An oil-immersed distribution transformer

Abstract

The application discloses an oil-immersed distribution transformer and belongs to the technical field of transformers, which comprises a transformer main body, the inside of which is filled with liquid oil medium; fins which are distributed on the outside of the transformer at equal intervals and are used for heat dissipation inside the transformer; and a high-voltage sleeve which is installed on the top of the transformer main body and is electrically connected with the inside of the transformer main body. The transformer has the beneficial effects that when the internal pressure increases due to the increase of the oil temperature during the operation of the transformer, the excess pressure drives the oil to enter the pressure regulating pipe through the connecting pipe, the oil enters the pressure relief pipe through the variable throttling channel formed by the adjustment pipe and the semicircular hole groove at the end of the pressure relief pipe, the pressure relief pipe and the pressure regulating pipe are synchronously moved outwards and the spring is compressed, the connecting pipe is elongated to complete pressure relief, when the oil temperature decreases to generate negative pressure, the spring rebounds and the outside atmosphere makes the two pipes move inwards, the connecting pipe is contracted to supplement oil, self-adapting pressure balance under all working conditions is realized, the alternating stress deformation of the shell and the sealing negative pressure air suction are prevented.

Description

Technical Field

[0001] This application relates to the field of transformer technology, and in particular to an oil-immersed distribution transformer. Background Technology

[0002] Existing oil-immersed distribution transformers generally employ a sealed tank structure, filled with insulating oil and with a small expansion margin. When the transformer load increases or the ambient temperature rises, the insulating oil expands, causing a rapid increase in pressure within the tank. Conversely, when the load drops suddenly or the ambient temperature decreases, the oil contracts, creating negative pressure inside. Due to the lack of an effective pressure regulation device, these pressure fluctuations directly affect the tank shell and sealing components, leading to the following problems:

[0003] Shell deformation: Repeated positive and negative pressure alternating stress causes fatigue deformation of the tank wall, significantly increasing the risk of weld cracking, and in severe cases, even bulging or denting.

[0004] Seal failure: The sealing gasket is excessively compressed on the high-pressure side and pulled off on the negative-pressure side. After long-term operation, the sealing performance deteriorates and oil leakage occurs.

[0005] Insulation deterioration: If the seal fails momentarily during the negative pressure stage, humid air from the outside will be drawn into the oil tank, causing the water content of the insulating oil to increase, the breakdown voltage to drop, and the insulation system to age faster.

[0006] Operation and maintenance difficulties: To avoid excessive pressure, the current approach can only increase the mechanical strength of the oil tank or reserve more expansion space, resulting in material waste and increased volume; moreover, it is impossible to monitor and adjust the internal pressure in real time, and oil needs to be drained during maintenance, resulting in high maintenance costs.

[0007] Therefore, there is an urgent need for an oil-immersed distribution transformer that can achieve adaptive internal pressure balance under all operating conditions to solve problems such as shell deformation, sealing failure and insulating oil deterioration. Summary of the Invention

[0008] One of the objectives of this application is to provide an oil-immersed distribution transformer that addresses the problem of the lack of an effective pressure regulating device in existing oil-immersed distribution transformers.

[0009] To achieve the above objectives, the technical solution adopted in this application is: an oil-immersed distribution transformer, comprising:

[0010] The transformer body is filled with liquid oil.

[0011] Fins, distributed at equal intervals on the outside of the transformer, are used for heat dissipation inside the transformer.

[0012] A high-voltage bushing is installed on the top of the transformer body and is electrically connected to the inside of the transformer body.

[0013] A low-voltage bushing is installed on one side of the high-voltage bushing and is electrically connected to the inside of the transformer body;

[0014] Also includes:

[0015] The base, located at the bottom of the transformer body, is used to support the bottom of the transformer body.

[0016] A circulation mechanism, installed inside the base, is used for circulating the liquid medium inside the transformer body;

[0017] The pressure balancing mechanism, connected to the circulation mechanism, is used to regulate the internal pressure of the transformer body.

