CN213546101U

CN213546101U - Built-in current transformer

Info

Publication number: CN213546101U
Application number: CN202022123345.XU
Authority: CN
Inventors: 朱传运; 张皓祺; 殷秀玲; 李伟强; 董斌; 蒋会昂; 申健; 马靖; 王小东; 黄鑫; 秦泳
Original assignee: State Grid Corp of China SGCC; Pinggao Group Co Ltd; Henan Pinggao Electric Co Ltd
Current assignee: State Grid Corp of China SGCC; Pinggao Group Co Ltd; Henan Pinggao Electric Co Ltd
Priority date: 2020-09-24
Filing date: 2020-09-24
Publication date: 2021-06-25
Anticipated expiration: 2030-09-24

Abstract

The utility model relates to a built-in current transformer, including shell and interior support section of thick bamboo-coil assembly, interior support section of thick bamboo-coil assembly includes tip flange portion, interior support section of thick bamboo portion and coil, wherein, the coil inboard through sticky fixed or the fixed mode of pouring and interior support section of thick bamboo portion fixed mounting, need not set up closing device in the upper and lower direction specially again, interior support section of thick bamboo portion need not additionally extend again, has saved the high space. And the radial contraction section is arranged on the shell, the inner diameter of the radial contraction section is not larger than that of the inner support cylinder part, the radial contraction section is positioned above the inner support cylinder part and forms a shielding gap with the inner support cylinder part in the up-down direction, so that the radial contraction section forms shielding protection on the top of the inner support cylinder part, a shielding cover is not required to be arranged on the top of the inner support cylinder part, the height space for arranging the shielding cover is saved, the axial size of the whole current transformer is effectively shortened, and the miniaturization development idea of the current transformer is met.

Description

Built-in current transformer

Technical Field

The utility model relates to a built-in current transformer.

Background

The current transformer is one of the important parts of the GIS, mainly functions to convert a large current on the primary side in the system into a small current according to a specified proportion, isolate a large current on a primary loop, provide current for various instruments and meters, relay protection and the like in a secondary system, and is important electrical equipment in a power system.

The existing built-in current transformer is characterized in that an airtight cavity is formed inside a shell, an inner support cylinder is arranged in the airtight cavity, a coil is sleeved outside the inner support cylinder, the local structure is shown in fig. 1, the inner support cylinder 20 and the coil 26 are both located inside the shell 25, a top fixing plate 22 is fixedly arranged at the top of the inner support cylinder 20, a pressing device 23 is arranged on the top fixing plate 22, and the pressing device 23 presses the coil 26 downwards through a pressing plate 24, so that the coil 26 and the inner support cylinder 20 are fixedly assembled. In order to prevent the sharp corner at the top end of the inner support cylinder 20 from causing electric field distortion to cause internal discharge, a shielding cover 21 is usually arranged at the top end of the inner support cylinder 20, the shielding cover 21 is fixedly mounted on a top fixing plate 22 through a bolt, and the shielding cover 21 is bent inwards to realize shielding protection on the top end of the inner support cylinder. Similar structures are also available as current transformers from the company of the chinese invention patent with the publication number CN 102930967B.

The built-in current transformer has the problem of excessive parts due to the mode that the compressing device is used for compressing and fixing the coil through the compression plate, the top fixing plate, the compressing device and the compression plate need to be correspondingly arranged, the inner supporting cylinder needs to be arranged to protrude out of the coil for a certain length, otherwise, the compressing device cannot be installed, in addition, due to the protruding arrangement of the inner supporting cylinder, a shielding cover needs to be arranged corresponding to the tip end of the inner supporting cylinder, the shielding cover occupies a part of height space, the height size of the current transformer is larger, and the miniaturization development of the current transformer is not facilitated.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to provide a built-in current transformer to solve among the prior art built-in current transformer because adopt closing device and shield cover to lead to the great technical problem of current transformer overall height.

