Conducting rod and direct current wall bushing

Abstract

The invention relates to electric wires or cables and protection devices which penetrate through walls, floors or ceilings and are installed in buildings, in particular to a conducting rod and a direct-current wall bushing. The direct-current wall bushing comprises a conducting rod, the conducting rod comprises a current-carrying conductor, one end of the current-carrying conductor is provided with a conductive connector, the other end of the current-carrying conductor is provided with a cover plate, the current-carrying conductor is provided with a center hole, and an insulating ventilation pipe is arranged in the center hole. One end, close to the cover plate, of the insulating ventilation pipe extends out of the cover plate, an air outlet is formed in the end opening of the end, an air inlet is formed in the other end of the insulating ventilation pipe, the insulating ventilation pipe forms a cooling pipe of the current-carrying conductor, and cooling of the interior of the conducting rod is achieved through the insulating ventilation pipe in an air cooling mode; the influence of deformation caused by temperature change on the deflection of the conducting rod is reduced, the bending deformation of the conducting rod is reduced, the uniformity and stability of an electric field in the direct-current wall bushing are ensured as far as possible, and the insulating property of the direct-current wall bushing is ensured.

Description

Technical Field

[0001] The present invention relates to electric wires or cables and protective devices which are installed in buildings through walls, floors or ceilings, and in particular to a conductive rod and a DC wall bushing. Background Art

[0002] The DC wall bushing is a key device that connects the converter valves and DC field equipment in the UHV DC transmission system. It bears the full voltage and current of the system and has the characteristics of meeting stable operation under complex working conditions. When the DC current-carrying conductor needs to pass through a box or wall with a different potential from its own, the DC wall bushing is required.

[0003] DC wall bushings are mainly divided into two types according to the insulation structure: epoxy core SF6 gas comprehensive insulation and pure SF6 gas insulation. The epoxy core SF6 gas comprehensive insulation structure has uniform electric field distribution and is not prone to electric field distortion, but the core design, manufacturing and control process are complex, and the heat dissipation performance is poor; the pure SF6 gas insulation structure is relatively simple, does not involve complex control and manufacturing processes of insulating materials, and pure SF6 gas insulation has the advantages of light weight, strong current capacity, and good seismic performance. The pure SF6 gas insulation structure is a relatively mature and reliable technical route for wall bushing equipment.

[0004] According to the international invention patent with international publication number WO2018 / 032716A1 and international publication date of February 22, 2018, the usual structure of a pure SF6 gas insulation structure is an external insulation structure and an internal structure. The external insulation structure includes an outdoor insulation sleeve and an indoor insulation sleeve connected by a mounting flange, and the internal structure includes a conductive rod. A coaxial shielding electrode is arranged between the conductive rod and the mounting flange to uniform the electric field. SF6 at the designed operating pressure is filled inside the wall bushing as an insulating medium.

[0005] For UHV DC projects, the required creepage distance of pure SF6 gas insulated wall bushing is large, and the length of the central conductive rod can reach 13m, which causes serious sagging problems and is prone to electric field distortion, thereby affecting the insulation performance of the wall bushing. At the same time, the design defects of the current-carrying structure of existing DC wall bushings will cause the bushing to overheat during operation. Summary of the invention

[0006] The object of the present invention is to provide a conductive rod to solve the problem of electric field deformity caused by the sagging of the conductive rod in an ultra-high voltage direct current project.

[0007] At the same time, the purpose of the present invention is also to provide a DC wall bushing to solve the above problems.

[0008] In order to solve the above problems, the conductive rod of the present invention adopts the following technical solutions:

[0009] A conductive rod comprises a current-carrying conductor, one end of which is provided with a conductive joint, and the other end of which is connected to a cover plate. The current-carrying conductor is provided with a central hole, and an insulating ventilation pipe is provided in the central hole. One end of the insulating ventilation pipe close to the cover plate extends outside the cover plate and a port at the end is provided as an air outlet. An air inlet is provided at the other end of the insulating ventilation pipe, and the insulating ventilation pipe forms a cooling pipe for the current-carrying conductor.

[0010] Furthermore, the current-carrying conductor includes an outer tube and an inner tube, the inner diameter of the outer tube is larger than the outer diameter of the inner tube, the outer tube and the inner tube are coaxially arranged, and one end of the outer tube and the inner tube is fixed on the cover plate.

