High-voltage winding end outgoing line insulation structure and method and transformer

Abstract

The invention relates to the technical field of transformers, and discloses a high-voltage winding end outgoing line insulation structure and method and a transformer, and the high-voltage winding end outgoing line insulation structure comprises a pressing plate area, a paper-wrapped cable, a lead support and an ascending flanged base which are sequentially arranged at the end of a high-voltage winding; a shielding electrode section is arranged between the end part of the high-voltage winding and the paper-wrapped cable after the end part of the high-voltage winding is led out through a winding original wire and passes through a pressing plate area; a primary multi-layer corrugated board is arranged when the winding original wire passes through the pressing plate area; the winding original wire is led out of the pressing plate area and then is connected with a paper-wrapped cable, the paper-wrapped cable is fixed by a wire clamp at the lead bracket, and a secondary multi-layer corrugated board is arranged between the paper-wrapped cable and the wire clamp; and the second-stage multi-layer corrugated board is arranged beyond the grading ring at the lower part of the ascending flanged base. The technical problems that due to the fact that a large gap needs to be reserved due to the high-voltage outgoing line insulation requirement and the balance winding is arranged close to the iron core, the distance between the low-voltage winding and the iron core and the distance between the high-voltage winding and the iron core are large, load loss is high, material consumption is large, and overall structural rationality, process feasibility and economical efficiency are insufficient are solved.

Description

Technical Field

[0001] This invention relates to the field of transformer technology, specifically to a high-voltage winding end lead insulation structure, method, and transformer. Background Technology

[0002] In power systems, ultra-high voltage transformers with voltage levels of 330kV and above are core equipment in the power grid transmission process, and their winding insulation performance directly determines the safety and reliability of the equipment operation. For this type of transformer, in order to reduce the difficulty of insulation design and insulation level requirements at the winding ends, the existing technology generally adopts a structural design scheme in which the high-voltage winding leads out from the middle.

[0003] When a transformer is equipped with a balancing winding, the conventional winding arrangement from the inside out under existing technology is: core → balancing winding → low-voltage winding → high-voltage winding → voltage regulating winding. This winding arrangement, combined with the structure of the high-voltage winding with a lead-out in the middle, has the following inherent defects: 1. Problem of voltage regulating winding structure segmentation: Because the high-voltage winding adopts a center-outlet configuration, the voltage regulating winding must be forcibly divided into two independent upper and lower windings. Furthermore, to meet electrical performance requirements, the upper and lower voltage regulating windings are usually designed in parallel. Simultaneously, due to the limitations of the high-voltage outlet insulation class, a large gap must be reserved between the upper and lower voltage regulating windings. This gap not only increases the overall volume of the transformer but also significantly reduces the space utilization rate of the winding arrangement.

[0004] 2. Defects in the insulation structure of high-voltage leads: Regarding the insulation structure of the aforementioned centrally exiting leads, existing technologies typically employ an equipotential bonding tube structure for insulation and shielding of high-voltage winding leads. The design features of this equipotential bonding tube structure are: the tube itself has a large diameter and requires a thick outer insulation layer; the high-voltage winding leads are led out through the inside of the tube. Thanks to the shielding effect of the equipotential bonding tube, the high-voltage winding leads themselves only require a thin insulation layer to meet insulation requirements. However, this structure presents significant technical bottlenecks in actual production and assembly. Equipotential bonding at one end is required between the equipotential bonding tube and the high-voltage winding leads. However, due to the limited internal space of the equipotential bonding tube, the operable space between the tube and the leads is extremely small, making the equipotential bonding operation extremely difficult. This not only affects assembly efficiency but may also leave safety hazards due to connection quality issues.

