Direct-current transformer for power distribution network

Abstract

The invention relates to the technical field of direct-current transformers, in particular to a direct-current transformer for a power distribution network, which comprises an iron core, a coil and insulating oil, an insulating assembly is arranged between the coil and the iron core, and the insulating assembly comprises an insulating paperboard, an insulating cushion block, an insulating contour semi-ring and a semi-ring groove, the insulating paper board is of a structure with a round inner wall and an octagonal outer wall. Through the unique design of the insulating paperboards, the insulating partition strips and the insulating partition blocks, the longitudinal oil ducts and the transverse oil ducts are effectively reserved, the oil flow path of the transformer is optimized, the cooling efficiency is improved, and stable operation of the transformer is ensured; through the bisection splicing structure of the insulating cardboard and the overturning action of the insulating parting strip, the quick clamping assembly of the insulating cardboard and the iron core is realized, the time for adapting the winding on site is saved, the tightness and uniformity of the winding are improved, and the reliability and safety of the transformer are enhanced.

Description

Technical Field

[0001] The present invention relates to the technical field of direct current transformers, and in particular to a direct current transformer for a power distribution network. Background Art

[0002] The DC transformer used in distribution networks, also known as a DC converter, is an electronic device that can convert the voltage of direct current. It plays a key role in distribution networks, mainly used to convert and stabilize DC power to meet the voltage requirements of different loads. It uses the magnetic flux lines (magnetic field) in the circuit to perform voltage conversion. When DC current passes through the input winding, the magnetic field generated will pass through the magnetic core, inducing an electromotive force in the output winding, thereby achieving voltage conversion and transmitting electrical energy to long-distance locations through high-voltage DC transmission lines.

[0003] A DC transformer consists of components such as an iron core, windings, an oil tank, insulating oil, an oil pillow, and insulating material separating the core and windings. The iron core, as the core of the magnetic circuit, conducts magnetic flux and supports the windings. The oil tank, filled with insulating oil, provides insulation and cooling. The insulating oil dissipates heat generated by the equipment. The oil pillow regulates the oil level and maintains a stable oil pressure. These components work together to maintain the operation of the DC transformer. The windings form the electrical circuit, responsible for the input and output of electrical energy. To prevent electrical short circuits, ensure proper current flow, and protect the windings from mechanical or electrical influences of the iron core, insulating material is added between the core and windings. Large-capacity transformer windings typically use a multi-turn spiral arrangement, with each layer of conductor spirally wound along the axis of the core or the previous layer. This winding arrangement maximizes internal space within the transformer and increases the winding fill rate. However, multi-turn spiral windings have a complex oil channel structure, which reduces the gaps through which the insulating oil can enter, obstructing heat dissipation and preventing the insulating oil from fully contacting the winding surface. In order to allow the insulating oil to smoothly enter the copper wires and assist the equipment in dissipating heat, after the coil winding work is completed, oil gap support bars will be driven between the windings to tighten the high-voltage winding. The copper wires will naturally tend to be straightened, forming longitudinal oil channels between the windings to avoid the problem of poor oil flow.

[0004] In power distribution scenarios requiring high capacity and high voltage, the thickness and number of insulating materials (typically insulating paper made from pure sulfate wood pulp) must be increased to further enhance the electrical insulation between the windings and the core. Furthermore, the insulation materials between layers, turns, and segments must be aligned during winding, and the spacing between each turn is strictly controlled by the winding machine. However, during the coil winding process, the winding machine cannot pre-reserve space for the oil gap stays (which can lead to a loose winding structure). After the oil gap stays are driven in, the copper wires are subjected to additional tensile stress, which not only causes fatigue damage to the copper wires over long-term use, but also disrupts the uniformity of the coil layer spacing, turn spacing, and segment spacing. Directly driving the oil gap stays in during the coil winding process interferes with the normal winding process, becoming a physical obstacle to coil formation. In addition, the addition of the oil gap support bar only forms a longitudinal oil channel, and the transverse heat dissipation channel of the multi-turn spiral winding is still blocked. Therefore, the insertion of the oil gap support bar cannot completely solve the problem of poor oil flow, and will also affect the stability of the coil structure.

[0005] Therefore, a DC transformer for distribution network is proposed. Summary of the Invention

[0006] The purpose of the present invention is to provide a DC transformer for a distribution network. In order to solve the problems of interference with winding, affecting the stability of the coil structure and failing to completely solve the heat dissipation and oil flow caused by the addition of oil gap supports in distribution scenarios where large capacity and high voltage need to be handled, longitudinal and transverse oil channels are reserved for the coil during winding through an insulating assembly, ensuring that the winding is tightly and evenly wound on the iron core.

