Transformer body and transformer

Abstract

According to the transformer body and the transformer, a neutral point lead is wound around an iron core window from the outer portion of the iron core window, so that the phenomena of zero-sequence current, no-load increase and the like caused by the fact that the neutral point lead penetrates through the iron core window can be avoided, noise and vibration of an iron core are reduced, and eddy-current loss generated on a metal piece is avoided. The transformer body comprises an iron core, a winding unit (4) and a neutral point lead (5). The winding unit (4) is wound on an iron core main column (1) of the iron core; in the winding unit (4), a head end outgoing line and a tail end outgoing line of a star connection winding connected in a star connection mode are both located on the same side of the iron core, the head end outgoing line of the star connection winding is connected to a voltage regulation lead sleeve, and the tail end outgoing line of the star connection winding is connected to a neutral point lead (5). And the neutral point lead (5) is connected with the tail end of the star-connected winding, then bypasses the iron core window from the outer part of the iron core window of the iron core, and is connected to the neutral point sleeve.

Description

Technical Field

[0001] The utility model belongs to the technical field of transformer manufacturing, and particularly relates to a transformer body and a transformer. Background Art

[0002] Power transformers are the core equipment for energy transmission in power grids. Their safe, reliable, and economical operation has a crucial impact on the entire grid. In the transformer manufacturing industry, some transformers employ a method where the first and last leads of the windings are arranged on opposite sides of the core. This has the advantage of facilitating the placement of the first and last bushings on opposite sides, saving overall transformer layout space. However, this also results in the coils having an extra half turn of lead wire passing through the core window.

[0003] The magnetic flux in the side yokes of the window-through lead wire leads to a zero-sequence component in the induced voltage on the high-voltage side. When the transformer is operating under load, the zero-sequence loop is activated, generating a large neutral-point current. This neutral-point current injects zero-sequence current into the ground grid, reducing the sensitivity of the zero-sequence protection and exacerbating the imbalance in the magnetic flux distribution between the left and right side yokes of the transformer core. Furthermore, this neutral-point current generates additional magnetic flux within the core, increasing the core's no-load losses, degrading the core's temperature rise characteristics, and exacerbating core noise and vibration. The half-turn lead wire also passes through other metal components on the core, generating eddy current losses in these components. Utility Model Content

[0004] The technical problem to be solved by the present invention is to address the above-mentioned deficiencies in the prior art and to provide a transformer body and a transformer. By allowing the neutral point lead to bypass the core window from the outside, the zero-sequence current and no-load increase caused by the neutral point lead passing through the core window can be avoided, thereby reducing core noise and vibration, and avoiding eddy current losses on metal parts.

[0005] In a first aspect, an embodiment of the present invention provides a transformer body, comprising an iron core, a winding unit, and a neutral point lead. The winding unit is wound on a core main column of the iron core; in the winding unit, the head-end and tail-end leads of a star-connected winding connected in a star-connected manner are both located on the same side of the iron core, the head-end lead of the star-connected winding is connected to a voltage regulating lead bushing, and the tail-end lead of the star-connected winding is connected to a neutral point lead. After the neutral point lead is connected to the tail end of the star-connected winding, it passes through the core window of the iron core from the outside and is connected to the neutral point bushing.

[0006] In some embodiments, the core structure is a three-phase five-leg core structure. The number of winding units is three, and the three winding units are respectively wound on the three main legs in the center of the core; the tail ends of the star-connected windings in the three winding units are all connected to the neutral point lead.

[0007] In some embodiments, the winding unit includes a high-voltage winding and a low-voltage winding, wherein the high-voltage winding and the low-voltage winding are coaxially wound on corresponding core main legs of the core in sequence. The high-voltage winding is connected in a star-connected manner to form the star-connected winding.

[0008] In some embodiments, the winding unit further includes a voltage regulating winding, and the high-voltage winding, the voltage regulating winding, and the low-voltage winding are coaxially wound in sequence on corresponding core main columns of the core.

[0009] In some embodiments, the core is formed by stacking multiple layers of cold-rolled grain-oriented silicon steel sheets.

[0010] In some embodiments, the core further includes a core clamp, which is disposed on both sides of the multi-layer cold-rolled grain-oriented silicon steel sheet and is used to clamp the multi-layer cold-rolled grain-oriented silicon steel sheet.

[0011] In some embodiments, the neutral point lead is coated with an insulating structure on the outside.

