding bulge 101 and a recessed portion 102 that is concave relative to the bulge 101. The bulge 101 is located at the end of the insulator 1 away from the connection structure. The end of the grounding shielding member 4 and the high-voltage shielding member outside the end are both located in the bulge 101. The recessed portion 102 is arranged corresponding to the position between the end of the grounding shielding member 4 and the connection structure. Figure 2As shown, the ends of the high-voltage shield and the ground shield 4 (i.e., the high-field strength area) are coated with a thicker insulating layer to ensure the insulation properties of the insulating parts, while the position between the end of the ground shield 4 and the connection structure (i.e., the low-field strength area) does not require a thicker insulating material, and a thinner insulating layer can be coated on the outside, so that the amount of insulating material can be saved. The present invention designs the thickness of the insulator according to the surface field strength of the central conductor. Compared with the prior art, the amount of insulating material can be reduced by 15%-20% while ensuring the insulation of the wall bushing, thereby reducing the volume of the insulator.

[0023] In this embodiment, the high voltage shielding element includes: Figure 1 The first high-voltage shielding member 2 and the second high-voltage shielding member 3 shown in the figure extend in a direction perpendicular to the center conductor and are spaced apart along the axial direction of the center conductor 5. The two high-voltage shielding members can more effectively make the electric field around the center conductor 5 uniform, reduce the electric field concentration phenomenon caused by the rough surface of the conductor or casting defects, and help reduce the risk of local discharge and improve the safety and reliability of the equipment. The two high-voltage shielding members can improve the shielding effect of the high-voltage shielding member. At this time, the diameters of the two high-voltage shielding members can be smaller than the diameter of the low-voltage shielding member. In addition, in other embodiments, a high-voltage shielding member may also be used. In order to ensure the shielding effect of the high-voltage shielding member, the diameter of the high-voltage shielding member needs to be roughly the same as the diameter of the low-voltage shielding cover.

[0024] In this embodiment, the first high-voltage shielding member 2 is closer to the end of the center conductor 5, and the diameter of the second high-voltage shielding member 3 is larger than the diameter of the first high-voltage shielding member 2. The second high-voltage shielding member 3 with a larger diameter can cooperate with the first high-voltage shielding member 2 to form a gentle electric field gradient on its outer side, so that it can be adapted to the shape of the bulging portion 101 of the insulator 1 to ensure the insulation properties of the insulator 1.

[0025] In this embodiment, the cross section of the first high-voltage shielding member 2 is bowl-shaped, and the opening is toward the end of the center conductor 5. The insulator 1 is provided with an annular recess at the junction with the center conductor 5 and the air, and at least part of the annular recess is located inside the first high-voltage shielding member 2. The three-phase junction of the center conductor 5, the insulator 1 and the air often leads to field concentration due to casting defects. The annular recess is provided so that the junction moves down to between the first high-voltage shielding member 2 and the center conductor 5. Since the first high-voltage shielding member 2 and the center conductor 5 are connected at the same potential, the electric field between the two is approximately zero, so the field strength at the junction can be effectively controlled within a relatively low range, and the nearby surface electric field is not increased, which effectively solves the problem of surface flashover caused by field concentration due to casting defects at the junction. In addition, in other embodiments, the cross section of the first high-voltage shielding member may also be U-shaped, and the opening is toward the end of the center conductor. It is only necessary to ensure that at least part of the annular recess is located inside the first high-voltage shielding member.

[0026] In such Figure 3 In the embodiment 1 shown, the connection structure is located at one end of the insulator 1, and the high-voltage shielding member is located at the other end of the insulator 1. This kind of wall bushing is called a busbar bushing 13. The central conductor 5 outside the box is covered by the outer insulator 9 in a frustum shape, and can be connected to the outer insulator 9 of the gas box 17. Figure 6 The busbar cross connector 12 shown is electrically connected. The insulator 1 in the box has a radially protruding bulge 101 and a recessed portion 102 that is recessed relative to the bulge 101. The grounding insert 7 used for connecting to the box is located at one end of the insulator 1. The grounding shield 4 is sleeved outside the center conductor and located at one end of the grounding insert, and is electrically connected to the grounding insert 7 through a connector.