[0011] Furthermore, the outer tube and the inner tube are divided into at least two sections, each two adjacent sections are welded and fixed, and the welding parts of the adjacent sections of the inner tube and the outer tube are provided with plugs.

[0012] Furthermore, the outer tube and the inner tube are fixed to the cover plate and the conductive joint by welding.

[0013] Furthermore, the insulating ventilation tube is coaxially installed with the current-carrying conductor, and two ends of the insulating ventilation tube are fixed relative to two ends of the current-carrying conductor.

[0014] Furthermore, the insulating ventilation pipe is fixed by welding at the contact parts with the cover plate and the conductive joint.

[0015] Beneficial effects: The conductive rod of the present invention is an improved invention. The conductive rod of the present invention comprises a current-carrying conductor, a conductive joint is installed at one end of the current-carrying conductor, a cover plate is installed at the other end, the current-carrying conductor is provided with a central hole, an insulating ventilation pipe is provided in the central hole, one end of the insulating ventilation pipe close to the cover plate extends outside the cover plate and the port of the end is set as an air outlet, an air inlet is provided at the other end of the insulating ventilation pipe, the insulating ventilation pipe forms a cooling pipe for the current-carrying conductor, and the inside of the conductive rod is cooled by air through the insulating ventilation pipe, the influence of deformation caused by temperature change on the deflection of the conductive rod is reduced, the bending deformation of the conductive rod is reduced, the uniformity and stability of the electric field in the DC wall-penetrating pipe is ensured as much as possible, and the insulation performance of the DC wall-penetrating bushing is ensured.

[0016] The DC wall bushing of the present invention adopts the following technical solutions:

[0017] A DC wall bushing comprises a conductive rod, the conductive rod comprises a current-carrying conductor, one end of the current-carrying conductor is provided with a conductive joint, the other end is connected with a cover plate, the current-carrying conductor is provided with a central hole, an insulating ventilation pipe is provided in the central hole, one end of the insulating ventilation pipe close to the cover plate extends outside the cover plate and the port of the end is provided as an air outlet, an air inlet is provided at the other end of the insulating ventilation pipe, and the insulating ventilation pipe forms a cooling pipe for the current-carrying conductor.

[0018] Furthermore, the current-carrying conductor includes an outer tube and an inner tube, the inner diameter of the outer tube is larger than the outer diameter of the inner tube, the outer tube and the inner tube are coaxially arranged, and one end of the outer tube and the inner tube is fixed on the cover plate.

[0019] Furthermore, the outer tube and the inner tube are divided into at least two sections, each two adjacent sections are welded and fixed, and the welding parts of the adjacent sections of the inner tube and the outer tube are provided with plugs.

[0020] Furthermore, the outer tube and the inner tube are fixed to the cover plate and the conductive joint by welding.

[0021] Furthermore, the insulating ventilation tube is coaxially installed with the current-carrying conductor, and two ends of the insulating ventilation tube are fixed relative to two ends of the current-carrying conductor.

[0022] Furthermore, the insulating ventilation pipe is fixed by welding at the contact parts with the cover plate and the conductive joint.

[0023] Beneficial effect: The DC wall bushing of the present invention is an improved invention. The DC wall bushing of the present invention comprises a conductive rod, the conductive rod comprises a current-carrying conductor, a conductive joint is installed at one end of the current-carrying conductor, a cover plate is installed at the other end, the current-carrying conductor is provided with a central hole, an insulating ventilation pipe is arranged in the central hole, one end of the insulating ventilation pipe close to the cover plate extends outside the cover plate and the port of the end is set as an air outlet, an air inlet is arranged at the other end of the insulating ventilation pipe, the insulating ventilation pipe forms a cooling pipe for the current-carrying conductor, and the inside of the conductive rod is cooled by air through the insulating ventilation pipe, the influence of deformation caused by temperature change on the deflection of the conductive rod is reduced, the bending deformation of the conductive rod is reduced, the uniformity and stability of the electric field in the DC wall bushing is ensured as much as possible, and the insulation performance of the DC wall bushing is ensured. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a structural schematic diagram of an embodiment of a conductive rod of the present invention;

[0025] Figure 2 The figure is a schematic structural diagram of an embodiment of the DC wall bushing of the present invention.