[0005] In addition, the equalizing tube itself has a long processing cycle and high manufacturing cost, which further increases the production cycle and overall cost of the transformer, which is not conducive to the large-scale production and economic optimization of this type of ultra-high voltage transformer. Summary of the Invention

[0006] In order to overcome the defects of the prior art, the present invention aims to provide a high-voltage winding end outlet insulation structure, method and transformer to solve the technical problems of insufficient structural rationality, process feasibility and economy due to the large gap required for high-voltage outlet insulation and the large distance between the low-voltage and high-voltage (including voltage regulating) windings and the core caused by the close proximity of the balancing winding to the core.

[0007] This invention is achieved through the following technical solution: In a first aspect, the present invention provides a high-voltage winding end lead insulation structure, comprising a pressure plate area, a paper-insulated cable, a lead wire bracket, and a riser arranged sequentially at the end of the high-voltage winding; The end of the high-voltage winding is led out through the winding primary line, passes through the pressure plate area, and is provided with a shielded electrode section between it and the paper-insulated cable. When the primary winding passes through the pressure plate area, a multi-layer corrugated cardboard is provided for oil gap separation; The primary winding wire is led out of the pressure plate area and connected to the paper-insulated cable. The paper-insulated cable is fixed by the wire clamp at the lead wire bracket. A secondary multi-layer corrugated cardboard is provided between the paper-insulated cable and the wire clamp. The secondary multi-layer corrugated cardboard is set beyond the lower equalizing ring of the riser.

[0008] Preferably, the shielding electrode segment includes cotton thread, aluminum foil crepe paper, and shielding wire; after the winding primary wire is arranged in a rectangular shape, it is filled with cotton thread to form a circular or elliptical structure, and aluminum foil crepe paper is wrapped around the outside of the circular or elliptical structure. The shielding wire is pre-embedded inside the aluminum foil crepe paper and is pressed at the same potential as the winding primary wire.

[0009] Preferably, the primary multi-layer corrugated cardboard in the pressure plate area is also provided with additional insulation. The primary multi-layer corrugated cardboard and the additional insulation are wrapped around the outside of the winding primary wire at intervals, and several binding straps are tied at both ends of the wrapping structure to ensure tightness.

[0010] Preferably, the crimping area between the primary winding and the paper-insulated cable is wrapped with semiconductor crepe paper for electrode shielding; the connection end of the paper-insulated cable is formed into a bevel after the insulation is removed, and the bevel and the primary winding are wrapped together with heat-resistant crepe paper.

[0011] Furthermore, the wrapping height of the heat-resistant crepe paper is 8 to 10 times the thickness of the paper-insulated cable. After the crimping area is wrapped with insulation, a layer of corrugated cardboard is also tied to the outside. The corrugated cardboard is an extension of a layer in a two-stage multi-layer corrugated cardboard.

[0012] Furthermore, after the primary winding is led out of the pressure plate area, it is connected to the paper-insulated cable through a cold wire connector.

[0013] Preferably, the secondary multi-layer corrugated cardboard between the conductor clamp and the paper-sheathed cable is arranged in an intermittent manner to achieve oil gap separation insulation.

[0014] Preferably, the secondary multi-layer corrugated cardboard extends beyond the height of the equalizing ring at the bottom of the riser seat to meet the insulation withstand voltage requirements of the riser seat area.

[0015] Secondly, the present invention also provides a method for insulating the end leads of a high-voltage winding, based on the aforementioned high-voltage winding end lead insulation structure, comprising the following process: Lead out the primary winding from the high voltage winding, perform shielding electrode treatment on the primary winding, arrange the primary winding into a rectangle, fill it with cotton thread to form a circle or ellipse, wrap it with aluminum foil crepe paper and pre-embed shielding wire, so that the shielding wire and the primary winding are pressed together at the same potential to form a shielding electrode section. The primary winding with shielded electrode section is passed through the pressure plate area. The area is wrapped with a multi-layer corrugated cardboard and an insulating spacer. The two ends are tied with binding tape. The oil gap is divided by the multi-layer corrugated cardboard. The winding primary wire is crimped with the paper-insulated cable. After the crimped joint is tidied, it is wrapped with semiconductor crepe paper for shielding. The insulation of the paper-insulated cable is removed to form a bevel. It is wrapped with heat-resistant crepe paper together with the winding primary wire, and a layer of corrugated cardboard is tied to the outside. Pass the paper-insulated cable through the lead wire bracket and fix it with the wire clamp. Place a two-stage multi-layer corrugated cardboard between the paper-insulated cable and the wire clamp to divide the oil gap. A two-stage multi-layer corrugated cardboard is installed between the paper-insulated cable and the conductor clamp to ensure that the height of the multi-layer corrugated cardboard exceeds the equalizing ring at the bottom of the riser, thus completing the overall insulation protection.