[0027] In such Figure 4 In the second embodiment, the connection structure is located in the middle of the insulator 1, and the high-voltage shielding is located at both ends of the insulator 1. This kind of wall bushing is called a busbar wall bushing 14. A first high-voltage shielding 2 and a second high-voltage shielding 3 are provided on the center conductor 5 and at both ends of the insulator 1, and a grounding shielding 4 is sleeved in the middle of the center conductor 5. The grounding shielding 4 and the grounding insert 7 are electrically connected through a connector 8.

[0028] In such Figure 5In the third embodiment, the center conductor 5 is a cylindrical conductor with an open end, the sealed end of the cylindrical conductor extends from the first end of the insulator 1, and the open end is sunk into the second end of the insulator 1. The second end of the insulator 1 has a evacuation hole for evacuating the outlet cable at a position corresponding to the opening of the cylindrical conductor so as to allow the outlet cable to be inserted into the cylindrical conductor, and the high-voltage shielding member is located at the first end of the insulator 1. This kind of wall bushing is called an outlet bushing 15. The outlet cable 16 can pass through the evacuation hole and be electrically connected to the inner wall surface of the center conductor 5. The connection structure of the outlet bushing 15, i.e., the grounding insert 7, is located at the second end of the insulator.

[0029] In the third embodiment, a third high-voltage shielding member 6 is also provided at the open end of the center conductor 5. The cross section of the third high-voltage shielding member 6 is bowl-shaped, with the opening facing the second end of the insulator 1 and covering the open end of the center conductor 5 inside, so that the phenomenon of partial discharge at the open end of the center conductor can be avoided. The grounding shielding member 4 extends from the connection structure to the first end and covers the third high-voltage shielding member 6 inside, and a bending part is provided at one end of the grounding shielding member 4 close to the grounding insert 7, and the bending part of the grounding shielding member 4 is connected to the grounding insert 7 through a fixing rivet 10.

[0030] In this embodiment, the high voltage shielding member is provided with a flow hole which facilitates the flow casting of the insulating material. The flow hole can achieve the lightness of the high voltage shielding member on the one hand, and on the other hand, can make the insulating material with fluidity fully cover the central conductor 5 to avoid the generation of casting defects.

[0031] In a preferred embodiment, the high voltage shielding element comprises: Figure 7 , Figure 8 The annular shielding end 18 and the connecting post 311 connecting the annular shielding end 18 and the center conductor 5 are shown. After the high-voltage shielding part is connected to the center conductor 5, the space between adjacent connecting posts 311 constitutes the flow hole. This high-voltage shielding part is an annular high-voltage shielding part 31. The annular high-voltage shielding part 31 has a simple structure, is easy to manufacture and saves materials. The flow hole formed between adjacent connecting posts can facilitate the flow of insulating materials.

[0032] In a preferred embodiment, the high voltage shielding element comprises: Fig. 9 , Fig.10 The shielding end of the ring plate is shown, and the center hole of the shielding end of the ring plate is for the center conductor to pass through. The inner wall surface of the center hole is connected to the center conductor 5, and the ring surface is provided with a through hole 19, which constitutes the current hole. This high-voltage shielding part is a disc-type high-voltage shielding part 32.

[0033] In a preferred embodiment, if Fig.11 , Fig.12As shown, the thickness of the annular shielding end gradually increases from the edge to the middle, and the end to the middle is an arc-shaped transition. This high-voltage shielding member is an arc-shaped high-voltage shielding member 33. If the angle between the high-voltage shielding member and the center conductor is an acute angle or a right angle, the field strength concentration phenomenon will be caused due to the sudden change in shape. In this embodiment, the junction of the arc-shaped high-voltage shielding member 33 and the center conductor 5 is set to an obtuse angle, which improves the field strength at the junction and avoids the occurrence of local discharge.

[0034] In a preferred embodiment, if Fig.13 , Fig.14 As shown, the high-voltage shielding member is a shielding net 20, which includes a vertical extension end sleeved on the central conductor in a cylindrical shape and a horizontal extension end extending from the end of the vertical extension end, and the mesh of the shielding net constitutes the current-passing hole. This high-voltage shielding member is a mesh-type high-voltage shielding member 34, and the connecting net can be made of existing materials such as metal mesh rolls, which is easy to manufacture and saves costs.