[0012] Thus, the transformer body in the embodiment of the present invention facilitates the arrangement of the voltage regulating lead and the neutral bushing on opposite sides of the core by arranging the head and tail outgoing wires of the star-connected winding connected in a star-connected manner in the winding unit on the same side of the core, and connecting the tail outgoing wire of the star-connected winding to the neutral point lead. After the neutral point lead is connected to the tail end of the star-connected winding, it bypasses the core window from outside the core window and connects to the neutral point bushing. This saves space for the overall layout of the transformer. Furthermore, in this case, when the transformer winding is operating, the bypass yoke magnetic flux is unlikely to affect the neutral point lead, thus avoiding the generation of a large neutral point current in the neutral point lead, thereby preventing the neutral point current from injecting zero-sequence current into the ground grid and reducing the sensitivity of the zero-sequence protection, and preventing the neutral point current from causing additional magnetic flux in the core, thereby reducing the no-load loss of the core, optimizing the temperature rise characteristics of the core, reducing core noise and vibration, and improving the reliability of the transformer, thereby improving the safety and reliability of the power grid. Compared with the prior art, the eddy current loss caused by the half-turn lead passing through other metal parts on the iron core in the prior art is avoided.

[0013] In a second aspect, an embodiment of the present invention further provides a transformer, comprising an oil tank and the transformer body of the first aspect. The oil tank is filled with insulating oil. The transformer body is located within the oil tank and immersed in the insulating oil.

[0014] In some embodiments, a neutral point bushing is provided on the oil tank, the neutral point bushing being located on a side of the core opposite to the tail end of the star-connected winding. A neutral point lead of the transformer body passes through the neutral point bushing and is connected to an external neutral point terminal.

[0015] In some embodiments, the transformer further includes an oil pillow, which is disposed on top of the oil tank and communicates with the interior of the oil tank for adjusting the volume change of the insulating oil in the oil tank.

[0016] The transformer provided by the embodiment of the present invention has the same beneficial effects as the above-mentioned transformer body, which will not be described in detail here. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 : A schematic diagram of a transformer body provided in an embodiment of the present utility model. DETAILED DESCRIPTION

[0018] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention is further described in detail below with reference to the accompanying drawings and embodiments.

[0019] Example 1:

[0020] like Figure 1 As shown, an embodiment of the present invention provides a transformer body, which is used in a transformer.

[0021] like Figure 1 As shown, the transformer body includes an iron core, a winding unit 4, and a neutral point lead 5. The winding unit 4 is wound around the core main leg 1. Within the winding unit 4, the star-connected winding's head-end lead A and tail-end lead X' are both located on the same side of the iron core. The star-connected winding's head-end lead A is connected to the voltage regulator lead, while the tail-end lead X' is connected to the neutral point lead 5. After connecting to the tail end of the star-connected winding, the neutral point lead 5 passes outside the core window and around it, connecting to the neutral point bushing.

[0022] The iron core is the magnetic circuit part in the transformer body, used to provide a path for the magnetic flux of the winding unit 4.

[0023] like Figure 1 As shown, the core includes a plurality of core legs, and the plurality of core legs include a core main leg 1 and core side legs 2 . The core side legs 2 are located on both sides of the core main leg 1 .

[0024] The space between two adjacent core columns forms a core window. Figure 1 In the embodiment, the space between the core main column 1 and the core side column 2 and the space between the two core main columns 1 form core windows.

[0025] Figure 1 The top view of the transformer body, the first end outgoing line A and the tail end outgoing line X' of the star-connected winding are both located at Figure 1 On the lower side of the core, the end of the neutral point lead 5 that is not connected to the tail end outgoing line X' of the star-connected winding is located Figure 1Therefore, the neutral point lead 5 passes around the core window from the outside and is located on the other side of the core, that is, on a different side from the head end of the star winding, which facilitates the arrangement of the voltage regulating lead and the neutral point bushing on different sides, saving the overall layout space of the transformer.

[0026] During transformer winding operation, the bypass yoke magnetic flux is less likely to affect the neutral-point lead 5, preventing a large neutral-point current from being generated in the neutral-point lead 5. This prevents the neutral-point current from injecting zero-sequence current into the ground grid and reducing the sensitivity of the zero-sequence protection. It also prevents the neutral-point current from generating additional magnetic flux within the core, thereby reducing the core's no-load losses, optimizing the core's temperature rise characteristics, and minimizing core noise and vibration. Compared to existing technologies, this eliminates the eddy current losses generated by the half-turn lead passing through other metal parts on the core.

