Transformer sealing box and oil-immersed transformer
By installing baffles and balancing air pipes inside the transformer's sealed enclosure, the problem of unstable air pressure caused by the thermal expansion and contraction of the insulating oil in the tank was solved, resulting in a smaller transformer size and easier installation, while avoiding transformer failures.
Patent Information
- Application Number
- CN202520230540.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-02-13
- Publication Date
- 2025-11-28
- Estimated Expiration
- 2035-02-13
AI Technical Summary
When existing oil-immersed transformers are used outdoors, the unstable air pressure caused by the thermal expansion and contraction of the insulating oil in the tank leads to an increase in transformer height, which affects transportation and installation.
A partition is installed inside the transformer's sealed box to divide the space into an oil chamber and an air chamber. The pressure balance between the oil chamber and the air chamber is regulated by a balancing air pipe and a pressure balancing valve, thus avoiding the need to place the oil storage tank at the top and reducing the transformer's height.
This technology achieves a balance between the pressure in the oil and gas chambers, while reducing the overall size of the transformer, improving the convenience of transportation and installation, and preventing transformer failures and dangerous accidents.
Smart Images
Figure CN223612176U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The utility model relates to electrical equipment technical field especially, relates to a transformer sealing box and oil immersed transformer. BACKGROUND
[0002] The body of oil immersed transformer is placed in the oil tank storing insulating oil, because the transformer is usually used in outdoor environment, is greatly influenced by temperature, the insulating oil in the oil tank expands and shrinks with temperature changes, causes the pressure in the oil tank to be unstable, in order to solve this problem, the commonly used scheme of existing oil immersed transformer is to configure oil storage tank structure on the top of oil tank, and the expansion and shrinkage of transformer oil are adapted by the connection of oil storage tank and oil tank, when the oil temperature in the oil tank rises and causes the volume of insulating oil to increase, part of insulating oil enters the oil storage tank to balance the pressure in the oil tank, when the oil temperature in the oil tank decreases, the insulating oil in the oil storage tank can be supplemented into the oil tank to prevent the oil level from falling and cause the oil shortage operation of transformer.
[0003] The prior art has the following defects: the scheme of arranging the oil storage tank on the top of the transformer undoubtedly increases the height size and the occupied space of the whole transformer, causes the appearance of the transformer to be larger, on the one hand, it is inconvenient for transportation, and on the other hand, it cannot be installed and used in places with limited space.
[0004] Therefore, a transformer sealing box and oil immersed transformer are urgently needed to solve the above problems existing in the prior art. UTILITY MODEL CONTENTS
[0005] The utility model aims at providing a transformer sealing box and oil immersed transformer, which can balance the pressure inside the transformer oil tank, reduce the size of the transformer appearance, improve the appearance quality of the transformer and make transportation and installation more convenient.
[0006] To achieve this purpose, the utility model adopts the following technical scheme:
[0007] On the one hand, a transformer sealing box is provided, which comprises:
[0008] A sealing box body;
[0009] A partition plate is arranged in the sealing box body and divides the sealing box body into an oil cavity and an air cavity, and the oil cavity is configured to place the body of the transformer;
[0010] A balance air pipe, the first end of which is communicated with the oil cavity, and the second end of which is communicated with the air cavity, and a pressure balance valve is arranged on the balance air pipe;
[0011] A drain valve, which can be communicated with the air cavity, is arranged on the balance air pipe, and the drain valve is used to drain the oil in the air cavity.
[0012] As optional scheme of the transformer sealing box provided by the utility model, the sealing box body is provided with a pressure release valve, the pressure release valve can communicate with the air cavity, and is used for discharging gas in the air cavity;
[0013] And / or, the sealing box body is provided with a gas supplement valve, the gas supplement valve can communicate with the air cavity, and is used for injecting gas into the air cavity.
[0014] As optional scheme of the transformer sealing box provided by the utility model, the sealing box body is provided with a pressure monitoring module, the pressure monitoring module communicates with the air cavity, and is used for detecting the pressure value in the air cavity.