In order to achieve the above object, the utility model provides a built-in current transformer's technical scheme is: a built-in current transformer comprising:

the shell is provided with a secondary wiring terminal;

a primary center conductor extending in an up-down direction in an axial direction and disposed in the housing;

the inner support cylinder-coil assembly comprises an end flange part, an inner support cylinder part and a coil, wherein the end flange part and the lower end of the inner support cylinder part are integrally arranged or fixedly connected in a split manner, the coil is sleeved outside the inner support cylinder part at intervals, and the inner side of the coil is fixedly assembled with the inner support cylinder part in a gluing fixing or pouring fixing manner;

the end flange part is fixedly assembled with the lower end of the shell in a sealing way, so that the inner support cylinder part and the coil are positioned in the shell;

the primary central conductor is arranged in the center of the inner support cylinder part;

the shell is provided with a radial contraction section, the inner diameter of the radial contraction section is not larger than that of the inner support cylinder part, the radial contraction section is located above the inner support cylinder part and forms a shielding gap with the inner support cylinder part in the up-down direction, and the radial contraction section forms shielding protection on the top of the inner support cylinder part.

The beneficial effects are that: the utility model provides an among the built-in current transformer, the coil passes through sticky fixed or the fixed mode of pouring and supports section of thick bamboo fixed assembly together with interior, need not set up closing device on the upper and lower direction specially again, and interior support section of thick bamboo need not additionally extend again, has saved the high space. And moreover, the shielding protection is formed by utilizing the radial contraction section of the shell, a shielding cover is not required to be arranged at the top of the inner supporting cylinder, and the height space for arranging the shielding cover is saved, so that the axial size of the whole current transformer is effectively shortened, and the miniaturization development idea of the current transformer is met.

As a further improvement, the inner edge of the lower end of the radial contraction section is in a round corner structure.

The beneficial effects are that: the inner edge of the lower end of the radial contraction section is of a round angle structure, so that the breakdown voltage can be effectively improved, and the safety performance is improved.

As a further improvement, the housing comprises a main cylinder section, the inner diameter of the main cylinder section is larger than that of the radial contraction section, the main cylinder section is located below the radial contraction section and is in integral transition connection with the radial contraction section, the main cylinder section corresponds to the coil in the up-down direction, and the coil is arranged at intervals.

The beneficial effects are that: the main cylinder section and the radial contraction section are in integrated transition connection, so that the shell can be machined and manufactured conveniently.

As a further refinement, the radially constricted section is located at the top of the housing such that the housing forms a top end constriction.

The beneficial effects are that: the radial contraction section is positioned at the top of the shell, so that the overall size of the shell is small.

As a further improvement, the shielding gap is 3-6 mm.

As a further improvement, the inner diameter dimension of the radial contraction section is equal to the inner diameter dimension of the inner support cylinder part.

The beneficial effects are that: the inner diameter size of the radial contraction section is equal to that of the inner support cylinder part, so that the radial contraction section is matched with an electric field of the inner support cylinder part and matched with a primary central conductor positioned at the central position of the inner support cylinder part, the condition similar to a coaxial electric field can be formed, the electric field distortion caused by the top end of the inner support cylinder part is effectively prevented, and the internal discharge is avoided.

As a further improvement, when the inner side of the coil is fixedly fixed with the inner supporting cylinder part in a pouring and fixing mode, the inner side of the coil and the inner supporting cylinder part are fixedly assembled by adopting epoxy resin pouring materials.

As a further improvement, the upper end of the primary central conductor is fixedly assembled with an upper supporting insulator, the lower end of the primary central conductor is fixedly assembled with a lower supporting insulator, the upper supporting insulator is fixedly assembled with the upper end of the shell in a sealing manner, and the lower supporting insulator is fixedly assembled with the end flange part or the lower end of the shell in a sealing manner.

The beneficial effects are that: the two supporting insulators are adopted to support and assemble the primary central conductor, so that the structure is simple and the installation is convenient.

As a further improvement, when the lower supporting insulator is fixedly sealed with the end flange portion, the end flange portion has an outer connecting portion and an inner connecting portion, the inner connecting portion is located radially inside the outer connecting portion at the end flange portion, the outer connecting portion is fixedly sealed with the lower end of the housing, the inner connecting portion is fixedly sealed with the lower supporting insulator, and the upper and lower thickness dimension of the inner connecting portion is greater than that of the outer connecting portion.

The beneficial effects are that: the end flange is provided with the inner side connecting part and the outer side connecting part, and the thickness of the inner side connecting part is larger than that of the outer side connecting part, so that the production cost can be reduced as much as possible under the condition of ensuring the connection strength.

As a further improvement, the outer connecting portion forms an outer edge of the end flange portion, and the inner connecting portion forms an inner edge of the end flange portion.

The beneficial effects are that: the outer side connecting portion form the outer side edge, and the inner side connecting portion form the inner side edge, so that the end flange portion, the lower end of the shell and the lower supporting insulator are conveniently assembled respectively.

