A pipeline busbar with an outer shell made of prestressed reinforced concrete composite metal inner wall and its manufacturing method

Abstract

The present invention discloses a pipeline busbar having an outer shell with a prestressed reinforced concrete composite metal inner wall and a method for manufacturing the same. The pipeline busbar includes three-phase conductors arranged symmetrically in an equilateral triangle in the axial direction. The inner wall of the pipeline busbar outer shell is made of metal, and the outer surface of the metal material is covered with prestressed reinforced concrete. The three-phase common-box conductors are arranged symmetrically in an equilateral triangle, so that the electromagnetic field at the circumference of the pipeline busbar outer shell is offset by three phases, achieving a zero vector sum of the electromagnetic field at the circumference of the pipeline busbar outer shell. This allows the pipeline busbar outer shell to adopt an outer shell structure with a non-conductive prestressed reinforced concrete composite metal inner wall. Because the concrete has excellent waterproof and corrosion resistance and the metal inner wall has excellent sealing effect, the pipeline busbar of the present invention can be placed in water for long-term operation while meeting internal pressure and sealing requirements, forming an underwater three-phase common-box high-voltage pipeline busbar. The present invention can achieve safe power transmission in long-distance transmission pipelines deep underground.

Description

Technical Field

[0001] The present invention belongs to the field of electromechanical engineering and power transmission and transformation technology, and particularly relates to a pipeline busbar whose outer shell adopts a prestressed reinforced concrete composite metal inner wall and a manufacturing method thereof. Background Art

[0002] Gas-insulated Metal Enclosed Transmission Lines (GILs) transmit electricity using metal conductive rods enclosed in a grounded metal casing and insulated by pressurized gas. SF6 busbars are busbars that use sulfur hexafluoride (SF6) gas as the insulating medium. High-voltage SF6 busbars (GILs) are power transmission equipment with a fully welded metal casing. The internal conductors are supported on the casing by supports or gas-insulated pot insulators. The interior is filled with SF6 insulating gas at a pressure of 0.2 to 0.8 MPa (typically 0.5 MPa for 500 kV).

[0003] Taking 500kV GIL as an example, the outer diameter of its shell is generally about 500mm, and the shell is made of aluminum alloy with a thickness of 20mm. The outer diameter of the conductor is about 20mm, and the conductor is made of aluminum alloy pipe with a thickness of 15mm~20mm.

[0004] Traditional GILSF6 pipeline busbars are made of aluminum alloy. The pipeline busbar shell needs to have the following key characteristics:

[0005] 1. High strength and corrosion resistance: The housing material must be able to withstand the various mechanical stresses and pressures generated during GIL system operation. Because GIL systems often operate in harsh environmental conditions, the housing material must also have good corrosion resistance to prevent damage caused by environmental factors such as humidity, temperature, and chemicals.

[0006] 2. Good sealing: The housing must be able to effectively seal the SF6 gas to prevent it from leaking into the environment. Sealing is crucial to the safe operation of the GIL system, as SF6 gas leakage may cause system performance degradation or even lead to safety accidents.

[0007] 3. Electrical insulation performance: Although SF6 gas itself provides the main insulation function, the shell material should also have certain electrical insulation performance to prevent electrical breakdown or short circuit in extreme cases.

[0008] 4. Thermal stability: When running under high load, the conductor of the GIL will generate a certain amount of heat. Therefore, the shell material should have good thermal stability and be able to withstand certain temperature changes without deformation or damage.

[0009] 5. Fire and explosion-proof performance: Since GIL systems usually operate under high voltage and high current conditions, the casing material must have good fire and explosion-proof performance to prevent fire or explosion in the event of a system failure.

[0010] 6. Easy maintenance and repair: The housing design should be easy for maintenance and repair personnel to operate. For example, easy-to-open inspection ports or passages should be provided to facilitate inspection, repair or replacement of parts when necessary.

[0011] 7. Environmental protection and sustainability: With the increasing demand for environmental protection and sustainability, the material selection of GILSF6 pipeline busbar housing should also consider its impact on the environment. For example, recyclable or biodegradable materials should be selected to reduce pollution to the environment.

