A high-impedance three-phase combined large power transformer with a built-in integrated reactor three-phase centralized overall arrangement.

Abstract

This invention discloses a high-impedance three-phase combined large power transformer with a three-phase centralized integrated arrangement of built-in reactors. It relates to the field of large power transformer technology and includes A, B, and C phase transformer bodies, bellows, an oil-cooling system, a reactor system, winding assemblies, clamping assemblies, and a current-disrupting assembly. The reactor system is independently arranged on the C-phase side, with zinc oxide surge arresters connected in parallel across its coils to clamp lightning overvoltages. The winding assembly has clamping assemblies within the spacers; a drive rod drives the top block to compact the winding coils, which are then locked by a check valve to prevent loosening due to thermal expansion and contraction. A current-disrupting assembly is located on the outside of the insulation sleeve; an electric push rod drives the current-disrupting plates to move up and down reciprocally, accelerating the flow of cooling oil. This invention achieves a compact arrangement of the high-impedance transformer, effectively suppresses overvoltages, prevents winding loosening, improves heat dissipation efficiency, and ensures reliable operation.

Description

Technical Field

[0001] This invention relates to the field of large power transformer technology, specifically a three-phase combined large power transformer with a high impedance achieved by a three-phase centralized overall arrangement of built-in attached reactors. Background Technology

[0002] As a core component of the power system, the short-circuit impedance of the power transformer directly affects the short-circuit current level of the power grid and the stability of system operation. In large-capacity transmission and distribution systems, it is usually necessary to increase the short-circuit impedance of the transformer to limit the short-circuit current and improve the system's shock resistance.

[0003] In existing technologies, methods to improve short-circuit impedance mainly include: optimizing winding structure parameters (such as increasing leakage flux paths, adjusting winding spacing, etc.), or connecting reactors in series in the transformer circuit. Among these, achieving high impedance through reactor configuration has advantages such as flexible adjustment and significant effects, and has been widely used.

[0004] However, the existing solutions still have the following shortcomings: 1. Reactors are usually arranged independently in separate phases or externally, resulting in a large overall space occupation, which is not conducive to the compact design of large transformers; the connection path between the reactor and the transformer winding is long and complex, and the internal lead arrangement is difficult, which increases the difficulty of insulation design and assembly complexity. 2. Under lightning strike conditions, overvoltage is easily generated at the end of the low-voltage winding, requiring additional insulation design, which leads to increased manufacturing costs. 3. During long-term operation, transformer windings are prone to loosening due to thermal expansion and contraction. At the same time, the internal cooling oil flow rate is slow, limiting the cooling efficiency and affecting the reliability of equipment operation.

[0005] Therefore, a three-phase combined large power transformer with high impedance is proposed by a three-phase centralized overall arrangement method with built-in attached reactors. Summary of the Invention

[0006] The purpose of this invention is to provide a high-impedance three-phase combined large power transformer with a three-phase centralized overall arrangement of built-in reactors, in order to solve the problems of large space occupation of reactor arrangement, complex lead wires, high insulation cost due to easy overvoltage at the end of low voltage winding under lightning impact, and easy loosening and low cooling efficiency of transformer windings during long-term operation in the prior art.

[0007] To achieve the above objectives, the present invention provides the following technical solution: a three-phase combined large power transformer with a built-in integrated reactor and a three-phase centralized overall arrangement to achieve high impedance, comprising A-phase, B-phase, and C-phase transformer bodies, bellows, an oil-cooling system, a reactor system, winding assemblies, clamping assemblies, and a current-disrupting assembly; the A-phase, B-phase, and C-phase transformer bodies are connected by bellows; the bellows are connected between each group of transformer bodies; the oil-cooling system is located above the transformer bodies and is simultaneously connected to the A-phase, B-phase, and C-phase transformer bodies; the reactor system is arranged on one side of the C-phase; the winding assemblies are located inside the transformer bodies; the clamping assemblies are arranged between the winding assemblies; the current-disrupting assembly is vertically movable with the winding assemblies.

