Iron core structure and transformer

Abstract

This utility model discloses a core structure and a transformer, relating to the field of transformer technology. The core structure includes a three-dimensional wound core, windings, and fixing clamps. The three-dimensional wound core includes a core post and a yoke, with the windings wound around the core post. The fixing clamps include an upper clamp, a lower clamp, and a tie rod. Both the upper and lower clamps include a frame and pads. The frame comprises multiple non-magnetic steel plates joined end-to-end to form the frame, which is fitted onto the ends of the three-dimensional wound core. The yoke and part of the core post are fitted against the inner wall of the frame. The pads are connected to the frame and support the windings and yoke. The tie rods are used to pull the upper and lower clamps together. The core structure provided by this solution has the advantage of reducing eddy current losses in the transformer.

Description

Technical Field

[0001] This utility model relates to the field of transformer technology, and in particular to a core structure and a transformer. Background Technology

[0002] For large-capacity three-dimensional wound core transformers, their structural characteristics dictate a large volume of the core and coil windings. Simultaneously, the clamps, as key components for fixation and support, are also relatively large. Because the clamps are installed close to the winding ends, a large amount of leakage flux is generated around the windings during transformer operation. This leakage flux passes through the clamps, forming a closed magnetic circuit within them. According to the principle of electromagnetic induction, changes in magnetic flux within a closed magnetic circuit induce eddy currents, and the structural characteristics of the clamps make it easy for these eddy currents to form circulating currents. These circulating currents continuously flow inside the clamps, resulting in significant eddy current losses. This not only reduces the transformer's operating efficiency but may also affect its overall performance and stability. Utility Model Content

[0003] The main purpose of this invention is to propose a core structure and transformer that aims to reduce eddy current losses in the core structure.

[0004] To achieve the above objectives, this utility model proposes a core structure, comprising:

[0005] Three-dimensional coiled iron core, including core post and yoke;

[0006] The winding is wound around the core post;

[0007] The fixing clamp includes an upper clamp, a lower clamp, and a pull member. The upper clamp and the lower clamp each include a frame and a pad. The frame includes multiple non-magnetic steel plates, which are joined end to end to form the frame. The frame is sleeved on the end of the three-dimensional coiled iron core. The yoke and part of the core column are in contact with the inner wall of the frame. The pad is connected to the frame and is used to support the winding and the yoke. The pull member is used to pull the upper clamp and the lower clamp together.

[0008] In one embodiment, the inner wall of the frame encloses a receiving space for accommodating the yoke and part of the core column, and the non-magnetic steel plate has an oil guide hole that communicates with the receiving space.

[0009] In one embodiment, the upper clamp and the lower clamp further include a magnetic guide plate, which is mounted on the oil guide hole.

[0010] In one embodiment, the pad includes a base plate, a column, and a pressure plate. The base plate is mounted on the frame. The two ends of the column are connected to the base plate and the pressure plate, respectively. The top end of the winding abuts against the pressure plate in the upper clamp, and the bottom end of the winding abuts against the pressure plate in the lower clamp.

[0011] In one embodiment, the base plate includes three support plates arranged at a 120-degree angle, the support plates are connected to the frame and abut against the yoke, and the column is installed at the intersection of the three support plates.

[0012] In one embodiment, the three-dimensional coiled iron core includes three iron core frames, and the three-dimensional coiled iron core is formed by assembling the three iron core frames to form a triangular three-dimensional structure. The three-dimensional coiled iron core includes three core columns distributed in a triangular pattern.

[0013] The iron core frame includes an inner frame and an outer frame. The inner frame is made of cold-rolled silicon steel sheet, and the outer frame is made of amorphous alloy strip.

[0014] In one embodiment, a magnetic adhesive is coated between the cold-rolled silicon steel sheet and the amorphous alloy strip.

[0015] In one embodiment, the thickness of the inner frame is defined as d, and the thickness of the iron core frame is defined as D;

[0016] Therefore, d and D satisfy: 0.4≤d / D≤0.6.