[0012] The GILSF6 pipeline busbar casing must possess high strength, corrosion resistance, good sealing, electrical insulation, thermal stability, fire and explosion resistance, and ease of maintenance and repair. Furthermore, with increasing environmental awareness, the environmental friendliness and sustainability of casing materials are becoming important considerations. The structural design of the GILSF6 pipeline busbar and the selection of casing materials that match this design have become pressing issues. Summary of the Invention

[0013] The purpose of the present invention is to provide a pipeline busbar with an outer shell using a prestressed reinforced concrete composite metal inner wall and a manufacturing method thereof. By setting the pipeline busbar structure and selecting an outer shell material that is compatible with the structure, a new underwater three-phase common box high-voltage SF6 pipeline busbar is formed, thereby realizing the safe transmission of electricity through long-distance GIL transmission pipelines in deep underground spaces.

[0014] To achieve the above objectives, the technical solution of the present invention is:

[0015] A pipeline busbar having an outer shell with a prestressed reinforced concrete composite metal inner wall, the pipeline busbar including three-phase conductors, the enclosed space formed by the pipeline busbar outer shell being filled with insulating gas, the three-phase conductors being spatially symmetrically arranged in an equilateral triangle in the axial direction, the vector sum of the electromagnetic fields generated by the three-phase conductors at the pipeline busbar outer shell being zero, the inner wall of the pipeline busbar outer shell being made of metal material, the outer surface of the metal material being covered with prestressed reinforced concrete.

[0016] Furthermore, the inner wall of the metal material and the prestressed reinforced concrete covering the outer surface of the metal material form a prestressed reinforced concrete composite metal shell. The prestressed reinforced concrete composite metal shell is a large-diameter, long-distance sealed pipe shell, and the three-phase common box conductor is located inside the prestressed reinforced concrete composite metal shell.

[0017] Furthermore, the prestressed reinforced concrete composite metal shell is cylindrical, and three pot-type insulator supports with air isolation functions are respectively arranged on the top and bottom inner walls of the cylindrical prestressed reinforced concrete composite metal shell. The pot-type insulator support on the top surface of the cylinder and the pot-type insulator support on the bottom surface are symmetrically arranged. A pot-type insulator support on the top surface of the cylinder and the symmetrical pot-type insulator support on the bottom surface respectively support the two ends of a phase conductor.

[0018] Furthermore, the three pot-type insulator supports on the inner wall of the top surface of the cylinder and the three pot-type insulator supports on the inner wall of the bottom surface of the cylinder are arranged in an equilateral triangle, and the center of each pot-type insulator support is a corner point of the equilateral triangle.

[0019] Furthermore, the prestressed reinforced concrete composite metal shell includes multiple cylindrical single-section pipes, and two adjacent single-section pipes are connected together through a shell airtight docking device. The two ends of the cylinder located in the middle part of the prestressed reinforced concrete composite metal shell are open, one end of the cylinder located at the top of the prestressed reinforced concrete composite metal shell is open, and the other end is the top surface of the prestressed reinforced concrete composite metal shell, and one end of the cylinder located at the bottom end of the prestressed reinforced concrete composite metal shell is open, and the other end is the bottom surface of the prestressed reinforced concrete composite metal shell.

[0020] Furthermore, a plurality of support rings are arranged at intervals inside the prestressed reinforced concrete composite metal shell, and the support rings are disc or ring structures concentric with the GIL shell.

[0021] Furthermore, the support ring sleeve adopts a disc structure, and three circular holes are arranged at intervals on the disc. The three circular holes are arranged in an equilateral triangle, and each circular hole is a corner point of the equilateral triangle. The diameters of the three circular holes are adapted to the outer diameter of each phase conductor. The three circular holes are respectively sleeved on the periphery of a phase conductor. The outer circumference of the support ring sleeve is gap-matched with the inner wall of the prestressed reinforced concrete composite metal shell, and each phase conductor is gap-matched with one of the circular holes. Through the sliding support device, the support ring sleeve can move in the prestressed reinforced concrete composite metal shell and along the axial direction of the prestressed reinforced concrete composite metal shell.

