Self-sealing current transformer for gas insulated switchgear

Abstract

The invention provides a self-sealing current transformer for a gas insulated switchgear, and belongs to the technical field of current transformer structures. Comprising a shell assembly and a transformer body. The mutual inductor body comprises a primary coil and a secondary coil which are integrally formed through pouring, the shell assembly comprises an upper shell and a lower shell, the upper shell is provided with a first connector lug connected with the primary coil, the lower shell is provided with a connecting column, the shell assembly is arranged in an air chamber of the gas-filled cabinet, and the connecting column penetrates through the inner wall of the air chamber and then is connected with a plugging cover. A first sealing gasket is arranged between the plugging cover and the outer wall of the air chamber, and a secondary connecting terminal of the secondary coil penetrates through the connecting column and then is connected with a second connector lug on the plugging cover. The through hole allowing the connecting column to penetrate through is only reserved in the outer wall of the air chamber, the connecting column is used as a connecting foundation of the current transformer and a channel allowing the secondary connecting terminal to penetrate into the low-voltage area, then the plugging cover is used for tightly pressing the first sealing gasket to plug the through hole and the connecting column, and the effect of effectively isolating the space of the high-voltage area and the low-voltage area of the gas-insulated switchgear is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of current transformer structures, and in particular to a self-sealing current transformer for gas-insulated switchgear (GIS). Background Art

[0002] In the manufacturing field of distribution switch control equipment such as distribution systems and facilities, GIS, as a key power equipment, is widely used in medium and high voltage 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 combination with GIS due to their excellent electrical properties, heat resistance, and mechanical strength.

[0003] A GIS usually includes electronic components such as circuit breakers, contactors, thermal relays, and current transformers. The current transformer is used to convert large currents into small currents for subsequent measurement, protection, and control. See Figure 1 , a common current transformer consists of a magnetic core, a primary coil 11 wound around the magnetic core, and a secondary coil 12. The primary coil 11 is used to connect to the input end, and the secondary coil 12 is used to connect to the output end. Then, the magnetic core, primary coil 11, and secondary coil 12 are insulated and cast, and after being packaged with an insulating housing 101, the housing 101 of the current transformer is installed on the inner wall of the gas chamber of the GIS 102 through bolts. The connection terminal of the secondary coil 12 also passes through the inner wall of the GIS 102 into the low-voltage area, thereby effectively isolating the high-voltage area and low-voltage area of the GIS 102 using the current transformer.

[0004] However, sulfur hexafluoride gas usually needs to be filled in the high-voltage gas chamber of the GIS. Holes need to be opened on the inner wall of the gas chamber of the GIS for the installation of the current transformer and the connection of the low-voltage area circuit to the connection terminal of the second coil. This will increase the sealing difficulty of the gas chamber of the GIS, and it is also easy for water vapor to penetrate into the current transformer and even the gas chamber of the GIS from the connection terminal, which is likely to cause corrosion of metal parts and even short circuits in severe cases. 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 invention objective, the technical solution adopted by the present invention is as follows: Provide a self-sealing current transformer for gas-insulated switchgear, including a housing assembly and a current transformer body; The current transformer body includes a primary coil and a secondary coil. The primary coil and the secondary coil are sleeved with each other. The primary coil is connected with a primary connection terminal, and the secondary coil is connected with a secondary connection terminal. The mutual inductor body is arranged inside the housing assembly. The housing assembly includes an upper housing and a lower housing. The upper housing and the lower housing are detachably connected. Two first connection terminals are arranged on the upper housing. The first connection terminals are connected to the primary connection terminals. The lower housing has connection posts. A plugging cover is threadedly connected to one end of the connection post away from the lower housing. The housing assembly is arranged inside the gas chamber of the gas-insulated switchgear. The connection posts pass through the inner wall of the gas chamber and are connected to the plugging cover. A first sealing gasket is arranged between the plugging cover and the outer wall of the gas chamber. A second connection terminal is arranged on the plugging cover. A perforation is coaxially opened inside the connection post. The secondary connection terminal passes through the connection post and is connected to the second connection terminal.

