A strong air cooling dry type transformer winding filling structure

Abstract

The application relates to a strong air cooling dry-type transformer winding pouring structure, which comprises a transformer box, a transformer three-phase cylinder, an iron core, an upper iron core clamping piece, a lower iron core clamping piece, a lower wind baffle and a heat pipe heat dissipation assembly, the transformer three-phase cylinder is arranged around the iron core; the iron core is arranged in the transformer box; the lower wind baffle is fixedly arranged in the transformer box, and the lower wind baffle divides the transformer box into an upper air outlet part and a lower air supply part; a plurality of air ventilation channels are arranged in the high-voltage winding epoxy pouring cylinder of the transformer three-phase cylinder in an axial direction; and the heat pipe heat dissipation assembly is arranged at the top of the low-voltage winding epoxy pouring cylinder and the high-voltage winding epoxy pouring cylinder of the transformer three-phase cylinder. The application has the advantages that the air convection heat dissipation area of the epoxy resin is increased, the heat dissipation efficiency of the winding in each pouring part is improved, the air flow path is reasonably designed, the air is fully utilized to take away heat, and the temperature rise of the iron core and the winding is inhibited.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of box-type air-cooled transformer, and particularly relates to a strong air-cooled dry-type transformer winding pouring and sealing structure. BACKGROUND

[0002] In recent years, with the continuous advancement of informationization construction in China and the rapid development of economy, the demand for energy in society continues to rise, and the highest power load of power grid dispatching in Jiangsu Province has broken through 100 million kilowatts for four consecutive years. As one of the key equipment in the power system, power transformers are widely used in power grids of various voltage levels and are the main part of safe transmission and economic distribution of electric energy, playing a crucial role in the safe and stable operation of the power system. The safe and reliable operation of the power transformer is an important guarantee for the stable operation of the power system. According to the insulating medium, the power transformer can be divided into oil-immersed transformer, dry-type transformer and gas transformer. The oil-immersed transformer usually uses mineral oil as the cooling and insulating medium, has good insulation performance, high heat dissipation efficiency, large capacity and other characteristics, but has the safety hidden danger of flammability and explosion in the use process, and the late maintenance cost is large, and is usually used in large and medium-sized substations with high voltage level requirements. The gas transformer mainly refers to the SF6 insulation transformer, which has the advantages of superior fire and explosion prevention performance, small maintenance demand and small land occupation, but has the defects of high process requirement and large investment cost, and has the environmental protection hidden danger of insulation gas leakage, which brings great limitation to the wide use of SF6 insulation transformer.

[0003] With the continuous development of dry-type transformer manufacturing technology, the insulation strength and rated capacity of dry-type transformer are continuously improved, and in addition, the dry-type transformer has the characteristics of superior environmental performance, strong safety and reliability, high operation efficiency and the like, so the proportion of dry-type transformer in distribution network is getting larger and larger. Dry-type transformers are widely used in 35kV and below voltage levels, especially in places close to the load center and places with special requirements for fire safety. In particular in the last 30 years, the proportion of dry-type transformers in distribution transformers has rapidly increased: according to incomplete statistics, in developed countries and regions in the world, dry-type transformers have accounted for 40%-50% of distribution transformers. At present, the use proportion of dry-type transformers in Beijing, Shanghai, Guangzhou and other large cities in China has reached more than 50%, and there is still a trend of continuous increase.

[0004] The dry-type transformer is integrally cast by glass fiber reinforced epoxy resin, has poor heat conduction performance, and air convection heat exchange efficiency is poor, so the dry-type transformer is more prone to local overheating. Compared with the oil-immersed transformer, the capacity of the dry-type transformer is still low, and the thermal time constant is shorter. In the case of transformer overload operation and cooling system failure, the hot spot temperature rises rapidly, causing the insulation material to deteriorate rapidly, reducing the operation reliability. Long-term overheating operation will cause structural damage, and in extreme cases, it may even cause insulation breakdown and internal overheating failure, thereby damaging the equipment and causing huge economic and social losses to the user.

[0005] The hot spot temperature of the dry-type transformer is an important indicator reflecting the health level of the transformer, and is the result of the mutual coupling of electromagnetic field, temperature field and flow field. If the dry-type transformer can be analyzed by multi-physical field coupling, the distribution characteristics of the electromagnetic field, temperature field and flow field of the dry-type transformer can be accurately calculated, and the influence of forced convection heat exchange mode on the cooling effect of the transformer can be explored, which has very important value for the safe operation of the dry-type transformer. In order to meet the increasing demand for rapid calculation and real-time evaluation of the hot spot temperature of the dry-type transformer, it is urgent to simplify the multi-physical field coupling model based on the thermoelectric analogy theory, to finely construct the thermal circuit model of the dry-type transformer, and to optimize the thermal circuit model parameters through the multi-physical field coupling calculation results, and to carry out the temperature rise modeling research of the dry-type transformer.

[0006] When the dry-type transformer is running, the internal core, coil and metal components will generate losses, and the load carried will change, so the losses of the transformer will also change accordingly. All these losses will cause the dry-type transformer to heat up and the temperature to rise. Excessive temperature will reduce the efficiency of the transformer and shorten the service life of the transformer. As can be seen from the above analysis, whether the transformer can work normally depends on the cooling system of the transformer. The utilization rate of the fluid domain in the box of the traditional dry-type transformer air cooling system is low, which causes the temperature of the transformer to rise and fail, and reduces the reliability of the transformer. Therefore, it is urgent to provide a dry-type transformer winding pouring end forced air cooling structure.

[0007] Invention purposes

[0008] The present application provides a dry-type transformer winding pouring end forced air cooling structure to solve the problem that the dry-type transformer in the prior art usually adopts a closed design, the internal space is relatively closed, and the heat dissipation surface area is limited, resulting in lower heat dissipation efficiency than open-type transformers. This may cause temperature rise problems during long-term operation or high load.

