Transformer oil tank pressure relief explosion-proof method

Abstract

The invention belongs to the field of transformers, and relates to a transformer oil tank pressure-relief explosion-proof method, a flange connecting mechanism is arranged on a transformer oil tank body, a pressure-relief explosion-proof structure is installed on the flange connecting mechanism in a sealed mode, and the pressure-relief explosion-proof structure comprises a pressure-relief explosion-proof structure shell, a metal corrugated telescopic cylinder upper cover and a metal corrugated telescopic cylinder. An upper cover of the metal corrugated telescopic cylinder is welded to the upper portion of the metal corrugated telescopic cylinder, the lower portion of the metal corrugated telescopic cylinder is welded to the first mounting flange plate, and the pressure relief anti-explosion structure shell covers the upper cover of the metal corrugated telescopic cylinder and the metal corrugated telescopic cylinder in a non-contact mode. When the internal pressure of the transformer oil tank body is sharply increased, the metal corrugated telescopic cylinder automatically expands, gas is concentrated in the metal corrugated telescopic cylinder, a transformer body and a discharge point are soaked by transformer cold oil, and cold oil arc extinguishing insulation is achieved. Pressure in the oil tank is absorbed through automatic stretching and retracting of the metal corrugated telescopic cylinder, and destructive damage caused by the internal pressure to an oil tank shell under the fault condition is avoided.

Description

Technical Field

[0001] The present invention belongs to the technical field of transformers, especially the technical field of ultra-high voltage and above transformers, and specifically relates to a method for relieving pressure and preventing explosion of a transformer oil tank. Background Art

[0002] A transformer is an important device in the power transmission and transformation network. Its main insulation and cooling medium is mineral oil (transformer oil). When a discharge fault occurs inside the transformer, a very large arc energy will be generated. Especially for ultra-high voltage transformers, the generated arc energy is even more huge. The arc with huge energy will cause a large amount of gas to be generated in the transformer oil, causing the pressure inside the oil tank with a closed structure to rise sharply. When the pressure exceeds the bearing capacity of the oil tank, the oil tank will rupture, and in severe cases, it may lead to a transformer explosion accident.

[0003] Patent publication number CN219778656U, with the name of an explosion-proof reinforcement structure for a transformer oil tank and a transformer oil tank. The explosion-proof reinforcement structure includes a tank wall, the top of the tank wall is connected to the tank rim of the transformer oil tank, and the bottom is connected to the bottom plate of the transformer oil tank; a hoop is arranged around one end of the tank wall close to the tank rim; a reinforcing plate is arranged at the corner; the reinforcing plate is attached to the tank wall and perpendicular to the tank wall. The hoop is arranged at the position of the transformer oil tank close to the tank rim, and a reinforcing plate is arranged at the corner of the transformer oil tank. Although this structure effectively strengthens the strength of the weak position of the oil tank, however, when the pressure inside the transformer oil tank increases sharply instantaneously, an internal pressure impact will be exerted on the oil tank, and tearing or even explosion may occur at the existing weak points of the oil tank. At the same time, the internal pressure impact will cause the local mechanical strength of the oil tank to decrease, thus forming new structural weak points. In short, the technical solutions disclosed in the above patents cannot effectively reduce the pressure inside the oil tank, nor can they effectively solve the technical problem of possible explosion of the oil tank. Summary of the Invention

[0004] Aiming at the current problem of deflagration or even explosion caused by transformer discharge faults, the present invention designs a metal corrugated expansion device on the transformer oil tank, so that when the pressure inside the transformer oil tank rises sharply due to discharge, the corrugated expansion device can reduce the pressure inside the transformer oil tank through expansion, avoiding the explosion of the oil tank.