[0007] Furthermore, the upper housing includes an upper inner housing and an upper outer housing. The lower housing includes a lower inner housing and a lower outer housing. The upper inner housing and the lower inner housing are detachably connected by a first connecting member. A second sealing gasket is arranged on the contact surface between the upper inner housing and the lower inner housing. The upper outer housing and the lower outer housing are detachably connected by a second connecting member. A first elastic connecting piece is integrally arranged at the top of the upper inner housing. The primary connection terminal and the first connection terminal are connected by the first elastic connecting piece. The connection post is integrally and fixedly arranged at the bottom of the lower inner housing. The connection post passes through the lower outer housing.

[0008] Furthermore, a third sealing gasket for contacting the inner bottom wall of the lower outer housing is arranged at the edge of the bottom wall of the lower inner housing. A fourth sealing gasket for contacting the inner wall of the gas chamber is arranged at the edge of the bottom wall of the lower outer housing.

[0009] Furthermore, the first connecting member is a first connecting piece. The first connecting piece is integrally and fixedly connected to the lower inner housing. The first connecting piece is symmetrically arranged in the middle of the two long sides on both sides of the lower inner housing. The first connecting piece is used to extend into the upper inner housing. A first ratchet tooth bar is arranged on the surface of the first connecting piece for contacting the inner wall of the upper inner housing. A second ratchet tooth bar adapted to the first ratchet tooth bar is arranged on the inner wall of the upper inner housing. The first ratchet tooth bar and the second ratchet tooth bar cooperate to limit the separation of the lower inner housing and the upper inner housing. The second connecting member is a connecting bolt. Connecting lugs are arranged on the outer walls of the upper outer housing and the lower outer housing. The connecting bolt passes through the lugs on the upper outer housing and the lower outer housing at the same time and is threadedly connected to a nut.

[0010] Furthermore, the second connection terminal is rotatably connected to the plugging cover. A guiding head with a polygonal cross-section is fixedly arranged at one end of the second connection terminal close to the lower inner housing. A guiding groove adapted to the guiding head is opened at one end of the connection post away from the lower inner housing.

[0011] Furthermore, a layer of rubber cushion layer is arranged on the inner wall of the guiding groove.

[0012] Furthermore, a plurality of first guiding pieces are fixedly arranged on the lower inner housing. A plurality of first guiding grooves adapted to the first guiding pieces are vertically opened on the inner wall of the upper inner housing. A number of second guiding pieces are fixedly arranged on the outer wall of the lower inner shell, and a number of second guiding grooves adapted to the second guiding pieces are vertically formed on the inner wall of the lower outer shell.

[0013] Furthermore, an extrusion strip with a width greater than that of the second guiding piece is arranged at one end of the second guiding piece close to the upper inner shell. A guiding surface with an inclined surface is formed between the second guiding piece and the extrusion strip. An elastic strip is fixedly arranged on the upper outer shell. A first extrusion part protrudes from one side of the end of the elastic strip close to the extrusion strip, and a buckle part protrudes from the other side. A limiting part is arranged on the inner wall of the lower outer shell. When the upper outer shell and the lower outer shell are combined, the end of the elastic strip far from the inner bottom wall of the upper outer shell extends into the lower outer shell, and the buckle part is located on the side of the limiting part close to the inner bottom wall of the lower outer shell. The first extrusion part and the extrusion strip cooperate to squeeze so that the buckle part and the limiting part cooperate to limit the separation of the upper outer shell and the lower outer shell.

[0014] Furthermore, the primary coil and the secondary coil are cast into one body by insulating resin.

[0015] Furthermore, insulating foams are arranged on the inner walls of the upper inner shell and the lower inner shell.