[0009] To achieve the above purpose, the present application provides the following technical solutions:

[0010] A new cooling system of high and low voltage winding adopting epoxy resin pouring technology, first, the epoxy resin pouring of high and low voltage winding adopts rectangular slot structure, increases the axial ventilation and heat dissipation area; in view of the problem of high temperature rise of winding end in forced ventilation cooling system, a plurality of heat pipes are connected in parallel to increase the heat dissipation area of winding end; secondly, the air flow path is reasonably designed, and the heat carried by air is fully utilized. Increase the utilization rate of heat dissipation area and air, improve the heat dissipation efficiency of winding; design high pressure outer end insulation cylinder to force air to flow through the outside of high pressure epoxy resin pouring cylinder, increase the size of insulation cylinder to make it 10mm away from the core window, make a lot of air flow through the upper end of the core to reduce the problem of local overheating of the core. At the same time, the mechanical structure of the transformer is optimized, which is helpful to reduce the vibration or deformation problem that may be encountered in the use process of the transformer, and enhance the durability and safety of the equipment.

[0011] To achieve the above object, the present application provides the following technical scheme:

[0012] A strong air cooling dry-type transformer winding pouring structure, comprising a transformer box, a transformer three-phase cylinder, a core, an upper core clamp, a lower core clamp, a lower baffle and a heat pipe heat dissipation assembly, the transformer three-phase cylinder is provided with a plurality of, and each transformer three-phase cylinder is arranged around the core;

[0013] The core is arranged in the transformer box through the upper core clamp and the lower core clamp;

[0014] The lower baffle is fixedly arranged in the transformer box, the lower baffle divides the transformer box into an upper air outlet part and a lower air supply part, the lower air supply part is provided with an air inlet, and the lower baffle is arranged on the outer wall of the transformer three-phase cylinder;

[0015] The upper air outlet part of the transformer box is provided with a plurality of air outlets;

[0016] A plurality of ventilation channels are arranged in the high voltage winding epoxy pouring cylinder of the transformer three-phase cylinder along the axial direction;

[0017] The heat pipe heat dissipation assembly is arranged at the top of the low voltage winding epoxy pouring cylinder and the high voltage winding epoxy pouring cylinder of the transformer three-phase cylinder.

[0018] As a further description of the above scheme, the upper core clamp comprises a fixed plate and a first connecting bolt, the fixed plate is provided with two, and the two fixed plates are arranged in parallel, and the two ends of the fixed plate are fixedly arranged in the interior of the transformer box; the two fixed plates are connected through the first connecting bolt, when the core is installed, the two fixed plates of the upper core clamp are fixed with the upper part of the core through the first connecting bolt;

[0019] The lower iron core clamping piece and the upper iron core clamping piece are identical in structure, the lower iron core clamping piece comprises a fixed plate and a second connecting bolt, two fixed plates are provided and are arranged in parallel, and the two ends of the fixed plate are fixedly arranged in the interior of the transformer box body; the two fixed plates are connected through the second connecting bolt, and when the iron core is installed, the two fixed plates of the lower iron core clamping piece are fixed to the lower part of the iron core through the second connecting bolt.

[0020] As a further description of the above scheme, the heat pipe heat dissipation assembly comprises a heat pipe, a heat pipe heat dissipation fin and a heat dissipation rib, the heat pipe comprises a heat absorption section and a heat dissipation section; the heat pipe heat dissipation fin is arranged on the heat dissipation section of the heat pipe, the heat pipe heat dissipation fin comprises a plurality of blades, and the blades are arranged on the heat pipe heat dissipation fin at intervals; the heat dissipation rib is arranged on the heat absorption section of the heat pipe at an angle, and the other end of the heat dissipation rib extends into the epoxy resin filling glue of the low-voltage winding epoxy filling cylinder or the high-voltage winding epoxy filling cylinder.

[0021] As a further description of the above scheme, the lower wind deflector is provided with a hole matched with the transformer three-phase cylinder, the transformer three-phase cylinder comprises, from the inside to the outside, a low-voltage winding epoxy filling cylinder, a low-voltage winding insulation cylinder, a high-voltage winding insulation cylinder, a high-voltage winding epoxy filling cylinder and a high-voltage outer insulation cylinder, the lower part of the high-voltage outer insulation cylinder is fixedly connected with the inner wall of the hole of the lower wind deflector; a plurality of through ventilation channels are arranged in the high-voltage winding epoxy filling cylinder at intervals, the ventilation channels are arranged along the height direction of the high-voltage winding epoxy filling cylinder, first protrusions are arranged on the outer wall and the inner wall of the high-voltage winding epoxy filling cylinder at intervals in the circumferential direction, the first protrusions are arranged along the height direction of the high-voltage winding epoxy filling cylinder, and every two adjacent first protrusions form a first ventilation groove; a plurality of second protrusions are arranged on the inner wall and the outer wall of the low-voltage winding epoxy filling cylinder at intervals in the circumferential direction, the second protrusions are arranged along the height direction of the low-voltage winding epoxy filling cylinder, and every two adjacent second protrusions form a second ventilation groove; the cross-sectional shape of the second protrusions and the first protrusions is rectangular, sawtooth-shaped, trapezoidal, semicircular or parabolic.

[0022] As a further description of the above scheme, the strong wind cold-dry type transformer winding filling structure further comprises an upper end pressing block and a lower end pressing block, the upper end pressing block is provided with a plurality of upper end pressing blocks, each upper end pressing block comprises a pressing block body and a rib plate, a clamping groove is formed in the bottom of the pressing block body, and the pressing block body is clamped and matched with the top of the low-voltage winding insulation cylinder or the high-voltage winding insulation cylinder through the clamping groove; the rib plate is fixedly arranged on the pressing block body through a bolt, and the rib plate is fixedly connected with the fixed plate of the upper iron core clamping piece.

[0023] The lower end pressing block is provided with a plurality of lower end pressing blocks, each of which comprises a pressing block body and a rib plate, the top of the pressing block body is provided with a clamping groove, and the pressing block body is clamped and matched with the top of the low-voltage winding insulation cylinder or the high-voltage winding insulation cylinder through the clamping groove; the rib plate is fixedly arranged on the body through bolts, and the rib plate is fixedly connected with the fixed plate of the lower core clamping piece.

