Pure gas type direct current wall bushing

Abstract

The invention discloses a pure gas type direct current wall bushing which comprises a current-carrying conducting rod, a connecting cylinder and a shielding cylinder, the connecting cylinder is connected with an outdoor insulator and an indoor insulator, the connecting cylinder is provided with an inner flange, the connecting cylinder, the outdoor insulator and the indoor insulator jointly form a containing space, and the containing space is filled with insulating gas with preset air pressure. The shielding cylinder is located in the containing space, the middle of the outer surface of the shielding cylinder is connected with the inner flange, the current-carrying conducting rod is located in the containing space and penetrates through the shielding cylinder, one end of the current-carrying conducting rod is connected with the outdoor current-carrying terminal, the other end of the current-carrying conducting rod is connected with the indoor current-carrying terminal, and the indoor current-carrying terminal or the outdoor current-carrying terminal is connected with the head cover plate through the telescopic pipe. The pure gas type direct current wall bushing provided by the invention can better solve the contradiction between the insulating property and the thermal property.

Description

Technical Field

[0001] The invention relates to the technical field of power electrical equipment, and in particular to a pure gas type direct current wall bushing. Background Art

[0002] Flexible DC transmission has gradually become an important development direction of UHV DC transmission due to its flexible operation mode. Wall bushing, as one of the core equipment of DC transmission, is an important component of the power system, responsible for the input and output of current in the entire transmission system. Flexible DC wall bushing has more complicated operating conditions because it bears AC and DC composite current and voltage. It not only bears AC and DC voltage, but also carries harmonic current. The electrical insulation, thermal and mechanical properties restrict each other, and the contradiction between insulation performance and thermal performance is more prominent. Summary of the invention

[0003] In view of this, an object of the present invention is to provide a pure gas type DC wall bushing to better resolve the contradiction between insulation performance and thermal performance.

[0004] In order to achieve the above object, the present invention provides the following technical solutions:

[0005] A pure gas type DC wall bushing, comprising:

[0006] A connecting tube, connecting an outdoor insulator and an indoor insulator, wherein the connecting tube is provided with an inner flange, and the connecting tube, the outdoor insulator and the indoor insulator jointly form a receiving space, wherein the receiving space is filled with insulating gas at a preset pressure;

[0007] A shielding cylinder is located in the accommodating space, and a middle portion of an outer surface of the shielding cylinder is connected to the inner flange;

[0008] A current-carrying conductive rod is located in the accommodating space and passes through the shielding cylinder. One end of the current-carrying conductive rod is connected to an outdoor current-carrying terminal, and the other end is connected to an indoor current-carrying terminal. The indoor current-carrying terminal or the outdoor current-carrying terminal is connected to the head cover plate through a telescopic tube.

[0009] Optionally, the pure gas type DC wall bushing comprises:

[0010] A spring device is located in the accommodating space and connected to the head cover plate where the telescopic tube is located. The elastic restoring force of the spring device applies an axial pulling force to the current-carrying conductive rod to reduce the deflection.

[0011] Optionally, in the above pure gas type DC wall bushing, the spring device comprises:

[0012] A mounting seat, fixedly connected to the head cover plate;

[0013] A guide rod is arranged parallel to the axial direction of the current-carrying conductive rod, and one end of the guide rod is fixedly connected to the mounting seat;

[0014] A pressing plate, sleeved on the current-carrying conductive rod;

[0015] A spring, sleeved on the guide rod, with two ends of the spring respectively abutting against the mounting seat and the pressure plate;

[0016] The first nut is threadably connected to the current-carrying conductive rod and abuts against a side of the pressing plate facing away from the spring.

[0017] Optionally, in the above pure gas type DC wall bushing, one end of the guide rod close to the pressing plate is provided with a thread and connected with a second nut, and the second nut is located on a side of the pressing plate facing away from the spring.