[0016] The beneficial effects of the present invention are as follows: 1. The current transformer body is installed in the outer shell assembly. The primary coil of the current transformer body is connected to the two first connection terminals of the upper shell. The connection column on the lower shell passes through the side wall of the gas chamber of the gas-filled cabinet and is threadedly connected to the sealing cover. The secondary connection terminal on the secondary coil of the current transformer body is connected to the second connection terminal on the sealing cover after passing through the through hole on the connection column. Only a through hole for the connection column to pass through is left on the outer wall of the gas chamber. The connection column is used as the connection support leg between the current transformer and the gas chamber, and the through hole on the connection column is used as the channel for the secondary connection terminal to penetrate into the low-voltage area. When sealing the through hole, the sealing cover tightly presses the first sealing gasket to realize the sealing of the through hole of the gas chamber and the through hole on the connection column, which can reduce the number of openings on the inner wall of the gas-filled cabinet, centrally seal the position where the connection column passes through the gas-filled cabinet, and effectively realize the spatial isolation between the high-voltage area and the low-voltage area of the gas-filled cabinet; 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 moves elastically relative to the outer shell group. The current transformer body is located inside the inner shell group, which can effectively isolate external impacts during the storage and transportation process after the production of the current transformer, and improve the protection effect on the current transformer body; 3. When installing the current transformer, as the sealing cover is tightened, the inner shell group can move relative to the outer shell group, causing the first elastic connecting piece to elongate. The construction personnel can judge whether the inner shell group is in close contact with the inner bottom wall of the outer shell group by the magnitude of the pressure applied by tightening the sealing cover. When the inner shell group completely abuts against the inner bottom wall of the lower outer shell, that is, the lower outer shell and the sealing cover have jointly clamped the inner wall of the gas-filled cabinet tightly. At this time, the force required to screw the sealing cover suddenly increases, which is convenient for the construction personnel to judge that the current transformer is stably installed on the inner wall of the gas-filled cabinet; 4. After ensuring that the inner shell group is moved in place, the elastic force of the first elastic connecting piece can be used to pull the sealing cover to tightly press the first sealing gasket. Even if the sealing cover becomes loose during the use of the gas-insulated switchgear, the elastic force of the first elastic connecting piece can be utilized to maintain the sealing of the hole through which the connecting post on the gas-insulated switchgear passes, and the sealing effect of the high-pressure area chamber of the gas-insulated switchgear can be maintained for a long time. 5. During the process of screwing the sealing cover to fix the current transformer on the gas-insulated switchgear, the guiding head on the second wiring terminal cooperates with the guiding groove on the connecting post, so that the second wiring terminal can keep the connecting post blocked in an axial movement manner, avoiding the secondary wiring terminal from rotating and winding around with the sealing cover. Moreover, the guiding head cooperates with the rubber cushion layer on the inner wall of the guiding groove, which can effectively seal the perforation of the connecting post. 6. After combining the upper outer shell and the lower outer shell and fixing the current transformer in the gas chamber, the extrusion strip on the outer wall of the inner shell group is in extrusion contact with the first extrusion part of the outer shell group, pushing the buckle part to cooperate with the limiting part, so that when the current transformer is installed in the gas chamber, the upper outer shell and the lower outer shell cannot be separated, avoiding safety problems 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-insulated switchgear, under the elastic force of the first elastic connecting piece, the inner shell group is pulled into the upper outer shell, so that the extrusion strip releases the extrusion on the first extrusion part, the elastic strip resets, and the buckle part and the limiting part are disengaged from the cooperation relationship. Only at this time can the upper outer shell and the lower outer shell be disassembled, improving the operation safety of the current transformer. Description of the Drawings

[0017] Figure 1 It is a schematic diagram of the installation of the current transformer in the prior art.

[0018] Figure 2 It is a schematic diagram of the overall structure of the current transformer according to the embodiment of the present application.

[0019] Figure 3 It is a schematic diagram of the internal sectional structure of the current transformer according to the embodiment of the present application.

[0020] Figure 4 It is Figure 3 A partial enlarged schematic diagram of part A in

[0021] Figure 5 It is a schematic diagram of the internal sectional structure of the current transformer from another perspective according to the embodiment of the present application.

[0022] Figure 6 It is Figure 5 A partial enlarged schematic diagram of part B in

[0023] Figure 7 It is an exploded schematic diagram of the upper shell of the embodiment of the present application.

[0024] Figure 8 Explosion schematic diagram of the lower housing of the embodiment of the present application.

[0025] Figure 9 Schematic diagram of the connection state between the upper housing and the lower housing when the current transformer of the embodiment of the present application is installed in the gas chamber.

