An external current transformer and GIS

Abstract

The invention relates to an external current transformer and a GIS. The external current transformer comprises: a transformer housing, a bottom support plate of the transformer housing is fixedly assembled with an electrical housing of a switch electrical appliance at the lower side of the GIS; a support cylinder, the support cylinder is used to be coaxially sleeved outside a central conductive rod of the GIS, and the inner circumference and outer circumference of the support cylinder are both cylindrical surfaces; a transformer coil is sleeved outside the support cylinder in a direction toward the bottom support plate; a top butt flange is used to be sealed and fixedly assembled with the electrical housing of the switch electrical appliance at the upper side of the GIS; the top butt flange has a flange center hole, and the top of the support cylinder is sealed and inserted into the flange center hole; during assembly, the inner circumference and outer circumference of the support cylinder are both cylindrical surfaces, which reduces the internal space of the support cylinder and the central conductive rod, reduces the size of the support cylinder, and reduces the inner diameter of the transformer coil sleeved outside the support cylinder, thereby reducing the overall size of the GIS.

Description

Technical Field

[0001] The invention relates to an external current transformer and a GIS. Background Art

[0002] Current transformers for GIS are divided into external and internal types. The external type means that the current transformer coil is placed outside the sulfur hexafluoride insulating gas of the GIS equipment; while the internal type is placed inside the sulfur hexafluoride insulating gas.

[0003] Due to factors such as the difficulty in controlling the water level in built-in current transformers, external current transformers have become a development trend.

[0004] The Chinese invention patent application with application publication number CN111192740A discloses an external current transformer, including: a support cylinder, through which the corresponding central conductive rod in the GIS passes, and a transformer coil is sleeved on the outside of the support cylinder; a connecting cylinder section is provided on the top of the support cylinder, and the connecting cylinder section is used to be fixedly assembled with the housing of the upper switch electrical appliance through an external flange.

[0005] Considering that a set insulation gap must be reserved between the support tube and the central conductive rod in the center, an outward edge is set on the top of the connecting cylinder section to seal with the adapter flange surface, resulting in a larger overall outer diameter of the connecting cylinder section. Since the transformer coil needs to pass through the connecting cylinder section before it can be mounted on the outside of the adapter cylinder section of the support tube, the connecting cylinder section with a larger outer diameter will cause the inner diameter of the transformer coil to be larger. Correspondingly, the outer diameter of the transformer coil will also increase, making the overall size of the GIS larger, which restricts the development trend of compact and miniaturized design of GIS equipment.

[0006] Moreover, in fact, the outer diameter of the adapting cylinder segment is usually basically consistent with the outer diameter of the outward turn edge of the connecting cylinder segment. However, considering the cost issue, the thickness of the adapting cylinder segment will not be very large, which causes the inner diameter of the adapting cylinder segment to be larger than the inner diameter of the connecting cylinder segment, and there is a waste of space between the adapting cylinder segment and the center conductive rod. Summary of the invention

[0007] The object of the present invention is to provide an external current transformer to solve the technical problem in the prior art that the outer edge of the top of the support tube is connected to the upper disconnector electrical housing through a transition flange, resulting in a larger inner diameter of the transformer coil; at the same time, the present invention also provides a GIS using the above-mentioned external current transformer to solve the technical problem in the prior art that the GIS size is larger due to the larger size of the current transformer.

[0008] To achieve the above object, the technical solution of the external current transformer provided by the present invention is: an external current transformer, comprising:

[0009] The transformer housing includes a bottom support plate and a support cylinder that are fixedly assembled together, wherein the bottom support plate is used for sealing and fixing with the electrical housing of the switch electrical appliance at the lower side of the GIS, and the support cylinder is used for coaxially sleeved outside the central conductive rod of the GIS;

[0010] A mutual inductor coil is sleeved outside the support tube in a direction toward the bottom support plate;

[0011] The inner circumferential surface and the outer circumferential surface of the support tube are both cylindrical surfaces;

[0012] The external current transformer also includes a top docking flange, which is used for sealing and fixing with the electrical housing of the upper switch electrical appliance of the GIS;

[0013] The top docking flange has a flange center hole, and the top seal of the support tube is inserted into the flange center hole;

[0014] The top docking flange is fixedly assembled relative to the bottom support plate through an outer support structure, and the outer support structure is located outside the mutual inductor coil;

[0015] The outer supporting structure includes a plurality of supporting screws arranged in sequence around the transformer coil, the lower portion of the supporting screws is fixedly assembled with the bottom supporting plate, and the upper portion is detachably fixedly assembled with the top docking flange; the external current transformer also includes an outer protective cover, which is arranged outside the outer supporting structure.

