A self-sealing current transformer for gas-insulated switchgear

Abstract

This invention provides a self-sealing current transformer for gas-insulated switchgear, belonging to the technical field of current transformer structure. It includes a housing assembly and a transformer body. The transformer body includes an integrally cast primary coil and a secondary coil. The housing assembly includes an upper shell and a lower shell. The upper shell has a first terminal block for connecting to the primary coil, and the lower shell has a connecting post. The housing assembly is located within the gas chamber of the gas-insulated switchgear. The connecting post passes through the inner wall of the gas chamber and connects to a sealing cover. A first sealing gasket is provided between the sealing cover and the outer wall of the gas chamber. The secondary connection terminal of the secondary coil passes through the connecting post and connects to a second terminal block on the sealing cover. Only a through hole is left on the outer wall of the gas chamber for the connecting post to pass through. The connecting post serves as the connection base for the current transformer and a channel for the secondary connection terminal to enter the low-voltage area. The sealing cover tightly presses against the first sealing gasket to seal the through hole and the connecting post. This application effectively isolates the high-voltage and low-voltage areas of the gas-insulated switchgear.

Description

Technical Field

[0001] This invention relates to the field of current transformer structure technology, and in particular to a self-sealing current transformer for gas-insulated switchgear. Background Technology

[0002] In the manufacturing of power distribution switchgear and control equipment for power distribution systems and facilities, gas-insulated switchgear, as a key power equipment, is widely used in medium and high voltage power distribution networks. Its core functions are power transmission, distribution, and protection. Cross-linked polyethylene insulated power cables (XLPE cables) and accessories are often used in conjunction with gas-insulated switchgear due to their excellent electrical properties, heat resistance, and mechanical strength.

[0003] Gas-insulated distribution cabinets typically include electronic components such as circuit breakers, contactors, thermal relays, and current transformers. Current transformers are used to convert large currents into smaller currents to facilitate subsequent measurement, protection, and control. See also... Figure 1 A typical current transformer consists of a magnetic core, a primary coil 11 wound on a magnet, and a secondary coil 12. The primary coil 11 is used to connect to the input terminal, and the secondary coil 12 is used to connect to the output terminal. The magnetic core, primary coil 11, and secondary coil 12 are then insulated and cast, and packaged with an insulated shell 101. The shell 101 of the current transformer is then bolted to the inner wall of the gas chamber of the gas-filled cabinet 102. The terminals of the secondary coil 12 also pass through the inner wall of the gas-filled cabinet 102 into the low-voltage area, thereby effectively isolating the high-voltage area and the low-voltage area of ​​the gas-filled cabinet 102 using the current transformer.

[0004] However, the high-voltage chamber of the gas-filled switchgear usually needs to be filled with sulfur hexafluoride gas. The installation of the instrument transformer and the connection between the low-voltage circuit and the second coil terminal all require holes to be made in the inner wall of the gas-filled switchgear. This will increase the difficulty of sealing the gas-filled switchgear chamber. Water and gas can also easily seep into the instrument transformer or even the gas-filled switchgear chamber from the terminal, which can easily cause corrosion of metal parts and, in severe cases, short circuits. Summary of the Invention

[0005] In view of the above problems, the present invention provides a self-sealing current transformer for gas-insulated switchgear.

[0006] To achieve the above-mentioned objectives, the technical solution adopted by this invention is as follows:

[0007] A self-sealing current transformer for gas-insulated switchgear is provided, including a housing assembly and a transformer body;

[0008] The transformer body includes a primary coil and a secondary coil, which are nested together. The primary coil is connected to a primary terminal, and the secondary coil is connected to a secondary terminal.

[0009] The transformer body is located inside the housing assembly, which includes an upper housing and a lower housing. The upper housing and the lower housing are detachably connected. The upper housing is provided with two first terminals, which are connected to the primary terminals. The lower housing has a connecting post, and a sealing cap is threaded to the end of the connecting post away from the lower housing.

[0010] The outer casing assembly is located inside the gas chamber of the gas chamber. The connecting column passes through the inner wall of the gas chamber and connects to the sealing cover. A first sealing gasket is provided between the sealing cover and the outer wall of the gas chamber. A second terminal is provided on the sealing cover. A through hole is coaxially opened inside the connecting column. The secondary connecting terminal passes through the connecting column and connects to the second terminal.