[0017] In one embodiment, the winding includes an A-phase winding, a B-phase winding, and a C-phase winding. The leads of the A-phase winding, the B-phase winding, and the C-phase winding are spaced apart along the height direction of the core column. The core structure also includes a busbar group, which includes parallel A-phase lead copper busbars, B-phase lead copper busbars, C-phase lead copper busbars, and a zero-phase lead copper busbar. The A-phase lead copper busbar is parallel to the radial plane of the A-phase winding. The leads of the A-phase winding, the B-phase winding, and the C-phase winding are respectively connected to the A-phase lead copper busbar, the B-phase lead copper busbar, and the C-phase lead copper busbar. The neutral point of the A-phase winding, the B-phase winding, and the C-phase winding is connected to the zero-phase lead copper busbar.

[0018] This utility model also proposes a transformer, including the core structure as described in any of the above embodiments.

[0019] According to the technical solution of this utility model, the iron core structure includes a three-dimensional wound iron core, windings, and fixing clamps. The three-dimensional wound iron core includes a core post and a yoke, with the windings wound around the core post. The fixing clamps include an upper clamp, a lower clamp, and a tie rod. Both the upper and lower clamps include a frame and pads. The frame comprises multiple non-magnetic steel plates joined end-to-end to form a frame, which is fitted onto the ends of the three-dimensional wound iron core. The yoke and part of the core post are in contact with the inner wall of the frame. The pads are connected to the frame and support the windings and the yoke. The tie rods are used to pull the upper and lower clamps together. This arrangement allows the three-dimensional wound iron core with the windings to be clamped between the upper and lower clamps, thereby fixing the three-dimensional wound iron core and the windings. Based on this, by placing the frame formed by the non-magnetic steel plate around both ends of the three-dimensional wound core, the angle between the yoke and the core column can be shielded by the non-magnetic steel plate. This helps to reduce the eddy current losses in the upper and lower clamps caused by the leakage magnetic flux at the angle between the yoke and the core column. In addition, the frame formed by the non-magnetic steel plate can also partially block the closed magnetic circuit formed by the leakage magnetic flux of the winding, thereby further reducing the eddy current losses in the fixed clamps, which in turn helps to reduce the overall eddy current losses in the core structure. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0021] Figure 1 A schematic diagram of the structure of an embodiment of the iron core frame provided by this utility model;

[0022] Figure 2 A front structural diagram of an embodiment of the lower clamp provided by this utility model;

[0023] Figure 3 for Figure 2 A top view of the lower clamping component provided in the diagram;

[0024] Figure 4 This is a partial structural schematic diagram of an embodiment of the transformer provided by this utility model;

[0025] Figure 5 This is a schematic diagram of another part of an embodiment of the transformer provided by this utility model.

[0026] Explanation of icon numbers:

[0027] 1. Iron core frame; 11. Inner frame; 12. Outer frame; 13. Contact surface; 14. Grounding plate;

[0028] 2. Windings; 21. Phase A winding; 22. Phase B winding; 23. Phase C winding;

[0029] 3. Lower clamping component; 31. Frame; 311. Non-magnetic steel plate; 312. Oil guide hole; 32. Foot pad; 321. Base plate; 321a. Support plate; 322. Column; 323. Pressure plate;

[0030] 4. Busbar group; 41. Phase A copper busbar; 42. Phase B copper busbar; 43. Phase C copper busbar;

[0031] 5. Instrument box;

[0032] 6. Magnetic leakage compensator; 61. Sensor; 62. Connector; 63. Smart terminal.

[0033] The realization of the purpose, functional features and advantages of this utility model will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0034] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0035] It should be noted that if the embodiments of this utility model involve directional indicators (such as up, down, left, right, front, back, etc.), the directional indicators are only used to explain the relative positional relationship and movement of the components in a specific posture. If the specific posture changes, the directional indicators will also change accordingly.

[0036] Furthermore, if the embodiments of this utility model involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the use of "and / or" or "and / or" throughout the text includes three parallel solutions. For example, "A and / or B" includes solution A, solution B, or a solution where both A and B are satisfied simultaneously. Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this utility model.