[0027] Thus, the transformer body of the embodiment of the present invention facilitates the placement of the voltage regulating lead and neutral bushing on opposite sides of the core by locating the head-end lead A and tail-end lead X' of the star-connected winding in the winding unit 4, which is connected in a star-connected manner, on the same side of the core. Furthermore, the tail-end lead X' of the star-connected winding is connected to the neutral point lead 5. After the neutral point lead 5 is connected to the tail end of the star-connected winding, it then bypasses the core window from outside the core and connects to the neutral point bushing. This saves space for the overall transformer layout. Furthermore, when the transformer winding is operating, the bypass yoke magnetic flux is less likely to affect the neutral point lead 5, thus preventing the generation of a large neutral point current in the neutral point lead 5. This prevents the neutral point current from injecting zero-sequence current into the ground grid and reducing the sensitivity of the zero-sequence protection. It also prevents the neutral point current from generating additional magnetic flux within the core, thereby reducing the core's no-load loss, optimizing the core's temperature rise characteristics, reducing core noise and vibration, and improving the transformer's operational reliability, thereby improving the safety and reliability of the power grid. Compared with the prior art, the eddy current loss caused by the half-turn lead passing through other metal parts on the iron core in the prior art is avoided.

[0028] In some embodiments, as Figure 1 As shown, the core structure is a three-phase five-leg structure. There are three winding units 4, each wound around the three main legs 1 in the center of the core. The tail leads X' of the star-connected windings in the three winding units 4 are all connected to the neutral point lead 5.

[0029] like Figure 1 As shown, the core includes five core legs, which are three core main legs 1 and two core side legs 2 . The two core side legs 2 are located on both sides of the three core main legs 1 .

[0030] Exemplarily, the three winding units 4 correspond to three phases of the three-phase electricity respectively.

[0031] The above configuration provides a more defined path for the side yoke magnetic flux. The side yoke can better share the pressure of the magnetic circuit, especially in situations such as overexcitation or asymmetric loads. The independent side yoke can effectively alleviate the problem of magnetic flux saturation in the core, improving the transformer's overload resistance and stability.

[0032] In some embodiments, the winding unit 4 includes a high-voltage winding and a low-voltage winding, which are coaxially wound on the corresponding core main column 1 of the core in sequence; the high-voltage winding is connected in a star-connected manner to form the above-mentioned star-connected winding.

[0033] The high-voltage winding connected in star connection can provide a current path at the neutral point when the three-phase load of the high-voltage winding is unbalanced, so that the three-phase voltage can remain relatively stable.

[0034] Through the above arrangement, the electric energy in the high-voltage winding and the electric energy in the low-voltage winding can be transferred to each other, realizing the voltage transformation function of the transformer body and maintaining the relative stability of the three-phase voltage in the high-voltage winding.

[0035] In some embodiments, the winding unit 4 further includes a voltage regulating winding, and the high-voltage winding, the voltage regulating winding, and the low-voltage winding are coaxially wound on the corresponding core main column 1 of the core in sequence.

[0036] Through the above arrangement, the electric energy in the high-voltage winding, the electric energy in the low-voltage winding and the electric energy in the voltage regulating winding can be transferred to each other, thereby realizing the voltage regulating function of the transformer body.

[0037] In some embodiments, the core is formed by laminating multiple layers of cold-rolled grain-oriented silicon steel sheets.

[0038] The magnetism of cold-rolled grain-oriented silicon steel sheets has strong directionality and high magnetic permeability, which can reduce the iron loss value of the transformer body during operation and reduce the temperature rise of the transformer body.

[0039] In some embodiments, as Figure 1 As shown, the core further includes a core clamp 3, which is arranged on both sides of the multi-layer cold-rolled grain-oriented silicon steel sheet and is used to clamp the multi-layer cold-rolled grain-oriented silicon steel sheet.

[0040] The core clamp 3 can fix multiple layers of cold-rolled grain-oriented silicon steel sheets and reduce the gaps between the multiple layers of cold-rolled grain-oriented silicon steel sheets, thereby improving the magnetic circuit performance on the core, reducing the iron loss value of the transformer body during operation, and reducing the temperature rise of the transformer body.

[0041] In some embodiments, the outside of the neutral point lead 5 is covered with an insulating structure.

[0042] The insulation structure can be insulating paper, and the thickness of the insulating paper can be adjusted according to actual needs.

[0043] The insulating structure can provide insulation for the neutral point lead 5, thereby ensuring the electrical safety of the transformer body.

[0044] In summary, the transformer body of the present invention has the advantages of stable structure, good vibration resistance and high reliability.

[0045] Example 2:

[0046] The present invention also provides a transformer for use in a power supply network. The transformer includes an oil tank and the transformer body of Example 1. The oil tank is filled with insulating oil. The transformer body is located within the oil tank and immersed in the insulating oil.

[0047] The insulating oil can be mineral oil, natural fatty oil or synthetic fatty oil.

[0048] Insulating oil can provide insulation and heat dissipation for the transformer body.