[0018] Optionally, in the above pure gas type DC wall bushing, one end of the guide rod away from the pressing plate is provided with a thread and connected to the first threaded hole of the mounting seat.

[0019] Optionally, in the above pure gas type DC wall bushing, the first nut is provided with a plurality of second threaded holes evenly distributed around the axis of the first nut, and the second threaded holes are connected with set screws for abutting against the pressure plate.

[0020] Optionally, in the above-mentioned pure gas type DC wall bushing, the spring device includes a pressure head sleeved on the guide rod, and the pressure head is located between the spring and the pressure plate.

[0021] Optionally, in the above-mentioned pure gas type DC wall bushing, both ends of the shielding tube are provided with outward-turned curled edges.

[0022] Optionally, in the above-mentioned pure gas type DC wall bushing, the current-carrying conductive rod is configured as a pipe fitting.

[0023] Optionally, the pure gas type DC wall bushing comprises:

[0024] An outdoor pressure equalizing cover is located in the accommodation space and is fixedly connected to the outdoor head cover plate, and covers the end of the current-carrying conductive rod;

[0025] The indoor pressure equalizing cover is located in the accommodating space and is fixedly connected to the indoor head cover plate, and covers the end of the current-carrying conductive rod.

[0026] The pure gas type DC wall bushing provided by the present invention has the following beneficial effects:

[0027] The wall bushing provided by the present invention provides an insulating layer surrounding the current-carrying conductive rod with insulating gas, and does not have traditional insulating structures such as epoxy glue impregnated paper cores, so that better heat dissipation performance can be achieved. Moreover, the present invention arranges a shielding tube inside the wall bushing as a substitute for traditional insulating structures such as epoxy glue impregnated paper cores in improving the electric field strength. The shielding tube, as a tube structure, only occupies a small volume inside the wall bushing, and will not affect the heat dissipation performance of the wall bushing. At the same time, the present invention connects the indoor current-carrying terminal or the outdoor current-carrying terminal to the head cover plate through a telescopic tube, which can allow the current-carrying conductive rod to produce more telescopic deformation due to thermal expansion and contraction, thereby making the working temperature range of the wall bushing wider. In summary, the pure gas type DC wall bushing provided by the present invention can better solve the contradiction between insulation performance and thermal performance, so that the insulation performance and thermal performance can be designed more balanced. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0029] Figure 1 is a schematic diagram of a pure gas type DC wall bushing provided in an embodiment of the present invention;

[0030] Figure 2 yes Figure 1 A schematic diagram of an outdoor head of a pure gas type DC wall bushing is shown;

[0031] Figure 3 yes Figure 1 A schematic diagram of an indoor head of a pure gas type DC wall bushing is shown;

[0032] Figure 4 yes Figure 3 An enlarged schematic diagram of the spring device in FIG.

[0033] The markings in the figure are:

[0034] 100, connecting tube; 101, inner flange; 200, shielding tube; 300, current-carrying conductive rod;

[0035] 410, outdoor insulator; 420, indoor insulator;

[0036] 510, outdoor equalizing ring; 511, first connecting portion; 520, indoor equalizing ring; 521, second connecting portion; 522, indoor second cover plate;

[0037] 610, outdoor current-carrying terminal; 620, indoor current-carrying terminal; 621, telescopic tube;

[0038] 710, outdoor head cover; 720, indoor first cover;

[0039] 810, outdoor pressure equalizing cover; 820, indoor pressure equalizing cover;

[0040] 900, spring device; 901, mounting seat; 902, guide rod; 903, spring; 904, pressure head; 905, pressure plate; 906, second nut; 907, first nut. DETAILED DESCRIPTION

[0041] The technical solutions in the embodiments of the present invention will be described below in conjunction with the accompanying drawings in the embodiments of the present invention. Based on the technical solutions in the present invention, all other technical solutions obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0042] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "examples" or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of this specification. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine different embodiments or examples described in this specification and the features of different embodiments or examples, unless they are contradictory.