[0008] Preferably, the reactor system includes a reactor coil, an iron core, a support plate, and a through-connected long screw; the reactor coil is wound on an insulating paper tube on the outside of the iron core and is limited and fixed by the support plates arranged symmetrically above and below; the iron core is a plate structure, made of stacked electrical steel strips; the support plate, iron core, and reactor coil are pressed together by the long screw to form an independent structural unit; the entire reactor system is arranged in phase C, without interfering with the switch system and tap changer system of phase B, or with the low-voltage bushing outgoing line system of phase B, with a reasonable structure and convenient operation and installation.

[0009] Preferably, a surge arrester is connected in parallel across both ends of the reactor coil. The surge arrester is used to clamp the voltage at the beginning of the reactor coil under lightning strike conditions, thereby limiting the overvoltage at the end of the low-voltage winding. The surge arrester is a zinc oxide surge arrester and is located near the reactor coil, connected in parallel with the reactor coil via a connector.

[0010] Preferably, the winding assembly includes a central support, an insulating sleeve, a flow channel, a slot, a base plate, winding coils, a top plate, and a pad. The central support is fixedly connected inside the transformer body, the insulating sleeve is fixedly connected outside the central support, the flow channel is arranged in a circumferential array outside the insulating sleeve, the slot is engaged outside the insulating sleeve, the base plate is fixedly connected below the insulating sleeve, the winding coils are wound on the outside of the insulating sleeve, the top plate is threaded to the top of the insulating sleeve, and the pad is located in the slot and between two adjacent sets of winding coils. During the installation and assembly of the winding assembly, the winding coils need to be wound layer by layer on the outside of the insulating sleeve. After one layer is wound, the pad is placed between the winding coils to separate the upper and lower layers of winding coils, and the inner end of the pad is engaged with the slot, so that a channel for oil flow is formed between the upper and lower layers of winding coils.

[0011] Preferably, the clamping assembly includes a top block, a push rod, a slanted push block, a drive slant block, a check valve, a through hole, and a drive component; the top block is slidably connected to the pad block, the push rod is slidably connected to the inside of the pad block, the push rod is slidably in contact with the bottom of the top block, the slanted push block is fixedly connected to the push rod, the drive slant block is fixedly connected to the end of the push rod, the check valve is located on one side of the drive slant block, the through hole is opened on the pad block, and the drive component is inserted into the through hole.

[0012] Preferably, the driving component includes a driving rod, a driving groove, and a receiving groove; the driving rod is inserted into the through hole, and the driving groove and the receiving groove are both vertically through-holes on the outside of the driving rod; after the winding coil and the pad are installed, the driving groove on the driving rod can be aligned with the driving inclined block, and inserted into the through hole on the pad in the same vertical line in sequence, so that the driving inclined block is in the driving groove. Then, the driving rod is rotated so that the driving groove continuously pushes the pushing rod into the pad through the driving inclined block, and then the inclined push block at the top of the pushing rod continuously pushes the top block to rise. Then, rotating the driving rod can simultaneously drive the top block on the vertical pad in the same area to rise at the same time, thus spreading the winding coil between the top plate and the bottom plate.

[0013] Preferably, the anti-return element includes a ratchet, a mounting groove, a swing plate, a locking tooth, and a push spring; the ratchet is fixedly connected to the side wall of the pad on one side of the push rod, the mounting groove is formed on the push rod, the swing plate is oscillatingly connected to the mounting groove, the locking tooth is fixedly connected to the swing plate, and the push spring is fixedly connected between the swing plate and the push rod; as the push rod is pushed and moves continuously into the pad, the swing plate will be pushed and oscillate continuously by the push spring, and the locking tooth will continuously follow the forward movement and continuously abut against the ratchet in the forward direction, thereby ensuring that the position of the push rod after displacement is fixed, thereby limiting the position of the top block and keeping the top block in a state of supporting the winding coil.

[0014] Preferably, the number of top blocks on each set of pads is the same as the number of winding coils, so that the top blocks can simultaneously spread the winding coils in segments, preventing a certain turn of the winding coil from not contacting the top block.