[0026] In the figure: 101, insulating ventilation duct; 102, cover plate; 103, outer tube; 104, conductive joint; 105, inner tube; 106, plug; 107, direction of wind entering the ventilation duct; 201, outdoor equalizing ring; 202, end shielding cover; 203, conductive rod; 204, outdoor side hollow composite insulator; 205, grounding shielding cover; 206, wall-penetrating cylinder; 207, indoor side hollow composite insulator; 208, indoor equalizing ring; 209, corrugated pipe. DETAILED DESCRIPTION

[0027] The features and performance of the present invention are further described in detail below in conjunction with the embodiments.

[0028] The temperature of an object is an important factor affecting its anti-flex performance. In the field of DC power transmission and distribution, the length of the wall bushing can reach more than ten meters. During use, due to factors such as temperature rise, it will produce a large degree of deflection. Once this happens, it will cause the electric field around the current-carrying conductor in the wall bushing to be distorted, which is extremely unfavorable. The inventive concept of the present invention is to reduce the temperature of the current-carrying conductor of the wall bushing during operation so that it can maintain a more stable shape, thereby improving the electric field.

[0029] Based on the above invention concept, Figure 1 In a basic embodiment, the conductive rod 203 of the present invention includes a current-carrying conductor, a conductive connector 104 is installed at one end of the current-carrying conductor, and a cover plate 102 is connected to the other end. The current-carrying conductor is provided with a central hole, and an insulating ventilation pipe 101 is provided in the central hole. One end of the insulating ventilation pipe 101 close to the cover plate 102 extends outside the cover plate 102 and the port of the end is set as an air outlet 107. An air inlet is provided at the other end of the insulating ventilation pipe 101. Air enters from the air inlet of the insulating ventilation pipe 101, takes away the heat generated by the conductive rod in the insulating ventilation pipe 101, and is discharged from the air outlet. The conductive rod 203 is helped to dissipate heat by air cooling. Using air cooling to cool the conductive rod 203 can reduce the deformation of the conductive rod 203 caused by thermal expansion, reduce the sagging problem of the conductive rod 203, and avoid electric field distortion caused by radial displacement of the conductive rod 203. Compared with water cooling and oil cooling, the dead weight of the conductive rod 203 is reduced, and the deflection of the conductive rod 203 is effectively reduced.

[0030] like Figure 1 In a preferred embodiment, the current-carrying conductor of the conductive rod of the present invention comprises an inner tube 105 and an outer tube 103, the outer diameter of the inner tube 105 is smaller than the inner diameter of the outer tube 103, the inner tube 105 and the outer tube 103 are coaxially installed, and one end of the outer tube 103 and the inner tube 105 are fixed on the cover plate 102. The current-carrying conductor uses a double-layer structure, which effectively strengthens the overall strength of the conductive rod 203 and has a positive effect on solving the sagging problem of the conductive rod 203. In other embodiments, the current-carrying conductor can also adopt a single-layer hollow structure.

[0031] In a preferred embodiment, the outer tube 103 and the inner tube 105 are divided into at least two sections, and each adjacent section is welded and fixed, and a plug 106 is provided at the welding part of each adjacent section of the inner tube 103 and the outer tube 105. The inner tube 105 and the outer tube 103 are welded and formed as a whole, which avoids the accumulation of space charge of the supporting insulator and the increase of manufacturing process difficulty, optimizes the spatial layout of the wall bushing of the SF6 gas insulation structure, reduces the number of parts, improves the reliability of the whole machine, achieves higher technical parameters, and improves the market competitiveness of the product; at the same time, during the module welding process, a certain pre-compression stress is generated in the cross section of the conductive rod 203, which effectively reduces the tensile stress of the cross section of the conductive rod 203, thereby greatly reducing the deflection of the conductive rod 203. The plug 106 reduces the residual metal debris or suspended matter on the inner wall of the conductive rod 203, and can also play a certain supporting role and reduce the deflection of the conductive rod 203. In other embodiments, the outer tube and the inner tube can also be processed as a whole without segmented processing; the welding of the inner tube and the outer tube is not connected by a plug, and can still be used normally.

