CN215417813U

CN215417813U - Heat radiation structure of cake type winding transformer

Info

Publication number: CN215417813U
Application number: CN202120846457.XU
Authority: CN
Inventors: 刘永言; 张倩
Original assignee: Chengdu Shenlan High Technology Development Co ltd
Current assignee: Sichuan Hope Hydropower Development Co Ltd
Priority date: 2021-04-23
Filing date: 2021-04-23
Publication date: 2022-01-04
Anticipated expiration: 2031-04-23

Abstract

The utility model provides a heat dissipation structure for a cake-type winding transformer, which comprises an insulating cylinder, a secondary winding wire cake, a cake frame and an air duct. Gaps with different widths are arranged between the leads of the single secondary winding wire cake along the circumferential direction, the gap is zero in the window of the iron core, and the gap is gradually increased outside the window of the iron core along the direction perpendicular to the front and back symmetrical surfaces of the iron core. The size of the gap between the wires is ensured by the length of the cushion block. The heat dissipation structure increases the heat dissipation area of the secondary winding wire cake lead of the transformer on the premise of not increasing the size of the window of the iron core, improves the heat exchange efficiency, and reduces the temperature of the lead, thereby improving the current-carrying density of the lead, increasing the capacity and reducing the cost of the transformer.

Description

Heat radiation structure of cake type winding transformer

Technical Field

The utility model discloses a heat dissipation structure for a pancake winding transformer, and belongs to the field of dry-type transformer structures.

Background

The life of a transformer is mainly determined by the life of the electrical insulation therein, and most transformer damages and failures are caused by the damages of the insulation. It is statistical that the number of accidents due to various types of insulation faults is about 85% or more of all transformer accidents. The life of the electrical insulation is in turn dependent on the temperature inside the transformer, so reducing the transformer temperature is an effective way to extend its life. When the transformer operates, heat mainly comes from iron loss and copper loss, and the loss is converted into heat to be transmitted outwards, so that the temperature of the transformer body is increased. In order to ensure the normal operation of the transformer, the mode of reducing the heat productivity and timely dissipating the generated heat can be adopted to avoid the damage of the insulation part caused by the overheating inside the transformer. The iron loss is proportional to the mass of the iron core, so that the heat generation can be reduced by reducing the amount of the iron core. The ratio of the external surface area of the small-capacity transformer to the volume of the transformer is relatively large, the self-cooling mode can be adopted for heat dissipation, and the heat can be dissipated through radiation and natural convection. However, as the capacity of the transformer increases, the corresponding heat productivity also increases, and the self-cooling mode cannot solve the problem of internal heat dissipation, and a forced air cooling measure needs to be taken to make cold air flow through the transformer core and the winding to increase the heat dissipation effect. Whether self-cooling or forced cooling, enough heat dissipation area is needed to dissipate heat, so that the larger the transformer capacity is, the larger the heat dissipation area is. In order to increase the internal heat dissipation area of the transformer, CN102982979.A discloses a cake-type coil-wound three-phase transformer, a gap is arranged between every two layers of wire cakes on the upper layer and the lower layer of the transformer, so that the temperature conditions of the upper surface and the lower surface of the wire cakes are improved to a certain extent, but the wires in the wire cakes are still tightly attached and do not dissipate heat fully, and the problems of insufficient heat dissipation surface and low cooling efficiency still exist. In addition, the wire cake is wound in a mode of uniformly increasing gaps among the wires, although the heat dissipation area of the winding is increased, the cross section of an iron core window is correspondingly increased, the using amount of the iron core is increased, the volume of the transformer is increased, and the cost is correspondingly increased.

Disclosure of Invention

The utility model aims to overcome the defects in the prior art, and provides a heat dissipation structure which can effectively increase the heat dissipation area of a secondary winding wire cake conductor on the premise of not increasing the size of a transformer iron core, improve the heat exchange efficiency, reduce the temperature of the conductor, improve the current-carrying density of the conductor, reduce the using amount of the conductor under the same transformer capacity or increase the transformer capacity under the same section size of the conductor, and reduce the using amount of the iron core, thereby reducing the cost of the transformer.