[0026] Wherein, 1. Transformer body; 11. Primary coil; 111. Primary wiring terminal; 12. Secondary coil; 121. Secondary wiring terminal; 2. Upper housing; 21. First wiring head; 22. Upper inner housing; 221. Second ratchet rack; 222. First guide groove; 23. Upper outer housing; 231. Elastic strip; 232. First extrusion part; 233. Buckle part; 24. First elastic connection piece; 3. Lower housing; 31. Lower inner housing; 311. First connection piece; 312. First ratchet rack; 313. First guide piece; 314. Second guide piece; 315. Extrusion strip; 316. Guide surface; 32. Lower outer housing; 321. Second guide groove; 322. Limiting part; 33. Third gasket; 34. Fourth gasket; 41. Connecting column; 411. Perforation; 412. Guide groove; 42. Sealing cover; 421. Guide head; 43. First gasket; 44. Second wiring head; 5. Second gasket; 61. Connecting ear piece; 62. Connecting bolt; 7. Insulating foam; 101. Housing; 102. Gas-insulated switchgear. Detailed implementation manners

[0027] In order to better understand the above technical solution, the above technical solution will be described in detail below in conjunction with the accompanying drawings of the specification and specific implementation manners.

[0028] The embodiment of the present application discloses a self-sealing current transformer for a gas-insulated switchgear. Referring to Figure 2 , Figure 3 , Figure 4 and Figure 5 , it includes a housing assembly and a transformer body 1. The transformer body 1 includes a primary coil 11 and a secondary coil 12. Specifically, the primary coil 11 is made of a high-conductivity strip-shaped flat copper wire and is used to access the high-voltage circuit to reduce the resistance heating of the primary coil 11. The secondary coil 12 is composed of a copper wire wound around a magnetic core. The secondary coil 12 is used to access the low-voltage circuit. The primary coil 11 and the secondary coil 12 are sleeved with each other and are integrally formed by vertical insulation casting. The insulating resin is specifically epoxy resin to keep the primary coil 11 and the secondary coil 12 insulated from each other and to isolate air and water vapor. The transformer body 1 further includes two primary wiring terminals 111 and two secondary wiring terminals 121. The two primary wiring terminals 111 are respectively connected to both ends of the primary coil 11, and the two secondary wiring terminals 121 are respectively connected to both ends of the secondary coil 12.

[0029] Referring to Figure 5 andFigure 6 , 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, and the upper housing 2 and the lower housing 3 together form a receiving cavity capable of receiving the current transformer body 1. Two first connection terminals 21 are provided on the upper housing 2, and the two first connection terminals 21 are respectively connected to the two primary connection terminals 111. The lower housing 3 is provided with a connection post 41, the connection post 41 is provided with an external thread, and a plugging cover 42 is threadedly connected to one end of the connection post 41 away from the lower housing 3. A through hole 411 is formed through the connection post 41, and a second connection terminal 44 is provided on the plugging cover 42. The secondary connection terminal passes through the connection post 41 and is connected to the second connection terminal 44. When the current transformer is used and installed, the housing assembly and the current transformer body 1 are placed in the gas chamber of the gas-insulated switchgear 101. After the connection post 41 passes through the inner wall of the gas chamber, it is then threadedly connected to the plugging cover 42. A first sealing gasket 43 is sleeved outside the connection post 41, and the plugging cover 42 abuts against the outer wall of the gas chamber of the gas-insulated switchgear 101 through the first sealing gasket 43.

[0030] The first sealing gasket 43 is an insulating rubber sealing gasket. During the installation process of the current transformer in this application, only through holes for the two connection posts 41 to pass through are required on the gas chamber. By closing the through hole 411 on the connection post 41 with the plugging cover 42, the interior of the current transformer can be ensured to be sealed. Then, by the first sealing gasket 43 being located on the outside of the through hole between the plugging cover 42 and the outer wall of the gas chamber, the gap between the through hole and the connection post 41 can be sealed, thereby maintaining the sealing effect on the gas chamber. Furthermore, by using the epoxy resin casting method to wrap the primary coil 11 and the secondary coil 12 into one body, the insulation distance between the primary coil 11 and the secondary coil 12 can be effectively maintained, and dust and water can be effectively prevented, maintaining its high precision.

