Anti-cracking epoxy pouring coil structure of dry-type transformer

Abstract

The utility model discloses an anti-cracking epoxy pouring coil structure of a dry-type transformer, which can improve the internal stress distribution of resin and a conductor and enhance the mechanical strength of a pouring coil. Specifically, a framework formed by the glass fiber grids inside and outside the coil can effectively prevent resin on the surface of the transformer coil from cracking during production and operation of the cast coil, the grids are filled with the air channel ribs, and the glass fiber tubes outside the air channel are filled with the air channel ribs, so that the stress effect generated by expansion caused by heat and contraction caused by cold during operation of the coil can be borne; the air passage ribs are prevented from cracking; the coefficient of expansion caused by heat and contraction caused by cold of the resin filled with the glass fiber grid is closer to that of the conductor, so that gaps between the resin and the conductor during operation are avoided. The resin casting coil adopting the structure can reliably operate in a normal-temperature region, can be stored for a long time in a low-temperature region, and can rapidly operate in a full load without cracking at a lower temperature.

Description

TECHNICAL FIELD

[0001] The utility model relates to the design and production technical field of epoxy resin cast coil of dry type transformer, especially relates to a dry type transformer anti-cracking epoxy cast coil structure. BACKGROUND

[0002] With the continuous improvement of city power grid power supply requirement and the progress of transformer technology, the epoxy cast dry type transformer has been very popular in our country, and the epoxy cast dry type transformer is widely applied in various trades and professions because of the advantages of energy saving, safety, reliability and good flame retardant performance.

[0003] Because the transformer coil exists internal stress in the process of pouring solidification and the coil will heat and expand due to the existing resistance in the process of operation, under the condition that the thermal expansion and cold shrinkage coefficients of the conductor and the resin are not the same, the surface of the coil and the surface of the internal air passage resin will often crack, the moisture-proof and dust-proof ability of the coil will be reduced after the resin cracks, the insulation ability of the coil will be reduced after the crack reaches the conductor part of the coil, partial discharge and other problems will occur, and the coil layer or turn-to-turn insulation will be broken down after a long time, so that the transformer coil is invalid, the transformer is out of operation, and direct or indirect economic losses will be caused to the power consumption unit. UTILITY MODEL CONTENTS

[0004] The utility model discloses a dry type transformer anti-cracking epoxy cast coil structure, reduces the difference of the thermal expansion and cold shrinkage coefficient of epoxy resin and conductor material, improves the mechanical strength of the coil surface and air passage after the epoxy resin solidification, enhances the stress tearing ability generated by thermal expansion and cold shrinkage, avoids the risk of cracking of the transformer coil in operation, and guarantees the reliable operation of the transformer.

[0005] To solve the above technical problems, the utility model provides a dry type transformer anti-cracking epoxy cast coil structure, which comprises an inner glass fiber grid skeleton and an outer glass fiber grid skeleton arranged in a sleeving mode, and the conductor of the coil is wound on the inner glass fiber grid skeleton and the outer glass fiber grid skeleton according to the designed coil segment number and layer number.

[0006] A gas passage outer glass fiber tube is sleeved on the gas passage plate preburied in the coil structure to form a gas passage.

[0007] The boss part of the welding terminal of the coil structure is filled with glass fiber grid to form a glass fiber coil boss, and the conductor of the terminal and the outer part of the terminal are loosely wrapped with glass silk cloth.

[0008] The wound coil is additionally provided with an outer mold and a wiring cover plate, then resin is poured, and the coil product is formed after high-temperature solidification.

[0009] Preferably, the inner glass fiber mesh skeleton and the outer glass fiber mesh skeleton are both formed by wrapping a plurality of layers of glass fiber mesh on a mold to form a coil skeleton with a certain thickness.

[0010] Preferably, the coil structure is filled with glass fiber mesh between the coils.

[0011] Preferably, the plurality of coil air channels are uniformly distributed around the central axis within the coil, and each coil air channel is formed by embedding an air channel plate in the coil.

[0012] Preferably, the gap between the two adjacent coil air channels is filled with an air channel rib filling mesh.

[0013] Preferably, after the winding of the coil structure is completed, a plurality of layers of glass fiber mesh are wrapped outside to form a protective layer.

[0014] Compared with the prior art, the dry-type transformer anti-cracking epoxy pouring coil structure has the following beneficial effects:

[0015] After the dry-type transformer anti-cracking epoxy pouring coil structure is adopted, the internal stress distribution of the resin and the conductor can be improved, and the mechanical strength of the pouring coil can be enhanced. Specifically, the skeleton formed by the inner and outer glass fiber meshes of the coil can effectively prevent the resin on the surface of the transformer coil from cracking during production and operation. The air channel rib filled with the air channel rib filling mesh and the air channel outer glass fiber tube can withstand the stress generated by thermal expansion and cold contraction during coil operation, thereby preventing the air channel rib from cracking. The coefficient of thermal expansion and cold contraction of the resin filled with the glass fiber mesh and the conductor is more close, thereby avoiding the gap between the resin and the conductor during operation. The resin pouring coil with this structure not only can be reliably operated in normal temperature areas, but also can be stored for a long time in low temperature areas, and can be quickly and fully operated without cracking at a relatively low temperature. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 is a schematic view of the dry-type transformer anti-cracking epoxy pouring coil structure provided by the present application;

[0017] Figure 2 is Figure 1 is a sectional view of A-A in FIG. 1;

[0018] Figure 3 is Figure 1 is a sectional view of B-B in FIG. 1.