[0037] In large-capacity three-dimensional wound transformers (such as those above 35KV), the core and coil windings must have sufficient volume to meet the power transmission capacity requirements due to the need to handle large power transmission and conversion tasks; therefore, both are relatively large. Meanwhile, the clamps, as an indispensable key component of the transformer's internal structure, play a crucial role in fixing and supporting the core and coil windings. To ensure that the core and coil windings maintain a stable relative position during transformer operation and prevent displacement due to vibration or external forces, the clamps need sufficient strength and size, which also makes their volume considerable.

[0038] To maintain the position of the coil windings and core, clamps are typically positioned near the winding ends. However, the applicant's research revealed that a significant amount of leakage flux is inevitably generated around the windings after the transformer is put into operation. Because the clamps are installed close to the winding ends, this leakage flux passes through the clamps, forming closed magnetic circuits within them. Changes in magnetic flux within these closed circuits inevitably induce eddy currents within the clamps. Furthermore, the relatively regular shape of the clamps makes it easy for these induced eddy currents to circulate. Once these circulating currents continue to flow within the clamps, they cause substantial eddy current losses. The presence of eddy current losses means that some electrical energy is wasted on the clamps instead of being used for normal power transmission and conversion, directly reducing the transformer's operating efficiency. More seriously, long-term eddy current losses can negatively impact the overall performance and stability of the transformer, such as causing localized overheating of the clamps, affecting their mechanical strength and service life, and potentially leading to more serious faults that threaten the safe and stable operation of the entire power system.

[0039] In view of this, the present invention proposes a core structure to solve or at least alleviate the above problems.

[0040] Please see Figures 1 to 5 In one embodiment of this utility model, the core structure includes a three-dimensional wound core, windings, and fixing clamps. The three-dimensional wound core includes a core post and a yoke, with the winding 2 wound around the core post. The fixing clamps include an upper clamp, a lower clamp 3, and a pull member. Both the upper and lower clamps 3 include a frame 31 and a foot 32. The frame 31 includes multiple non-magnetic steel plates 311 connected end-to-end to form the frame 31. The frame 31 is fitted onto the end of the three-dimensional wound core. The yoke and part of the core post are in contact with the inner wall of the frame 31. The foot 32 is connected to the frame 31 and supports the winding 2 and the yoke. The pull member is used to pull the upper clamp and the lower clamp 3 together.

[0041] Specifically, in this embodiment, the permeability of the non-magnetic baffle needs to be greater than 1.1. The non-magnetic steel plate 311 is made of either high-manganese non-magnetic steel or austenitic stainless steel. The non-magnetic steel plate 311 has a stable austenitic structure at room temperature. Austenite is a face-centered cubic crystal structure and exhibits paramagnetism, meaning it will only be magnetized very weakly in a magnetic field. In addition, the non-magnetic steel plate 311 also has a high resistivity. When placed in an alternating magnetic field, eddy currents will be generated inside the conductor according to the law of electromagnetic induction. The high resistivity makes the eddy currents generated in the non-magnetic steel plate 311 very small, and therefore the eddy current loss is also very small. Since the yoke and part of the core column in this embodiment can be fitted into the frame 31, most of the leakage flux generated by the yoke, the connection between the yoke and the core column, and the winding 2 cannot generate eddy current losses in the non-magnetic steel plate 311 due to the shielding effect of the non-magnetic steel plate 311. Therefore, the purpose of reducing eddy current losses in the core structure can be achieved.

[0042] It should be noted that when the frame 31 is formed by enclosing non-magnetic steel plates 311, its processing method can be either bending the non-magnetic steel plates 311 to form the frame 31, or welding multiple non-magnetic steel plates 311 to form the frame 31. The specific processing method can be selected according to design requirements. Furthermore, the connection method between the pad 32 and the frame 31 includes one of bolt connection and welding. The tie member includes one of rectangular plate, channel steel, and tie rod. The tie member is connected to the upper clamp and lower clamp 3 by threaded connection or welding to provide a counterforce to the upper clamp and lower clamp 3, enabling the upper clamp and lower clamp 3 to stably clamp the three-dimensional coiled iron core and winding 2. The tie member is connected to at least one of the pad 32 and the frame 31.

