A new transformer bushing structure with flame retardant and explosion-proof properties

Abstract

The present invention relates to a novel transformer bushing structure with flame retardant and explosion-proof properties, wherein a rubber-impregnated paper main insulation layer is sleeved onto a current-carrying conductor, a silicone rubber composite insulation jacket is sleeved onto the upper outer portion of the rubber-impregnated paper main insulation layer, and the space between the upper portion of the rubber-impregnated paper main insulation layer and the silicone rubber composite insulation jacket is filled with an inert gas. The current-carrying conductor is provided with a head terminal at its upper end and a tail terminal at its lower end. The upper end of the silicone rubber composite insulation jacket is provided with an upper sleeve flange, a head cover plate, and a head sealing plate. The upper sleeve flange is sleeved onto the silicone rubber composite insulation jacket, the head cover plate is sleeved onto the current-carrying conductor and is fixedly connected to the upper sleeve flange on its lower side. A head radial sealing assembly is provided between the upper sleeve flange and the head cover plate. The head sealing plate is sleeved onto the current-carrying conductor and is fixedly connected to the upper side of the head cover plate. A head axial sealing and electrical connection assembly are provided between the head sealing plate, the head cover plate, and the current-carrying conductor. The present invention has flame retardant and explosion-proof properties and can reduce hazards in the event of extreme faults.

Description

Technical Field

[0001] The invention relates to the field of transformers, in particular to a novel transformer bushing structure with flame retardant and explosion-proof properties. Background Art

[0002] Power transformers are crucial core equipment in power plants and substations. Their safety performance directly affects the normal operation of the line. Bushings, as key components of transformers, are mainly used to lead the high and low voltage leads inside the transformer to the outside of the oil tank. They not only insulate the leads from the ground but also have the function of fixing the leads. At the same time, the transformer bushing is one of the current-carrying components of the transformer and must bear long-term load current during transformer operation.

[0003] Traditional oil-paper capacitor bushings are highly susceptible to serious accidents in extreme fault conditions. For example, because both insulating oil and paper are flammable, abnormal discharges within the bushing or prolonged overheating can easily cause the insulating oil to decompose and produce gas, leading to increased internal pressure and even explosions and fires, seriously threatening the safety of surrounding equipment and personnel. Since the transformer itself requires transformer oil for insulation and cooling, a bushing explosion or fire would inevitably affect the oil inside the transformer, causing even more serious problems and compromising the safe operation of the transformer and the transmission line.

[0004] In summary, the improvement of flame retardant and explosion-proof performance of transformer bushing is of great significance. Since the bushing needs to meet the requirements of long-term electrical performance, thermal performance and mechanical performance, the improvement of flame retardant and explosion-proof performance of the bushing also needs to be analyzed and studied from multiple dimensions. Summary of the Invention

[0005] The purpose of the present invention is to provide a novel transformer bushing structure with flame retardant and explosion-proof properties, which has flame retardant and explosion-proof properties and can reduce the degree of harm in the event of extreme faults.

[0006] The object of the present invention is achieved through the following technical solutions:

[0007] A new type of transformer bushing structure with flame retardant and explosion-proof properties, comprising a rubber-impregnated paper main insulation layer, a current-carrying conductor and a silicone rubber composite insulation jacket, wherein the rubber-impregnated paper main insulation layer is sleeved on the outside of the current-carrying conductor, the silicone rubber composite insulation jacket is sleeved on the outside of the upper part of the rubber-impregnated paper main insulation layer, and a gap filled with inert gas is provided between the upper part of the rubber-impregnated paper main insulation layer and the silicone rubber composite insulation jacket, the current-carrying conductor is provided with a head terminal at the upper end and a tail terminal at the lower end, the upper end of the silicone rubber composite insulation jacket is provided with an upper sleeve flange, a head cover and a head sealing plate, wherein the upper sleeve flange is sleeved on the silicone rubber composite insulation jacket, the head cover is sleeved on the current-carrying conductor and the lower side is fixedly connected to the upper sleeve flange, a head radial sealing assembly is provided between the upper sleeve flange and the head cover, the head sealing plate is sleeved on the current-carrying conductor and fixedly connected to the upper side of the head cover, and a head axial sealing and electrical connection assembly are provided between the head sealing plate, the head cover and the current-carrying conductor.

