A grounding reactor assembly method for a direct current power system and a grounding reactor

Abstract

This invention belongs to the field of reactor technology, specifically relating to an assembly method and a grounding reactor for DC power systems. The method involves winding a coil with a heat dissipation shield and mounting it with a high-voltage shield. Stacked iron cores form the reactor body unit, which undergoes semi-finished product testing. The reactor body unit is installed inside the housing using anti-vibration pads, and an insulator with a lead-line shield and conductive base is installed on the upper end cap. The upper end cap and housing are then installed, and the low-voltage gas-filled bushing assembly is fixed to the connecting flange. The base frame unit is connected to the connecting flange, and the high-voltage bushing unit is installed on the upper end cap to form a closed cavity. Vacuuming, filling with insulating gas, and leak testing are performed, followed by a complete unit test and gas composition analysis. The method reduces losses through pre-installed shields and equalizing rings, and the anti-vibration pads effectively absorb vibration energy, reducing operating noise. Airtightness treatment and testing ensure operational reliability and insulation performance.

Description

Technical Field

[0001] This invention belongs to the field of reactor technology, specifically relating to a method for assembling a grounding reactor for a DC power system and the grounding reactor itself. Background Technology

[0002] In power systems, with the construction of ultra-high voltage direct current (UHVDC) projects and the large-scale grid connection of new energy sources, the level of short-circuit current in the system continues to rise, placing demands on the current-limiting capacity, insulation reliability, and operational stability of grounding equipment. Grounding reactors, as key devices connected between the neutral point of converter transformers or the DC bus and ground, undertake multiple functions, including suppressing single-phase short-circuit currents, balancing inter-electrode voltages, limiting the rate of increase of fault currents, and assisting in arc extinction.

[0003] Currently, the shielding and voltage equalization structures at the ends of reactor coils and high-voltage leads are unreasonable, and the shielding structure is not tightly bonded to the coil and core. This causes the electric field to concentrate in critical areas, making corona discharge and partial discharge phenomena more likely. Partial discharge can continuously erode the coil insulation layer and bushing insulation components, leading to a gradual decline in insulation performance, insulation breakdown, reactor failure, and shutdown, thus affecting the stable operation of the entire power system.

[0004] When a reactor is running, the coil generates heat as current flows through it. The external cooling system, however, has poor contact between the heat sink and the coil's heating element, resulting in high thermal resistance and inefficient heat transfer, leading to localized temperature increases in the coil. Excessive temperature accelerates the aging of insulation components such as the enameled wire insulation layer and insulation cylinder, shortening their lifespan. Furthermore, high temperatures can affect the permeability of the iron core, causing instability in the reactor's reactive performance.

[0005] When reactors using this technology are in operation, the iron core will experience periodic vibrations due to magnetostriction. This is caused by insufficient clamping force of the iron core clamps on the iron core laminations, resulting in a large vibration amplitude. This vibration will be transmitted to components such as the casing and base frame, generating strong operating noise. The vibration can also cause flange connection bolts to loosen, sealing surfaces to misalign, leading to leakage of insulating gas and damaging the electrical performance of the reactor. Summary of the Invention

[0006] This invention provides a method for assembling grounding reactors for DC power systems. The invention divides the entire unit into units, and each assembly unit can be carried out in sections or simultaneously, which improves production efficiency, reduces the product defect rate, enhances the structural stability, insulation sealing and transportation reliability of the reactor, and facilitates on-site maintenance.

[0007] Includes the following steps: S1. The assembly of the device unit is completed by winding the coil, installing the shielding cover and stacking the iron core, and the performance of the semi-finished product is verified.

[0008] S2. Separately and independently assemble the high-pressure bushing unit containing conductive and equalizing structures, the low-pressure inflatable bushing assembly with inflation function, and the base frame unit for support.

[0009] S3. The pre-assembled unit is positioned and installed inside the housing using anti-vibration pads, and the insulator with lead wire shield and conductive base is pre-installed on the upper end cap.

[0010] S4. Securely connect the upper end cap to the shell and install the pre-assembled low-pressure inflatable sleeve assembly onto the corresponding interface of the connecting flange.

[0011] S5. Connect the base frame unit to the bottom of the connecting flange to form an overall support, and then install the pre-assembled high-pressure bushing unit to the top interface of the upper end cap to form a closed cavity structure.

[0012] S6. Perform vacuuming on the entire product cavity after final assembly, and fill it with insulating gas after the vacuum requirement is met, and conduct a sealing test to ensure the airtightness of the product.

[0013] S7. Conduct routine whole-machine tests and gas composition analysis on products that have passed the airtightness test to fully verify whether the electrical performance and internal gas state meet the factory standards.

[0014] It should be further explained that S1 specifically includes the following: S11. On the insulating cylinder, enameled wire is wound in a rectangular spiral along the axial direction to form a coil; During the winding process, three mutually insulating annular heat dissipation shields are sequentially embedded at the preset radial interlayer positions of the coil; after the winding and shield embedding processes are completed, the insulating cylinder with the coil and heat dissipation shields is placed in an oven for curing. S12. Fit the cylindrical high-voltage shield along the axial direction onto the outside of the coil that has been cured, ensuring that there is a uniform insulation gap between the inner wall of the high-voltage shield and the outermost turns of the coil.

[0015] S13. Position and place the laminated iron core on one side and its corresponding iron core clamp; place a set of shielding plate and insulating plate composed of conductive shielding plate and insulating material plate tightly against the end face of the side iron core; and fit the coil module assembled in step S along the core column axis of the iron core. S14. On the other side opposite to step S, first place another set of shielding plates and insulating plates, then connect the other side of the laminated iron core with the iron core part that has been initially assembled to form a closed magnetic circuit. S15. Apply a preset AC test voltage to the assembled and locked unit and measure the excitation characteristic curve; measure the impedance error under the specified current to verify whether the electrical performance meets the preset parameters.

[0016] It should be further explained that S2 specifically includes the following: S21. Insert the high-voltage bushing insulating cylinder into the high-voltage bushing umbrella sleeve. Install high-voltage bushing flanges at the upper and lower ends of the high-voltage bushing insulating cylinder respectively. Connect the lower high-voltage bushing flange to the lower equalizing ring and the upper high-voltage bushing flange to the primary terminal block. Connect the upper equalizing ring to the primary terminal block. Insert the conductive rod into the high-voltage bushing insulating cylinder and fasten it to the primary terminal block. S22. Insert the low-pressure air-filled bushing insulation cylinder into the low-pressure air-filled bushing umbrella sleeve, and install the low-pressure air-filled bushing flanges at the upper and lower ends of the low-pressure air-filled bushing insulation cylinder respectively. Connect the sealing plate to the low-pressure air-filled bushing flange, and install the air-filling valve and air-filling port cover on the sealing plate. S23. Insert the core rod into the support umbrella sleeve, and install the support flanges at the upper and lower ends of the core rod to form a support. Fix the eight supports in a circumferential distribution on the base plate. Monitor the assembly progress of the high-pressure bushing unit, the low-pressure gas-filled bushing assembly, and the base frame unit to match their assembly rhythm with that of the main unit, and avoid process delays or stockpiling of semi-finished products.