[0015] As optional scheme of the transformer sealing box provided by the utility model, the pressure monitoring module comprises a first pressure gauge and a second pressure gauge, the first pressure gauge and the second pressure gauge both communicate with the air cavity, the first pressure gauge is connected with the gas supplement valve through a control board, and the second pressure gauge is configured to be connected with a monitoring unit.
[0016] As optional scheme of the transformer sealing box provided by the utility model, the transformer sealing box further comprises an oil discharge pipe, one end of the oil discharge pipe communicates with the bottom of the air cavity, the other end of the oil discharge pipe is bent downward and has an oil discharge port, and the oil discharge port is arranged downward; the oil discharge valve is arranged on the oil discharge pipe and located between the first end and the second end of the oil discharge pipe.
[0017] As optional scheme of the transformer sealing box provided by the utility model, the transformer sealing box further comprises an oil level monitoring piece, the oil level monitoring piece is arranged on the sealing box body and is used for detecting the oil level in the oil cavity.
[0018] As optional scheme of the transformer sealing box provided by the utility model, the transformer sealing box further comprises a temperature monitoring piece, the temperature monitoring piece comprises a temperature measuring end and a first display component in communication, the temperature measuring end is inserted into the oil liquid in the oil cavity, and the first display component is located outside the sealing box body and is used for displaying the detection value of the temperature measuring end.
[0019] As optional scheme of the transformer sealing box provided by the utility model, the top wall of the sealing box body is provided with an oil injection port, and the oil injection port communicates with the oil cavity.
[0020] As optional scheme of the transformer sealing box provided by the utility model, the air pressure value in the air cavity is greater than the air pressure value of the environment outside the sealing box body;
[0021] And / or, the gas filled in the air cavity is nitrogen;
[0022] And / or, the balance gas pipe is provided with replaceable moisture absorbing pieces.
[0023] In another aspect, there is provided an oil-immersed transformer, comprising a body and a transformer sealing box as described above, the body being arranged in an oil cavity of the transformer sealing box.
[0024] The utility model discloses beneficial effect:
[0025] The utility model provides a transformer sealing box and oil-immersed transformer adopting the transformer sealing box, the inner chamber of sealing box body is divided into oil cavity and gas cavity by setting the baffle in sealing box body, the oil cavity is used for placing the body of transformer and fills the oil liquid, and the gas cavity is used for filling gas. When the oil liquid in the oil cavity is affected by the volume change of thermal expansion and cold contraction caused by temperature change, the gas pressure in the oil cavity changes, due to the existence of the balance gas pipe and the pressure balance valve arranged on the balance gas pipe, the gas in the oil cavity can be compensated to the side where the gas cavity is when the oil liquid is heated and expanded, and the gas in the gas cavity can be compensated to the side where the oil cavity is when the oil liquid is cold and contracted, until the pressure balance between the oil cavity and the gas cavity, avoiding the excessive pressure or the too small pressure in the oil cavity leading to transformer failure or dangerous accidents. When the oil temperature is too high, the oil liquid in the oil cavity may flow into the gas cavity along the balance gas pipe, and the oil liquid in the gas cavity can be discharged by opening the oil drain valve. The transformer sealing box separates the internal space into the oil cavity and the gas cavity by the baffle, does not need to set the oil storage tank on the top, can reduce the size in the height direction of transformer, reduces the appearance size of transformer, improves the appearance quality of transformer, makes transportation and installation more convenient. BRIEF DESCRIPTION OF DRAWINGS
[0026] In order to more clearly illustrate the technical scheme of the utility model embodiment, the following will be briefly introduced to the utility model embodiment needed to use the drawing, obviously, the following described drawing is only some embodiments of the utility model, for the ordinary skilled person in the art, under the premise of not paying the creative labor, still can obtain other drawings according to the drawing.