[0016] The beneficial effects are as follows: in the external current transformer provided by the present invention, the bottom support plate of the transformer housing is fixedly assembled with the electrical housing of the switch electrical appliance at the lower side of the GIS; the transformer coil is mounted on the outer cylindrical surface of the support tube; the central conductive rod is coaxially assembled with the support tube, which is convenient for assembly; the inner and outer peripheral surfaces of the support tube are both cylindrical surfaces, which reduces the space between the support tube and the central conductive rod; the top seal of the support tube is inserted into the center hole of the flange, so that the support tube and the center hole of the flange are sealed and assembled; the outer support structure is fixedly assembled with the bottom support plate outside the transformer coil, and is used to support and connect the bottom support plate and the top docking flange. During assembly, since the top docking flange is fixedly assembled with the transformer housing through the outer support structure, the support tube only needs to be sealed and plugged with the top docking flange, so that the inner and outer peripheral surfaces of the support tube are both cylindrical surfaces. Under the condition of ensuring effective internal insulation, the radial size of the outer peripheral surface of the support tube is relatively small, so that the radial size of the transformer coil is also reduced, and then the radial size of the entire transformer can be effectively reduced. When it is applied to GIS, the size of the GIS will not increase due to the transformer. In addition, since the inner circumference of the support tube is a cylindrical surface, the internal space will not be wasted. The outer support structure uses support screws to support and connect the bottom support plate and the top docking flange, which is convenient for the relative fixed assembly of the top docking flange and the bottom support plate, and is convenient for supporting and reinforcing the overall structure.

[0017] As a further improvement, a circumferential sealing ring is arranged between the outer circumferential surface of the support tube and the inner hole wall of the flange center hole to achieve sealed insertion of the support tube and the flange center hole.

[0018] The beneficial effect is that the outer peripheral surface of the support tube and the center hole of the flange are sealed by a peripheral sealing ring, which simplifies the sealing structure while achieving effective sealing.

[0019] As a further improvement, a sealing ring installation groove is provided on the inner hole wall of the flange center hole, and the peripheral sealing ring is correspondingly installed in the sealing ring installation groove and is sealed with the outer peripheral surface of the support tube.

[0020] The beneficial effect is that the peripheral sealing ring is correspondingly installed in the sealing ring installation groove of the inner hole wall of the flange center hole, so that the sealing ring is easy to install.

[0021] As a further improvement, a limit stop edge is provided at the upper end opening of the flange center hole, and the limit stop edge is located above the support tube and is used to cooperate with the top surface of the support tube to prevent the support tube from passing through the flange center hole upward.

[0022] The beneficial effect is that the top surface of the support tube cooperates with the limit stopper set at the upper end opening of the flange center hole. During installation, the flange center hole can be directly inserted and matched with the top surface of the support tube to effectively limit the support tube.

[0023] As a further improvement, a central flange extending toward the support tube is provided in the middle of the top docking flange, and a through hole is provided at the center of the central flange, and the through hole forms the flange central hole.

[0024] The beneficial effect is that a flange center hole is arranged at the center of the center flange of the top docking flange, so that the sealing and assembly process of the support tube and the top docking flange is simple.

[0025] As a further improvement, an upper connection structure is provided on the upper portion of the outer protective cover for fixed connection with the electrical housing of the upper switch electrical appliance of the GIS, and the lower portion of the outer protective cover is sealingly sleeved outside the bottom support plate.

[0026] The beneficial effect is that the outer protective cover is fixedly connected to the upper switch electrical appliance housing and the bottom support plate, which can effectively protect the mutual inductor.