[0017] It should be further noted that S3 specifically includes the following: S31. Fix the anti-vibration pads on the upper surface of the connecting flange at the preset positions, hoist the unit above the connecting flange, align it with the positioning pins, and slowly lower it onto the anti-vibration pads to connect the bottom flange of the unit to the connecting flange. S32. Hoist the shell above the connecting flange, embed anti-vibration pads between the lower flange of the shell and the top flange of the body unit, lower the shell to fit the connecting flange, and connect the shell to the connecting flange. S33. Connect the lead wire shield and the pressure plate into a combination and install it onto the lower flange of the insulator; Install the conductive base onto the upper flange of the insulator, ensuring that the positions of each component match the docking positions of the lead-out lines and high-voltage bushings of the transformer unit. S34. Hoist the assembled insulator assembly above the upper end cap, align it with the upper end cap through the positioning holes, lower it and connect the insulator to the upper end cap to complete the pre-assembly structure of the upper end cap.

[0018] It should be further explained that S5 specifically includes the following: S1. Hoist the base frame unit to the bottom of the connecting flange, align the mounting holes of the support flange of the base frame unit with the bottom flange of the connecting flange, insert the bolts and pre-tighten them, and tighten them in a diagonal sequence to the specified torque. S52. Clean the flange face of the high-voltage bushing installation interface on the top of the upper end cap, install the metal spiral wound gasket, hoist the high-voltage bushing unit above the interface, and adjust the orientation so that the lower end of the conductive rod is aligned with the conductive seat at the upper end of the insulator. S53. Slowly lower the high-voltage bushing unit so that the conductive rod is inserted into the conductive seat. Continue to lower it until the lower flange of the high-voltage bushing unit is in contact with the upper end cap interface flange. Insert the connecting bolts and tighten them in a symmetrical sequence to the specified torque. S54. Check the torque of the connecting bolts between the high-pressure bushing unit and the upper end cap, confirm that the insertion depth of the conductive rod meets the requirements, and complete the assembly of the closed cavity structure.

[0019] It should be further explained that S6 specifically includes the following: S61. Connect the high vacuum pumping pipeline of the vacuum unit to the inflation port cover interface on the low pressure inflation sleeve assembly through the corrugated pipe. Install the vacuum gauge tube at the connection, close the inflation valve, and check that all valves are in the closed state. S62. Start the vacuum unit's foreboard pump to perform rough evacuation of the cavity. When the vacuum level reaches the preset vacuum level, continue evacuating and continuously monitor the pressure inside the cavity using a vacuum gauge. S63. When the vacuum level drops below the preset vacuum level, close the main valve between the vacuum unit and the cavity, stop pumping, record the pressure value inside the cavity at this time, start timing, maintain for the preset time, and observe the pressure recovery. S64. After the leak test is passed, open the inflation valve and fill the cavity with dry, high-purity insulating gas through the inflation port cover. Adjust the pressure reducing valve to allow the gas to enter slowly until the pressure in the cavity reaches the rated pressure value. Close the inflation valve, let it stand, and measure the pressure again to calculate the daily leakage rate.

[0020] The present invention also provides a grounding reactor, which includes: a body unit, a high-voltage bushing unit, a low-voltage gas-filled bushing assembly, a base frame unit, a connecting flange, a shell, an upper end cap, anti-vibration pads, and an insulator assembly; The body unit is mounted on the connecting flange, the shell covers the outer periphery of the body unit and is fixed to the connecting flange at the lower end, and the upper end cap covers the upper end of the shell; The insulator assembly is installed on the upper end cap, and the connecting rod of the body unit is connected to the lead wire shield. The low-pressure air-filled sleeve assembly is mounted on the connecting flange and communicates with the interior of the housing; The support flange of the base unit is fixedly connected to the bottom of the connecting flange; The high-voltage bushing unit is installed on the upper end cap, and the lower end of the conductive rod of the upper end cap is inserted into the conductive seat of the insulator assembly; The anti-vibration pads are installed between the connecting flange and the body unit, and between the shell and the body unit.

[0021] It should be further noted that the device body unit includes an insulating cylinder, a coil, a heat dissipation shield, a high-voltage shield, an iron core, an iron core clamp, a shielding plate, an insulating plate, and a fixing block; The heat dissipation shield is embedded between the layers of the coil, the coil is wound on the insulating cylinder, and the high voltage shield is fitted around the outer periphery of the coil; the shield and the insulating plate are laid on the surface of the iron core, the iron core is inserted into the coil, the iron core clamps are clamped at both ends of the iron core, and the fixing blocks are installed between the iron core clamps. It should be further noted that the high-voltage bushing assembly includes a high-voltage silicone rubber bushing, a high-voltage insulating cylinder, a high-voltage flange, a lower equalizing ring, a primary terminal block, an upper equalizing ring, and a conductive rod; the high-voltage insulating cylinder is inserted into the high-voltage silicone rubber bushing, the high-voltage flange is fitted onto both ends of the high-voltage insulating cylinder, the lower equalizing ring is connected to the lower high-voltage flange, the primary terminal block is installed on the upper high-voltage flange, the upper equalizing ring is fixed to the primary terminal block, and the conductive rod is inserted into the high-voltage insulating cylinder with one end fixed to the primary terminal block; The low-pressure inflatable sleeve assembly includes a low-pressure silicone rubber sleeve, a low-pressure insulating sleeve, a low-pressure flange, a sealing plate, and an inflation port cover. The low-pressure insulating sleeve is inserted inside the low-pressure silicone rubber sleeve, the low-pressure flange is fitted onto both ends of the low-pressure insulating sleeve, the sealing plate is installed on the low-pressure flange, and the inflation port cover is installed on the sealing plate.

[0022] It should be further noted that the base frame assembly includes a base plate, a support column, a support column umbrella sleeve, a core rod, and a support column flange; the core rod is inserted into the support column umbrella sleeve, and the support column flange is fitted onto both ends of the core rod to form a support column; the eight support columns are distributed in a circular shape and installed on the base plate. The insulator assembly includes an insulator, a pressure plate, a lead wire shield, and a conductive base; the lead wire shield is fitted onto the lower center conductor of the insulator, the pressure plate is pressed against the lead wire shield, the conductive base is installed on the upper center conductor of the insulator, and the insulator is fixed to the upper end cap.

[0023] As can be seen from the above technical solutions, the present invention has the following advantages: In the assembly method of the grounding reactor for DC power systems provided by this invention, the reactor body unit is installed on the connecting flange and enclosed by the shell and the upper end cap to form an inflatable cavity. The insulating gas completely surrounds the reactor body. Combined with the insulating cylinder's skeleton for insulation support, and the shielding plate and the iron core of the insulating plate for isolation insulation from the coil, a multi-layered insulation protection system is constructed. A high-voltage shielding cover is fitted around the coil, and a heat dissipation shielding cover is embedded between the coil layers. With the cooperation of the upper and lower equalizing rings of the high-voltage bushing and the shielding cover of the lower lead wire of the insulator, the electric field distribution can be effectively homogenized, corona discharge and partial discharge can be suppressed, and the reactor can stably withstand the high-voltage conditions of back-to-back DC systems.

