Oil-immersed transformer

Abstract

The utility model relates to the technical field of transformers, in particular to an oil-immersed transformer. The oil-immersed transformer comprises an oil tank, the oil tank is sequentially connected with an oil suction pipe, an oil pump, a cooling device and an oil outlet pipe, the cooling device comprises a cooling container, cooling water is arranged in the cooling container, a heat dissipation box is arranged in the cooling container, and an oil inlet hole and an oil outlet hole are formed in the heat dissipation box. The oil suction pipe and the oil outlet pipe are respectively connected. The oil pump pumps heated insulating oil into the heat dissipation box through the oil suction pipe, cooling water in the cooling container absorbs heat of the insulating oil, the heat dissipation area of the heat dissipation box is larger, the heat dissipation efficiency is higher, the cooled insulating oil returns into the oil tank through the oil outlet pipe, and rapid cooling of the transformer is achieved. Therefore, the problem that an oil-immersed transformer heat dissipation device is low in heat dissipation rate is solved.

Description

Technical Field

[0001] The utility model relates to the technical field of transformers, in particular to an oil-immersed transformer. Background Art

[0002] A transformer is a relatively static electrical device consisting of two or more windings wound on the same iron core, which are interconnected by alternating magnetic flux. In order to economically transmit, reasonably distribute and safely use the electric energy generated by power plants, power transformers are used.

[0003] At present, the most commonly used transformer is the oil-immersed transformer, also known as the wet transformer. The oil-immersed transformer is a new type of high-performance transformer with a more reasonable structure and better performance. It uses oil as the main insulation means of the transformer and relies on oil as a cooling medium to convert electrical energy from one voltage level to another. It is an electrical equipment used to adjust the power supply voltage, load balancing, power conversion, isolation, voltage stabilization, etc. The oil-immersed transformer will produce copper loss and iron loss during operation. These losses will eventually be converted into heat energy, which will cause the iron core and winding of the transformer to heat up, and the temperature of the insulating oil in the transformer box will also rise. After the temperature rises, it is difficult to cool down in time, so that the transformer winding is at a high temperature level for a long time, the working state is extremely unstable, and the coil life will be greatly shortened, thus affecting the normal operation of the transformer. The existing oil-immersed transformer heat dissipation method is fin heat dissipation, which increases the contact area for heat dissipation by setting fan-shaped blades on both sides, but its heat dissipation capacity is limited, and the noise is large and the cost is high.

[0004] In order to solve the above problems, a Chinese utility model patent with authorization announcement number CN206774355U and authorization announcement date of December 19, 2017 discloses a silicone oil wet transformer box structure, which includes a base, a water tank, an oil outlet pipe, a metal oil pipe, an oil pump, an inner box, and an outer box. The outer box is fixedly mounted on the base, the bottom surface of the inner box is welded and fixed in the outer box, the inner cavity of the inner box is filled with silicone oil, the outer cavity formed by the inner box and the outer box is filled with diesel, the water tank is fixed on the base, the water tank is filled with cooling water, the outer box is connected to the oil outlet pipe, the oil outlet pipe is connected to the metal oil pipe, the metal oil pipe is located in the water tank, and the metal oil pipe is S-shaped, the metal oil pipe is connected to the oil pump, and is connected back to the outer box. The diesel in the outer box is pumped out by the oil pump and flows through the metal oil pipe. It is cooled by the cooling water in the water tank and finally returns to the outer cavity to realize circulation. The temperature of the diesel is reduced during the continuous circulation. The transformer winding is cooled by heat conduction through the three media of silicone oil, diesel and cooling water, thus realizing the heat dissipation of the transformer.