In order to achieve the purpose, the heat dissipation structure of the cake-type winding transformer comprises an insulation cylinder, a plurality of cake frames and a plurality of secondary winding wire cakes, wherein the insulation cylinder takes the axis of an iron core column as a rotating shaft, the cake frames are fixed on the outer side of the insulation cylinder and are regularly distributed along the circumference, the secondary winding wire cakes are supported in clamping grooves of the cake frames and are arranged up and down, and uniform gaps are reserved among wires of the single secondary winding wire cake or gaps with different widths are arranged along the circumferential direction of a coil. The gap is zero in the iron core window, and the gap is gradually increased along the outward direction perpendicular to the front and back symmetric surfaces of the iron core outside the iron core window, namely, the wires are wound sparsely outside the iron core window in a manner that the wires are tightly wound inside the iron core window. The upper and lower gaps of the secondary winding wire cake are determined by the thickness of the supporting strips of the cake frame, and the gaps between the conducting wires are determined by the length of the cushion blocks.

As another improvement of the utility model, the cushion block is provided with a clamping groove for positioning, and the bottom of the groove is provided with a heat-resistant double-sided adhesive tape for fixing the cushion block on the cake frame. The cushion block adopts epoxy glass fiber laminated board, glass fiber reinforced PBT or epoxy diphenyl ether.

As another improvement of the utility model, the leads of a single secondary winding wire cake are concentrically wound in groups, no gap is left between the leads in the group, and a gap is left between the groups, so that the heat dissipation area is increased to the maximum extent, and simultaneously, the use amount of the leads is reduced, and the front and back thickness sizes of the transformer are reduced. When the number of the gaps arranged among the single secondary winding wire cake conductors is n, n is more than or equal to 1 and less than or equal to (the number of turns of the single secondary winding wire cake conductors/2-1), and the width of the gaps is not less than 5 mm.

As another improvement of the utility model, when the primary winding and the secondary winding are arranged inside and outside around the iron core column, the leads of the primary winding wire cake are wound into concentric circles in groups besides the close winding, the number of the groups is more than or equal to 2, and the gap between the groups is more than or equal to 5 mm. The gap between the secondary winding wire cake conductors is zero in the iron core window, and gradually increases along the circumferential direction outside the iron core window and in the direction perpendicular to the outward direction of the front and back symmetrical surfaces of the iron core.

As another improvement of the utility model, the gap between the single secondary winding wire cake wires is gradually increased and then gradually decreased along the circumferential direction outside the window of the iron core and perpendicular to the outward direction of the front and back symmetrical surfaces of the iron core, the decreased gap is not less than 5mm, and the gaps are symmetrically arranged along the left and right vertical surfaces of the iron core column surrounded by the gaps, so as to achieve the purpose of reducing the thickness of the transformer on the premise of meeting the requirement of heat dissipation.

As another improvement of the utility model, all the secondary winding wire cakes arranged along the axial direction of the iron core column are basically aligned with the gaps among the wires along the wind direction of the cooling wind, so that the wind resistance is reduced, and the power consumption of the fan is reduced.

Drawings

The present invention will be described in further detail with reference to the accompanying drawings.

Fig. 1 is a schematic perspective view of a heat dissipation structure of a pancake winding transformer according to the present invention.

Fig. 2 is a sectional view a-a of fig. 1.

Fig. 3 is a partial schematic view of the installation of the secondary winding cake.

Fig. 4 is an enlarged view of a portion I of fig. 3 with a lead removed.

Fig. 5 is a schematic diagram of a coil group winding structure.

Fig. 6 is a schematic structural diagram of the concentric inner and outer arrangement of the primary winding and the secondary winding.

Fig. 7 is a schematic view of a configuration in which the wire gap is increased and then decreased outside the core window.

Fig. 8 is a rotated sectional view B-B of fig. 2.

Fig. 9 is a schematic structural diagram of a first preferred embodiment of a heat dissipation structure of a pancake winding transformer according to the present invention.