[0024] This invention features a heat dissipation shield directly embedded between the coil layers, allowing the heat generated by the coil operation to directly contact the shield, reducing thermal resistance and conducting heat to the external environment. The high-voltage shield, while providing electric field shielding, also assists in dissipating coil heat, resulting in a more uniform temperature distribution throughout the coil and effectively slowing down the aging of the enameled wire insulation.

[0025] Vibration damping blocks are placed between the transformer body and the connecting flange and shell. They can directly absorb the vibration energy generated by the magnetostriction of the iron core and block the transmission of vibration to the shell and base frame. Iron core clamps tighten the iron core laminations, and fixing blocks are installed between the iron core clamps to limit the axial movement and circumferential rotation of the iron core, reduce the vibration amplitude of the iron core, reduce the overall operating noise, and avoid derivative problems such as loose flange bolts and misalignment of sealing surfaces caused by vibration.

[0026] The eight supports of this invention are evenly distributed in a circular pattern on the base plate, ensuring uniform weight distribution and symmetrical force distribution throughout the reactor, thus stably bearing the load of all the upper structures. Each support consists of a core rod and a support sleeve. The core rod bears the mechanical load, while the sleeve provides external insulation, ensuring the mechanical strength of the support and improving its insulation performance. Attached Figure Description

[0027] To more clearly illustrate the technical solution of the present invention, the accompanying drawings used in the description will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 This is a schematic diagram of the assembly of the device body unit of the present invention; Figure 3 This is a schematic diagram of the high-voltage bushing unit assembly of the present invention; Figure 4 This is a schematic diagram of the low-pressure gas-filled sleeve assembly of the present invention; Figure 5 This is a schematic diagram of the assembly of the base unit of the present invention; Figure 6 This is a schematic diagram of the base unit; Figure 7 This is a schematic diagram of insulator assembly.

[0029] Explanation of reference numerals in the attached figures 1-Built body unit, 2-High-voltage bushing unit, 3-Low-voltage gas-filled bushing assembly, 4-Base unit, 5-Connecting flange, 6-Shell, 7-Upper end cap, 8-Insulator, 9-Anti-vibration pad; 101-Insulating cylinder, 102-Coil, 103-Heat insulation shield, 104-High-voltage shield, 105-Core clamp, 106-Core, 107-Shielding plate and insulating plate, 108-Anti-vibration pad; 201-High-voltage bushing umbrella sleeve, 202-High-voltage bushing insulating cylinder, 203- High-voltage bushing flange, 204-lower equalizing ring, 205-primary terminal block, 206-upper equalizing ring, 207-conductive rod; 301-low-voltage gas-filled bushing umbrella sleeve, 302-low-voltage gas-filled bushing insulating cylinder, 303-low-voltage gas-filled bushing flange, 304-sealing plate, 305-gas inlet cover; 401-base plate, 402-support column, 403-support column umbrella sleeve, 404-core body, 405-support column flange; 801-pressure plate, 802-lead wire shield, 803-conductive base. Detailed Implementation

[0030] like Figures 1 to 7 As shown, the grounding reactor involved in this invention includes: a body unit 1, a high-voltage bushing unit 2, a low-voltage gas-filled bushing assembly 3, a base frame unit 4, a connecting flange 5, a housing 6, an upper end cap 7, and an insulator assembly.

[0031] Specifically, the body unit 1 is installed on the connecting flange 5 and located inside the housing 6, so that the body is sealed in the gas filling chamber, and the insulating gas surrounds the body to improve the insulation strength.

[0032] The lower end of the housing 6 is fixed to the connecting flange 5, and the upper end cap 7 is fixed to the upper end of the housing 6; the insulator assembly is installed on the upper end cap 7, and the three together form a sealed pressure vessel that can be filled with insulating gas and also provides mechanical protection.

[0033] The connecting rod of the body unit 1 is connected to the lead wire shield 802; the low-pressure gas-filled sleeve assembly 3 is installed on the connecting flange 5 and communicates with the inside of the shell 6; the support flange 405 of the base unit 4 is fixedly connected to the bottom of the connecting flange 5; the high-pressure sleeve unit 2 is installed on the upper end cap 7.

[0034] Optionally, the high-voltage bushing unit 2 is mounted on the upper end cap 7, allowing the high-voltage side lead wire to pass through the upper end cap into the cavity while maintaining an airtight seal. The lower end of the conductive rod 207 is inserted into the conductive base 803, achieving electrical connection between the high-voltage bushing and the insulator. This insertion method allows for relative displacement during thermal expansion and contraction, preventing stress damage. Alternatively, the insulator assembly can become a conductive component penetrating the upper end cap, leading internal current to the outside while maintaining an airtight seal.

[0035] As can be seen, the connecting flange 5 serves as the connection hub between the transformer body unit and the base frame, shell, and bushing, transmitting loads and sealing gas. The shell 6 encloses the transformer body unit, forming an inflatable cavity to protect internal components and also serves as a grounding terminal. The upper end cap 7 covers the top of the shell, housing insulators and high-voltage bushings, forming a seal at the top of the cavity. The vibration damping pads 9 are placed between the transformer body and the connecting flange and shell to absorb vibration energy and reduce operating noise.

[0036] Furthermore, the device body unit includes an insulating cylinder 101, a coil 102, a heat dissipation shield 103, a high-voltage shield 104, an iron core 106, an iron core clamp 105, a shielding plate and an insulating plate 107, and a fixing block 108. The heat dissipation shield 103 is embedded between the layers of the coil 102, the coil 102 is wound on the insulating cylinder 101, and the high-voltage shield 104 is fitted around the outer periphery of the coil 102; the shielding plate and the insulating plate 107 are laid on the surface of the iron core 106, the iron core 106 is inserted into the coil 102, the iron core clamp 105 is clamped at both ends of the iron core 106, and the fixing block 108 is installed between the iron core clamps 105. It should be noted that: Insulating cylinder 101: Serves as the winding skeleton of coil 102, providing mechanical support and partially insulating the coil from the iron core 106. Coil 102: Formed by winding enameled wire to form an inductor, serving to limit current, filter, or compensate reactive power in the power system. Heat dissipation shield 103: Embedded between coil layers, it conducts heat generated during coil operation and also plays a role in uniformizing the electric field. High-voltage shield 104: Fitted around the coil, forming an equipotential shielding layer, improving the electric field distribution between the coil and ground, and reducing partial discharge. Iron core 106: Constructed from stacked silicon steel sheets, forming a magnetic circuit, enhancing the coil's inductance, and improving reactor efficiency. Iron core clamp 105: Clamps the iron core laminations, making the iron core a single unit, and providing an installation and positioning reference. Shielding plate and insulating plate 107: Lay on the surface of the iron core, shielding leakage flux and reducing stray losses, while also providing the main insulation between the iron core and the coil. Fixing block 108: Installed between the iron core clamps to restrict the axial movement and circumferential rotation of the iron core and enhance structural stability.

[0037] It can be seen that the connection between the heat dissipation shield 103 and the coil 102 layers allows the heat-generating element and the heat sink to be in direct contact, reducing thermal resistance and improving heat dissipation efficiency. At the same time, the interlayer embedding method avoids taking up extra space.

[0038] The connection between the high-voltage shield 104 and the outer periphery of the coil 102 ensures that the coil is in a low electric field region, transferring the high electric field between the shield and the iron core, thereby suppressing corona and partial discharge.