[0043] In this embodiment, the horizontal cross-section of the frame 31 is hexagonal, and the hexagon has a long side and a short side. The long side and the short side are alternately connected to form the hexagon. This structural form can be adapted to clamping the three-dimensional coiled iron core, so that the frame 31 can fit and clamp the three-dimensional coiled iron core along the extension direction of the iron yoke, thereby improving the stability of the three-dimensional coiled iron core during operation.

[0044] According to the technical solution of this embodiment, the three-dimensional wound iron core with the winding 2 installed can be clamped between the upper clamp and the lower clamp 3, thereby fixing the three-dimensional wound iron core and the winding 2. On this basis, by fitting the frame 31 formed by the non-magnetic steel plate 311 around both ends of the three-dimensional wound iron core, the angle between the yoke and the core column can be shielded by the non-magnetic steel plate 311, which helps to reduce the eddy current loss in the upper clamp and the lower clamp 3 caused by the leakage magnetic flux at the angle between the yoke and the core column. In addition, the frame 31 formed by the non-magnetic steel plate 311 can also partially block the closed magnetic circuit formed by the leakage magnetic flux of the winding 2, thereby further reducing the eddy current loss in the fixing clamp, and thus helping to reduce the overall eddy current loss in the iron core structure.

[0045] Please refer to the figure for further details. Figure 2 and Figure 3 In one embodiment of this utility model, the inner wall of the frame 31 encloses a receiving space for accommodating the yoke and part of the core column. The non-magnetic steel plate 311 has an oil guide hole 312, which communicates with the receiving space. For a three-dimensional wound core, the leakage magnetic flux at the yoke and the connection between the yoke and the core column is relatively large. Therefore, the yoke and the connection between the yoke and the core column are all housed within the receiving space, allowing the frame 31 to form a magnetic shielding structure for these parts, thereby reducing eddy current losses. The oil guide hole 312 in the non-magnetic steel plate 311 allows the frame 31 to form an oil passage, enabling transformer oil to flow into or out of the receiving space along the oil guide hole, ensuring the cooling efficiency of the yoke and the connection between the yoke and the core column. In this embodiment, the oil guide hole is rectangular and located on the long side of the frame 31. Besides allowing transformer oil to flow, the oil guide hole also provides operating space for installing bolts on the foot 32.

[0046] Furthermore, in one embodiment of this utility model, the upper clamp and lower clamp 3 also include a magnetic guide sheet, which is installed in the oil guide hole 312. The magnetic guide sheet is made of silicon steel and ferrite. The magnetic guide sheet is welded or embedded in the hole wall of the oil guide hole 312. By setting the magnetic guide sheet, a low magnetic resistance path can be provided for the leakage flux, so that the leakage flux closes along a preset low-loss path, thereby diverting the leakage flux from components such as the frame 31, pad 32, and bolts, which is beneficial to further reduce eddy current losses in the upper clamp and lower clamp 3.

[0047] Please see Figure 2 and Figure 3In one embodiment of this utility model, the pad 32 includes a base plate 321, a column 322, and a pressure plate 323. The base plate 321 is mounted on the frame 31. The two ends of the column 322 are connected to the base plate 321 and the pressure plate 323, respectively. The top end of the winding 2 abuts against the pressure plate 323 in the upper clamp, and the bottom end of the winding 2 abuts against the pressure plate 323 in the lower clamp 3. Specifically, the two base plates 321 in the upper and lower clamps 3 abut against the top and bottom ends of the three-dimensional coiled iron core, respectively, to provide a clamping effect on the three-dimensional coiled iron core. The column 322 supports the pressure plate 323, allowing the pressure plate 323 to abut against the top and bottom ends of the winding 2, thereby providing a clamping effect on the winding 2. In this way, the fixing effect of the three-dimensional coiled iron core and the winding 2 is more reliable and the positioning is more accurate. In other embodiments, an insulating pad is provided between the pressure plate 323 and the winding 2 to further improve the stability of the winding 2 during operation.

