Internal support parts of shell type transformer

Abstract

The present invention provides a transformer box for a shell-type transformer, which is used to accommodate the active part of a three-phase transformer, including transformer phases. The transformer box includes a bottom box part and a middle box part, and the bottom box part and the middle box part include a bottom plate and a wall, a cover plate, a reinforcement beam connected to the wall, an interphase plate, and a reinforcement support for reinforcing the cover plate. The interphase plate is arranged in the lower space of the transformer box and is located between adjacent transformer phases. The interphase plate extends from a side wall of the transformer box to the wall on the opposite side and is coupled with the reinforcement beam. Each reinforcement support is coupled with the interphase plate and extends to the upper space of the box between the interphase plate and the cover plate, and cooperates with the cover plate. The present invention also provides a three-phase shell-type transformer and an assembly method of the transformer.

Description

Technical Field

[0001] The present disclosure relates to a box body for a shell-type transformer, and more particularly, to a box body for a three-phase shell-type transformer.

[0002] This application claims the priority benefit of EP 18 382 802.9 filed on November 14, 2018. Background Art

[0003] The transformer tank is usually in a vacuum state, for example around 0.09 mmHg, which may cause certain areas or parts of the tank to deform inwards, such as the cover, which will rupture when the mechanical stress exceeds the ultimate tensile strength.

[0004] In addition, power transformers may be subject to internal arc energy during internal faults. The insulating fluid surrounding the active parts of the transformer may evaporate and form expanding bubbles, which will cause overpressure that may outwardly destroy the transformer tank.

[0005] When an internal arc occurs, the resulting overpressure can generate mechanical stresses in the box that exceed the ultimate tensile strength in at least certain areas or portions of the box, such as the cover, which may undergo unacceptable strain, deformation and / or rupture under low energy levels of internal arcing.

[0006] In any case, a rupture in the casing could result in oil leakage and the risk of fire.

[0007] Therefore, the transformer tank must be designed to withstand the loads caused by the working vacuum and the mechanical stress caused by internal arc faults.

[0008] To address the problem of deformation and / or cracking of the tank cover caused by the internal working vacuum and / or internal arc faults, some solutions have been developed to strengthen the cover by adding external reinforcement beams or ribs, such as welding. However, the external ribs or beams may hinder the movement of maintenance personnel and may even make walking on the transformer cover dangerous. In addition, strengthening the tank cover will reduce the mechanical configuration flexibility of this heavy structure and will also lead to higher manufacturing costs. If not designed properly, this solution, which is mainly air-cooled, will also cause overheating problems near the high-current leads.

[0009] In summary, it is desirable to provide a transformer tank that is lightweight, inexpensive to manufacture, and at the same time safe and resistant to breakage. Summary of the invention

[0010] A transformer box of a shell-type transformer is provided, which is used to accommodate the active part of a three-phase transformer including transformer phases. The box includes a bottom box part and a middle box part, a cover plate, a reinforcement beam connected to the wall, an interphase plate and a reinforcement support for reinforcing the cover plate, and the bottom box part and the middle box part include a bottom plate and a wall. The interphase plate is arranged in the lower space of the box, between adjacent transformer phases, extends from a side wall of the box to the opposite wall, and is coupled to the reinforcement beam. Each reinforcement support is coupled to the interphase plate and extends to the upper space of the box between the interphase plate and the cover plate, and cooperates with the cover plate.

[0011] By arranging such a reinforcing support member in the housing, the load and / or stress caused by the working vacuum can be transferred from the cover plate, so that the reinforcing support member can help bear the stress and avoid deformation and / or cracking of the cover plate.

[0012] The reinforcing support provides greater strength to resist inward deflection of the cover plate, which may make external supports unnecessary. Since there are fewer obstructions on the cover plate, the safety of operators, for example when inspecting the box, is also increased. In addition, since the cover plate does not require external supports and can be more flexible, the resulting structure is lighter and occupies less manufacturing cost.

[0013] When the cover plate is deformed, for example, when the cover plate is deformed inwardly, the reinforcing support member may contact the cover plate, and the contact may be direct contact or contact through an intermediate member.

