A dry-type split transformer and its installation method

Abstract

The present invention relates to a dry-type split transformer and its installation method. The structure includes at least two layers of windings distributed axially, with a guide structure disposed between the two layers of windings. The guide structure includes a plurality of pads distributed circumferentially and an air duct plate connected between the pads. The pads and the air duct plate form a cylindrical structure. Each pad includes an epoxy resin structural member and silicone rubber. Two bosses are provided on the upper and lower sides of the epoxy resin structural member, respectively. The high-voltage and low-voltage coils in each coil group are disposed on either side of the two bosses. A positioning groove is provided between the two bosses on the same side, and an insulating tube is engaged in the positioning groove. One end of the epoxy resin structural member is provided with a chamfer, and the other end is provided with a longitudinally disposed slot. The two ends of the air duct plate are respectively engaged in the slots of the pads located on both sides. The silicone rubber is attached to the position where the epoxy resin structural member contacts the high-voltage coil or the low-voltage coil. The present invention can accelerate air flow inside and outside the transformer and extend the service life of the product.

Description

Technical Field

[0001] The present invention relates to the technical field of transformers, and in particular to a dry-type split transformer and an installation method thereof. Background Art

[0002] In conventional split transformers, the distance between two or more axially split coils is typically 10mm to 20mm, and the decoupling rate of these coils is typically between 80% and 85%. As user requirements for decoupling rates continue to rise and as insulation distances for the low-voltage copper busbars of multi-split transformers increase, the distance between the axially split coils has increased significantly, typically reaching 220mm to 260mm, and the decoupling rate has been increased to 90%.

[0003] However, due to the increased distance between the axially split coils, the fan air volume at the bottom of the clamp will be lost through the gap between the axially split coils, reducing the fan's cooling effect on the upper coil. Simulation calculations and actual testing show that the hottest point of the entire coil should be 2 / 3 of the way up the upper coil (measured using the lower end face of the upper coil as the reference). The thermal aging life of a transformer depends primarily on the aging life of its insulation material. Dry-type transformers are made of resin. When the temperature of the coil insulation material exceeds its hottest point by 6K, its service life may be reduced by half (the service life of epoxy-cast dry-type transformers is generally 30 years).

[0004] Therefore, how to bring the cold air from the bottom fan into the upper coil of the split transformer is a technical problem that needs to be solved urgently by those skilled in the art. Summary of the Invention

[0005] The present invention provides a dry-type split transformer and an installation method thereof to solve the above technical problems.

[0006] In order to solve the above technical problems, the present invention provides a dry-type split transformer, comprising at least two layers of windings distributed along the axial direction, each layer of windings comprising a plurality of coil groups, each coil group comprising a high-voltage coil and a low-voltage coil, a main air duct being provided between the high-voltage coil and the low-voltage coil, an insulating cylinder being provided in the main air duct, a flow guide structure being provided between the two layers of axially distributed windings, the flow guide structure comprising a plurality of pads distributed along the circumferential direction and a duct plate connected between the pads, the pads and the duct plate forming a cylindrical structure; each of the pads comprising an epoxy resin structural member and silicone rubber, two bosses are respectively provided on the upper and lower sides of the epoxy resin structural part, and the high-voltage coil and the low-voltage coil in each coil group are respectively arranged on both sides of the two bosses; a positioning groove is provided between the two bosses on the same side, and the insulating tube is clamped in the positioning groove; one end of the epoxy resin structural part is provided with a chamfer, and the other end is provided with a longitudinally arranged groove, and the two ends of the air duct plate are respectively clamped in the grooves of the pads located on both sides; the silicone rubber is attached to the position where the epoxy resin structural part contacts the high-voltage coil or the low-voltage coil.

[0007] Preferably, both ends of the air duct plate are plug-in plates that match the card slots.

[0008] Preferably, the depth of the card slot is 6 mm to 8 mm.

[0009] Preferably, the height of the air duct plate is 2 mm to 4 mm smaller than the height of the pad.

[0010] Preferably, the guide structure includes four pads, and the four pads are evenly distributed along the circumferential direction.

[0011] Preferably, the boss is 20 mm ± 0.5 mm higher than the same side surface of the epoxy resin structural component.

[0012] Preferably, the insulating cylinder is 20 mm to 40 mm higher than the coil assembly in the axial direction.

[0013] The present invention also provides an installation method for the dry-type split transformer as described above. Before installing the guide structure, the pads are first placed circumferentially according to the product layout diagram, and then the inner diameter and thickness of the air duct plate are determined according to the position of the slots on the pads. The corresponding air duct plate is selected according to the inner diameter and thickness.