[0048] Please see Figure 3 In one embodiment of this utility model, the base plate 321 includes three support plates 321a arranged at a 120-degree angle. The support plates 321a are connected to the frame 31 and abut against the yoke. The column 322 is installed at the intersection of the three support plates 321a. This arrangement helps to reduce the material used in the base plate 321 and lower its material cost. In addition, using three support plates 321a to support the three yokes at the ends of the three-dimensional wound core can not only ensure the clamping effect of the three-dimensional wound core, but also facilitate the flow of transformer oil into the accommodating space, thereby improving the cooling efficiency of the yoke part.

[0049] Please see Figure 1In one embodiment of this utility model, the three-dimensional wound iron core includes three iron core frames 1, which are assembled to form a triangular three-dimensional structure. The three-dimensional wound iron core includes three core columns distributed in a triangular pattern. The iron core frame 1 includes an inner frame 11 and an outer frame 12. The inner frame 11 is wound from cold-rolled silicon steel sheets, and the outer frame 12 is wound from amorphous alloy strips. The portion of the iron core frame 1 used for winding the winding 2 is the sub-column. Two adjacent sub-columns in two iron core frames 1 are joined to form one core column. Since adjacent iron core frames 1 have the same size and shape, the three core columns are distributed in an equilateral triangle. The portion of the iron core frame 1 connected to the sub-column is the yoke. When the iron core frames 1 are joined, the joint between two adjacent yokes is filled with magnetic adhesive to reduce magnetic leakage flux at the yoke joint. The magnetic adhesive includes one of epoxy resin magnetic adhesive and silicone magnetic adhesive. In this embodiment, the core frame 1 is formed by winding cold-rolled silicon steel sheets and amorphous alloy strips. Cold-rolled silicon steel sheets have the advantage of high saturation magnetic flux density, while amorphous alloy strips can reduce the no-load loss of the transformer. Using these two types of strips to make the core frame 1 effectively combines the characteristics of the two materials, which is beneficial for reducing the operating noise of the transformer and preventing amorphous oversaturation. This allows the transformer to operate under higher magnetic flux density conditions than ordinary amorphous transformers, thereby reducing the size of the transformer. In other embodiments, the core frame 1 includes an inner frame 11, a middle frame, and an outer frame 12. The inner frame 11 and the outer frame 12 are both formed by winding cold-rolled silicon steel sheets, while the middle frame is formed by winding amorphous alloy strips to further improve the design magnetic flux density of the three-dimensional wound core.

[0050] Furthermore, in one embodiment of this invention, a magnetic adhesive is coated between the cold-rolled silicon steel sheet and the amorphous alloy strip; that is, the contact surface 13 between the inner frame 11 and the outer frame 12 is coated with magnetic adhesive. The magnetic permeability of the magnetic adhesive is much higher than that of air and transformer oil. The magnetic adhesive can fill the microscopic gap between the two strips, providing a continuous low-resistance path for the magnetic field lines, thereby reducing the scattering and loss of magnetic flux at the interface between the two strips and improving the overall magnetic circuit efficiency. It should be noted that, in order to ensure that the three-dimensional wound core is grounded at one point, in this embodiment, when one of the core frames 1 is coated with magnetic adhesive, the grounding plate 14 is embedded between the inner frame 11 and the outer frame 12 to avoid overheating of the core circulation due to multiple grounding points.

[0051] In one embodiment of this utility model, the thickness of the inner frame 11 is denoted as d, and the thickness of the core frame 1 is denoted as D; then, d and D satisfy: 0.4 ≤ d / D ≤ 0.6. The advantage of cold-rolled silicon steel sheets lies in their high saturation magnetic induction intensity, meaning they are less prone to magnetic saturation under strong magnetic fields and can handle greater power. The outstanding advantage of amorphous alloy strips is their low iron loss; their no-load loss can be 60%–80% lower than that of silicon steel. Therefore, under different magnetic flux density conditions, it is necessary to reasonably adjust the winding thickness of the cold-rolled silicon steel sheets so that both the cold-rolled silicon steel sheets and amorphous alloy strips can fully utilize their respective advantages. In this embodiment, the thickness of the cold-rolled silicon steel sheets is 0.18–0.27 mm, and the thickness of the amorphous alloy strips is 0.02–0.025 mm. By controlling the ratio of the thickness of the inner frame 11 to the thickness of the core frame 1 between 0.4 and 0.6, the design magnetic flux density of the three-dimensional wound core can reach 1.7T, while simultaneously reducing the no-load loss of the transformer by approximately 20%.