[0014] The reinforcing support element can also be coupled to the cover plate directly or via an intermediate component so that inward deformation is at least prevented.

[0015] If it is also to be prevented that the cover plate is deformed significantly outwards, for example in the event of overpressure, the reinforcing support members of the embodiment can also be designed to withstand such internal positive pressure.

[0016] If it is necessary to allow a large degree of outward deformation of the cover, such as in the event of internal arc overpressure, the reinforcing support members of the embodiments may also be designed to allow such deformation.

[0017] The wall of the box body may include two opposite short walls or side walls, and two opposite long walls or front walls, thereby forming a four-wall structure with a rectangular cross section. In this case, the reinforcing beam may include a side beam and a main beam, wherein the side beam is arranged on the side wall of the box body, i.e., on the shorter wall of the box body wall, and the main beam is arranged on the front wall, i.e., on the longer wall of the box body wall. In addition, an interphase plate may be arranged between the transformer phases in the lower space of the box body, and the interphase plate may extend from the front wall of the box body to the opposite front wall and be connected to the main beam.

[0018] In one example, the reinforcing support is a hollow support that may contain conduits for circulating a coolant, thereby reducing heat generated by the magnetic flux.

[0019] In one example, each reinforcement support comprises a first portion coupled to the interphase plate and a second portion arranged to cooperate with the cover plate. Using a reinforcement support having two parts facilitates transportation and assembly of the box, for example when the size of the box makes it impossible to transport the assembled box.

[0020] In one example, the cover plate includes a connection housing in which a connection member cooperating with the reinforcing support member is arranged. The connection member may be a T-shaped member or an elongated rod, so that the support member can work under vacuum and overpressure, respectively, or only work under vacuum that allows the cover plate to partially bend.

[0021] In one example, the cover plate has no external reinforcement ribs so that operators can work more comfortably and safely when walking on the cover plate, such as when performing maintenance or accessing input / output connections.

[0022] According to a second aspect, a three-phase shell-type transformer is provided, the three-phase shell-type transformer comprising a transformer box according to any example of the present disclosure.

[0023] According to a third aspect, a method for assembling a transformer box is provided. First, each reinforcing support member is fixed to an interphase plate. Then, the box is closed with a cover plate, so that the distal end of each reinforcing support member is introduced through an opening of the bottom wall of the connecting housing. Then, a connector is inserted into the distal end of each reinforcing support member, and the removable cover plate of each connecting housing is closed. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The following is a non-limiting example of a specific embodiment of the present device, with reference to the accompanying drawings, in which:

[0025] Figure 1A and Figure 1B shows a schematic and simplified cross section of a system consisting of a three-phase shell-type transformer and a tank according to an example;

[0026] Figure 2 Shows Figure 1A and Figure 1B A partial cross-sectional schematic diagram of a box;

[0027] Figure 3A and Figure 3B shows a side view schematic diagram of a reinforcement support according to an example;

[0028] Figure 4A and Figure 4B shows a schematic cross-sectional view of a connection housing according to an example; and

[0029] Figure 5 A flow chart of a method of assembling a transformer according to an example is shown. DETAILED DESCRIPTION

[0030] Figure 1A and Figure 1B An example of a transformer 1 is shown, which may include a shell-type transformer 200, such as a three-phase shell-type transformer core including three phases 201 and a magnetic circuit 202, and a transformer box 100A, 100B (also referred to as a "box" herein), which, once closed, can withstand a vacuum of, for example, about 0.09 mmHg to maintain a negative pressure therein.

[0031] The box 100A, 100B may include a bottom box portion 104 and a middle box portion 103A, 103B. The bottom box portion 104 and the middle box portion 103A, 103B may include a bottom plate 130 and walls 120 to form a hollow space or cavity. Therefore, the box 100A, 100B may be composed of a bottom plate 130 and four walls 120 that can be connected together by, for example, welding or any other suitable means.

