Dry-type transformer low-voltage winding structure employing heat pipe for heat dissipation at airway

Abstract

The present application belongs to the technical field of dry-type transformers, and particularly relates to a dry-type transformer low-voltage winding structure with heat pipes for heat dissipation at air passages, which comprises a core, the outer edge of the core is provided with a low-voltage coil, the outer edge of the low-voltage coil is provided with a high-voltage coil, the inside of the low-voltage coil is provided with a strut curtain; the inside of the strut curtain is provided with heat pipes, the lower ends of the heat pipes are arranged in the inside of struts, the outside of the struts is provided with insulating struts, and struts are arranged between the heat pipes; the inside of the heat pipes is provided with liquid medium; the strut curtain comprises insulating paper, and the whole strut curtain is arranged in a sandwich curtain structure of 'insulating paper-strut-insulating paper'; and the strut curtain is arranged in a ring shape at the outer edge of the coil winding. The application places detachable heat pipes at the air passages of the low-voltage winding of the dry-type transformer, and the heat pipes absorb heat by gasification of the liquid medium in the heat pipes to dissipate the heat of the low-voltage winding. The application has the advantages of high heat dissipation efficiency, maintenance-free, convenient replacement, and reduced temperature rise of the low-voltage winding.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of dry-type transformers, and particularly relates to a dry-type transformer low-voltage winding structure with heat pipes for heat dissipation at air passages. BACKGROUND

[0002] The winding of a dry-type transformer is cooled by surface air convection and radiation. The low-voltage winding is generally located inside the entire coil, and the cooling condition is poor, which easily leads to excessively high temperature rise of the low-voltage winding and affects the insulation life of the transformer.

[0003] The low-voltage winding has a low voltage grade, and the field strength between air passages is also low. Therefore, heat pipes can be placed at the air passages of the low-voltage winding of the dry-type transformer, and the heat dissipation efficiency is greatly improved by using the phase change heat dissipation principle of the heat pipes, so that the self-cooling temperature rise of the low-voltage winding can be effectively reduced. SUMMARY

[0004] The application aims to provide a dry-type transformer low-voltage winding structure with heat pipes for heat dissipation at air passages, which can place detachable heat pipes at the air passages of the low-voltage winding of the dry-type transformer, and the heat of the low-voltage winding is dissipated by the heat absorption of the gasification of liquid medium in the heat pipes. The application has the advantages of high heat dissipation efficiency, maintenance-free, convenient replacement, and reduced temperature rise of the low-voltage winding.

[0005] The technical scheme adopted by the application is as follows:

[0006] The application provides a dry-type transformer low-voltage winding structure with heat pipes for heat dissipation at air passages, which comprises a core, the outer edge of the core is provided with a low-voltage coil, the outer edge of the low-voltage coil is provided with a high-voltage coil, and the inside of the low-voltage coil is provided with a support strip curtain.

[0007] The inside of the support strip curtain is provided with heat pipes, the lower end of the heat pipes is arranged in the inside of the support strip, the outside of the support strip is provided with an insulating support strip, and support plates are arranged between the heat pipes.

[0008] The inside of the heat pipes is provided with liquid medium.

[0009] The support strip curtain comprises insulating paper, and the whole support strip curtain is arranged in a sandwiched curtain structure of “insulating paper-support strip-insulating paper”.

[0010] The support strip curtain is arranged in a ring shape at the outer edge of the coil winding.

[0011] In a preferred scheme, the whole material of the support strip is arranged as high-thermal-conductivity material.

[0012] In a preferred scheme, grooves are arranged on the two sides of the support strip, the inside of the grooves is connected with the heat pipes 1, and the bottom of the grooves is not through.

[0013] In a preferred embodiment, the two ends of the strut are provided with through grooves, which form heat dissipation channels.

[0014] In a preferred embodiment, the joint surface between the heat pipe and the strut is provided with an elastic rubber pad.

[0015] In a preferred embodiment, the liquid medium uses methanol or ethanol as the heat dissipation liquid inside the heat pipe 1.

[0016] In a preferred embodiment, 1% graphene is added as a heat-conducting filler in the liquid medium.