[0052] In this embodiment, after the inner frame 11 is rolled, the outer frame 12 needs to be rolled on top of the inner frame 11. At this time, the amorphous alloy strip needs to be overlapped with the surface of the cold-rolled silicon steel sheet, and the overlap between the two should not be less than 20mm to reduce magnetic flux distortion. In addition, to avoid affecting the flatness of the amorphous alloy strip during rolling, the flatness of the overlap between the amorphous alloy strip and the cold-rolled silicon steel sheet should not exceed 0.02mm. It should also be noted that during the annealing of the three-dimensional rolled core, a distributed annealing composite process is adopted. First, the high-temperature crystallization annealing of the inner frame is completed, and the cold-rolled silicon steel sheet is held at 780℃. Then, the low-temperature stress-relief annealing of the outer frame is performed, and the amorphous alloy strip is held at 400℃ to simultaneously achieve stress release of the two strips.

[0053] In one embodiment of this utility model, please refer to Figure 4 and Figure 5The winding 2 includes an A-phase winding 21, a B-phase winding 22, and a C-phase winding 23. The leads of the A-phase winding 21, B-phase winding 22, and C-phase winding 23 are spaced apart along the height direction of the core column. The core structure also includes a busbar group 4, which includes parallel A-phase lead copper busbars 41, B-phase lead copper busbars 42, C-phase lead copper busbars 43, and a zero-phase lead copper busbar. The A-phase lead copper busbar 41 is parallel to the radial plane of the A-phase winding 21. The leads of the A-phase winding 21, B-phase winding 22, and C-phase winding 23 are respectively connected to the A-phase lead copper busbars 41, B-phase lead copper busbars 42, and C-phase lead copper busbars 43. The neutral points of the A-phase winding 21, B-phase winding 22, and C-phase winding 23 are all connected to the zero-phase lead copper busbar. The leads of the three-phase windings A, B, and C are spaced apart along the height of the core column, ensuring a certain insulation distance between the copper busbars of phases A, B, and C in the vertical direction. This effectively prevents phase-to-phase discharge and arcing, improving the long-term operational reliability of the transformer under high voltage or harsh environments. Similarly, the zero-phase copper busbar is led out from the neutral point of the three-phase windings A, B, and C, and maintains a certain insulation distance from the copper busbars of phases A, B, and C to prevent discharge and arcing between the zero-phase and the copper busbars of phases A, B, and C.

[0054] It should also be noted that in this embodiment, the lead copper busbars of phases A, B, and C, as well as the zero phase, are all arranged radially parallel to the A-phase winding 21. That is, each phase copper busbar is horizontally arranged, which allows the wide surface of each phase copper busbar to be parallel to the direction of the nearby strong leakage magnetic field. This reduces the effective area of ​​the magnetic field penetrating the copper busbar, thus helping to reduce eddy current losses in each phase copper busbar. Furthermore, the lead copper busbars of phases A, B, and C, as well as the zero phase, are all parallel to each other, enabling the copper busbars connected to each phase winding to generate two magnetic fields in opposite directions. This reduces the magnetic flux leaking to the outside, thereby reducing eddy current losses.

[0055] This utility model also proposes a transformer, which includes an iron core structure. The specific structure of the iron core structure is as described in the above embodiments. Since this transformer adopts all the technical solutions of all the above embodiments, it has at least all the beneficial effects brought about by the technical solutions of the above embodiments, which will not be repeated here. Please refer to [link to relevant documentation]. Figure 5The transformer also includes a housing 5 and a leakage flux compensator 6. The core structure is installed in a cavity formed inside the housing 5. The leakage flux compensator 6 includes a sensor 61, a connector 62, and a smart terminal 63. The sensor 61 is communicatively connected to the smart terminal 63, and the connector 62 is electrically connected to the smart terminal 63. The sensor 61 is a Hall sensor, which is installed on the inner wall of the housing 5 and positioned vertically between the A-phase lead copper busbar 41 and the C-phase lead copper busbar 43. The connector 62 is clamped to at least one of the three-phase lead copper busbars. The smart terminal 63 is installed on the outer wall of the housing 5. The sensor 61 transmits the monitoring signal to the smart terminal 63. The control module of the smart terminal 63 determines the leakage flux compensation parameters and controls the connector 62 in real time to automatically generate a magnetic flux opposite to the direction of leakage flux to cancel or significantly reduce leakage flux. It should be noted that there are various types of magnetic flux leakage compensators 6. This embodiment only provides an installation example and operation process for one type of magnetic flux leakage compensator 6. Those skilled in the art can also select other types of magnetic flux leakage compensators 6 according to design requirements.