[0022] Furthermore, the pipeline busbar also includes a full immersion system water charging and discharging device, which provides a clean water source, pipelines, and valves to fully immerse the SF6 pipeline busbar with a prestressed reinforced concrete composite metal shell, and the full immersion system runs through the entire GIL path to identify and collect SF6 leakage gas.

[0023] The beneficial effects of the present invention are as follows:

[0024] 1. The three-phase, common-box conductors of the SF6 pipeline busbar of the present invention are arranged symmetrically in an equilateral triangle, achieving three-phase cancellation of the electromagnetic field at the circumference of the SF6 pipeline busbar casing, achieving a zero vector sum of the electromagnetic field at the circumference of the SF6 pipeline busbar casing. This allows the pipeline busbar casing to adopt a shell structure with a non-conductive prestressed reinforced concrete composite metal inner wall. Because the concrete has excellent waterproofness and corrosion resistance, and the metal inner wall has excellent sealing effect, the pipeline busbar of the present invention can be placed in water for long-term operation while meeting the pressure and sealing requirements of the internal SF6, thus forming an underwater three-phase, common-box, high-voltage SF6 pipeline busbar. This invention enables safe power transmission by fully submerged long-distance GIL transmission pipelines deep underground.

[0025] 2. Because the electromagnetic field vector sum is zero around the circumference of the SF6 pipeline busbar housing of the present invention, no magnetic field-induced current from the internal conductors flows through the housing. Therefore, the present pipeline busbar housing eliminates the limitations of conventional pipeline busbar housings in terms of heat generation and heat dissipation. This significantly improves the flow capacity of the GIL pipeline busbar, thereby increasing the transmission capacity of long-distance GILs. This invention provides a novel solution for the use of high-capacity, high-pressure SF6 pipeline busbars in deep underground locations (buried greater than 100 meters) and over extremely long distances (greater than 10 kilometers).

[0026] 3. Since the thermal expansion coefficient of concrete is much lower than that of traditional aluminum alloy shell materials, the thermal expansion adaptability of long-distance pipeline concrete composite shell is better, which can realize the safe transmission of electricity by full immersion in long-distance GIL transmission pipelines deep underground.

[0027] 4. The pipeline busbar shell of the present invention adopts a structure with a prestressed reinforced concrete composite metal inner wall. Due to the high strength and waterproofness of concrete, the pipeline busbar of the present invention is more suitable for use in underwater areas with high water pressure than traditional aluminum alloy shells, and can solve the layout problem of high-voltage busbars over long distances and at extremely deep water depths. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 An example diagram of a new (underwater) SF6 pipeline busbar structure with a prestressed reinforced concrete composite metal inner wall.

[0029] Figure 2 An example diagram of a new (underwater) SF6 pipeline busbar structure with a prestressed reinforced concrete composite metal inner wall.

[0030] Figure 3 An example diagram of a new (underwater) SF6 pipeline busbar structure with a prestressed reinforced concrete composite metal inner wall.

[0031] Wherein: first phase conductor a; second phase conductor b; third phase conductor c; prestressed reinforced concrete composite metal shell 1; shell airtight joint device 2; support ring sleeve 3; sliding support device 4; insulating gas 5. DETAILED DESCRIPTION

[0032] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific examples described herein are some embodiments of the present invention, rather than all embodiments, and are not intended to limit the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0033] An underwater SF6 pipeline busbar with a shell using a prestressed reinforced concrete composite metal inner wall comprises: a three-phase common box conductor, a prestressed reinforced concrete composite metal shell 1, a shell airtight docking device 2, a support ring 3, a sliding support device 4, and an insulating gas 5.

[0034] The three-phase common-box conductors are first phase conductor a, second phase conductor b, and third phase conductor c. In a specific embodiment, the three-phase common-box SF6 pipeline busbar conductor is a 110kV to 1000kV high-voltage SF6 pipeline busbar (GIL), which is a high-voltage power transmission equipment. It uses a fully welded metal shell. The internal three-phase conductors a, b, and c are supported by supports or pot-type insulators with air insulation within the enclosed space formed by the shell.

[0035] The prestressed reinforced concrete composite metal shell 1 has an inner wall made of metal material, which may be an aluminum alloy material, and an outer surface of the metal material is provided with prestressed reinforced concrete.