[0007] To achieve the above object, the present invention provides the following technical solutions:

[0008] A DC transformer for a power distribution network includes an iron core, a coil, and insulating oil. An insulating assembly is provided between the coil and the iron core. The insulating assembly includes an insulating cardboard, an insulating spacer, an insulating profile semi-ring, and a semi-ring groove. The insulating cardboard has a circular inner wall and an octagonal outer wall. The insulating spacer is mounted on the edge of the insulating cardboard, and the insulating spacer is evenly arranged circumferentially on the outer wall of the insulating cardboard. Each insulating spacer is equipped with two insulating spacers, and the side surfaces of the insulating spacers are evenly distributed with insulating spacers. The insulating profile semi-ring is embedded and installed inside the insulating cardboard. The inner end of each insulating spacer passes through the insulating cardboard and contacts the insulating profile semi-ring. The semi-ring groove extends through the interior of the insulating profile semi-ring.

[0009] The insulating cardboard separating the iron core and the coil is wrapped around the surface of the iron core through an insulating contour semi-ring. In the horizontal direction, the copper wires of the coil are separated by insulating spacers and are parallel to each other and form a longitudinal oil channel. In the vertical direction, the copper wires of the coil are separated by insulating spacers and are parallel to each other and form a transverse oil channel. The longitudinal oil channel and the transverse oil channel are the oil flow paths of the insulating oil.

[0010] The above solution demonstrates that existing technologies use flat insulating cardboard and simple spacers to isolate the core and coils, resulting in a single oil channel design. In contrast, this solution utilizes the circular inner wall and octagonal outer wall structure of the insulating cardboard, combined with insulating spacers, insulating strips, and spacers, to form a complex insulation assembly. This not only tightly wraps the core but also creates longitudinal and transverse oil channels, optimizing the oil flow path, enhancing the transformer's heat dissipation capacity, improving structural stability and insulation performance, and ensuring tight and uniform coil winding, providing a more efficient and reliable solution for DC transformers used in distribution networks.

[0011] Preferably, the insulating paperboard is a two-part spliced ​​structure, and the two groups of insulating strips, insulating pads, insulating spacers and insulating contour semi-rings are symmetrically distributed with the cutting surface as the center plane, and the insulating strips, insulating pads, insulating spacers and insulating contour semi-rings are all made of zirconia ceramic material.

[0012] The above solution demonstrates that existing technologies typically employ monolithic insulating cardboard. In contrast, this solution utilizes a bisected, spliced ​​insulating cardboard structure, along with insulating strips, insulating pads, insulating spacers, and insulating contour half-rings constructed from zirconia ceramic material. The spliced ​​structure promotes uniformity in the winding process, ensuring the copper wire is wound evenly around the core, enhancing the transformer's flexibility. Zirconia ceramic material exhibits excellent insulation and high-temperature resistance, enhancing insulation effectiveness and service life, while also improving the transformer's overall safety and reliability. This provides a superior, more reliable insulation solution for DC transformers used in distribution networks.

[0013] Preferably, the insulating spacer includes a connecting block, a U-shaped groove and a U-shaped rod, the inner end of the connecting block is connected to the insulating contour half ring, the U-shaped groove is opened at the outer end of the connecting block, and the U-shaped groove matches the insulating spacer.

[0014] From the above solution, it can be seen that the existing technology uses simple block or strip-shaped insulating spacers, which lack a matching design with components such as insulating spacers. In contrast, the insulating spacers in this technical solution are uniquely designed, including a connecting block, a U-shaped groove and a U-shaped rod, where the U-shaped groove matches the insulating spacers. This design allows the insulating spacers and other components to fit tightly together, improving the stability and reliability of the insulation structure. In addition, this structure is also conducive to the flow of insulating oil and optimizes heat dissipation performance. Therefore, this solution has significant advantages in improving the overall performance and reliability of the transformer.

[0015] Preferably, the U-shaped rod is installed on the inner side of the U-shaped groove, and both ends of the U-shaped rod are connected to the side end surfaces of the U-shaped groove. The U-shaped rod has a structure with one end longer than the other end.

[0016] It can be seen from the above scheme that the existing technology will adopt a design without a U-shaped rod or a U-shaped rod with an equal length structure. Such a design will not be stable enough when fixing and supporting the insulating spacers. In contrast, the U-shaped rod in this technical solution is installed on the inner side of the U-shaped groove, and has a structure with one end long and the other end short. This design can better adapt to the shape and position of the insulating spacers and provide more stable support and fixation. At the same time, the design of U-shaped rods of different lengths can also adjust the position of the insulating spacers to a certain extent, thereby improving the flexibility and reliability of the insulation structure. Therefore, this solution has obvious advantages in enhancing the stability and flexibility of the transformer insulation structure.

[0017] Preferably, a sliding groove is provided at the bottom end of the insulating spacer, and the size of the sliding groove matches the U-shaped rod.