[0039] The connection relationship between the shielding plate and the insulating plate 107 laid on the surface of the iron core 106 and the coil 102 is ensured to ensure that the shielding layer is in close contact with the iron core, effectively guide the leakage flux, reduce additional losses, and at the same time, the position of the insulating plate is fixed to avoid displacement during installation, which would result in insufficient insulation distance.

[0040] The iron core clamp 105 clamps the iron core 106 and the fixing block 108 is installed between the clamps, making the iron core a rigid whole. The multiple fixing blocks restrict the axial and circumferential degrees of freedom respectively, effectively resisting the vibration caused by magnetostriction.

[0041] Furthermore, the high-voltage bushing assembly includes a high-voltage silicone rubber bushing 201, a high-voltage insulating cylinder 202, a high-voltage flange 203, a lower equalizing ring 204, a primary terminal block 205, an upper equalizing ring 206, and a conductive rod 207.

[0042] The high-voltage insulating cylinder 202 is inserted inside the high-voltage silicone rubber sleeve 201, and the two are tightly fitted together. The silicone oil lubrication fills the micro gaps, eliminates air gaps, and improves the surface flashover voltage.

[0043] High-voltage flange 203 is fitted at both ends of high-voltage insulating cylinder 202. Optionally, the flange can be clamped with bolts to form a reliable electrical contact and mechanical connection with the end of the insulating cylinder. At the same time, it serves as the end electrode of the capacitor core, making the electric field distribution more uniform.

[0044] The lower equalizing ring 204 is connected to the lower high-pressure flange 203, the primary terminal block 205 is installed on the upper high-pressure flange 203, and the upper equalizing ring 206 is fixed to the primary terminal block 205. The conductive rod 207 is inserted inside the high-voltage insulating cylinder 202 and one end is fixed to the primary terminal block 205, ensuring a reliable connection of the current-carrying path. The bolt fixing method facilitates disassembly and maintenance.

[0045] It should be noted that the high-voltage silicone rubber bushing 201 serves as the external insulation component for the high-voltage side lead-out line, protecting the internal conductive components from environmental corrosion. The high-voltage insulating cylinder 202 is housed inside the high-voltage silicone rubber bushing, providing primary insulation from the high voltage to ground and supporting the internal conductive rod. The high-voltage flange 203 clamps both ends of the high-voltage insulating cylinder, serving as an installation interface and simultaneously forming the end electrodes of the capacitor core. The lower equalizing ring 204 is mounted on the lower flange, uniformizing the electric field at the lower end of the bushing to prevent corona discharge. The primary terminal block 205 serves as the high-voltage side terminal, connecting to external lines and simultaneously fixing the upper equalizing ring and the conductive rod. The upper equalizing ring 206 is mounted on the primary terminal block, uniformizing the electric field at the upper end of the bushing and increasing the corona initiation voltage. The conductive rod 207 passes through the high-voltage insulating cylinder, transmitting high-voltage current, and its lower end connects to the conductive seat on the insulator.

[0046] Furthermore, the low-pressure inflatable sleeve assembly includes a low-pressure silicone rubber sleeve 301, a low-pressure insulating sleeve 302, a low-pressure flange 303, a sealing plate 304, and an inflation port cover plate 305.

[0047] The low-pressure insulating sleeve 302 is inserted inside the low-pressure silicone rubber sleeve 301, forming a double insulation structure to improve reliability. The low-pressure flange 303 is fitted onto both ends of the low-pressure insulating sleeve 302, and the sealing plate 304 is installed on the low-pressure flange 303, forming a static seal with O-rings to close the ends of the low-pressure sleeve, making the entire cavity an inflatable, airtight system. The inflation port cover 305 is installed on the sealing plate 304. It is normally sealed, but can be opened when needed to perform inflation, vacuuming, and gas sampling.

[0048] As can be seen, the low-voltage silicone rubber sleeve 301 serves as the external insulation component for the low-voltage side lead-out line, protecting the internal structure. The low-voltage insulating sleeve 302 is installed inside the low-voltage silicone rubber sleeve, providing low-voltage insulation to ground. The low-voltage flange 303 clamps both ends of the low-voltage insulating sleeve, serving as an installation interface for connecting the sealing plate. The sealing plate 304 seals the end of the low-voltage sleeve, forming an air chamber, and also provides an inflation port. The inflation port cover 305 is installed on the sealing plate, normally sealing the air chamber, and opening it during inflation or sampling.

[0049] Furthermore, the base frame assembly includes a base plate 401, a support column 402, a support column umbrella cover 403, a core rod 404, and a support column flange 405.

[0050] The core rod 404 is inserted into the support umbrella sleeve 403, and the support flange 405 is fitted on both ends of the core rod 404 to form the support 402. The eight supports 402 are distributed in a circular shape and installed on the base plate 401.

[0051] It should be noted that the base plate 401 serves as the foundation of the base frame assembly, bearing the weight of the entire reactor and connecting the support column. The support column 402 consists of a core rod and a shed, supporting the connecting flange and the upper structure, and providing insulation distance. The support column shed 403: wraps around the core rod, providing external insulation and creepage distance, protecting the core rod. The core rod 404 bears the gravitational load of the reactor. The fixed connection between the support flange 405 and the bottom of the connecting flange 5 of the base frame assembly allows the weight of the entire reactor to be transferred to the base frame through the connecting flange, and then from the base frame to the foundation.

[0052] The connection between the core rod 404, which passes through the support umbrella sleeve 403 and has support flanges 405 fitted at both ends, separates the mechanical load-bearing component, the core rod, from the outer insulating component, the umbrella sleeve. The core rod bears the load, while the umbrella sleeve provides insulation; each performs its specific function, improving reliability. The connection between the eight supports 402, which are arranged in a circumferential pattern on the base plate 401, ensures even load distribution and symmetrical force distribution, improving overall stability.

[0053] Furthermore, the insulator assembly includes an insulator 8, a pressure plate 801, a lead wire shield 802, and a conductive base 803. The lead wire shield 802 is sleeved on the lower center conductor of the insulator 8, the pressure plate 801 is pressed against the lead wire shield 802, the conductive base 803 is installed on the upper center conductor of the insulator 8, and the insulator 8 is fixed to the upper end cap 7. It should be noted that insulator 8 is mounted on the upper end cap, supporting the lead wire shield and conductive base, and providing insulation to ground. Pressure plate 801 presses the lead wire shield tightly, maintaining reliable electrical connection. Lead wire shield 802 is fitted onto the lower end of the insulator, connecting the connecting rod extending from the transformer body, and simultaneously improving the electric field at that location. Conductive base 803 is mounted on the upper end of the insulator, receiving the conductive rod from the high-voltage bushing and transmitting current. The connection between the connecting rod extending from the transformer body unit and the lead wire shield 802 enables the transmission of current from inside the transformer body to the insulator.

[0054] The following describes in detail the method for assembling a grounding reactor for a DC power system according to this application. Specific details, such as particular system structures and technologies, are presented for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of this application. However, those skilled in the art will understand that this application can also be implemented in other embodiments without these specific details.

