Distribution transformer with internal electricity taking and heat dissipation structure and assembly method thereof

Abstract

The invention belongs to the technical field of distribution transformers, and particularly relates to a distribution transformer with an internal electricity taking and heat dissipation structure and an assembling method thereof. In order to overcome the defect of heat dissipation of an existing distribution transformer, the invention adopts the following technical scheme that the distribution transformer with the internal electricity taking and heat dissipation structure comprises a transformer iron core, the transformer coil is wound on the transformer iron core; the electricity taking coil is wound on the transformer iron core; and the auxiliary impeller heat dissipation piece is connected with the electricity taking coil and comprises a motor and a rotatable impeller. The distribution transformer with the internal electricity-taking heat dissipation structure has the beneficial effects that when the transformer works, current is generated on the electricity-taking coil to enable the motor to work, the motor drives the impeller to rotate, the impeller rotates to generate wind or stir transformer oil, and auxiliary heat dissipation of the transformer is achieved; and through the arrangement of the electricity taking coil and the auxiliary impeller heat dissipation piece, the normal working temperature of the transformer can be reduced, and the service life of the transformer is prolonged.

Description

Technical Field

[0001] The invention belongs to the technical field of distribution transformers, and in particular relates to a distribution transformer with an internal power taking and heat dissipation structure and an assembly method thereof. Background Art

[0002] Distribution transformers are the final link in the transmission of electricity. They convert high-voltage electricity into low-voltage electricity suitable for end users. The reliability of distribution transformers directly affects the stability and safety of power supply. Since distribution transformers are usually installed near residential and commercial areas, they must be able to operate stably under various environmental conditions, including high temperature, high humidity and high load.

[0003] Distribution transformers will generate losses during operation, mainly from copper losses (resistance losses caused by current passing through the wire) and iron losses (hysteresis and eddy current losses caused by the magnetic core in the alternating magnetic field). These losses are eventually converted into heat energy, causing the internal temperature of the transformer to rise. If the heat cannot be dissipated in time, the insulation material of the transformer will accelerate aging due to overheating, reduce its insulation performance, and increase the risk of failure. Long-term overheating may also cause deformation of the internal structure of the transformer, affecting its normal operation. Therefore, effective heat dissipation is crucial to ensure the long-term stable operation of the transformer.

[0004] Distribution transformers are mainly divided into two types: dry-type transformers and oil-immersed transformers. Dry-type transformers mainly dissipate heat through natural cooling and forced air cooling. The natural cooling method has limited heat dissipation capacity. Therefore, in order to ensure heat dissipation, it is common practice to add fans, which brings several problems: 1. The fan is powered by an external power supply; 2. The power is high, resulting in high energy consumption and obvious noise; 3. It is only started when the temperature is too high, and it cannot reduce the temperature rise during normal operation. Since the heat dissipation performance of oil-immersed transformers is higher than that of dry-type transformers, heat is usually dissipated through heat sinks on the surface. In order to improve the heat dissipation performance, oil-immersed transformers are sometimes equipped with fans or oil pumps. When fans or oil pumps are set, there are similar problems as dry-type transformers using fans. Summary of the invention

[0005] The present invention aims at the deficiencies of heat dissipation of existing distribution transformers and provides a distribution transformer with an internal power supply and heat dissipation structure. The fan directly draws power from the transformer, and there is no need to configure a separate power supply for the fan, thereby reducing the temperature of the transformer during normal operation and reducing the start-up time and frequency of the main fan. The present invention generally provides an assembly method for a distribution transformer with an internal power supply and heat dissipation structure.

[0006] To achieve the above object, the present invention adopts the following technical solution: a distribution transformer with an internal power supply and heat dissipation structure, the distribution transformer with an internal power supply and heat dissipation structure comprises:

[0007] Transformer core;

[0008] A transformer coil, wound on the transformer core;

[0009] A power taking coil, wound on the transformer core;

[0010] The auxiliary impeller heat sink is connected to the power taking coil and comprises a motor and a rotatable impeller.