[0032] In one example, the box may include walls of different lengths, ie, the box may include two short walls or side walls, and two long walls or front walls, thereby forming a box with a rectangular cross-section.

[0033] In addition, the box 100A, 100B may include a reinforcing beam 160, which may be connected to the box wall 120, for example, at the middle box portion, by means of welding. The reinforcing beam 160 may be arranged around the hollow space, thereby forming an annular structure and may provide strength to the box and also help resist short-circuit loads.

[0034] In one example, the reinforcing beam 160 may include a side beam that can be connected to the side wall (ie, short wall) of the box, and a main beam that can be connected to the front wall (ie, long wall) of the box. Therefore, the side beam may be shorter than the main beam.

[0035] The box 100A, 100B may also include a cover plate 110A, 100B arranged on the top of the wall 120, so as to close the box. The cover plates 110A, 110B may be independent components, which can be manufactured and processed separately and can be connected to the structure formed by the wall 120 and the bottom plate 130 at a later stage, such as welding. Therefore, the box 100A, 100B can be transported to a predetermined location in a partially disassembled state. The active part of the transformer, i.e., the phase and magnetic circuit, can be loaded and installed in the bottom box part. The middle box part can then be installed on the active part, and then the middle box part and the bottom box part can be connected together, for example, by welding. The reinforcement beam can also be connected after the active part of the transformer is loaded. These operations can be performed in the factory. On site, the cover plate can be connected to the wall, for example, by welding, threading or any other suitable method. After that, the input / output connection can be prepared, the box can be filled with a coolant, and a vacuum can be applied.

[0036] The cover plates 110A, 110B may include a plurality of openings and / or plugs (not shown), such as input / output ports for input / output of generated current, for injection / extraction of coolant, etc. In addition, the cover plates 110A, 110B may include a connection housing 140, which may include a side wall 141, a bottom wall 142 including an opening, and a removable closure 143, thereby forming a cavity (see Figure 2 ). The closure element 143 is detachable and can be connected to / detached from the connection housing, for example by screwing, in order to gain access to the cavity of the housing.

[0037] The cover plates 110A, 110B may be made of, for example, carbon steel or other non-metallic materials, which can safely close the box and withstand the working pressure inside the box, but are flexible enough to bend under certain stress. In addition, the cover plates 110A, 110B may have a predetermined thickness, such as about 2-3.5 cm, to prevent the cover plates from bending under their own weight, and have sufficient thickness to withstand the overpressure and vacuum of normal operation without breaking.

[0038] In one example, the walls 120 , the bottom wall 130 , the reinforcement beams, and the cover plate 110 of the box may be made of the same material, such as carbon steel.

[0039] In some examples, such as Figure 1A In the example, the cover plate 110A may be a flat plate. In an alternative example, for example Figure 1B In the example of FIG. 1 , the cover plate 110B may be a U-shaped cover plate that may include a flat portion 111B, a flange 112B, and an outwardly extending portion 113B that may help connect the cover plate 110B to the wall 120 .

[0040] The box 100A, 100B may further include an interphase plate 150. The interphase plate 150 may be arranged in the lower space of the box 100A, 100B and extend from one side wall to the opposite wall 120. In the example where the box wall includes a side wall and a front wall, the interphase plate 150 may extend from the front wall of the box to the opposite front wall.

[0041] The interphase plate 150 may be connected to the reinforcing beam 160, for example, by welding. In an example, the reinforcing beam includes a main beam and a side beam, and the interphase plate 150 may be connected to the main beam.

[0042] In use, i.e. after the transformer phases are loaded, each interphase plate 150 can be arranged between adjacent transformer phases 201, and then each interphase plate can be connected to the main beam by, for example, welding. In one example, the interphase plate 150 can be a flat and / or substantially rectangular plate, which can be made of metal such as carbon steel. The interphase plate 150 provides strength to the box and also helps to withstand short-circuit loads.

[0043] In one example, the interphase plate 150 includes a magnetic shield 153 on each surface facing a transformer phase for collecting and redirecting the magnetic flux of the phase.