[0015] Preferably, the turbulence-disrupting assembly includes a bottom support block, an electric push rod, a top ring frame, a connecting rod, and a turbulence-disrupting plate. The support block is fixedly connected to the bottom of the insulating sleeve, the electric push rod is fixedly connected to the top surface of the insulating sleeve, the top ring frame is fixedly connected to the output end of the electric push rod, the bottom of the connecting rod is slidably connected to the bottom support block, the top of the connecting rod is fixedly connected to the top ring frame, and the turbulence-disrupting plate is fixedly connected to the connecting rod. During operation, the electric push rod will continuously push the connecting rod up and down through the top ring frame, and the turbulence-disrupting plate will continuously disturb the coolant flowing in all directions through the channel between the guide channel and the winding coil, thereby effectively accelerating the cooling effect at the winding assembly.

[0016] Preferably, the number of connecting rods is the same as the number of guide channels, and the number of baffles is the same as the number of pads. Thus, as the connecting rods move up and down, the baffles can evenly agitate the liquid flow in the channels at each pad location, thereby enhancing the cooling effect of the coolant.

[0017] Compared with the prior art, the beneficial effects of the present invention are: 1. By centrally arranging the three phases of the reactor system on one side of phase C and connecting each phase transformer body with a corrugated pipe, the internal lead path is shortened, does not interfere with other systems, and saves space significantly. At the same time, zinc oxide surge arresters are connected in parallel at both ends of the reactor coil to effectively clamp the overvoltage at the end of the low-voltage winding under lightning strikes. No additional insulation reinforcement is required, which reduces manufacturing costs and improves operational safety.

[0018] 2. The drive rod sequentially drives the push rod and inclined push block in each pad block, so that the top block is evenly spread and compacted to form the winding coil. Combined with the one-way locking function of the check piece, the winding structure is kept tight for a long time, effectively solving the problem of winding loosening caused by temperature changes, and improving short circuit resistance and operational reliability.

[0019] 3. The top ring frame and connecting rod are moved up and down by the electric push rod. The baffles fixed on the connecting rod continuously agitate the cooling oil in the flow channel and winding gap, forcing the oil to circulate faster, thereby enhancing heat exchange, ensuring that the transformer temperature rise is controllable, and extending the service life of the equipment. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the overall three-dimensional structure of the present invention; Figure 2 This is the overall top view of the present invention; Figure 3 This is a schematic diagram of the winding assembly structure of the present invention; Figure 4 This is a schematic diagram of the clamping assembly structure of the present invention; Figure 5 This is a schematic diagram of the pad structure of the present invention; Figure 6 This is a cross-sectional view of the clamping assembly of the present invention; Figure 7 This is a schematic diagram of the check valve structure of the present invention; Figure 8 This is a schematic diagram of the turbulence component structure of the present invention.

[0021] In the diagram: 1. Transformer body; 2. Bellows; 3. Oil storage and cooling system; 4. Reactor system; 41. Reactor coil; 411. Surge arrester; 42. Iron core; 43. Support plate; 44. Long screw; 5. Winding assembly; 51. Central support; 52. Insulating sleeve; 53. Current guide channel; 54. Slot; 55. Base plate; 56. Winding coil; 57. Top plate; 58. Pad; 6. Clamping assembly; 61. Top block; 6 2. Push rod; 63. Angled push block; 64. Drive Angled block; 65. Check valve; 651. Ratchet; 652. Mounting slot; 653. Swing plate; 654. Clamping tooth; 655. Push spring; 66. Through hole; 67. Drive component; 671. Drive rod; 672. Drive slot; 673. Receiving slot; 7. Spoiler assembly; 71. Support block; 72. Electric push rod; 73. Top ring frame; 74. Connecting rod; 75. Spoiler plate. Detailed Implementation

[0022] 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.