[0011] Furthermore, the upper housing includes an upper inner shell and an upper outer shell, and the lower housing includes a lower inner shell and a lower outer shell. The upper inner shell and the lower inner shell are detachably connected by a first connector. A second sealing gasket is provided on the contact surface between the upper inner shell and the lower inner shell. The upper outer shell and the lower outer shell are detachably connected by a second connector.

[0012] The top of the upper inner shell is integrally provided with a first elastic connecting piece, and the primary terminal and the first terminal head are connected through the first elastic connecting piece. The connecting post is integrally fixed at the bottom of the lower inner shell and passes through the lower outer shell.

[0013] Furthermore, the bottom edge of the lower inner shell is provided with a third sealing gasket for contacting the bottom wall of the lower outer shell, and the bottom edge of the lower outer shell is provided with a fourth sealing gasket for contacting the inner wall of the air chamber.

[0014] Furthermore, the first connecting member is a first connecting piece, which is integrally fixedly connected to the lower inner shell. The first connecting pieces are symmetrically arranged in the middle of the long sides of the lower inner shell. The first connecting piece is used to extend into the upper inner shell. The side of the first connecting piece that is used to contact the inner wall of the upper inner shell is provided with a first ratchet. The inner wall of the upper inner shell is provided with a second ratchet that is adapted to the first ratchet. The first ratchet and the second ratchet cooperate to restrict the separation of the lower inner shell and the upper inner shell.

[0015] The second connecting component is a connecting bolt. Connecting lugs are provided on the outer walls of both the upper and lower outer shells. The connecting bolt passes through the lugs of both the upper and lower outer shells and is then threaded into the nut.

[0016] Furthermore, the second connector is rotatably connected to the sealing cover, and a polygonal guide head is fixedly provided at the end of the second connector near the lower inner shell, while a guide groove adapted to the guide head is provided at the end of the connecting post away from the lower inner shell.

[0017] Furthermore, a rubber pad layer is provided on the inner wall of the guide groove.

[0018] Furthermore, several first guide plates are fixedly installed on the lower inner shell, and several first guide grooves adapted to the first guide plates are vertically opened on the inner wall of the upper inner shell.

[0019] Several second guide plates are fixedly installed on the outer wall of the lower inner shell, and several second guide grooves adapted to the second guide plates are vertically opened on the inner wall of the lower outer shell.

[0020] Furthermore, a pressing strip with a width greater than the width of the second guide plate is provided at one end of the second guide plate near the upper inner shell. A guide surface with an incline is formed between the second guide plate and the pressing strip. An elastic strip is fixedly provided on the upper outer shell. A first pressing part is provided on one side of the elastic strip near the pressing strip, and a snap-fit ​​part is provided on the other side. A limiting part is provided on the inner wall of the lower outer shell. When the upper and lower outer shells are combined, the end of the elastic strip away from the inner bottom wall of the upper outer shell extends into the lower outer shell, and the snap-fit ​​part is located on the side of the limiting part near the inner bottom wall of the lower outer shell. The first pressing part and the pressing strip cooperate to press so that the snap-fit ​​part and the limiting part cooperate to restrict the separation of the upper and lower outer shells.

[0021] Furthermore, the primary coil and the secondary coil are cast together as one piece using insulating resin.

[0022] Furthermore, insulating foam is provided on the inner walls of both the upper and lower inner shells.

[0023] The beneficial effects of the present invention are as follows: 1. The current transformer body is installed inside the outer casing assembly. The primary coil of the current transformer body is connected to the two first terminals of the upper casing. The connecting post on the lower casing passes through the side wall of the gas chamber of the gas filling cabinet and is threadedly connected to the sealing cover. The secondary connecting terminal on the secondary coil of the current transformer body passes through the through hole on the connecting post and is connected to the second terminal on the sealing cover. Only a through hole is left on the outer wall of the gas chamber for the connecting post to pass through. The connecting post is used as the connecting support foot between the current transformer and the gas chamber, and the through hole on the connecting post is used as the channel for the secondary connecting terminal to enter the low-voltage area. When sealing the through hole, the sealing cover is used to press the first sealing gasket to seal the through hole of the gas chamber and the through hole on the connecting post. This can reduce the number of openings on the inner wall of the gas filling cabinet and concentrate on sealing the position where the connecting post passes through the gas filling cabinet, effectively realizing the spatial isolation between the high-voltage area and the low-voltage area of ​​the gas filling cabinet.