[0027] The technical solution of GIS provided by the present invention is: a GIS, comprising:

[0028] An upper switch electrical device, an external current transformer and a lower switch electrical device are arranged in sequence, and the switch electrical devices on both sides respectively have electrical device housings;

[0029] A central conductive rod is installed in the center of the external current transformer, and the central conductive rod is electrically connected with the upper switch electrical device and the lower switch electrical device;

[0030] The external current transformer comprises:

[0031] The transformer housing comprises a bottom support plate and a support cylinder which are fixedly assembled together, wherein the bottom support plate is sealed and fixedly assembled with the electrical housing of the lower switch electrical appliance, and the support cylinder is coaxially sleeved outside the central conductive rod;

[0032] A mutual inductor coil is sleeved outside the support tube in a direction toward the bottom support plate;

[0033] The inner circumferential surface and the outer circumferential surface of the support tube are both cylindrical surfaces;

[0034] The external current transformer also includes a top docking flange, which is sealed and fixedly assembled with the electrical housing of the upper switch electrical appliance;

[0035] The top docking flange has a flange center hole, and the top seal of the support tube is inserted into the flange center hole;

[0036] The top docking flange is fixedly assembled relative to the bottom support plate through an outer support structure, and the outer support structure is located outside the mutual inductor coil;

[0037] The outer supporting structure includes a plurality of supporting screws arranged in sequence around the transformer coil, the lower portion of the supporting screws is fixedly assembled with the bottom supporting plate, and the upper portion is detachably fixedly assembled with the top docking flange; the external current transformer also includes an outer protective cover, which is arranged outside the outer supporting structure.

[0038] The beneficial effects are as follows: in a GIS provided by the present invention, the upper switch electrical appliance, the external current transformer and the lower switch electrical appliance are arranged in sequence, and the switch electrical appliances on both sides respectively have electrical appliance shells, which are convenient for docking and fixing with the external current transformer; a central conductive rod is installed in the center of the external current transformer, which is used to connect the upper switch electrical appliance and the lower switch electrical appliance electrically; the bottom support plate of the transformer shell is fixedly assembled with the electrical appliance shell of the lower switch electrical appliance of the GIS; the transformer coil is mounted on the outer cylindrical surface of the support tube; the central conductive rod is coaxially assembled with the support tube, which is convenient for assembly; the inner circumference and outer circumference of the support tube are both cylindrical surfaces, which reduces the space between the support tube and the central conductive rod; the top seal of the support tube is inserted into the center hole of the flange, so that the support tube and the center hole of the flange are sealed and assembled; the outer support structure is fixedly assembled with the bottom support plate outside the transformer coil, which is used to support and connect the bottom support plate and the top docking flange. During assembly, the inner and outer surfaces of the support tube are both cylindrical, which reduces the internal space between the support tube and the central conductive rod, reduces the size of the support tube, and reduces the inner diameter of the transformer coil mounted outside the support tube, thereby achieving the purpose of reducing the overall size of the GIS, making it compact and miniaturized, and saving installation space. The outer support structure uses support screws to support and connect the bottom support plate and the top docking flange, which facilitates the relative fixed assembly of the top docking flange and the bottom support plate, and is convenient for supporting and reinforcing the overall structure.

[0039] As a further improvement, a circumferential sealing ring is arranged between the outer circumferential surface of the support tube and the inner hole wall of the flange center hole to achieve sealed insertion of the support tube and the flange center hole.

[0040] The beneficial effect is that the outer peripheral surface of the support tube and the center hole of the flange are sealed by a peripheral sealing ring, which simplifies the sealing structure while achieving effective sealing.

[0041] As a further improvement, a sealing ring installation groove is provided on the inner hole wall of the flange center hole, and the peripheral sealing ring is correspondingly installed in the sealing ring installation groove and is sealed with the outer peripheral surface of the support tube.

[0042] The beneficial effect is that the peripheral sealing ring is correspondingly installed in the sealing ring installation groove of the inner hole wall of the flange center hole, so that the sealing ring is easy to install.

[0043] As a further improvement, a limit stop edge is provided at the upper end opening of the flange center hole, and the limit stop edge is located above the support tube and is used to cooperate with the top surface of the support tube to prevent the support tube from passing through the flange center hole upward.