[0024] As a further description of the above scheme, the top of the low-voltage winding insulation cylinder and the high-voltage winding insulation cylinder is provided with an insulation cylinder upper end wind shield; wherein the bottom of the upper end pressing block is provided with a clamping groove matched with the insulation cylinder upper end wind shield, and the upper end pressing block is clamped and matched with the insulation cylinder upper end wind shield.

[0025] As a further description of the above scheme, the bottom of the low-voltage winding insulation cylinder and the high-voltage winding insulation cylinder is provided with an insulation wind shield; the top of the lower end pressing block is provided with a clamping groove matched with the insulation wind shield, and the lower end pressing block is clamped and matched with the insulation wind shield.

[0026] As a further description of the above scheme, the strong air cooling dry-type transformer winding filling structure further comprises an upper partial flow wind shield, one end of the upper partial flow wind shield is fixedly arranged in the interior of the transformer tank, the other end of the upper partial flow wind shield abuts against the side wall of the fixed plate of the upper core clamping piece, and the upper partial flow wind shield is located above the lower wind shield; the bottom height of the plurality of air outlets is higher than the top height of the transformer three-phase cylinder.

[0027] As a further description of the above scheme, when the transformer tank is cooled, the path of the cooling air is as follows: the first air path is discharged from the tank through the space between the high-voltage outer insulation cylinder and the high-voltage winding epoxy filling cylinder; the second air path carries away the temperature generated by the operation of the high-voltage winding through the high-voltage winding epoxy resin air duct; the third air path is discharged from the tank through the space between the high-voltage winding epoxy filling cylinder and the low-voltage winding epoxy filling cylinder; the fourth air path is discharged from the tank through the gap between the inner side of the low-voltage winding epoxy filling cylinder and the outer surface of the core, the gap between the low-voltage winding insulation cylinder, the high-voltage winding insulation cylinder and the high-voltage winding epoxy filling cylinder, and the gap between the low-voltage winding epoxy filling cylinder and the low-voltage winding insulation cylinder and the high-voltage winding insulation cylinder.

[0028] Advantages and effects of the present application:

[0029] The box type air-cooled transformer of the design is provided with the working principle of three air draught fans to realize the strong air flow field, the upper and lower air baffle plates are increased to improve the heat dissipation efficiency, the bottom insulation air baffle plate is designed to make the air flow through the epoxy resin filling tubes of the high and low voltage windings and the core to reduce the temperature of the core and the windings, the shape of the filling glue of the high and low voltage windings is changed to increase the heat dissipation area and effectively reduce the temperature of the high and low voltage windings. The high and low voltage winding epoxy resin pipe air duct heat pipe has excellent heat conduction performance and can efficiently transmit heat. Compared with the traditional heat dissipation mode, the heat pipe can quickly transmit heat from the heat source to the radiator or cooling system to improve the heat management efficiency. BRIEF DESCRIPTION OF DRAWINGS

[0030] Figure 1 It is a structure diagram of the strong air-cooled dry-type transformer winding filling structure of the embodiment of the application;

[0031] Figure 2 It is a top view of the high voltage winding epoxy resin filling tube of the embodiment of the application;

[0032] Figure 3 It is a perspective view of the high voltage winding epoxy resin filling tube of the embodiment of the application;

[0033] Figure 4 It is a top view of the low voltage winding epoxy resin filling tube of the embodiment of the application;

[0034] Figure 5 It is a perspective view of the low voltage winding epoxy resin filling tube of the embodiment of the application;

[0035] Figure 6 It is a transformer three-dimensional simulation winding temperature rise diagram of the embodiment of the application;

[0036] Figure 7 It is a heat pipe working schematic diagram of the embodiment of the application;

[0037] Figure 8 It is a heat pipe working principle diagram of the embodiment of the application;

[0038] Figure 9 It is a curve of the influence of the contact gap of the heat absorption section or the heat release section of the heat pipe of the embodiment of the application on the equivalent thermal conductivity coefficient;

[0039] Figure 10 It is a curve of the influence of the contact gap of the heat absorption section and the heat release section of the heat pipe of the embodiment of the application on the equivalent thermal conductivity coefficient;

[0040] Figure 11 It is a heat pipe assembly diagram of the embodiment of the application;

[0041] Figure 12 It is a heat pipe assembly perspective view of the embodiment of the application;

[0042] Figure 13 Three-dimensional simulation of core temperature of transformer for the embodiment of the present application;

[0043] Figure 14 Assembly drawing of upper end pressing block for the embodiment of the present application;

[0044] Figure 15 Assembly drawing of lower end pressing block for the embodiment of the present application;

[0045] Figure 16 Assembly drawing of single-phase insulation cylinder for the embodiment of the present application;

[0046] Figure 17 Assembly drawing of upper end pressing block for the embodiment of the present application;

[0047] Figure 18 Assembly drawing of core for the embodiment of the present application;

[0048] Figure 19 Partial assembly drawing of clamp for the embodiment of the present application;

[0049] Figure 20 Assembly drawing of group insulation for the embodiment of the present application;

[0050] Figure 21 Insulation baffle drawing for the embodiment of the present application;

[0051] Figure 22 Sectional view of insulation cylinder upper end baffle for the embodiment of the present application;

[0052] Figure 23 Assembly drawing of box for the embodiment of the present application;

[0053] Figure 24 Two-dimensional air flow schematic for single phase for the embodiment of the present application.

[0054] In the drawings, the components represented by the respective reference numerals are listed as follows:

[0055] 1. upper core clamp, 2. lower core clamp, 3. upper air flow baffle, 4. lower air flow baffle, 5. insulation baffle, 6. upper end pressing block, 7. lower end pressing block, 8. rib plate, 9. core, 10. high voltage winding outer insulation cylinder, 11. high voltage winding insulation cylinder, 12. low voltage winding epoxy resin potting cylinder, 13. high voltage winding epoxy resin potting cylinder, 14. baffle fixing member, 15. nut, 16. gasket, 17. first connecting bolt, 18. second connecting bolt, 19. transformer box, 20. air outlet, 23. lower end air inlet, 24. epoxy resin axial air vent, 26. high voltage winding epoxy resin air vent, 28. heat pipe, 29. heat pipe fin, 33. air, 34. heat dissipation rib, 35. insulation cylinder upper end baffle. Detailed Implementation

[0056] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0057] like Figures 1-16 As shown, a wind-cooled dry-type transformer winding encapsulation structure includes a transformer housing 19, a three-phase transformer casing, an iron core 9, an upper iron core clamp 1, a lower iron core clamp 2, and a lower wind baffle 4.