Fig. 10 is a schematic structural diagram of a second preferred embodiment of a heat dissipation structure of a pancake winding transformer according to the present invention.

Detailed Description

The following further description is made with reference to the accompanying drawings and specific examples.

Referring to fig. 1, 2 and 3, a heat dissipation structure of a pancake winding transformer includes an insulating cylinder 1 concentric with an iron core column 5, a pancake frame 2, a secondary winding wire cake 3 and an air duct 4. The cake frame 2 is fixed on the outer surface of the insulating cylinder 1 and distributed regularly along the circumference, the secondary winding wire cakes 3 are supported in the clamping grooves 21 of the cake frame 2, and the upper and lower intervals are determined by the height of the supporting bars 22 of the cake frame 2. Gaps 6 which are uniform or have different widths along the circumferential direction of the coil are reserved among the wires 31 of the single secondary winding wire cake 3, and the size of the gaps among the wires is ensured by the length of the cushion block 32.

Referring to fig. 2, the gap 6 between the wires is zero inside the core window 7, and gradually increases outside the core window 7 along the circumferential direction of the coil and in the outward direction perpendicular to the front-rear symmetric plane 8 of the core. The width of the ventilation channel 12 between the air duct 4 and the secondary winding wire cake 3 in the iron core window 7 is W₁W outside the core window 7₂，W₁≥2·W₂。

Referring to fig. 4, the pad 32 is fixed on the cake frame 2 by a slot 321 at the bottom and a double-sided adhesive 323 at the bottom 322 of the pad. The cushion block 32 is made of epoxy glass fiber laminated board, glass fiber reinforced PBT or epoxy diphenyl ether.

Referring to fig. 5, the wires 31 of a single secondary winding cake 3 are wound in groups of concentric windings with no gaps between adjacent wires in a group and gaps 6 between groups.

Referring to fig. 6, when the primary winding 9 and the secondary winding 10 are arranged inside and outside around the core limb 5, the wires of the primary winding wire cake 91 are wound in groups into concentric circles. The gap 6 between the conductors of the secondary winding cake 3 is zero inside the core window 7 and gradually increases in the circumferential direction outside the core window 7 and in the outward direction perpendicular to the front-rear symmetry plane 8 of the core.

Referring to fig. 7, the gaps 6 between the wires 31 of the single secondary winding cake 3 gradually increase and then gradually decrease along the circumferential direction outside the core window 7 and in the outward direction perpendicular to the front-rear symmetrical plane 8 of the core, and the gaps 6 are symmetrically arranged along the left-right vertical plane 11 of the core column surrounded by the gaps 6.

Referring to fig. 8, all the secondary winding wire cakes 3 arranged axially along the same core limb 5 have their respective gaps 6 between the wires 31 aligned correspondingly in the direction of the cooling wind.

Referring to fig. 9, it is a first preferred embodiment of the heat dissipation structure of the pancake winding transformer of the present invention: the three-phase-shifting transformer is used for a 2500kVA/10kV three-phase-shifting transformer, a winding is formed by concentrically stacking a plurality of wire cakes up and down by adopting a continuous wire cake structure, and a primary winding 9 and a secondary winding 10 are arranged inside and outside around an iron core column 5. The wires of the primary winding coil 91 are wound in concentric circles, and 8 turns of the wires of each layer of the primary winding coil 91 are equally divided into two groups of 4 turns, and a uniform gap 6a is left between the two groups, and the value of the gap is 11 mm. The total 18 turns of the conducting wires of the secondary winding wire cake 3 are equally divided into 6 groups, a gap 6 is reserved between every two groups of coils along the radial direction, the gap 6 is zero in an iron core window 7, the gap is gradually increased along the circumferential direction outside the iron core window and in the direction perpendicular to the front and rear symmetrical surfaces 8 of the iron core, and the maximum value of the gap 6 is 11mm at the position where the gap is intersected with the left and right vertical surfaces 11 of the iron core column. The gaps 6 are arranged bilaterally symmetrically along the left and right vertical planes 11 of the core limb 5. The width of the ventilation duct 12 between the air duct 4 and the outer side face of the secondary winding wire cake 3 is 15mm in the iron core window 7 and 7mm outside the iron core window 7. The cushion block 32 is made of epoxy glass fiber laminated board.