[0011] The distribution transformer with an internal power-taking and heat-dissipating structure of the present invention has a power-taking coil wound on the transformer core, and an auxiliary impeller heat sink including a motor and a rotatable impeller is provided. When the transformer is working, current is generated on the power-taking coil to make the motor work, and the motor drives the impeller to rotate, generating wind or stirring the transformer oil, thereby realizing auxiliary heat dissipation of the transformer. The provision of the power-taking coil and the auxiliary impeller heat sink can reduce the normal working temperature of the transformer and increase the service life of the transformer. The power of the auxiliary impeller heat sink is very small compared with the loss of the transformer, so it will hardly have any adverse effect on the transformer.

[0012] As an improvement, the transformer core includes a main core and side cores located on both sides of the main core, the vertical surface profile of the main core is larger than that of the side core, the power coil is wound on the main core, a power taking groove is opened on the main core, and the power coil is located in the power taking groove.

[0013] As an improvement, the main iron core includes a plurality of silicon steel sheets of the same size, and power extraction holes are provided on the silicon steel sheets for the power extraction coil to pass through.

[0014] As an improvement, the silicon steel sheets located on both sides of the main iron core are further provided with notches connected to the power extraction holes, and the power extraction holes and the notches form the power extraction grooves.

[0015] As an improvement, the process of determining the relevant parameters of each component in the auxiliary heat dissipation structure is as follows:

[0016] According to the model of the distribution transformer, the auxiliary impeller heat sink is selected, and the total power of all the auxiliary impeller heat sinks does not exceed a certain percentage of the total loss of the transformer;

[0017] The operating voltage V of the auxiliary impeller heat sink s , the number of turns N of the power taking coil, the potential e of each turn of the power taking coil t , the operating frequency f of the distribution transformer, the magnetic flux density B of the transformer core, the maximum cross-sectional area A of the core at the power supply slot t satisfy:

[0018] V s =N*e t (1)

[0019] e t =4.44fBA t (2)

[0020] According to formula (1) and formula (2), we can get:

[0021]

[0022] Among them, the operating voltage V of the auxiliary impeller heat sink s The number and total power are selected within a suitable range, and the operating frequency f of the distribution transformer and the magnetic density B of the transformer core are known;

[0023] According to the working current I and the number n of the auxiliary impeller heat sink, the total current is nI. According to the total current nI, the wire specification of the power coil is selected to obtain the outer diameter D of the wire of the power coil, and then the length c of the iron core at the power slot is obtained:

[0024] c=(N+2)*D(4)

[0025] Wherein, the operating current I of the auxiliary impeller heat sink is selected within a suitable range according to the number and total power thereof;

[0026] The thickness a of the iron core at the power taking slot and the height b of the iron core at the power taking slot are determined according to the following formula:

[0027] A t =a*b(5).

[0028] As an improvement, a mounting column is welded on the transformer core, the auxiliary impeller heat sink is fixed on the mounting column, and a gap is provided between the auxiliary impeller heat sink and the transformer core.

[0029] As an improvement, there are multiple auxiliary impeller heat sinks connected to the same power taking coil and they are connected in parallel.

[0030] As an improvement, there are multiple power extraction coils.

[0031] As an improvement, the distribution transformer is a dry-type transformer, and the auxiliary impeller heat sink is a fan;

[0032] Alternatively, the distribution transformer is an oil-immersed transformer, and the auxiliary impeller heat sink is a pump.

[0033] The assembly method of a distribution transformer with an internal power-taking and heat-dissipating structure is the aforementioned distribution transformer with an internal power-taking and heat-dissipating structure. The assembly method of the distribution transformer with an internal power-taking and heat-dissipating structure comprises:

[0034] Processing power taking holes and notches on the silicon steel sheets of the main iron core of the transformer iron core;

[0035] After stacking the silicon steel sheets to form the main iron core, the power taking coil is wound onto the main iron core;

[0036] Fixing the side cores on both sides of the transformer core to the main core;

[0037] The auxiliary impeller heat sink is installed on the main iron core, and the power taking coil and the auxiliary impeller heat sink are connected.