[0005] In order to solve the above technical problems, the technical solution adopted by the present invention is: A method for relieving pressure and preventing explosion of a transformer oil tank, which uses cold oil for arc extinguishing and insulation, includes the following steps: Set more than one flange connection mechanism on the transformer oil tank body. The flange connection mechanism is set on the top wall or side wall of the transformer oil tank body, and at least one of the flange connection mechanisms is set on the top wall of the transformer oil tank body. The flange connection mechanism is communicated with the inside of the transformer oil tank body; The pressure relief and explosion-proof structure is fixedly installed on the flange connection mechanism in a sealed manner. The pressure relief and explosion-proof structure includes a pressure relief and explosion-proof structure housing, an upper cover of a metal corrugated expansion joint, and a metal corrugated expansion joint. The upper cover of the metal corrugated expansion joint is welded to the upper part of the metal corrugated expansion joint, and the lower part of the metal corrugated expansion joint is welded to the upper surface of a first mounting flange. An opening is provided in the middle of the first mounting flange, and the size of the opening is smaller than the inner diameter of the metal corrugated expansion joint. The pressure relief and explosion-proof structure housing is buckled over the upper cover of the metal corrugated expansion joint and the metal corrugated expansion joint without contact, and a spacing for the elongation of the metal corrugated expansion joint is reserved between the pressure relief and explosion-proof structure housing and the upper cover of the metal corrugated expansion joint. The lower part of the pressure relief and explosion-proof structure housing is connected and installed on the upper surface of the first mounting flange by bolts. When a discharge point appears inside the transformer tank body and an explosion and combustion fault occurs, resulting in a sharp increase in the internal pressure, the metal corrugated expansion joint automatically elongates and expands. The gas finally accumulates in the metal corrugated expansion joint, and the transformer core continues to be immersed in the cold transformer oil. At the same time, the discharge point is immersed in the cold transformer oil, achieving arc extinguishing and insulation with cold oil.

[0006] Preferably, a plurality of fixing nuts are evenly welded and arranged at the edge position of the upper surface of the first mounting flange. Fixing perforations corresponding to the fixing nuts one by one are provided at the edge position of the upper cover of the metal corrugated expansion joint. When the transformer is transported or a positive and negative pressure test is carried out, the lower end of the fixing screw is passed through the fixing perforation on the upper cover of the metal corrugated expansion joint, and the lower end of the fixing screw is tightened with the upper end of the fixing nut to fix the metal corrugated expansion joint. When the transformer is officially put into operation, the fixing screw is screwed out of the fixing nut (4) so that the metal corrugated expansion joint can automatically expand and contract.

[0007] Preferably, the flange connection mechanism includes a second mounting flange, which is welded to the transformer tank body. An opening is provided in the middle of the second mounting flange. The opening of the second mounting flange has the same shape and size as the opening of the first mounting flange. The first mounting flange and the second mounting flange are fixedly and hermetically connected by bolts and gaskets. An opening is provided at a position corresponding to the opening of the second mounting flange on the outer shell of the transformer tank body, and the opening has the same shape and size as the opening of the second mounting flange.

[0008] Preferably, the shape of the first mounting flange and the shape of the opening are rectangular, square, oval or circular.