Drawings

Fig. 1 is a schematic structural diagram of a conventional built-in current transformer;

fig. 2 is a schematic structural diagram of embodiment 1 of the built-in current transformer provided by the present invention.

Description of reference numerals:

1-upper support insulator, 2-primary central conductor, 3-housing, 31-radial contraction section, 32-main cylinder section, 4-inner support cylinder section, 5-coil, 6-epoxy resin casting layer, 7-end flange section, 71-outer connecting section, 72-inner connecting section, 8-lower support insulator, 9-secondary wiring plate, 10-conductive seat, 20-inner support cylinder, 21-shielding cover, 22-top fixing plate, 23-pressing device, 24-pressing plate, 25-housing, 26-coil.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the invention, i.e., the described embodiments are only some, but not all embodiments of the invention. The components of embodiments of the present invention, as generally described and illustrated in the figures herein, may be arranged and designed in a wide variety of different configurations.

Thus, the following detailed description of the embodiments of the present invention, presented in the accompanying drawings, is not intended to limit the scope of the invention, as claimed, but is merely representative of selected embodiments of the invention. Based on the embodiment of the present invention, all other embodiments obtained by the person skilled in the art without creative work belong to the protection scope of the present invention.

It is noted that relational terms such as "first" and "second," and the like, may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, elements recited by the phrase "comprising an … …" do not exclude the inclusion of such elements in processes or methods.

In the description of the present invention, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" when they are used are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; either directly or indirectly through intervening media, or may be interconnected between two elements. The specific meaning of the above terms in the present invention can be understood by those skilled in the art from the specific situation.

In the description of the present invention, it should be noted that, unless explicitly stated or limited otherwise, the term "provided" may be used in a broad sense, for example, the object of "provided" 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 a non-detachable connection. The specific meaning of the above terms in the present invention can be understood by those skilled in the art from the specific situation.

The present invention will be described in further detail with reference to examples.

The utility model provides a specific embodiment 1 of built-in current transformer:

as shown in fig. 2, the current transformer in this embodiment includes a housing 3, an inner support bobbin-coil assembly, two support insulators, and a primary center conductor 2.

The casing 3 is a unitary structure, including radial contraction section 31 and the main barrel section 32 of lower part at the top, and main barrel section 32 internal diameter size is greater than radial contraction section 31 internal diameter size, and main barrel section 32 is located radial contraction section 31 below and with radial contraction section 31 integrative transition joint. The radially constricted section 31 is located at the top of the housing 3 so that the housing 3 is formed in the form of a top end constriction.

The inner support cylinder-coil assembly comprises an end flange part 7, an inner support cylinder part 4 and a coil 5, wherein the end flange part 7 and the inner support cylinder part 4 are integrally machined, the end flange part 7 is positioned at the lower end of the inner support cylinder part 4, the coil 5 is sleeved outside the inner support cylinder part 4 at intervals, the inner side of the coil 5 is fixedly assembled with the inner support cylinder part 4 in a pouring and fixing mode, specifically, epoxy resin pouring materials can be poured between the inner side of the coil 5 and the inner support cylinder part 4 to form an epoxy resin pouring layer 6, and if a gap exists between the coil and the end flange part, the epoxy resin pouring materials can also enter under the pressure action, as shown in figure 2, so that the coil 5, the inner support cylinder part 4 and the end flange part are fixedly assembled together to form the inner support cylinder-coil assembly. During assembly, the inner support cylinder-coil assembly can be assembled firstly and then is arranged in the shell 3, so that the assembly efficiency can be effectively improved.

In this embodiment, the epoxy resin casting is selected for casting and fixing, which does not react with sulfur hexafluoride gas to affect the insulation performance. In other embodiments, other suitable casting materials can be selected for casting and fixing, and mainly do not react with the insulating gas.

To ensure proper assembly, an outer connecting portion 71 and an inner connecting portion 72 are provided on the end flange portion 7, the outer connecting portion 71 forming an outer edge of the end flange portion 7, and the inner connecting portion 72 forming an inner edge of the end flange portion 7, such that the inner connecting portion 72 is located radially inside the outer connecting portion 71 at the end flange portion, the outer connecting portion 71 is in sealing fixed assembly with the lower end of the housing 3, and the inner connecting portion 72 is in sealing fixed assembly with the lower supporting insulator 8.

Further, in order to ensure the connection strength without excessively increasing the cost, the inner connecting portion 72 has a larger vertical thickness than the outer connecting portion 71, so that the inner edge of the end flange portion 7 is arranged to protrude with respect to the outer edge.