[0038] The beneficial effects of the distribution transformer with an internal power-taking and heat-dissipating structure of the present invention are as follows: a power-taking coil is wound on the transformer core, and an auxiliary impeller heat sink including a motor and a rotatable impeller is provided. When the transformer is working, current is generated on the power-taking coil to make the motor work, and the motor drives the impeller to rotate. The rotation of the impeller generates wind or stirs the transformer oil, thereby achieving auxiliary heat dissipation of the transformer. The provision of the power-taking coil and the auxiliary impeller heat sink can reduce the normal working temperature of the transformer and increase the service life of the transformer. The power-taking coil and the auxiliary impeller heat sink are usually used as additional devices to assist in heat dissipation, and can also be used as the main heat dissipation means when the operating environment is good. The power of the auxiliary impeller heat sink is very small compared to the loss of the transformer, so it will hardly have any adverse effect on the transformer. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 It is a structural schematic diagram of a distribution transformer with an internal power supply and heat dissipation structure according to Embodiment 1 of the present invention.

[0040] Figure 2 and Figure 3 It is a schematic structural diagram at different angles of the transformer core of the distribution transformer with an internal power supply and heat dissipation structure according to the first embodiment of the present invention.

[0041] Figure 4 yes Figure 3 Sectional view along AA direction.

[0042] Figure 5 It is a structural schematic diagram of the middle silicon steel sheet of the main iron core of the transformer core of the distribution transformer with an internal power supply and heat dissipation structure according to the first embodiment of the present invention.

[0043] Figure 6 It is a structural schematic diagram of silicon steel sheets on both sides of the main iron core of the transformer core of a distribution transformer with an internal power supply and heat dissipation structure according to the first embodiment of the present invention.

[0044] In the figure, 1, transformer core; 11, main core; 111, silicon steel sheet; 112, power-taking hole; 113, notch; 12, side core; 13, power-taking slot;

[0045] 2. Transformer coil;

[0046] 3. Power coil;

[0047] 4. Auxiliary impeller heat sink;

[0048] 5. Install the column;

[0049] a. The thickness of the iron core at the power supply slot; b. The height of the iron core at the power supply slot; c. The length of the iron core at the power supply slot. DETAILED DESCRIPTION

[0050] The technical solutions of the embodiments of the present invention are explained and described below, but the following embodiments are only preferred embodiments of the present invention, not all. Based on the embodiments in the implementation mode, other embodiments obtained by those skilled in the art without creative work are all within the protection scope of the present invention.

[0051] See also Figures 1 to 6 , a distribution transformer with an internal power supply and heat dissipation structure according to an embodiment of the present invention, the distribution transformer with an internal power supply and heat dissipation structure comprises:

[0052] Transformer core;

[0053] A transformer coil, wound on the transformer core;

[0054] A power taking coil, wound on the transformer core;

[0055] The auxiliary impeller heat sink is connected to the power taking coil and comprises a motor and a rotatable impeller.

[0056] The distribution transformer with an internal power-taking and heat-dissipating structure of the present invention has a power-taking coil wound on the transformer core, and an auxiliary impeller heat sink including a motor and a rotatable impeller is provided. When the transformer is working, current is generated on the power-taking coil to make the motor work, and the motor drives the impeller to rotate, generating wind or stirring the transformer oil, thereby realizing auxiliary heat dissipation of the transformer. The provision of the power-taking coil and the auxiliary impeller heat sink can reduce the normal working temperature of the transformer and increase the service life of the transformer. The power of the auxiliary impeller heat sink is very small compared with the loss of the transformer, so it will hardly have any adverse effect on the transformer.

[0057] Embodiment 1

[0058] See also Figures 1 to 6 , a distribution transformer with an internal power supply and heat dissipation structure according to a first embodiment of the present invention, the distribution transformer with an internal power supply and heat dissipation structure comprises:

[0059] Transformer core;

[0060] A transformer coil, wound on the transformer core;

[0061] A power taking coil, wound on the transformer core;

[0062] The auxiliary impeller heat sink is connected to the power taking coil and comprises a motor and a rotatable impeller.