[0044] Figure 1A and Figure 1B The box 100A, 100B in any one of the examples may also include an elongated reinforcing support member 300, 400 to strengthen the structure of the box. The reinforcing support member 300, 400 may include a proximal end 320, 420 and a distal end 330, 430 (see Figure 3A and Figure 3B ). The proximal end 320, 420 may include a coupling member 340, 440, such as a threaded stud, for coupling the reinforcing support 300, 400 and the interphase plate 150, and the interphase plate 150 may include a complementary coupling member, such as a threaded hole. The cooperation between the reinforcing support and the interphase plate can withstand part of the mechanical stress transferred on the cover plate. The load on the cover plate and its deflection may be reduced as a result, so there is no need to add reinforcing beams or ribs on the (external) surface of the cover.

[0045] In an example, the proximal ends 320 , 420 may be rounded to minimize dielectric stress at the coupling of the reinforcing supports 300 , 400 and the interphase plate 150 .

[0046] The reinforcing support members 300 and 400 can be arranged in the upper space of the box body, between the phase plate and the cover plate, and aligned with the connection housing 140 of the cover plate, wherein the reinforcing support members can be arranged to cooperate with the cover plate. The reinforcing support members 300 and 400 can be inserted into the cavity of the connection housing through the opening of the bottom wall 142 (see Figure 4A and Figure 4B). In addition, in order to ensure that the reinforcing support can be properly adjusted in the connection housing, an adjustment component 700 of an eccentric mechanism 701, 702, for example made of fiberglass or other suitable material, can be introduced next to the reinforcing support in the connection housing (see Figure 4A and Figure 4B ). Therefore, the adjustment member 700 may be disposed between the reinforcing support member and the connection housing.

[0047] Figure 2 A simplified detail view is depicted, wherein a reinforcing support 300, 400 is coupled to a phase plate 150 and is arranged to cooperate with a cover plate 110A, 110B via a connection housing 140. The phase plate 150 may be arranged between two transformer phases 201 and may include a magnetic shield 153 on a surface facing the transformer phase 201. The reinforcing support 300, 400 may include a coupling member 340, 440, such as a threaded stud, to couple it to the phase plate. In order to protect the coupling between the reinforcing support and the phase plate, a dielectric member 134 may be added around the coupling.

[0048] The connection housing 140 of the cover plates 110A, 110B may include a removable closure 143, a side wall 141 and a bottom wall 142 to form a cavity. The connection housing may include an adjustment member 700 to correct the deviation of the reinforcing support.

[0049] The reinforcing support members 300, 400 may include a groove 331, 431 in the distal end (see Figure 3A and Figure 3B ), and includes conduits 350, 450 for coolant circulation. In addition, in an example, the reinforcing support members 300, 400 may be coated with a magnetic isolation layer (not shown).

[0050] Figure 3A A reinforcing support 300 is described, which may be a single continuous piece including a proximal end 320 and a distal end 330, which may include a groove 331. The proximal end 320 may be rounded to minimize dielectric stress and may include a coupling member 340, such as a threaded stud, for securing the reinforcing support to the interphase plate. The reinforcing support may include a conduit 350 for the circulation of a coolant, such as oil.

[0051] Generally, the boxes 100A, 100B are transported from the factory to the work site, for example by truck. However, due to, for example, local traffic restrictions and / or the capacity of the truck, the size of the box may not be suitable for transporting the entire (assembled) box, for example because it exceeds the maximum allowed size.

[0052] In this case, in order to meet the transportation requirements, the cover plate can be a U-shaped plate 110B, such as Figure 1B Thus, the use of flange 112B may allow the height of the middle and bottom box sections to be reduced compared to the height that the same sections would have if the cover plate were a flat plate.

[0053] Before loading onto the truck, the transformer phases 201 and magnetic circuits can be stacked in the bottom box section 104. Then, the middle box section 103B with reinforcement beams and interphase plates can be installed and connected to the bottom. After being closed with a transport cover (not shown), the assembly can be filled with coolant and placed in a vacuum state and transported to the work location. When the box arrives on site, the transport cover can be removed and the entire box 100B can be assembled by connecting the U-shaped cover 110B, for example, by welding.