[0005] The silicone oil wet transformer box structure provided by the above utility model reduces the temperature of the insulating oil (silicone oil) in the transformer, effectively alleviates the problem of excessive temperature rise of the transformer winding, and realizes the heat dissipation of the transformer. However, it uses an S-shaped metal oil pipe to cool the insulating oil through a cooling water tank. The contact area between the metal oil pipe and the cooling water is limited, and its heat dissipation rate is slow. In addition, diesel is used for circulating cooling between the transformer oil tank and the outer box. Once the diesel leaks and overflows, it is very likely to explode and damage the transformer. The safety hazard is relatively high. Long-term use of diesel for cooling will also cause corrosion of the outer wall of the oil tank and the cooling device, affecting the performance and life of the transformer. Utility Model Content

[0006] The utility model aims to provide an oil-immersed transformer to solve the problem of slow heat dissipation rate of the heat dissipation device of the oil-immersed transformer in the prior art.

[0007] In order to achieve the above purpose, the oil-immersed transformer of the utility model adopts the following technical solutions:

[0008] An oil-immersed transformer comprises an oil tank, which is sequentially connected to an oil suction pipe, an oil pump, a cooling device, and an oil outlet pipe. The cooling device comprises a cooling container, in which cooling water is arranged. A heat sink is arranged in the cooling container, and an oil inlet hole and an oil outlet hole are arranged on the heat sink, which are respectively used to connect the oil suction pipe and the oil outlet pipe.

[0009] Beneficial effects: The oil-immersed transformer of the utility model is an improved invention. Specifically, a heat sink is arranged in the cooling container, and an oil inlet hole and an oil outlet hole are arranged on the heat sink, and the oil suction pipe and the oil outlet pipe are connected respectively. The oil pump draws the heated insulating oil into the heat sink through the oil suction pipe, and the cooling water in the cooling container will absorb the heat of the insulating oil. The heat sink has a larger heat dissipation area and a higher heat dissipation efficiency. The cooled insulating oil returns to the inside of the oil tank through the oil outlet pipe. The oil pump continues to run, continuously extracting high-temperature insulating oil and feeding low-temperature insulating oil. Through the circulation of insulating oil, the heat inside the oil tank is taken out, and the transformer is quickly cooled. This solves the problem of slow heat dissipation rate of the heat dissipation device of the oil-immersed transformer.

[0010] Furthermore, the oil inlet and the oil outlet are respectively arranged at the top and the bottom of the heat dissipation box.

[0011] Furthermore, the heat dissipation box is a flat box, and the flat box is in a rectangular parallelepiped shape.

[0012] Furthermore, the cooling container is adapted to the shape of the heat sink.

[0013] Furthermore, the heat dissipation box is arranged at the center of the cooling container, and the outer side wall of the heat dissipation box is spaced apart from the cooling container.

[0014] Furthermore, the cooling container is provided with a water inlet hole.

[0015] Furthermore, a support frame is connected to the upper end of the oil tank, and an oil pillow is connected to the support frame.

[0016] Furthermore, an air bag is provided on the inner wall of the oil pillow, an outlet of the air bag is connected to a breathing tube, a tail end of the breathing tube is connected to a respirator, and the interior of the respirator is filled with a desiccant.

[0017] Furthermore, the inner bottom wall of the oil tank is connected to a transformer body, the transformer body includes an iron core and a winding assembly, the iron core includes a horizontal iron core and a vertical iron core, the horizontal iron core and the vertical iron core form a sun shape, and the outside of the horizontal iron core and the vertical iron core are both sleeved with winding assemblies.

[0018] Furthermore, the winding assembly includes a first insulating layer, a primary winding, a second insulating layer, a secondary winding and a third insulating layer, the first insulating layer is sleeved on the outside of the iron core, the primary winding is sleeved on the outside of the first insulating layer, the second insulating layer is sleeved on the outside of the primary winding, the secondary winding is sleeved on the outside of the second insulating layer, and the third insulating layer is sleeved on the outside of the secondary winding. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a schematic diagram of the structure of the oil-immersed transformer of the utility model;

[0020] Figure 2 This is a schematic diagram of the cross-sectional structure of the oil-immersed transformer of the utility model;

[0021] Figure 3 This is a schematic diagram of the cross-sectional structure of the oil-immersed transformer body of the utility model;

[0022] Figure 4 It is a schematic diagram of the enlarged structure of position A of the oil-immersed transformer body of the utility model.