[0027] Figure 1 It is the structure diagram of transformer sealing box provided by the utility model specific embodiment;
[0028] Figure 2 It is Figure 1 The first partial view of;
[0029] Figure 3 It is Figure 1 The second partial view of;
[0030] Figure 4 It is Figure 1 The third partial view of.
[0031] In the drawing:
[0032] 1, sealed box; 2, partition; 3, balance gas pipe; 4, pressure balance valve; 5, oil drain valve; 6, pressure relief valve; 7, air supply valve; 8, pressure monitoring module; 9, oil discharge pipe; 10, temperature monitoring piece; 20, oil level monitoring piece;
[0033] 11, oil cavity; 12, gas cavity; 13, oil injection port;
[0034] 91, oil discharge port;
[0035] 101, first display component;
[0036] 201, second display component. DETAILED DESCRIPTION
[0037] The utility model will be described in further detail below in combination with the drawings and examples. It can be understood that the specific examples described here are only used to explain the utility model, and not to limit the utility model. In addition, it should be noted that in order to facilitate the description, only the part related to the utility model is shown in the drawings, not all structures.
[0038] In the description of the utility model, unless otherwise explicitly specified and limited, the terms "connected", "connected", "fixed" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or it can be integrated; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two elements or the interaction relationship of two elements. For ordinary skilled in the art, the specific meaning of the above terms in the utility model can be understood according to the specific circumstances.
[0039] In the utility model, unless otherwise explicitly specified and limited, the first feature "on" or "below" the second feature can include that the first and second features are in direct contact, or the first and second features are not in direct contact but are in contact through another feature between them. Moreover, the first feature "on", "above" and "above" the second feature includes that the first feature is directly above and obliquely above the second feature, or only indicates that the horizontal height of the first feature is higher than that of the second feature. The first feature "below", "below" and "below" the second feature includes that the first feature is directly below and obliquely below the second feature, or only indicates that the horizontal height of the first feature is less than that of the second feature.
[0040] In the description of the embodiments, the terms "upper", "lower", "left", "right", and the like, orientation or positional relationship are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of description and simplification of operation, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the utility model. In addition, the terms "first" and "second" are only used to distinguish in the description and have no special meaning.
[0041] In the embodiments of the utility model, the term "and / or" is only a description of the association relationship of the associated objects, which means that there can be three relationships, for example, A and / or B, which can represent the three cases of A existing alone, A and B existing together, and B existing alone. In addition, the character " / " in the utility model generally represents that the front and rear associated objects have an "or" relationship.
[0042] In the embodiments of the utility model, the same reference signs represent the same parts, and for the sake of brevity, the detailed description of the same parts is omitted in different embodiments.
[0043] As shown in Figure 1 The utility model provides a transformer sealing box, which comprises a sealing box body 1, a partition plate 2, a balance gas pipe 3 and a oil drain valve 5.
[0044] Combined with Figure 1 And Figure 2 The partition plate 2 is arranged in the sealing box body 1 and divides the sealing box body 1 into an oil cavity 11 and a gas cavity 12, the oil cavity 11 is configured to place the body of the transformer; the first end of the balance gas pipe 3 communicates with the oil cavity 11, the second end of the balance gas pipe 3 communicates with the gas cavity 12, and the balance gas pipe 3 is provided with a pressure balance valve 4; the oil drain valve 5 can communicate with the gas cavity 12, and the oil drain valve 5 is used for discharging oil in the gas cavity 12.
[0045] The transformer sealing box provided by the embodiments of the application divides the inner cavity of the sealing box body 1 into the oil cavity 11 and the gas cavity 12 by arranging the partition plate 2 in the sealing box body 1, the oil cavity 11 is used to place the body of the transformer and is filled with oil, and the gas cavity 12 is used to fill gas. When the oil in the oil cavity 11 expands or shrinks due to temperature change, the gas pressure in the oil cavity 11 changes accordingly. Due to the existence of the balance gas pipe 3 and the pressure balance valve 4 arranged on the balance gas pipe 3, the gas in the oil cavity 11 can be compensated to the side where the gas cavity 12 is located when the oil expands due to heat, and the gas in the gas cavity 12 can be compensated to the side where the oil cavity 11 is located when the oil shrinks due to cold, until the pressure between the oil cavity 11 and the gas cavity 12 is balanced, avoiding excessive pressure in the oil cavity 11, which can cause transformer failure or dangerous accidents.