[0016] Thirdly, the present invention also provides a transformer, comprising an iron core, a low-voltage winding, a high-voltage winding, a voltage regulating winding, and a balancing winding arranged sequentially from the inside to the outside; the high-voltage winding is provided with the aforementioned high-voltage winding end lead insulation structure.

[0017] Compared with the prior art, the present invention has the following beneficial technical effects: This invention provides an insulation structure for the high-voltage winding end outlet, which achieves shielding at the lead end through shielded electrode sections and extends the lead wires using paper-insulated cables, completely replacing the equalizing tube structure and avoiding the drawbacks of long processing cycles, high costs, and difficulties in equipotential bonding associated with equalizing tubes. The oil gap segmentation design of the multi-layer corrugated cardboard solves the problem of short-distance withstand voltage in key areas of the high-voltage outlet (passing through pressure plates, wire clamps, and corrugated body), and the corrugated height exceeds the equalizing ring of the riser seat, avoiding insulation blind spots. The high-voltage winding end outlet eliminates the need to divide the voltage regulating winding into upper and lower sections, eliminates the middle gap, reduces the overall volume of the transformer, and improves space utilization.

[0018] Furthermore, the shielding wire is directly crimped to the primary winding wire, eliminating the need for operation in confined spaces (such as equalizing tubes). This process is simple and the connection is reliable, avoiding electric field distortion caused by poor connection. The cotton filling ensures the regular shape of the primary winding wire, and the aluminum foil corrugated paper forms a uniform shielding layer, effectively dispersing the electric field at the lead-out end, improving shielding reliability, and reducing the risk of insulation breakdown.

[0019] Furthermore, the arrangement of the multi-layer corrugated cardboard and the attached insulation divides the long oil gap into multiple short oil gaps. Utilizing the exponential relationship between oil withstand voltage and oil gap length, the insulation withstand voltage capability of the pressure plate area is significantly improved. Two binding straps are tied at both ends to prevent the multi-layer corrugated cardboard and the attached insulation from loosening or shifting, ensuring the long-term effectiveness of the oil gap division structure and adapting to the vibration environment during transformer operation.

[0020] Furthermore, the semiconductor crepe paper wrapping of the crimping area ensures a uniform electric field distribution at the crimping point, preventing localized partial discharge caused by excessively high local electric field strength and extending insulation life. The slanted design of the paper-insulated cable reduces abrupt changes in insulation transition. Combined with the heat-resistant crepe paper wrapping, it forms a continuous insulating protective layer, improving the insulation reliability at the crimping point and adapting to the high-temperature environment during transformer operation.

[0021] Furthermore, the transition bevel wrapped with heat-resistant crease paper with an insulation thickness of 8 to 10 times that of the cable ensures that the insulation transition at the crimping point meets the insulation requirements of the 330kV voltage level, avoiding breakdown due to insufficient taper of the bevel; the multi-layer corrugated cardboard tied on the outside further strengthens the insulation and can also buffer the impact of external forces or oil flow on the insulation layer of the crimping area, improving the structural damage resistance.