[0019] In the figure: 1, inner glass fiber mesh skeleton; 2, outer glass fiber mesh skeleton; 3, coil air channel; 4, air channel outer glass fiber tube; 5, air channel rib filling mesh; 6, glass fiber coil boss; 7, resin. DETAILED DESCRIPTION

[0020] The following is a further detailed description of the present invention in conjunction with the accompanying drawings and specific embodiments. The advantages and features of the present invention will become more apparent from the following description and claims. It should be noted that the drawings are greatly simplified and not to exact scale, and are intended solely to facilitate and clearly illustrate the embodiments of the present invention.

[0021] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0022] In the description of this utility model, it should be noted that, unless otherwise expressly specified or limited, the terms "installed," "connected," and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; mechanical connections, electrical connections; direct connections, indirect connections through an intermediate medium, and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in this utility model based on specific circumstances. Example

[0023] The utility model provides a dry-type transformer anti-cracking epoxy casting coil structure, please refer to Figures 1-3 , including an inner glass fiber mesh frame 1 and an outer glass fiber mesh frame 2 that are arranged in a sheathed manner, and the coil wires are wound on the inner glass fiber mesh frame 1 and the outer glass fiber mesh frame 2 according to the designed number of coil segments and layers; and an outer glass fiber tube 4 is sheathed on the airway plate pre-buried to form the coil airway 3 inside the coil structure.

[0024] The boss portion of the welding terminal of the coil structure is filled with a glass fiber mesh to form a glass fiber coil boss 6; and the wires of the terminal and the outside of the terminal are loosely wrapped with glass fiber cloth tape; the wound coil is installed with an outer mold and a wiring cover, and then resin 7 is poured, and after high-temperature curing, the finished coil is formed.

[0025] Specifically, the inner glass fiber grid skeleton 1 and the outer glass fiber grid skeleton 2 are both formed by wrapping multiple layers of glass fiber grids on a mold to form a coil skeleton with a certain thickness.

[0026] Specifically, the inter-coil gaps of the coil structure are filled with inter-segment glass fiber meshes.

[0027] Specifically, the plurality of coil air channels 3 are uniformly distributed around the central axis in the coil, and an independent air channel outer glass tube 4 is sleeved on each air channel plate on which the coil air channel 3 is embedded; and the gap between the adjacent two coil air channels 3 is filled with an air channel rib filling grid 5.

[0028] Specifically, after the winding of the coil structure is completed, the outer part is wrapped with a plurality of layers of glass fiber grids to form a protective layer.

[0029] After the dry-type transformer anti-cracking epoxy pouring coil structure of the utility model is used, the internal stress distribution of the resin 7 and the conductor can be improved, and the mechanical strength of the pouring coil is enhanced. Specifically, the skeleton formed by the glass fiber grids inside and outside the coil can effectively prevent the resin on the surface of the transformer coil from cracking during production and operation of the pouring coil. The air channel rib filled with the air channel rib filling grid 5 and the air channel outer glass tube 4 can withstand the stress generated by thermal expansion and cold contraction during the operation of the coil, and prevent the cracking of the air channel rib. The coefficient of thermal expansion and cold contraction of the resin 7 and the conductor filled with the glass fiber grid is more close, and the gap between the resin 7 and the conductor during operation is avoided. The resin pouring coil with this structure can not only be reliably operated in normal temperature areas, but also can be stored for a long time in low temperature areas, and can be quickly and fully operated at a low temperature without cracking.

[0030] The above description is only a description of the preferred embodiment of the utility model, and does not limit the scope of the utility model. Any modification made by the ordinary skilled in the art according to the above disclosure is within the protection scope of the claims.

Claims

1. A dry-type transformer anti-cracking epoxy cast coil structure, characterized in that, The inner glass fiber mesh skeleton (1) and the outer glass fiber mesh skeleton (2) are sleeved, the wires of the coil are wound on the inner glass fiber mesh skeleton (1) and the outer glass fiber mesh skeleton (2) according to the designed coil segment number and layer number; The air channel outer fiberglass pipe (4) is sleeved on the air channel plate pre-embedded to form the coil air channel (3) inside the coil structure; The boss part of the welding terminal of the coil structure is filled with glass fiber mesh to form the fiberglass coil boss (6); and the wire of the terminal and the outside of the terminal are loosely wrapped with glass silk cloth tape; After the wound coil is added with an outer mold and a wiring cover plate, resin (7) is poured, and after high-temperature curing, the coil product is formed.

2. A dry-type transformer anti-cracking epoxy cast coil structure according to claim 1, characterized in that, The inner glass fiber mesh skeleton (1) and the outer glass fiber mesh skeleton (2) are both formed into a coil skeleton with a certain thickness by wrapping multiple layers of glass fiber mesh on a mold.

3. A dry-type transformer anti-cracking epoxy cast coil structure according to claim 1, characterized in that, The inter-coil gap filling section of the coil structure is filled with glass fiber mesh.

4. The anti-cracking epoxy casting coil structure of a dry-type transformer according to claim 1, characterized in that: Multiple coil air channels (3) are uniformly distributed around the central axis in the coil, and an independent air channel outer fiberglass pipe (4) is sleeved on each air channel plate pre-embedded to form a coil air channel (3).

5. A dry-type transformer anti-cracking epoxy cast coil structure according to claim 4, characterized in that, The gap between the adjacent two coil air channels (3) is filled with air channel rib filling mesh (5).

6. A dry-type transformer anti-cracking epoxy cast coil structure according to claim 1, characterized in that, After the winding of the wire of the coil structure is completed, multiple layers of glass fiber mesh are wrapped outside to form a protective layer.

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