[0018] The above solution demonstrates that existing technologies often employ simple fixing methods, such as direct gluing or bolting, to the insulating spacers, lacking the flexibility to adjust and adapt to varying installation conditions. In contrast, the present invention incorporates sliding slots at the bottom of the insulating spacers that mate with the U-shaped rods. This design allows the insulating spacers to slide and adjust their position on the U-shaped rods, providing greater flexibility to accommodate varying coil winding requirements and installation conditions. This not only improves the installation convenience of the insulating spacers but also helps optimize the oil flow path and heat dissipation, enhancing the overall performance and reliability of the transformer.

[0019] Preferably, a movable sleeve is sleeved at the long end of the U-shaped rod, and a connecting rod is installed on one side surface of the movable sleeve. Two connecting rods are provided, and the two connecting rods are staggered with the U-shaped rod. A connecting spring is sleeved on the surface of the connecting rod, and the two ends of the connecting spring are respectively connected to the side surface of the movable sleeve and the end face of the U-shaped groove.

[0020] It can be seen from the above scheme that the existing technology uses a fixed connection method to fix the insulating spacers, which lacks the ability to adjust and buffer. In contrast, in this technical solution, the long end of the U-shaped rod is sleeved with a movable sleeve, and the movable sleeve is connected to the end face of the U-shaped groove through a sleeve rod and a sleeve spring. This design allows the insulating spacers to be fine-tuned during the installation process to adapt to different installation environments and coil winding requirements. At the same time, the sleeve spring provides a buffering effect, which can reduce the loosening or damage of the insulating spacers caused by vibration or thermal expansion and contraction, thereby improving the stability and reliability of the transformer. This solution performs well in enhancing the adaptability and protection of the insulating spacers.

[0021] Preferably, an outer ring wall surface inside the semi-ring groove is provided with an accommodating groove, the accommodating groove corresponds to the insulating spacer block one-to-one, and a pressing block is provided inside the accommodating groove.

[0022] It can be seen from the above scheme that the existing technology uses a simple fixing method to install the insulating spacer, which lacks precise control and fixation of the position of the insulating spacer. In contrast, the present technical solution opens a receiving groove corresponding to the insulating spacer on the outer ring wall inside the semi-ring groove, and provides a pressure block inside the receiving groove. This design can accurately control the position of the insulating spacer, ensure the close fit between the insulating spacer and the insulating contour semi-ring, and improve the stability and reliability of the insulation structure. At the same time, the presence of the pressure block can also effectively prevent the insulating spacer from shifting during use, further enhancing the insulation effect. This solution has significant advantages in improving the stability and accuracy of the transformer insulation structure.

[0023] Preferably, one end of the sleeve rod passes through the connecting block and is connected to the inner end surface of the pressing block. The outer end of the pressing block is provided with a rounded surface, and the rounded surface of the pressing block abuts against the outer surface of the rubber airbag.

[0024] It can be seen from the above scheme that the existing technology will adopt a direct fixation of the pressure block or other simple connection methods, which lacks precise control over the position and force of the pressure block. In contrast, in this technical solution, one end of the sleeve rod passes through the connecting block and is connected to the pressure block, and a rounded surface is provided on the outer end of the pressure block to abut against the outer surface of the rubber airbag. This design not only achieves a stable connection between the pressure block and the insulating pad, but also provides a buffering and sealing effect through the rubber airbag. The rounded surface design of the pressure block reduces the friction with the rubber airbag and extends the service life. This solution can accurately control the pressure of the pressure block on the insulating pad, improve the stability of the insulation structure, and at the same time enhance the sealing, prevent the leakage of insulating oil, and improve the overall performance of the transformer.

[0025] Preferably, a rubber airbag is provided inside the semi-annular groove, one end opening of the semi-annular groove is movably provided with a movable arc block, and the other end opening of the semi-annular groove is fixedly installed with a positioning blocking block, and the rubber airbag is filled between the positioning blocking block and the movable arc block.

[0026] It can be seen from the above solution that the existing technology uses simple seals or fillers to seal the semi-ring groove, but lacks adaptability and sealing. In contrast, the present technical solution sets a rubber airbag inside the semi-ring groove, and fixes and seals it through movable arc blocks and positioning sealing blocks. This design not only improves the sealing of the semi-ring groove and prevents leakage of insulating oil, but also effectively buffers the pressure changes between the insulating gasket and the insulating contour semi-ring through the elastic adaptability of the rubber airbag, reducing the risk of sealing failure caused by temperature changes or mechanical vibrations. This solution excels in improving the stability and sealing of the transformer insulation structure, and helps to improve the overall performance and reliability of the transformer.

