Frame-type oil pool and medium-voltage transformer substation using same

Abstract

The invention relates to the technical field of transformer substations, in particular to a frame-type oil pool and a medium-voltage transformer substation applying the same, and the frame-type oil pool comprises a frame-type main body and an oil pool; the frame type main body comprises an upper frame and a lower frame, and the upper frame and the lower frame are both square frames; the upper frame is fixed above the lower frame through four supporting columns, the four supporting columns are located at the four corners of the upper frame and the four corners of the lower frame respectively, and a hollow space is defined by the upper frame, the lower frame and the four supporting columns. The oil pool is installed in the middle of the hollow space and divides the hollow space into two hollow subspaces. The technical problems of cost and scene limitation, design and standard adaptation and the like of an existing concrete oil pool can be solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of transformer substations, and in particular to a frame type oil pool and a medium voltage transformer substation using the same. BACKGROUND

[0002] In the construction process of a medium voltage transformer substation, an oil pool, as an important supporting facility, undertakes a key function. In the prior art, a concrete construction scheme is generally used for a medium voltage transformer substation oil pool. This scheme has significant limitations, as follows: (1) Cost and scene limitation problem: The construction cost of a concrete oil pool is relatively high, and it is limited by the characteristics of the concrete structure, which has strict requirements on the terrain. In complex terrain areas such as mountains and hills, the construction difficulty of a concrete oil pool is greatly increased, and even it is difficult to carry out construction work, which seriously limits the use scene of the oil pool and cannot meet the construction needs of the medium voltage transformer substation under different terrain conditions.

[0003] (2) Design and standard adaptation problem: Different regions have formulated various and differentiated standards for building construction, and a concrete oil pool needs to be designed separately according to the standards of each region. This not only increases the design difficulty of the tenderer, but also prolongs the design cycle, resulting in low efficiency of the preliminary preparation work of the oil pool construction project, which is not conducive to the rapid progress of the project.

[0004] Therefore, there is an urgent need for a medium voltage transformer substation oil pool that can reduce costs, adapt to various scenes and meet the requirements of standardized design to solve the above problems existing in the existing concrete oil pool. SUMMARY

[0005] One purpose of the present application is to provide a frame type oil pool to solve the technical problems of cost and scene limitation, design and standard adaptation of the existing concrete oil pool.

[0006] Another purpose of the present application is to provide a transformer substation installed in the frame type oil pool described above.

[0007] To achieve this purpose, the present application adopts the following technical solutions: A frame type oil pool, comprising a frame type main body and an oil pool; The frame type main body comprises an upper frame and a lower frame, and the upper frame and the lower frame are both square frames; The upper frame is fixed above the lower frame by four support columns, the four support columns are respectively located at the four corners of the upper frame and the lower frame, and the upper frame, the lower frame and the four support columns enclose a hollow space; The oil pool is installed in the middle of the hollow space and divides the hollow space into two hollow subspaces.

[0008] Preferably, the upper frame and the lower frame have the same structure, and each of the upper frame and the lower frame comprises two long square tubes and two short square tubes; The two long square tubes and the two short square tubes are sequentially welded to form the square frame; The four support columns are respectively welded at four corners of the two square frames; The four corners of the two square frames are each provided with a corner pad.

[0009] Preferably, the frame body further comprises a plurality of grounding seats, and the plurality of grounding seats are mounted on the outer periphery of the lower frame.

[0010] Preferably, the outer periphery of the oil pool is fixed with a plurality of reinforcing ribs.

[0011] Preferably, the bottom of the oil pool is provided with a pad strip.

[0012] Preferably, an oil-water treatment device is mounted in the oil pool, and the oil-water treatment device comprises a plurality of siphon pipes; The plurality of siphon pipes are fixedly mounted on the inner side wall of the oil pool, the water inlet of the siphon pipe is lower than the normal oil level of the oil pool, and the water outlet of the siphon pipe extends to the outside of the oil pool.

[0013] Preferably, the frame body is made of high-strength lightweight steel.