[0018] Preferably, the circulation mechanism includes a circulation chamber, the top of which is connected to the bottom of the transformer body. A baffle is provided on one side of the circulation chamber, and a return chamber is provided on one side of the baffle. A partition is installed at the bottom of the return chamber, and the partition has equally spaced circular slots inside. The circular slots are threadedly connected to a filter bucket. The circulation chamber is connected to the input end of the circulation pump. The circulation pump is bolted to the circulation chamber, and the output end of the circulation pump is connected to the inside of the transformer body. Cooling oil enters the base through the top of the circulation chamber under the drive of the circulation pump, forming a forced circulation. The baffle and the return chamber extend the residence time of hot oil in the chamber and distribute it evenly. At the same time, the filter bucket in the slots of the partition continuously intercepts impurities in the oil, which significantly improves heat dissipation efficiency, suppresses the rise in oil temperature and pressure, and continuously purifies the oil to reduce the risk of insulation degradation. This simultaneously alleviates the problems of shell deformation, sealing failure, and insulating oil aging, and extends the maintenance cycle.

[0019] Preferably, the circulation chamber has sloping sides and a groove in the middle of the bottom. One side of the circulation chamber is connected to the bottom of a baffle by bolts. The top of the baffle is lower than the top of the circulation chamber. The filter bucket has a cup-shaped structure and its outer wall surface is multi-curved. A maintenance plate is provided on one side of the circulation chamber, and both ends of the maintenance plate are connected to the circulation chamber by bolts. The sloping chamber wall and the bottom groove automatically guide and concentrate solid impurities for sedimentation. The top of the baffle is lower than the top of the chamber, forming a low-resistance overflow channel to ensure continuous circulation. The cup-shaped multi-curved filter bucket increases the filtration area and improves the dirt-holding capacity. The side-mounted detachable maintenance plate enables quick maintenance without draining oil, thereby continuously maintaining oil cleanliness, reducing oil pressure fluctuations, delaying insulation aging, and reducing downtime.

[0020] Preferably, a collection trough is provided in the bottom groove of the circulation chamber. A limit ring is provided at one end of the collection trough, and a telescopic tube is provided inside the collection trough. One end of the telescopic tube is threadedly connected to the sealing cap. The outer wall of the telescopic tube is tightly fitted with the inner wall of the collection trough, and the outer wall of the collection trough is in sliding contact with the inner wall of the bottom groove of the circulation chamber. The collection trough sinks into the groove to directly collect sedimented impurities. Rotating the limit ring can slide the collection trough out. The threaded engagement between the telescopic tube and the sealing cap automatically seals the oil circuit when it is pulled out, realizing rapid sewage discharge without stopping the machine or draining oil, continuously maintaining the cleanliness of the oil, reducing the risk of oil pressure fluctuations and insulation aging, and reducing maintenance time and labor costs.

[0021] Preferably, the surface of the collecting tank has a perforated groove, which is aligned with the groove at the bottom of the circulation chamber by rotational fitting. The inner wall of the collecting tank slides in contact with the outer wall of the telescopic pipe. The outer wall of the limiting ring has an arc-shaped groove, which is engaged with a limiting pin at both ends by rotational fitting. The limiting pin is fixedly installed inside the circulation chamber. Rotating the collecting tank allows the perforated groove to switch between oil-flowing and closed states. The arc-shaped groove and the fixed limiting pin precisely lock the position, achieving online isolation of sedimented impurities and rapid slag discharge, preventing oil leakage, maintaining continuous operation of the circulation chamber, and continuously reducing the risk of oil pressure fluctuations and insulation aging.

[0022] Preferably, the pressure balancing mechanism includes a pressure regulating component and a sampling component. The pressure regulating component is internally connected to the circulation mechanism and is used to adaptively balance the internal pressure of the transformer body. The sampling component is installed inside the pressure regulating component and is used to collect oil samples from inside the transformer body. The pressure regulating component is directly connected to the circulation mechanism, and the pressure changes are transmitted in real time through the oil circuit to achieve adaptive pressure balance of the transformer body under all operating conditions, completely eliminating shell fatigue deformation and sealing failure caused by oil temperature rise and fall. At the same time, the embedded sampling component can complete oil sample collection without damaging the seal or stopping the machine, avoiding the intrusion of external moisture, reducing the risk of insulating oil deterioration, and reducing maintenance downtime.