[0043] In the description of this specification, relational terms such as first and second, etc. 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 "comprise", "include" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the statement "comprises a ..." does not exclude the presence of other identical elements in the process, method, article or device including the element.

[0044] See also Figure 1~Figure 4The embodiment of the present invention provides a pure gas type DC wall bushing (hereinafter referred to as "wall bushing"), including a current-carrying conductive rod 300, a connecting tube 100 and a shielding tube 200, wherein the connecting tube 100 connects the outdoor insulator 410 and the indoor insulator 420, and the connecting tube 100 is provided with an inner flange 101, and the connecting tube 100, the outdoor insulator 410 and the indoor insulator 420 jointly form a receiving space, and the receiving space is filled with insulating gas at a preset pressure. The shielding tube 200 is located in the receiving space, and the middle of the outer surface of the shielding tube 200 is connected to the inner flange 101, the current-carrying conductive rod 300 is located in the receiving space and passes through the shielding tube 200, one end of the current-carrying conductive rod 300 is connected to the outdoor current-carrying terminal 610, and the other end is connected to the indoor current-carrying terminal 620, and the indoor current-carrying terminal 620 or the outdoor current-carrying terminal 610 is connected to the head cover plate through a telescopic tube 621.

[0045] The insulating gas inside the wall bushing is filled in the accommodating space formed by the connecting tube 100, the outdoor insulator 410 and the indoor insulator 420, that is, the outdoor head and the indoor head of the wall bushing are closed, and the enclosed space inside the wall bushing is filled with insulating gas to form a gas insulation environment with a preset air pressure. The insulating gas forms a first layer of insulation for the current-carrying conductive rod 300 inside the wall bushing, and the outdoor insulator 410 and the indoor insulator 420 form a second layer of insulation for the current-carrying conductive rod 300 outdoors and indoors respectively. The wall bushing of the present invention is called a pure gas DC wall bushing because the insulating structure inside the wall bushing is composed of insulating gas, and no insulating structure such as an epoxy glue impregnated paper core for the current-carrying conductive rod 300 is arranged inside the wall bushing. On the basis of eliminating the insulating structure such as epoxy impregnated paper core, the present invention sets a shielding tube 200 inside the wall bushing to make the electric field strength inside the wall bushing meet the requirements of safe operation, and avoid the electric field breaking through the internal insulating layer formed only by insulating gas. It should be understood that the shielding tube 200 is made of conductive material, and is electrically connected to the connecting tube 100 through the inner flange 101. The outer flange (not marked in the figure) of the connecting tube 100 is connected to the wall to realize the installation and grounding of the wall bushing on the wall.

[0046] The two ends of the current-carrying conductive rod 300 are respectively connected to the indoor current-carrying terminal 620 and the outdoor current-carrying terminal 610, and one of the indoor current-carrying terminal 620 and the outdoor current-carrying terminal 610 is connected to the head cover plate (i.e., the cover plate that closes the end of the wall bushing to form a closed space) through the telescopic tube 621, so that the current-carrying conductive rod 300 can produce more telescopic deformation due to thermal expansion and contraction without affecting the structural safety of the wall bushing. Therefore, the wall bushing can work in a wider temperature range. In some embodiments, the telescopic tube 621 can be set as a corrugated tube. Of course, in other embodiments, the telescopic tube 621 can also be set in other forms, as long as it can be telescopically deformed along the axial direction of the current-carrying conductive rod 300, for example, the telescopic tube 621 can be set as a combined tube structure including multiple telescopic joints.