[0032] In a preferred embodiment, the outer tube 103 and the inner tube 105 are fixed to the cover plate 102 and the conductive joint 104 by welding, so as to ensure the stable connection of the conductive rod and the sealing of the conductive rod. In other embodiments, the outer tube and the inner tube can also be fixed to the cover plate and the conductive joint by gluing with heat-resistant insulating materials.

[0033] In a preferred embodiment, the insulating ventilation pipe 101 is coaxially installed with the current-carrying conductor, and can be made of glass fiber reinforced plastic: the two ends of the insulating ventilation pipe 101 are fixed relative to the two ends of the current-carrying conductor, and the insulating ventilation pipe 101 can serve as a reinforcing rib of the conductive rod 203 to enhance the strength of the conductive rod 203. In other embodiments, the insulating ventilation pipe may not be fixed to the conductive joint, and the bending of the conductive rod due to different thermal expansion coefficients can be avoided. The contact parts of the insulating ventilation pipe 101, the cover plate 102, and the conductive joint 104 are riveted and fixed to ensure the stability of the conductive rod 203 structure.

[0034] The specific implementation scheme of the DC wall bushing of the present invention is as follows:

[0035] like Figure 2The DC wall bushing of the present invention includes an external insulation structure and an internal structure. The external insulation structure includes an outdoor hollow composite insulator 204 and an indoor hollow composite insulator 207 connected by mounting flanges. The internal structure includes a conductive rod 203. The DC wall bushing is filled with SF6 of the designed operating pressure as an insulating medium. The indoor end of the DC wall bushing adopts a flexible connection structure, which is combined with a bellows 209, an axial seal and a clamping ring structure, and does not use a contact finger connection, thereby reducing the influence of the deformation of the conductive rod 203 due to thermal expansion and contraction, enhancing the sealing of the end, and improving the product reliability. A conductive rod 203 is installed inside the DC wall bushing. The specific implementation of the conductive rod 203 is shown above and will not be repeated.

[0036] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. The patent protection scope of the present invention shall be based on the claims. All equivalent structural changes made using the contents of the description and drawings of the present invention should also be included in the protection scope of the present invention.

Claims

1. A conductive rod, comprising a current-carrying conductor, one end of which is provided with a conductive joint, and the other end of which is connected with a cover plate, characterized in that: The current-carrying conductor is provided with a central hole, in which an insulating ventilation pipe is arranged, one end of the insulating ventilation pipe close to the cover plate extends outside the cover plate and the port of this end is set as an air outlet, and an air inlet is set at the other end of the insulating ventilation pipe, and the insulating ventilation pipe forms a cooling pipe for the current-carrying conductor.

2. The conductive rod according to claim 1, characterized in that: The current-carrying conductor comprises an outer tube and an inner tube, the inner diameter of the outer tube is larger than the outer diameter of the inner tube, the outer tube and the inner tube are coaxially arranged, and one end of the outer tube and the inner tube is fixed on the cover plate.

3. The conductive rod according to claim 2, characterized in that: The outer tube and the inner tube are divided into at least two sections, and each adjacent two sections are welded and fixed, and the welding parts of the adjacent sections of the inner tube and the outer tube are provided with plugs.

4. The conductive rod according to claim 2 or 3, characterized in that: The outer tube and the inner tube are fixed to the cover plate and the conductive joint by welding.

5. The conductive rod according to any one of claims 1 to 3, characterized in that: The insulating ventilation tube is coaxially installed with the current-carrying conductor, and two ends of the insulating ventilation tube are fixed relative to two ends of the current-carrying conductor.

6. The conductive rod according to claim 4, characterized in that: The insulating ventilation tube is coaxially installed with the current-carrying conductor, and two ends of the insulating ventilation tube are fixed relative to two ends of the current-carrying conductor.

7. The conductive rod according to any one of claims 1 to 3 and 6, characterized in that: The insulating ventilation pipe is fixed by welding to the contact parts of the cover plate and the conductive joint.

8. The conductive rod according to claim 4, characterized in that: The insulating ventilation pipe is fixed by welding to the contact parts of the cover plate and the conductive joint.

9. The conductive rod according to claim 5, characterized in that: The insulating ventilation pipe is fixed by welding to the contact parts of the cover plate and the conductive joint.

10. A DC wall bushing, comprising a conductive rod, characterized in that: The conductive rod is the conductive rod according to any one of claims 1 to 9.

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