[0031] Referring to Figure 7 and Figure 8 , further, the upper housing 2 can be composed of an upper inner housing 22 and an upper outer housing 23, and the lower housing 3 can be composed of 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 connecting member, and 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 connecting member.

[0032] At the top of the upper inner shell 22, there are two first elastic connection pieces 24. The primary wiring terminal 111 and the first wiring head 21 are connected through the first elastic connection pieces 24. The first elastic connection pieces 24 are in an inclined Z shape, so that both ends of the first elastic piece have elastic movement margins. The connecting column 41 is integrally fixed at the bottom of the lower inner shell 31, and the connecting column 41 passes through the lower outer shell 32. Specifically, both ends of the first elastic connection piece 24 can be fused and embedded in the tops of the upper inner shell 22 and the upper outer shell 23. During use, after the connecting column 41 passes through the lower outer shell 32 and the side wall of the air chamber, it is connected to the sealing cover 42. During the connection process, the sealing cover 42 abuts against the outer wall of the air chamber, pulling the entire lower inner shell 31 and the upper inner shell 22 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. Through the double-layer outer shell assembly, the anti-puncture protection effect on the transformer body 1 can be improved, and the dust-proof and waterproof effects on the transformer body 1 during daily use can also be improved.

[0033] Further, a first annular groove is formed at 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 at 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. Through the second sealing gasket 5, when the upper inner shell 22 and the lower inner shell 31 are connected, the second sealing gasket 5 seals the joint between the upper inner shell 22 and the lower inner shell 31, keeping the environment between the upper inner shell 22 and the lower inner shell 31 closed. When the lower inner shell 31 is forced to move and press against the inner bottom wall of the lower outer shell 32, 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 outer shell 32 contacts the inner wall of the air chamber, the fourth sealing gasket 34 can seal the gap between the lower outer shell 32 and the inner wall of the air chamber. The third sealing gasket 33 and the fourth sealing gasket 34 are used in combination to completely block the through hole opened in the air chamber, completely isolating the air chamber of the gas-filled cabinet 101 from the low-voltage part.

[0034] In the embodiment of the present application, the first connecting member is the first connecting piece 311. The first connecting piece 311 is integrally and fixedly connected to the lower inner shell 31. The first connecting piece 311 is symmetrically arranged in the middle of the two long 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 rack 312 is arranged on the surface of the first connecting piece 311 for contacting the inner wall of the upper inner shell 22. A second ratchet rack 221 adapted to the first ratchet rack 312 is arranged on the inner wall of the upper inner shell 22. The first ratchet rack 312 and the second ratchet rack 221 cooperate to limit 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 completely connected, the first ratchet rack 312 and the second ratchet rack 221 are completely engaged. And the gap between the lower inner shell 31 and the upper inner shell 22 under this engagement should be less than the width of the second sealing gasket 5 in the relaxed state, so that after the lower inner shell 31 and the upper inner shell 22 are completely combined, the second sealing gasket 5 is kept squeezed, improving the sealing effect of the second sealing gasket 5 on the gap between the two. The first connecting piece 311 is arranged in the middle of the long side of the lower inner shell 31 for the purpose that when it is necessary to disassemble the upper inner shell 22 and the lower inner shell 31, by squeezing from the middle of the two long sides of the lower inner shell 31, the two sides of the lower inner shell 31 are deformed at the position of the first connecting piece 311, so that the first ratchet rack 312 and the second ratchet rack 221 are disengaged, and the lower inner shell 31 can be normally separated from the upper inner shell 22. In the embodiment of the present application, the first connecting piece 311 needs to be arranged on the lower inner shell 31. In the normal state, the upper inner shell 22 is elastically pulled by the first elastic connecting piece 24 and retracted into the upper outer shell 23, which is not convenient for operating the upper inner shell 22, and only the lower inner shell 31 has an operable space.