[0046] When the oil temperature is too high, the oil in the oil cavity 11 can flow into the gas cavity 12 along the balance gas pipe 3, and the oil in the gas cavity 12 can be discharged by opening the oil discharge valve 5.
[0047] The transformer sealing box separates the internal space into the oil cavity 11 and the gas cavity 12 by the partition plate 2, does not need to set an oil storage tank on the top, can reduce the size in the height direction of the transformer, reduce the size of the transformer appearance, improve the appearance quality of the transformer, and makes transportation and installation more convenient.
[0048] Specifically, the partition plate 2 is in sealing connection with the inner wall of the sealing box body 1, such as welding connection, to avoid the gas or oil in the oil cavity 11 and the gas cavity 12 from flowing through a path other than the balance gas pipe 3.
[0049] Optionally, the first end and the second end of the balance gas pipe 3 can be provided with flange structures, and the balance gas pipe 3 is fixedly connected with the sealing box body 1 through the flange structures and ensures the sealing.
[0050] Optionally, the gas filled in the gas cavity 12 is nitrogen, which has better insulation effect and lower cost.
[0051] In the embodiment, as shown in Figure 1 and Figure 2 , the sealing box body 1 is provided with a pressure release valve 6, which can communicate with the gas cavity 12 and is used for discharging the gas in the gas cavity 12. Specifically, when the gas pressure value in the gas cavity 12 is greater than or equal to a first pressure threshold value, the gas in the gas cavity 12 is released by opening the pressure release valve 6, so that the gas pressure in the gas cavity 12 is reduced, and the deformation or explosion of the sealing box body 1 due to the excessively high gas pressure is avoided.
[0052] Exemplarily, the first pressure threshold value can be between 0.15 MPa and 0.3 MPa.
[0053] In the embodiment, as shown in Figure 1 and Figure 2 , the sealing box body 1 is provided with a gas supplement valve 7, which can communicate with the gas cavity 12 and is used for injecting gas into the gas cavity 12. When the gas pressure value in the gas cavity 12 is less than a second pressure threshold value, the gas in the gas cavity 12 is supplemented by opening the gas supplement valve 7, so as to increase the pressure value in the gas cavity 12, and avoid the damage of the sealing box body 1 due to the excessively low gas pressure.
[0054] In the embodiment, the gas pressure value in the gas cavity 12 is greater than the gas pressure value of the environment outside the sealing box body 1, that is, the inside of the gas cavity 12 is in positive pressure relative to the outside of the sealing box body 1 instead of negative pressure. In this way, once the gas cavity 12 is not tightly sealed and leaks, water and moisture cannot enter from the outside to the inside, and the safety of the transformer is ensured.
[0055] Exemplarily, the pressure value of the environment outside the sealed box body 1 is one atmospheric pressure (0.101325 MPa), and the value is the second pressure threshold.
[0056] Referring to Figure 1 and Figure 2 , the sealed box body 1 is provided with a pressure monitoring module 8 in communication with the air cavity 12, for detecting the pressure value in the air cavity 12, so as to control the opening or closing of the pressure release valve 6 and the air supplement valve 7 according to the detected pressure value, and can monitor whether the air supplement process is normal.