[0027] Preferably, the two groups of movable arc blocks and positioning and blocking blocks are in opposite positions, and the movable arc blocks abut against the positioning and blocking blocks at corresponding positions.

[0028] It can be seen from the above scheme that the existing technology uses a single movable or fixed blocking block to close the semi-annular groove, which lacks flexibility and adaptability. In contrast, the present technical solution uses two sets of movable arc blocks and positioning blocking blocks in opposite positions, and the movable arc blocks abut against the positioning blocking blocks in corresponding positions. This design not only achieves the complete closure of the semi-annular groove, but also allows the position and strength of the blocking block to be adjusted within a certain range through the flexibility of the movable arc block to adapt to different installation conditions and environmental changes. This design improves the adaptability and sealing of the transformer insulation structure, reduces the risk of insulating oil leakage due to improper installation or environmental changes, and thus improves the overall performance and reliability of the transformer.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] 1. A DC transformer for distribution networks, with an octagonal design of insulating paperboard and the arrangement of several groups of insulating spacers and insulating blocks, creates uniform gaps between the copper wires in the coils in both the horizontal and vertical directions, forming longitudinal and transverse oil passages, respectively. This optimizes the circulation channels for the insulating oil, allowing the oil to flow more smoothly through the gaps in the windings, removing the heat generated. This not only improves cooling efficiency but also helps maintain stable operation of the transformer and extend its service life.

[0031] 2. A DC transformer for distribution networks uses a bisected insulation cardboard structure. Combined with the flipping action of the insulation spacers, this allows for on-site, adaptive installation of the core and windings. This avoids physical obstacles after coil formation and simplifies the winding installation process. Furthermore, the locking action of the insulating half-ring reduces the need for subsequent binding fixtures, significantly reducing the transformer's manufacturing cost and weight.

[0032] 3. A DC transformer for distribution networks. The insulation assembly, including the insulating cardboard, insulating spacers, insulating pads, insulating spacers, and insulating half-rings, is constructed from zirconia ceramic, a material with exceptional hardness and excellent insulation properties. These components not only effectively isolate the iron core from the coils and copper wires, preventing electrical short circuits, but also provide solid mechanical support for the entire coil, ensuring the windings are tightly and evenly wound around the core. This reduces magnetic flux leakage and losses, and improves the transformer's reliability and safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 This is a schematic diagram of the overall installation structure of the coil of the present invention;

[0034] Figure 2 This is a schematic diagram of the overall internal plan of the present invention;

[0035] Figure 3 Schematic diagram of the assembly structure of the coil and insulation assembly of the present invention;

[0036] Figure 4 Schematic diagram of the overall structure of the insulation assembly of the present invention;

[0037] Figure 5 Schematic diagram of the disassembled structure of the insulation assembly of the present invention;

[0038] Figure 6 This is a schematic diagram of the split structure of the insulating contour half ring of the present invention;

[0039] Figure 7 It is a schematic diagram of the inner plane of the insulating contour half ring of the present invention;

[0040] Figure 8 It is a schematic internal plan view of the insulating spacer of the present invention.

[0041] In the figure: 1. outer box shell; 2. oil tank shell; 3. oil pillow; 4. iron core; 5. lower clamp; 6. coil; 7. upper clamp; 8. insulation assembly; 81. insulation cardboard; 82. insulation spacer; 821. sliding sleeve groove; 83. insulation pad; 831. connecting block; 832. U-shaped groove; 833. U-shaped rod; 834. movable sleeve; 835. sleeve rod; 836. sleeve spring; 84. insulation spacer; 85. insulation contour semi-ring; 86. semi-ring groove; 861. rubber airbag; 862. movable arc block; 863. positioning blocking block; 864. receiving groove; 865. pressure block; 9. insulating oil. DETAILED DESCRIPTION

[0042] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0043] See also Figures 1 to 8 The present invention provides a DC transformer for a distribution network, and the technical solution is as follows:

[0044] A DC transformer for a distribution network includes an outer box shell 1, an oil tank shell 2, an oil pillow 3, an iron core 4, a lower clamp 5, a coil 6, an upper clamp 7, and insulating oil 9. The oil tank shell 2 is arranged on the inner side of the outer box shell 1, the oil pillow 3 is installed at the upper end of the outer box shell 1, the iron core 4 is located inside the oil tank shell 2, the upper clamp 7 and the lower clamp 5 are respectively arranged at the upper and lower ends of the iron core 4, the coil 6 is wound on the surface of the iron core 4, and the insulating oil 9 is filled in the interior of the oil tank shell 2. An insulating assembly 8 is provided between the coil 6 and the iron core 4. The insulating assembly 8 includes an insulating cardboard 81, an insulating spacer 83, an insulating contour semi-ring 85, and a semi-ring groove 86. The insulating cardboard 81 is fitted and connected to the iron core 4. The insulating The cardboard 81 has a circular inner wall and an octagonal outer wall. The insulating spacers 83 are installed at the ridgelines of the insulating cardboard 81. Twenty-four insulating spacers 83 are evenly arranged circumferentially on the outer wall of the insulating cardboard 81, forming a three-layer evenly divided structure. Each insulating spacer 83 is equipped with two insulating spacers 82. One end of the insulating spacer 82 is in contact with the surface of the insulating spacer 83. Insulating spacers 84 are evenly distributed on the side surfaces of the insulating spacers 82. An insulating contour semi-ring 85 is embedded in the interior of the insulating cardboard 81. The inner end of each insulating spacer 83 passes through the insulating cardboard 81 and is in contact with the insulating contour semi-ring 85. A semi-ring groove 86 is provided through the interior of the insulating contour semi-ring 85.