[0023] Preferably, the pressure regulating assembly includes a connecting pipe, one end of which is connected to the interior of the circulation mechanism, and the other end of which is fixedly connected to one end of the pressure regulating pipe. A slip ring is fitted on the outer wall of the pressure regulating pipe, and the inner wall of the slip ring slides in contact with the outer wall of the pressure regulating pipe. The slip ring is connected to the circulation mechanism by screws. Springs are provided on both sides of the slip ring, and the springs are fitted on the outside of both ends of the pressure regulating pipe. The connecting pipe directly connects the circulation mechanism and the pressure regulating pipe, allowing changes in oil pressure to be transmitted instantaneously. The slip ring and the springs on both sides form an elastic sliding pair, enabling the pressure regulating pipe to automatically expand and contract with the rise and fall of oil pressure, absorbing or compensating for changes in oil volume in real time, achieving precise adaptive balance of internal pressure, fundamentally avoiding deformation of the shell due to alternating stress and damage to the seal, and eliminating the need for additional expansion space and reinforcing structures, thus reducing material and volume costs.

[0024] Preferably, the sampling assembly includes a pressure relief tube inserted inside a pressure regulating tube, with one end of the pressure relief tube rotatably connected to the inside of the pressure regulating tube. A sampling tube is inserted inside the pressure relief tube, and a glass observation port is provided on the surface of the sampling tube. One end of the sampling tube is threadedly connected to the inside of the pressure relief tube, and a semi-circular groove is provided at one end of the pressure relief tube. The pressure relief tube is aligned with the semi-circular groove at one end of the pressure regulating tube through rotational fitting. An indicator is provided at one end of the pressure relief tube for reference of the rotation angle. The pressure relief tube and the pressure regulating tube are coaxially sleeved and rotatable. By using the misalignment or alignment of the semi-circular groove, the system can be instantly switched between closed pressure holding and sampling channels. The external glass observation port of the sampling tube displays the oil quality status in real time, and the indicator ensures that the rotation angle is precise and controllable. This allows for oil sample collection and adaptive oil pressure balance without depressurization, shutdown, or damage to the seal, completely avoiding external moisture intrusion, eliminating the risk of insulating oil deterioration, shell deformation, and seal failure caused by sampling, and significantly reducing maintenance workload.

[0025] Preferably, the sampling tube has raised strip structures on both sides of its inner wall, and the inner wall of the sampling tube is slidably connected to the extrusion plate. The extrusion plate has grooves on both sides and is threadedly connected to a threaded rod. One end of the threaded rod has a raised structure, and the other end of the threaded rod is rotatably connected to a fixed cap at the end of the sampling tube. A knob is welded to the end of the threaded rod. The outer wall surface of the sampling tube has a slot for discharging hydraulic oil. The raised strips on the inner wall of the sampling tube and the grooves of the extrusion plate form an anti-rotation guide. Rotating the knob drives the extrusion plate to slide smoothly inside the sampling tube via the threaded rod, accurately pushing the oil sample and quantitatively discharging it from the slots on the outer wall. This allows for rapid sampling without the need for an external suction device. After sampling, rotating the extrusion plate in the opposite direction re-closes the oil circuit, maintaining the internal pressure balance and sealing integrity of the transformer throughout the process. This prevents moisture intrusion and oil leakage, effectively avoiding insulation oil deterioration, shell fatigue deformation, and sealing failure, and significantly reducing maintenance time and costs.

[0026] Compared with the prior art, the beneficial effects of this application are as follows:

[0027] During operation, the cooling oil is forced back by the circulation mechanism after being cooled by the fins. When the oil temperature rises, causing the internal pressure to increase, the excess pressure pushes the oil through the connecting pipe into the pressure regulating pipe. It then enters the pressure relief pipe through the variable throttling channel formed by aligning the semi-circular slots at the ends of the regulating pipe and the pressure relief pipe. This drives the pressure relief pipe and the pressure regulating pipe to move outward synchronously and compress the spring, causing the connecting pipe to extend and complete the pressure relief. When the oil temperature drops and negative pressure is generated, the spring rebound and the external atmosphere cause the two pipes to move inward, and the connecting pipe contracts to replenish oil, achieving adaptive pressure balance under all operating conditions. This prevents deformation of the shell due to alternating stress and air intake due to negative pressure in the seal. When sampling is required, the sampling tube is first rotated out and the pressure relief pipe is rotated to make the two semi-circular slots misalign and seal the oil passage. Then, the knob is turned to drive the threaded rod to rotate. The threaded rod pushes the extrusion plate to slide along the inner wall of the sampling tube, discharging a quantitative oil sample through the slots in the sampling tube wall. This completes convenient sampling without draining oil, stopping the machine, or damaging the seal, preventing moisture intrusion, extending insulation life, and reducing maintenance costs. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the overall structure of the present invention.