[0023] In the figure: 1. oil suction pipe; 2. oil pump; 3. oil outlet pipe; 4. cooling device; 5. oil tank; 6. insulating oil; 7. support frame; 8. oil pillow; 9. relay; 10. transformer body; 11. breathing tube; 12. respirator; 13. through hole; 14. water inlet hole; 15. high-voltage insulating sleeve; 16. low-voltage insulating sleeve; 17. explosion-proof door; 18. support foot; 22. oil outlet hole; 23. iron core; 24. winding assembly; 101. tail end of oil suction pipe; 211. horizontal iron core; 212. vertical iron core; 221. first insulating layer; 222. primary winding; 223. second insulating layer; 224. secondary winding; 225. third insulating layer; 301. tail end of oil outlet pipe; 302. starting point of oil outlet pipe; 401. cooling container; 402. heat sink. DETAILED DESCRIPTION

[0024] The features and performance of the present invention are further described in detail below in conjunction with the embodiments.

[0025] A silicone oil wet transformer box structure disclosed in the prior art uses an S-shaped metal oil pipe to cool the diesel through a cooling water tank, and then cools the insulating oil through heat conduction. Since the contact area between the S-shaped metal oil pipe and the cooling water is limited, its heat dissipation rate is slow; and the diesel is used for circulating cooling between the transformer oil tank and the outer box. Once the diesel leaks and overflows, it is very easy to explode and damage the transformer, which has a high safety hazard. Long-term use of diesel for cooling will also cause corrosion of the outer wall of the oil tank and the cooling device, affecting the performance and life of the transformer. In response to the above problems, the utility model proposes an improved solution. The core concept of the solution is to set a heat dissipation box in the cooling container. The heat dissipation box is a flat box, which can make its heat dissipation area larger and the heat dissipation efficiency higher. The heated insulating oil is directly pumped into the heat dissipation box through an oil pump. The cooling water in the cooling container will directly absorb the heat of the insulating oil, and its heat dissipation effect is better.

[0026] Based on the above invention concept, Figure 1 and Figure 2 As shown, an oil-immersed transformer of the utility model includes an oil tank 5, which is sequentially connected to an oil suction pipe 1, an oil pump 2, a cooling device 4, and an oil outlet pipe 3. The cooling device 4 includes a cooling container 401, in which cooling water is provided, and a heat sink 402 is provided in the cooling container 401. The heat sink 402 is provided with an oil inlet hole and an oil outlet hole 22, which are respectively used to connect the oil suction pipe 1 and the oil outlet pipe 3.

[0027] Among the above components, the cooling device 4 includes a cooling container 401, and the cooling container 401 is filled with cooling water. Figure 1 and Figure 2In the embodiment shown, the cooling container 401 is arranged on the back of the oil tank 5 and is fixed by welding. In some other embodiments, the cooling container 401 can be arranged on the side or bottom of the oil tank 5 according to the specific size of the oil tank 5. The fixing method can also be flexibly selected, such as bolt connection, adhesive connection, etc. In order to facilitate the cooling container 401 to be fixed on the oil tank 5, the cooling container 401 is preferably a box structure that matches the structure of the oil tank 5. The box is preferably in a rectangular shape, and for the sake of beauty and no bumping, its four corners are set to arc shapes. In some other embodiments, the box can also be set to a cube or other quadrangular prism shapes, or no rounded corners are set. Through holes 13 are respectively provided at the top and bottom center positions of the cooling container 401, for the oil suction pipe 1 and the oil outlet pipe 3 to pass through respectively. A water inlet 14 is provided on the front of the cooling container 401. The water inlet 14 is a round hole, which can facilitate the access of the external cooling water pipe. In some other embodiments, the position of the water inlet 14 is not particularly limited, and the shape is not fixed. It can be convenient to access the cooling water pipe.