[0047] In the wall bushing provided by the present invention, since the epoxy glue impregnated paper core and the like are eliminated inside and only the insulating gas is used to provide the insulating structure, better heat dissipation performance can be achieved. The shielding tube 200, as a tube structure, only occupies a small volume inside the wall bushing and will not affect the heat dissipation performance of the wall bushing. At the same time, when the indoor current-carrying terminal 620 or the outdoor current-carrying terminal 610 is connected to the head cover plate through the telescopic tube 621, the operating temperature range of the wall bushing can be set wider. It can be seen that the wall bushing provided by the present invention can better solve the contradiction between insulation performance and thermal performance, so that the insulation performance and thermal performance can be designed more balanced.

[0048] In order to further reduce the overall weight of the wall bushing, the shielding tube 200 can be set as an aluminum part. Of course, in other embodiments, the shielding tube 200 can also be made of other conductive materials, such as copper, but it will be heavier than aluminum. In order to reduce the weight of the current-carrying conductive rod 300, the current-carrying conductive rod 300 can be set as a pipe fitting, that is, the current-carrying conductive rod 300 is set to have a hollow structure. The connecting tube 100 is the wall-penetrating part of the wall bushing. The connecting tube 100 and the inner flange 101 can be set as an integrated structure, or they can be set as two parts connected by fasteners. For example, the inner flange 101 is fixedly connected to the connecting tube 100 by bolts and sealing rings. The outdoor insulator 410 and the indoor insulator 420 can adopt a conventional structure. For example, they can be set as a hollow composite insulator composed of a glass fiber reinforced plastic pipe and silicone rubber with an umbrella skirt, that is, the outer surface of the glass fiber reinforced plastic pipe is covered with silicone rubber.

[0049] When the wall bushing passes through the wall horizontally, the current-carrying conductive rod 300 may produce a certain deflection due to its own gravity. In order to minimize the deflection of the current-carrying conductive rod 300, the wall bushing may include: a spring device 900, which is located in the accommodating space and connected to the head cover plate where the telescopic tube 621 is located. The elastic restoring force of the spring device 900 applies an axial pulling force to the current-carrying conductive rod 300 to reduce the deflection. The spring device 900 is installed on the head cover plate where the telescopic tube 621 is located. The spring device 900 applies an axial pulling force to the current-carrying conductive rod 300 to make the current-carrying conductive rod 300 in a straight state. Because the deflection of the current-carrying conductive rod 300 is small under the action of the elastic restoring force of the spring device 900, the current-carrying conductive rod 300 is not easy to contact the inner wall of the shielding tube 200 due to excessive deflection, which is conducive to improving the safety of the wall bushing.

[0050] In some embodiments, the spring device 900 may include: a mounting seat 901, fixedly connected to the head cover; a guide rod 902, arranged parallel to the axial direction of the current-carrying conductive rod 300, one end of the guide rod 902 is fixedly connected to the mounting seat 901; a pressure plate 905, sleeved on the current-carrying conductive rod 300; a spring 903, sleeved on the guide rod 902, the two ends of the spring 903 are respectively against the mounting seat 901 and the pressure plate 905; a first nut 907, threadedly connected to the current-carrying conductive rod 300 and against the side of the pressure plate 905 facing away from the spring 903. Figure 3 and Figure 4 In the exemplary embodiment, the head cover plate where the telescopic tube 621 is located is an indoor head cover plate, and the indoor head cover plate includes an indoor first cover plate 720 connected to the head of the indoor insulator 420 and an indoor second cover plate 522 connected to the middle of the indoor first cover plate 720. The telescopic tube 621 is located on the outside of the indoor head cover plate, that is, the telescopic tube 621 is located outside the above-mentioned accommodation space filled with insulating gas. The mounting seat 901 is located in the accommodation space and is fixedly connected to the indoor first cover plate 720 and the indoor second cover plate 522 by bolts. The spring 903 is sleeved on the guide rod 902 and elastically deforms along the guide rod 902. The elastic restoring force of the spring 903 is transmitted to the first nut 907 through the pressure plate 905. Since the first nut 907 is threadedly connected to the current-carrying conductive rod 300, the elastic restoring force of the spring 903 applies an axial pulling force (that is, along the guide rod 902) to the current-carrying conductive rod 300. Figure 4 It is easy to understand that the guide rods 902 are arranged to be distributed around the current-carrying conductive rod 300, and each guide rod 902 is sleeved with a spring 903. The elastic restoring force of these springs 903 acts on the pressure plate 905, and the pressure plate 905 can move axially relative to the current-carrying conductive rod 300.