[0049] The transformer body is fixed inside the oil tank.

[0050] The transformer body in this embodiment can avoid the increase of zero-sequence current and no-load caused by the neutral point lead 5 passing through the core window, thereby reducing the loss and vibration of the transformer, improving the operational reliability of the transformer, and thus ensuring the safety of the power supply network.

[0051] In some embodiments, a neutral point bushing is provided on the oil tank and is located on the side of the core opposite to the tail end of the star-connected winding. A neutral point lead 5 of the transformer body passes through the neutral point bushing and is connected to an external neutral point terminal.

[0052] The neutral point bushing is used to achieve insulation between the neutral point lead 5 and the shell of the oil tank.

[0053] There are many types of neutral point bushings. Different types of neutral point bushings can be selected according to the voltage level of the transformer. For example, when the voltage range of a general transformer is 10-35kV, an air-filled or oil-filled bushing can be used. When the voltage range of the transformer is above 110kV, a capacitor bushing can be used. When the transformer is low voltage, a solid porcelain bushing can be used. The specific type can be adjusted according to actual needs.

[0054] Through the above settings, the safety level of the transformer can be improved.

[0055] In some embodiments, the transformer further includes an oil pillow, which is disposed on top of the oil tank and communicates with the interior of the oil tank for adjusting the volume change of the insulating oil in the oil tank.

[0056] When the transformer temperature rises, the volume of the insulating oil expands and the oil pillow can store excess oil; when the transformer temperature drops, the volume of the insulating oil shrinks and the oil in the oil pillow can be added to the oil tank, keeping the oil tank always full of insulating oil to ensure the normal operation of the transformer.

[0057] It is understood that the above embodiments are merely exemplary embodiments for illustrating the principles of the present invention, and the present invention is not limited thereto. Those skilled in the art may make various modifications and improvements without departing from the spirit and substance of the present invention, and such modifications and improvements are also considered to be within the scope of protection of the present invention.

Claims

1. A transformer body, characterized in that: include: core; A winding unit (4) is wound on the core main column (1) of the core; in the winding unit (4), the head end outgoing wire and the tail end outgoing wire of the star-connected winding connected in a star-connected manner are both located on the same side of the core, the head end outgoing wire of the star-connected winding is connected to the voltage regulating lead bushing, and the tail end outgoing wire of the star-connected winding is connected to the neutral point lead (5); and, A neutral point lead (5) is connected to the tail end of the star-connected winding, then passes around the core window from the outside of the core window, and is connected to the neutral point bushing.

2. The transformer body according to claim 1, characterized in that: The structure of the core is a three-phase five-leg core structure; The number of the winding units (4) is three, and the three winding units (4) are respectively wound on the three core main columns (1) in the middle of the core; the tail end outgoing wires of the star-connected windings in the three winding units (4) are all connected to the neutral point lead (5).

3. The transformer body according to claim 2, characterized in that: The winding unit (4) comprises a high-voltage winding and a low-voltage winding, and the high-voltage winding and the low-voltage winding are coaxially wound in sequence on the corresponding core main columns (1) of the core; The high-voltage windings are connected in a star-connected manner to form the star-connected windings.

4. The transformer body according to claim 3, characterized in that: The winding unit (4) further comprises a voltage regulating winding, wherein the high-voltage winding, the voltage regulating winding and the low-voltage winding are coaxially wound in sequence on the corresponding core main columns (1) of the core.

5. The transformer body according to claim 1, characterized in that: The iron core is formed by stacking multiple layers of cold-rolled grain-oriented silicon steel sheets.

6. The transformer body according to claim 5, characterized in that: The iron core further comprises an iron core clamp (3), which is arranged on both sides of the multi-layer cold-rolled grain-oriented silicon steel sheet and is used for clamping the multi-layer cold-rolled grain-oriented silicon steel sheet.

7. The transformer body according to any one of claims 1 to 6, characterized in that: The outer side of the neutral point lead (5) is covered with an insulating structure.

8. A transformer, characterized in that: include: An oil tank filled with insulating oil; and, The transformer body according to any one of claims 1 to 7 is located inside the oil tank and immersed in the insulating oil.

9. The transformer according to claim 8, characterized in that A neutral point bushing is provided on the oil tank, and the neutral point bushing is located on a side of the iron core opposite to the tail end of the star-connected winding; The neutral point lead (5) of the transformer body passes through the neutral point bushing and is connected to an external neutral point terminal.

10. The transformer according to claim 8 or 9, characterized in that: Also includes oil pillow; The oil pillow is arranged on the upper part of the oil tank and is communicated with the interior of the oil tank, and is used to adjust the volume change of the insulating oil in the oil tank.

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