[0045] The insulating cardboard 81 that isolates the iron core 4 and the coil 6 is wrapped around the surface of the iron core 4 through an insulating contour half ring 85. The copper wires of the coil 6 in the horizontal direction are separated by insulating spacers 82 and are parallel to each other and form a longitudinal oil channel. The copper wires of the coil 6 in the vertical direction are separated by insulating spacers 84 and are parallel to each other and form a transverse oil channel. The longitudinal oil channel and the transverse oil channel are the oil flow paths of the insulating oil 9.

[0046] In this embodiment, when the transformer is powered on, current flows through coil 6, generating alternating magnetic flux in the core 4. This flux passes through coil 6, inducing an electromotive force in coil 6 according to the principle of electromagnetic induction, thus achieving voltage conversion. Insulating paper is wrapped layer by layer during the winding process to prevent electrical short circuits. Its porosity and electrostatic effects absorb impurities in the oil, protecting the winding from contamination. Insulating oil 9, the primary cooling and insulating medium, fills the transformer's oil tank 2, surrounding the core 4 and coil 6. As the transformer generates heat during operation, the insulating oil 9, through a thermal cycle, removes the heat and dissipates it to the outside, ensuring that the transformer temperature remains within a safe range. The oil pillow 3 plays a crucial role in regulating the oil level and reducing oil-air contact during transformer operation. When the oil temperature rises and its volume expands, the pillow 3 absorbs excess oil. When the oil temperature drops and its volume shrinks, the pillow 3 releases oil back into the tank 2, thereby maintaining a stable oil level within the tank 2 and reducing oxidation of the insulating oil 9, extending its lifespan.

[0047] As an embodiment of the present invention, refer to Figure 1 、 Figure 2 、 Figure 4 as well as Figure 5 The insulating paperboard 81 is a two-part splicing structure, and the two groups of insulating strips 82, insulating pads 83, insulating spacers 84 and insulating contour semi-rings 85 are symmetrically distributed with the cutting surface as the center plane, and the insulating strips 82, insulating pads 83, insulating spacers 84 and insulating contour semi-rings 85 are all made of zirconia ceramic material.

[0048] In this embodiment, the zirconia ceramic material has high hardness and extremely strong insulation properties, and can be used as the insulation material of the transformer. The insulating spacers 82, insulating pads 83, insulating spacers 84 and insulating contour half rings 85 are not only used to isolate the iron core 4 and the coil 6 and the electrical isolation between the copper wires, but also provide mechanical support for the entire coil 6. The entire insulating paperboard 81 is wrapped on the surface of the iron core 4 through the insulating contour half ring 85. The insulating spacers 82, insulating pads 83, insulating spacers 84 and insulating contour half rings 85 are relatively small in size and still use the insulating paperboard 81 as the main body. They can replace the large number of bundled and fixed connectors used after winding and forming, which is beneficial to reducing the weight and volume of the equipment and saving the equipment manufacturing cost.

[0049] As an embodiment of the present invention, refer to Figures 1-4 The insulating spacer 83 includes a connecting block 831, a U-shaped groove 832 and a U-shaped rod 833. The inner end of the connecting block 831 is connected to the insulating contour half ring 85. The U-shaped groove 832 is opened at the outer end of the connecting block 831. The U-shaped rod 833 is installed on the inner side of the U-shaped groove 832. The two ends of the U-shaped rod 833 are connected to the side end faces of the U-shaped groove 832. The U-shaped rod 833 has a structure with one end long and the other end short. The U-shaped groove 832 matches the insulating spacer 82.

[0050] In this embodiment, in order to avoid interfering with the winding work and causing physical obstacles and other problems, before the coil 6 is formed, the insulating spacer 82 is located at the lower end of the insulating pad 83. When the copper wire winding work begins, the insulating spacer 82 is flipped one by one, and the copper wire is wound layer by layer until the coil 6 is formed as a whole.