[0014] A medium-voltage transformer substation comprises a first voltage cabinet, a medium-voltage transformer box and a second voltage cabinet, and the first voltage cabinet, the medium-voltage transformer box and the second voltage cabinet are mounted on a frame-type oil pool as described above. The medium-voltage transformer box is mounted above the oil pool, and the first voltage cabinet and the second voltage cabinet are respectively mounted above the hollow subspaces for the cables of the first voltage cabinet and the cables of the second voltage cabinet.

[0015] One of the above technical solutions has the following beneficial effects: (1) greatly reducing the cost and improving the economy: ① Material cost: the frame body can be made of lightweight materials such as steel, which requires less material and lower procurement cost than the large amount of sand and cement required for a concrete oil pool; ② Construction cost: unlike a concrete oil pool, the frame and the oil pool can be pre-fabricated in a factory and assembled on site, reducing the construction period and labor cost; ③ Transportation cost: the frame structure supports the stacking and transportation of multiple oil pools, greatly improving the utilization rate of transportation space and reducing the transportation cost of each oil pool, especially for sea transportation export scenarios.

[0016] (2) Break through scene limitations and improve adaptability: ① Terrain adaptability: The frame structure does not require a flat construction base. In complex terrain areas such as mountains and hills, stable installation can be achieved by adjusting the frame fixing method, such as lengthening the support columns and laying leveling components. This solves the problem that concrete oil tanks are difficult to construct in complex terrains and cannot be built. ② Functional adaptation: The two hollowed-out sub-spaces formed by the oil tank partition can be directly used as cable channels without the need for additional cable holes. This adapts to the connection requirements of low-voltage and medium-voltage cables in substations, avoids damage to the oil tank structure due to cable wiring, and reduces the cost of later modifications.

[0017] (3) Achieve standardized design and reduce design difficulty: The "square frame + four corner supports" structure of the main frame has a high degree of standardization. There is no need to adjust the frame size and structure according to the construction standards of different regions. Bidders do not need to design oil tank structures separately for different projects. They can directly adopt the unified standard for production and installation, shorten the design cycle, reduce design difficulty, and solve the problem of "diverse oil tank construction standards leading to low design efficiency" in the existing technology.

[0018] (4) Improve maintenance convenience and extend service life: The open hollow sub-space of the frame structure makes it easy for staff to conduct daily inspections, cleaning and maintenance of the oil tank, without the problem of "difficulty in accessing the interior of the oil tank due to the closed structure" faced by concrete oil tanks; at the same time, the oil tank is protected by the frame structure, which can reduce the erosion of the oil tank by external environment such as rainwater erosion and debris collision, and extend the service life of the oil tank. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of a frame-type oil tank. Figure 2 This is a schematic diagram of a frame-type oil tank concealing an oil tank and a siphon pipe; Figure 3 This is a structural schematic diagram of a medium-voltage substation installed in a frame-type oil tank as described above; In the attached diagram: frame-type main body 1, upper frame 11, lower frame 12, support column 13, rectangular tube 111, short square tube 112, oil tank 2, grounding seat 4, reinforcing rib 5, pad strip 6, siphon tube 7, first voltage cabinet 10, medium voltage transformer box 20, second voltage cabinet 30, frame-type oil tank 40. Detailed Implementation

[0020] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0021] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "left," "right," "vertical," "level," "top," "bottom," "inner," "outer," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0022] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0023] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0024] like Figures 1-2 As shown, a frame-type oil tank includes a frame-type main body 1 and an oil tank 2. The frame-type main body 1 includes an upper frame 11 and a lower frame 12, both of which are square frames. The upper frame 11 is fixed above the lower frame 12 by four support columns 13. The four support columns 13 are located at the four corners of the upper frame 11 and the lower frame 12 respectively. The upper frame 11, the lower frame 12 and the four support columns 13 enclose a hollow space. The oil tank 2 is installed in the middle of the hollow space, and divides the hollow space into two hollow sub-spaces 3.

[0025] This frame-type oil tank is based on the design of "modular frame support + intermediate oil tank for oil storage + hollow space for adaptation". Combined with the functional requirements and actual application scenarios of medium-voltage substation oil tank 2, its specific working principle is as follows: The frame structure 1 consists of an upper frame 11, a lower frame 12, and four supporting columns 13. Both the upper frame 11 and the lower frame 12 adopt a square structure, and the four supporting columns 13 are fixed to the four corners of both, forming a three-dimensional frame structure of "upper and lower frames + four corner supports". This structure can evenly distribute the oil tank 2 and external loads (such as the weight of substation equipment and the pressure during stacked transportation) through the supporting columns 13, ensuring that the frame as a whole has sufficient load-bearing strength, avoiding structural deformation due to excessive local stress, and providing basic support for the stable installation and use of the oil tank 2.