[0063] In this embodiment, the transformer core includes a main core and side cores located on both sides of the main core. The vertical surface profile of the main core is larger than that of the side core. The power coil is wound on the main core. A power taking groove is opened on the main core, and the power coil is located in the power taking groove.

[0064] In this embodiment, the main iron core includes a plurality of silicon steel sheets of the same size, and power extraction holes for the power extraction coil to pass through are provided on the silicon steel sheets.

[0065] In this embodiment, the silicon steel sheets on both sides of the main iron core are also provided with notches connected to the power taking holes, and the power taking holes and the notches form the power taking slots. Since the height or width of the silicon steel sheets of the iron cores on both sides is only slightly smaller than that of the silicon steel sheets of the main iron core, and this size difference is usually smaller than the wire diameter of the power taking coil, a notch needs to be provided to leave space for the installation of the power taking coil.

[0066] In other embodiments, when the height or width of the silicon steel sheets of the two side cores is sufficiently smaller than that of the silicon steel sheets of the main core, only power extraction holes need to be processed on all the silicon steel sheets of the main core without processing notches.

[0067] In this embodiment, the process of determining the relevant parameters of each component in the auxiliary heat dissipation structure is as follows:

[0068] First, the auxiliary impeller heat sink is selected according to the model of the distribution transformer, and the total power of all the auxiliary impeller heat sinks does not exceed a certain percentage of the total loss of the transformer;

[0069] Secondly, the operating voltage V of the auxiliary impeller heat sink s , the number of turns N of the power taking coil, the potential e of each turn of the power taking coil t , the operating frequency f of the distribution transformer, the magnetic flux density B of the transformer core, the maximum cross-sectional area A of the core at the power supply slot t satisfy:

[0070] V s =N*e t (1)

[0071] e t =4.44fBA t (2)

[0072] According to formula (1) and formula (2), we can get:

[0073]

[0074] Among them, the operating voltage V of the auxiliary impeller heat sink s The number and total power are selected within a suitable range, and the operating frequency f of the distribution transformer and the magnetic density B of the transformer core are known;

[0075] Then, according to the working current I and the number n of the auxiliary impeller heat sink, the total current nI is obtained, and the wire specification of the power taking coil is selected according to the total current nI to obtain the outer diameter D of the wire of the power taking coil, and then the length c of the iron core at the power taking slot is obtained:

[0076] c=(N+2)*D(4)

[0077] Wherein, the operating current I of the auxiliary impeller heat sink is selected within a suitable range according to the number and total power thereof;

[0078] Finally, the thickness a of the iron core at the power taking slot and the height b of the iron core at the power taking slot are determined according to the following formula:

[0079] A t =a*b(5).

[0080] In this embodiment, a mounting column is welded on the transformer core, the auxiliary impeller heat sink is fixed on the mounting column, and a gap is provided between the auxiliary impeller heat sink and the transformer core.

[0081] In this embodiment, there is one power taking coil, and there are multiple auxiliary impeller heat sinks connected to the same power taking coil and connected in parallel. Specifically in this embodiment, there are three auxiliary impeller heat sinks, all located above the main iron core.

[0082] In other embodiments, there may be multiple power extraction coils.

[0083] In this embodiment, the distribution transformer is a dry-type transformer, and the auxiliary impeller heat sink is a fan.

[0084] The specific parameters and dimensions of the distribution transformer of this embodiment are further described below.

[0085] There is a dry-type transformer with a capacity of 400kVA. Its total loss is 3780W and the core working magnetic flux density B is 1.43T.

[0086] (1) Based on the total transformer loss of 3780W, the allowable fan loss is 7.56W. If there are three fans, the maximum power of a single fan is 2.52W.

[0087] (2) Select a certain model of AC fan, whose operating voltage V s It is 12V, the power is 2.16W, and its current I is 0.18A.