[0028] A heat sink 402 is provided in the cooling container 401. Figure 2 In the embodiment shown, in order to make the heat dissipation area larger, the shape of the heat dissipation box 402 is adapted to the shape of the cooling container 401. The shape of the heat dissipation box 402 is also preferably a rectangular parallelepiped, and the four corners are also arc-shaped. In order to quickly cool down the insulating oil 6 after heating, the heat dissipation box 402 is set as a flat box, which can make its heat dissipation rate faster and the heat dissipation area larger. In some other embodiments, the shape of the heat dissipation box 402 is not particularly limited, and other shapes that match the cooling container 402 can be selected. Of course, it is also possible not to match. In order to achieve a better cooling effect and take into account the balance of the entire cooling device 4, the heat dissipation box 402 is arranged in the center of the cooling container 401, and the outer wall of the heat dissipation box 402 is arranged at intervals from the cooling container 401, which can ensure that the cooling water is completely immersed around the heat dissipation box 402. In some other embodiments, the heat dissipation box 402 may not be arranged in the center of the cooling container 401. Considering the stable operation of the entire cooling device 4, the bottom of the heat sink 402 is fixed on the inner bottom surface of the cooling container 401, which can ensure that the heat sink 402 does not float in the cooling water, and the oil suction pipe 1 and the oil outlet pipe 3 will not be bent due to floating. Since the outside of the heat sink 402 is soaked in cooling water for a long time, and the inside is soaked in insulating oil 6 for a long time, and considering its thermal conductivity and corrosion resistance, the material of the heat sink 402 is preferably a metal thermal conductive material. In some other implementations, titanium alloy, stainless steel, etc. can also be used. The top and bottom of the heat sink 402 are respectively provided with an oil inlet hole and an oil outlet hole 22, which are respectively connected to the tail end 101 of the oil suction pipe and the starting point 302 of the oil outlet pipe. Figure 2In the embodiment shown, the oil inlet and outlet holes 22 are respectively located at the middle position of the top and bottom of the heat dissipation box 402, which can make the insulating oil 6 cool for a longer time and achieve a better heat dissipation effect. The oil inlet and outlet holes 22 are preferably set as internal thread holes and sealed with sealing gaskets, which can be threaded with the oil suction pipe 1 and the oil outlet pipe 3. Under strong oil flow, the oil suction pipe 1 and the oil outlet pipe 3 will not be washed off, and the insulating oil 6 will not leak into the cooling container 401. In some other embodiments, the internal thread holes may not be provided, and the oil suction pipe 1 and the oil outlet pipe 3 can be welded to the oil inlet and outlet holes 22 respectively, or directly inserted into the oil inlet and outlet holes 22. The oil inlet and outlet holes 22 are located on the same straight line with the through holes 13 at the top and bottom of the oil tank 5, which can facilitate the smooth passage of the oil suction pipe 1 and the oil outlet pipe 3. In some other embodiments, the oil inlet and outlet holes 22 are also not located on the same straight line with the through holes 13 at the top and bottom of the oil tank 5.

[0029] In such Figure 1 and Figure 2 In the illustrated embodiment, the oil pump 2 is arranged at the lower end of the front side of the oil tank 5, which can facilitate the connection of the oil suction pipe 1 with the oil tank 5 and the cooling device 4. In some other implementations, the position of the oil pump 2 is not specifically limited. The starting point of the oil suction pipe extends to the lower end of the oil tank 1, connected to the oil pump 5, passes through the bottom through hole of the cooling container 401, and the tail end of the oil suction pipe is connected to the oil inlet hole at the bottom of the heat sink 402, so that the heated insulating oil 6 can be smoothly pumped into the heat sink 402. The oil outlet pipe 3 is arranged at the upper end of the oil tank 5, and the shape of the oil outlet pipe 3 is U-shaped. The starting point 302 of the oil outlet pipe is connected to the oil outlet hole 22 on the top surface of the heat sink 402, and passes through the top through hole 13 of the cooling container 401. The tail end 301 of the oil outlet pipe extends to the inside of the oil tank 5, so that the cooled insulating oil 6 can be smoothly delivered to the inside of the oil tank 5. In some other implementations, the shape of the oil outlet pipe 3 can also be L-shaped, without special restrictions, as long as the cooled insulating oil 6 can be smoothly delivered to the inside of the oil tank 5.