[0014] Preferably, the air duct plate is cut from a cylinder whose inner diameter and thickness match the slot.

[0015] Compared with the prior art, the dry-type split transformer and the installation method thereof provided by the present invention have the following advantages:

[0016] 1. The present invention utilizes spacers and air duct plates to enclose a cylindrical structure, which is used to connect the main air ducts of the upper and lower layers, thereby reducing the air volume loss of the bottom fan, significantly accelerating the air flow inside and outside the transformer, and extending the service life of the product;

[0017] 2. The present invention is easy and flexible to manufacture and install, has no impact on the overall structure of the transformer, and has little impact on the cost;

[0018] 3. The air duct plate is fixed in the pad through the slot. The product will not increase noise when it is running and the overload capacity of the transformer is increased. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a structural diagram of a dry-type split transformer in a specific embodiment of the present invention;

[0020] Figure 2a and Figure 2b They are respectively a front view and a top view of a cushion block in a specific embodiment of the present invention;

[0021] Figure 3a and Figure 3b They are schematic structural diagrams of two silicone rubbers in one embodiment of the present invention;

[0022] Figure 4a and Figure 4b They are respectively a front view and a top view of an air duct plate in a specific embodiment of the present invention;

[0023] Figure 5 This is a schematic diagram of determining the inner diameter and thickness of the air duct plate according to the position of the slot on the spacer block in the installation method of the dry-type split transformer according to one embodiment of the present invention;

[0024] Figure 6 This is a schematic diagram of the connection between the air duct plate and the spacer in the installation method of the dry-type split transformer in one specific embodiment of the present invention.

[0025] In the figure: 101-upper pad, 102-lower pad, 111, 121, 131-high-voltage coil, 112, 122, 132-low-voltage coil, 113, 123, 133-insulating cylinder, 114, 124, 134-core support bar, 200-guide structure, 210-pad, 211-epoxy resin structural member, 212a, 212b-silicone rubber, 213-boss, 214-positioning groove, 215-chamfer, 216-slot, 220-duct plate, 221-plug plate. DETAILED DESCRIPTION

[0026] In order to describe the technical solution of the above invention in more detail, specific embodiments are listed below to demonstrate the technical effects; it should be emphasized that these embodiments are used to illustrate the present invention but are not intended to limit the scope of the present invention.

[0027] The dry-type split transformer provided by the present invention is as follows Figures 1 to 6 As shown, it includes at least two layers of windings distributed along the axial direction, each layer of windings includes several coil groups, each coil group includes high-voltage coils 111, 121, 131 and low-voltage coils 112, 122, 132, and a main air duct (not shown) is provided between the high-voltage coils 111, 121, 131 and the low-voltage coils 112, 122, 132. Insulating cylinders 113, 123, 133 are provided in the main air duct, and the iron core (not shown) and the low-voltage coils 112, 122, 132 are connected by iron core struts 114, 124, 134. In this embodiment, a high-decoupling-rate three-split transformer is used as an example. There are three layers of windings, named from top to bottom as the first layer, the second layer, and the third layer. Each layer contains four coil groups. Taking the first layer as an example, each coil group includes a high-voltage coil 111 and a low-voltage coil 112. An insulating cylinder 113 is provided in the main air duct. The insulating cylinder 113 can be used to enhance the main insulation between the high and low voltages and facilitate heat exchange between the transformer air duct and the outside world. Iron core braces 114 are used to securely fasten the low-voltage coil 112 to the iron core. The remaining coil groups in the first layer, as well as the coil groups in the second and third layers, are identical to the above-described structures and will not be described in detail here.

[0028] A guide structure 200 is provided between the two axially distributed winding layers. The guide structure 200 includes a plurality of pads 210 distributed along the circumferential direction and an air duct plate 220 connected between the pads 210. The pads 210 and the air duct plate 220 form a cylindrical structure for connecting the main air ducts of the upper and lower layers, thereby reducing the air volume loss of the bottom fan, significantly accelerating the air flow inside and outside the transformer, and extending the service life of the product.