[0022] Furthermore, the spaced arrangement of the two-stage multi-layer corrugated cardboard divides the oil gap between the paper-sheathed cable and the grounding conductor into multiple short oil gaps in a narrow space, significantly improving the local insulation withstand voltage capability and adapting to small-pitch scenarios; the spaced arrangement does not require additional space and can be directly adapted to the size of existing lead brackets and wire clamps, without the need to modify other components of the transformer, reducing design and modification costs.

[0023] Furthermore, the height of the secondary multi-layer corrugated cardboard exceeds that of the equalizing ring, ensuring that the insulation protection covers the connection area between the equalizing ring and the paper-sheathed cable, thus avoiding insulation failures caused by electric field distortion around the equalizing ring; ensuring that the insulation level of the riser area matches that of other areas of the high-voltage outgoing line, thus preventing the overall insulation reliability from being reduced due to local weaknesses.

[0024] This invention also provides a method for insulating the lead wires at the end of high-voltage windings. It eliminates the need for traditional equalizing tubes. The shielding electrode treatment involves filling with cotton thread, wrapping with aluminum foil crepe paper, and equipotential bonding of the shielding wire. This simplifies the equipotential bonding operation and disperses the electric field at the lead wires of the winding, preventing insulation breakdown. During the pressing process, multiple layers of corrugated cardboard divide the oil gap to increase withstand voltage, and binding ensures structural stability. Semiconductor crepe paper at the pressing point suppresses electric field concentration, heat-resistant crepe paper is suitable for high-temperature environments, and the outer corrugated cardboard provides enhanced protection. The corrugated cardboard at the wire clamp is suitable for insulation requirements in small spaces, requiring no modification to existing components; the corrugated cardboard extending beyond the equalizing ring of the riser eliminates insulation blind spots. The overall process is simple and standardized, reducing operational difficulty and cost, while simultaneously improving the insulation reliability and production efficiency of the lead wires at the end of the high-voltage windings.

[0025] This invention provides a transformer in which the external balancing winding shortens the distance from the low-voltage, high-voltage, and voltage-regulating windings to the core, reduces the total winding length, directly reduces load loss, and also reduces the amount of winding materials used, thus improving economy. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the insulation structure of the high-voltage winding end lead in an embodiment of the present invention. Figure 2 for Figure 1 Enlarged cross-sectional view of the middle AA section; Figure 3 This is a schematic diagram of the transformer structure in an embodiment of the present invention; In the diagram: 1. High-voltage winding; 2. Winding primary wire; 3. Pressure plate area; 4. Shielding electrode section; 5. Primary multi-layer corrugated cardboard; 6. Paper-insulated cable; 7. Wire clamp; 8. Secondary multi-layer corrugated cardboard; 9. Raising seat; 10. Lead wire bracket; 11. Low-voltage winding; 12. Voltage regulating winding; 13. Balance winding; 14. Iron core; 41. Cotton thread; 42. Aluminum foil crepe paper; 43. Shielding wire. Detailed Implementation

[0027] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. 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 should fall within the scope of protection of the present invention.

[0028] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0029] The purpose of this invention is to provide an insulation structure, method, and transformer for the high-voltage winding end outlet, in order to solve the technical problems of insufficient structural rationality, process feasibility, and economy caused by the large gap required for high-voltage outlet insulation and the close proximity of the balancing winding to the core, resulting in large distances between the low-voltage and high-voltage (including voltage regulating) windings and the core, high load losses, and high material consumption.

[0030] The present invention will now be described in further detail with reference to the accompanying drawings: Example 1 See Figure 1 In one embodiment of the present invention, a high-voltage winding end lead insulation structure is provided, including a pressure plate area 3, a paper-insulated cable 6, a lead wire bracket 10, and a riser seat 9 arranged sequentially at the end of the high-voltage winding 1; a shielding electrode section 4 is provided between the end of the high-voltage winding 1, after the winding primary wire 2 passes through the pressure plate area 3 and the paper-insulated cable 6; a first-stage multi-layer corrugated cardboard 5 is provided when the winding primary wire 2 passes through the pressure plate area 3 for oil gap separation; the winding primary wire 2 is connected to the paper-insulated cable 6 after exiting the pressure plate area 3, and the paper-insulated cable 6 is fixed by a wire clamp 7 at the lead wire bracket 10; a second-stage multi-layer corrugated cardboard 8 is provided between the paper-insulated cable 6 and the wire clamp 7; the second-stage multi-layer corrugated cardboard 8 extends beyond the lower equalizing ring of the riser seat 9.