[0030] In such Figure 1 and Figure 2In the illustrated embodiment, a support frame 7 is connected to the upper end of the fuel tank 5, an oil conservator 8 is connected to the support frame 7, the oil conservator 8 is connected to the inside of the fuel tank 5 through an oil pipe, the middle of the oil pipe is connected in series with a relay 9, the input end of the relay 9 is electrically connected to an external power supply, the input end of the oil pump 2 is electrically connected to the output end of the relay 9, the input end of the transformer body 10 is electrically connected to the output end of the relay 9. When a fault occurs inside the transformer, the relay 9 will close the trip circuit. When no fault occurs, the fault signal circuit is closed, thus playing a protective role for the transformer. An air bag is provided on the inner wall of the oil conservator 8, the air bag outlet is connected to a breather pipe 11, the tail end of the breather pipe 11 is connected to a breather 12, and the inside of the breather 12 is filled with a desiccant, and the desiccant is silica gel. When the oil temperature rises and causes the volume of the insulating oil 6 to increase, the air inside the air bag is squeezed out, and the air is discharged through the breather 12. When the oil quantity decreases or the temperature drops and causes the volume of the insulating oil 6 to decrease, the air bag expands, and the silica gel absorbs the moisture of the air entering the air bag, avoiding water accumulation in the air bag and moisture absorption of the transformer. In some other embodiments, the desiccant can also be calcium chloride, cobalt chloride, etc.

[0031] In the embodiments as Figure 2 and Figure 3 shown, the transformer body 10 is connected to the inner bottom wall of the fuel tank 5, the inside of the fuel tank 5 is filled with insulating oil 6, the transformer body 10 is immersed in the insulating oil 6, the transformer body 10 includes an iron core 23 and a winding assembly 24, the iron core includes a horizontal iron core 211 and a vertical iron core 212, the horizontal iron core 211 and the vertical iron core 212 are welded together to form a shape like the Chinese character 'Ri' (day). The 'Ri'-shaped iron core has a small volume, high efficiency, and is not prone to electromagnetic interference. The outside of both the horizontal iron core 211 and the vertical iron core 212 is sleeved with a winding assembly 24.

[0032] In the embodiments as Figure 3 and Figure 4 shown, the winding assembly 24 includes a first insulating layer 221, a primary winding 222, a second insulating layer 223, a secondary winding 224, and a third insulating layer 225. The first insulating layer 221 is sleeved on the outside of the vertical iron core 212, the primary winding 222 is sleeved on the outside of the first insulating layer 221, the second insulating layer 223 is sleeved on the outside of the primary winding 222, the secondary winding 224 is sleeved on the outside of the second insulating layer 223, and the third insulating layer 225 is sleeved on the outside of the secondary winding 224. The input ends of the primary winding 222 are all electrically connected to the output end of the relay 9. High-voltage alternating current generates a changing magnetic field through the primary winding 222, and the changing magnetic field passes through the secondary winding 224, and the secondary winding 224 generates an electromotive force.

[0033] In the embodiments as Figure 1 and Figure 2In the illustrated embodiment, the front side of the upper end of the oil tank 5 is fixedly connected with uniformly distributed high-voltage insulating sleeves 15, the rear side of the upper end of the oil tank 5 is fixedly connected with uniformly distributed low-voltage insulating sleeves 16, an explosion-proof door 17 is provided at the upper end of the oil tank 5, and supporting feet 18 are fixedly connected to the left and right sides of the lower end of the oil tank 5 respectively. If a major fault occurs, the pressure inside the oil tank 5 reaches a certain level and will rupture, and the explosion-proof door 17 can quickly release the pressure to avoid an explosion.