[0024] 2. The protection of the current transformer body is divided into two layers: the inner shell group and the outer shell group. The inner shell group is elastically movable relative to the outer shell group. The current transformer body is located inside the inner shell group, which can effectively isolate the current transformer from external impacts during storage and transportation after production, and improve the protection effect of the current transformer body.

[0025] 3. When installing the current transformer, as the sealing cover is tightened, the inner shell assembly can move relative to the outer shell assembly, causing the first elastic connecting piece to extend. The construction personnel can judge whether the inner shell assembly is in close contact with the inner bottom wall of the outer shell assembly by the amount of pressure applied when tightening the sealing cover. When the inner shell assembly is completely against the inner bottom wall of the lower outer shell, that is, the lower outer shell and the sealing cover have worked together to tightly clamp the inner wall of the gas-filled cabinet. At this time, the tightening force of the sealing cover increases sharply, which makes it easier for the construction personnel to judge that the current transformer is installed stably on the inner wall of the gas-filled cabinet.

[0026] 4. After ensuring that the inner shell assembly is moved into place, the first elastic connecting piece can pull the sealing cover to press the first sealing gasket tightly. Even if the sealing cover loosens during the use of the gas cabinet, the elasticity of the first elastic connecting piece can be used to maintain the seal of the hole at the connection column passage on the gas cabinet, which can maintain the sealing effect of the gas chamber in the high-pressure area of ​​the gas cabinet for a long time.

[0027] 5. During the process of fixing the current transformer to the gas-filled cabinet by screwing on the sealing cover, the guide head on the second terminal head cooperates with the guide groove on the connecting column, so that the second terminal head can keep the connecting column in an axial movement manner to seal the connecting column, avoiding the secondary terminal from getting tangled and knotted as the sealing cover rotates. In addition, the guide head cooperates with the rubber pad layer on the inner wall of the guide groove to effectively seal the perforation of the connecting column.

[0028] 6. After merging the upper and lower outer shells and fixing the current transformer in the gas chamber, the extrusion strip on the outer wall of the inner shell assembly presses against the first extrusion part of the outer shell assembly, pushing the latching part to engage with the limiting part. This prevents the upper and lower outer shells from separating while the current transformer is installed in the gas chamber, avoiding safety issues such as current faults caused by maintenance personnel directly disassembling the current transformer installed in the gas chamber. After removing the sealing cover and completely removing the current transformer from the gas cabinet, the inner shell assembly is pulled into the upper outer shell by the elastic force of the first elastic connecting piece. This releases the extrusion strip from the first extrusion part, resets the elastic strip, and disengages the latching part from the limiting part. Only then can the upper and lower outer shells be disassembled, improving the operational safety of the current transformer. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the installation of current transformers in the prior art.

[0030] Figure 2 This is a schematic diagram of the overall structure of the current transformer according to an embodiment of this application.

[0031] Figure 3 This is a schematic diagram of the internal cross-sectional structure of the current transformer according to an embodiment of this application.

[0032] Figure 4 for Figure 3 A magnified view of part A in the diagram.

[0033] Figure 5 This is a schematic diagram of the internal cross-sectional structure of the current transformer according to another perspective of an embodiment of this application.

[0034] Figure 6 for Figure 5 A magnified view of part B in the diagram.

[0035] Figure 7 This is an exploded view of the upper casing according to an embodiment of this application.

[0036] Figure 8 This is an exploded view of the lower casing according to an embodiment of this application.

[0037] Figure 9 This is a schematic diagram showing the connection state between the upper and lower outer shells of the current transformer installed in the gas chamber according to an embodiment of this application.