[0017] In a preferred embodiment, the strut curtain adopts a segmented design, and the length of each segment of the strut curtain matches the axial size of the coil air duct. The spacing of the transverse struts is accurately positioned according to the installation requirements of the heat pipe.

[0018] In a preferred embodiment, the upper end of the heat pipe is a heat dissipation end, and the outer edge of the upper end of the heat pipe is provided with a plurality of heat dissipation fins.

[0019] In a preferred embodiment, the surface of the heat dissipation end of the heat pipe is sprayed with black anti-rust paint.

[0020] The technical effects achieved by the present application are:

[0021] The present application significantly improves the heat dissipation efficiency by the phase change heat dissipation principle of the heat pipe. The liquid medium (such as methanol or ethanol) inside the heat pipe quickly vaporizes when the low-voltage winding generates heat, absorbs heat and migrates to the heat dissipation end through steam, and the synergistic effect of the heat dissipation fins and the black anti-rust paint coating enhances heat radiation and convective heat transfer. The condensed liquid medium flows back to form a cycle, effectively reducing the temperature rise of the low-voltage winding. At the same time, the liquid medium with 1% graphene further optimizes the heat conduction performance, reduces the thermal resistance and the risk of local overheating, and ensures the long-term stable operation of the transformer.

[0022] The present application adopts a sandwich curtain design of "insulating paper-strut-insulating paper", combined with a segmented installation process, so that the strut curtain and the coil air duct are accurately matched, simplifying the winding process and improving the structure fit. The heat pipe is installed in a plug-in manner through the grooves on both sides of the strut, and the elastic rubber pad buffers the thermal expansion stress, which is convenient for maintenance and replacement, and enhances the insulation performance. In addition, this structure supports the modification of existing transformers, and by adding heat pipes and struts at the air duct, the heat dissipation capacity can be improved without overall disassembly, significantly reducing the modification cost.

[0023] The present application adopts high-thermal-conductivity materials (such as aluminum alloy or graphite composite material) for the struts to accelerate heat transfer, and combines with the through groove design to form a heat dissipation channel, which takes into account the lightweight and high-efficiency heat dissipation. The black anti-rust paint coating on the heat pipe heat dissipation end enhances the infrared radiation capacity and corrosion resistance, prolonging the service life of the equipment. The selection of liquid medium and the addition of graphene filler further optimize the starting efficiency and heat transfer uniformity of the heat pipe, ensuring the reliability and low maintenance requirements of the system under complex working conditions. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 is a low-voltage winding structure schematic diagram of a dry-type transformer of an embodiment of the present application using a heat pipe to dissipate heat at an air passage;

[0025] Figure 2 is a heat pipe heat dissipation structure and heat dissipation principle diagram of an embodiment of the present application;

[0026] Figure 3 is a heat pipe modification structure diagram of an embodiment of the present application applied to a finished transformer;

[0027] Figure 4 is a heat pipe strut curtain structure diagram of an embodiment of the present application;

[0028] Figure 5 is a strut curtain installation schematic diagram of an embodiment of the present application.

[0029] In the drawings, the components represented by each reference numeral are listed as follows:

[0030] 1, heat pipe; 2, heat dissipation fin; 3, elastic rubber pad; 4, strut; 5, liquid medium; 6, insulating strut; 7, iron core; 8, high-voltage coil; 9, low-voltage coil; 10, strut plate; 11, insulating paper; 12, strut curtain; 13, coil winding. DETAILED DESCRIPTION

[0031] To make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific embodiments of the present application will be described in detail below with reference to the drawings.

[0032] In the following description, many specific details are set forth in order to provide a thorough understanding of the present application, but the present application can also be implemented in other ways different from those described herein, and those skilled in the art can make similar generalizations without departing from the connotation of the present application, therefore the present application is not limited to the specific embodiments disclosed below.

[0033] Second, the "one embodiment" or "an embodiment" referred to herein can include a particular feature, structure, or characteristic. The various embodiments appearing at different places in the specification are not necessarily all cumulative or alternative embodiments of each other. In other words, "in one preferred embodiment" appearing in different places in the specification does not necessarily refer to the same embodiment, nor is it necessarily a separate or alternative embodiment to other embodiments.