[0058] The transformer has multiple three-phase cylinders, with an air inlet 23 in the lower air supply section, and each transformer three-phase cylinder is arranged around the iron core 9.

[0059] The iron core 9 is installed inside the transformer housing 19 via the upper iron core clamp 1 and the lower iron core clamp 2;

[0060] The lower baffle plate 4 is fixedly installed inside the transformer housing 19, dividing the transformer housing 19 into an upper air outlet section and a lower air supply section, and is fitted onto the outer wall of the transformer three-phase winding. The upper air outlet section of the transformer housing 19 has several air outlets 20. Several ventilation channels are axially formed inside the epoxy potting cylinder of the high-voltage winding of the transformer three-phase winding. This design adds an upper heat pipe: a highly efficient heat transfer device that utilizes the phase change process (evaporation and condensation) of a liquid to transfer heat. It is typically composed of a sealed metal pipe filled with a working fluid (usually a liquid medium). The function of the heat pipe is to quickly and evenly transfer the heat generated at the upper end to the air, achieving thermal management and control, and solving problems such as localized overheating at the upper end. Secondly, the design considers the high-voltage external insulation and the location of the housing air outlets: adding a high-voltage external insulation cylinder, changing the size of the insulation cylinder to extend beyond the epoxy potting cylinder, and changing the location of the housing air outlets. This design improves airflow distribution within the enclosure, ensuring effective cooling airflow over the upper part of the core 9, thereby reducing the temperature rise of the core 9. Secondly, the winding potting design changes the winding shape, increasing its strength and heat-receiving area, thus improving the transformer's heat dissipation performance. This modification helps suppress winding temperature rise, effectively reducing the transformer's operating temperature and improving equipment reliability and lifespan. Finally, the design incorporates epoxy resin axial ventilation slots: the appearance design utilizes epoxy resin axial ventilation slots, a shape that not only improves heat dissipation but also reduces the amount of potting material used, achieving both economic and environmental benefits.

[0061] The iron core upper clamp 1 of the embodiment of the present application comprises fixing plates and a first connecting bolt 17, wherein the fixing plates are provided in two and arranged in parallel, and the two ends of the fixing plates are fixedly arranged in the interior of the transformer box 19; the two fixing plates are connected through the first connecting bolt 17, and when the iron core 9 is installed, the two fixing plates of the iron core upper clamp 1 are fixed to the upper part of the iron core 9 through the first connecting bolt 17.

[0062] The iron core lower clamp 2 is identical in structure to the iron core upper clamp 1, and the iron core lower clamp 2 comprises fixing plates and a second connecting bolt 18, wherein the fixing plates are provided in two and arranged in parallel, and the two ends of the fixing plates are fixedly arranged in the interior of the transformer box 19; the two fixing plates are connected through the second connecting bolt 18, and when the iron core 9 is installed, the two fixing plates of the iron core lower clamp 2 are fixed to the lower part of the iron core 9 through the second connecting bolt 18.

[0063] The heat pipe heat dissipation assembly of the present application comprises a heat pipe 28, a heat pipe heat dissipation fin and a heat dissipation rib, wherein the heat pipe 28 comprises a heat absorbing section and a heat radiating section; the heat pipe heat dissipation fin is arranged on the heat radiating section of the heat pipe 28, and the heat pipe heat dissipation fin comprises a plurality of blades which are arranged at intervals on the heat pipe heat dissipation fin; the heat dissipation rib is arranged obliquely on the heat absorbing section of the heat pipe 28, and the other end of the heat dissipation rib extends into the epoxy resin filling glue of the low-voltage winding epoxy filling cylinder 12 or the high-voltage winding epoxy filling cylinder 13.

[0064] As shown in the three-dimensional simulation winding temperature rise diagram of the transformer, the temperature rise of the upper end part is relatively high, and there may be defects in the design or manufacturing process of the transformer, such as improper material selection, manufacturing process problems, etc., resulting in uneven heat distribution or local overheating in some parts of the top end, and the heat pipe 28 is added to solve the above problems. Figure 7 The connection relationship between the heat pipe 28 and the heat pipe heat dissipation fin 29 is welding. According to the heat transfer process of the heat pipe, it can be divided into three sections in the axial direction, i.e. the heat absorbing section, the heat exchanging section and the heat releasing section. It can be divided into three layers in the radial direction, i.e. the shell, the wick structure and the vapor chamber. As shown in Figure 10 The heat transfer in the heat pipe can be described by three processes. Heat is first absorbed in the heat absorbing section, then transferred through the adiabatic section, and finally cooled by the cooling medium in the heat releasing section. Figure 7

[0065] As shown in the working principle, Figure 8 The heat absorbing section of the heat pipe is in contact with the heat source, and the heat flow is transferred to the heat pipe shell through the contact thermal resistance R between the heat source and the heat pipe shell. The radial thermal resistance of the heat absorbing section is R 1a The contact thermal resistance R 1b between the heat sink and the heat pipe shell. The radial thermal resistance of the heat absorbing section is R 2a The radial thermal resistance of the heat pipe shell of the heat releasing section is R 2b The radial thermal resistance of the wick structure of the heat absorbing section is R​3a The radial thermal resistance of the candlewick structure of the heat releasing section is R 3b The liquid working medium evaporates into gas working medium in the heat absorbing section. The radial thermal resistance is R 4a The gas working medium condenses into liquid working medium in the heat releasing section. The radial thermal resistance is R 4b The axial heat transfer resistance of the heat pipe shell is R5. The axial thermal resistance of the candlewick structure is R6. The axial heat transfer resistance of the gas working medium is R7. The working medium of the heat pipe should have the characteristics of high latent heat of vaporization, high thermal conductivity, large surface tension, low viscosity, good wettability, etc. Deionized water is a commonly used working medium of the heat pipe. In addition, ethanol and acetone are often used as working medium of the heat pipe, but there is a certain gap in the latent heat and thermal conductivity of vaporized water and deionized water. The contact thermal resistance between the heat source and the shell. The heat absorbing section of the heat pipe is located in the high and low pressure epoxy resin filling groove. Due to the processing technology, the diameter of the heat pipe is smaller than the diameter of the heat source, forming an air gap, so that the contact thermal resistance between the heat pipe and the heat source is d1 in thickness.