[0038] Among them, 1. Current transformer body; 11. Primary coil; 111. Primary terminal; 12. Secondary coil; 121. Secondary terminal; 2. Upper housing; 21. First terminal; 22. Upper inner housing; 221. Second ratchet; 222. First guide groove; 23. Upper outer housing; 231. Elastic strip; 232. First pressing part; 233. Buckling part; 24. First elastic connecting piece; 3. Lower housing; 31. Lower inner housing; 311. First connecting piece; 312. First ratchet; 313. First... 314. Guide plate; 315. Extrusion strip; 316. Guide surface; 32. Lower outer shell; 321. Second guide groove; 322. Limiting part; 33. Third sealing gasket; 34. Fourth sealing gasket; 41. Connecting post; 411. Perforation; 412. Guide groove; 42. Sealing cap; 421. Guide head; 43. First sealing gasket; 44. Second wiring head; 5. Second sealing gasket; 61. Connecting lug; 62. Connecting bolt; 7. Insulating foam; 101. Outer shell; 102. Gas filling cabinet. Detailed Implementation

[0039] To better understand the above technical solutions, the following will provide a detailed explanation of the technical solutions in conjunction with the accompanying drawings and specific implementation methods.

[0040] This application discloses a self-sealing current transformer for gas-insulated switchgear, referring to... Figure 2 , Figure 3 , Figure 4 and Figure 5The instrument includes a housing assembly and an instrument transformer body 1. The instrument transformer body 1 includes a primary coil 11 and a secondary coil 12. Specifically, the primary coil 11 is made of high-conductivity strip-shaped flat copper wire and is used to connect to the high-voltage circuit to reduce resistance heating. The secondary coil 12 is composed of copper wire wound on a magnetic surface and is used to connect to the low-voltage circuit. The primary coil 11 and the secondary coil 12 are nested together and vertically cast into one piece with insulation. The insulating resin is specifically epoxy resin to maintain insulation and isolation between the primary coil 11 and the secondary coil 12, and to isolate them from air and moisture. The instrument transformer body 1 also includes two primary terminals 111 and two secondary terminals 121. The two primary terminals 111 are respectively connected to the two ends of the primary coil 11, and the two secondary terminals 121 are respectively connected to the two ends of the secondary coil 12.

[0041] Reference Figure 5 and Figure 6 The outer casing assembly includes an upper casing 2 and a lower casing 3, which are detachably connected. Together, they form a cavity that accommodates the transformer body 1. The upper casing 2 has two first terminals 21, each connected to two primary terminals 111. The lower casing 3 has a connecting post 41 with external threads. A sealing cap 42 is threaded to the end of the connecting post 41 furthest from the lower casing 3. A through hole 411 is formed in the connecting post 41, and a second terminal 44 is provided on the sealing cap 42. A secondary terminal passes through the connecting post 41 and connects to the second terminal 44. When using and installing the current transformer, the housing assembly and the transformer body 1 are placed in the gas chamber of the gas filling cabinet 101, and the connecting post 41 passes through the inner wall of the gas chamber and is then threadedly connected to the sealing cover 42. The outer side of the connecting post 41 is fitted with a first sealing gasket 43, and the sealing cover 42 abuts against the outer wall of the gas filling cabinet 101 through the first sealing gasket 43.

[0042] The first sealing gasket 43 is an insulating rubber sealing gasket. During the installation of the current transformer in this application, only through holes for the two connecting posts 41 to pass through are needed on the air chamber. By sealing the through holes 411 on the connecting posts 41 with the sealing cap 42, the internal sealing of the current transformer can be ensured. Then, by placing the first sealing gasket 43 on the outside of the through holes on the outer wall of the air chamber and the sealing cap 42, the gap between the through holes and the connecting posts 41 can be sealed, thereby maintaining the sealing effect on the air chamber. Furthermore, the primary coil 11 and the secondary coil 12 are wrapped together by epoxy resin casting, which can effectively maintain the insulation distance between the primary coil 11 and the secondary coil 12, and effectively prevent dust and water, maintaining its high precision.

[0043] Reference Figure 7 and Figure 8Furthermore, the upper shell 2 can be composed of an upper inner shell 22 and an upper outer shell 23, and the lower shell 3 can be composed of a lower inner shell 31 and a lower outer shell 32. The upper inner shell 22 and the lower inner shell 31 are detachably connected by a first connector. A second sealing gasket 5 is provided on the contact surface between the upper inner shell 22 and the lower inner shell 31. The upper outer shell 23 and the lower outer shell 32 are detachably connected by a second connector.