[0034] Third, the present application is described in detail in conjunction with the schematic diagram. In the detailed description of the embodiments of the present application, the cross-sectional view of the device structure is partially enlarged without the general proportion for the convenience of description, and the schematic diagram is only an example, which should not limit the scope of protection of the present application. In addition, the three-dimensional spatial dimensions of length, width and depth should be included in actual production.

[0035] Please refer to Figures 1 to 5 As shown in the figure, the present application provides a low-voltage winding structure of a dry-type transformer using a heat pipe to dissipate heat at the airway, which comprises a core 7, the outer edge of the core 7 is provided with a low-voltage coil 9, the outer edge of the low-voltage coil 9 is provided with a high-voltage coil 8, and the inside of the low-voltage coil 9 is provided with a support strip curtain 12;

[0036] The inside of the support strip curtain 12 is provided with a heat pipe 1, the lower end of the heat pipe 1 is arranged in the inside of the support strip 4, the outside of the support strip 4 is provided with an insulating support strip 6, the insulating support strip 6 plays a fixing and protecting role for the support strip 4, and the support plates 10 are arranged between the heat pipes 1;

[0037] The inside of the heat pipe 1 is provided with a liquid medium 5;

[0038] The support strip curtain 12 comprises insulating paper 11, and the whole of the support strip curtain 12 is arranged in a sandwiched curtain structure of "insulating paper 11-support strip 4-insulating paper 11", two layers of insulating paper 11 made of epoxy resin and a plurality of aluminum alloy support strips 4 are prefabricated through a vacuum pressure impregnation process to form a standardized support strip curtain 12 assembly;

[0039] The support strip curtain 12 is arranged in a ring shape outside the coil winding 13.

[0040] During the winding process of the coil, the support strip curtain 12 is directly laid on the wound coil winding 13, and then the subsequent low-voltage coil 9 and high-voltage coil 8 are wound on the support strip curtain 12, so that the support strip curtain 12 is naturally embedded in the inside of the coil structure. This process simplifies the installation process, improves the installation efficiency of the support strip 4, and at the same time ensures the close fit of the support strip 4 and the wire layer, so as to reduce the thermal resistance of the heat conduction path;

[0041] The Joule heat and eddy current heat generated by the low-voltage coil 9 operation are absorbed at the heat absorption end of the heat pipe 1, causing the liquid medium 5 inside the heat pipe 1 to undergo phase change and vaporization. The steam of the liquid medium 5 migrates to the upper end of the heat pipe 1 under the driving of the pressure difference, releases latent heat through heat exchange with the external air at the upper end of the heat pipe 1, and condenses into liquid. Subsequently, the liquid medium 5 falls back into the lower end of the heat pipe 1 under the combined action of the capillary pumping force and gravity, forming a closed circulation path of the liquid medium 5, and completing the continuous heat transport cycle.

[0042] Meanwhile, the scheme can also be used to modify existing transformer products by adding heat pipes 1 at the air duct to improve the temperature rise of the low-voltage winding. The specific measures are as follows: add insulating paper 11 on both sides of the air duct, insert two heat pipes 1, tighten the heat pipes 1 by hitting a support plate 10 between them, and then stick them firmly.

[0043] Please refer to Figure 2 As shown, the overall material of the support bar 4 is set as a high-thermal-conductivity material, such as aluminum alloy, copper alloy, or graphite composite material, which can significantly optimize the overall thermal performance of the heat pipe 1. For example, in the case of aluminum alloy, a thermal bottleneck is easily formed at the contact interface between the support bar 4 and the heat pipe 1, while a high-thermal-conductivity material can accelerate the longitudinal heat transfer from the evaporation section to the condensation section, reduce the interface temperature difference, and avoid local heat accumulation.

[0044] Please refer to Figure 2 As shown, grooves are opened on both sides of the support bar 4, the inside of the grooves is connected with the heat pipe 1, and the bottom of the groove is not through. Through the design of the grooves, a pluggable heat pipe 1 installation method is realized, so that maintenance personnel can quickly replace or clean the heat pipe 1 without disassembling the transformer, reducing maintenance cost and difficulty.