[0034] When the oil-immersed transformer is working, high-voltage alternating current generates a changing magnetic field through the primary winding 222, and the changing magnetic field passes through the secondary winding 224, and the secondary winding 224 generates an electromotive force. During operation, copper loss and iron loss will be generated, and the iron core 23 and the winding assembly 24 of the transformer will heat up, generating a large amount of heat. The temperature of the insulating oil 6 inside the oil tank 1 will increase, and the oil pump 2 will pump the heated insulating oil 6 into the heat sink 402. The cooling water in the cooling container 401 absorbs the heat of the insulating oil 6. The cooled insulating oil 6 returns to the inside of the oil tank 5 from the upper end of the oil tank 5. The oil pump 2 continues to operate, continuously pumping out high-temperature insulating oil 6 and sending in low-temperature insulating oil 6. Through the circulation of the insulating oil 6, the heat inside the oil tank 1 is taken out, and the transformer is cooled. When the temperature of the insulating oil 6 increases, the volume of the insulating oil 6 increases, squeezing out the air in the airbag, and the air is discharged through the respirator 12. The interior of the respirator 12 is filled with silica gel. When the amount of oil decreases or the temperature drops, causing the volume of the insulating oil 6 to decrease, the airbag becomes larger, and the silica gel absorbs the moisture of the air that will enter the airbag to avoid water accumulation in the airbag. When there is an internal fault in the oil tank 5, the relay 9 will connect the tripping circuit under the action of the generated gas or oil flow, so that the transformer is cut off from the power grid, thereby protecting the transformer. When a major fault occurs, the pressure inside the oil tank 5 reaches a certain level and it will rupture, and the explosion-proof door 17 quickly releases pressure to avoid the occurrence of an explosion.

Claims

1. An oil-immersed transformer, comprising an oil tank, the oil tank being connected in sequence to an oil suction pipe, an oil pump, a cooling device, and an oil outlet pipe, the cooling device comprising a cooling container, the cooling container being provided with cooling water, characterized in that: A heat dissipation box is provided inside the cooling container, and an oil inlet hole and an oil outlet hole are provided on the heat dissipation box, which are respectively used to connect the oil suction pipe and the oil discharge pipe.

2. The oil-immersed transformer according to claim 1, characterized in that: The oil inlet hole and the oil outlet hole are respectively arranged at the top and bottom of the heat dissipation box.

3. The oil-immersed transformer according to claim 1, characterized in that: The heat dissipation box is a flat box body, and the flat box body is in the shape of a cuboid.

4. The oil-immersed transformer according to claim 1, 2 or 3, characterized in that: The cooling container is adapted to the shape of the heat dissipation box.

5. The oil-immersed transformer according to claim 4, characterized in that: The heat dissipation box is arranged at the center of the cooling container, and the outer side wall of the heat dissipation box is arranged at intervals with the cooling container.

6. The oil-immersed transformer according to claim 5, characterized in that: A water inlet hole is provided on the cooling container.

7. The oil-immersed transformer according to claim 1, characterized in that: A support frame is connected to the upper end of the fuel tank, and an oil conservator is connected to the support frame.

8. The oil-immersed transformer according to claim 7, characterized in that: An air bag is provided on the inner wall of the oil conservator. The outlet of the air bag is connected to a breather pipe, the tail end of the breather pipe is connected to a breather, and the inside of the breather is filled with a desiccant.

9. The oil-immersed transformer according to claim 1, characterized in that: The inner bottom wall of the fuel tank is connected with a transformer body. The transformer body includes an iron core and a winding assembly. The iron core includes a horizontal iron core and a vertical iron core. The horizontal iron core and the vertical iron core enclose a shape like the Chinese character 'Ri' (日), and winding assemblies are sleeved outside both the horizontal iron core and the vertical iron core.

10. The oil-immersed transformer according to claim 9, characterized in that: The winding assembly includes a first insulating layer, a primary winding, a second insulating layer, a secondary winding and a third insulating layer. The first insulating layer is sleeved outside the iron core, the primary winding is sleeved outside the first insulating layer, the second insulating layer is sleeved outside the primary winding, the secondary winding is sleeved outside the second insulating layer, and the third insulating layer is sleeved outside the secondary winding.

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