[0055] It should be understood that, when used in this specification, the term "comprising" indicates the presence of the described feature, integral, step, operation, element, and / or component, but does not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components, and / or collections thereof. The terms "comprising," "including," "having," and variations thereof all mean "including but not limited to," unless otherwise specifically emphasized.

[0056] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0057] Please see Figure 1 The diagram shows a flowchart of a grounding reactor assembly method for a DC power system in a specific embodiment. The method includes: S1. By winding the coil, installing the shielding cover and stacking the iron core, the assembly of the body unit 1 is completed and the performance of the semi-finished product is verified.

[0058] S2. Separately and independently assemble the high-pressure bushing unit 2, which includes conductive and equalizing structures, the low-pressure inflatable bushing assembly 3, which has an inflation function, and the base frame unit 4 for support.

[0059] S3. The pre-installed body unit 1 is positioned and installed inside the housing 6 using the anti-vibration pad 9, and the insulator 8 with lead wire shield 802 and conductive seat 803 is pre-installed on the upper end cap 7.

[0060] S4. Fix the upper end cap 7 to the shell 6, and install the pre-installed low-pressure air-filled sleeve assembly 3 in step S2 onto the corresponding interface of the connecting flange 5.

[0061] In some embodiments, before the upper end cap 7 is connected to the housing 6, a sealing strip is embedded and firmly adhered in the sealing groove of the upper flange of the housing 6.

[0062] Furthermore, during the closing process, four long guide rods are inserted into the corresponding holes of the flange to guide the upper end cap 7 to fall smoothly and prevent the sealing ring from being cut.

[0063] Furthermore, when the distance between the upper end cap 7 and the flange face of the housing 6 reaches a certain distance, the descent is paused. The operator enters through the manhole on the side of the housing 6 and locates the braided copper strip flexible connection leading out from the top of the body unit 1. Using a specially made long-handled socket wrench, the terminal of the flexible connection is securely connected to the terminal block at the lower end of the lead wire shield 802, and the connection is checked with a torque wrench.

[0064] After the flange is closed, insert four bolts symmetrically around the flange and pre-tighten them, then remove the lifting slings. Install all bolts and use the intelligent torque control system to apply the torque in three stages, from the center outwards in a diagonal pattern, until the final torque value is reached. After each torque application, use a feeler gauge to check the uniformity of the flange clearance.

[0065] For the installation of the low-pressure air-filled sleeve assembly 3, first align its interface flange with the interface on the side of the connecting flange 5, then place the sealing ring in the sealing groove, and first fix it by hand by pushing in the positioning pin. Then tighten the bolts step by step from the bottom and the side.

[0066] S5. Connect the bottom of the base frame unit 4 to the bottom of the connecting flange 5 to form an overall support, and then install the pre-installed high-pressure bushing unit 2 to the top interface of the upper end cap 7 to form a closed cavity structure.

[0067] S6. Perform vacuuming on the entire product cavity after final assembly, and fill it with insulating gas after the vacuum requirement is met, and conduct a sealing test to ensure the airtightness of the product.

[0068] S7. Conduct routine whole-machine tests and gas composition analysis on products that have passed the airtightness test to fully verify whether the electrical performance and internal gas state meet the factory standards.

[0069] In some embodiments, equipment debugging and wiring before testing can eliminate equipment errors. Copper test wires have excellent conductivity, which can reduce signal loss during testing and ensure accurate test data.

[0070] The grounding terminal connected to the base plate 401 can form a complete test circuit. The sealed sampling tube can prevent the leakage of insulating gas and the mixing of outside air during the sampling process, ensuring the purity of the gas sample.

[0071] The DC resistance test in this embodiment can reflect the conduction performance and connection reliability of the coil 102, and the insulation resistance test can reflect the insulation performance between the insulating cylinder 101, the coil 102 and the iron core 106. If the resistance value is too low, it indicates that there are problems such as damage or moisture in the insulating components.

[0072] Furthermore, partial discharge testing can reflect the uniformity of the electric field of high-voltage bushing unit 2 and insulator 8. Excessive discharge indicates that there are defects in the voltage equalization structure or insulation components.

[0073] Excitation characteristic test can reflect the magnetic permeability and saturation characteristics of iron core 106, and judge the stacking quality of iron core and the shielding effect of shielding plate 107.

[0074] In gas composition analysis, the purity of insulating gas directly affects the insulation performance of the product. Insufficient purity will lead to a decrease in insulation strength, while excessive moisture content will corrode the metal parts of the unit 1 and reduce the insulation performance of the insulating material. The gas analyzer can accurately identify the gas composition and content through a specific detection module, realize quantitative detection, and ensure that the gas state meets the operating requirements.

[0075] In some specific embodiments, step S1 specifically includes the following execution methods: S11. On the insulating cylinder 101, enameled wire is wound in a rectangular spiral along the axial direction to form a coil 102; During the winding process, three layers of mutually insulated annular heat dissipation shields 103 are sequentially embedded at the preset radial interlayer positions of the coil 102. After the winding and shield 103 embedding process is completed, the insulating cylinder 101 with the coil 102 and heat dissipation shield 103 is placed in an oven for curing treatment.

[0076] In some embodiments, the operation uses an insulating cylinder 101 as the skeleton and main insulation, and the enameled wire is tightly and regularly wound in a rectangular spiral on its surface to directly form each turn of the coil 102.

[0077] Optionally, the winding is not completed in one go, but is paused when the total thickness is 1 / 4, 1 / 2, and 3 / 4, and the annular heat dissipation shield 103 is then fitted in. Each heat dissipation shield 103 is padded with insulating material between itself and the adjacent wire turns.

[0078] S12. The cylindrical high-voltage shield 104 is axially fitted onto the outside of the coil 102 that has been cured, ensuring that there is a uniform insulation gap between the inner wall of the high-voltage shield 104 and the outermost turns of the coil 102.

[0079] S13. Position and place the laminated iron core 106 on one side and its corresponding iron core clamp 105; place a set of shielding plate and insulating plate 107 composed of conductive shielding plate and insulating material plate tightly against the end face of iron core 106; and fit the coil module assembled in step S12 along the core column axis of iron core 106.

[0080] In some embodiments, a pre-assembled U-shaped laminated iron core 106 and its matching steel structure clamp 105 are placed on an assembly platform. An insulating plate facing the iron core 106 and a conductive shielding plate facing away from the iron core 106 are attached to the end face of that side of the iron core 106. The coil module, already fitted with the high-voltage shield 104, is lifted, its axis aligned with the core column axis of the iron core 106, and then smoothly lowered axially, allowing the core column of the iron core 106 to pass through the central hole of the coil 102 and the insulating cylinder 101. This ensures the coincidence of the magnetic field axis, the coil axis, and the iron core column axis, resulting in a symmetrical magnetic circuit and performance meeting design expectations.

[0081] S14. On the other side opposite to step S13, first place another set of shielding plates and insulating plates 107, and then connect the other side of the laminated iron core 106 with the iron core part that has been initially assembled to form a closed magnetic circuit. Further, install the other side core clamp 105 and use studs and nuts passing through the clamp 105 and the laminated core 106 for initial fastening; finally, install multiple sets of rigid fixing blocks 108 between the corresponding positions of the two core clamps 105, apply axial and circumferential constraint forces respectively, and complete the mechanical locking of the body unit 1.