[0066]

[0067] In the formula, D1 is the outer diameter of the heat pipe, λ air is the thermal conductivity of air, and L2 is the length of the heat absorbing section of the heat pipe, that is, the length of the part in contact with the heat source. The radial thermal resistance of the heat absorbing section shell. The radial thermal resistance of the heat absorbing section shell is similar to the contact thermal resistance, and the radial thermal resistance R 2a can be expressed as:

[0068]

[0069] In the formula, D2 is the inner diameter of the heat pipe shell, λ1 is the thermal conductivity of the heat pipe shell, and L2 is the length of the heat absorbing section of the heat pipe. The radial thermal resistance of the candlewick structure. The radial thermal resistance is similar to the contact thermal resistance, and the radial thermal resistance R 3a of the candlewick structure can be expressed as:

[0070]

[0071] In the formula, D3 is the inner diameter of the candlewick structure, λ2 is the thermal conductivity of the candlewick structure, which can be calculated by referring to the commonly used parallel equivalent thermal conductivity coefficient model of the candlewick structure. Because the working temperature of the heat pipe is stable, the physical parameters of the liquid change little with temperature. Therefore, the influence of temperature on the equivalent thermal conductivity coefficient of the candlewick structure is ignored. The thermal resistance of the evaporation of the liquid working medium. The liquid working medium heated in the heat pipe begins to evaporate into gas, so there is a heat transfer process at the gas-liquid interface. According to the molecular motion theory, the thermal resistance of heat transfer can be expressed as:

[0072]

[0073] In the formula, R V is the gas constant of the gaseous working medium, T V is the vapor temperature, and Qr For the latent heat of the working medium vaporization, p V For the gas pressure.

[0074] Because the shell of the heat pipe is thin, and the shell is generally made of copper or aluminum and other materials with high thermal conductivity, the temperature difference between the steam and the shell is small, and the temperature difference is generally less than 0.5°C. Therefore, the shell temperature is taken as the steam temperature T V .

[0075]

[0076] In the formula, R is the gas universal constant, R=8.314 J / (K⋅mol), m is the molar mass of the gas, and the heat pipe shell axial thermal resistance. The heat absorbed by the heat absorption section of the heat pipe is partially transferred through the vaporization heat absorption process, and partially transferred through the heat pipe shell axial direction. Therefore, according to the definition of thermal resistance, the heat pipe shell axial heat resistance R5 is:

[0077]

[0078] In the formula, L1 is the total length of the heat pipe, and L3 is the length of the heat release section. The axial thermal resistance of the wick structure. The axial thermal resistance of the wick structure is similar to the axial thermal resistance of the shell, and the axial thermal resistance of the wick structure can be represented as R6:

[0079]

[0080] Gas working medium liquefaction resistance. The gas working medium flows to the heat release section under the action of internal pressure. According to the theory of fluid mechanics[, the thermal resistance generated by the axial flow of the gas can be represented as R7:

[0081]

[0082]

[0083] In the formula, μ v is the viscosity coefficient of the steam working medium, and ρ v is the density of the gas working medium. Considering the symmetry of the heat network, only the lengths of the heat absorption section and the heat release section are different, and the thermal resistance R 1b ~R 4b can be obtained. At the same time, since evaporation and liquefaction are reversible, the thermal resistance of condensation and vaporization is the same. When the length of the heat absorption section and the length of the heat release section are the same (i.e. L2=L3), R 1a =R 1b , R 2a =R 2b , R 3a =R 3b , R 4a =R 4b . The total heat pipe resistance can be represented as R A11 :

[0084]

[0085] To simplify the heat transfer process of the heat pipe, the heat pipe is equivalent to a solid with large thermal conductivity and isotropy. The equivalent thermal conductivity of the heat pipe is λ eq , which ensures that the thermal resistance of the heat pipe before and after the equivalent is unchanged. The equivalent thermal conductivity can be expressed as λ eq :

[0086]

[0087] where R eq is the equivalent thermal resistance of the heat pipe, L eq and S eq are the equivalent transfer length and heat transfer area of the heat pipe, respectively.

[0088] When two different solids are in contact with each other, a contact thermal resistance will be generated. Research has found that the contact thermal resistance between the heat absorption section and the heat release section has a great influence on the equivalent thermal conductivity of the heat pipe. Therefore, the variation law of the equivalent thermal conductivity with the contact gap at one end and the contact gap at both ends of the heat pipe is considered respectively. In this paper, the influence of the size of the contact gap and the thermal conductivity of the material in the contact gap on the equivalent thermal conductivity of the heat pipe is considered. For example, the outer diameter D1 is 10 mm, the length L1 is 300 mm, the length of the heat absorption section and the heat release section L2 and L3 is 150 mm, the shell thickness is 1 mm, and the core structure thickness is 0.5 mm.

[0089] Figure 10 The curves showing the influence of the contact gap of the heat absorption section or the heat release section on the equivalent thermal conductivity are shown, where 0.0204 W / (m·K) is the thermal conductivity of air. With the increase of the contact gap, the equivalent thermal conductivity of the heat pipe gradually decreases, and the contact thermal resistance has a great influence on the thermal conductivity. When the contact gap reaches 0.1 mm, the equivalent thermal conductivity of the heat pipe is only 1818 W / (m·K). The influence of different thermal conductivities of the filler in the contact gap on the heat pipe is analyzed. When the thermal conductivity in the contact gap increases from 0.0204 to 0.1, 0.5 and 1.0 W / (m·K), the equivalent thermal conductivity of the heat pipe can reach 7203, 17004 and 20676 W / (m·K).

