Cooling device for natural ester insulating oil power transformer

Abstract

This invention discloses a cooling device for a natural ester insulating oil power transformer. An oil conservator is connected to one side of the top of the outer casing, and the conservator is connected to the outer casing for oil replenishment. Multiple cooling chambers are formed between the outer casing and multiple sets of transformer windings, with each cooling chamber corresponding to one of the windings. Natural ester insulating oil is filled into the cooling chambers, and the oil conservator is connected to each of the cooling chambers. Multiple heat exchangers are connected to the outer side of the outer casing along the layout direction of the cooling chambers. Oil inlet and outlet pipes are connected between the heat exchangers and the cooling chambers, respectively. A refrigeration unit is also connected to the outer sides of the outer casing and adjacent heat exchangers. The medium inlet and outlet of the refrigeration unit are both connected to the heat exchangers. The advantages of this invention compared to existing technologies are: it provides a cooling device for a natural ester insulating oil power transformer that is convenient for zoned use, allows for precise temperature control, and is highly targeted.

Description

Technical Field

[0001] This invention relates to the field of power transformer cooling technology, specifically to a cooling device for a power transformer using natural ester insulating oil. Background Technology

[0002] Natural ester insulating oils (such as plant-based esters and epoxy esters) are gradually replacing traditional mineral oils in power transformers due to their high flash point (>200℃), low toxicity, good oxidation stability and biodegradability.

[0003] The current principle of oil-cooled transformers is to cool the insulating oil of the power transformer. The insulating oil is circulated to the outside of the power transformer by an oil pump and cooled by air or water through a heat exchanger. After cooling, the insulating oil is circulated back to the transformer, thereby reducing the temperature of the power transformer windings and core. However, in current transformer cooling equipment, the insulating oil is mostly used for overall flow heat exchange. When used for transformers with multiple windings, it is impossible to adjust the heat power for different zones. This results in different oil temperatures near different windings, making it impossible to cool the windings in a targeted manner, leading to an uneven heat dissipation phenomenon of "local overheating - local undercooling". Summary of the Invention

[0004] The technical problem to be solved by the present invention is to overcome the above-mentioned technical defects and provide a cooling device for a natural ester insulating oil power transformer that is convenient for zoned use, can be used with precise temperature control, and is highly targeted.

[0005] To solve the above-mentioned technical problems, the technical solution provided by the present invention is as follows: a cooling device for a power transformer with natural ester insulating oil, comprising a transformer body, the transformer body comprising an outer shell and multiple sets of transformer windings installed in the outer shell, the outer shell being filled with natural ester insulating oil, and an oil tank being connected to one side of the top of the outer shell, the oil tank being connected to the outer shell for oil replenishment. Multiple cooling chambers are formed between the outer casing and multiple sets of transformer windings. Each cooling chamber corresponds to one of the multiple sets of transformer windings. Natural ester insulating oil is filled in the cooling chambers, and the oil conservator is connected to each of the multiple cooling chambers. Multiple heat exchangers are connected to the outer side of the outer shell along the layout direction of the cooling chamber. An oil inlet pipe and an oil outlet pipe are respectively connected between the heat exchangers and the cooling chamber. A refrigeration unit is also connected between the outer sides of the outer shell and the adjacent heat exchangers. The medium inlet and medium outlet of the refrigeration unit are both connected to the heat exchangers.

[0006] Preferably, the heat exchanger has multiple sets of cold medium inlets arranged in sequence at the upper part and multiple sets of cold medium outlets arranged in sequence at the lower part. Each of the multiple sets of cold medium inlets and cold medium outlets is connected to a capillary heat exchange tube in a one-to-one correspondence.

[0007] Preferably, the capillary heat exchange tubes are serpentine and staggered between adjacent capillary heat exchange tubes.