[0082] S15. Apply a preset AC test voltage to the assembled and locked unit 1, and measure the excitation characteristic curve; measure the impedance error under the specified current to verify whether the electrical performance meets the preset parameters.

[0083] In some embodiments, the axial fixing block 108 bears and transmits the axial pulsating force generated by the magnetization of the iron core 106, preventing the force from being entirely borne by the friction between the silicon steel laminations or the insulating varnish film, which could lead to loosening of the iron core 106 and increased noise. This ensures that the air gap at the mating surface of the iron core 106 will not increase due to loosening after operation, thereby maintaining the stability of the reactor's electrical parameters.

[0084] In some specific embodiments, step S2 specifically includes the following execution methods: S21. Slide the high-voltage bushing insulating cylinder 202 into the high-voltage bushing umbrella sleeve 201. Install high-voltage bushing flanges 203 on the upper and lower ends of the high-voltage bushing insulating cylinder 202 respectively. Connect the lower high-voltage bushing flange 203 to the lower equalizing ring 204 and the upper high-voltage bushing flange 203 to the primary terminal block 205. Connect the upper equalizing ring 206 to the primary terminal block 205. Insert the conductive rod 207 into the high-voltage bushing insulating cylinder 202 and fasten it to the primary terminal block 205.

[0085] In some embodiments, the high-voltage silicone rubber umbrella sleeve 201 provides external insulation to adapt to damp and dirty outdoor environments. The epoxy fiberglass cloth insulating cylinder 202 provides internal insulation, isolating the conductive rod from the external structure. The upper and lower equalizing rings equalize the electric field distribution at the flange, preventing electric field concentration from causing partial discharge. The conductive rod 207 serves as a high-voltage current conduction path, ensuring reliable electrical connections.

[0086] S22. Insert the low-pressure air-filled sleeve insulating cylinder 302 into the low-pressure air-filled sleeve umbrella 301. Install the low-pressure air-filled sleeve flange 303 on the upper and lower ends of the low-pressure air-filled sleeve insulating cylinder 302 respectively. Connect the sealing plate 304 to the low-pressure air-filled sleeve flange 303. Install the air-filled valve and the air-filled port cover plate 305 on the sealing plate 304.

[0087] S23. Insert the core rod 404 into the support umbrella sleeve 403, and install the support flange 405 on the upper and lower ends of the core rod 404 to form the support 402. Fix the eight supports 402 in a circumferential distribution on the base plate 401.

[0088] S24. Control the assembly progress of the high-pressure bushing unit 2, the low-pressure gas-filled bushing assembly 3 and the base frame unit 4 to match the assembly rhythm of the body unit 1, and avoid process waiting or semi-finished product backlog.

[0089] In some specific embodiments, step S3 specifically includes the following execution methods: S31. Fix the anti-vibration pad 9 on the upper surface of the connecting flange 5 at the preset position, hoist the body unit 1 above the connecting flange 5, align it with the positioning pin, and slowly lower it onto the anti-vibration pad 9. Use bolts to fasten the bottom flange of the body unit 1 to the connecting flange 5.

[0090] In some embodiments, the shock-absorbing pad 9 has good damping performance, which can absorb the vibration generated during the operation of the body unit 1 and prevent the vibration from being transmitted to the connecting flange 5 and the housing 6. The locating pin ensures the coaxiality of the body unit 1 and the connecting flange 5 and avoids magnetic field distortion caused by eccentricity.

[0091] S32. Hoist the shell 6 above the connecting flange 5, insert the anti-vibration pad 9 between the lower flange of the shell 6 and the top flange of the body unit 1, slowly lower the shell 6 so that it fits against the connecting flange 5, and use bolts to fasten the shell 6 to the connecting flange 5.

[0092] In some embodiments, the housing 6 serves as an external protective structure for the body unit 1, preventing external contamination and mechanical damage. The shock-absorbing pads 9 isolate vibration transmission between the housing 6 and the body unit 1, preventing resonance of the housing 6.

[0093] S33. Fasten the lead wire shield 802 and the pressure plate 801 together with bolts to form an assembly and install it on the lower flange of the insulator 8; then install the conductive seat 803 on the upper flange of the insulator 8 with bolts to ensure that the position of each component matches the docking position of the lead wire and high voltage bushing of the transformer unit 1.

[0094] In some embodiments, the lead shield 802 can homogenize the electric field distribution of the leads of the body unit 1, preventing partial discharge caused by electric field concentration. The pressure plate 801 serves as an insulating support, isolating the lead shield 802 from the metal components of the insulator 8. The conductive seat 803 serves as the mating end of the conductive rod 207 of the high-voltage bushing unit 2, ensuring reliable electrical connection. Coaxiality control ensures that the conductive rod 207 is inserted without obstruction.

[0095] S34. Hoist the assembled insulator 8 assembly above the upper head 7, align it with the upper head 7 through the positioning hole, slowly lower it, and then use bolts to fasten the insulator 8 to the upper head 7 to complete the pre-assembly structure on the upper head side.

[0096] In some embodiments, the upper end cap 7 serves as the top structure of the product and, after being connected to the insulator 8 assembly, forms a high-voltage lead-out structure. The locating pin ensures the coaxiality of the insulator 8 and the upper end cap 7, guaranteeing the installation accuracy of the high-voltage bushing unit 2.

[0097] In some specific embodiments, step S5 specifically includes the following execution method: S51. Hoist the base frame unit 4 to the bottom of the connecting flange 5, align the support flange 405 of the base frame unit 4 with the mounting hole of the bottom flange of the connecting flange 5, insert the bolts and pre-tighten them, and tighten them in a diagonal sequence to the specified torque.

[0098] In some embodiments, the base unit 4 consists of eight supports 402 and a base plate 401, with support flanges 405 welded to the top of the supports.

[0099] Next, use slings to connect the lifting lugs on the base plate 401 and lift the base frame unit 4 to below the connecting flange 5. Use a spirit level to measure the upper plane of the support flange 405 and adjust the sling length to keep the base frame unit 4 level. Slowly lift the base frame unit 4 so that the support flange 405 gradually approaches the bottom flange of the connecting flange 5.

[0100] When the distance between the two flanges meets the requirements, use the fine-tuning base unit 4 to align the bolt holes on the support flange 405 with the threaded holes on the bottom flange of the connecting flange 5.

[0101] Insert four guide rods into the bolt holes, then continue lifting until the two flanges are flush. Insert bolts through the holes outside the guide rods, fit flat washers and spring washers, and tighten the nuts. Remove the guide rods and insert the remaining bolts into the empty holes. Tighten in three stages diagonally using a torque wrench.

[0102] S52. Clean the flange face of the high-voltage bushing installation interface on the top of the upper end cap 7, install the metal spiral wound gasket, hoist the high-voltage bushing unit 2 above the interface, and adjust the orientation so that the lower end of the conductive rod 207 is aligned with the conductive seat 803 at the upper end of the insulator 8.

[0103] S53. Slowly lower the high-pressure bushing unit 2 so that the conductive rod 207 is inserted into the conductive seat 803. Continue to lower until the lower flange 203 of the high-pressure bushing unit 2 is in contact with the interface flange of the upper end cap 7. Insert the connecting bolts and tighten them in a symmetrical sequence to the specified torque.