[0088] (3) The transformer frequency f is 50 Hz. Substitute the magnetic flux density B and f into formula (3):

[0089]

[0090] The following table shows the values ​​of At and N that partially satisfy the relationship:

[0091] combination <![CDATA[At (Cross-sectional area of iron core at the grooving position) / mm 2 > N (Number of turns of power coil) 1 9450 4 2 3150 12 3 1575 24 4 787.5 48

[0092] It can be seen that the smaller the number of turns N is, the larger the area At required for slotting is. In this example, At=1575mm is selected according to the actual situation. 2 , N=24.

[0093] (4) According to the fan operating current I and the number of fans n (where I is 0.18A and n is 3), the total current nI = 0.18*3 = 0.54A is obtained. According to the national standard GB / T 4706.1-2005, the long-term load current allowed for a copper core wire of 1 square millimeter is 8A. Therefore, the wire specification selected in this example is 1mm 2 The copper wire of the power taking coil has an outer diameter D of 1.13 mm. According to the formula c=(N+2)*D, the length c of the iron core at the power taking slot is 29.38 mm.

[0094] (5) After determining At and N, calculate the slot size. To facilitate the core slotting, the slot width is determined based on the primary width of the transformer core (the thickness of the main core). The primary width of the transformer core is 91 mm. The thickness of the core at the power-taking slot is a=91-2*D=88.74 mm, and the height of the core at the power-taking slot is b=1575 / 88.74=17.75 mm.

[0095] The beneficial effects of the distribution transformer with an internal power-taking and heat-dissipating structure of the first embodiment of the present invention are as follows: a power-taking coil is wound on the transformer core, and an auxiliary impeller heat sink including a motor and a rotatable impeller is provided. When the transformer is working, current is generated on the power-taking coil to make the motor work, and the motor drives the impeller to rotate. The rotation of the impeller generates wind or stirs the transformer oil, thereby achieving auxiliary heat dissipation of the transformer. The provision of the power-taking coil and the auxiliary impeller heat sink can reduce the normal working temperature of the transformer and increase the service life of the transformer. The power-taking coil and the auxiliary impeller heat sink are usually used as additional devices to assist in heat dissipation, and can also be used as the main heat dissipation means when the operating environment is good. The power of the auxiliary impeller heat sink is very small compared to the loss of the transformer, so it will hardly have any adverse effect on the transformer.

[0096] Embodiment 2

[0097] In this embodiment, the distribution transformer is an oil-immersed transformer, and the auxiliary impeller heat sink is a pump. Compared with a dry-type transformer, the main feature of an oil-immersed transformer is that a sealed housing is arranged outside the transformer core, and the sealed housing is filled with transformer oil, and the transformer oil immerses the transformer core and the transformer coil.

[0098] The embodiment of the present invention also provides an assembly method of a distribution transformer with an internal power supply and heat dissipation structure. The distribution transformer with an internal power supply and heat dissipation structure is Figures 1 to 6 The distribution transformer with an internal power supply and heat dissipation structure shown in the figure, the assembly method of the distribution transformer with an internal power supply and heat dissipation structure includes:

[0099] Processing power taking holes and notches on the silicon steel sheets of the main iron core of the transformer iron core;

[0100] After stacking the silicon steel sheets to form the main iron core, the power taking coil is wound onto the main iron core;

[0101] Fixing the side cores on both sides of the transformer core to the main core;

[0102] The auxiliary impeller heat sink is installed on the main iron core, and the power taking coil and the auxiliary impeller heat sink are connected.

[0103] A power-taking hole is processed on the silicon steel sheet in the middle of the main iron core, and U-shaped grooves are directly processed on the silicon steel sheets on both sides of the main iron core. The upper part of the U-shaped groove is a notch, and the lower part is a power-taking hole.

[0104] The above is only a specific implementation of the invention, but the protection scope of the invention is not limited thereto. Those skilled in the art should understand that the invention includes but is not limited to the contents described in the above specific implementation. Any modification that does not deviate from the functional and structural principles of the invention will be included in the scope of the claims.