[0031] Specifically, according to Figure 2 As shown, the shielding electrode segment 4 includes cotton thread 41, aluminum foil crepe paper 42, and shielding wire 43; after the winding primary wire 2 is arranged in a rectangular shape, it is filled with cotton thread 41 to form a circular or elliptical structure, and aluminum foil crepe paper 42 is wrapped around the outside of the circular or elliptical structure. The shielding wire 43 is embedded inside the aluminum foil crepe paper 42 and is pressed at the same potential as the winding primary wire 2.

[0032] In this embodiment, the shielding electrode segment 4 is located inside the molded corner ring and is fixed by the molded corner ring.

[0033] In this embodiment, the primary winding wires are first arranged into a rectangle, and then filled with cotton thread to form a circle / ellipse. The regular shape avoids the electric field concentration caused by the irregularity of the wires. The outer part is wrapped with aluminum foil crepe paper, and the conductivity of aluminum foil forms a continuous shielding layer, which further disperses the electric field at the lead-out end and reduces the local field strength. The shielding wire is pre-embedded inside the aluminum foil crepe paper and is pressed at the same potential as the primary winding wire, eliminating the potential difference between the shielding layer and the wire, avoiding electric field distortion caused by uneven potential, replacing the shielding and equipotential functions of the traditional equalizing tube, and the structure is more suitable for narrow spaces.

[0034] Specifically, the primary multi-layer corrugated cardboard 5 in the pressure plate area 3 is also provided with additional insulation. The primary multi-layer corrugated cardboard 5 and the additional insulation are wrapped around the outside of the winding primary wire 2 at intervals, and several binding straps are tied at both ends of the wrapping structure to ensure tightness.

[0035] In this embodiment, the primary multi-layer corrugated cardboard and the insulating spacer wrap the winding primary wire, dividing the long oil gap in the pressure plate area into several short oil gaps. Based on the characteristic that "the withstand voltage of oil decreases exponentially with the length of the oil gap", the insulation withstand voltage capability of this area is improved. Several binding straps are tied at both ends to prevent the corrugated cardboard and the insulating spacer from shifting due to transformer operation vibration, maintain the stability of the oil gap division structure, and ensure long-term insulation effectiveness.

[0036] Specifically, the crimping area between the primary winding 2 and the paper-insulated cable 6 is wrapped with semiconductor crepe paper for electrode shielding; after the insulation is removed from the connection end of the paper-insulated cable 6, a bevel is formed, and the bevel and the primary winding 2 are wrapped together with heat-resistant crepe paper.

[0037] In this embodiment, the crimping area is wrapped with semiconductor crepe paper. The conductivity of the semiconductor material is used to create a uniform electric field, avoiding electric field concentration caused by the crimping joint (irregular part of the metal) and suppressing partial discharge. The insulation of the paper-insulated cable connection end is removed to form a bevel, reducing the sudden change in field strength caused by the abrupt change in the insulation layer. Then, together with the winding primary wire, heat-resistant crepe paper is wrapped to form a continuous insulating protective layer, which is suitable for the high-temperature environment in transformer operation and avoids the risk of breakdown caused by insulation breakage.

[0038] The wrapping height of the heat-resistant crepe paper is 8 to 10 times the thickness of the paper-insulated cable 6. After the crimping area is wrapped with insulation, a layer of corrugated cardboard is also tied to the outside. The corrugated cardboard is an extension of one layer of the secondary multi-layer corrugated cardboard 8.