[0008] Preferably, the cold medium inlet and cold medium outlet are each provided with three sets, and three sets of capillary heat exchange tubes are connected between the three sets of cold medium inlet and cold medium outlet; The heat exchanger contains three sets of capillary heat exchange tubes, forming an upper primary cooling zone, a middle heat exchange zone, and a lower refrigeration zone.

[0009] Preferably, the middle heat exchange zone is the overlapping area of ​​three sets of capillary heat exchange tubes, the upper primary cooling zone is the area where the first set of capillary heat exchange tubes are arranged, and the lower cooling zone is the area where the third set of capillary heat exchange tubes are arranged.

[0010] Preferably, the heat exchanger is further provided with air-cooled heat dissipation fins on the outside, and two sets of capillary plates for heat exchange are provided between the heat exchanger and the air-cooled heat dissipation fins. The capillary plate is arranged in the middle heat exchange zone, and the capillary plate has through holes to accommodate the passage of capillary heat exchange tubes.

[0011] Preferably, the air-cooled heat dissipation fins are aluminum fins with a fin spacing of 5-8mm.

[0012] The advantages of this invention compared with the prior art are as follows: In this invention, the transformer shell is improved to form multiple independently set heat exchange spaces, and the oil in different spaces is individually temperature controlled. The formation of multiple heat exchange spaces further improves the heat exchange efficiency. The arrangement of multiple sets of capillary heat exchange tubes, together with the capillary orifice plate, gradually reduces the oil temperature, improves the overall heat exchange efficiency, disturbs the fluid flow field, reduces dead zones, and is easy to promote and use. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of the cooling device for a power transformer made of natural ester insulating oil.

[0014] Figure 2 This is a schematic diagram of part of the internal structure of the heat exchanger.

[0015] Figure 3 This is a schematic diagram of the internal structure of a power transformer.

[0016] Figure 4 This is a structural schematic diagram of the heat exchanger's cross-section.

[0017] As shown in the figure: 1. Transformer body; 2. Outer shell; 3. Transformer winding; 4. Natural ester insulating oil; 5. Oil conservator; 6. Cooling chamber; 7. Heat exchanger; 8. Oil inlet pipe; 9. Oil outlet pipe; 10. Refrigeration unit; 11. Cold medium inlet; 12. Cold medium outlet; 13. Capillary heat exchange tube; 14. Upper primary cooling zone; 15. Middle heat exchange zone; 16. Lower refrigeration zone; 17. Air-cooled heat dissipation fins; 18. Capillary plate. Detailed Implementation

[0018] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings. Identical components are indicated by the same reference numerals.

[0019] It should be noted that the terms “front,” “back,” “left,” “right,” “up,” and “down” used in the following description refer to the directions shown in the attached diagram, while the terms “inside” and “outside” refer to the directions toward or away from the geometric center of a specific component, respectively.

[0020] To make the content of this invention easier to understand, the technical solutions in the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings.

[0021] Combined with appendix Figure 1-4 As shown, a cooling device for a power transformer with natural ester insulating oil includes a transformer body 1. The transformer body 1 includes an outer shell 2 and multiple sets of transformer windings 3 installed inside the outer shell 2. The outer shell 2 is filled with natural ester insulating oil 4.

[0022] In this application, an oil reservoir 5 is also connected to the top side of the outer shell 2. The oil reservoir 5 is connected to the outer shell 2 to replenish oil. The oil capacity inside the outer shell 2 is adjusted according to the expansion and contraction of the volume due to different temperatures.

[0023] Multiple cooling chambers 6 are formed between the outer casing 2 and multiple sets of transformer windings 3. Each set of cooling chambers 6 corresponds to one set of transformer windings 3. Natural ester insulating oil 4 is filled into the cooling chambers 6. Oil conservators 5 are connected to the multiple sets of cooling chambers 6 respectively. The temperature is controlled in intervals through the one-to-one correspondence of the cooling chambers 6.