[0009] The present invention has the following advantages: When an internal fault occurs in the transformer, causing a sharp increase in the internal pressure, the present invention can achieve the automatic elongation of the metal corrugated expansion cylinder of this structure, absorb part of the pressure in the oil tank, reduce the destructive damage caused by the internal pressure to the oil tank shell. This structure can also collect the gas formed by the transformer fault, prevent the transformer body from being exposed to the gas, reduce the insulation performance of the transformer body, and further evolve the accident into more discharge faults. This structure can effectively reduce the damage of the oil tank shell and avoid major dangerous accidents such as the further deterioration or even explosion of the discharge fault. The present invention utilizes the principle that the pressure relief and explosion-proof structure can expand flexibly and relieve pressure quickly, and the gas generated by the internal discharge of the transformer moves upward into the cavity of the pressure relief and explosion-proof structure. The cold oil can extinguish the arc and insulate, striving to effectively prevent the further deterioration of the internal fault of the transformer within a very short time, providing sufficient time for the pressure release of the transformer and various on-line monitoring reaction alarms, and reducing the possibility of the occurrence of transformer explosion accidents. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] The drawings are used to provide a further understanding of the present invention, and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention, and do not constitute a limitation to the present invention. In the drawings: Figure 1 is the front view of the transformer oil tank according to the embodiment of the present invention; Figure 2 is the top view of the transformer oil tank according to the embodiment of the present invention; Figure 3 is the schematic diagram of the principle of the transformer oil tank pressure relief and explosion-proof method according to the embodiment of the present invention; Among them, 1 - pressure relief and explosion-proof structure housing, 2 - upper cover of the metal corrugated expansion cylinder, 3 - metal corrugated expansion cylinder, 4 - fixing nut, 5 - mounting flange one, 6 - mounting flange two, 7 - transformer oil tank body. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0011] The technical solutions of the present invention will be clearly and completely described below in conjunction with the drawings. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments.

[0012] Figure 1 、 Figure 2 and Figure 3 include the internal perspective effect of the pressure relief and explosion-proof structure housing 1. Combining with Figure 1 、 Figure 2 and Figure 3 shown, a transformer oil tank pressure relief method provided by the embodiment of the present invention uses cold oil to extinguish the arc and insulate, and includes the following steps: One or more flange connection mechanisms are provided on the main body 7 of the transformer oil tank. The flange connection mechanisms are provided on the top wall or the side wall of the main body 7 of the transformer oil tank, and at least one of the flange connection mechanisms is provided on the top wall of the main body 7 of the transformer oil tank. The flange connection mechanism is in communication with the inside of the main body 7 of the transformer oil tank. The flange connection mechanism includes a second mounting flange 6, and the second mounting flange 6 is welded to the main body 7 of the transformer oil tank. An opening two is provided in the middle of the second mounting flange 6. The shape and size of the opening two of the second mounting flange 6 are the same as those of the opening one of the first mounting flange 5. The first mounting flange 5 and the second mounting flange 6 are fixedly and sealedly connected by bolts and gaskets. An opening three is provided at a position corresponding to the opening two on the outer shell of the main body 7 of the transformer oil tank. The shape and size of the opening three are the same as those of the opening two.

[0013] The pressure relief and explosion-proof structure is fixedly and sealedly installed on the flange connection mechanism. The pressure relief and explosion-proof structure includes a pressure relief and explosion-proof structure housing 1, an upper cover 2 of a metal corrugated expansion cylinder, and a metal corrugated expansion cylinder 3. The pressure relief and explosion-proof structure housing 1 is made of a rigid material. The lower surface of the upper cover 2 of the metal corrugated expansion cylinder is fixedly connected to the upper part of the metal corrugated expansion cylinder 3 by welding. The lower part of the metal corrugated expansion cylinder 3 is fixedly connected to the upper surface of the first mounting flange 5 by welding. An opening one is provided in the middle of the first mounting flange 5. The size of the opening one is slightly smaller than the inner diameter of the metal corrugated expansion cylinder 3. The pressure relief and explosion-proof structure housing 1 is buckled over the upper cover 2 of the metal corrugated expansion cylinder and the metal corrugated expansion cylinder 3 without contact. A spacing for the elongation of the metal corrugated expansion cylinder 3 is reserved between the pressure relief and explosion-proof structure housing 1 and the upper cover 2 of the metal corrugated expansion cylinder. This spacing needs to be able to meet the maximum automatic expansion and contraction stroke of the metal corrugated expansion cylinder 3. The lower part of the pressure relief and explosion-proof structure housing 1 is detachably connected to the upper surface of the first mounting flange 5 by bolts. The pressure relief and explosion-proof structure housing 1 can play a role in dust prevention and protection for the internal structural parts such as the metal corrugated expansion cylinder 3 and the upper cover 2 of the metal corrugated expansion cylinder located inside it.