[0036] The prestressed reinforced concrete composite metal shell 1 can be a large-diameter, long-distance sealed pipe shell, used for a closed pressure pipe of a GIL three-phase common box. It is a metal composite concrete structure. At the same time, the pipe of this material has a certain rigidity and can meet the internal pressure load of 0.5~5.0Mpa.

[0037] The three-phase common box conductor is located inside the prestressed reinforced concrete composite metal shell 1. The prestressed reinforced concrete composite metal shell 1 is a columnar body, such as a cylinder or a cuboid. In the specific embodiment of the present invention, a cylindrical prestressed reinforced concrete composite metal shell 1 is used, such as Figure 1 、 Figure 2 and Figure 3As shown, three pot-type insulator supports with air insulation functions are respectively provided on the top and bottom inner walls of the cylindrical prestressed reinforced concrete composite metal shell 1. The pot-type insulator supports on the top surface of the cylinder are symmetrically arranged with the pot-type insulator supports on the bottom surface. One pot-type insulator support on the top surface of the cylinder and the symmetrical pot-type insulator support on the bottom surface respectively support the two ends of the first phase conductor a, the second phase conductor b, or the third phase conductor c.

[0038] The three pot-type insulator supports on the inner wall of the top surface of the cylinder are arranged in an equilateral triangle, and the three pot-type insulator supports on the inner wall of the bottom surface of the cylinder are arranged in an equilateral triangle. The opening center of each pot-type insulator support is a corner point of the equilateral triangle.

[0039] Because the first phase conductor a, the second phase conductor b, and the third phase conductor c are relatively long, in a specific embodiment of the present invention, the prestressed reinforced concrete composite metal shell 1 is assembled from multiple single-section pipes, each of which is a cylinder. Adjacent single-section pipes are assembled together using a shell airtight docking device 2. The cylinder located in the middle of the prestressed reinforced concrete composite metal shell 1 has openings at both ends. The cylinder located at the top of the prestressed reinforced concrete composite metal shell 1 has an opening at one end, and the other end forms the top surface of the prestressed reinforced concrete composite metal shell 1. The cylinder located at the bottom of the prestressed reinforced concrete composite metal shell 1 has an opening at one end, and the other end forms the bottom surface of the prestressed reinforced concrete composite metal shell 1.

[0040] The space between the inner wall of the prestressed reinforced concrete composite metal shell 1 and the first phase conductor a, the second phase conductor b, and the first phase conductor c is filled with SF6 insulating gas 5, which is 0.2Mpa~0.8Mpa SF6 insulating gas inside the GIL (usually 0.5Mpa for 550kV).

[0041] The enclosure airtight docking device 2 enables long-distance interconnection and airtight sealing of the individual pipe sections within the prestressed reinforced concrete composite metal enclosure 1. This device can be an external flange located at the interface between two adjacent individual pipe sections. Each of these interfaces is provided with an external flange to allow bolted connection of the two adjacent individual pipe sections. These external flanges can be pre-placed during the concrete pouring of the pipeline busbar enclosure. The enclosure airtight docking device 2 is a detachable device for connecting the three-phase GIL enclosures, segmented by gas chamber, end-to-end. This device connects the concrete composite metal enclosure segments and creates an airtight seal.