[0029] Figure 2 This is a schematic diagram of the internal structure of the base of the present invention.

[0030] Figure 3 This is a schematic diagram of the partition structure of the present invention.

[0031] Figure 4 This is a schematic diagram of the circulating pump structure of the present invention.

[0032] Figure 5 This is a schematic diagram of the circulating mechanism structure of the present invention.

[0033] Figure 6 This is a schematic diagram of the pressure balancing mechanism of the present invention.

[0034] Figure 7 This is a schematic diagram of the threaded rod structure of the present invention.

[0035] Figure 8 This is a schematic diagram of the sampling tube structure of the present invention.

[0036] In the diagram: 1. Transformer body; 2. Fins; 3. High-voltage bushing; 4. Base; 5. Low-voltage bushing; 6. Circulation mechanism; 601. Circulation chamber; 602. Return chamber; 603. Baffle; 604. Filter hopper; 605. Circulation pump; 606. Baffle; 607. Collection tank; 608. Limiting ring; 609. Limiting pin; 610. Telescopic tube; 611. Sealing cover; 612. Inspection plate; 7. Pressure balancing mechanism; 701. Connecting tube; 702. Slip ring; 703. Pressure regulating tube; 704. Spring; 705. Pressure relief tube; 706. Threaded rod; 707. Extrusion plate; 708. Fixing cover; 709. Knob; 710. Sampling tube. Detailed Implementation

[0037] The present application will be further described below with reference to specific embodiments. It should be noted that, without conflict, the various embodiments or technical features described below can be arbitrarily combined to form new embodiments.

[0038] In the description of this application, it should be noted that the directional terms such as "center", "lateral", "longitudinal", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", and "counterclockwise" indicate the orientation and positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. They should not be construed as limiting the specific protection scope of this application.

[0039] It should be noted that the terms "first," "second," etc., in the specification and claims of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence.

[0040] Example 1:

[0041] One preferred embodiment of this application, such as Figures 1 to 8 As shown, an oil-immersed distribution transformer includes: a transformer body 1, which is filled with liquid oil; fins 2, which are evenly spaced on the outside of the transformer for internal heat dissipation; a high-voltage bushing 3, which is installed on the top of the transformer body 1 and electrically connected to the inside of the transformer body 1; a low-voltage bushing 5, which is installed on one side of the high-voltage bushing 3 and electrically connected to the inside of the transformer body 1; and further includes: a base 4, located at the bottom of the transformer body 1 for supporting the bottom of the transformer body 1; a circulation mechanism 6, installed inside the base 4 for circulating the liquid medium inside the transformer body 1; and a pressure balancing mechanism 7, connected to the circulation mechanism 6 for regulating the internal pressure of the transformer body 1.

[0042] This embodiment integrates a circulation mechanism 6 within the base 4 at the bottom of the transformer body 1 to force the cooling oil to circulate and dissipate heat, effectively suppressing volume expansion caused by rising oil temperature and thus significantly reducing internal pressure peaks. Simultaneously, the pressure balancing mechanism 7, directly connected to the circulation mechanism 6, automatically absorbs or compensates for oil volume changes when the load or ambient temperature changes, achieving real-time adaptive balance of internal pressure. This completely avoids fatigue deformation and weld cracking of the shell caused by repeated positive and negative pressure alternating stress, eliminates oil leakage caused by high-pressure squeezing or negative pressure pull-out of the sealing gasket, and prevents external humid air from entering the oil tank during negative pressure stages, which could cause an increase in the water content of the insulating oil and a drop in breakdown voltage. This extends the life of the insulation system and enables online maintenance without draining oil or stopping the machine without increasing the oil tank volume or improving the material strength grade, significantly reducing operation and maintenance costs.