[0014] A number of fixing nuts 4 are evenly distributed and welded at the edge position of the upper surface of the first mounting flange 5. Fixing perforations corresponding to the fixing nuts 4 one by one are provided at the edge position of the upper cover 2 of the metal corrugated expansion cylinder. When the transformer is transported or a positive and negative pressure test is carried out, in order to prevent the metal corrugated expansion cylinder 3 from being deformed or damaged by force, the lower end of the fixing screw is passed through the fixing perforation on the upper cover 2 of the metal corrugated expansion cylinder, and the lower end of the fixing screw is tightened with the upper end of the fixing nut 4 to fix the metal corrugated expansion cylinder 3. When the transformer is officially put into operation, the fixing screw is screwed out of the fixing nut 4 so that the metal corrugated expansion cylinder 3 can expand and contract automatically.

[0015] Set the thickness and weight of the upper cover 2 of the metal corrugated expansion cylinder according to the internal oil pressure of the transformer. If the weight of the existing upper cover 2 of the metal corrugated expansion cylinder cannot meet the requirements, counterweights can also be added to the upper cover 2 of the metal corrugated expansion cylinder.

[0016] The pressure relief and explosion-proof method of the transformer oil tank in the embodiment of the present invention has the following pressure relief principle: A retractable metal corrugated expansion cylinder 3 is provided on the upper part or side of the transformer oil tank body 7. The upper cover 2 of the metal corrugated expansion cylinder in the upper part is set with different weights according to the internal oil pressure of the transformer, so that the upper cover 2 of the metal corrugated expansion cylinder remains in the low position (initial state). When there is a discharge point inside the transformer oil tank body 7 and an explosion and combustion fault occurs, resulting in a sharp increase in the internal pressure of the transformer oil tank body 7, the internal pressure overcomes the gravity of the upper cover 2 of the metal corrugated expansion cylinder, causing the metal corrugated expansion cylinder 3 to elongate, increasing the volume of the transformer oil tank, reducing the damage caused by the internal pressure to the transformer oil tank. After the metal corrugated expansion cylinder 3 elongates, its height increases, and the gas generated due to the fault inside the oil tank automatically floats upward, and finally the gas is concentrated in the metal corrugated expansion cylinder 3. In this way, the transformer core can continue to be soaked in the cold transformer oil, and at this time, due to the concentration of the fault gas in the metal corrugated expansion cylinder 3, the low-temperature cold transformer oil inside the conservator can be supplemented to the discharge position that was not soaked before, cooling the discharge position, improving the insulation performance of the transformer core, avoiding the further deterioration of accidents such as discharge, and reducing the occurrence of large-scale power accidents such as the explosion of the transformer oil tank by installing the metal corrugated expansion cylinder 3.

[0017] Although Figure 1 、 2 The pressure relief and explosion-proof structure shown in Figure 3 is rectangular. However, the above pressure relief and explosion-proof structure is not limited to rectangular, square, oval or circular structures, etc., and can be flexibly designed according to the space at the cover of the transformer oil tank body 7. Multiple such pressure relief and explosion-proof structures can also be installed on one transformer oil tank body 7, and this pressure relief and explosion-proof structure can also be installed at positions such as the side wall of the transformer oil tank body 7.

[0018] In the embodiment of the present invention, the technical features not described in detail are all prior art or conventional technical means, and will not be elaborated here.

[0019] Finally, it should be noted that: The above embodiments are only specific implementation manners of the present invention, used to illustrate the technical solutions of the present invention, rather than limiting it. The protection scope of the present invention is not limited thereto. Those skilled in the art should understand that: Any person skilled in the art within the technical scope disclosed by the present invention can modify the technical solutions recorded in the foregoing embodiments, or can easily think of changes, or perform equivalent replacements on some of the technical features; and these modifications, changes or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be covered within the protection scope of the present invention.