[0039] Among them, the primary winding 2 is led out of the pressure plate area 3 and then connected to the paper-insulated cable 6 through the cold wire connector.

[0040] In this embodiment, the wrapping height of the heat-resistant crepe paper is set to 8 to 10 times the insulation thickness of the paper-sheathed cable. The sufficient slant height matches the insulation requirements of the 330kV voltage level, preventing withstand voltage failure due to insufficient thickness. A layer of multi-layer corrugated cardboard is bound to the outside of the crimping area. This not only further strengthens the insulation through the oil gaps in the corrugated cardboard, but also buffers the impact of external forces and oil flow on the internal heat-resistant crepe paper, improving the insulation resistance of the crimping area.

[0041] Specifically, the secondary multi-layer corrugated cardboard 8 between the conductor clamp 7 and the paper-insulated cable 6 is arranged in an intermittent manner to achieve oil gap separation insulation.

[0042] In this embodiment, the distance between the wire clamp and the paper-insulated cable is small. The use of a two-stage multi-layer corrugated cardboard with spaced arrangement can divide the single oil gap between the two into multiple short oil gaps in a limited space. The insulation withstand voltage can be significantly improved without increasing the distance between components. It is compatible with the existing size of the lead bracket and the wire clamp, avoiding increased costs due to structural modifications.

[0043] Specifically, the height of the secondary multi-layer corrugated cardboard 8 exceeds that of the equalizing ring at the bottom of the riser seat 9 to meet the insulation withstand voltage requirements of the riser seat 9 area.

[0044] In this embodiment, the area around the equalizing ring at the bottom of the riser is prone to insulation weakness due to electric field distortion. The height of the multi-layer corrugated cardboard exceeds that of the equalizing ring, so the insulation protection can cover the distorted area, keeping the electric field strength around the equalizing ring within a safe range. This ensures that the insulation level of the riser area matches that of other areas of the high-voltage outgoing line, avoiding local weaknesses that could lower the overall insulation reliability.

[0045] In this embodiment, the high-voltage winding end-out method is adopted, eliminating the need to divide the voltage regulating winding into upper and lower windings, eliminating the gap in the middle of the voltage regulating winding, further reducing the winding size, and reducing material consumption. A shielded electrode structure is used instead of the traditional equalizing tube structure, solving the problems of long processing cycle, high cost, and difficult equipotential connection operation of the equalizing tube. The shielded electrode structure ensures the insulation performance of the outgoing wires by filling, shaping, and shielding the original winding wires. Oil gap segmentation technology is used for insulation design, dividing a long oil gap into several short-distance oil gaps through insulation isolation. Since the withstand voltage of oil decreases exponentially with the oil gap length, shortening the oil gap length can exponentially increase the withstand voltage of the oil, effectively solving the technical problem of withstanding high voltage over short distances.

[0046] Example 2 This embodiment also provides a method for insulating the end leads of a high-voltage winding, based on the aforementioned high-voltage winding end lead insulation structure, including the following process: Lead the primary wire 2 of the high voltage winding 1, perform shielding electrode treatment on the primary wire 2, arrange the primary wire 2 into a rectangle, fill it into a circle or ellipse with cotton thread 41, wrap it with aluminum foil crepe paper 42 and pre-embed shielding wire 43, so that the shielding wire 43 is pressed with the primary wire 2 at the same potential to form shielding electrode segment 4. The primary winding 2 with shielded electrode section 4 is passed through the pressure plate area 3. The primary winding is wrapped with a multi-layer corrugated cardboard 5 and an insulating spacer in the passing area. Two binding straps are tied at both ends. The oil gap is divided by the multi-layer corrugated cardboard 5. The primary winding 2 is crimped with the paper-insulated cable 6. After the crimped joint is tidied, a semiconductor crepe paper shield is wrapped around it. The insulation of the paper-insulated cable 6 is removed to form a bevel. It is wrapped together with the primary winding 2 with heat-resistant crepe paper, and a layer of corrugated cardboard is tied to the outside. Pass the paper-insulated cable 6 through the lead wire bracket 10 and fix it with the wire clamp 7. Set a two-stage multi-layer corrugated cardboard 8 between the paper-insulated cable 6 and the wire clamp 7 to divide the oil gap. A secondary multi-layer corrugated cardboard 8 is installed between the paper-insulated cable 6 and the conductor clamp 7 to ensure that the height of the multi-layer corrugated cardboard 8 exceeds the lower equalizing ring of the riser 9, thus completing the overall insulation protection.