[0090] Figure 11It is shown that the contact gap between the heat absorption section and the heat dissipation section of the heat pipe 28 is also taken into account. Similarly, taking a contact gap of 0.1 mm as an example, when the thermal conductivity of the contact gap increases from 0.0204 to 0.1, 0.5 and 1.0 W / (m·K), the equivalent thermal conductivity of the heat pipe can reach 4051, 12547 and 17014 W / (m·K). It can be seen that the contact resistance and thermal conductivity of the filler have a more serious impact on the equivalent thermal conductivity of the heat pipe. Therefore, in practical applications, by filling the contact gap with thermal conductive glue, the influence of the heat pipe contact resistance on the cooling performance can be reduced.

[0091] Figure 12A two-dimensional diagram is assembled for the heat pipe and the heat pipe fin. The heat pipe 28 is in a long rectangular shape, with a length of 12mm, a width of 3mm, and a height of 450mm. The heat pipe is divided into an absorption section and a heat dissipation section, wherein the absorption section is located at the lower end and has a length of 300mm; the heat dissipation section is located at the upper end and has a length of 150mm. The heat pipe fin 29 is arranged on both sides of the heat dissipation section at the upper end of the heat pipe, which aims to increase the heat dissipation capacity. Each heat pipe fin has 9 blades, with a length of 4.5mm, a width of 0.7mm, a height of 150mm, and a spacing of 0.7mm between the blades. At one end of the absorption section, 3 rows and 19 columns of heat absorption ribs 34 are arranged, with a diameter of 1.3mm, a length of 3mm, and a 45° angle with the vertical direction. These heat dissipation ribs penetrate into the epoxy resin pouring glue and can better contact the epoxy resin pouring cylinder, thereby improving the heat absorption efficiency of the absorption section. Between the heat absorption section and the heat dissipation section of the heat pipe, a fillet structure with a length of 6mm and a radius of 5mm is arranged. The heat pipe fins are arranged on both sides of the heat dissipation section, but due to the existence of the epoxy resin pouring cylinder, only one side of the heat pipe fin has wind flowing through, and the other side will not have a large amount of wind passing through, thereby reducing the heat dissipation effect of the heat pipe. The designed fillet structure effectively solves the problem that one side of the heat pipe fin has no wind flowing through, greatly improving the heat dissipation performance of the heat pipe; at the same time, the insulation material in the transformer is very sensitive to temperature. Through effective heat pipe design, the working temperature of the internal components of the transformer can be reduced, the service life of the insulation material can be prolonged, and the insulation aging and damage caused by overheating can be reduced; secondly, the heat pipe can help maintain the appropriate working temperature range of the transformer oil, which is one of the key factors to maintain the normal operation of the transformer and improve its efficiency. Through effective heat pipe design, the stable working temperature of the transformer can be maintained under different load conditions; thirdly, the heat pipe design and heat management of the present application can enable the transformer to carry higher load under the same size, thereby improving its rated capacity. This technical optimization can improve the power density and performance of the equipment without increasing the size of the equipment; finally, the heat pipe helps to achieve the heat balance inside and outside the transformer. By effectively conducting heat to the external environment or heat dissipation system, the working temperature of the transformer can be better controlled to ensure its operation within the design range. This is very important for long-term stable operation and prolonging the service life of the equipment.

[0092] The lower baffle plate 4 of the embodiment of the present application is provided with a hole matched with a transformer three-phase cylinder, wherein the transformer three-phase cylinder comprises, from inside to outside, a low-voltage winding epoxy pouring cylinder 12, a low-voltage winding insulation cylinder, a high-voltage winding insulation cylinder 11, a high-voltage winding epoxy pouring cylinder 13 and a high-voltage outer insulation cylinder 10, the lower part of the high-voltage outer insulation cylinder 10 is fixedly connected with the inner wall of the hole of the lower baffle plate 4, a plurality of through ventilation channels are arranged in the high-voltage winding epoxy pouring cylinder 13, the ventilation channels are arranged along the height direction of the high-voltage winding epoxy pouring cylinder 13, the first protrusions are arranged along the height direction of the high-voltage winding epoxy pouring cylinder 13, and each two adjacent first protrusions form a first ventilation groove, the inner wall and the outer wall of the low-voltage winding epoxy pouring cylinder 12 are both circumferentially arranged with a plurality of second protrusions, the second protrusions are arranged along the height direction of the low-voltage winding epoxy pouring cylinder 12, and each two adjacent second protrusions form a second ventilation groove, and the cross-sectional shape of the second protrusions and the first protrusions is rectangular, sawtooth-shaped, trapezoidal, semicircular or parabolic. The inner wall and the outer wall of the high-voltage winding epoxy pouring cylinder 13 and the low-voltage winding epoxy pouring cylinder 12 are respectively provided with a plurality of first ventilation grooves and second ventilation grooves, which improves the heat dissipation area of the high-voltage winding epoxy pouring cylinder 13 and the low-voltage winding epoxy pouring cylinder 12, and makes the cooling effect better. Meanwhile, the high-voltage winding epoxy pouring cylinder 13 is arranged with a plurality of through ventilation channels, which can also introduce cooling air into the high-voltage winding epoxy pouring cylinder 13, so that the cooling effect is better, and the amount of pouring material is also reduced.

[0093] The winding pouring structure of the strong-wind cold-drying type transformer of the embodiment of the present application further comprises upper end pressing blocks 6 and lower end pressing blocks 7, wherein the upper end pressing blocks 6 are provided in plurality, each upper end pressing block 6 comprises a pressing block body and a rib plate 8, wherein the bottom of the pressing block body is provided with a clamping groove, the clamping groove is clamped and matched with the top of the low-voltage winding insulation cylinder and the high-voltage winding insulation cylinder 11, and the rib plate 8 is fixedly arranged on the pressing block body through bolts, and the rib plate 8 is fixedly connected with the fixed plate of the upper core clamping piece 1.