[0023] Example 1

[0024] Please see Figures 1 to 2This invention provides a three-phase combined large power transformer with a built-in integrated reactor three-phase centralized overall arrangement to achieve high impedance. The technical solution is as follows: A three-phase combined large power transformer with a built-in integrated reactor three-phase centralized overall arrangement to achieve high impedance includes A-phase, B-phase, and C-phase transformer bodies 1, bellows 2, oil cooling system 3, reactor system 4, winding assembly 5, clamping assembly 6, and current-turbulence assembly 7; the A-phase, B-phase, and C-phase transformer bodies 1 are connected by bellows 2; the bellows 2 are connected between each group of transformer bodies 1; the oil cooling system 3 is located above the transformer bodies 1 and is simultaneously connected to the A-phase, B-phase, and C-phase transformer bodies 1; the reactor system 4 is arranged on the C-phase side; The winding assembly 5 is located inside the transformer body 1; the clamping assembly 6 is disposed between the winding assemblies 5; the turbulence assembly 7 is vertically movable with the winding assembly 5; the A-phase, B-phase, and C-phase transformer bodies 1 of this invention are detachably disposed and connected by a bellows 2 box. The bellows 2 serves as a connection channel for the internal leads of the transformer and can eliminate manufacturing and installation tolerances when connecting phases. A set of oil-cooling system 3 is provided, simultaneously supplying cooling oil to the three-phase transformer bodies 1 to meet cooling requirements; the integrated independent reactor system 4 is arranged in phase C, without excessive interference with the switching and tap changer systems of phase B, nor with the low-voltage bushing outgoing line system of phase B, resulting in a reasonable structure and convenient operation and installation. The short-circuit impedance performance of the transformer determines its resistance to short-circuit impacts and is a key factor in the stability of the smart grid system. The three-phase integrated sharing of the independent reactor system 4 improves the transformer's impedance, enhances its resistance to short-circuit impacts, and improves the stability of the smart grid system. At the same time, the stability of the transformer under lightning impulse test was solved; therefore, the lead connection between the independent reactor system 4 and the low voltage system of each phase transformer body 1 is clear and straightforward, without excessive intervention or interference with other systems, saving a lot of internal space and ensuring safety and reliability.

[0025] During operation, the winding assembly 5 utilizes the tightening and squeezing of the clamping assembly 6 to achieve a tight coil of the winding coil 56, preventing the winding coil 56 from becoming loose. It can also effectively prevent the temperature difference changes inside the transformer body 1 during operation from causing the winding coil 56 to loosen due to thermal expansion and contraction. At the same time, the turbulence assembly 7 can continuously fluctuate up and down inside the winding assembly 5, thereby agitating and accelerating the flow speed of the coolant inside the winding assembly 5, thus improving the cooling effect.

[0026] Reference Figure 1 and Figure 2The reactor system 4 includes a reactor coil 41, an iron core 42, a support plate 43, and a through-connected long screw 44. The reactor coil 41 is wound on an insulating paper tube on the outside of the iron core 42 and is limited and fixed by the support plates 43 arranged symmetrically above and below. The iron core 42 is a plate structure made of stacked electrical steel strips. The support plate 43, the iron core 42, and the reactor coil 41 are pressed together by the long screw 44 to form an independent structural unit. The entire reactor system 4 is arranged in phase C, without interfering with the switch system and tap changer system of phase B, or the outgoing line system of the low-voltage bushing of phase B. The structure is reasonable and easy to operate and install.