[0051] Of course, in other embodiments, the spring device 900 can be set to other structural forms, for example, a set of cylindrical parts outside the current-carrying conductive rod 300 is fixed on the mounting seat 901, and a spring is sleeved on the outer surface of the cylindrical part. The spring is used to directly abut the first nut 907 on the current-carrying conductive rod 300, which can also apply axial tension to the current-carrying conductive rod 300.

[0052] In some embodiments, one end of the guide rod 902 close to the pressure plate 905 may be provided with a thread and connected with a second nut 906, and the second nut 906 is located on the side of the pressure plate 905 facing away from the spring 903. The second nut 906 can facilitate the assembly of the spring device 900. During the assembly process, the pressure plate 905 can be pushed by screwing the second nut 906 to compress the spring 903 to a certain extent, so that when the first nut 907 is screwed onto the current-carrying conductive rod 300, the pressure plate 905 does not form resistance to the first nut 907, making the installation of the first nut 907 more labor-saving. After the first nut 907 is installed in place, the second nut 906 is adjusted in a direction away from the pressure plate 905 so that the pressure plate 905 and the first nut 907 are against each other. It is easy to understand that the second nut 906 can limit the distance that the pressure plate 905 moves outward along the guide rod 902, so that the pressure plate 905 will not fall off the guide rod 902, which is conducive to improving the reliability of the spring device 900.

[0053] In some embodiments, one end of the guide rod 902 away from the pressure plate 905 may be provided with a thread and connected to the first threaded hole of the mounting seat 901. The guide rod 902 is connected to the mounting seat 901 through a threaded connection, which can facilitate the installation of the guide rod 902. Of course, in other embodiments, the guide rod 902 can be fixed to the mounting seat 901 by other means such as welding. In order to facilitate the adjustment of the preload force of the spring 903, the first nut 907 can be provided with a plurality of second threaded holes evenly distributed around the axis of the first nut 907. The second threaded hole is connected with a set screw for abutting against the pressure plate 905. By adjusting the length of the set screw extending out of the first nut 907, the compression amount of the spring 903 can be changed, thereby achieving the adjustment of the preload force.

[0054] In some embodiments, the spring device 900 may include a pressure head 904 sleeved on the guide rod 902, and the pressure head 904 is located between the spring 903 and the pressure plate 905. By providing the pressure head 904, the spring device 900 can be assembled more conveniently, and the pressure head 904 and the pressure plate 905 are in surface contact, so that the elastic restoring force of the spring 903 is transmitted to the pressure plate 905 with a larger contact area, which can reduce the damage to the pressure plate 905. The side of the pressure head 904 facing away from the pressure plate 905 can be provided with a convex head connected and matched with the spring 903, and the convex head plays a shaping role on the end of the spring 903, so that the end of the spring 903 always remains round, which is conducive to avoiding the spring 903 from contacting the surface of the guide rod 902 during the compression deformation process.

[0055] In some embodiments, both ends of the shielding tube 200 may be provided with an outward curling edge, which can better reduce the electric field strength, help improve safety, and extend the service life of the insulating gas. In order to further balance the electric field strength, the wall bushing may include: an outdoor equalizing cover 810, which is located in the accommodation space and fixedly connected to the outdoor head cover 710, and covers the end of the current-carrying conductive rod 300; an indoor equalizing cover 820, which is located in the accommodation space and fixedly connected to the indoor head cover, and covers the end of the current-carrying conductive rod 300. The insulating gas can be set to SF6 or air, etc. In order to ensure a good insulation effect, the preset pressure of the insulating gas can be set to 0.5 MPa~0.7 MPa, for example, set to 0.6 MPa.