[0044] The beneficial effect is that the top surface of the support tube cooperates with the limit stopper provided at the upper end opening of the flange center hole. During installation, the flange center hole can be directly inserted and matched with the top surface of the support tube to effectively limit the support tube.

[0045] As a further improvement, a central flange extending toward the support tube is provided in the middle of the top docking flange, and a through hole is provided at the center of the central flange, and the through hole forms the flange central hole.

[0046] The beneficial effect is that a flange center hole is arranged at the center of the center flange of the top docking flange, so that the sealing and assembly process of the support tube and the top docking flange is simple.

[0047] As a further improvement, an upper connection structure is provided on the upper portion of the outer protective cover for fixed connection with the electrical housing of the upper switch electrical appliance of the GIS, and the lower portion of the outer protective cover is sealingly sleeved outside the bottom support plate.

[0048] The beneficial effect is that the outer protective cover is fixedly connected to the upper switch electrical appliance housing and the bottom support plate, which can effectively protect the mutual inductor.

[0049] As a further improvement, a pot-type insulator is provided at the lower end of the electrical housing of the upper switching electrical appliance, and the outer fixed edge of the pot-type insulator is clamped between the top docking flange of the external current transformer and the lower end of the electrical housing of the upper switching electrical appliance, and corresponding through bolt mounting holes are provided on the pot-type insulator, the top docking flange and the lower end of the electrical housing of the upper switching electrical appliance, and fastening bolts are passed through the bolt mounting holes to fix the top docking flange, the pot-type insulator and the electrical housing of the upper switching electrical appliance together; moreover, the pot-type insulator and the top docking flange are arranged with insulating intervals, and the bolt mounting holes on the top docking flange are located between the center hole of the flange and the outer supporting structure.

[0050] The beneficial effects are as follows: corresponding through bolt mounting holes are provided at the lower ends of the pot-type insulator, the top butt flange and the electrical housing of the upper switch electrical appliance, and the pot-type insulator, the top butt flange and the electrical housing of the upper switch electrical appliance are fixedly assembled together by tightening the bolts, and the operation is convenient; the pot-type insulator and the top butt flange are arranged with insulation intervals to realize the insulating and sealing assembly of the pot-type insulator and the top butt flange; the bolt mounting holes on the top butt flange are located between the flange center hole and the outer supporting structure, so that the pot-type insulator and the top butt flange are easy to install.

[0051] As a further improvement, an insulating pad is arranged between the pot-type insulator and the top butt flange, and an insulating sleeve is sleeved on the fastening bolt to achieve an insulating spacing between the fastening bolt and the top butt flange.

[0052] The beneficial effect is that an insulating pad is arranged between the pot-type insulator and the top butt flange to achieve sealed assembly between the pot-type insulator and the top butt flange, and the fastening bolts are insulated from the top butt flange through the insulating sleeve, thereby achieving effective insulation and simplifying the sealing structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Figure 1 A partial structural diagram of a GIS using an external current transformer provided by the present invention;

[0054] Figure 2 for Figure 1 The enlarged view of point A in the middle;

[0055] Figure 3 for Figure 1 Schematic diagram of the structure of the middle basin insulator;

[0056] Figure 4 for Figure 1 Structural schematic diagram of the middle top butt flange;

[0057] Figure 5 for Figure 1 Schematic diagram of the assembly structure of the fastening bolts, insulating pads and pot-type insulators;

[0058] Figure 6 for Figure 1 The structural diagram of the transformer housing;

[0059] Figure 7 This is a schematic diagram of the local structure of GIS embodiment 2.

[0060] Description of reference numerals:

[0061] 1. Circuit breaker housing; 2. Transformer housing; 21. Bottom support plate; 22. Support cylinder; 3. Transformer coil; 4. Support screw; 5. Outer protective cover; 6. Top docking flange; 61. Sealing ring installation groove; 62. Limit stop edge; 63. Flange center hole; 64. Bolt installation hole; 7. Insulation pad; 8. Basin insulator; 81. Metal flange part; 82. Insulation material part; 83. Insulator center conductor; 9. Center conductive rod; 10. Disconnector housing; 11. Peripheral sealing ring; 12. Insulation sleeve; 13. Fastening bolts; 14. Crimp rod; 15. Outer support sleeve; 16. Guide bar. DETAILED DESCRIPTION

[0062] In order to make the purpose, technical scheme and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention, that is, the embodiments described are only part of the embodiments of the present invention, rather than all of the embodiments. The components of the embodiments of the present invention described and shown in the drawings herein can be arranged and designed in various different configurations.