[0047] In summary, this invention also provides a method for insulating the lead wires at the end of a high-voltage winding. It eliminates the need for traditional equalizing tubes. The shielding electrode treatment utilizes cotton thread filling, aluminum foil crepe paper wrapping, and equipotential bonding of the shielding wire. This simplifies the equipotential bonding operation and disperses the electric field at the lead wire's origin, preventing insulation breakdown. During the pressure plate installation, multiple layers of corrugated cardboard divide the oil gap to enhance withstand voltage, and binding ensures structural stability. Semiconductor crepe paper at the bonding point suppresses electric field concentration, heat-resistant crepe paper is suitable for high-temperature environments, and the outer corrugated cardboard provides enhanced protection. The corrugated cardboard at the wire clamp adapts to the insulation requirements of small spaces, requiring no modification to existing components; the corrugated cardboard extending beyond the equalizing ring of the riser eliminates insulation blind spots. The overall process is simple and standardized, reducing operational difficulty and cost, while simultaneously improving the insulation reliability and production efficiency of the lead wires at the end of the high-voltage winding.

[0048] Example 3 according to Figure 3 As shown, this embodiment also provides a transformer, including an iron core 14, a low-voltage winding 11, a high-voltage winding 1, a voltage regulating winding 12, and a balancing winding 13 arranged sequentially from the inside to the outside; the high-voltage winding 1 is provided with the high-voltage winding end lead insulation structure described above.

[0049] In summary, the transformer provided by this invention has an externally mounted balancing winding that shortens the distance between the low-voltage, high-voltage, and voltage-regulating windings and the core, reduces the total winding length, directly reduces load losses, and also reduces the amount of winding materials used, thereby improving economic efficiency.

[0050] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A high-voltage winding end lead insulation structure, characterized in that, It includes a pressure plate area (3), a paper-insulated cable (6), a lead wire bracket (10), and a riser (9) arranged sequentially at the end of the high voltage winding (1); The end of the high voltage winding (1) is led out through the winding main line (2), passes through the pressure plate area (3), and is provided with a shielded electrode section (4) between it and the paper-insulated cable (6). When the winding primary wire (2) passes through the pressure plate area (3), a first-level multi-layer corrugated cardboard (5) is provided for oil gap segmentation; The winding primary wire (2) is led out of the pressure plate area (3) and connected to the paper-insulated cable (6). The paper-insulated cable (6) is fixed by the wire clamp (7) at the lead wire bracket (10). A secondary multi-layer corrugated cardboard (8) is provided between the paper-insulated cable (6) and the wire clamp (7). The secondary multi-layer corrugated cardboard (8) is set beyond the lower equalizing ring of the riser (9).

2. The high-voltage winding end lead insulation structure according to claim 1, characterized in that, The shielding electrode segment (4) includes cotton thread (41), aluminum foil crepe paper (42) and shielding wire (43); after the winding primary wire (2) is arranged in a rectangular shape, it is filled with cotton thread (41) to form a circular or elliptical structure, and aluminum foil crepe paper (42) is wrapped around the outside of the circular or elliptical structure. The shielding wire (43) is embedded inside the aluminum foil crepe paper (42) and is pressed at the same potential as the winding primary wire (2).