[0042] A plurality of support rings 3 are arranged at intervals inside the prestressed reinforced concrete composite metal shell 1, and the number of support rings 3 is set according to actual needs. The support ring 3 adopts a disc or annular structure concentric with the GIL shell. The support ring 3 is used to provide radial limiting support for the three-phase common box conductor in the prestressed reinforced concrete composite metal shell 1. In a specific embodiment, the support ring 3 adopts a disc structure, and three circular holes are arranged at intervals on the disc. The three circular holes are arranged in an equilateral triangle, and each circular hole is a corner point of the equilateral triangle. The diameters of the three circular holes are adapted to the outer diameters of the first phase conductor a, the second phase conductor b, and the third phase conductor c. The three circular holes are respectively arranged on the outer periphery of the first phase conductor a, the second phase conductor b, and the third phase conductor c to provide radial support for the first phase conductor a, the second phase conductor b, and the third phase conductor c. The outer circumference of the support ring 3 is loosely coupled with the inner wall of the prestressed reinforced concrete composite metal shell 1. The first phase conductor a, the second phase conductor b, and the third phase conductor c are loosely coupled with the three circular holes, respectively. Through the sliding support device 4, the support ring 3 is able to move within the prestressed reinforced concrete composite metal shell 1 and along the axial direction of the prestressed reinforced concrete composite metal shell 1. In a specific embodiment, four protrusions are evenly spaced on the outer circumference of the support ring 3, and the line connecting two oppositely disposed protrusions passes through the center of the support ring 3. Four elongated grooves are provided on the inner wall of the prestressed reinforced concrete composite metal shell 1 along the axial direction. Each protrusion is coupled with one of the elongated grooves, and each protrusion is clamped in one of the elongated grooves. The protrusions loosely couple with the grooves. When thermal expansion and contraction occur, the protrusions slide along the grooves, allowing the support ring 3 to move along the axial direction within the prestressed reinforced concrete composite metal shell 1.

[0043] In the present invention, the basin-type insulator supports for the three-phase conductors are arranged in an equilateral triangle, and the three circular holes of the support ring 3 supporting the three-phase conductors are arranged in an equilateral triangle. This results in a spatially symmetrical arrangement of the three-phase conductors in the axial (path) direction, forming an equilateral triangle. As a result, the vector sum of the electromagnetic fields generated by the three-phase conductors at the casing is zero, effectively canceling out the three phases. This achieves a zero vector sum of the electromagnetic fields at the circumference of the GIL casing, enabling the pipeline busbar to adopt a casing structure with a non-conductive prestressed reinforced concrete composite metal inner wall. Because concrete offers excellent waterproofing and the metal inner wall provides excellent sealing, the prestressed reinforced concrete composite metal casing can operate underwater for long periods while maintaining the required internal SF6 pressure and sealing, thus forming a novel underwater three-phase common-chamber high-voltage SF6 pipeline busbar.

[0044] The present invention also discloses a method for manufacturing a pipeline busbar whose outer shell adopts a prestressed reinforced concrete composite metal inner wall, the method comprising:

[0045] S1: Production of pipeline busbar shell

[0046] S11: Four long strip grooves are evenly spaced on the metal material, and a plurality of cylindrical single-section pipes are produced using the metal material. Four protrusions evenly spaced on the outer circumference of the support ring sleeve 3 are respectively stuck in a long strip groove, and each protrusion is loosely fitted with a long strip groove. The single-section pipe located at one end of the pipe busbar shell includes a bottom surface and an opening at the top surface. The single-section pipe located at the other end of the pipe busbar shell includes a top surface and an opening at the bottom surface. Both ends of the single-section pipe located in the middle of the pipe busbar shell are open. One or more support ring sleeves 3 are provided in each single-section pipe according to actual needs.

[0047] S12: pouring concrete on the outer surface of the cylindrical single-section pipe, and reserving an external flange on the periphery of the opening of the single-section pipe when pouring concrete.

[0048] S13: Install three pot-type insulator supports on the inner wall of the bottom surface of the single-section pipeline at one end of the pipeline busbar housing, and the three pot-type insulator supports are arranged in an equilateral triangle on the bottom surface; install three pot-type insulator supports on the inner wall of the top surface of the single-section pipeline at the other end of the pipeline busbar housing, and the three pot-type insulator supports are arranged in an equilateral triangle on the top surface;

[0049] S2: One end installation of three-phase conductor

[0050] One end of the first phase conductor a, the second phase conductor b, and the third phase conductor c are respectively installed at the openings of three pot-type insulator supports on the bottom surface of the single-section pipeline at one end of the pipeline busbar shell.

[0051] S3: Pipeline assembly

[0052] The single-section pipes are assembled together using external flange bolts. During the assembly process, the other ends of the first phase conductor a, the second phase conductor b, and the third phase conductor c are respectively passed through a circular hole on the support ring sleeve 3 until the single-section pipe at the other end of the pipe busbar shell is assembled. After the assembly is completed, the other ends of the first phase conductor a, the second phase conductor b, and the third phase conductor c are respectively installed at the openings of the three pot insulator supports on the top surface of the single-section pipe at the other end of the pipe busbar shell.