[0044] Two first elastic connecting pieces 24 are provided on the top of the upper inner shell 22. The primary terminal 111 and the first terminal 21 are connected through the first elastic connecting pieces 24. The first elastic connecting pieces 24 are inclined Z-shaped, giving both ends of the first elastic pieces a flexible range of motion. The connecting post 41 is integrally fixed to the bottom of the lower inner shell 31 and passes through the lower outer shell 32. Specifically, the two end shells of the first elastic connecting piece 24 are respectively embedded in the top of the upper inner shell 22 and the upper outer shell 23. In use, after the connecting post 41 passes through the lower outer shell 32 and the side wall of the air chamber, it connects with the sealing cover 42. During the connection process, the sealing cover 42 abuts against the outer wall of the air chamber, pulling the lower inner shell 31 and the upper inner shell 22 together closer to the side wall of the air chamber until the lower inner shell 31 abuts against the inner bottom wall of the lower outer shell 32. The double-layer shell assembly can improve the puncture resistance of the transformer body 1 and also improve the dustproof and waterproof effect of the transformer body 1 during daily use.

[0045] Furthermore, a first annular groove is formed on the edge of the bottom wall of the lower inner shell 31, and a third sealing gasket 33 is fixedly embedded in the first annular groove. A second annular groove is formed on the edge of the bottom wall of the lower outer shell 32, and a fourth sealing gasket 34 is fixedly embedded in the second annular groove. The second sealing gasket 5, the third sealing gasket 33, and the fourth sealing gasket 34 can all be made of insulating rubber rings. The second sealing gasket 5 can seal the joint between the upper inner shell 22 and the lower inner shell 31 when they are connected, keeping the environment between the upper inner shell 22 and the lower inner shell 31 closed. The third sealing gasket 33 can seal the gap between the lower inner shell 31 and the inner bottom wall of the lower outer shell 32 when the lower inner shell 31 is forced to move and press against the inner bottom wall of the lower outer shell 32. The fourth sealing gasket 34 can seal the gap between the lower outer shell 32 and the inner wall of the air chamber when the lower outer shell 32 comes into contact with the inner wall of the air chamber. The third sealing gasket 33 and the fourth sealing gasket 34 are used together to completely seal the through hole opened on the gas chamber, so that the gas chamber of the gas filling cabinet 101 is completely isolated from the low-pressure part.

[0046] In this embodiment, the first connector is a first connecting piece 311, which is integrally fixedly connected to the lower inner shell 31. The first connecting piece 311 is symmetrically arranged in the middle of the long sides of both sides of the lower inner shell 31. The first connecting piece 311 is used to extend into the upper inner shell 22. A first ratchet 312 is provided on the side of the first connecting piece 311 that is in contact with the inner wall of the upper inner shell 22. A second ratchet 221 that is adapted to the first ratchet 312 is provided on the inner wall of the upper inner shell 22. The first ratchet 312 and the second ratchet 221 cooperate to restrict the separation of the lower inner shell 31 and the upper inner shell 22. When the lower inner shell 31 and the upper inner shell 22 are fully connected, the first ratchet 312 and the second ratchet 221 are fully engaged. Under this engagement, the gap between the lower inner shell 31 and the upper inner shell 22 should be less than the width of the second sealing gasket 5 in the relaxed state. This ensures that after the lower inner shell 31 and the upper inner shell 22 are fully joined, they maintain pressure on the second sealing gasket 5, improving the sealing effect of the second sealing gasket 5 on the gap between them. The first connecting piece 311 is positioned at the middle of the long side of the lower inner shell 31. This allows, when the upper inner shell 22 and the lower inner shell 31 need to be separated, pressure is applied from the middle of the long sides of the lower inner shell 31, causing deformation on both sides of the lower inner shell 31 at the first connecting piece 311. This disengages the first ratchet 312 from the second ratchet 221, allowing the lower inner shell 31 to separate normally from the upper inner shell 22. In this embodiment, the first connecting piece 311 needs to be placed on the lower inner shell 31. Under normal conditions, the upper inner shell 22 is elastically pulled by the first elastic connecting piece 24 and retracted into the upper outer shell 23, which makes it inconvenient to operate the upper inner shell 22. Only the lower inner shell 31 has operable space.

[0047] The second connecting component can be a connecting bolt 62. Connecting lugs 61 are integrally fixed on the outer walls of both the upper outer shell 23 and the lower outer shell 32. The connecting bolt 62 passes through the connecting lugs 61 on both the upper outer shell 23 and the lower outer shell 32 and is then threadedly connected to the nut.