[0094] The lower end pressing blocks 7 are provided in plurality, each lower end pressing block 7 comprises a pressing block body and a rib plate 8, wherein the top of the pressing block body is provided with a clamping groove, the clamping groove is clamped and matched with the bottom of the low-voltage winding insulation cylinder and the high-voltage winding insulation cylinder 11, and the rib plate 8 is fixedly arranged on the body through bolts, and the rib plate 8 is fixedly connected with the fixed plate of the lower core clamping piece 2. The upper end pressing blocks 6 and the lower end pressing blocks 7 can improve the strength of the whole transformer three-phase cylinder, and these structural improvement measures can help to reduce the vibration or deformation problems that the transformer may encounter in use, and enhance the durability and safety of the equipment.

[0095] The bottom of the low-voltage winding insulation cylinder and the high-voltage winding insulation cylinder 11 is provided with an insulation baffle 5; the top of the lower end pressing block 7 is provided with a clamping groove matched with the insulation baffle 5, and the lower end pressing block 7 is clamped and matched with the insulation baffle 5.

[0096] The top of the low-voltage winding insulation cylinder and the high-voltage winding insulation cylinder 11 is provided with an insulation cylinder upper end baffle 35; the bottom of the upper end pressing block 6 is provided with a clamping groove matched with the insulation cylinder upper end baffle 35, and the upper end pressing block 6 is clamped and matched with the insulation cylinder upper end baffle 35. The problem of overheating of the upper end of the winding pouring cylinder is effectively solved, and the speed of air flowing through the upper end can be improved to enhance the heat dissipation efficiency. When the air flow rate is increased, the heat generated at the upper end of the winding pouring cylinder can be removed more quickly, just like turbulent water flow can remove floating objects more quickly. In this way, the overheating of the upper end can be significantly improved, ensuring stable operation of the equipment, reducing the risk of failure caused by overheating, and prolonging the service life of the equipment.

[0097] The strong wind cold-dry type transformer winding pouring structure further comprises an upper partial-flow baffle 3, one end of the upper partial-flow baffle 3 is fixedly arranged in the interior of the transformer tank 19 through a baffle fixing piece 14, the other end of the upper partial-flow baffle 3 abuts against the fixed plate side wall of the iron core upper clamping piece 1, and the upper partial-flow baffle 3 is located above the lower baffle 4; a plurality of air outlets 20 comprise upper air outlets and lower air outlets, the upper air outlets and the lower air outlets are symmetrically arranged above and below the upper partial-flow baffle 3, and the bottom height of the lower air outlet 21 is higher than the top height of the transformer three-phase cylinder.

[0098] The path of the cooling air when the transformer tank 19 is cooling is as follows: the first air path is discharged from the tank through the gap between the high-voltage outer insulation cylinder 10 and the high-voltage winding epoxy pouring cylinder 13; the second air path is to take away the temperature generated by the operation of the high-voltage winding through the high-voltage winding epoxy resin air duct 26; the third air path is discharged from the tank through the gap between the high-voltage winding epoxy pouring cylinder 13 and the low-voltage winding epoxy pouring cylinder 12; the fourth air path is discharged from the tank through the gap between the inner side of the low-voltage winding epoxy pouring cylinder 12 and the outer surface of the core 9, the gap between the low-voltage winding insulation cylinder, the high-voltage winding insulation cylinder 11 and the high-voltage winding epoxy pouring cylinder 13, and the gap between the low-voltage winding epoxy pouring cylinder 12 and the low-voltage winding insulation cylinder and the high-voltage winding insulation cylinder 11. The design takes into account the low heat dissipation efficiency of the wind power transformer itself, and takes the measure of increasing the air extractor. This measure can improve the air speed and air utilization rate, effectively reduce the temperature rise of the core 9 and the winding, and improve the overall heat dissipation effect. At the same time, by designing the insulation baffle 5, a sealed space is formed, the air utilization rate is improved, and the temperature rise of the core 9 and the winding is further reduced. This measure helps to optimize the heat dissipation structure and improve the working efficiency and stability of the transformer; in addition, the upper part flow baffle 3 and the lower baffle 4 and the insulation baffle 5 are introduced. The traditional dry-type transformer tank 19 has the characteristics of chaotic, slow and mutual interference of air flow. These designs improve the flow direction of the air in the tank (see Figure 14 ), so that the air forms a closed loop to improve the air utilization rate and continuously and effectively reduce the temperature.

[0099] The above is only a few embodiments of the present application, and does not limit the present application in any form. Although the preferred embodiments are disclosed as above, they are not intended to limit the present application. Any skilled person in the art can make some changes or modifications to the disclosed technical content without departing from the scope of the technical solution of the present application, which are equivalent to equivalent embodiments and belong to the scope of the technical solution.

Claims

1. A strong wind cooling dry type transformer winding filling structure, characterized in that, The transformer box (19), the transformer three-phase cylinder, the core (9), the core upper clamp (1), the core lower clamp (2), the lower baffle (4) and the heat pipe heat dissipation assembly, The transformer three-phase cylinder is provided with a plurality of transformer three-phase cylinders, and each transformer three-phase cylinder is arranged around the core (9); The core (9) is arranged in the transformer box (19) through the core upper clamp (1) and the core lower clamp (2); The lower baffle (4) is fixedly arranged in the transformer box (19), the lower baffle (4) divides the transformer box (19) into an upper air outlet part and a lower air supply part, the lower air supply part is provided with an air inlet (23), and the lower baffle (4) is sleeved on the outer wall of the transformer three-phase cylinder; The upper air outlet part of the transformer box (19) is provided with a plurality of air outlets (20); The high-voltage winding epoxy pouring cylinder (13) of the transformer three-phase cylinder is provided with a plurality of ventilation channels in the axial direction; The heat pipe heat dissipation assembly is arranged at the top of the low-voltage winding epoxy pouring cylinder (12) and the high-voltage winding epoxy pouring cylinder (13) of the transformer three-phase cylinder; The heat pipe heat dissipation assembly comprises a heat pipe (28), a heat pipe fin and a heat dissipation rib, the heat pipe (28) comprises a heat absorption section and a heat dissipation section; the heat pipe fin is arranged on the heat dissipation section of the heat pipe (28), the heat pipe fin comprises a plurality of blades, the blades are arranged on the heat pipe fin at intervals; the heat dissipation rib is arranged on the heat absorption section of the heat pipe (28) at an angle, and the other end of the heat dissipation rib extends into the epoxy resin pouring glue of the low-voltage winding epoxy pouring cylinder (12) or the high-voltage winding epoxy pouring cylinder (13); The outer wall and the inner wall of the high-voltage winding epoxy pouring cylinder (13) are both provided with first protrusions at intervals in the circumferential direction, the first protrusions are arranged along the height direction of the high-voltage winding epoxy pouring cylinder (13), and every two adjacent first protrusions form a first ventilation groove; the inner wall and the outer wall of the low-voltage winding epoxy pouring cylinder (12) are both provided with a plurality of second protrusions at intervals in the circumferential direction, the second protrusions are arranged along the height direction of the low-voltage winding epoxy pouring cylinder (12), and every two adjacent second protrusions form a second ventilation groove.