[0045] Please refer to Figure 2 As shown, through grooves are provided at both ends of the support bar 4, and the through grooves form heat dissipation channels. On the basis of expanding the effective heat dissipation area, the heat radiation and convection heat exchange efficiency are simultaneously improved, not only increasing the heat dissipation area of the metal support bar 4, but also achieving the purpose of lightweight. When the support bars 4 are adjacently arranged, the through grooves can also form air flow channels, further increasing the heat dissipation efficiency.

[0046] Please refer to Figure 2 As shown, an elastic rubber pad 3 is arranged at the joint surface between the heat pipe 1 and the support bar 4. The elastic rubber pad 3 has the functions of insulating medium and mechanical stress buffering, which can effectively inhibit the potential transmission between the heat pipe 1 and the support bar 4, and at the same time compensate for the thermal expansion difference of the heat pipe 1 through elastic deformation to improve the structural stability.

[0047] Please refer to Figure 2As shown, the liquid medium 5 uses methanol or ethanol as the heat dissipation liquid inside the heat pipe 1; the core advantage of using methanol or ethanol as the liquid medium 5 in the heat pipe 1 lies in its excellent phase change characteristics and adaptability: the low boiling points of methanol 64.7℃ and ethanol 78.4℃ can quickly vaporize heat in low-temperature scenarios, and the low surface tension of methanol 22.1mN / m and ethanol 22.3mN / m significantly enhances the capillary return ability and improves the starting efficiency of the heat pipe 1.

[0048] As shown in Figure 2 As shown, 1% graphene is added as a heat-conducting filler in the liquid medium 5, and further adding 1% graphene as a heat-conducting filler on the basis of methanol or ethanol as the liquid medium of the heat pipe 1 can significantly improve the performance of the heat pipe 1: the high thermal conductivity of graphene about 5000W / mK can significantly enhance the heat transfer efficiency of the working medium by constructing a nano-thermal-conducting network, reduce the thermal resistance and accelerate the phase change cycle, thereby improving the thermal response speed and heat transfer uniformity and reducing the risk of local overheating.

[0049] As shown in Figure 4 and Figure 5 As shown, the support curtain 12 adopts a segmented design, and the length of each segment of the support curtain 12 matches the axial size of the coil air duct. The spacing of the transverse support bars 4 is accurately positioned according to the installation requirements of the heat pipe 1, so as to provide accurate installation positions for the heat pipe 1 during installation, thereby facilitating the accurate installation of the heat pipe 1 by the operator.

[0050] As shown in Figures 1 to 5 As shown, the upper end of the heat pipe 1 is the heat dissipation end, and the outer edge of the upper end of the heat pipe 1 is provided with a plurality of heat dissipation fins 2, which are uniformly arranged to form a continuous heat dissipation surface, which can optimize the air flow channel and increase the contact area between the heat pipe 1 and the air. Under the condition of natural convection, it can not only strengthen the heat radiation capacity, but also promote the turbulent motion of air, thereby significantly improving the overall heat dissipation efficiency of the heat pipe 1. This structure design takes into account the heat dissipation performance and space utilization.

[0051] As shown in Figures 1 to 5 As shown, the surface of the heat dissipation end of the heat pipe 1 is sprayed with black anti-rust paint. After the surface of the heat dissipation end of the heat pipe 1 is pretreated in multiple stages, an advanced coating process is used to apply a dark protective coating.

[0052] The composite coating system is composed of a high-molecular-resin base material and a radiation-enhancing material, and forms a dense protective structure through a layered curing process.

[0053] The coating not only meets the corrosion prevention requirements in harsh environments, but also significantly improves the infrared radiation characteristics due to its special surface morphology and material ratio.

[0054] On the heat dissipation end surface, the process treated coating and the fin geometry have a synergistic effect, through the dual action mechanism of enhancing the heat radiation capacity and optimizing the convective heat transfer, the heat dissipation capacity of the heat dissipation system is overall improved.

[0055] The working principle of the present application is that during the winding process, the support strip curtain 12 is directly laid on the wound coil wire 13, and then the subsequent low-voltage coil 9 and high-voltage coil 8 are wound on the support strip curtain 12, so that the support strip curtain 12 is naturally embedded in the inside of the coil structure. This process simplifies the installation process, improves the installation efficiency of the support strip 4, and ensures the close fit of the support strip 4 and the wire layer, so that the thermal resistance of the heat conduction path is reduced.