In this embodiment, interior support section of thick bamboo portion 4 and tip flange portion 7 structure as an organic whole, can adopt the direct integrated processing of machining mode to obtain inboard connecting portion and the outside connecting portion that thickness size differs, and processing is comparatively convenient.

When the inner support cylinder-coil assembly is fixedly installed in the housing 3, the outer side connecting portion of the end flange portion 7 is sealingly and fixedly fitted with the lower end of the housing 3, and the inner support cylinder portion 4 and the coil 5 are both located inside the housing 3.

In the present embodiment, the inner diameter dimension of the radially constricted section 31 coincides with the inner diameter dimension of the inner support tube section 4 in the radial direction of the outer shell 3. In the up-down direction, the main cylinder section 32 corresponds to the coil 5 and is arranged at an interval with the coil 5, the radial contraction section 31 is positioned above the inner support cylinder section 4, a shielding gap is formed between the radial contraction section 31 and the inner support cylinder section 4 in the up-down direction, so that the radial contraction section 31 forms shielding protection for the top of the inner support cylinder section 4, the shielding gap cannot be too large or too small, effective shielding protection cannot be formed when the shielding gap is too large, breakdown conduction is easy to occur when the shielding gap is too small, and the shielding gap is generally selected to be 3-6 mm.

Note that, in the built-in current transformer, the radial contraction section 31 here must not be conducted to the inner support cylindrical portion 4, so as to avoid the case 3 and the inner support cylindrical portion 4 forming a closed circuit, which results in generating a loop current under an ac magnetic field.

In addition, in the present embodiment, the breakdown electric field is increased, and the inner edge of the lower end of the radial contraction section 31 has a rounded structure.

The primary central conductor 2 extends in the up-down direction, the upper end of the primary central conductor is fixedly provided with an upper supporting insulator 1, the lower end of the primary central conductor is fixedly provided with a lower supporting insulator 8, actually, the central positions of the two supporting insulators are respectively provided with a conductive insert, the opposite inner sides of the conductive devices of the two supporting insulators are respectively and fixedly provided with a conductive seat 10 in a conductive manner, and the upper end and the lower end of the primary central conductor 2 are correspondingly and electrically inserted into the two conductive seats 10. Wherein, go up support insulator 1 and the fixed mounting in shell 3 upper end, specifically, go up support insulator 1 and the sealed fixed mounting of the upper flange portion of radial contraction section 31 upper end, lower support insulator 8 then with the sealed fixed mounting of the inboard connecting portion of tip flange portion 7, and then make two support insulators all with shell 3 fixed mounting together to support the central conductor 2 fixed inside shell 3 once, and, once central conductor 2 arranges in the department of the central point of interior support section of thick bamboo portion 4.

In order to realize the normal work of the current transformer, the shell 3 is provided with a wiring terminal port, the inner side of the wiring terminal port is provided with a secondary wiring disc 9, and a secondary wiring terminal is arranged at the wiring terminal port, so that the wire outlet is convenient.

In this embodiment, the upper ends of the upper supporting insulator 1 and the housing 3 are fixedly sealed, the end flange portion 7 and the lower end of the housing 3 are fixedly sealed, and the end flange portion 7 and the lower supporting insulator 8 are fixedly sealed by arranging a sealing ring between the two, and the two are fixedly assembled by a threaded fastener, so that a hermetic sealing cavity is formed inside the housing 3, and an insulating gas such as sulfur hexafluoride can be injected into the hermetic sealing cavity to achieve a good insulating effect, and meanwhile, the coil 5 is also in a gas insulating environment to form a built-in current transformer.

In this embodiment, coil 5 direct casting is fixed on interior support section of thick bamboo portion 4, need not set up closing device in addition again to, because utilize the shielding protection on the radial contraction section 31 on the shell 3 to support section of thick bamboo portion 4 top internally, also need not set up the shield cover again, both combine together, have not only reduced spare part quantity, have effectively simplified overall structure, have improved assembly efficiency, have shortened current transformer's axial length in addition effectively, are favorable to the miniaturized development of current transformer.

The utility model provides a specific embodiment 2 of built-in current transformer:

the difference from example 1 is mainly that: in example 1, the end flange portion and the lower end of the inner support tube portion were integrally provided. In this embodiment, the end flange portion and the inner support cylinder portion are separately and fixedly connected, for example, by welding.