[0026] The oil tank 2 is installed in the middle of the hollow space formed by the frame-type main body 1. On the one hand, the installation method in the middle position can form a surrounding protection for the oil tank 2 with the help of the frame structure, reducing the impact of external collisions and terrain fluctuations on the oil tank 2. On the other hand, the oil tank 2 divides the hollow space into two independent hollow sub-spaces 3, which not only ensures that the oil tank 2 itself has sufficient oil storage space, but also provides channels for cable wiring, equipment connection and other purposes through the hollow sub-spaces 3 on both sides, which can meet the supporting needs of the substation.

[0027] When installed in areas with complex terrain, the modular structure of the frame main body 1 can flexibly adapt to different ground conditions (such as slight slopes and uneven ground). Stable installation can be achieved by adjusting the fixing method of the lower frame 12 to the ground (in conjunction with the external L-shaped fixing plate), without relying on a flat construction base surface like concrete oil tanks. In transportation scenarios, the regular shape and lightweight characteristics of the frame structure (compared to concrete) allow multiple oil tanks 2 to be stacked. The corresponding structure of the upper frame 11 and the lower frame 12 can ensure the accuracy of alignment during stacking, avoiding displacement or damage of the oil tanks 2 during transportation.

[0028] To further explain, the upper frame 11 and the lower frame 12 have the same structure, and both the upper frame 11 and the lower frame 12 include two rectangular tubes 111 and two short rectangular tubes 112. The two rectangular tubes 111 and the two short square tubes 112 are welded together in sequence to form the square frame; The four support columns 13 are respectively welded to the four corners of the two square frames; Corner protectors 8 are provided at the four corners of both square frames.

[0029] Specifically, the upper frame 11 and the lower frame 12 have the same structure, both consisting of two long rectangular tubes 111 and two short rectangular tubes 112 welded together to form a square frame. The welding process achieves a rigid connection between the long rectangular tubes 111 and the short rectangular tubes 112, ensuring the square frame has complete structural integrity and avoiding the component loosening problem that may occur in assembled structures. Four support columns 13 are welded to the four corners of the two square frames respectively, further connecting the upper frame 11 and the lower frame 12 into a three-dimensional frame main body 1. This allows the overall force of the frame main body 1 to be evenly transferred through the welding nodes: the weight of the oil tank, the oil storage load, and the additional weight of the substation equipment are first applied to the upper frame 11, then transferred to the lower frame 12 through the four corner support columns 13, and finally distributed to the ground.

[0030] Meanwhile, corner protectors 8 are installed at each of the four corners of the two square frames, directly covering the welded joints and ends of the poles at the four corners of the square frames. In transportation scenarios (such as sea freight export and on-site handling), the four corners of the square frames are prone to collisions with transport vehicles and other objects. The corner protectors 8 can absorb the impact force through their own elastic or rigid buffer structure, preventing the welded joints at the four corners of the square frames from cracking and the poles from deforming. In installation scenarios, the corner protectors 8 can prevent workers from being injured by contact with the sharp corners of the frames, and at the same time prevent the corners of the frames from directly contacting the ground or other equipment, thus protecting the structural integrity of the frames.

[0031] The hollow space formed by the three-dimensional frame main body 1 provides a carrier for the installation of oil tank 2, and oil tank 2 can be fixed in the hollow space; at the same time, the frame structure retains the core advantages of "easy to transport and adaptable to cable wiring" - the assembled three-dimensional frame can adapt to the stacked transportation requirements; the hollow areas on both sides of the frame main body 1 can meet the unrestricted connection requirements of voltage cabinet cables, forming a synergy with the overall function of oil tank 2.

[0032] To further explain, the frame-type main body 1 also includes a plurality of grounding bases 4, which are installed on the outer periphery of the lower frame 12.