[0035] The second connecting member can be the connecting bolt 62. Connecting lugs 61 are integrally and fixedly arranged on the outer walls of the upper outer shell 23 and the lower outer shell 32. The connecting bolt 62 passes through the connecting lugs 61 on the upper outer shell 23 and the lower outer shell 32 at the same time and is threadedly connected to the nut.

[0036] Further, in order to avoid torsional damage to the secondary terminal 121 during the rotation and threaded connection between the plugging cover 42 and the connecting column 41, in the embodiment of the present application, the second terminal 44 is rotatably connected to the plugging cover 42. Specifically, a guiding head 421 with a polygonal cross-section is integrally fixed at one end of the second terminal 44 close to the inner shell, and a guiding groove 412 adapted to the guiding head 421 is provided at one end of the connecting column 41 away from the lower inner shell 31. The guiding head 421 can be made of rubber material, providing an elastic movement margin for the movement of the plugging cover 42 on the connecting column 41, ensuring that the plugging cover 42 can cooperate with the lower outer shell 32 to clamp the inner wall of the gas-filled cabinet 101. Also, first gaskets 43 with different thicknesses can be selected according to the different thicknesses of the inner wall of the gas-filled cabinet 101, ensuring that the perforation 411 on the connecting column 41 can be plugged while the lower outer shell 32 and the plugging cover 42 clamp and fix the inner wall of the gas-filled cabinet 101. When connecting the plugging cover 42 to the connecting column 41, insert the guiding head 421 into the guiding groove 412 on the connecting column 41 in alignment. When the plugging cover 42 is rotationally fixed on the connecting column 41, under the limitation of the guiding groove 412, the guiding head 421 can maintain axial movement with the connecting column 41, avoiding rotation and entanglement of the secondary terminal 121.

[0037] In order to continuously maintain the sealing effect of the plugging cover 42 on the perforation 411 on the connecting column 41, in the embodiment of the present application, a layer of rubber cushion layer is provided on the inner wall of the guiding groove 412, and the guiding head 421 can be set as a frustum with a taper of 3° - 6°. As the guiding head 421 continues to move into the connecting column 41, the guiding head 421 can fit and squeeze the rubber cushion layer, ensuring the sealing effect on the perforation 411 on the connecting column 41.

[0038] Further, a plurality of first guiding pieces 313 are fixed on the lower inner shell 31, and a plurality of first guiding grooves 412 adapted to the first guiding pieces 313 are vertically provided 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 guiding pieces 313 and the first guiding grooves 412 cooperate with each other, which can avoid misalignment between the upper inner shell 22 and the lower inner shell 31, and can effectively maintain the shape structure of the upper inner shell 22 during the merging and squeezing process of the upper inner shell 22 and the lower inner shell 31. A plurality of second guiding pieces 314 are integrally fixed on the outer wall of the lower inner shell 31, and a plurality of second guiding grooves 321 adapted to the second guiding pieces 314 are vertically provided on the inner wall of the lower outer shell 32. When the lower inner shell 31 and the lower outer shell 32 are successively connected to the upper inner shell 22 and the upper outer shell 23, through the cooperation of the second guiding pieces 314 and the guiding grooves 412, the gap between the lower inner shell 31 and the lower outer shell 32 can be maintained, playing a role in positioning and stabilizing between the lower inner shell 31 and the upper inner shell 22.

[0039] In order to provide sufficient protection for the current transformer body 1, in the embodiment of the present application, insulating foams 7 are also provided on the inner walls of the upper inner shell 22 and the lower inner shell 31. The insulating foams 7 are adhesively fixed to the outer walls of the upper inner shell 22 and the lower inner shell 31. The insulating foams 7 can be any one of polyimide foam, silicone rubber foam, polybenzimidazole foam, etc., and can play roles such as insulation, positioning, and flame retardancy for the current transformer body 1.