3. The high-voltage winding end lead insulation structure according to claim 1, characterized in that, The pressure plate area (3) is also provided with an additional insulation at the first-level multi-layer corrugated cardboard (5). The first-level multi-layer corrugated cardboard (5) and the additional insulation are wrapped around the outside of the winding primary wire (2) at intervals, and several binding straps are tied at both ends of the wrapping structure to ensure tightness.

4. The high-voltage winding end lead insulation structure according to claim 1, characterized in that, The crimped area between the winding primary wire (2) and the paper-insulated cable (6) is wrapped with semiconductor crepe paper for electrode shielding; after the insulation is removed from the connection end of the paper-insulated cable (6), a bevel is formed, and the bevel and the winding primary wire (2) are wrapped together with heat-resistant crepe paper.

5. The high-voltage winding end lead insulation structure according to claim 4, characterized in that, The wrapping height of the heat-resistant crepe paper is 8 to 10 times the thickness of the paper-insulated cable (6). After the crimping area is wrapped with insulation, a layer of corrugated cardboard is also tied to the outside. The corrugated cardboard is an extension of a layer of a secondary multi-layer corrugated cardboard (8).

6. The high-voltage winding end lead insulation structure according to claim 4, characterized in that, The winding primary wire (2) is led out of the pressure plate area (3) and then connected to the paper-insulated cable (6) through the cold wire connector.

7. The high-voltage winding end lead insulation structure according to claim 1, characterized in that, The secondary multi-layer corrugated cardboard (8) between the conductor clamp (7) and the paper-insulated cable (6) is arranged in an intermittent manner to achieve oil gap separation insulation.

8. The high-voltage winding end lead insulation structure according to claim 1, characterized in that, The secondary multi-layer corrugated cardboard (8) extends beyond the height of the equalizing ring at the bottom of the riser seat (9) to meet the insulation withstand voltage requirements of the riser seat (9) area.

9. A method for insulating the end leads of a high-voltage winding, characterized in that, The high-voltage winding end lead insulation structure according to any one of claims 1-8 includes the following process: Lead out the primary winding (2) from the high voltage winding (1), perform shielding electrode treatment on the primary winding (2), arrange the primary winding (2) into a rectangle, fill it into a circle or ellipse with cotton thread (41), wrap it with aluminum foil crepe paper (42) and pre-embed shielding wire (43), so that the shielding wire (43) is pressed into the primary winding (2) at the same potential to form a shielding electrode section (4). The winding primary wire (2) with shielded electrode section (4) is passed through the pressure plate area (3), and wrapped with a first-level multi-layer corrugated cardboard (5) and an insulating spacer in the passing area. The two ends are tied with (2) binding tapes, and the oil gap is divided by the first-level multi-layer corrugated cardboard (5). The winding primary wire (2) is crimped with the paper-insulated cable (6), and after the crimped joint is tidied, a semiconductor crepe paper shield is wrapped around it. The insulation of the paper-insulated cable (6) is removed to form a bevel, and heat-resistant crepe paper is wrapped around it together with the winding primary wire (2). A layer of corrugated cardboard is tied to the outside. Pass the paper-insulated cable (6) through the lead wire bracket (10) and fix it with the wire clamp (7). Set a secondary multi-layer corrugated cardboard (8) between the paper-insulated cable (6) and the wire clamp (7) to divide the oil gap. A secondary multi-layer corrugated cardboard (8) is provided between the paper-insulated cable (6) and the conductor clamp (7) to ensure that the height of the multi-layer corrugated cardboard (8) exceeds the lower equalizing ring of the riser (9) to complete the overall insulation protection.

10. A transformer, characterized in that, It includes an iron core (14), a low-voltage winding (11), a high-voltage winding (1), a voltage regulating winding (12), and a balancing winding (13) arranged from the inside out; the high-voltage winding (1) is provided with the high-voltage winding end lead insulation structure as described in any one of claims 1-8.

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