[0033] Multiple grounding bases 4 are fixedly installed on the outer periphery of the lower frame 12. This installation position avoids spatial interference between the grounding bases 4 and the main body of the oil tank 2, the support column 13, and other structures, while ensuring that the grounding bases 4 are close to the ground, facilitating quick connection with the substation's grounding system (such as grounding electrodes and grounding trunk lines). The grounding bases 4 are connected to the outer periphery of the lower frame 12 by bolts or welding (compatible with the material of the lower frame 12), ensuring a firm connection and stable transmission of static or leakage current.

[0034] To further explain, the outer periphery of the oil tank 2 is fixed with multiple reinforcing ribs 5.

[0035] Multiple reinforcing ribs 5 are evenly fixed along the outer perimeter of the oil tank 2 (they can be connected to the outer wall of the oil tank 2 by welding, bolting, etc.), and their arrangement direction can be designed according to the stress characteristics of the oil tank 2 (such as horizontal, longitudinal, or diagonal cross distribution). When the oil tank 2 stores oil, the oil will exert outward pressure on the wall of the oil tank 2. The reinforcing ribs 5 disperse this pressure through their own rigid structure, preventing the wall of the oil tank 2 from deforming due to excessive local stress; at the same time, they can also serve as an auxiliary structure for force transmission between the oil tank 2 and the frame body, reducing stress concentration at the connection between the oil tank 2 and the frame body 1, and further strengthening the overall deformation resistance of the oil tank 2.

[0036] To further explain, a pad 6 is provided at the bottom of the oil tank 2.

[0037] Specifically, the pad strip 6 is fixed to the bottom of the oil tank 2 (it can be connected by welding, bolts or adhesive, depending on the material of the oil tank 2 and the material of the pad strip 6). Its arrangement direction and quantity can be designed according to the weight distribution of the oil tank 2 and the load-bearing area of ​​the frame body 1, such as being evenly distributed along the length or width of the oil tank 2.

[0038] When the oil tank 2 is installed in the hollow space enclosed by the frame-type main body 1, the pad strip 6 at the bottom of the oil tank 2 can form a "buffer and isolation layer" between the oil tank 2 and the lower frame 12. On the one hand, it avoids direct contact between the bottom of the oil tank 2 and the metal surface of the lower frame 12, reducing electrochemical corrosion caused by material differences (such as different metals) or environmental factors (such as moisture and corrosive media), and protecting the bottom of the oil tank 2 and the frame structure. On the other hand, when the oil tank 2 stores oil and generates a weight load, the pad strip 6 can evenly transfer the load to the lower frame 12, and then distribute it to the ground through the support column 13, avoiding structural damage caused by localized stress concentration at the bottom of the oil tank 2.

[0039] To further explain, an oil-water treatment device is installed in the oil tank 2, and the oil-water treatment device includes multiple siphon pipes 7; Multiple siphon pipes 7 are fixedly installed on the inner side wall of the oil tank 2. The inlet of the siphon pipe 7 is lower than the normal oil level of the oil tank 2, and the outlet of the siphon pipe 7 extends to the outside of the oil tank 2.

[0040] Multiple siphon pipes 7 are fixedly installed on the inner sidewall of the oil tank 2. The installation position is precisely designed—the inlet of the siphon pipe 7 is lower than the normal oil level in the oil tank 2, and the outlet extends to the outside of the oil tank 2. Due to the density difference between oil and water (water is denser than oil), the water accumulated in the oil tank 2 will settle to the bottom of the oil tank 2, while the oily substances will float on the top. When the water level in the oil tank 2 rises to the height of the inlet of the siphon pipe 7, based on the siphon principle, the water will automatically enter the siphon pipe 7 and be discharged from the outlet extending to the outside of the oil tank 2 through the guiding effect of the siphon pipe 7. At the same time, because the inlet is lower than the normal oil level but higher than the bottom of the tank, oily substances are prevented from entering the siphon pipe 7 with the water, achieving the oil-water separation effect of "only draining water, not draining oil", ensuring the purity of the oil in the oil tank 2.