2. The strong wind-cooled dry-type transformer winding potting structure according to claim 1, characterized in that, The core upper clamp (1) comprises a fixed plate and a first connecting bolt (17), the fixed plate is provided with two fixed plates, and the two fixed plates are arranged in parallel, and the two ends of the fixed plate are fixedly arranged in the interior of the transformer box (19); the two fixed plates are connected through the first connecting bolt (17), and when the core (9) is installed, the two fixed plates of the core upper clamp (1) are fixed to the upper part of the core (9) through the first connecting bolt (17). The lower iron core clamping piece (2) is identical in structure to the upper iron core clamping piece (1), and comprises fixing plates and second connecting bolts (18). The fixing plates are provided in two, and the two fixing plates are arranged in parallel. The two ends of the fixing plates are fixedly arranged in the interior of the transformer box (19). The two fixing plates are connected by the second connecting bolts (18). When the iron core (9) is installed, the two fixing plates of the lower iron core clamping piece (2) are fixed to the lower part of the iron core (9) by the second connecting bolts (18).

3. The strong air-cooled dry transformer winding potting structure according to claim 2, characterized in that, The lower wind deflector (4) is provided with a hole matched with the transformer three-phase cylinder. The transformer three-phase cylinder comprises, from the inside to the outside, a low-voltage winding epoxy pouring cylinder (12), a low-voltage winding insulation cylinder, a high-voltage winding insulation cylinder (11), a high-voltage winding epoxy pouring cylinder (13), and a high-voltage outer insulation cylinder (10). The lower part of the high-voltage outer insulation cylinder (10) is fixedly connected with the inner wall of the hole of the lower wind deflector (4). A plurality of through ventilation channels are arranged in the high-voltage winding epoxy pouring cylinder (13) in a spaced manner. The ventilation channels are arranged along the height direction of the high-voltage winding epoxy pouring cylinder (13). The cross-sectional shape of the second protrusion and the first protrusion is rectangular, sawtooth-shaped, trapezoidal, semicircular, or parabolic.

4. The strong air-cooled dry transformer winding potting structure according to claim 3, comprising the features of, The upper end pressing block (6) is provided in a plurality of, and each upper end pressing block (6) comprises a pressing block body and a rib plate (8). The bottom of the pressing block body is provided with a clamping groove. The pressing block body is clamped and matched with the top of the low-voltage winding insulation cylinder or the high-voltage winding insulation cylinder (11) through the clamping groove. The rib plate (8) is fixedly arranged on the pressing block body by bolts, and the rib plate (8) is fixedly connected with the fixing plate of the upper iron core clamping piece (1). The lower end pressing block (7) is provided in a plurality of, and each lower end pressing block (7) comprises a pressing block body and a rib plate (8). The top of the pressing block body is provided with a clamping groove. The pressing block body is clamped and matched with the top of the low-voltage winding insulation cylinder or the high-voltage winding insulation cylinder (11) through the clamping groove. The rib plate (8) is fixedly arranged on the body by bolts, and the rib plate (8) is fixedly connected with the fixing plate of the lower iron core clamping piece (2).

5. The strong air-cooled dry transformer winding potting structure according to claim 4, characterized in that, The top of the low-voltage winding insulation cylinder and the high-voltage winding insulation cylinder (11) is provided with an insulation cylinder upper end wind deflector (35). The bottom of the upper end pressing block (6) is provided with a clamping groove matched with the insulation cylinder upper end wind deflector (35). The upper end pressing block (6) is clamped and matched with the insulation cylinder upper end wind deflector (35).

6. The strong wind-cooled dry-type transformer winding potting structure according to claim 4, characterized in that, The bottom of the low-voltage winding insulation cylinder and the high-voltage winding insulation cylinder (11) is provided with an insulation wind deflector (5). The top of the lower end pressing block (7) is provided with a clamping groove matched with the insulation wind deflector (5). The lower end pressing block is clamped and matched with the insulation wind deflector (5).

7. The strong wind-cooled dry-type transformer winding potting structure according to claim 3, characterized in that, The upper part flow baffle (3) is fixedly arranged at one end in the transformer box (19), and the other end of the upper part flow baffle (3) is in abutment with the fixed plate side wall of the upper core clamp (1), and the upper part flow baffle (3) is located above the lower baffle (4); the bottom of the air outlet (20) is higher than the top of the transformer three-phase cylinder.

8. The strong wind-cooled dry-type transformer winding potting structure according to claim 3, characterized in that, When the transformer box (19) is cooled, the path of the cooling air is as follows: the first air path is discharged from the box through the gap between the high-voltage outer insulation cylinder (10) and the high-voltage winding epoxy pouring cylinder (13); the second air path is used to take away the temperature generated by the work of the high-voltage winding through the high-voltage winding epoxy resin air duct (26); the third air path is discharged from the box through the gap between the high-voltage winding epoxy pouring cylinder (13) and the low-voltage winding epoxy pouring cylinder (12); the fourth air path is discharged from the box through the gap between the inner side of the low-voltage winding epoxy pouring cylinder (12) and the outer surface of the core (9), the gap between the low-voltage winding insulation cylinder, the high-voltage winding insulation cylinder (11) and the high-voltage winding epoxy pouring cylinder (13), and the gap between the low-voltage winding epoxy pouring cylinder (12) and the low-voltage winding insulation cylinder and the high-voltage winding insulation cylinder (11).

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