[0054] During transportation, the vacuum and / or standard overpressure caused by the coolant may cause stresses on the cover, so the cover needs to be reinforced to avoid deformation. Similarly, once the transport cover is removed and the cover is arranged, it may also need to withstand stresses caused by at least the operating pressure, i.e., vacuum and coolant overpressure. Embodiments of the reinforcement support according to the present disclosure can be used for the above purposes.

[0055] In one example, the reinforcing support member can be divided into a first part and a second part. The length of the first part is suitable for being arranged between the interphase plate and the transport cover plate during transportation, and the second part is coupled to the first part, and when assembled together, can constitute a reinforcing support member arranged between the interphase plate and the cover plate.

[0056] Figure 3B The example depicts a reinforcing support 400, which may be divided into a first portion 401 coupled to the interphase plate and a second portion 402 arranged to be connected to the cover plate 110, for example, via a connector (see below). Figure 4A and Figure 4B ). The first part 401 and the second part 402 may each include a complementary connector 425, such as a thread, on an end surface thereof for securely connecting the two components together.

[0057] Furthermore, the first portion 401 of the reinforcing support 400 may include a connection member 440, such as a threaded stud, for fixing the first portion to the interphase plate 150, such as via a threaded hole. Figure 3A Similar to the example of , the second portion 402 may include a groove, wherein the connectors 500, 600 (see below) Figure 4A and 4B ) can be coupled.

[0058] Therefore, the length of the first part 401 of the reinforcing support 400 can correspond to the distance from the interphase plate to the transport cover. The length of the second part 402 can be such that when the two parts 401, 402 are connected together, the length of the reinforcing support 400 obtained corresponds to the distance from the interphase plate 150 to the flat portion 111B of the cover 110B.

[0059] By using a reinforcing support member formed from a first portion and a second portion, manufacturing costs and assembly time are reduced, since there is no need to manufacture and / or replace two reinforcing supports of different lengths.

[0060] The number of reinforcing supports 300, 400 arranged in the box may vary, for example, depending on the size of the cover plate, ie a larger surface may require more reinforcing supports.

[0061] In one example, each interphase plate 150 may include a reinforcing support 300, 400 disposed therein. In such an example, the reinforcing support may be substantially concentrated between the cabinet walls, for example, in an example including a side wall and a front wall, may be concentrated between the side walls.

[0062] In some examples, each interphase plate 150 of the cabinet may include two or more reinforcing supports.

[0063] The housing 100 may further include independent and separate connectors 500, 600. Each connector may be coupled to the grooves 331, 431 of the distal ends 330, 430 of the reinforcing support members 300, 400, thereby completing the internal reinforcement structure. Such an internal reinforcement structure may include interphase plates, reinforcing support members and connectors, and may provide higher strength to prevent the cover plate from flexing, for example, under overpressure or working vacuum. Depending on the form of the connectors 500, 600, the situation in which the connectors reinforce the cover plate may be different.

[0064] In one example (see Figure 4A ), the connector 500 may be a T-shaped connector. The T-shaped connector may include a lateral protrusion 502 and an extension portion 501. The connector may effectively prevent the cover plate from being deformed under a working vacuum, i.e., under an inward pulling force, and under an overpressure, i.e., under an outward pushing force.

[0065] In another example (such as Figure 4B ), the connector 600 may be an elongated rod which is particularly effective in a working vacuum environment but which may allow the cover to deform in the event of overpressure.

[0066] Figure 4AA relatively schematic cross section of the cavity of the connection housing 140 is shown. The connection housing has a bottom wall 142 with an opening, a side wall 141 and a removable closure 143, which can be fixed to the side wall 141 by, for example, screws (not shown). In the cavity of the connection housing 140, the distal ends of the reinforcing supports 300, 400, the T-shaped connector 500 inserted into the grooves 331, 431 of the reinforcing supports and the adjustment member 700, for example, a pair of eccentrics 701, 702 coupled around the distal ends of the reinforcing supports can be arranged.