[0063] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without making creative work are within the scope of protection of the present invention.

[0064] It should be noted that relational terms such as "first" and "second" are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device that includes a series of elements includes not only those elements, but also other elements that are not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprises a..." do not exclude the process or method that includes the elements.

[0065] In the description of the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected" and "connected" that may appear should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, or it can be the internal communication of two components. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0066] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the term "provided with" that may appear should be understood in a broad sense. For example, the object "provided with" may be a part of the body, or may be arranged separately from the body and connected to the body, and the connection may be a detachable connection or an inseparable connection. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0067] The present invention is further described in detail below in conjunction with embodiments.

[0068] Specific embodiment 1 of the GIS provided by the present invention:

[0069] In this embodiment, compared with the prior art, the external current transformer in the GIS adopts an axial sealing method, eliminates the outward turning edge set on the top of the supporting tube, reduces the size of the transformer shell, and reduces the size of the transformer coil mounted outside the supporting tube, thereby reducing the overall size of the GIS, making the GIS compact and miniaturized, thereby reducing the layout space of the GIS.

[0070] like Figures 1 to 6 As shown, the GIS in this embodiment includes an upper switch electrical appliance, an external current transformer and a lower switch electrical appliance arranged in sequence, and the switch electrical appliances on both sides have electrical appliance housings respectively, wherein the upper switch electrical appliance is specifically a disconnector, and the lower switch electrical appliance is a circuit breaker, the electrical housing of the disconnector is a disconnector housing 10, and the electrical housing of the circuit breaker is a circuit breaker housing 1, the upper part of the external current transformer is fixedly connected to the disconnector housing 10, and the lower part is fixedly connected to the circuit breaker housing 1, and a central conductive rod 9 is installed in the center of the external current transformer, and the central conductive rod 9 connects the circuit breaker and the disconnector electrically.

[0071] The above-mentioned circuit breaker is located at the lower side of the current transformer and is used to control the on and off of the circuit at the lower side of the GIS.

[0072] The circuit breaker housing 1 is fixedly mounted on the bottom of the transformer housing 2. The transformer housing 2 includes a bottom support plate 21 and a support cylinder 22 that are welded and fixed together. The bottom support plate 21 is arranged horizontally and fixedly mounted to the flange edge at the top of the circuit breaker housing 1 by bolts.

[0073] A support tube 22 is fixedly installed on one side of the bottom support plate 21. The support tube 22 is arranged vertically to the bottom support plate 21. The support tube 22 is a columnar structure. The inner and outer circumferences are both cylindrical surfaces. The inner circumference points to the center position to form a tube cavity. A central conductive rod 9 is vertically installed at the center position of the tube cavity. The central conductive rod 9 is coaxially mounted on the support tube 22 and is used to connect the upper and lower switching electrical appliances of the external current transformer electrically.

[0074] The transformer coil 3 is sleeved outside the support tube 22 along the direction toward the bottom support plate 21, and is used for inducing a magnetic field to realize transformer current detection.

[0075] The top sealing insert of the support tube is provided with a top docking flange 6, and a center flange extending toward the support tube 22 is provided in the middle of the top docking flange 6. A through hole is provided in the center of the center flange, and the through hole forms a flange center hole 63 for the top sealing insert set of the support tube 22.

[0076] A sealing ring installation groove 61 is provided on the inner hole wall of the flange center hole 63, which is used to install a circumferential sealing ring 11. The circumferential sealing ring 11 is located between the support tube 22 and the inner hole wall of the flange center hole 63, and is sealed with the outer circumference of the support tube 22, so that the support tube 22 and the flange center hole 63 are sealed and inserted together. Here, more than two sealing ring installation grooves 61 are arranged along the axial direction of the support tube. A rectangular groove or T-slot with an O-ring structure can be used for sealing, or a rectangular groove with a Y-ring structure can be used for sealing.