[0048] Furthermore, to prevent the secondary terminal 121 from being twisted and damaged during the rotational threaded connection between the sealing cap 42 and the connecting post 41, in this embodiment, the second connector 44 is rotatably connected to the sealing cap 42. Specifically, a polygonal guide head 421 is integrally fixed at the end of the second connector 44 near the inner shell, and a guide groove 412 adapted to the guide head 421 is provided at the end of the connecting post 41 away from the lower inner shell 31. The guide head 421 can be made of rubber, and the movement of the sealing cap 42 on the connecting post 41 is provided with elastic allowance to ensure that the sealing cap 42 can cooperate with the lower outer shell 32 to clamp the inner wall of the gas cabinet 101. Alternatively, depending on the thickness of the inner wall of the gas cabinet 101, a first sealing gasket 43 of different thicknesses can be selected to ensure that the perforation 411 on the connecting post 41 can be sealed even when the lower outer shell 32 and the sealing cap 42 are clamped and fixed to the inner wall of the gas cabinet 101. When connecting the sealing cap 42 to the connecting post 41, the guide head 421 is aligned with the guide groove 412 on the connecting post 41 and inserted. When the sealing cap 42 is rotated and fixed on the connecting post 41, the guide head 421 can maintain axial movement with the connecting post 41 under the restriction of the guide groove 412, thus avoiding the secondary wiring terminal 121 from rotating and getting tangled.

[0049] In order to maintain the sealing effect of the sealing cap 42 on the through hole 411 of the connecting post 41, in this embodiment of the application, a rubber pad layer is provided on the inner wall of the guide groove 412, and the guide head 421 can be set as a truncated cone with a taper of 3°~6°. As the guide head 421 continues to move into the connecting post 41, the guide head 421 can fit and squeeze the rubber pad layer to ensure the sealing effect on the through hole 411 of the connecting post 41.

[0050] Furthermore, several first guide plates 313 are fixed on the lower inner shell 31, and several first guide grooves 412 adapted to the first guide plates 313 are vertically formed on the inner wall of the upper inner shell 22. When the lower inner shell 31 and the upper inner shell 22 are connected to each other, the first guide plates 313 and the first guide grooves 412 cooperate with each other to prevent misalignment between the upper inner shell 22 and the lower inner shell 31, and effectively maintain the shape and structure of the upper inner shell 22 during the merging and compression process of the upper inner shell 22 and the lower inner shell 31. Several second guide plates 314 are integrally fixed on the outer wall of the lower inner shell 31, and several second guide grooves 321 adapted to the second guide plates 314 are vertically formed on the inner wall of the lower outer shell 32. When the lower inner shell 31 and the lower outer shell 32 are connected to the upper inner shell 22 and the upper outer shell 23 in sequence, the gap between the lower inner shell 31 and the lower outer shell 32 can be maintained through the cooperation of the second guide plate 314 and the guide groove 412, which plays a role in positioning and stabilizing the lower inner shell 31 and the upper inner shell 22.

[0051] In order to provide sufficient protection for the transformer body 1, in this embodiment, insulating foam 7 is provided on the inner walls of the upper inner shell 22 and the lower inner shell 31. The insulating foam 7 is bonded and fixed to the outer walls of the upper inner shell 22 and the lower inner shell 31. The insulating foam 7 can be any one of polyimide foam, silicone rubber foam, polybenzimidazole foam, etc., and can provide insulation, positioning and flame retardant protection for the transformer body 1.