[0056] At the heat absorption end of the heat pipe 1, the Joule heat and eddy current heat generated during the operation of the low-voltage coil 9 cause the phase change and vaporization of the liquid medium 5 inside the heat pipe 1. The steam of the liquid medium 5 migrates to the upper end along the axial direction of the heat pipe 1 under the driving of the pressure difference, releases latent heat through heat exchange with the external air at the upper end of the heat pipe 1, and condenses the steam of the liquid medium 5 into liquid. Subsequently, the liquid medium 5 falls into the lower end of the heat pipe 1 under the synergistic action of the capillary pumping force and gravity, forming a closed circulation path of the liquid medium 5, and completing the continuous heat transport cycle.

[0057] At the same time, the scheme can also be used for the modification of existing transformer products. The heat pipe 1 is added at the air duct to improve the temperature rise of the low-voltage winding. The specific measures are as follows: add insulating paper 11 on both sides of the air duct, insert two heat pipes 1, tighten the heat pipes 1 by inserting a support plate 10 between them, and then stick them firmly with glue.

[0058] The above is only the preferred embodiment of the present application. It should be pointed out that for ordinary skilled persons in the art, without departing from the principles of the present application, a number of improvements and refinements can be made, which should also be considered within the scope of protection of the present application. The structures, devices and operation methods not specifically described and explained in the present application, such as without special description and limitation, are implemented according to the conventional means in the art.

Claims

1. A dry-type transformer low-voltage winding structure employing heat pipe cooling at the air duct, characterized in that: The iron core (7) is provided with a low-voltage coil (9) at the outer edge, the low-voltage coil (9) is provided with a high-voltage coil (8) at the outer edge, and the low-voltage coil (9) is provided with a support curtain (12) outside; The inside of the support curtain (12) is provided with a heat pipe (1), the lower end of the heat pipe (1) is arranged inside the support (4), the outside of the support (4) is provided with an insulating support (6), and the heat pipes (1) are provided with a support plate (10) therebetween; The inside of the heat pipe (1) is provided with a liquid medium (5); The support curtain (12) comprises an insulating paper (11), and the whole of the support curtain (12) is arranged in a sandwich curtain structure of "insulating paper (11)-support (4)-insulating paper (11)"; The support curtain (12) is arranged in a ring shape outside the coil winding (13); The whole of the support (4) is made of high-thermal-conductivity material; Grooves are formed on both sides of the support (4), the grooves are connected with the heat pipes (1), and the bottoms of the grooves are not through; Through grooves are arranged at both ends of the support (4), and the through grooves form heat dissipation channels.

2. The low-voltage winding structure of a dry-type transformer employing a heat pipe for heat dissipation at the airway according to claim 1, characterized in that: An elastic rubber pad (3) is arranged on the joint surface between the heat pipe (1) and the support (4).

3. The low-voltage winding structure of a dry-type transformer employing a heat pipe for heat dissipation at the airway according to claim 1, characterized in that: Methanol or ethanol is used as the heat dissipation liquid in the heat pipe (1).

4. The low-voltage winding structure of a dry-type transformer employing a heat pipe for heat dissipation at the airway according to claim 1, characterized in that: 1% of graphene is added as a heat conduction filler in the liquid medium (5).

5. The low-voltage winding structure of a dry-type transformer employing a heat pipe for heat dissipation at the airway according to claim 1, characterized in that: The support curtain (12) is designed in a segmented manner, the length of each segment of the support curtain (12) matches the axial size of the coil air duct, and the transverse spacing of the supports (4) is accurately positioned according to the installation requirements of the heat pipes (1).

6. The low voltage winding structure of a dry-type transformer employing heat pipes for heat dissipation at the airway according to claim 1, characterized in that: The upper end of the heat pipe (1) is a heat dissipation end, and a plurality of heat dissipation fins (2) are arranged at the outer edge of the upper end of the heat pipe (1).

7. The low-voltage winding structure of a dry-type transformer employing a heat pipe for heat dissipation at the airway according to claim 1, characterized in that: Black rust-proof paint is sprayed on the surface of the heat dissipation end of the heat pipe (1).

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