[0077] A limit stop 62 is provided at the upper end of the flange center hole 63. The limit stop 62 is located above the support tube 22 so that the top surface of the support tube 22 is stopped and matched with the flange center hole 63 to prevent the support tube 22 from passing through the flange center hole 63 upward.

[0078] A plurality of bolt mounting holes 64 are evenly distributed around the flange center hole 63 on the top butt flange 6 , and are used to sequentially mount the top butt flange 6 , the pot-type insulator 8 , and the disconnector housing 10 by fastening bolts 13 .

[0079] The upper switch is specifically an isolating switch, which is used to control the on and off of the GIS circuit.

[0080] A pot-type insulator 8 is installed below the disconnector by means of fastening bolts 13. A metal flange portion 81 is provided at the peripheral edge of the pot-type insulator 8, which is used to be assembled with the top docking flange 6 by means of fastening bolts 13. An insulator center conductor 83 is provided on the pot-type insulator 8 facing away from the metal flange portion 81. The insulator center conductor 83 is conductively fixedly assembled with the center conductive rod 9, and is used to conductively connect the mutual inductor with the disconnector. An insulating material portion 82 is provided between the metal flange portion 81 and the insulator center conductor 83.

[0081] An insulating gasket 7 is provided between the pot-type insulator 8 and the top butt flange 6. The upper surface of the insulating gasket 7 is in press-sealed contact with the pot-type insulator 8, and the lower surface is in press-sealed contact with the top butt flange 6, thereby achieving an insulating gap between the pot-type insulator 8 and the top butt flange 6.

[0082] An insulating sleeve 12 is sleeved on the fastening bolt 13 passing through the bolt mounting hole 64 , and the insulating sleeve 12 is pressed into contact with the bottom surface of the top docking flange 6 to achieve an insulating gap at the contact point between the fastening bolt 13 and the top docking flange 6 .

[0083] The top docking flange 6 is relatively fixedly assembled with the bottom support plate 21 through the outer support structure. The outer support structure is specifically the support screw 4. There are multiple support screws 4 on the outside of the support tube 22 and arranged at intervals around the support tube 22. According to the force analysis and calculation of the overall structure, at least 4 support screws 4 are required to provide support for the entire structure. Multiple support screws 4 are evenly spaced and detachably arranged around the mutual inductor coil 3 and installed on the bottom support plate 21, perpendicular to the bottom support plate 21. The upper part of the support screw 4 passes through the top docking flange 6, and the lower part passes through the bottom support plate 21. By tightening the corresponding fastening nuts, the top docking flange 6 is fastened and assembled with the bottom support plate 21 through the support screws 4, which is convenient for supporting and reinforcing the overall structure.

[0084] An outer protective cover 5 is provided on the outer side of the support screw 4, and an upper connecting structure is provided on the upper part of the outer protective cover 5 for being fixedly connected to the isolating switch housing 10. Specifically, the upper part of the outer protective cover 5 is fixedly connected to the isolating switch housing 10 by screws; the lower part is sealed with the bottom support plate 21, thereby forming a sealed wrapping protection on the peripheral side of the external transformer, and a circumferential sealing ring is provided on the outer peripheral surface of the bottom support plate 21, and the circumferential sealing ring is sealed with the outer protective cover 5.

[0085] During assembly, first fix the transformer housing 1 and the circuit breaker housing 1, then set the transformer coil 3 on the outer circumference of the support tube 2, then install the support screw 4 on the bottom support plate 21, coaxially set the center conductive rod 9 in the support tube 22, and then install the circumferential sealing ring 11 into the sealing ring installation groove 11 on the inner hole wall of the center flange hole 63, the center flange hole 63 is located on the top docking flange 6, and the top docking flange 6, insulating pad 7, basin insulator 8, and insulating sleeve 12 are fixedly assembled with the disconnector housing 10 through fastening bolts 13, and the overall lifting is docked so that the top surface of the support tube 22 and the limit stop 62 of the flange center hole 63 are stopped and matched, and then the support screw 4 is adjusted, and the support screw 4 passes through the top docking flange 6, and the top docking flange 6 is fastened and assembled with the bottom support plate 21 through the support screw 4 by tightening the corresponding fastening nut, and finally the upper part of the outer protective cover 5 is docked with the disconnector housing 10, and the lower part is docked with the bottom support plate 21.