[0043] Example 2:

[0044] One preferred embodiment of this application, such as Figures 1 to 8 As shown, the pressure balancing mechanism 7 includes a pressure regulating component and a sampling component. The pressure regulating component is internally connected to the circulation mechanism 6. The pressure regulating component is used to adaptively balance the internal pressure of the transformer body 1. The sampling component is installed inside the pressure regulating component and is used to collect oil samples from inside the transformer body 1. The pressure regulating component includes a connecting pipe 701. One end of the connecting pipe 701 is internally connected to the circulation mechanism 6, and the other end of the connecting pipe 701 is fixedly connected to one end of the pressure regulating pipe 703. A slip ring 702 is fitted on the outer wall of the pressure regulating pipe 703. The inner wall of the slip ring 702 slides in contact with the outer wall of the pressure regulating pipe 703. The slip ring 702 is connected to the circulation mechanism 6 by screws. Springs 704 are provided on both sides of the slip ring 702 and are fitted on the outside of both ends of the pressure regulating pipe 703. The sampling component includes a pressure relief pipe 705, which is inserted inside the pressure regulating pipe 703. One end of the pressure relief pipe 705 is connected to the pressure regulating pipe 703. Internally, a rotating connection is made in tube 703. A sampling tube 710 is inserted inside the pressure relief tube 705. The sampling tube 710 has a glass observation port on its surface, and one end of the sampling tube 710 is threaded into the pressure relief tube 705. One end of the pressure relief tube 705 has a semi-circular groove, which is aligned with the semi-circular groove at one end of the pressure regulating tube 703 via a rotational fit. An indicator mark is provided at one end of the pressure relief tube 705 for reference to the rotation angle. The inner wall of the sampling tube 710 has... The sampling tube 710 has a raised strip structure and its inner wall is slidably connected to the extrusion plate 707. The extrusion plate 707 has grooves on both sides and is threadedly connected to the threaded rod 706. One end of the threaded rod 706 has a raised structure and the other end of the threaded rod 706 is rotatably connected to the fixing cap 708 at the end of the sampling tube 710. A knob 709 is welded to the end of the threaded rod 706. The outer wall surface of the sampling tube 710 has a hole groove for discharging hydraulic oil.

[0045] In this embodiment, the transformer's internal cooling oil dissipates heat through the fins 2 during operation. The cooling oil then circulates from the base 4 via the circulation mechanism 6. Simultaneously, influenced by temperature, when the internal pressure of the transformer is high, the excess pressure forces the internal cooling oil through the connecting pipe 701 into the pressure regulating pipe 703. The semi-circular groove at one end of the pressure regulating pipe 703 aligns with the semi-circular groove at one end of the pressure relief pipe 705, allowing the cooling oil to enter the pressure relief pipe 705. Under pressure, this pushes the pressure relief pipe 705 and the pressure regulating pipe 703 outwards. When the pressure regulating pipe 703 is squeezed, the spring 704 at one end of the pressure regulating pipe 703 is stretched. Under the action of the pressure relief pipe 705 and the pressure regulating pipe 703, the connecting pipe 701 is stretched, so that the pressure inside the transformer body 1 can be released and balanced. Similarly, when the pressure inside the transformer body 1 is small, under the action of the suction inside the transformer body 1, the pressure regulating pipe 703 and the pressure relief pipe 705 can move into the circulation mechanism 6, so that the connecting pipe 701 will contract. In this way, the pressure inside the transformer body 1 can be self-adaptively balanced, which helps to avoid the deformation of the transformer shell and the intake of external air at the seal.

[0046] When it is necessary to sample the cooling oil inside the transformer body 1, the sampling tube 710 is rotated, allowing it to be pulled outward a certain distance. The pressure relief tube 705 is rotated, causing the semi-circular groove at one end of the pressure relief tube 705 to be misaligned with the semi-circular groove at one end of the pressure regulating tube 703, thus sealing the inside of the sampling tube 710. Then, the knob 709 is rotated, causing the threaded rod 706 to rotate. As the threaded rod 706 rotates, it drives the extrusion plate 707 to move, thereby extruding the cooling oil inside the sampling tube 710. This allows the cooling oil to be easily discharged from the groove on the surface of the sampling tube 710, improving the convenience of sampling.