[0104] S54. Check the torque of the connecting bolts between the high-pressure bushing unit 2 and the upper end cap 7, confirm that the insertion depth of the conductive rod 207 meets the requirements, and complete the assembly of the closed cavity structure.

[0105] In some specific embodiments, step S6 specifically includes the following execution method: S61. Connect the high vacuum pumping pipeline of the vacuum unit to the inflation port cover plate 305 interface on the low pressure inflation sleeve assembly 3 through the corrugated pipe. Install the vacuum gauge tube at the connection, close the inflation valve, and check that all valves are in the closed state.

[0106] S62. Start the vacuum unit's foreboard pump to perform rough evacuation of the cavity. When the vacuum level reaches 100Pa, turn on the Roots pump and diffusion pump to continue evacuating the vacuum. Continuously monitor the pressure inside the cavity using a vacuum gauge.

[0107] S63. When the vacuum level drops below 10Pa, close the main valve between the vacuum unit and the chamber, stop pumping, record the pressure value inside the chamber at this time, start timing, maintain this state for at least four hours, record the pressure value every 30 minutes during this period, and observe the pressure recovery.

[0108] S64. In the later stage of the maintenance phase, a helium mass spectrometer leak detector is used to check for leaks at all sealing surfaces, welds, and bolt connections of the connecting flange 5, upper head 7, shell 6, low-pressure gas-filled sleeve assembly 3, and high-pressure sleeve unit 2, and the leakage rate at each location is recorded.

[0109] S65. After the leak test is passed, open the inflation valve and fill the cavity with dry, high-purity insulating gas through the inflation port cover 305. Adjust the pressure reducing valve to allow the gas to enter slowly until the pressure in the cavity reaches the rated pressure value. Close the inflation valve and let it stand for 24 hours before measuring the pressure again and calculating the daily leakage rate.

[0110] In some embodiments, a vacuum unit is used to perform multi-stage evacuation of the cavity, drawing the gas inside to a high vacuum state and creating a large pressure difference between the inside and outside of the cavity, making even minor leaks easier to detect. After closing the main valve and holding the pressure for a period of time, the overall sealing level of the cavity is initially assessed by observing the rate of pressure recovery. A helium mass spectrometer leak detector is used to precisely inspect key sealing components such as flanges, end caps, shells, sleeves, welds, and bolts, quantitatively measuring the leakage rate. After passing the leak test, dry, high-purity insulating gas is introduced into the cavity to the rated pressure, and the cavity is left to stand at atmospheric pressure / pressurized for 24 hours. The pressure is then measured again, and the daily leakage rate is calculated, completing the full sealing verification from vacuum to positive pressure.

[0111] It should be understood that the sequence number of each step in the above embodiments does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention.

Claims

1. A method for assembling a grounding reactor for a DC power system, characterized in that, Includes the following steps: S1. By winding the coil, installing the shield and stacking the iron core, the assembly of the body unit (1) is completed and the performance of the semi-finished product is verified. S2. Assemble the high-pressure bushing unit (2) containing conductive and equalizing structures, the low-pressure inflatable bushing assembly (3) and the base frame unit (4) for support respectively. S3. The pre-installed body unit (1) is positioned and installed in the housing (6) using anti-vibration pads (9), and the insulator (8) with lead wire shield (802) and conductive seat (803) is pre-installed on the upper end cap (7); S4. Fix the upper end cap (7) to the shell (6) and install the pre-installed low-pressure gas sleeve assembly (3) onto the corresponding interface of the connecting flange (5); S5. Connect the bottom of the base frame unit (4) to the bottom of the connecting flange (5) to form an overall support, and then install the pre-installed high-pressure bushing unit (2) to the top interface of the upper end cap (7) to form a closed cavity structure. S6. Perform vacuuming on the enclosed cavity structure, and after the vacuum requirement is met, fill it with insulating gas and perform a sealing test. S7. After passing the airtightness test, conduct routine whole-machine tests and gas composition analysis to verify whether the electrical performance and gas state meet the requirements.

2. The method for assembling a grounding reactor for a DC power system according to claim 1, characterized in that, S1 specifically includes the following: S11. On the insulating cylinder (101), enameled wire is wound in a rectangular spiral along the axial direction to form a coil (102). During the winding process, three mutually insulated annular heat dissipation shields (103) are embedded at the preset radial interlayer position of the coil (102); after the winding and shield (103) embedding process is completed, the insulating cylinder (101) with the coil (102) and heat dissipation shield (103) is placed in an oven for curing treatment. S12. The cylindrical high-voltage shield (104) is fitted axially onto the outside of the coil (102) that has been cured, ensuring that there is a uniform insulation gap between the inner wall of the high-voltage shield (104) and the outermost turns of the coil (102). S13. Position and place the laminated iron core (106) on one side and its corresponding iron core clamp (105); place the shielding plate and the insulating plate (107) composed of conductive shielding plate and insulating material plate tightly against the end face of the side iron core (106); and fit the coil module assembled in step S12 along the core column axis of the iron core (106). S14. On the other side opposite to step S13, place another set of shielding plates and insulating plates, and then connect the other side of the laminated iron core (106) with the iron core part that has been initially assembled to form a closed magnetic circuit. S15. Apply a preset AC test voltage to the assembled and locked unit (1) and measure the excitation characteristic curve; measure the impedance error under the specified current to verify whether the electrical performance meets the preset parameters.

3. The method for assembling a grounding reactor for a DC power system according to claim 1, characterized in that, S2 specifically includes the following: S21. Slide the high-voltage bushing insulating cylinder (202) into the high-voltage bushing umbrella sleeve (201). Install high-voltage bushing flanges (203) on the upper and lower ends of the high-voltage bushing insulating cylinder (202). Connect the lower high-voltage bushing flange (203) to the lower equalizing ring (204). Connect the upper high-voltage bushing flange (203) to the primary terminal block (205). Connect the upper equalizing ring (206) to the primary terminal block (205). Insert the conductive rod (207) into the high-voltage bushing insulating cylinder (202) and connect it to the primary terminal block (205). S22. Insert the low-pressure air-filled bushing insulation cylinder (302) into the low-pressure air-filled bushing umbrella sleeve (301), and install the low-pressure air-filled bushing flange (303) on the upper and lower ends of the low-pressure air-filled bushing insulation cylinder (302). Connect the sealing plate (304) on the low-pressure air-filled bushing flange (303), and install the air-filled valve and air-filled port cover plate (305) on the sealing plate (304). S23. Insert the core rod (404) into the support umbrella sleeve (403), and install the support flange (405) on the upper and lower ends of the core rod (404) to form the support (402). Fix the eight supports (402) on the base plate (401) in a circumferential distribution.