[0052] Reference Figure 9 To improve the connection stability between the upper outer shell 23 and the upper inner shell 22, an extrusion strip 315 is integrally connected to one end of the guide plate near the upper inner shell 22. The width of the extrusion strip 315 is greater than the width of the second guide plate 314. A sloping guide surface 316 is formed between the second guide plate 314 and the extrusion strip 315. An elastic strip 231 is fixedly provided on the upper outer shell 23. A first extrusion part 232 is provided on one side of the elastic strip 231 near the extrusion strip 315, and a buckling part 233 is provided on the other side. A limiting part 322 is provided on the inner wall of the lower outer shell 32. When the upper outer shell 23 and the lower outer shell 32 are combined, one end of the elastic strip 231 away from the inner bottom wall of the upper outer shell 23 extends into the lower outer shell 32, and the buckling part 233 is located on the side of the limiting part 322 near the inner bottom wall of the lower outer shell 32. After the upper outer shell 23 and lower outer shell 32 are merged and the current transformer is installed on the inner wall of the gas chamber, the upper inner shell 22 and lower inner shell 31 move towards the inner wall of the gas chamber, causing the compression strip 315 to move to one side of the first compression part 232. The first compression part 232 and the compression strip 315 cooperate to compress the upper outer shell 233 and the limiting part 322, thereby preventing the upper outer shell 23 and lower outer shell 32 from separating. Before the current transformer is effectively removed from the gas chamber, the connection between the upper outer shell 23 and lower outer shell 32 can be maintained, preventing the upper outer shell 23 and lower outer shell 32 from being opened before the current transformer is safely removed, thus avoiding various safety accidents.

[0053] During the production of the current transformer, the first elastic connecting piece 24 is first welded to the primary terminal 111 of the transformer body 1. Then, the top end of the first elastic connecting piece 24 is passed through the upper outer shell 23 and bent to form the first terminal head 21. The gap between the first elastic connecting piece 24 and the upper outer shell 23 is sealed and fixed by hot-melting the upper outer shell 23 or by adding additional sealant. Under the elastic force of the first elastic connecting piece 24, the upper inner shell 22 and the transformer body 1 are pulled into the lower outer shell 32. Then, the lower inner shell 31 is installed, so that the secondary terminal 121 of the second coil passes through the connecting post 41. Finally, the lower outer shell 32 is installed, so that the connecting post 41 passes through the lower outer shell 32. When installing the current transformer, the connecting post 41 passes through the inner wall of the gas-insulated cabinet 102, and the secondary terminal 121 is connected to the second terminal 44 by welding and detachable connection. During the process of screwing the sealing cover 42 onto the connecting post 41, the guide head 421 cooperates with the guide groove 412 to seal the connecting post 41 and realize the installation of the connecting post 41 on the gas-insulated cabinet 102 without the secondary terminal 121 rotating and getting tangled. The secondary terminal 121 is compressed in the through hole 411 of the connecting post 41.

[0054] Those skilled in the art will understand that although preferred embodiments of the invention have been described, those skilled in the art, once they understand the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including both the preferred embodiments and all changes and modifications falling within the scope of the invention. Clearly, those skilled in the art can make various alterations and modifications to the invention without departing from its spirit and scope. Thus, if these modifications and modifications of the invention fall within the scope of the claims of the invention and their equivalents, the invention also intends to include these modifications and modifications.

Claims

1. A self-sealing current transformer for gas-insulated switchgear, characterized in that: Includes the housing assembly and the transformer body (1); The transformer body (1) includes a primary coil (11) and a secondary coil (12). The primary coil (11) and the secondary coil (12) are nested together. The primary coil (11) is connected to a primary terminal (111), and the secondary coil (12) is connected to a secondary terminal (121). The transformer body (1) is located inside the housing assembly. The housing assembly includes an upper housing (2) and a lower housing (3). The upper housing (2) and the lower housing (3) are detachably connected. The upper housing (2) is provided with two first terminals (21). The first terminals (21) are connected to the primary terminals (111). The bottom of the lower housing (3) is provided with a connecting post (41). The end of the connecting post (41) away from the lower housing (3) is threaded with a sealing cap (42). The upper housing (2) includes an upper inner housing (22) and an upper outer housing (23). The lower housing (3) includes a lower inner housing (31) and a lower outer housing (32). The upper inner housing (22) and the lower inner housing (31) are detachably connected by a first connector. A second sealing gasket (5) is provided on the contact surface between the upper inner housing (22) and the lower inner housing (31). The upper outer housing (23) and the lower outer housing (32) are detachably connected by a second connector. The top of the upper inner shell (22) is integrally provided with a first elastic connecting piece (24), the primary terminal (111) and the first terminal (21) are connected through the first elastic connecting piece (24), the connecting post (41) is integrally fixedly provided at the bottom of the lower inner shell (31), and the connecting post (41) passes through the lower outer shell (32). The outer casing assembly is disposed in the air chamber of the gas chamber (101). The connecting column (41) passes through the inner wall of the air chamber and is connected to the sealing cover (42). A first sealing gasket (43) is provided between the sealing cover (42) and the outer wall of the air chamber. A second terminal (44) is provided on the sealing cover (42). A through hole (411) is coaxially opened in the connecting column (41). The secondary connection terminal passes through the connecting column (41) and is connected to the second terminal (44).