[0047] Example 3:

[0048] One preferred embodiment of this application, such as Figures 1 to 8As shown, the circulation mechanism 6 includes a circulation chamber 601. The top of the circulation chamber 601 is connected to the bottom of the transformer body 1. A baffle 606 is provided on one side of the circulation chamber 601, and a return chamber 602 is provided on one side of the baffle 606. A partition 603 is installed at the bottom of the return chamber 602, and the partition 603 has equally spaced circular slots. The circular slots are threadedly connected to the filter bucket 604. The circulation chamber 601 is connected to the input end of the circulation pump 605. The circulation pump 605 is bolted to the circulation chamber 601, and the output end of the circulation pump 605 is connected to the inside of the transformer body 1. The two sides of the circulation chamber 601 are sloping, and a groove is provided in the middle of the bottom of the circulation chamber 601. One side of the circulation chamber 601 is bolted to one end of the bottom of the baffle 606. The top end of the baffle 606 is lower than the top of the circulation chamber 601. The filter bucket 604... 4. The filter hopper 604 has a cup-shaped structure and its outer wall surface is multi-curved. A maintenance plate 612 is provided on one side of the circulation chamber 601. The two ends of the maintenance plate 612 are connected to the circulation chamber 601 by bolts. A collection trough 607 is provided in the bottom groove of the circulation chamber 601. A limit ring 608 is provided at one end of the collection trough 607. The outer wall of the telescopic tube 610 is in close contact with the inner wall of the collection trough 607. The outer wall of the collection trough 607 is in sliding contact with the inner wall of the bottom groove of the circulation chamber 601. The surface of the collection trough 607 has a hole groove, and the hole groove on the surface of the collection trough 607 is aligned with the bottom groove of the circulation chamber 601 by rotational fit. The inner wall of the collection trough 607 is in sliding contact with the outer wall of the telescopic tube 610. The outer wall of the limit ring 608 has an arc-shaped groove, and the two ends of the arc-shaped groove on the surface of the limit ring 608 are engaged with the limit pin by rotational fit. The limit pin is fixedly installed inside the circulation chamber 601.

[0049] Under the action of the circulating pump 605, the oil inside the transformer body 1 can enter the circulating chamber 601, and the impurities in the oil can settle in the groove at the bottom of the circulating chamber 601, and then fall into the collection tank 607 for collection. By rotating the collection tank 607 180 degrees, the holes and grooves on the surface of the collection tank 607 are misaligned with the groove at the bottom of the circulating chamber 601, and the sealing cover 611 is opened, so that the impurities settled inside the collection tank 607 can be discharged from one end. At the same time, it helps to prevent the oil inside the circulating chamber 601 from communicating with the outside and being discharged. During the circulation process, the internal cooling oil can be filtered through multiple filter hoppers 604, thereby filtering out the remaining impurities inside the cooling oil, which helps to extend the service life of the cooling oil.

[0050] The basic principles, main features, and advantages of this application have been described above. Those skilled in the art should understand that this application is not limited to the above embodiments. The embodiments and descriptions in the specification are merely the principles of this application. Various changes and modifications can be made to this application without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claims. The scope of protection claimed by this application is defined by the appended claims and their equivalents.