[0067] In this example, the elongated portion 501 of the T-shaped member 500 can be connected to the groove 331, 431 of the reinforcing support 300, 400, for example, by screwing, and the head 502 of the T-shaped member can be placed on the adjustment member 700. Therefore, the T-shaped member can be fixedly coupled to the reinforcing support.

[0068] In addition, one or more layers of spacers, such as corrugated cardboard or pressboard 560, can be added between the removable closure 143 of the connection housing 140 and the head 502 of the T-shaped piece 500 so that the T-shaped connection fits tightly inside the connection housing. By making the T-shaped piece fit tightly, direct contact is made between the head 502 and the removable closure 143, which can reduce the impact when the two surfaces touch.

[0069] Under the working vacuum, the cover plate 110 will tend to bend inwards. The inward deformation may cause the removable closure 143 of the connecting housing to press against the corrugated board 560, and thus against the head 501 of the connecting member. Since the head of the connecting member 500 may be in direct contact with the adjustment component 700 and fixed on the reinforcing support, the stress may be transferred from the cover plate to the reinforcing support. Therefore, further deformation of the cover plate 110 may be prevented.

[0070] Under normal overpressure, the cover plate 110 tends to deform outward. The adjustment member 700 is then pushed upward by the bottom wall 142, which may cause the adjustment member 700 to push the head of the connector 500. Since the connector 500 can be fixed to the reinforcing support, the load of the cover plate 110 can be transferred to the reinforcing support members 300, 400, which can withstand the stress and thus prevent the cover plate 110 from further deformation.

[0071] exist Figure 4B In the example of FIG. 1 , a relatively schematic cross section of the cavity of the connection housing 140 is depicted, wherein Figure 4ACompared with the example of , the connecting member 600 is an extension rod. In this example, the distal ends of the reinforcing supports 300, 400, the extension rod 600 inserted and threadedly connected in the grooves 331, 431 of the reinforcing supports, and the adjustment member 700 such as a pair of eccentrics 701 and 702 coupled around the distal ends of the reinforcing supports can be arranged in the cavity of the connecting housing 140.

[0072] In this example, one or more layers of insulation, such as corrugated cardboard or pressboard 660, may be added between the removable closure 143 connected to the housing 140 and the elongated member 600 to reduce the impact when the two surfaces come into contact.

[0073] Under the working vacuum, the cover plate 110 will deform inwardly, and the removable closure member 143 of the connecting housing will therefore contact the connecting member 600, pushing the connecting member 600 toward the reinforcing support member. In the example of the interlayer including multiple layers of corrugated cardboard or pressboard, the cover plate 143 first contacts the multiple layers of interlayer. Therefore, the stress of the cover plate can be transferred to the reinforcing support member that can bear the load, so that further inward deformation of the cover plate 110 can be avoided.

[0074] In case of overpressure, Figure 4A In contrast to the example of FIG. 6 , the connector 600 cannot impose any restriction on the movement of the cover plate 110, so the cover plate 110 of the box can bend outward. Therefore, in the event of an internal arc, the box and the cover can absorb part of the energy of the expanding gas, thereby preventing the box from rupturing.

[0075] In one example, the box 100 may further include a reinforcement structure (not shown) such as a reinforcement belt, a plurality of reinforcement beams, discrete C-shaped clamps, etc., arranged on an outer surface of a wall, for example, to further strengthen the box.

[0076] Figure 5 A flow chart of a method for assembling a transformer. In one example, the assembly can be performed after being transported to a fixed location, such as by truck, and the assembled bottom box section and the middle box section have phase boards arranged therein, and the active part of the transformer is stacked therein.

[0077] First, the proximal end of each reinforcing support can be fixed to the interphase board, for example, by a coupling component, in block 801. In the example where the reinforcing support is divided into a first portion and a second portion, the method can also include connecting the second portion to the first portion, thereby assembling the reinforcing support after fixing the first portion to the interphase board.