The utility model provides a specific embodiment 3 of built-in current transformer:

the difference from example 1 is mainly that: in embodiment 1, the coil is fixedly assembled with the inner support cylinder by forming an annular resin casting layer on the inner side of the coil by casting epoxy resin casting. In this embodiment, an adhesive may be provided between the coil inner side and the inner support tube portion, and the coil inner side may be fixedly attached to the inner support tube portion by means of adhesive fixation. It is important to note that the glue is selected so as not to react with the insulating gas and degrade the gas insulation performance.

The utility model provides a specific embodiment 4 of built-in current transformer:

the difference from example 1 is mainly that: in embodiment 1, the lower support insulator is fixedly assembled with the inner connecting portion of the end flange portion. In this embodiment, the lower supporting insulator may be directly fixedly assembled with the lower end of the housing, at this time, a step structure may be provided at the lower end of the housing, the end flange portion is located in the step, and the lower supporting insulator is located outside the step, so as to realize the sealing and fixing assembly of the end flange portion and the lower supporting insulator with the housing, respectively.

Of course, in other embodiments, the lower supporting insulator may also be directly stacked on the end flange portion, and in this case, the lower supporting insulator, the end flange portion and the lower end of the housing are directly and fixedly assembled together by the same fastening bolt.

The utility model provides a specific embodiment 5 of built-in current transformer:

the difference from example 1 is mainly that: in example 1, the radially constricted section is located at the top of the housing, such that the housing forms a top end constriction. In this embodiment, the radial constriction may also be located in the middle of the housing, as long as it is located above the inner support cylinder and forms a corresponding shielding gap. At this time, the inner diameter dimension of the radially constricted section may be smaller than the inner diameter dimension of the inner support tube section.

Finally, it should be noted that the above mentioned embodiments are only preferred embodiments of the present invention, and not intended to limit the present invention, and although the present invention has been described in detail with reference to the foregoing embodiments, it will be apparent to those skilled in the art that modifications may be made without inventive effort to the technical solutions described in the foregoing embodiments, or equivalents may be substituted for some of the technical features. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A built-in current transformer comprising:

the shell is provided with a secondary wiring terminal;

it is characterized by also comprising:

2. The built-in current transformer according to claim 1, wherein the lower end inner edge of the radial contraction section is in a round corner structure.

3. The built-in current transformer according to claim 2, wherein the housing comprises a main cylinder section, the inner diameter of the main cylinder section is larger than that of the radial contraction section, the main cylinder section is located below the radial contraction section and is in integral transition connection with the radial contraction section, the main cylinder section corresponds to the coil in the up-down direction, and the coil is arranged at intervals.

4. The built-in current transformer of claim 3, wherein the radially constricted section is located at the top of the enclosure such that the enclosure forms a top end constriction.

5. The built-in current transformer according to any of claims 1 to 4, characterized in that the shielding gap is 3-6 mm.

6. The built-in current transformer according to any one of claims 1 to 4, characterized in that the radial constriction has an inner diameter dimension equal to the inner diameter dimension of the inner support cylinder.

7. The built-in current transformer according to any one of claims 1 to 4, wherein when the inner side of the coil is fixedly fixed with the inner support cylinder part by pouring, the inner side of the coil is fixedly assembled with the inner support cylinder part by epoxy resin pouring.

8. The built-in current transformer according to any one of claims 1 to 4, wherein the upper end of the primary central conductor is fixedly assembled with an upper supporting insulator, the lower end of the primary central conductor is fixedly assembled with a lower supporting insulator, the upper supporting insulator is fixedly assembled with the upper end of the housing in a sealing manner, and the lower supporting insulator is fixedly assembled with the end flange part or the lower end of the housing in a sealing manner.

9. The built-in current transformer according to claim 8, wherein the end flange portion has an outer connecting portion and an inner connecting portion when the lower supporting insulator is sealingly and fixedly secured to the end flange portion, the inner connecting portion being located radially inward of the outer connecting portion in the end flange portion, the outer connecting portion being sealingly and fixedly secured to the lower end of the case, the inner connecting portion being sealingly and fixedly secured to the lower supporting insulator, and an upper and lower thickness dimension of the inner connecting portion being greater than an upper and lower thickness dimension of the outer connecting portion.

10. The built-in current transformer according to claim 9, wherein the outer connecting portion forms an outer edge of the end flange portion, and the inner connecting portion forms an inner edge of the end flange portion.