[0086] The external current transformer in this embodiment is different from the flange sealing docking method of other external current transformers. It adopts axial sealing docking and cancels the outward turning edge on the upper part of the support tube. The support tube is a straight cylindrical tube, which reduces the internal space between the support tube and the central conductive rod, reduces the size of the support tube, and reduces the size of the transformer coil mounted outside the support tube. This reduces the overall size of the external current transformer, and then reduces the overall size of the GIS, making it compact and miniaturized, saving installation space.

[0087] Specific embodiment 2 of the GIS provided by the present invention:

[0088] The main difference between it and embodiment 1 is that in embodiment 1, the transformer coil is arranged vertically and directly mounted on the outer peripheral surface of the support tube, the support screw supports and connects the top docking flange and the bottom support plate, and the bottom support plate and the outer protective cover are sealed by the peripheral sealing ring. Figure 7 As shown, a crimping rod 14 is radially extended in the middle of the support screw rod 4, and the end of the crimping rod 14 facing away from the support tube 22 is a nut sleeve, and the upper and lower sides of the nut sleeve are provided with fastening nuts that are in tight contact with the nut sleeve and limit the crimping rod 14; the side pointing to the support tube 22 is a radial cylindrical rod. When the GIS is arranged horizontally, the transformer is arranged horizontally, and the crimping rod 14 can be used to press the transformer coil.

[0089] In GIS equipment, reliable conductive connection between the shells is required so that the generated induced current can be grounded. In order to achieve sealing protection, a peripheral sealing ring is set between the outer protective cover and the bottom support plate. The peripheral sealing ring easily affects the reliable connection between the outer protective cover and the bottom support plate, resulting in the problem of "virtual connection". For this reason, in this embodiment, a guide bar 16 is installed between the outer protective cover 5 and the bottom support plate 21, and the two ends of the guide bar are conductively fixedly connected to the bottom support plate 21 and the outer protective cover 5 in a one-to-one correspondence, and can be fixed by bolts. Since the top of the outer protective cover 5 is directly conductively fixed to the disconnector housing 10, and the bottom of the outer protective cover 5 is conductively connected to the bottom support plate 21 through the guide bar 16, the induced current on the disconnector housing 10 will flow to the bottom support plate 21 through the external outer protective cover 5 to achieve grounding. Moreover, this way of conducting current through the outer protective cover 5 can effectively avoid the current from flowing through the support tube 22 of the current transformer to generate induced current, and will not affect the current transformer measurement. This is also the significance of setting effective insulation at the top docking flange 6.

[0090] Specific embodiment 3 of the GIS provided by the present invention:

[0091] The main difference between this embodiment and the first embodiment is that in the first embodiment, the center hole of the flange of the top docking flange is plugged and assembled with the support tube through the peripheral sealing ring. In this embodiment, an end face sealing ring can be provided on the inner end face of the limit stop edge of the center hole of the flange, and the top surface of the support tube is pressed and matched with the end face sealing ring to achieve end face sealing.

[0092] Specific embodiment 4 of the GIS provided by the present invention:

[0093] The main difference between this embodiment and the first embodiment is that in the first embodiment, a limit stop edge is provided at the upper opening of the center hole of the flange to facilitate positioning and assembly. In this embodiment, the center hole of the flange is a cylindrical hole and no limit stop edge is provided.

[0094] Specific embodiment 5 of the GIS provided by the present invention:

[0095] The main difference between this embodiment and Example 1 is that in Example 1, a center flange is provided in the middle of the top docking flange, and the overall strength is relatively high, so that the strength after the flange center hole is provided still meets the requirements, and the thickness of the top docking flange does not need to be designed to be too thick. In this embodiment, the center flange is omitted, and at this time, the thickness of the entire top docking flange can be designed to be relatively thick to meet the strength requirements.

[0096] The present invention also provides a specific embodiment of an external current transformer:

[0097] The structure of the external current transformer in this embodiment is the same as the structure of the external current transformer in the above GIS embodiment 1, and will not be repeated here.