[0056] See also Figure 1~Figure 3 The head of the wall bushing may be provided with an outdoor grading ring 510 and an indoor grading ring 520. The outdoor grading ring 510 is fixedly connected to the outdoor head cover plate 710 via a first connection portion 511, and the indoor grading ring 520 is fixedly connected to the indoor head cover plate via a second connection portion 521. The grading ring can improve voltage distribution and enable the wall bushing to work more safely in the power transmission system.

[0057] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0058] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. The present invention will not be limited to the embodiments shown herein, but should be consistent with the broadest scope consistent with the principles and novel features disclosed herein.

Claims

1. A pure gas type DC wall bushing, comprising: A connecting tube, connecting an outdoor insulator and an indoor insulator, wherein the connecting tube is provided with an inner flange, and the connecting tube, the outdoor insulator and the indoor insulator jointly form a receiving space, wherein the receiving space is filled with insulating gas at a preset pressure; A shielding cylinder is located in the accommodating space, and a middle portion of an outer surface of the shielding cylinder is connected to the inner flange; A current-carrying conductive rod is located in the accommodating space and passes through the shielding cylinder. One end of the current-carrying conductive rod is connected to an outdoor current-carrying terminal, and the other end is connected to an indoor current-carrying terminal. The indoor current-carrying terminal or the outdoor current-carrying terminal is connected to the head cover plate through a telescopic tube.

2. The pure gas type DC wall bushing according to claim 1, characterized in that: include: A spring device is located in the accommodating space and connected to the head cover plate where the telescopic tube is located. The elastic restoring force of the spring device applies an axial pulling force to the current-carrying conductive rod to reduce the deflection.

3. The pure gas type DC wall bushing according to claim 2, characterized in that: The spring device comprises: A mounting seat, fixedly connected to the head cover plate; A guide rod is arranged parallel to the axial direction of the current-carrying conductive rod, and one end of the guide rod is fixedly connected to the mounting seat; A pressing plate, sleeved on the current-carrying conductive rod; A spring, sleeved on the guide rod, with two ends of the spring respectively abutting against the mounting seat and the pressure plate; The first nut is threadably connected to the current-carrying conductive rod and abuts against a side of the pressing plate facing away from the spring.

4. The pure gas type DC wall bushing according to claim 3, characterized in that: One end of the guide rod close to the pressure plate is provided with a thread and connected with a second nut, and the second nut is located on a side of the pressure plate facing away from the spring.

5. The pure gas type DC wall bushing according to claim 4, characterized in that: One end of the guide rod away from the pressing plate is provided with a thread and connected to the first threaded hole of the mounting seat.

6. The pure gas type DC wall bushing according to claim 3, characterized in that: The first nut is provided with a plurality of second threaded holes evenly distributed around the axis of the first nut, and the second threaded holes are connected with set screws for abutting against the pressure plate.

7. The pure gas type DC wall bushing according to claim 3, characterized in that: The spring device comprises a pressure head sleeved on the guide rod, and the pressure head is located between the spring and the pressure plate.

8. The pure gas type DC wall bushing according to any one of claims 1 to 7, characterized in that: Both ends of the shielding tube are provided with outwardly turned curling edges.

9. The pure gas type DC wall bushing according to claim 8, characterized in that: The current-carrying conductive rod is configured as a pipe.

10. The pure gas type DC wall bushing according to claim 8, characterized in that: include: An outdoor pressure equalizing cover is located in the accommodation space and is fixedly connected to the outdoor head cover plate, and covers the end of the current-carrying conductive rod; The indoor pressure equalizing cover is located in the accommodating space and is fixedly connected to the indoor head cover plate, and covers the end of the current-carrying conductive rod.

Images