[0041] Furthermore, during the operation of a medium-voltage substation, oil tank 2 may continuously generate moisture due to environmental factors (such as rainwater infiltration and oil condensation). The siphon pipe 7 achieves "passive continuous drainage" through the siphon effect, automatically removing newly added moisture from oil tank 2 without the need for additional power equipment (such as a water pump), thus preventing long-term moisture accumulation. This process not only prevents moisture from mixing with oil and affecting oil performance but also prevents moisture from corroding the external structure of oil tank 2 (such as the bottom pad 6 and outer reinforcing ribs 5), extending the service life of oil tank 2 and synergizing with the goal of "reducing maintenance costs" in frame-type oil tanks.

[0042] To further explain, the frame-type main body 1 is made of high-strength lightweight steel.

[0043] Because high-strength lightweight steel is not only low in density and light in weight, but also possesses high tensile and bending strength, when the frame structure 1, including the upper frame 11, lower frame 12, and support columns 13, is made of this material, compared to the heavy structure of traditional concrete oil tanks, it can directly bear the weight of the oil tank 2, the oil load, and the additional weight of related equipment in the substation through its own material properties. Furthermore, in the scenario of "multiple oil tanks 2 stacked for sea transport export," the weight of the upper oil tank 2 is transferred to the transport vehicle through the lower frame structure 1. The structural stability of the high-strength lightweight steel can prevent deformation or breakage of the frame, ensuring structural safety during stacked transport.

[0044] Furthermore, the high-strength lightweight steel is highly machinable and can be cut and welded in a factory to produce rectangular tubes 111 and short square tubes 112 of preset dimensions, ensuring that the upper frame 11 and the lower frame 12 have consistent structures and interchangeable components, thus solving the problem of "inconsistent standards in traditional concrete oil tanks" in the background technology. At the same time, the corrosion resistance of this material (which can be enhanced through processes such as surface galvanizing and spraying) can improve the anti-aging ability of the frame-type main body 1 in the outdoor substation environment, forming a synergistic protection with the bottom pad 6 and the outer reinforcing ribs 5 of the oil tank 2, extending the service life of the entire oil tank 2 system without compromising the core advantage of the frame-type oil tank of "easy daily maintenance".

[0045] like Figure 3 As shown, a medium-voltage substation includes a first voltage cabinet 10, a medium-voltage transformer box 20, and a second voltage cabinet 30. The first voltage cabinet 10, the medium-voltage transformer box 20, and the second voltage cabinet 30 are installed in a frame-type oil tank 40 as described above. The medium-voltage transformer box 20 is installed above the oil tank 2, and the first voltage cabinet 10 and the second voltage cabinet 30 are respectively installed above the hollow sub-space 3. The hollow sub-space 3 is used for the cables of the first voltage cabinet 10 and the cables of the second voltage cabinet 30 to pass through.

[0046] Specifically, the core equipment of the substation, namely the first voltage cabinet 10, the medium-voltage transformer box 20, and the second voltage cabinet 30, are integrated and installed with the frame-type oil bath. A complete workflow is formed around the coordinated operation of equipment, efficient use of space, and cable wiring adaptation, as detailed below: The first voltage cabinet 10, the medium-voltage transformer box 20, and the second voltage cabinet 30 of the substation are all installed on the frame-type oil bath as described above, and their installation positions are precisely adapted to the structure of the oil bath 2: the medium-voltage transformer box 20 is directly installed above the oil bath 2, utilizing the open space above the oil bath 2 for stable placement, while the oil bath 2 can also provide protection for the area below the medium-voltage transformer box 20; the first voltage cabinet 10 and the second voltage cabinet 30 are respectively installed above the two hollow sub-spaces 3 formed by the frame of the oil bath 2, so that the equipment layout corresponds to the hollow structure of the oil bath 2. This installation method avoids the equipment occupying additional ground space, and the frame of the oil bath 2 provides a unified and stable load-bearing foundation for the equipment, ensuring that the equipment is not easily displaced due to uneven ground or external vibrations during operation.

[0047] Furthermore, since the first voltage cabinet 10 and the second voltage cabinet 30 are installed above the hollow sub-space 3, their connecting cables (such as the low-voltage cable of the first voltage cabinet 10 and the medium-voltage cable of the second voltage cabinet 30) can be directly passed down from the bottom of the equipment into the hollow sub-space 3, achieving concealed cable wiring through the hollow sub-space 3. This wiring method eliminates the need to excavate cable trenches separately on the ground or make additional holes in the main body of the oil tank 2, avoiding cable exposure to environmental damage and simplifying the cable connection process. At the same time, it ensures that the cable wiring does not interfere with the oil storage function of the oil tank 2 and the drainage function of components such as the siphon pipe 7, achieving coordinated adaptation of "equipment installation - cable wiring - oil tank 2 function".