[0027] Reference Figure 1 A surge arrester 411 is connected in parallel across the reactor coil 41. The surge arrester 411 is used to clamp the voltage at the beginning of the reactor coil 41 under lightning impulse conditions, thereby limiting the overvoltage at the end of the low-voltage winding. The surge arrester 411 is a zinc oxide surge arrester 411, located near the reactor coil 41, and connected in parallel with the reactor coil 41 via a connector. The surge arrester 411 is a detachable unit, mounted next to the reactor coil 41 with a wire clamp, and connected to the reactor coil 41 via a connector. The surge arrester 41 clamps the voltage at the beginning of the reactor coil 41 in parallel. Since the beginning of the reactor system 4 is connected in series with the end of the low-voltage coil of the transformer body 1 and has the same potential, the voltage clamped at the beginning of the reactor system 4 by the surge arrester 411 is equivalent to clamping the voltage at the end of the low-voltage coil of the transformer body 1. During a lightning impulse test, when a full-wave lightning strike is applied to the beginning of the medium-voltage winding of the transformer body 1, the beginning of the low-voltage winding is grounded, and the end of the low-voltage winding is connected to the beginning of the reactor coil 41, which is in a floating state, while the end of the reactor coil 41 is grounded. Due to the capacitive coupling effect, a very high voltage will be induced at the end of the low-voltage winding of the transformer body 1. This voltage value is approximately twice or even higher than the impulse voltage that the low-voltage winding of the transformer body 1 can withstand. Therefore, the end insulation of the low-voltage winding of the transformer body 1 and the insulation of the connection wire between the low-voltage winding and the reactor coil 41 need to be strengthened, which increases the cost. The present invention uses a surge arrester 411 connected in parallel across the two ends of the reactor coil 41 to clamp the voltage within a reasonable range, which can not only reduce the cost of the product, but also improve the safety of the product operation.

[0028] Example 2

[0029] This embodiment further illustrates Example 1, referring to... Figure 3The winding assembly 5 includes a central support 51, an insulating sleeve 52, a current guiding channel 53, a slot 54, a base plate 55, a winding coil 56, a top plate 57, and a pad 58. The central support 51 is fixedly connected inside the transformer body 1. The insulating sleeve 52 is fixedly connected to the outside of the central support 51. The current guiding channel 53 is arranged in a circumferential array on the outside of the insulating sleeve 52. The slot 54 is engaged on the outside of the insulating sleeve 52. The base plate 55 is fixedly connected below the insulating sleeve 52. The winding coil 56 is wound on the outside of the insulating sleeve 52. The top plate 57 is threadedly connected to the top of the insulating sleeve 52. The pad 58 is located in the slot 54, and the pad 58... Located between two adjacent sets of winding coils 56; during the installation and assembly of the winding assembly 5, the winding coils 56 need to be wound layer by layer on the outside of the insulating sleeve 52. After one layer is wound, the pad 58 is placed between the winding coils 56 to separate the upper and lower layers of winding coils 56, and the inner end of the pad 58 is engaged with the slot 54, which can form a channel for oil flow between the upper and lower layers of winding coils 56. When used in conjunction with the flow guide channel 53, it can accelerate the flow rate of cooling oil and thus improve the cooling effect. After the winding coils 56 are wound, the top plate 57 can be threaded to the top of the insulating sleeve 52 and tightened, so that the winding coils 56 are clamped between the top plate 57 and the bottom plate 55.

[0030] Reference Figures 4 to 7 The clamping assembly 6 includes a top block 61, a push rod 62, an inclined push block 63, a driving inclined block 64, a check piece 65, a through hole 66, and a driving member 67. The top block 61 is slidably connected to the pad 58, the push rod 62 is slidably connected to the inside of the pad 58, the push rod 62 is slidably in contact with the bottom of the top block 61, the inclined push block 63 is fixedly connected to the push rod 62, the driving inclined block 64 is fixedly connected to the end of the push rod 62, the check piece 65 is located on one side of the driving inclined block 64, the through hole 66 is opened on the pad 58, and in the initial state, the driving inclined block 64 extends out and is in the through hole 66. The driving member 67 is inserted into the through hole 66. Reference Figure 7The driving component 67 includes a driving rod 671, a driving groove 672, and a receiving groove 673. The driving rod 671 is inserted into the through hole 66, and the driving groove 672 and the receiving groove 673 are both vertically through-holes on the outside of the driving rod 671. After the winding coil 56 and the pad 58 are installed, the driving groove 672 on the driving rod 671 is aligned with the driving inclined block 64, and then inserted into the through hole 66 on the pad 58 in the same vertical line, so that the driving inclined block 64 is in the driving groove 672. Then, the driving rod 671 is rotated so that the driving groove 672 continuously pushes the pushing rod 62 into the pad 58 through the driving inclined block 64, thereby using the pushing rod 671 to move the pushing rod 672 into the pad 58. 2. The inclined push block 63 at the top continuously pushes the top block 61 upward, thereby rotating the drive rod 671 to simultaneously drive the top block 61 on the vertical pad 58 in the same area to rise, thus spreading the winding coil 56 between the top plate 57 and the bottom plate 55. Then, the drive rod 671 is continuously pulled out to spread the top block 61 on the next set of vertical pads 58, thereby preventing gaps between some winding coils 56 that are not compacted. This prevents the winding coils 56 from loosening due to thermal expansion and contraction during use. Finally, the drive rod 671 can be rotated to the position of the receiving groove 673 to the drive inclined block 64, so that the drive inclined block 64 is located in the receiving groove 673, and then the drive rod 671 can be pulled out.