[0024] Multiple heat exchangers 7 are connected to the outer side of the outer casing 2 along the arrangement direction of the cooling chamber 6. An oil inlet pipe 8 and an oil outlet pipe 9 are respectively connected between the heat exchangers 7 and the cooling chamber 6. A refrigeration unit 10 is also connected between the outer sides of the outer casing 2 and the adjacent heat exchangers 7. The medium inlet 11 and the medium outlet 12 of the refrigeration unit 10 are both connected to the heat exchangers 7. The upper part of the heat exchangers 7 is provided with multiple sets of cold medium inlets 11 arranged in sequence, and the lower part is connected with multiple sets of cold medium outlets 12 arranged in sequence. The circulation of cold medium and refrigeration unit 10 is completed through the cooperation of the cold medium inlets 11 and the cold medium outlets 12.

[0025] Multiple sets of cold medium inlets 11 and cold medium outlets 12 are connected one-to-one with capillary heat exchange tubes 13 for heat exchange. The capillary heat exchange tubes 13 are serpentine and are staggered between adjacent capillary heat exchange tubes 13.

[0026] The cold medium inlet 11 and the cold medium outlet 12 are each provided with three sets, and three sets of capillary heat exchange tubes 13 are connected between the three sets of cold medium inlet 11 and cold medium outlet 12. The heat exchanger 7 is equipped with three sets of capillary heat exchange tubes 13 to form an upper primary cooling zone 14, a middle heat exchange zone 15 and a lower refrigeration zone 16, respectively. The middle heat exchange zone 15 is the overlapping area of ​​the three sets of capillary heat exchange tubes 13, the upper primary cooling zone 14 is the area where the first set of capillary heat exchange tubes 13 are arranged, and the lower refrigeration zone 16 is the area where the third set of capillary heat exchange tubes 13 are arranged.

[0027] The heat exchanger 7 is also connected to an air-cooled heat dissipation fin 17 on its outer side. Two sets of capillary plates 18 for heat exchange are connected between the heat exchanger 7 and the air-cooled heat dissipation fin 17. The capillary plates 18 are arranged in the middle heat exchange zone 15. The capillary plates 18 are provided with through holes to accommodate the passage of capillary heat exchange tubes 13. The air-cooled heat dissipation fin 17 is used for air-cooled auxiliary cooling to reduce the energy consumption of equipment cooling.

[0028] The air-cooled heat dissipation fins 17 are made of aluminum, with a fin spacing of 5-8mm.

[0029] In specific implementation of this invention, it is confirmed that the level of natural ester insulating oil 4 in the oil conservator 5 is within the normal range. If it is insufficient, it is replenished through the oil conservator oil replenishment port. The natural ester insulating oil 4 is filled into the outer shell 2 and filled into multiple cooling chambers 6, which are in direct contact with multiple sets of transformer windings 3 to absorb the heat generated by the windings. The heated insulating oil flows out from the cooling chamber 6 and enters the heat exchanger. The refrigerant of the refrigeration unit 10 enters the heat exchanger 7 through the medium inlet 11 and flows through the serpentine and staggered capillary heat exchange tubes 13. The upper primary cooling zone 14, the middle heat exchange zone 15 and the lower cooling zone 16 gradually reduce the temperature of the insulating oil. The aluminum fins of the air-cooled heat dissipation fins 17 on the outside of the heat exchanger 7, with a fin spacing of 5-8mm, accelerate the heat dissipation of the heat exchanger surface through air convection. The heat exchange area is increased by two sets of capillary plates to improve heat dissipation efficiency. When the level of the insulating oil changes due to thermal expansion and contraction, the oil conservator automatically replenishes or drains oil to maintain the oil level stability in the system.

[0030] The contents not described in detail in this specification are existing technologies known to those skilled in the art.

[0031] All standard parts used in this invention can be purchased from the market, and irregular parts can be customized according to the description and drawings. The specific connection methods of each part adopt conventional methods such as bolts, rivets, and welding that are mature in the prior art. The machinery, parts and equipment adopt conventional models in the prior art, and the circuit connection adopts conventional connection methods in the prior art, which will not be described in detail here. The contents not described in detail in this specification belong to the prior art known to those skilled in the art.