Claims

1. A distribution transformer with an internal power supply and heat dissipation structure, characterized in that: include: Transformer core; A transformer coil, wound on the transformer core; A power taking coil, wound on the transformer core; The auxiliary impeller heat sink is connected to the power taking coil and comprises a motor and a rotatable impeller.

2. The distribution transformer with internal power supply and heat dissipation structure according to claim 1, characterized in that: The transformer core includes a main core and side cores located on both sides of the main core. The vertical surface profile of the main core is larger than that of the side core. The power coil is wound on the main core. A power groove is provided on the main core, and the power coil is located in the power groove.

3. The distribution transformer with internal power supply and heat dissipation structure according to claim 2, characterized in that: The main iron core includes a plurality of silicon steel sheets of the same size, and power taking holes for the power taking coil to pass through are provided on the silicon steel sheets.

4. The distribution transformer with internal power supply and heat dissipation structure according to claim 3, characterized in that: The silicon steel sheets located on both sides of the main iron core are also provided with notches connected to the power taking holes, and the power taking holes and the notches form the power taking grooves.

5. The distribution transformer with internal power supply and heat dissipation structure according to claim 4, characterized in that: The process of determining the relevant parameters of each component in the auxiliary heat dissipation structure is as follows: According to the model of the distribution transformer, the auxiliary impeller heat sink is selected, and the total power of all the auxiliary impeller heat sinks does not exceed a certain percentage of the total loss of the transformer; The operating voltage V of the auxiliary impeller heat sink s , the number of turns N of the power taking coil, the potential e of each turn of the power taking coil t , the operating frequency f of the distribution transformer, the magnetic flux density B of the transformer core, the maximum cross-sectional area A of the core at the power supply slot t satisfy: V s =N*e t (1) And t =4.44fBA t (2) According to formula (1) and formula (2), we can get: Among them, the operating voltage V of the auxiliary impeller heat sink s The number and total power are selected within a suitable range, and the operating frequency f of the distribution transformer and the magnetic density B of the transformer core are known; According to the working current I and the number n of the auxiliary impeller heat sink, the total current is nI. According to the total current nI, the wire specification of the power coil is selected to obtain the outer diameter D of the wire of the power coil, and then the length c of the iron core at the power slot is obtained: c=(N+2)*D (4) Wherein, the operating current I of the auxiliary impeller heat sink is selected within a suitable range according to the number and total power thereof; The thickness a of the iron core at the power taking slot and the height b of the iron core at the power taking slot are determined according to the following formula: A t =a*b(5)。 6. The distribution transformer with internal power supply and heat dissipation structure according to claim 1, characterized in that: A mounting column is welded on the transformer core, the auxiliary impeller heat sink is fixed on the mounting column, and a gap is provided between the auxiliary impeller heat sink and the transformer core.

7. The distribution transformer with internal power supply and heat dissipation structure according to claim 1, characterized in that: There are multiple auxiliary impeller heat sinks connected to the same power taking coil and they are connected in parallel.

8. The distribution transformer with internal power supply and heat dissipation structure according to claim 1, characterized in that: There are multiple power taking coils.

9. The distribution transformer with internal power supply and heat dissipation structure according to claim 1, characterized in that: The distribution transformer is a dry-type transformer, and the auxiliary impeller heat sink is a fan; Alternatively, the distribution transformer is an oil-immersed transformer, and the auxiliary impeller heat sink is a pump.

10. A method for assembling a distribution transformer with an internal power supply and heat dissipation structure, wherein the distribution transformer with an internal power supply and heat dissipation structure is the distribution transformer with an internal power supply and heat dissipation structure according to any one of claims 1 to 9, characterized in that: The assembly method of the distribution transformer with an internal power supply and heat dissipation structure comprises: Processing power taking holes and notches on the silicon steel sheets of the main iron core of the transformer iron core; After stacking the silicon steel sheets to form the main iron core, the power taking coil is wound onto the main iron core; Fixing the side cores on both sides of the transformer core to the main core; The auxiliary impeller heat sink is installed on the main iron core, and the power taking coil and the auxiliary impeller heat sink are connected.

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