[0053] Taking the GIL (three-phase common insulator) with a rated voltage of 550 kV and a rated current of 1000 A of a large underground hydropower station as an example, the system of the present invention is as follows.

[0054] like Figure 1 As shown, a PCCP (prestressed concrete steel liner) with an inner diameter of about 1500mm is used as the SF6 pipeline for the three-phase common box 500kV GIL (conductor outer diameter 180mm), which can be a vertical or horizontal section of the GIL.

[0055] According to the method of the present invention, the three-phase conductors in the same box are arranged inside the pipeline by using a disk or annular structure concentric with the GIL shell. The centers of the openings of the three-phase conductors on the disk a, b, and c are distributed in an equilateral triangle to ensure that the three-phase conductors are arranged symmetrically in the equilateral triangle space in the axis (path) direction. The vector sum of the electromagnetic field generated at the shell is 0, that is, the three phases cancel each other out.

[0056] Compute the fields due to a single conductor:

[0057] Use the Biot-Savart law or more advanced electromagnetic field theory to calculate the electric and magnetic fields for a single conductor at the GIL housing.

[0058] Superposition principle:

[0059] The fields generated by the three-phase conductors a, b, and c are vector-superimposed to obtain the total field at the GIL casing.

[0060] Consider the impact of the GIL enclosure: The GIL enclosure may act as a shield and affect the internal field. The enclosure material, thickness, and conductivity need to be considered.

[0061] Electric field calculation:

[0062] For the electric field generated by a point charge or a line charge, the electric field strength E can be expressed as:

[0063] E=kQ / r2

[0064] Or for the electric field due to the line current (considering the Coulomb gauge of the magnetic vector potential):

[0065] E=sin(θ)(μ0I) / 2πr

[0066] Where k is the electric field constant, Q is the charge, r is the distance, μ0 is the magnetic permeability of vacuum, I is the current, and θ is the angle between the current direction and the direction of the observation point.

[0067] For three-phase systems, the phase difference of the currents and the geometry of the conductor arrangement need to be considered, and complex number representation and phasor analysis can be used.

[0068] Magnetic field calculation:

[0069] For the magnetic field generated by the line current, the magnetic field intensity H on the plane perpendicular to the current line can be expressed as:

[0070] H=I / 2πr

[0071] Likewise, for a three-phase system, we need to consider the phase difference of the currents and the geometry of the conductor arrangement.

[0072] For this example, 500kV, rated current 5000A, outer diameter of the shell is 1500mm, outer diameter of each phase of the three-phase conductor is 180mm, the three phases are arranged in a right triangle symmetrically and concentrically with the shell, and the center spacing of the conductors is 600mm.

[0073] Conductor outer diameter Dc=180mm

[0074] Conductor center distance d=600 mm

[0075] Shell outer diameter Ds = 1500mm

[0076] Voltage level U=500kV

[0077] Rated current I=5000A

[0078] Due to the symmetry of the three-phase conductors, it can be calculated that at certain points of the enclosure, these magnetic field vectors will cancel each other out (especially on the axis perpendicular to the plane of the conductors), but at other points, they will not completely cancel each other out. Integrating along the circumference, due to the spatial symmetry of the three phases and the 120-degree phase difference between abc, the vector superposition of the electromagnetic fields will also cancel each other out.

[0079] Since the sum of the electromagnetic field vectors at the GIL shell is approximately 0 under the above-mentioned symmetrical arrangement of the conductors in an equilateral triangle, conditions are created for the use of non-conductive non-metallic materials.

[0080] Prestressed reinforced concrete composite metal material is used as the GIL shell, which can be a large-diameter and long-distance sealed pipe shell, and is used for a closed pressure pipeline for GIL three-phase common box. It is a metal composite concrete structure, and the concrete composite metal GIL shell airtight docking device can be used to connect the concrete composite metal shell in sections to form an airtight seal.