4. The method for assembling a grounding reactor for a DC power system according to claim 1, characterized in that, S3 specifically includes the following: S31. Fix the anti-vibration pad (9) on the upper surface of the connecting flange (5) at the preset position, hoist the body unit (1) above the connecting flange (5), align it with the positioning pin and slowly lower it onto the anti-vibration pad (9), and connect the bottom flange of the body unit (1) to the connecting flange (5). S32. Hoist the shell (6) above the connecting flange (5), insert the anti-vibration pad (9) between the lower flange of the shell (6) and the top flange of the body unit (1), and fit the lower shell (6) with the connecting flange (5) to connect the shell (6) and the connecting flange (5). S33. Connect the lead wire shield (802) and the pressure plate (801) into a combination and install it on the lower flange of the insulator (8); Install the conductive base (803) onto the upper flange of the insulator (8) to ensure that the positions of each component match the docking positions of the lead wires and high-voltage bushings of the transformer unit (1); S34. Hoist the assembled insulator (8) assembly above the upper end cap (7), align it with the upper end cap (7) through the positioning hole, and then lower it to connect the insulator (8) to the upper end cap (7) to complete the pre-assembly structure on the upper end cap side.

5. The method for assembling a grounding reactor for a DC power system according to claim 1, characterized in that, S5 specifically includes the following: S51. Hoist the base frame unit (4) to the bottom of the connecting flange (5), adjust the mounting holes of the support flange (405) of the base frame unit (4) and the bottom flange of the connecting flange (5) to be aligned, insert the bolts and pre-tighten them, and tighten them in a diagonal sequence to the specified torque. S52. Clean the flange face of the high-voltage bushing installation interface on the top of the upper end cap (7), install the metal spiral wound gasket, hoist the high-voltage bushing unit (2) above the interface, and adjust the orientation so that the lower end of the conductive rod (207) is aligned with the conductive seat (803) at the upper end of the insulator (8); S53. Lower the height of the high-pressure bushing unit (2) so that the conductive rod (207) is inserted into the conductive seat (803). Continue to lower until the lower flange (203) of the high-pressure bushing unit (2) is in contact with the interface flange of the upper end cap (7). Insert the connecting bolts and tighten them in a symmetrical sequence to the specified torque. S54. Check the torque of the connecting bolts between the high-pressure bushing unit (2) and the upper end cap (7), confirm that the insertion depth of the conductive rod (207) meets the requirements, and complete the assembly of the closed cavity structure.

6. The method for assembling a grounding reactor for a DC power system according to claim 1, characterized in that, S6 specifically includes the following: S61. Connect the high vacuum pumping pipeline of the vacuum unit to the air inlet cover plate (305) interface on the low pressure air inlet sleeve assembly (3) through the corrugated pipe. Install the vacuum gauge tube at the connection, close the air inlet valve, and check that all valves are closed. S62. Start the vacuum unit's foreboard pump to perform rough evacuation of the cavity. When the vacuum level reaches the preset vacuum level, continue evacuating and continuously monitor the pressure inside the cavity using a vacuum gauge. S63. When the vacuum level drops below the preset vacuum level, close the main valve between the vacuum unit and the cavity, stop pumping, record the pressure value inside the cavity at this time, start timing, maintain for the preset time, and observe the pressure recovery. S64. After the leak test is passed, open the inflation valve and fill the cavity with dry, high-purity insulating gas through the inflation port cover (305). Adjust the pressure reducing valve to allow the gas to enter slowly until the pressure in the cavity reaches the rated pressure value. Close the inflation valve, let it stand, and measure the pressure again to calculate the daily leakage rate.

7. A grounding reactor, characterized in that, The grounding reactor is assembled according to the grounding reactor assembly method for DC power systems according to any one of claims 1 to 6. The grounding reactor includes: a body unit (1), a high-voltage bushing unit (2), a low-voltage gas-filled bushing assembly (3), a base frame unit (4), a connecting flange (5), a shell (6), an upper end cap (7), a shock-absorbing pad (9), and an insulator assembly. The body unit (1) is installed on the connecting flange (5), the shell (6) covers the outer periphery of the body unit (1), and the lower end is fixed to the connecting flange (5). The upper end cap (7) covers the upper end of the shell (6). The insulator assembly is installed on the upper end cap (7), and the connecting rod of the body unit (1) is connected to the lead wire shield (802); The low-pressure air-filled sleeve assembly (3) is installed on the connecting flange (5) and communicates with the inside of the housing (6); The support flange (405) of the base unit (4) is fixedly connected to the bottom of the connecting flange (5); The high-voltage bushing unit (2) is installed on the upper end cap (7), and the lower end of the conductive rod (207) of the upper end cap (7) is inserted into the conductive seat (803) of the insulator assembly; The shock-absorbing pad (9) is placed between the shell (6) and the body unit.

8. The grounding reactor according to claim 7, characterized in that, The main unit includes an insulating cylinder (101), a coil (102), a heat dissipation shield (103), a high voltage shield (104), an iron core (106), an iron core clamp (105), a shielding plate and an insulating plate (107), and a fixing block (108). A heat dissipation shield (103) is embedded between the layers of the coil (102), the coil (102) is wound on the insulating cylinder (101), and a high voltage shield (104) is fitted around the outer periphery of the coil (102); a shielding plate and an insulating plate (107) are laid on the surface of the iron core (106), the iron core (106) is inserted into the coil (102), the iron core clamp (105) is clamped at both ends of the iron core (106), and a fixing block (108) is installed between the iron core clamp (105).

9. The grounding reactor according to claim 7, characterized in that, The high-voltage bushing assembly includes a high-voltage silicone rubber bushing (201), a high-voltage insulating cylinder (202), a high-voltage flange (203), a lower equalizing ring (204), a primary terminal block (205), an upper equalizing ring (206), and a conductive rod (207). The high-voltage insulating cylinder (202) is installed inside the high-voltage silicone rubber sleeve (201), the high-voltage flange (203) is fitted on both ends of the high-voltage insulating cylinder (202), the lower equalizing ring (204) is connected to the lower high-voltage flange (203), the primary terminal block (205) is installed on the upper high-voltage flange (203), the upper equalizing ring (206) is fixed on the primary terminal block (205), and the conductive rod (207) is installed inside the high-voltage insulating cylinder (202) with one end fixed to the primary terminal block (205); The low-pressure inflatable sleeve assembly includes a low-pressure silicone rubber sleeve (301), a low-pressure insulating sleeve (302), a low-pressure flange (303), a sealing plate (304), and an inflation port cover plate (305). The low-pressure insulating sleeve (302) is inserted inside the low-pressure silicone rubber sleeve (301), the low-pressure flange (303) is fitted on both ends of the low-pressure insulating sleeve (302), the sealing plate (304) is installed on the low-pressure flange (303), and the air inlet cover plate (305) is installed on the sealing plate (304).

10. The grounding reactor according to claim 7, characterized in that, The underframe assembly includes a base plate (401), a support column (402), a support column umbrella cover (403), a core rod (404), and a support column flange (405). The core rod (404) is inserted into the support umbrella sleeve (403), and the support flange (405) is fitted on both ends of the core rod (404) to form the support (402). The eight supports (402) are arranged in a circular shape and installed on the base plate (401). The insulator assembly includes an insulator (8), a pressure plate (801), a lead wire shield (802), and a conductive seat (803); the lead wire shield (802) is sleeved on the lower center conductor of the insulator (8), the pressure plate (801) is pressed on the lead wire shield (802), the conductive seat (803) is installed on the upper center conductor of the insulator (8), and the insulator (8) is fixed on the upper end cap (7).

Images