[0032] The present invention and its embodiments have been described above. This description is not restrictive, and the accompanying drawings are only one embodiment of the present invention; the actual structure is not limited thereto. In conclusion, if those skilled in the art are inspired by this description and design similar structures and embodiments without departing from the spirit of the invention, such designs should fall within the protection scope of the present invention.

Claims

1. A cooling device for a power transformer using natural ester insulating oil, comprising a transformer body (1), the transformer body (1) including an outer casing (2) and multiple sets of windings (3) installed within the outer casing (2), wherein the outer casing (2) is filled with natural ester insulating oil (4), characterized in that: An oil reservoir (5) is also connected to the top side of the outer shell (2), and the oil reservoir (5) is connected to the outer shell (2) for oil replenishment; Multiple cooling chambers (6) are formed between the outer shell (2) and multiple sets of transformer windings (3). The multiple cooling chambers (6) correspond one-to-one with the multiple sets of transformer windings (3). Natural ester insulating oil (4) is filled in the cooling chambers (6). Oil tanks (5) are connected to the multiple cooling chambers (6) respectively. Multiple heat exchangers (7) are connected to the outer side of the outer shell (2) along the arrangement direction of the cooling chamber (6). An oil inlet pipe (8) and an oil outlet pipe (9) are respectively connected between the heat exchangers (7) and the cooling chamber (6). A refrigeration unit (10) is also connected between the outer sides of the outer shell (2) and the adjacent heat exchangers (7). The medium inlet (11) and the medium outlet (12) of the refrigeration unit (10) are both connected to the heat exchangers (7).

2. The cooling device for a natural ester insulating oil power transformer according to claim 1, characterized in that: The heat exchanger (7) is provided with multiple sets of cold medium inlets (11) arranged in sequence at the top and multiple sets of cold medium outlets (12) arranged in sequence at the bottom. Each of the multiple sets of cold medium inlets (11) and cold medium outlets (12) is connected to a capillary heat exchange tube (13).

3. The cooling device for a natural ester insulating oil power transformer according to claim 2, characterized in that: The capillary heat exchange tube (13) is serpentine and is staggered between adjacent capillary heat exchange tubes (13).

4. A cooling device for a natural ester insulating oil power transformer according to claim 2 or 3, characterized in that: The cold medium inlet (11) and cold medium outlet (12) are each provided with three sets, and three sets of capillary heat exchange tubes (13) are connected between the three sets of cold medium inlet (11) and cold medium outlet (12). The heat exchanger (7) is equipped with three sets of capillary heat exchange tubes (13) to form an upper primary cooling zone (14), a middle heat exchange zone (15) and a lower refrigeration zone (16).

5. The cooling device for a natural ester insulating oil power transformer according to claim 4, characterized in that: The middle heat exchange zone (15) is the overlapping area of ​​three sets of capillary heat exchange tubes (13), the upper primary cooling zone (14) is the area where the first set of capillary heat exchange tubes (13) are arranged, and the lower cooling zone (16) is the area where the third set of capillary heat exchange tubes (13) are arranged.

6. The cooling device for a natural ester insulating oil power transformer according to claim 4, characterized in that: The heat exchanger (7) is also connected to an air-cooled heat dissipation fin (17) on the outside, and two sets of capillary plates (18) for heat exchange are connected between the heat exchanger (7) and the air-cooled heat dissipation fin (17). The capillary plate (18) is arranged in the middle heat exchange zone (15), and the capillary plate (18) has through holes to accommodate the passage of the capillary heat exchange tube (13).

7. The cooling device for a natural ester insulating oil power transformer according to claim 6, characterized in that: The air-cooled heat dissipation fins (17) are aluminum fins with a fin spacing of 5-8mm.

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