[0081] While achieving long-distance interconnection and airtightness, the pipe made of this material has a certain rigidity and strength, which can meet the internal pressure load of 0.5~5.0Mpa, which is 2.0Mpa in this case.

[0082] The 500kV SF6 pipeline busbar three-phase common box conductor adopts the metal shell full welding method, and the internal a, b, and c three-phase conductors are supported on the shell by supports or pot-type insulators with air isolation function.

[0083] The pressure of SF6 gas inside the GIL is 0.5Mpa, and the internal pressure of the shell of the prestressed concrete reinforced composite metal lining is 2Mpa, which fully meets the shell rigidity and internal insulating gas pressure requirements of the GIL.

[0084] The fully immersed system water filling and discharging device is used for the SF6 pipeline busbar of the present invention and can operate underwater for a long time. The device provides a clean water source, pipelines, and valves, and fully immerses the SF6 pipeline busbar, forming a fully immersed system throughout the entire GIL path, which can identify and collect SF6 leakage gas.

[0085] The above embodiments are merely examples for clarity of explanation and are not intended to limit the embodiments. Those skilled in the art will appreciate that other variations or modifications based on the above descriptions are possible. It is not necessary and impossible to enumerate all embodiments here. Obvious variations or modifications arising therefrom remain within the scope of protection of the present invention.

Claims

1. A method for manufacturing a pipeline busbar with an outer shell made of prestressed reinforced concrete and a composite metal inner wall, wherein the pipeline busbar includes a three-phase conductor and is characterized by: The enclosed space formed by the pipeline busbar shell is filled with SF6 insulating gas; The three-phase conductors are arranged symmetrically in a regular triangle in the axial direction. The vector sum of the electromagnetic fields generated by the three-phase conductors at the pipeline busbar housing is zero. The inner wall of the pipeline busbar housing is made of metal material, and the outer surface of the metal material is covered with prestressed reinforced concrete. The pipeline busbar housing is installed underwater, and the pipeline busbar is laid over a distance greater than 10 km. The outer diameter of the housing is 1500 mm. The outer diameter of each of the three-phase conductors is 180 mm, and the center spacing between adjacent conductors is 600 mm. The method comprises: S1: Production of pipeline busbar shell; S2: installation at one end of the three-phase conductor; One end of the first phase conductor (a), the second phase conductor (b), and the third phase conductor (c) are respectively installed at the openings of three pot-type insulator supports on the bottom surface of the single-section pipeline at one end of the pipeline busbar shell; S3: Pipeline assembly; Assemble the individual pipe sections together. During the assembly process, the other ends of the first phase conductor (a), the second phase conductor (b), and the third phase conductor (c) are respectively passed through a circular hole on the support ring sleeve (3) until the single pipe section at the other end of the pipe busbar housing is assembled. After the assembly is completed, the other ends of the first phase conductor (a), the second phase conductor (b), and the third phase conductor (c) are respectively installed at the openings of the three pot-type insulator supports on the top surface of the single pipe section at the other end of the pipe busbar housing; Wherein, the S1 step includes: S11: four long strip grooves are evenly spaced apart on the metal material, and a plurality of cylindrical single-section pipes are produced using the metal material, and four protrusions evenly spaced apart on the outer circumference of the support ring sleeve (3) are respectively stuck in one of the long strip grooves, and each protrusion is loosely fitted in one of the long strip grooves; S12: pouring concrete on the outer surface of the cylindrical single-section pipe, and reserving an external flange on the periphery of the opening of the single-section pipe during the pouring of the concrete; S13: Three pot-type insulator supports are installed on the inner wall of the bottom surface of the single-section pipe at one end of the pipe busbar housing, and three pot-type insulator supports are installed on the inner wall of the top surface of the single-section pipe at the other end of the pipe busbar housing. The three pot-type insulator supports on the bottom and top surfaces are arranged in an equilateral triangle.

2. The method for manufacturing a pipeline busbar with an outer shell made of prestressed reinforced concrete and a composite metal inner wall according to claim 1, characterized in that: The inner wall of the metal material and the prestressed reinforced concrete covering the outer surface of the metal material form a prestressed reinforced concrete composite metal shell (1). The prestressed reinforced concrete composite metal shell (1) is a large-diameter, long-distance sealed pipeline shell, and the three-phase common box conductor is located inside the prestressed reinforced concrete composite metal shell (1).