[0051] As an embodiment of the present invention, refer to Figure 7 A sliding sleeve groove 821 is formed at the bottom end of the insulating spacer 82 , and the size of the sliding sleeve groove 821 matches the U-shaped rod 833 .

[0052] In this embodiment, the insulating spacer 82 can be slidably connected with the U-shaped rod 833 through the sliding groove 821, assisting the flipping of the insulating spacer 82 and limiting the displacement of the insulating spacer 82 so that when it flips to the upper end of the insulating pad 83, it can always remain parallel to the insulating paper board 81.

[0053] As an embodiment of the present invention, refer to Figure 7 and Figure 8 The long end of the U-shaped rod 833 is sleeved with a movable sleeve 834, and a sleeve rod 835 is installed on one side surface of the movable sleeve 834. There are two sleeve rods 835, which are staggered with the U-shaped rod 833. A sleeve spring 836 is sleeved on the surface of the sleeve rod 835, and the two ends of the sleeve spring 836 are respectively connected to the side surface of the movable sleeve 834 and the end face of the U-shaped groove 832.

[0054] In this embodiment, when the first insulating spacer 82 flips to the upper end of the insulating pad 83, the insulating spacer 82 squeezes the movable sleeve 834, the sleeve spring 836 is compressed, and the movable sleeve 834 pushes the pressure block 865 to move along the accommodating groove 864 through the sleeve rod 835. Therefore, whenever the insulating spacer 82 flips, it means the beginning of the copper wire winding work, and the weight of the coil 6 will gradually be applied to the entire insulating assembly 8. Therefore, the up and down flipping of the insulating spacer 82 controls the jamming and disassembly of the insulating contour half ring 85.

[0055] As an embodiment of the present invention, refer to Figure 7 and Figure 8The outer ring wall inside the semi-ring groove 86 is provided with an accommodating groove 864 , which corresponds one-to-one to the insulating spacer 83 , and a pressing block 865 is provided inside the accommodating groove 864 .

[0056] In this embodiment, four receiving grooves 864 are opened on the inner side of a semi-annular groove 86, and four pressure blocks 865 are accommodated inside the four receiving grooves 864. When the four pressure blocks 865 move at the same time, the rubber airbag 861 is squeezed and compressed by the four pressure blocks 865 at the same time.

[0057] As an embodiment of the present invention, refer to Figure 8 One end of the sleeve rod 835 passes through the connecting block 831 and is connected to the inner end surface of the pressing block 865. The outer end of the pressing block 865 is provided with a rounded surface, and the rounded surface of the pressing block 865 abuts against the outer surface of the rubber airbag 861.

[0058] In this embodiment, the rounded surface of the pressing block 865 is utilized to prevent the surface of the rubber airbag 861 from being damaged even after being squeezed, thereby increasing the service life of the rubber airbag 861.

[0059] As an embodiment of the present invention, refer to Figure 6 and Figure 7 A rubber airbag 861 is provided inside the semi-annular groove 86, and a movable arc block 862 is movably provided at one end opening of the semi-annular groove 86, and a positioning blocking block 863 is fixedly installed at the other end opening of the semi-annular groove 86. The rubber airbag 861 is filled between the positioning blocking block 863 and the movable arc block 862.

[0060] In this embodiment, the positioning blocking block 863 is set to a fixed state and the movable arc block 862 is set to a movable state. The purpose is to limit the deformation direction of the rubber airbag 861 so that only the position of the movable arc block 862 of the rubber airbag 861 can be displaced, so that a part of the movable arc block 862 enters the opening of the semi-ring groove 86 at the corresponding position, thereby realizing the locking operation of the two insulating contour semi-rings 85.

[0061] As an embodiment of the present invention, refer to Figure 8 The two groups of movable arc blocks 862 and positioning blocking blocks 863 are in opposite positions, and the movable arc blocks 862 abut against the positioning blocking blocks 863 at the corresponding positions.

[0062] In this embodiment, the two groups of movable arc blocks 862 and positioning blocking blocks 863 are arranged in opposite positions, the movable arc blocks 862 and positioning blocking blocks 863 of each insulating contour semi-ring 85 are in opposite positions, the deformation directions of the two rubber airbags 861 are also opposite, and the two movable arc blocks 862 are displaced at the same time and enter the openings of the semi-ring grooves 86 in opposite positions, thereby realizing the engagement operation of the two insulating contour semi-rings 85.