[0040] Referring to Figure 9 , in order 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 guiding piece close to the upper inner shell 22. The width of the extrusion strip 315 is greater than the width of the second guiding piece 314. A guiding surface 316 with an inclined surface is formed between the second guiding piece 314 and the extrusion strip 315. An elastic strip 231 is fixedly arranged on the upper outer shell 23. A first extrusion portion 232 protrudes from one surface of the end of the elastic strip 231 close to the extrusion strip 315, and a buckle portion 233 protrudes from the other surface. A limiting portion 322 is arranged 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 buckle portion 233 is located on the side of the limiting portion 322 close to the inner bottom wall of the lower outer shell 32. When the upper outer shell 23 and the lower outer shell 32 are combined and the current transformer is installed on the inner wall of the gas chamber, the upper inner shell 22 and the lower inner shell 31 move towards the inner wall of the gas chamber, and the extrusion strip 315 moves to one side of the first extrusion portion 232. The first extrusion portion 232 and the extrusion strip 315 cooperate to squeeze so that the buckle portion 233 and the limiting portion 322 cooperate, thereby restricting the separation of the upper outer shell 23 and the lower outer shell 32. Before the current transformer can be effectively disassembled from the gas chamber, the connection and fixation relationship between the upper outer shell 23 and the lower outer shell 32 can be maintained, avoiding opening the upper outer shell 23 and the lower outer shell 32 before the safe disassembly of the current transformer and causing various safety accidents.

[0041] During the production process of the current transformer, the first elastic connecting piece 24 is first welded to the primary wiring terminal 111 of the transformer body 1. Then, the top end of the first elastic connecting piece 24 is passed through the upper housing 23 and bent to form the first connection head 21. The gap between the first elastic connecting piece 24 and the upper housing 23 is sealed and fixed to the first elastic connecting piece 24 by melting the upper housing 23 or additionally supplementing sealant. Under the elastic force of the first elastic connecting piece 24, the upper inner shell 22 and the transformer body 1 are pulled and received into the lower housing 32. Then, the lower inner shell 31 is installed, so that the secondary wiring terminal 121 of the second coil passes through the connecting column 41. Then, the lower housing 32 is installed, so that the connecting column 41 passes through the lower housing 32. When installing the current transformer, the connecting column 41 is passed through the inner wall of the gas-filled cabinet 102, and the secondary wiring terminal 121 and the second connection head 44 are connected by welding and detachable connection methods. During the process of screwing the plugging cover 42 onto the connecting column 41, the guiding head 421 cooperates with the guiding groove 412 to plug the connecting column 41 and install the connecting column 41 on the gas-filled cabinet 102 while preventing the secondary wiring terminal 121 from rotating and winding. The secondary wiring terminal 121 is compressed in the through hole 411 of the connecting column 41.

[0042] Those skilled in the art should understand that although the preferred embodiments of the present invention have been described, once the basic creative concepts are known to those skilled in the art, additional changes and modifications can be made to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of the present invention. Obviously, those skilled in the art can make various changes and variations to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalent technologies, the present invention is also intended to include these modifications and variations.

Claims

1. A self-sealing current transformer for an inflatable cabinet, characterized in that: It comprises a housing assembly and a transformer body (1); The transformer body (1) comprises a primary coil (11) and a secondary coil (12), wherein the primary coil (11) and the secondary coil (12) are mutually sleeved, the primary coil (11) is connected to a primary wiring terminal (111), and the secondary coil (12) is connected to a secondary wiring terminal (121); The transformer body (1) is arranged inside a housing assembly, the housing assembly comprising an upper housing (2) and a lower housing (3), the upper housing (2) and the lower housing (3) being detachably connected, two first wiring heads (21) being arranged on the upper housing (2), the first wiring heads (21) being connected to a primary wiring terminal (111), a connecting column (41) being arranged at the bottom of the lower housing (3), and a sealing cover (42) being threadedly connected to one end of the connecting column (41) away from the lower housing (3); The housing assembly is arranged in the air chamber of the inflatable cabinet (101); the connecting column (41) passes through the inner wall of the air chamber and is connected to the blocking cover (42); a first sealing gasket (43) is arranged between the blocking cover (42) and the outer wall of the air chamber; a second terminal (44) is arranged on the blocking cover (42); a through hole (411) is coaxially opened in the connecting column (41); and the secondary connecting terminal passes through the connecting column (41) and is connected to the second terminal (44).