The cost of the transformer core and the aluminum conductor of the embodiment is reduced by 15.7 percent compared with the conventional structure.

Referring to fig. 10, there is shown a second preferred embodiment of the heat dissipation structure of the pancake winding transformer according to the present invention: the gap 6 between the lead groups of the secondary winding wire cake 3 is zero at the inner side of an iron core window 7, the gap gradually increases and then gradually decreases along the circumferential direction outside the iron core window and in the direction perpendicular to the outward direction of a front symmetrical plane 8 and a rear symmetrical plane 8 of the iron core, the maximum gap is 11mm when the angle of the gap is 40 degrees with a central plane, and the maximum gap is 5mm when the gap is on a left vertical plane and a right vertical plane 11 of the iron core column. This embodiment reduces the thickness dimension of the transformer by 60mm, accounting for about 6% of the total width.

While the utility model has been described with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the utility model as defined in the appended claims.

Claims

1. The utility model provides a heat radiation structure of cake formula winding transformer, including insulating cylinder (1) with the axis of iron core post (5) as the pivot, fix and be a plurality of cake framves (2) that the rule distributes along the circumference outside the insulating cylinder, support a plurality of secondary winding line cakes (3) and air duct (4) in cake frame draw-in groove (21) by wire (31) and cushion (32) are constituteed, leave even clearance between wire (31) of single secondary winding line cake (3), except leaving even clearance between wire (31) of its characterized in that single secondary winding line cake (3), still along line circle circumference set up the unequal clearance of width (6), the clearance size between the wire is guaranteed by the length of cushion (32).

2. The heat dissipation structure of a pancake winding transformer according to claim 1, wherein the gap (6) between every two adjacent turns of the single secondary winding cake (3) is zero inside the core window (7), and gradually increases outside the core window (7) along the circumferential direction of the coil and in the outward direction perpendicular to the front and back symmetric planes (8) of the core.

3. The heat dissipation structure of a pancake winding transformer according to claim 1, wherein a ventilation duct (12) is left between the air duct (4) and the secondary winding wire cake (3), and the width of the ventilation duct is W in the core window (7)₁W outside the iron core window (7)₂，W₁≥2·W₂。

4. The heat dissipation structure of the pancake winding transformer according to claim 1, wherein the pad (32) is fixed on the pancake base (2) by a slot (321) at the bottom and a double-sided adhesive tape (323) at the bottom (322) of the pad.

5. The heat dissipation structure of a pancake winding transformer as claimed in claim 1, wherein the spacer (32) is made of epoxy glass fiber laminate, glass fiber reinforced PBT or epoxy diphenyl ether.

6. The heat dissipation structure of a pancake winding transformer according to claim 1, wherein the wires (31) of a single secondary winding pancake (3) are concentrically wound in groups, no gap is left between adjacent wires in a group, and a gap (6) is left between groups.

7. The heat dissipation structure of the pancake winding transformer according to claim 1, wherein when the primary winding (9) and the secondary winding (10) are arranged inside and outside around the core limb (5), the wires of the primary winding wire cake (91) are wound in groups into concentric circles besides being densely wound, the number of groups is greater than or equal to 2, and the inter-group gap is greater than or equal to 5 mm; gaps (6) among wires of the secondary winding wire cakes (3) are zero in the iron core window (7), and gradually increase in the outward direction perpendicular to the front and rear symmetrical planes (8) of the iron core along the circumferential direction outside the iron core window (7).

8. The heat dissipation structure of a pancake winding transformer according to claim 1, wherein the gaps (6) between the wires (31) of the single secondary winding pancake (3) are gradually increased and then gradually decreased along the circumferential direction outside the core window (7) and in the outward direction perpendicular to the front and rear symmetric planes (8) of the core, and the gaps (6) are symmetrically arranged along the left and right vertical planes (11) of the core column surrounded by the gaps.