[0031] Reference Figure 7 The anti-return component 65 includes a ratchet 651, a mounting groove 652, a swing plate 653, a locking tooth 654, and a push spring 655. The ratchet 651 is fixedly connected to the side wall of the pad 58 on one side of the push rod 62. The mounting groove 652 is formed on the push rod 62. The swing plate 653 is swingably connected to the mounting groove 652. The locking tooth 654 is fixedly connected to the swing plate 653. The push spring 655 is fixedly connected between the swing plate 653 and the push rod 62. As the push rod 62 is pushed and moves continuously into the pad 58, the swing plate 653 will swing continuously under the push spring 655. The locking tooth 654 continuously follows the forward movement and abuts against the ratchet 651 in the forward direction, thereby ensuring that the position of the push rod 62 after displacement is fixed, thereby limiting the position of the top block 61 and keeping the top block 61 in a state of supporting the winding coil 56.

[0032] Reference Figure 5 The number of top blocks 61 on each set of pads 58 is consistent with the number of turns of the winding coil 56. Thus, the top blocks 61 can simultaneously and segmentally open the winding coil 56 to prevent a turn of the winding coil 56 from not contacting the top block 61.

[0033] Example 3

[0034] This embodiment further illustrates Example 1, referring to... Figure 8The turbulence-dissipating assembly 7 includes a bottom support block 71, an electric push rod 72, a top ring frame 73, a connecting rod 74, and a turbulence-dissipating plate 75. The support block 71 is fixedly connected to the bottom of the insulating sleeve 52, the electric push rod 72 is fixedly connected to the top surface of the insulating sleeve 52, the top ring frame 73 is fixedly connected to the output end of the electric push rod 72, the bottom of the connecting rod 74 is slidably connected to the bottom support block 71, the top of the connecting rod 74 is fixedly connected to the top ring frame 73, and the turbulence-dissipating plate 75 is fixedly connected to the connecting rod 74. During operation, the electric push rod 72 will continuously push the connecting rod 74 up and down through the top ring frame 73. During the up and down movement of the connecting rod 74, the bottom will slide up and down along the bottom support block 71. At the same time, during the up and down movement of the connecting rod 74, the turbulence-dissipating plate 75 will continuously disturb the coolant in the channel between the guide channel 53 and the winding coil 56 to flow in all directions, thereby effectively accelerating the cooling effect at the winding assembly 5.

[0035] Reference Figure 8 The number of connecting rods 74 is the same as the number of guide channels 53, and the number of baffles 75 is the same as the number of pads 58. Thus, as the connecting rods 74 move up and down, the baffles 75 can evenly agitate the liquid flow in the channels at each pad 58 location, thereby enhancing the cooling effect of the coolant.