[0056] The above description is merely an exemplary embodiment of the present utility model and does not limit the scope of protection of the present utility model. Any equivalent structural transformations made based on the technical concept of the present utility model and the contents of the present utility model specification and drawings, or direct / indirect applications in other related technical fields, are included within the scope of protection of the present utility model.

Claims

1. A core structure, characterized in that, include: Three-dimensional coiled iron core, including core post and yoke; The winding is wound around the core post; The fixing clamp includes an upper clamp, a lower clamp, and a pull member. The upper clamp and the lower clamp each include a frame and a pad. The frame includes multiple non-magnetic steel plates, which are joined end to end to form the frame. The frame is sleeved on the end of the three-dimensional coiled iron core. The yoke and part of the core column are in contact with the inner wall of the frame. The pad is connected to the frame and is used to support the winding and the yoke. The pull member is used to pull the upper clamp and the lower clamp together.

2. The core structure as described in claim 1, characterized in that, The inner wall of the frame forms a receiving space for accommodating the iron yoke and part of the core column. The non-magnetic steel plate has an oil guide hole, which is connected to the receiving space.

3. The core structure as described in claim 2, characterized in that, The upper clamp and the lower clamp also include a magnetic guide plate, which is installed in the oil guide hole.

4. The core structure as described in claim 1, characterized in that, The pad includes a base plate, a column, and a pressure plate. The base plate is installed on the frame. The two ends of the column are connected to the base plate and the pressure plate, respectively. The top end of the winding abuts against the pressure plate in the upper clamp, and the bottom end of the winding abuts against the pressure plate in the lower clamp.

5. The core structure as described in claim 4, characterized in that, The base plate includes three support plates arranged at a 120-degree angle. The support plates are connected to the frame and abut against the yoke. The column is installed at the intersection of the three support plates.

6. The core structure as described in any one of claims 1 to 5, characterized in that, The three-dimensional coiled iron core includes three iron core frames, and the three-dimensional coiled iron core is formed by assembling the three iron core frames to form a triangular three-dimensional structure. The three-dimensional coiled iron core includes three core columns distributed in a triangular pattern. The iron core frame includes an inner frame and an outer frame. The inner frame is made of cold-rolled silicon steel sheet, and the outer frame is made of amorphous alloy strip.

7. The core structure as described in claim 6, characterized in that, A magnetic adhesive is coated between the cold-rolled silicon steel sheet and the amorphous alloy strip.

8. The core structure as described in claim 6, characterized in that: the thickness of the inner frame is d, and the thickness of the core frame is D; Therefore, d and D satisfy: 0.4≤d / D≤0.

6.

9. The core structure as described in claim 6, characterized in that, The winding includes an A-phase winding, a B-phase winding, and a C-phase winding. The leads of the A-phase winding, the B-phase winding, and the C-phase winding are spaced apart along the height direction of the core column. The core structure also includes a busbar group, which includes parallel A-phase lead copper busbars, B-phase lead copper busbars, C-phase lead copper busbars, and a zero-phase lead copper busbar. The A-phase lead copper busbars are parallel to the radial plane of the A-phase winding. The leads of the A-phase winding, the B-phase winding, and the C-phase winding are respectively connected to the A-phase lead copper busbar, the B-phase lead copper busbar, and the C-phase lead copper busbar. The neutral point of the A-phase winding, the B-phase winding, and the C-phase winding is connected to the zero-phase lead copper busbar.

10. A transformer, characterized in that, Includes the core structure as described in any one of claims 1 to 9.

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