[0057] Specifically, the pressure monitoring module 8 includes a first pressure gauge and a second pressure gauge, both of which are in communication with the air cavity 12 and can monitor the pressure value in the air cavity 12 in real time. The first pressure gauge is communicatively connected to the control panel and the air supplement valve 7, and when the detection value of the first pressure gauge is less than the second pressure threshold, a signal is sent to the control panel, and the control panel controls the air supplement valve 7 to open, so that the air supplement device (such as a nitrogen cylinder) supplements air into the air cavity 12 through the air supplement valve 7. The second pressure gauge is communicatively connected to the monitoring unit, and can transmit the detected pressure signal to the monitoring unit. The monitoring unit is exemplarily arranged in a control room, and the operating personnel can obtain the value and change trend of the second pressure gauge in the control room through the monitoring unit, which can reflect the gas flow direction between the oil cavity 11 and the air cavity 12 during the thermal expansion and contraction of the oil, and can monitor whether the air supplement process is normal. Specifically, when the monitoring unit shows that the value of the second pressure gauge changes gradually, it proves that the gas flow direction is oil cavity 11→air cavity 12, and vice versa, when the monitoring unit shows that the value of the second pressure gauge changes gradually, it proves that the gas flow direction is air cavity 12→oil cavity 11. Combined with the change of the ambient temperature of the transformer, it can be determined whether the gas flow direction matches the temperature change, and then it can be determined whether the air supplement process is normal. For example, if the ambient temperature of the transformer gradually increases at a certain stage, the gas flow direction is oil cavity 11→air cavity 12, and the change trend of the second pressure gauge displayed by the monitoring unit should be gradually increasing. If the operating personnel observe that the pressure change trend displayed by the monitoring unit is not gradually increasing, it indicates that the air supplement process is abnormal at this time.
[0058] Further, the detection value of the second pressure gauge can also reflect the temperature of the transformer body. When the air supplement valve 7, the pressure release valve 6 and the pressure balance valve 4 are all in the closed state, ensuring that the inner cavity of the sealed box body 1 is sealed, the greater the pressure value, the higher the temperature.
[0059] As Figure 1 and Figure 3As shown, the transformer sealing box further comprises a temperature monitoring member 10, which comprises a temperature measuring end and a first display component 101 connected in communication, the temperature measuring end extends into the oil in the oil cavity 11 to detect the temperature of the oil, and the first display component 101 is located outside the sealing box body 1 to display the detection value of the temperature measuring end. The oil temperature can be read through the first display component 101 to determine whether the transformer is in a normal working temperature range.
[0060] As an example, the temperature monitoring member 10 comprises a temperature sensor, the temperature measuring end is a temperature measuring probe of the temperature sensor, and the first display component 101 is a display table or a display screen, as long as the temperature value can be read.
[0061] As shown in Figure 1 and Figure 3 , the transformer sealing box further comprises an oil level monitoring member 20 arranged in the sealing box body 1 to detect the oil level in the oil cavity 11, so as to determine whether the oil level in the oil cavity 11 is in a normal oil level range to ensure normal operation of the transformer.
[0062] Specifically, the oil level monitoring member 20 comprises a second display component 201 and a liquid level sensor connected in communication, the liquid level sensor is located inside the oil cavity 11 to detect the oil level value and display the detected oil level value through the second display component 201. By observing the display value of the second display component 201, the oil level height in the oil cavity 11 can be obtained to determine whether the oil level height meets the requirements. As an example, the second display component 201 is a display table or a display screen.
[0063] As shown in Figure 3 , the top wall of the sealing box body 1 is provided with an oil inlet 13, which is in communication with the oil cavity 11 and through which the transformer oil can be injected into the oil cavity 11. Specifically, when the oil level value detected by the oil level monitoring member 20 is lower than the set oil level threshold, the oil inlet 13 can be opened to inject oil into the oil cavity 11. During normal operation of the transformer, the oil inlet 13 is in a sealed state.
[0064] As an example, the oil inlet 13 is provided with an oil injection valve, which is opened when the oil is insufficient to inject oil through the oil inlet 13.