[0036] Working principle: First, three independent transformer bodies 1 (phase A, phase B, and phase C) are connected by bellows 2 to form a detachable three-phase combined structure. The oil-cooling system 3 is simultaneously connected to the three-phase bodies, providing circulating cooling oil to the internal winding assembly 5. The reactor system 4, as an independent structural unit, is centrally located on the C-phase side, with its reactor coil 41 connected in series with the end of the low-voltage winding of the transformer body 1. Simultaneously, zinc oxide surge arresters 411 are installed in parallel across the reactor coil 41 for subsequent overvoltage protection. Then, during the installation of winding assembly 5, after the winding coils 56 are wound layer by layer on the outside of the insulating sleeve 52 and the pads 58 are placed between adjacent winding coils 56, the operator inserts the drive rod 671 into the through holes 66 of each pad 58 in the same vertical line. When the drive rod 671 is rotated, the drive groove 672 pushes the push rod 62 into the pad 58 through the drive wedge 64. The wedge push block 63 at the front end of the push rod 62 simultaneously lifts the top block 61 and slides it upward, so that the top block 61 evenly spreads and compacts the winding coils 56 between the top plate 57 and the bottom plate 55. During this process, the locking teeth 654 in the check piece 65 engage with the ratchet 651 in one direction to ensure that the positions of the push rod 62 and the top block 61 are locked, preventing the winding coils 56 from loosening due to thermal expansion and contraction, thereby maintaining the tight state of the winding structure for a long time.

[0037] Finally, during transformer operation, the electric actuator 72 periodically moves, driving the connecting rod 74 and the baffle 75 to reciprocate up and down along the flow channel 53 outside the insulating sleeve 52 via the top ring frame 73. The baffle 75's disturbance effect accelerates the flow rate of cooling oil in the gap of the winding coil 56 and the flow channel 53, significantly improving heat dissipation efficiency and ensuring controllable transformer temperature rise. Simultaneously, when a lightning strike occurs, a full-wave lightning strike is applied to the beginning of the medium-voltage winding, and a high-amplitude overvoltage is generated at the end of the low-voltage winding due to capacitive coupling. At this time, the zinc oxide surge arrester 411 connected in parallel across the reactor coil 41 quickly activates, clamping the voltage at the beginning of the reactor coil 41 and the voltage at the end of the low-voltage winding of the transformer body 1, limiting them within a reasonable range. This protects the insulation and connecting wires at the end of the low-voltage winding, avoids increased costs due to insulation reinforcement, and improves product operational safety.

[0038] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

Claims

1. A three-phase combined large power transformer with built-in attached reactors, characterized in that it achieves high impedance through a centralized three-phase integrated arrangement, is characterized in that: The transformer body includes A-phase, B-phase, and C-phase (1), bellows (2), oil storage and cooling system (3), reactor system (4), winding assembly (5), clamping assembly (6), and turbulence assembly (7). The transformer bodies (1) of phase A, phase B, and phase C are connected by a bellows (2); the bellows (2) are connected between each group of transformer bodies (1); the oil storage and cooling system (3) is located above the transformer body (1) and is connected to the transformer bodies (1) of phase A, phase B, and phase C at the same time; the reactor system (4) is arranged on the side of phase C; the winding assembly (5) is located inside the transformer body (1); the clamping assembly (6) is arranged between the winding assemblies (5); the turbulence assemblies (7) are moved up and down with the winding assemblies (5).

2. A three-phase combined large power transformer with high impedance realized in a three-phase centralized integral arrangement with a built-in reactor according to claim 1, characterized in that: The reactor system (4) includes a reactor coil (41), an iron core (42), a support plate (43), and a through-connected long screw (44); the reactor coil (41) is wound on an insulating paper tube outside the iron core (42) and is fixed by the support plate (43) arranged symmetrically above and below; the iron core (42) is a plate structure, which is made of stacked electrical steel strips; the support plate (43), the iron core (42), and the reactor coil (41) are pressed together by the long screw (44) to form an independent structural unit.

3. A high-impedance three-phase combined large power transformer with a built-in attached reactor three-phase centralized overall arrangement as described in claim 2, characterized in that: A surge arrester (411) is connected in parallel across the two ends of the reactor coil (41). The surge arrester (411) is used to clamp the voltage at the beginning of the reactor coil (41) under lightning strike conditions, thereby limiting the overvoltage at the end of the low-voltage winding. The surge arrester (411) is a zinc oxide surge arrester (411) and is located near the reactor coil (41), and is connected in parallel with the reactor coil (41) through a connector.