Claims

1. An oil-immersed distribution transformer, comprising: The transformer body (1) is filled with liquid oil medium; Fins (2) are distributed at equal intervals on the outside of the transformer for heat dissipation inside the transformer. High-voltage bushing (3) is installed on the top of the transformer body (1) and is electrically connected to the inside of the transformer body (1); The low-voltage bushing (5) is installed on one side of the high-voltage bushing (3) and is electrically connected to the inside of the transformer body (1); Its characteristic is that it further includes: The base (4) is located at the bottom of the transformer body (1) and is used to support the bottom of the transformer body (1). The circulation mechanism (6) is installed inside the base (4) and is used for the circulation of liquid medium inside the transformer body (1); The pressure balancing mechanism (7) is connected to the circulation mechanism (6) and is used to regulate the internal pressure of the transformer body (1); The pressure balancing mechanism (7) includes a pressure regulating component and a sampling component. The pressure regulating component is internally connected to the circulation mechanism (6). The pressure regulating component is used to adaptively balance the internal pressure of the transformer body (1). The sampling component is installed inside the pressure regulating component and is used to collect oil samples from inside the transformer body (1). The pressure regulating assembly includes a connecting pipe (701), one end of which is connected to the inside of the circulation mechanism (6), and the other end of which is fixedly connected to one end of the pressure regulating pipe (703). A slip ring (702) is fitted on the outer wall of the pressure regulating pipe (703). The inner wall of the slip ring (702) is in sliding contact with the outer wall of the pressure regulating pipe (703). The slip ring (702) is connected to the circulation mechanism (6) by screws. Springs (704) are provided on both sides of the slip ring (702). The springs (704) are fitted on the outside of both ends of the pressure regulating pipe (703). The sampling assembly includes a pressure relief tube (705), which is inserted inside the pressure regulating tube (703). One end of the pressure relief tube (705) is rotatably connected to the inside of the pressure regulating tube (703). A sampling tube (710) is inserted inside the pressure relief tube (705). A glass observation port is provided on the surface of the sampling tube (710). One end of the sampling tube (710) is threaded to the inside of the pressure relief tube (705). One end of the pressure relief tube (705) is provided with a semi-circular groove. The pressure relief tube (705) is aligned with the semi-circular groove at one end of the pressure regulating tube (703) by rotational fitting.

2. The oil-immersed distribution transformer as described in claim 1, characterized in that: The circulation mechanism (6) includes a circulation chamber (601), the top of which is connected to the bottom of the transformer body (1), and a baffle (606) is provided on one side of the circulation chamber (601). A return chamber (602) is provided on one side of the baffle (606). A partition (603) is installed at the bottom of the return chamber (602), and the partition (603) has circular slots at equal intervals inside, and the circular slots are threaded to the filter bucket (604). The circulation chamber (601) is connected to the input end of the circulation pump (605), and the circulation pump (605) is connected to the circulation chamber (601) by bolts. The output end of the circulation pump (605) is connected to the inside of the transformer body (1).

3. The oil-immersed distribution transformer as described in claim 2, characterized in that: The circulation chamber (601) has sloping sides inside and a groove in the middle of the bottom. One side of the circulation chamber (601) is connected to the bottom of the baffle (606) by bolts. The top of the baffle (606) is lower than the top of the circulation chamber (601). The filter bucket (604) has a cup-shaped structure and the outer wall surface of the filter bucket (604) is multi-curved. A maintenance plate (612) is provided on one side of the circulation chamber (601). Both ends of the maintenance plate (612) are connected to the circulation chamber (601) by bolts.

4. The oil-immersed distribution transformer as described in claim 3, characterized in that: A collection trough (607) is provided in the bottom groove of the circulation chamber (601). A limit ring (608) is provided at one end of the collection trough (607), and a telescopic tube (610) is provided inside the collection trough (607). One end of the telescopic tube (610) is threadedly connected to the sealing cap (611). The outer wall of the telescopic tube (610) is tightly fitted with the inner wall of the collection trough (607), and the outer wall of the collection trough (607) slides in contact with the inner wall of the bottom groove of the circulation chamber (601).

5. An oil-immersed distribution transformer as described in claim 4, characterized in that: The surface of the collection tank (607) is provided with a hole, and the hole on the surface of the collection tank (607) is aligned with the bottom groove of the circulation chamber (601) by rotational fit. The inner wall of the collection tank (607) is in sliding contact with the outer wall of the telescopic tube (610). The outer wall of the limiting ring (608) is provided with an arc-shaped groove, and the arc-shaped groove on the surface of the limiting ring (608) is engaged with the limiting pin (609) at both ends by rotational fit. The limiting pin (609) is fixedly installed inside the circulation chamber (601).

6. An oil-immersed distribution transformer as described in claim 1, characterized in that: The sampling tube (710) has raised strip structures on both sides of its inner wall, and the inner wall of the sampling tube (710) is slidably connected to the extrusion plate (707). The extrusion plate (707) has grooves on both sides, and the extrusion plate (707) is threadedly connected to the threaded rod (706). One end of the threaded rod (706) has a raised structure, and the other end of the threaded rod (706) is rotatably connected to the fixed cap (708) at the end of the sampling tube (710). A knob (709) is welded to the end of the threaded rod (706). The outer wall surface of the sampling tube (710) has a hole groove for discharging hydraulic oil.

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