Claims

1. A transformer oil tank pressure relief explosion-proof method, using cold oil for arc extinguishing insulation, characterized in that: The following steps are involved: One or more flange connection mechanisms are arranged on the transformer oil tank body (7), the flange connection mechanisms being arranged on the top wall or the side wall of the transformer oil tank body (7), and at least one flange connection mechanism is arranged on the top wall of the transformer oil tank body (7), and the flange connection mechanism is in communication with the interior of the transformer oil tank body (7); The pressure relief and explosion-proof structure is sealed and fixedly mounted on the flange connection mechanism, wherein the pressure relief and explosion-proof structure comprises a pressure relief and explosion-proof structure housing (1), a metal corrugated telescopic cylinder upper cover (2) and a metal corrugated telescopic cylinder (3), wherein the metal corrugated telescopic cylinder upper cover (2) is welded to the upper part of the metal corrugated telescopic cylinder (3), and the lower part of the metal corrugated telescopic cylinder (3) is welded to the upper surface of the mounting flange plate (5), and an opening (1) is opened in the middle of the mounting flange plate (5), and the size of the opening (1) is smaller than the inner diameter of the metal corrugated telescopic cylinder (3); the pressure relief and explosion-proof structure housing (1) is non-contactly buckled on the metal corrugated telescopic cylinder upper cover (2) and the metal corrugated telescopic cylinder (3), and a space for the metal corrugated telescopic cylinder (3) to extend is reserved between the pressure relief and explosion-proof structure housing (1) and the metal corrugated telescopic cylinder upper cover (2), and the lower part of the pressure relief and explosion-proof structure housing (1) is mounted on the upper surface of the mounting flange plate (5) by bolt connection; When a discharge point appears inside the transformer oil tank body (7) and an explosion fault occurs, causing the internal pressure to increase sharply, the metal corrugated telescopic cylinder (3) automatically stretches and expands, and the gas is finally concentrated in the metal corrugated telescopic cylinder (3), and the transformer body continues to be immersed in the transformer cold oil. At the same time, the discharge point is immersed in the transformer cold oil, thereby achieving cold oil arc extinguishing insulation.

2. A transformer oil tank pressure relief and explosion-proof method according to claim 1, characterized in that: A plurality of fixing nuts (4) are evenly welded and arranged at the edge of the upper surface of the mounting flange (5), and fixing through holes corresponding to the fixing nuts (4) are provided at the edge of the upper cover (2) of the metal corrugated telescopic cylinder; when the transformer is transported or a positive or negative pressure test is performed, the lower end of the fixing screw is passed through the fixing through hole on the upper cover (2) of the metal corrugated telescopic cylinder, and the lower end of the fixing screw is tightened with the upper end of the fixing nut (4), thereby fixing the metal corrugated telescopic cylinder (3); when the transformer is officially put into operation, the fixing screw is unscrewed from the fixing nut (4), so that the metal corrugated telescopic cylinder (3) can be automatically extended and retracted.

3. A transformer oil tank pressure relief and explosion-proof method according to claim 2, characterized in that: The flange connection mechanism comprises a second mounting flange (6), the second mounting flange (6) being welded to the transformer oil tank body (7), a second opening being provided in the middle of the second mounting flange (6), the second opening of the second mounting flange (6) being of the same shape and size as the first opening of the first mounting flange (5), the first mounting flange (5) being fixedly and sealedly connected to the second mounting flange (6) by bolts and a sealing gasket; a third opening being provided at a position corresponding to the second opening on the outer shell of the transformer oil tank body (7), the third opening being of the same shape and size as the second opening.

4. A transformer oil tank pressure relief and explosion-proof method according to claim 2, characterized in that: The shape of the mounting flange 1 (5) and the shape of the opening 1 are rectangular, square, elliptical or circular.

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