[0065] As shown in Figure 1 and Figure 4As shown, the transformer sealing box further comprises an oil discharge pipe 9, one end of the oil discharge pipe 9 communicates with the bottom of the air cavity 12, the other end is bent downward and has an oil discharge port 91, the oil discharge port 91 is arranged downward. The oil discharge valve 5 is arranged on the oil discharge pipe 9 and located between the first end and the second end of the oil discharge pipe 9. When the oil discharge valve 5 is opened, the oil in the air cavity 12 enters the oil discharge pipe 9 and is finally discharged through the oil discharge port 91 of the oil discharge pipe 9. Further, one end of the oil discharge pipe 9 is located at the lowest point of the air cavity 12, so as to discharge the oil in the air cavity 12 completely. By arranging the oil discharge port 91 downward, the oil can be smoothly discharged under the action of gravity, and residual oil can be avoided.
[0066] Optionally, a replaceable moisture absorbing member is arranged in the balance air pipe 3. The moisture absorbing member can dry and dehumidify the gas flowing in the balance air pipe 3, especially the gas entering the oil cavity 11, so as to avoid the influence of water and moisture in the gas on the insulation performance of the oil cavity 11. The moisture absorbing member can include a desiccant.
[0067] Further, control valves can be arranged at the connection between the balance air pipe 3 and the oil cavity 11 and the connection between the balance air pipe 3 and the air cavity 12. When the transformer is normally operated, the control valves are in an open state, so that the air supplement process can be normally performed. When the moisture absorbing member needs to be replaced, the control valves can be closed, and the two ends of the balance air pipe 3 can be disassembled, so as to take out the moisture absorbing member saturated with moisture and replace a new moisture absorbing member. At this time, the oil cavity 11 and the air cavity 12 are in a sealed state due to the closed control valves, so that impurities cannot enter the air cavity 12 and the oil cavity 11.
[0068] The embodiment also provides an oil-immersed transformer, which comprises a body and the transformer sealing box as described above, and the body is arranged in the oil cavity 11 of the transformer sealing box.
[0069] The working process of the transformer provided by the embodiment is as follows:
[0070] 1) When the transformer is in a normal working environment, the oil temperature in the oil cavity 11 of the transformer is T, the oil level value in the oil cavity 11 is L, the pressure in the oil cavity 11 is P1, and the pressure in the air cavity 12 is P2. At this time, the pressures in the oil cavity 11 and the air cavity 12 in the sealing box body 1 are balanced, that is, P1=P2.
[0071] 2) When the temperature of the working environment of the transformer rises, the oil temperature in the oil cavity 11 of the transformer is T1, T1>T. The oil level value in the oil cavity 11 is L1, the pressure in the oil cavity 11 is P3, and the pressure in the air cavity 12 is P4. Due to the physical characteristics of thermal expansion and cold contraction of the transformer oil, the oil level in the oil cavity 11 rises, L1>L, P3>P1=P2, and the pressure balance valve 4 starts to work to compensate the gas in the oil cavity 11 to the inside of the air cavity 12. When the pressures on both sides of the partition plate 2 are equal, that is, P3=P4, the pressure balance valve 4 stops working.
[0072] 3) When the temperature of the transformer working environment decreases, the oil temperature in the oil cavity 11 is T2, the oil level in the oil cavity 11 is L2, the pressure in the oil cavity 11 is P5, and the pressure in the air cavity 12 is P6. Due to the physical property of thermal expansion and cold contraction of the transformer oil, the oil level in the oil tank will decrease, L2 < L, P5 < P1 = P2, and the pressure balance valve 4 starts to work to compensate the gas in the air cavity 12 into the oil cavity 11. When the pressures on both sides are equal, i.e. P5 = P6, the pressure balance valve 4 stops working.
[0073] 4) When the temperature of the transformer working environment decreases, the oil temperature in the oil cavity 11 is T2, and the oil level in the oil cavity 11 is L2. Due to the physical property of thermal expansion and cold contraction of the transformer oil, the oil level in the oil tank will decrease, L2 < L. The oil level monitoring piece 20 monitors the oil level in the oil tank. When L2 is less than the set oil level threshold, the oil filling valve is opened in time, and the transformer oil is supplemented through the oil filling port 13 until the requirement is met.