[0029] Specifically, each of the pads 210 includes an epoxy resin structural member 211 and silicone rubber 212a, 212b. Two bosses 213 are provided on the upper and lower sides of the epoxy resin structural member 211, and the high-voltage coils 111, 121, 131 and the low-voltage coils 112, 122, 132 in each coil group are respectively provided on both sides of the two bosses 213; a positioning groove 214 is provided between the two bosses 213 on the same side, and the insulating tubes 113, 123, 133 are engaged. In the positioning groove 214; one end of the epoxy resin structural member 211 is provided with a chamfer 215, and the other end is provided with a slot 216 arranged in the longitudinal direction, and the two ends of the air duct plate 220 are respectively engaged in the slots 216 of the pad 210 on both sides; the silicone rubber 212a, 212b is attached to the position where the epoxy resin structural member 211 contacts the high-voltage coil 111, 121, 131 or the low-voltage coil 112, 122, 132, specifically, as Figure 3a As shown, combined with Figure 2a and 2b Silicone rubber 212a is positioned on the epoxy resin structural member 211 near chamfer 215, while silicone rubber 212b is positioned on the epoxy resin structural member 211 near slot 216. Silicone rubber 212a and 212b act to reduce vibration and protect the coil. This invention is easy and flexible to manufacture and install, has no impact on the overall transformer structure, and has minimal impact on manufacturing costs. The air duct plate 220 is secured to the spacer 210 via slot 216, eliminating noise during operation and increasing the transformer's overload capacity.

[0030] It should be noted that the high-voltage coils 111, 121, 131, the low-voltage coils 112, 122, 132, the insulating tubes 113, 123, 133, and the core supports 114, 124, 134 in this application have the same structural names and the same structures. Different numbers are only used to indicate different installation positions, and do not indicate different structures.

[0031] In some embodiments, please refer to Figure 4a and 4b The air duct plate 220 has insert plates 221 at both ends that mate with the slots 216. The insert plates 221 cooperate with the slots 216 to achieve a slot-type connection. In some embodiments, the height of the air duct plate 220 is 2mm to 4mm less than that of the spacer 210, facilitating installation and removal. In some embodiments, the slots 216 can be 6mm to 8mm deep to ensure a secure connection between the insert plates 221 and the slots 216. The slots 216 are continuous, with silicone rubber 212b sealing the upper and lower ends.

[0032] In some embodiments, please refer to Figure 5 and Figure 6The guide structure 200 includes four pads 210, and the four pads 210 are evenly distributed along the circumference. Of course, the number and position of the pads 210 correspond to the number and position of the coil groups in each layer of winding.

[0033] The epoxy resin structure 211 is the main supporting structure between the coils. In some embodiments, the boss 213 is 20 mm ± 0.5 mm higher than the same side surface of the epoxy resin structure 211, that is, it is about 10 mm deep into the axial direction of the coil, and is used to limit the position of the coil.

[0034] In some embodiments, the insulating cylinder 113, 123, and 133 is 20 mm to 40 mm higher than the coil group in the axial direction. In this embodiment (10 kV dry-type transformer product), 40 mm is taken to enhance the main insulation between high and low voltage and facilitate heat exchange between the transformer air duct and the outside world.

[0035] like Figure 1 As shown, the present invention also provides a method for installing a dry-type split transformer as described above, which mainly includes the following steps: first, place the lower pad 102 on the high and low voltage clamps (not shown) along the circumferential direction, considering that the low voltage outlet copper bar (copper bar facing upward) affects the installation, first place the high voltage coil 131 on the lower pad 102, then install the insulation tube 133 and the low voltage coil 132 in sequence, after adjusting the position, use the core support bar 134 to firmly fix the low voltage coil 132 and the core (not shown). Then, place the pad 210 at the same circumferential angle as the lower pad 102, and install the air duct plate 220 between the slots 216 of the pad 210, and adjust the relative position; then, install the high voltage coil 121, insulation tube 123, core support bar 124 and low voltage coil 122 in sequence. The specific placement method is the same as the method for placing the lower coil, and will not be repeated here; if the coil group continues to be stacked, continue to install it according to the above order and method, and will not be repeated here. It should be noted that the structure of the upper pad 101 and the lower pad 102 can refer to the pad structure in the prior art, and its structure does not affect the main air duct connection between the upper and lower layers in this application, so this application does not limit its structure.

[0036] In this application, before installing the guide structure 200, the pad 210 is placed circumferentially according to the product layout diagram, and then the inner diameter and thickness of the air duct plate 220 are determined according to the position of the slot 216 on the pad 210. The corresponding air duct plate 220 is selected according to the inner diameter and thickness. Figure 5 As shown, the problem of mismatch between the pad 210 and the air duct plate 220 is avoided.

[0037] In some embodiments, as Figure 6As shown, the air duct plate 220 is cut from a cylinder (which can be an insulating cylinder) whose inner diameter and thickness match the slot 216. For example, the cylinder is divided into four parts in the circumferential direction, and plug-in plates 221 are made on the two edges of the circumference to facilitate insertion into the corresponding slot 216 during assembly, further reducing the difficulty of production and installation and reducing production costs.