[0035] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. The patent protection scope of the present invention shall be based on the claims. All equivalent structural changes made using the contents of the description and drawings of the present invention should also be included in the protection scope of the present invention.

Claims

1. A wall bushing, characterized in that: It includes an insulator and a center conductor cast in the insulator. The insulator has a connecting structure for connecting to an air box. A high-voltage shielding part and a grounding shielding part are also cast in the insulator. The grounding shielding part is tubular. The center conductor passes through the grounding shielding part. The high-voltage shielding part is located near the end of the insulator and is sleeved on the outside of the center conductor. The high-voltage shielding part is located axially outside the grounding shielding part. The outer contour of the insulator is a smooth curve and has a radially protruding bulge and a recessed part that is concave relative to the bulge. The bulge is located at the end of the insulator away from the connecting structure. The end of the grounding shielding part and the high-voltage shielding part outside the end are both located in the bulge, and the recessed part is arranged corresponding to the position between the end of the grounding shielding part and the connecting structure.

2. The wall bushing according to claim 1, characterized in that: The high-voltage shielding member includes a first high-voltage shielding member and a second high-voltage shielding member. The first high-voltage shielding member and the second high-voltage shielding member extend in a direction perpendicular to the axis of the central conductor and are spaced apart along the axis of the central conductor.

3. The wall bushing according to claim 2, characterized in that: The first high voltage shield is closer to the end of the center conductor, and the diameter of the second high voltage shield is larger than the diameter of the first high voltage shield.

4. The wall bushing according to claim 3, characterized in that: The first high-voltage shielding component has a bowl-shaped cross section with an opening toward the end of the center conductor. The insulator is provided with an annular recess at the junction with the center conductor and the air, and at least part of the annular recess is located in the first high-voltage shielding component.

5. The wall bushing according to claim 4, characterized in that: The connection structure is located at one end of the insulator, and the high-voltage shielding component is located at the other end of the insulator.

6. The wall bushing according to claim 4, characterized in that: The connection structure is located in the middle of the insulator, and the high-voltage shielding components are located at both ends of the insulator.

7. The wall bushing according to claim 5, characterized in that: The center conductor is a cylindrical conductor with one end open. The sealed end of the cylindrical conductor extends from the first end of the insulator, and the open end is sunk into the second end of the insulator. The second end of the insulator has a avoidance hole for avoiding the outgoing cable at a position corresponding to the opening of the cylindrical conductor so that the outgoing cable can be inserted into the cylindrical conductor. The high-voltage shielding component is located at the first end of the insulator.

8. The wall bushing according to claim 7, characterized in that: A third high-voltage shielding component is also provided at the open end of the center conductor. The cross-section of the third high-voltage shielding component is bowl-shaped, with an opening toward the second end of the insulator and covering the open end of the center conductor inside. The grounding shielding component extends from the connecting structure to the first end and covers the third high-voltage shielding component inside.

9. The wall bushing according to claim 1, characterized in that: The high voltage shielding component is provided with flow holes which are helpful for the flow pouring of insulating material.

10. The wall bushing according to claim 9, characterized in that: The high-voltage shielding component comprises an annular shielding end and a connecting post connecting the annular shielding end and the central conductor. After the high-voltage shielding component is connected to the central conductor, the space between adjacent connecting posts constitutes the current-passing hole.

11. The wall bushing according to claim 9, characterized in that: The high-voltage shielding part includes a ring-shaped shielding end, the center hole of the ring-shaped shielding end is for the center conductor to pass through, the inner wall surface of the center hole is connected to the center conductor, and a through hole is arranged on its annular surface, and the through hole constitutes the current hole.

12. The wall bushing according to claim 11, characterized in that: The thickness of the annular plate-shaped shielding end gradually increases from the edge to the middle, and the transition from the end to the middle is in an arc shape.

13. The wall bushing according to claim 9, characterized in that: The high-voltage shielding component is a shielding net, which includes a vertical extension end which is sleeved on the central conductor in a cylindrical shape and a horizontal extension end extending from the end of the vertical extension end. The mesh of the shielding net constitutes the current-passing hole.

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