[0063] Working principle: The iron core 4 is wrapped with an insulating cardboard 81 divided into two halves, and copper wire is spirally wound on the insulating cardboard 81 to form a multi-layer coil 6. After each layer of coil 6 is formed, it is wrapped with a layer of insulating paper. The insulating spacer 82 is flipped over to not only shape the insulating paper, but also lock the two corresponding insulating contour half rings 85, so that the insulating cardboard 81 divided into two halves is wrapped on the iron core 4, completing the on-site adaptation installation of the winding and the iron core 4. The longitudinal and transverse oil channels are reserved by the setting of the insulating cardboard 81, the insulating spacer 82 and the insulating spacer block 84, which optimizes the oil flow path and provides good mechanical support to ensure that the winding is tightly and evenly wound.

[0064] Specifically, to address the issue of poor oil flow at the winding location inside the transformer tank, longitudinal and transverse oil channels were reserved in advance during the winding process of coil 6. This not only stabilizes the coil 6 structure and eliminates the need for a large number of binding fixtures after winding, but also reduces the volume and weight of the transformer, improves oil flow efficiency, and optimizes the overall transformer design. The winding improvement process is as follows:

[0065] First, the copper wire is spirally wound around the axial circumference of the insulating paperboard 81 through the insulating spacers 84 at the ridgeline position of the insulating paperboard 81, with the insulating spacers 84 as intervals to form the inner layer coil 6. After wrapping with a layer of insulating paper, eight insulating spacers 82 at the same horizontal position are flipped along the U-shaped rod 833 to the upper end of the connecting block 831. The copper wire is then repeatedly spirally wound around the outside of the inner layer coil 6 and wrapped with another layer of insulating paper to form the middle layer coil 6. The insulating spacers 82 are then flipped and the wound copper wire is repeatedly wrapped with a layer of insulating paper to form the outer layer coil 6.

[0066] Utilizing the octagonal surface of the outer contour of the insulating cardboard 81, the inner copper wire is wound in an octagonal direction. The middle and outer copper wires are spirally wound with insulating spacers 84 as intervals. The copper wires between two adjacent insulating spacers 83 are in a straightened state due to the absence of external force. The horizontal copper wires are parallel to each other due to the insulating spacers 82, with uniform gaps forming longitudinal oil channels. The vertical copper wires are parallel to each other due to the insulating spacers 84, with uniform gaps forming transverse oil channels. The longitudinal and transverse oil channels provide circulation channels for the insulating oil 9, remove the heat generated by the winding, optimize the oil flow path, improve the cooling efficiency, and help maintain stable operation of the transformer.

[0067] By utilizing the longitudinal and transverse oil channels, there are appropriate gaps between the wires of the winding in both the horizontal and vertical directions. Each time a layer of insulating paper is wrapped, the insulating spacer 82 is turned over and pressed against the surface of the insulating paper, which is conducive to promoting the shaping of the insulating paper, ensuring that the insulating material is arranged neatly, without applying too much insulating material, and maintaining good electrical performance.

[0068] In order to ensure that the winding can be tightly and evenly wound on the iron core 4, so that the magnetic flux can pass smoothly and reduce leakage and loss, in the distribution network transformer, prefabricated windings are abandoned and the iron core 4 and winding are adapted and installed on site. In order to avoid physical obstacles during the coil 6 forming process, the insulating cardboard 81 is divided into two equal parts, and the inner wall surface contour of the insulating cardboard 81 is designed to match the outer contour of the iron core 4. The separated insulating cardboards 81 are combined and wrapped around the circumference of the iron core 4. Then, by flipping the insulating spacer 82, the two connected insulating contour half rings 85 are locked, and the insulating cardboard 81 is then wrapped around the iron core 4. This eliminates the need for a large number of subsequent bundling fixtures and helps reduce the manufacturing cost of the transformer. The on-site adaptation process of the winding and coil 6 is as follows:

[0069] The separated insulating cardboard 81 is wrapped on the circumference of the iron core 4. When the inner copper wire is wound, the insulating spacer 82 is turned over. When the insulating spacer 82 slides horizontally along the upper U-shaped rod 833, it gradually squeezes the inner movable sleeve 834. The movable sleeve 834 pushes the pressing block 865 through the sleeve rod 835, and the rubber airbag 861 is squeezed. The original rubber airbag 861 is filled between the movable arc block 862 and the positioning blocking block 863. At the same time, the four pressing blocks 865 squeeze the rubber airbag 861. Since the positioning blocking block 863 is fixed inside the semi-annular groove 86, state, and the movable arc block 862 is in the active state, the rubber airbag 861 pushes the movable arc block 862 into the open end of the adjacent semi-annular groove 86, thereby completing the engagement, and the insulating contour semi-ring 85 and the insulating pad 83 are made of zirconia ceramic material, which has high hardness and excellent insulation, providing good mechanical support for the winding as a whole. The insulating paperboard 81 and the iron core 4 can be assembled by flipping the insulating spacer 82, which not only saves the time required for on-site adaptation of the winding, but also ensures that the winding can be tightly and evenly wound on the iron core 4, further improving the reliability and safety of the transformer.