[0038] In summary, the dry-type split transformer and its installation method provided by the present invention include at least two layers of windings distributed in the axial direction, each layer of windings includes a plurality of coil groups, each coil group includes high-voltage coils 111, 121, 131 and low-voltage coils 112, 122, 132, and a main air duct (not shown) is provided between the high-voltage coils 111, 121, 131 and the low-voltage coils 112, 122, 132, and an insulating cylinder 113, 123, 133 is provided in the main air duct; a guide structure 200 is provided between the two layers of axially distributed windings, and the guide structure 200 includes a plurality of pads 210 distributed in the circumferential direction and an air duct plate 220 connected between the pads 210, and the pads 210 and the air duct plate 220 enclose a cylindrical structure; each of the pads 210 includes an epoxy resin structural member 211 and a silicone rubber 2 12. Two bosses 213 are respectively provided on the upper and lower sides of the epoxy resin structural member 211, and the high-voltage coils 111, 121, 131 and the low-voltage coils 112, 122, 132 in each coil group are respectively arranged on both sides of the two bosses 213; a positioning groove 214 is provided between the two bosses 213 on the same side, and the insulating tubes 113, 123, 133 are snapped into the positioning groove 214; one end of the epoxy resin structural member 211 is provided with a chamfer 215, and the other end is provided with a longitudinally arranged groove 216, and the two ends of the air duct plate 220 are respectively snapped into the grooves 216 of the pads 210 located on both sides; the silicone rubber 212a, 212b is attached to the position where the epoxy resin structural member 211 contacts the high-voltage coils 111, 121, 131 or the low-voltage coils 112, 122, 132. The present invention utilizes the spacer 210 and the air duct plate 220 to enclose a cylindrical structure for connecting the upper and lower layers of the main air duct, thereby achieving the purpose of reducing the air volume loss of the bottom fan, significantly accelerating the air flow inside and outside the transformer, and extending the service life of the product.

[0039] Obviously, those skilled in the art may make various changes and modifications to the invention without departing from the spirit and scope of the invention. Thus, if such changes and modifications fall within the scope of the claims and their equivalents, the present invention is intended to include such changes and modifications.

Claims

1. A dry-type split transformer, comprising at least two layers of windings distributed axially, each layer of windings comprising a plurality of coil groups, each coil group comprising a high-voltage coil and a low-voltage coil, a main air duct being provided between the high-voltage coil and the low-voltage coil, an insulating cylinder being provided within the main air duct, characterized in that: A guide structure is arranged between the two axially distributed layers of windings, and the guide structure includes a number of pads distributed along the circumferential direction and air duct plates connected between the pads, and the pads and the air duct plates form a cylindrical structure; each of the pads includes an epoxy resin structural member and silicone rubber, and two bosses are respectively provided on the upper and lower sides of the epoxy resin structural member, and the high-voltage coil and the low-voltage coil in each coil group are respectively arranged on both sides of the two bosses; a positioning groove is provided between the two bosses on the same side, and the insulating tube is clamped in the positioning groove; one end of the epoxy resin structural member is provided with a chamfer, and the other end is provided with a slot arranged longitudinally, and the two ends of the air duct plate are respectively clamped in the slots of the pads located on both sides; the silicone rubber is attached to the position where the epoxy resin structural member contacts the high-voltage coil or the low-voltage coil.

2. The dry-type split transformer according to claim 1, characterized in that Both ends of the air duct plate are plug-in plates that match the card slots.

3. The dry-type split transformer according to claim 1 or 2, characterized in that: The depth of the card slot is 6mm to 8mm.

4. The dry-type split transformer according to claim 1, characterized in that The height of the air duct plate is 2 mm to 4 mm smaller than the height of the pad.

5. The dry-type split transformer according to claim 1, characterized in that The guide structure includes four pads, and the four pads are evenly distributed along the circumference.

6. The dry-type split transformer according to claim 1, characterized in that The boss is 20 mm ± 0.5 mm higher than the same side surface of the epoxy resin structural component.

7. The dry-type split transformer according to claim 1, characterized in that The insulating cylinder is 20 mm to 40 mm higher than the coil assembly in the axial direction.

8. A method for installing a dry-type split transformer according to any one of claims 1 to 7, characterized in that: Before installing the guide structure, first place the pads along the circumference according to the product layout diagram, then determine the inner diameter and thickness of the air duct plate according to the position of the slots on the pads, select the corresponding air duct plate according to the inner diameter and thickness, and connect the air duct plate and the pads to form the guide structure.

9. The installation method according to claim 8, wherein: The air duct plate is cut from a cylinder whose inner diameter and thickness match the slot.

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