4. A high-impedance three-phase combined large power transformer with a built-in attached reactor three-phase centralized integrated arrangement as described in claim 3, characterized in that: The winding assembly (5) includes a central support (51), an insulating sleeve (52), a current guiding channel (53), a slot (54), a base plate (55), a winding coil (56), a top plate (57), and a pad (58). The central support (51) is fixedly connected inside the transformer body (1), the insulating sleeve (52) is fixedly connected outside the central support (51), the current guiding channel (53) is arranged in a circumferential array outside the insulating sleeve (52), the slot (54) is engaged outside the insulating sleeve (52), the base plate (55) is fixedly connected below the insulating sleeve (52), the winding coil (56) is wound outside the insulating sleeve (52), the top plate (57) is threaded to the top of the insulating sleeve (52), the pad (58) is located in the slot (54), and the pad (58) is located between two adjacent sets of winding coils (56).

5. A high-impedance three-phase combined large power transformer with a built-in attached reactor three-phase centralized integrated arrangement as described in claim 4, characterized in that: The clamping assembly (6) includes a top block (61), a push rod (62), a slanted push block (63), a drive slant block (64), a check piece (65), a through hole (66), and a drive member (67); the top block (61) is slidably connected to the pad (58) vertically, the push rod (62) is slidably connected to the inside of the pad (58), the push rod (62) is slidably in contact with the bottom of the top block (61), the slanted push block (63) is fixedly connected to the push rod (62), the drive slant block (64) is fixedly connected to the end of the push rod (62), the check piece (65) is located on one side of the drive slant block (64), the through hole (66) is opened on the pad (58), and the drive member (67) is inserted into the through hole (66).

6. A high-impedance three-phase combined large power transformer with a built-in attached reactor three-phase centralized integrated arrangement as described in claim 5, characterized in that: The driving component (67) includes a driving rod (671), a driving groove (672), and a receiving groove (673); the driving rod (671) is inserted into the through hole (66), and the driving groove (672) and the receiving groove (673) are both opened vertically on the outside of the driving rod (671).

7. A high-impedance three-phase combined large power transformer with a built-in attached reactor three-phase centralized integrated arrangement as described in claim 6, characterized in that: The check valve (65) includes a ratchet (651), a mounting groove (652), a swing plate (653), a locking tooth (654), and a push spring (655); the ratchet (651) is fixedly connected to the side wall of the pad (58) on one side of the push rod (62), the mounting groove (652) is opened on the push rod (62), the swing plate (653) is swayingly connected to the mounting groove (652), the locking tooth (654) is fixedly connected to the swing plate (653), and the push spring (655) is fixedly connected between the swing plate (653) and the push rod (62).

8. A high-impedance three-phase combined large power transformer with a built-in attached reactor three-phase centralized integrated arrangement as described in claim 7, characterized in that: The number of top blocks (61) on each set of pads (58) is the same as the number of winding coils (56).

9. A high-impedance three-phase combined large power transformer with a built-in attached reactor three-phase centralized integrated arrangement as described in claim 8, characterized in that: The turbulence-disrupting assembly (7) includes a bottom support block (71), an electric actuator (72), a top ring frame (73), a connecting rod (74), and a turbulence-disrupting plate (75). The support block (71) is fixedly connected to the bottom of the insulating sleeve (52), the electric actuator (72) is fixedly connected to the top surface of the insulating sleeve (52), the top ring frame (73) is fixedly connected to the output end of the electric actuator (72), the bottom of the connecting rod (74) is slidably connected to the bottom support block (71), the top of the connecting rod (74) is fixedly connected to the top ring frame (73), and the turbulence-disrupting plate (75) is fixedly connected to the connecting rod (74).

10. A high-impedance three-phase combined large power transformer with a built-in attached reactor three-phase centralized overall arrangement as described in claim 9, characterized in that: The number of connecting rods (74) is the same as the number of guide channels (53), and the number of baffles (75) is the same as the number of pads (58).

Images