2. The self-sealing current transformer for gas-insulated switchgear according to claim 1, characterized in that, The bottom wall edge of the lower inner shell (31) is provided with a third sealing gasket (33) for contacting the inner bottom wall of the lower outer shell (32), and the bottom wall edge of the lower outer shell (32) is provided with a fourth sealing gasket (34) for contacting the inner wall of the air chamber.

3. The self-sealing current transformer for gas-insulated switchgear according to claim 1, characterized in that, The first connector is a first connecting piece (311). The first connecting piece (311) is integrally fixedly connected to the lower inner shell (31). The first connecting piece (311) is symmetrically arranged in the middle of the long sides of the lower inner shell (31). The first connecting piece (311) is used to extend into the upper inner shell (22). The side of the first connecting piece (311) that is used to contact the inner wall of the upper inner shell (22) is provided with a first ratchet (312). The inner wall of the upper inner shell (22) is provided with a second ratchet (221) that is adapted to the first ratchet (312). The first ratchet (312) and the second ratchet (221) cooperate to restrict the separation of the lower inner shell (31) and the upper inner shell (22). The second connecting component is a connecting bolt (62). Connecting lugs (61) are provided on the outer walls of both the upper outer shell (23) and the lower outer shell (32). The connecting bolt (62) passes through the connecting lugs (61) on both the upper outer shell (23) and the lower outer shell (32) and is threadedly connected to the nut.

4. The self-sealing current transformer for gas-insulated switchgear according to claim 3, characterized in that, The second connector (44) is rotatably connected to the sealing cap (42). A guide head (421) with a polygonal cross-section is fixedly provided at one end of the second connector (44) near the lower inner shell (31). A guide groove (412) adapted to the guide head (421) is provided at one end of the connecting post (41) away from the lower inner shell (31).

5. The self-sealing current transformer for gas-insulated switchgear according to claim 4, characterized in that, A rubber pad layer is provided on the inner wall of the guide groove (412).

6. The self-sealing current transformer for gas-insulated switchgear according to claim 1, characterized in that, A plurality of first guide plates (313) are fixedly provided on the lower inner shell (31), and a plurality of first guide grooves (222) adapted to the first guide plates (313) are vertically opened on the inner wall of the upper inner shell (22); A plurality of second guide plates (314) are fixedly provided on the outer wall of the lower inner shell (31), and a plurality of second guide grooves (321) adapted to the second guide plates (314) are vertically opened on the inner wall of the lower outer shell (32).

7. The self-sealing current transformer for gas-insulated switchgear according to claim 6, characterized in that, The second guide plate (314) has an extrusion strip (315) with a width greater than that of the second guide plate (314) at one end near the upper inner shell (22). A beveled guide surface (316) is formed between the second guide plate (314) and the extrusion strip (315). An elastic strip (231) is fixedly installed on the upper outer shell (23). The end of the elastic strip (231) near the extrusion strip (315) has a first extrusion part (232) protruding from one side and a snap-fit ​​part (233) protruding from the other side. A limiting part (322) is provided on the inner wall of the lower outer shell (32). When the upper outer shell (23) and the lower outer shell (32) are combined, the end of the elastic strip (231) away from the inner bottom wall of the upper outer shell (23) extends into the lower outer shell (32), and the latching part (233) is located on the side of the limiting part (322) close to the inner bottom wall of the lower outer shell (32). The first pressing part (232) and the pressing strip (315) cooperate to press so that the latching part (233) and the limiting part (322) cooperate to restrict the separation of the upper outer shell (23) and the lower outer shell (32).

8. The self-sealing current transformer for gas-insulated switchgear according to any one of claims 1 to 7, characterized in that, The primary coil (11) and the secondary coil (12) are cast together with insulating resin.

9. The self-sealing current transformer for gas-insulated switchgear according to claim 8, characterized in that, Insulating foam (7) is provided on the inner walls of both the upper inner shell (22) and the lower inner shell (31).

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