[0078] The box can then be closed by mounting and fixing, e.g., welding, a cover plate on the wall. In block 802, the box can be closed with the cover plate so that the distal end of each reinforcing support member can be introduced through the opening of the bottom wall of the connecting housing. Thus, the reinforcing support member will be arranged in the cavity of the connecting housing so as to cooperate with the cover plate.

[0079] In one example, an adjustment member, such as a pair of assembled eccentric members, can be coupled around the reinforcing support member. The adjustment member, such as the eccentric member, can be manipulated to correctly adjust the position of the reinforcing support member relative to the connecting housing, i.e., to correct any deviation. Then, in block 803, a connector can be inserted into the distal end of each reinforcing support member, such as into a groove. In some examples, the connector can also be fixed to the support member by, for example, a threaded connection. In block 804, the removable closure member of each connecting housing can be closed by, for example, threading it to the side wall of the connecting housing.

[0080] Although the present invention discloses only some specific embodiments and examples, as will be appreciated by those skilled in the art, other alternative embodiments and / or uses and obvious modifications of the disclosed invention and their equivalents are possible. In addition, the present disclosure also includes all possible combinations of the specific embodiments. The scope of the present disclosure should not be limited by the specific embodiments, but should only be determined by a proper interpretation of the following claims.

Claims

1. A transformer box for a shell-type transformer, for accommodating the active part of a three-phase transformer including transformer phases, the box comprising: A bottom box portion and a middle box portion, wherein the bottom box portion and the middle box portion include a bottom plate and a wall; Cover plate; A reinforcing beam connected to the wall; an interphase plate, the interphase plate being arranged in the lower space of the box body and between adjacent transformer phases, the interphase plate extending from one wall of the box body to an opposite wall and coupled to the reinforcing beam, and A reinforcing support member, the reinforcing support member is used to strengthen the cover plate, wherein each support member is coupled to an interphase plate and extends in the upper space of the box body between the interphase plate and the cover plate to cooperate with the cover plate, The cover plate comprises a connecting shell, in which a connecting piece cooperating with the reinforcing support piece is arranged.

2. The transformer box according to claim 1, wherein: The reinforcing support comprises an elongated shape having a proximal end coupled to the interphase plate and a distal end arranged to mate with the cover plate.

3. The transformer box according to claim 1 or 2, wherein: The reinforcing support member is a hollow support member.

4. The transformer box according to claim 1 or 2, wherein: The reinforcing support comprises a duct for circulation of a coolant.

5. The transformer box according to claim 1 or 2, wherein: The reinforcing support member includes a first portion coupled to the interphase plate and a second portion arranged to cooperate with the cover plate.

6. The transformer box according to claim 5, wherein: The reinforcing support also includes a complementary coupling member to couple the first portion and the second portion together.

7. The transformer box according to claim 2, wherein: The reinforcement support also includes a threaded stud at the proximal end for coupling to the interphase plate.

8. The transformer box according to claim 2, wherein: The proximal end of the reinforcing support is rounded to minimize dielectric stress.

9. The transformer box according to claim 1 or 2, wherein: The connecting piece is a T-shaped piece or an elongated rod.

10. The transformer box according to claim 1 or 2, wherein: The cover plate has no external reinforcement ribs.

11. The transformer box according to claim 1 or 2, wherein: The box body includes at least two reinforcing supports connected between each interphase plate and the cover.

12. The transformer tank according to claim 1 or 2, further comprising an eccentric member arranged between the connection housing and the reinforcing support member.

13. A three-phase shell-type transformer, comprising the transformer box according to any one of claims 1 to 12.

14. A method for assembling a transformer, the transformer comprising a transformer tank according to any one of claims 1 to 12, wherein the reinforcing support member in the transformer tank comprises an elongated shape having a proximal end coupled to an interphase plate and a distal end arranged to cooperate with the cover plate, the method comprising: securing the proximal end of each reinforcing support member to the interphase plate; Closing the box body with the cover plate so that the distal end of each reinforcing support member is introduced through the opening of the bottom wall connected to the housing; inserting a connecting member into the distal end of each reinforcing support member; Close the removable cover of each connection housing.

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