[0074] 5) When the temperature of the transformer working environment decreases, the oil temperature in the oil cavity 11 is T2, and the pressure in the air cavity 12 of the sealed box body 1 is P6. At this time, the gas in the air cavity 12 is compensated into the oil cavity 11. The pressure value in the air cavity 12 is monitored through the pressure monitoring module 8. When P6 is less than 1 atmosphere (i.e. less than the second pressure threshold), the air supplement valve 7 is opened in time, and the gas is supplemented through the air supplement port of the air supplement valve 7 until the requirement is met, so as to avoid deformation of the sealed box body 1 due to the influence of the external atmospheric pressure.
[0075] Obviously, the above embodiments of the utility model are only examples for clearly explaining the utility model, and are not limited to the embodiments of the utility model. For ordinary skilled persons in the art, various obvious changes, re-adjustments and replacements can be made without departing from the protection scope of the utility model. Here, it is not necessary and impossible to enumerate all the embodiments. Any modification, equivalent replacement and improvement made within the spirit and principle of the utility model should be included in the protection scope of the utility model claim.
Claims
1. A transformer tank, characterized in that The transformer sealing box comprises: a sealing box body (1); a partition plate (2) arranged in the sealing box body (1) and separating the sealing box body (1) into an oil cavity (11) and a gas cavity (12), the oil cavity (11) being configured to place a body of a transformer; a balance gas pipe (3) having a first end in communication with the oil cavity (11) and a second end in communication with the gas cavity (12), the balance gas pipe (3) being provided with a pressure balance valve (4); a drain valve (5) in communication with the gas cavity (12), the drain valve (5) being used to drain oil in the gas cavity (12).
2. The transformer tank according to claim 1, characterized in that The sealing box body (1) is provided with a pressure release valve (6) in communication with the gas cavity (12) and used to drain gas in the gas cavity (12); and / or, the sealing box body (1) is provided with a gas supplement valve (7) in communication with the gas cavity (12) and used to inject gas into the gas cavity (12).
3. The transformer tank according to claim 2, characterized in that The sealing box body (1) is provided with a pressure monitoring module (8) in communication with the gas cavity (12) and used to detect a pressure value in the gas cavity (12).
4. The transformer tank according to claim 3, characterized in that The pressure monitoring module (8) comprises a first pressure gauge and a second pressure gauge, both in communication with the gas cavity (12), the first pressure gauge being communicatively connected with the gas supplement valve (7) through a control board, and the second pressure gauge being configured to be communicatively connected with a monitoring unit.
5. The transformer tank according to any of claims 1-4, characterized in that The transformer sealing box further comprises an oil drain pipe (9) having one end in communication with a bottom of the gas cavity (12) and the other end being downwardly bent and having an oil drain port (91) arranged downwardly, the drain valve (5) being arranged on the oil drain pipe (9) and located between the first end and the second end of the oil drain pipe (9).
6. The transformer tank according to any of claims 1-4, characterized in that The transformer sealing box further comprises an oil level monitoring member (20) arranged on the sealing box body (1) and used to detect an oil level in the oil cavity (11).
7. The transformer tank according to any of claims 1-4, characterized in that The transformer sealing box further comprises a temperature monitoring member (10) comprising a temperature measuring end and a first display component (101) communicatively connected, the temperature measuring end being inserted into oil in the oil cavity (11), and the first display component (101) being located outside the sealing box body (1) and used to display a detection value of the temperature measuring end.
8. The transformer tank according to any of claims 1-4, characterized in that A top wall of the sealing box body (1) is provided with an oil injection port (13) in communication with the oil cavity (11).
9. The transformer tank according to any of claims 1-4, characterized in that A gas pressure value in the gas cavity (12) is greater than a gas pressure value of an environment outside the sealing box body (1); and / or, the gas filled in the gas cavity (12) is nitrogen; and / or, the balance gas pipe (3) is provided with a replaceable moisture absorbing member.
10. An oil-immersed transformer, characterized by comprising: The transformer sealing box comprises a body and any one of the transformer sealing boxes according to claims 1-9, the body being arranged in the oil cavity (11) of the transformer sealing box.