2. The self-sealing current transformer for an inflatable cabinet according to claim 1, characterized in that: The upper shell (2) comprises an upper inner shell (22) and an upper outer shell (23); the lower shell (3) comprises 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 via a first connecting member; a second sealing gasket (5) is provided on the contact surface between the upper inner shell (22) and the lower inner shell (31); and the upper outer shell (23) and the lower outer shell (32) are detachably connected via a second connecting member; A first elastic connecting piece (24) is integrally provided on the top of the upper inner shell (22), the primary wiring terminal (111) and the first wiring head (21) are connected via the first elastic connecting piece (24), the connecting column (41) is integrally fixedly provided on the bottom of the lower inner shell (31), and the connecting column (41) passes through the lower outer shell (32).

3. The self-sealing current transformer for an inflatable cabinet according to claim 2, 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.

4. The self-sealing current transformer for an inflatable cabinet according to claim 2, characterized in that: The first connecting member 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 at 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 bar (312) is arranged on a side of the first connecting piece (311) used to contact the inner wall of the upper inner shell (22), a second ratchet bar (221) adapted to the first ratchet bar (312) is arranged on the inner wall of the upper inner shell (22), the first ratchet bar (312) and the second ratchet bar (221) cooperate to limit the lower inner shell (31) from separating from the upper inner shell (22); The second connecting member is a connecting bolt (62), and connecting ears (61) are provided on the outer walls of the upper shell (23) and the lower shell (32). The connecting bolt (62) passes through the connecting ears (61) on the upper shell (23) and the lower shell (32) at the same time and is threadedly connected with a nut.

5. The self-sealing current transformer for an inflatable cabinet according to claim 4, characterized in that: The second terminal head (44) is rotatably connected to the blocking cover (42); a guide head (421) having a polygonal cross section is fixedly provided at one end of the second terminal head (44) close to the lower inner shell (31); and a guide groove (412) adapted to the guide head (421) is provided at one end of the connecting column (41) away from the lower inner shell (31).

6. The self-sealing current transformer for an inflatable cabinet according to claim 5, characterized in that: A rubber cushion layer is provided on the inner wall of the guide groove (412).

7. The self-sealing current transformer for an inflatable cabinet according to claim 2, characterized in that: A plurality of first guide pieces (313) are fixedly arranged on the lower inner shell (31), and a plurality of first guide grooves (222) adapted to the first guide pieces (313) are vertically opened on the inner wall of the upper inner shell (22); A plurality of second guide pieces (314) are fixedly arranged on the outer wall of the lower inner shell (31), and a plurality of second guide grooves (321) adapted to the second guide pieces (314) are vertically provided on the inner wall of the lower outer shell (32).

8. The self-sealed current transformer for an inflatable cabinet according to claim 7, characterized in that: An extrusion strip (315) having a width greater than that of the second guide strip (314) is disposed at one end of the second guide strip (314) close to the upper inner shell (22); an inclined guide surface (316) is formed between the second guide strip (314) and the extrusion strip (315); an elastic strip (231) is fixedly disposed on the upper outer shell (23); a first extrusion portion (232) is protrudingly disposed on one side of the end of the elastic strip (231) close to the extrusion strip (315), and a buckle portion (233) is protrudingly disposed on the other side; A limiting portion (322) is provided on the inner wall of the lower shell (32); when the upper shell (23) and the lower shell (32) are combined, one end of the elastic strip (231) away from the inner bottom wall of the upper shell (23) extends into the lower shell (32); and the buckle portion (233) is located on a side of the limiting portion (322) close to the inner bottom wall of the lower shell (32); the first extrusion portion (232) and the extrusion strip (315) cooperate to extrude so that the buckle portion (233) and the limiting portion (322) cooperate to limit the separation of the upper shell (23) and the lower shell (32).

9. The self-sealed current transformer for an inflatable cabinet according to any one of claims 2 to 8, characterized in that: The primary coil (11) and the secondary coil (12) are cast into one piece by insulating resin.

10. The self-sealed current transformer for an inflatable cabinet according to claim 9, characterized in that: Insulating foam (7) is provided on the inner walls of the upper inner shell (22) and the lower inner shell (31).

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