[0070] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A DC transformer for a power distribution network, comprising an iron core (4), a coil (6) and insulating oil (9), characterized in that: An insulating assembly (8) is provided between the coil (6) and the iron core (4), and the insulating assembly (8) comprises an insulating paperboard (81), an insulating spacer (83), an insulating contour semi-ring (85), and a semi-ring groove (86). The insulating paperboard (81) is wrapped around the outer surface of the iron core (4), and the insulating paperboard (81) has a circular inner wall and an octagonal outer wall. The insulating spacer (83) is installed at the edge position of the insulating paperboard (81), and the insulating spacer (83) is evenly arranged in the circumferential direction. The outer wall surface of the edge paperboard (81), each of the insulating spacers (83) is equipped with two insulating spacers (82), the side surfaces of the insulating spacers (82) are evenly distributed with insulating spacers (84), the insulating contour semi-ring (85) is embedded and installed inside the insulating paperboard (81), the inner end of each insulating spacer (83) passes through the insulating paperboard (81) and is connected to the insulating contour semi-ring (85), and the semi-ring groove (86) is opened through the inside of the insulating contour semi-ring (85); The insulating paperboard (81) isolating the iron core (4) and the coil (6) and is attached to the surface of the iron core (4) through an insulating contour half ring (85). The copper wires of the coil (6) are separated by insulating spacers (84) in the vertical direction and are parallel to each other and form a transverse oil channel. The longitudinal oil channel and the transverse oil channel are oil flow paths for the insulating oil (9).

2. A DC transformer for a power distribution network according to claim 1, characterized in that: The insulating paperboard (81) is a bisected spliced ​​structure, and the two groups of insulating spacers (82), insulating spacers (83), insulating spacers (84) and insulating contour semi-rings (85) are symmetrically distributed with the cutting surface as the center plane, and the insulating spacers (82), insulating spacers (83), insulating spacers (84) and insulating contour semi-rings (85) are all made of zirconia ceramic material.

3. The DC transformer for a power distribution network according to claim 1, characterized in that: The insulating spacer (83) includes a connecting block (831), a U-shaped groove (832) and a U-shaped rod (833), wherein the inner end of the connecting block (831) is connected to the insulating profile half ring (85), and the U-shaped groove (832) is opened at the outer end of the connecting block (831), and the inner size of the U-shaped groove (832) matches the outer size of the insulating spacer (82).

4. A DC transformer for a power distribution network according to claim 3, characterized in that: The U-shaped rod (833) is installed inside the U-shaped groove (832), and both ends of the U-shaped rod (833) are connected to the side end surfaces of the U-shaped groove (832). The U-shaped rod (833) has a structure with one end longer and the other end shorter.

5. The DC transformer for a power distribution network according to claim 3, characterized in that: A sliding sleeve groove (821) is provided at the bottom end of the insulating spacer (82), and the size of the sliding sleeve groove (821) matches the U-shaped rod (833).

6. A DC transformer for a power distribution network according to claim 3, characterized in that: The long end of the U-shaped rod (833) is sleeved with a movable sleeve (834), and a sleeve rod (835) is installed on one side surface of the movable sleeve (834). Two sleeve rods (835) are provided, and the two sleeve rods (835) are staggered with the U-shaped rod (833). A sleeve spring (836) is sleeved on the surface of the sleeve rod (835), and the two ends of the sleeve spring (836) are respectively connected to the side surface of the movable sleeve (834) and the end surface of the U-shaped groove (832).

7. A DC transformer for a power distribution network according to claim 6, characterized in that: An accommodating groove (864) is provided on the outer ring wall surface inside the semi-ring groove (86), and the accommodating groove (864) corresponds one-to-one with the insulating spacer (83). A pressing block (865) is provided inside the accommodating groove (864).

8. A DC transformer for a power distribution network according to claim 7, characterized in that: One end of the sleeve rod (835) passes through the connecting block (831) and is connected to the inner end surface of the pressing block (865). The outer end of the pressing block (865) is provided with a rounded surface.

9. The DC transformer for a power distribution network according to claim 7, characterized in that: A rubber airbag (861) is provided inside the semi-annular groove (86), and the rounded surface of the pressing block (865) abuts against the outer surface of the rubber airbag (861). One end opening of the semi-annular groove (86) is movably provided with a movable arc block (862), and the other end opening of the semi-annular groove (86) is fixedly installed with a positioning blocking block (863), and the rubber airbag (861) is filled between the positioning blocking block (863) and the movable arc block (862).

10. A DC transformer for a power distribution network according to claim 9, characterized in that: The two groups of movable arc blocks (862) and positioning and blocking blocks (863) are located in opposite positions, and the movable arc blocks (862) abut against the positioning and blocking blocks (863) at corresponding positions.

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