[0098] Of course, in other embodiments, the external current transformer may also adopt the structure of the external current transformer in any one of GIS embodiments 2 to 5, which will not be described in detail here.

[0099] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions recorded in the aforementioned embodiments without creative work, or replace some of the technical features therein with equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present invention shall be included in the protection scope of the present invention.

Claims

1. An external current transformer, comprising: The transformer housing includes a bottom support plate and a support cylinder that are fixedly assembled together, wherein the bottom support plate is used for sealing and fixing with the electrical housing of the switch electrical appliance at the lower side of the GIS, and the support cylinder is used for coaxially sleeved outside the central conductive rod of the GIS; A mutual inductor coil is sleeved outside the support tube in a direction toward the bottom support plate; Characterized in that the inner circumference and the outer circumference of the support tube are both cylindrical surfaces; The external current transformer also includes a top docking flange, which is used for sealing and fixing with the electrical housing of the upper switch electrical appliance of the GIS; The top docking flange has a flange center hole, and the top seal of the support tube is inserted into the flange center hole; The top docking flange is fixedly assembled relative to the bottom support plate through an outer support structure, and the outer support structure is located outside the mutual inductor coil; The outer supporting structure includes a plurality of supporting screws arranged in sequence around the transformer coil, the lower portion of the supporting screws is fixedly assembled with the bottom supporting plate, and the upper portion is detachably fixedly assembled with the top docking flange; the external current transformer also includes an outer protective cover, which is arranged outside the outer supporting structure.

2. The external current transformer according to claim 1, characterized in that: A circumferential sealing ring is arranged between the outer circumferential surface of the support tube and the inner hole wall of the flange center hole to achieve sealed insertion of the support tube and the flange center hole.

3. The external current transformer according to claim 2, characterized in that: A sealing ring installation groove is provided on the inner hole wall of the flange center hole, and the peripheral sealing ring is correspondingly installed in the sealing ring installation groove and is sealed and matched with the outer peripheral surface of the support tube.

4. The external current transformer according to claim 1, characterized in that: A limit stop edge is arranged at the upper end opening of the center hole of the flange, and the limit stop edge is located above the support tube and is used to cooperate with the top surface of the support tube to prevent the support tube from passing through the center hole of the flange upward.

5. The external current transformer according to claim 4, characterized in that: A central flange extending toward the support tube is provided in the middle of the top docking flange, and a through hole is provided at the center of the central flange, which forms the flange central hole.

6. The external current transformer according to any one of claims 1 to 5, characterized in that: An upper connection structure is provided on the upper part of the outer protective cover for fixedly connecting with the electrical housing of the upper switch electrical appliance of the GIS, and a lower part of the outer protective cover is sealed and sleeved outside the bottom support plate.

7. A GIS comprising: An upper switch electrical device, an external current transformer and a lower switch electrical device are arranged in sequence, and the switch electrical devices on both sides respectively have electrical device housings; A central conductive rod is installed in the center of the external current transformer, and the central conductive rod is electrically connected with the upper switch electrical device and the lower switch electrical device; It is characterized in that the external current transformer adopts the external current transformer described in any one of claims 1 to 6.

8. The GIS according to claim 7, characterized in that: A pot-type insulator is arranged at the lower end of the electrical housing of the upper switch electrical appliance, and the outer fixed edge of the pot-type insulator is clamped between the top docking flange of the external current transformer and the lower end of the electrical housing of the upper switch electrical appliance, and corresponding through bolt mounting holes are arranged on the pot-type insulator, the top docking flange and the lower end of the electrical housing of the upper switch electrical appliance, and fastening bolts are passed through the bolt mounting holes to fix the top docking flange, the pot-type insulator and the electrical housing of the upper switch electrical appliance together; and the pot-type insulator and the top docking flange are arranged with insulating intervals, and the bolt mounting holes on the top docking flange are located between the center hole of the flange and the outer supporting structure.

9. The GIS according to claim 8, characterized in that: An insulating pad is arranged between the pot-type insulator and the top butt flange, and an insulating sleeve is sleeved on the fastening bolt to achieve an insulating spacing between the fastening bolt and the top butt flange.

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