[0048] During substation operation, the second voltage cabinet 30 receives external low-voltage power and transmits it to the medium-voltage transformer box 20 for voltage boosting. The medium-voltage transformer box 20 then raises the low-voltage power to medium-voltage power (such as 10kV, 20kV, 33kV, etc.) before transmitting it to the first voltage cabinet 10, which then transmits it to the medium-voltage line or overhead line. In this process, the frame-type oil tank 40 not only provides a unified support platform for all core equipment, but its open subspace 3 also ensures the safety and smoothness of the power transmission path (cables). Simultaneously, the oil tank 2's oil storage function meets the oil storage requirements of the medium-voltage transformer box 20 (oil-immersed transformer), and the siphon pipe 7 within the oil tank 2 can promptly drain accumulated water, forming a complete operating system of "power transmission - equipment support - oil protection".

[0049] The technical principles of the present invention have been described above with reference to specific embodiments. These descriptions are merely for explaining the principles of the invention and should not be construed as limiting the scope of protection of the invention in any way. Based on this explanation, those skilled in the art can readily conceive of other specific embodiments of the invention without inventive effort, and these equivalent variations or substitutions are all included within the scope defined by the claims of this application.

Claims

1. A frame-type oil tank, characterized in that, It includes a frame structure (1) and an oil tank (2); The frame-type main body (1) includes an upper frame (11) and a lower frame (12), both of which are square frames; The upper frame (11) is fixed above the lower frame (12) by four support columns (13). The four support columns (13) are located at the four corners of the upper frame (11) and the lower frame (12), and the upper frame (11), the lower frame (12) and the four support columns (13) enclose a hollow space. The oil tank (2) is installed in the middle of the hollow space and divides the hollow space into two hollow sub-spaces (3).

2. The frame-type oil tank according to claim 1, characterized in that, The upper frame (11) and the lower frame (12) have the same structure. Both the upper frame (11) and the lower frame (12) include two rectangular tubes (111) and two short rectangular tubes (112). The two rectangular tubes (111) and the two short square tubes (112) are welded together in sequence to form the square frame; The four support columns (13) are respectively welded to the four corners of the two square frames; Corner protectors (8) are provided at the four corners of both square frames.

3. A frame-type oil tank according to claim 1, characterized in that, The frame-type main body (1) also includes a plurality of grounding seats (4), which are installed on the outer periphery of the lower frame (12).

4. A frame-type oil tank according to claim 1, characterized in that, The outer periphery of the oil tank (2) is fixed with multiple reinforcing ribs (5).

5. A frame-type oil tank according to claim 1, characterized in that, A pad (6) is provided at the bottom of the oil tank (2).

6. A frame-type oil tank according to claim 1, characterized in that, The oil tank (2) is equipped with an oil-water treatment device, which includes multiple siphon pipes (7). Multiple siphon pipes (7) are fixedly installed on the inner side wall of the oil tank (2). The inlet of the siphon pipe (7) is lower than the normal oil level of the oil tank (2), and the outlet of the siphon pipe (7) extends to the outside of the oil tank (2).

7. A frame-type oil tank according to claim 1, characterized in that, The frame structure (1) is made of high-strength lightweight steel.

8. A medium-voltage substation, characterized in that, It includes a first voltage cabinet (10), a medium-voltage transformer box (20), and a second voltage cabinet (30), wherein the first voltage cabinet (10), the medium-voltage transformer box (20), and the second voltage cabinet (30) are installed in a frame-type oil tank (40) as described in any one of claims 1-7; The medium-voltage transformer box (20) is installed above the oil tank (2), and the first voltage cabinet (10) and the second voltage cabinet (30) are respectively installed above the hollow subspace (3). The hollow subspace (3) is used for the cables of the first voltage cabinet (10) and the cables of the second voltage cabinet (30) to pass through.

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