3. The method for manufacturing a pipeline busbar with an outer shell made of prestressed reinforced concrete and a composite metal inner wall according to claim 2, characterized in that: The prestressed reinforced concrete composite metal shell (1) is cylindrical, and three pot-type insulator supports with air isolation functions are respectively arranged on the top surface and the inner wall of the bottom surface of the cylindrical prestressed reinforced concrete composite metal shell (1). The pot-type insulator supports on the top surface of the cylinder and the pot-type insulator supports on the bottom surface are symmetrically arranged, and a pot-type insulator support on the top surface of the cylinder and a symmetrical pot-type insulator support on the bottom surface respectively support the two ends of a phase conductor.

4. The method for manufacturing a pipeline busbar with an outer shell made of prestressed reinforced concrete and a composite metal inner wall according to claim 3, characterized in that: The three pot-type insulator supports on the inner wall of the top surface of the cylinder and the three pot-type insulator supports on the inner wall of the bottom surface of the cylinder are arranged in an equilateral triangle, and the opening center of each pot-type insulator support is a corner point of the equilateral triangle.

5. The method for manufacturing a pipeline busbar with an outer shell made of prestressed reinforced concrete and a composite metal inner wall according to claim 2, characterized in that: The prestressed reinforced concrete composite metal shell (1) comprises a plurality of cylindrical single-section pipes, wherein two adjacent single-section pipes are connected together via a shell airtight butt joint device (2); the two ends of the cylinder located in the middle of the prestressed reinforced concrete composite metal shell (1) are open; one end of the cylinder located at the top of the prestressed reinforced concrete composite metal shell (1) is open, and the other end is the top surface of the prestressed reinforced concrete composite metal shell (1); and one end of the cylinder located at the bottom of the prestressed reinforced concrete composite metal shell (1) is open, and the other end is the bottom surface of the prestressed reinforced concrete composite metal shell (1).

6. The method for manufacturing a pipeline busbar with an outer shell made of prestressed reinforced concrete and a composite metal inner wall according to claim 5, characterized in that: The shell airtight butt joint device (2) is an outer flange arranged at the interface of two adjacent single-section pipes, and the two adjacent single-section pipe interfaces are connected by outer flange bolts.

7. The method for manufacturing a pipeline busbar with an outer shell made of prestressed reinforced concrete and a composite metal inner wall according to claim 2, characterized in that: A plurality of support rings (3) are arranged at intervals inside the prestressed reinforced concrete composite metal shell (1), and the support rings (3) are disc or ring structures concentric with the GIL shell.

8. The method for manufacturing a pipeline busbar with an outer shell made of prestressed reinforced concrete and a composite metal inner wall according to claim 7, characterized in that: The support ring sleeve (3) adopts a disc structure, and three circular holes are arranged at intervals on the disc. The three circular holes are arranged in an equilateral triangle, and each circular hole is a corner point of the equilateral triangle. The diameters of the three circular holes are adapted to the outer diameter of each phase conductor. The three circular holes are respectively sleeved on the periphery of a phase conductor. The outer circumference of the support ring sleeve (3) is gap-matched with the inner wall of the prestressed reinforced concrete composite metal shell (1), and each phase conductor is gap-matched with one of the circular holes. Through the sliding support device (4), the support ring sleeve (3) can move within the prestressed reinforced concrete composite metal shell (1) and along the axial direction of the prestressed reinforced concrete composite metal shell (1).

9. The method for manufacturing a pipeline busbar with an outer shell made of prestressed reinforced concrete and a composite metal inner wall according to claim 7, characterized in that: Four protrusions are evenly spaced on the outer circumference of the support ring sleeve (3), and a line connecting two oppositely arranged protrusions passes through the center of the support ring sleeve (3). Four long strip-shaped grooves are arranged on the inner wall of the prestressed reinforced concrete composite metal shell (1) along the axial direction, and each protrusion cooperates with one of the long strip-shaped grooves. Each protrusion is stuck in one of the long strip-shaped grooves, and the protrusion and the groove are loosely matched.

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