[0008] The head axial sealing and electrical connection assembly includes an electrical connection element and multiple sealing elements, wherein the first sealing element and the electrical connection element are arranged between the head cover and the current-carrying conductor, the second sealing element is arranged between the head cover, the head sealing plate and the current-carrying conductor, the third sealing element is arranged between the head sealing plate and the current-carrying conductor, and the fourth sealing element is arranged between the head sealing plate and the head cover.

[0009] The upper sleeve flange is fixedly connected to the lower side of the head cover plate, and the head radial sealing assembly includes a fifth sealing element and a sixth sealing element, wherein the fifth sealing element is arranged between the head cover plate and the upper sleeve flange, and the sixth sealing element is arranged between the head cover plate, the upper sleeve flange and the silicone rubber composite insulating jacket.

[0010] A shielding cover is provided at the lower end of the main insulating layer of the rubber-impregnated paper, and the tail terminal is arranged in the shielding cover.

[0011] A flange tube and a mounting flange are mounted in the middle of the rubber-impregnated paper main insulation layer. A first flange is mounted on the upper end of the flange tube and a second flange is mounted on the lower end. A lower sleeve flange is mounted on the outer side of the lower end of the silicone rubber composite insulation jacket. The lower sleeve flange is fixedly connected to the first flange of the flange tube, and the second flange is fixedly connected to the mounting flange.

[0012] A protrusion is provided in the middle of the main insulating layer of the rubber-impregnated paper, and the flange cylinder is sleeved on the protrusion, and the upper end of the protrusion cooperates with the first flange stop of the flange cylinder, and the lower end cooperates with the mounting flange stop.

[0013] A first intermediate sealing element is provided between the mounting flange and the silicone rubber composite insulating jacket, a second intermediate sealing element is provided between the mounting flange and the second flange at the lower end of the flange cylinder, and a third intermediate sealing element is provided between the first flange at the upper end of the flange cylinder and the lower sleeve flange.

[0014] The mounting flange is made of non-magnetic stainless steel, the first intermediate sealing element close to the transformer is made of fluororubber, and the first intermediate sealing element close to the flange cylinder is made of EPDM rubber.

[0015] The flange cylinder is provided with a pressure relief device, which includes a connecting seat, a reverse pressure release plate, a fixed plate and a protective cover, wherein a gas channel is provided inside the connecting seat, the reverse pressure release plate is provided in the gas channel, and side plates are provided on both sides of the reverse pressure release plate and are press-fitted to the connecting seat through the fixed plate, a through hole is provided in the middle of the fixed plate, the protective cover is provided on the upper side of the connecting seat, and the fixed plate and the reverse pressure release plate are both provided in the protective cover, and an exhaust hole is provided on the protective cover.

[0016] The flange cylinder is provided with a self-sealing joint, which includes a support seat, an action contact, a limit nut and a spring, wherein a vent is provided inside the support seat, and the lower end of the action contact is supported in the vent by a spring, and a limit nut is provided at the upper end of the support seat, and the upper end of the action contact extends into the threaded hole in the middle of the limit nut, and a groove for accommodating the limit nut is provided on the upper side of the support seat, and a support seat sealing ring is provided between the limit nut and the limit groove surface at the bottom of the groove, and a contact sealing ring is provided on the action contact, and when the action contact is not subjected to external force, the contact sealing ring is against the lower end surface of the limit nut.

[0017] The advantages and positive effects of the present invention are:

[0018] 1. The main insulation layer of the rubber-impregnated paper of the present invention is made of rubber-impregnated paper oil-free insulation material, and its heat resistance level and material ignition point are higher than those of traditional oil-paper bushings. The silicone rubber composite insulation outer jacket is filled with inert gas such as SF6 or N2 instead of transformer oil, which fully ensures the overall flame retardant performance of the present invention. Since the bushing does not need to be filled with transformer oil, there will be no situation where the transformer oil decomposes and produces gas and burns due to internal discharge.

[0019] 2. The present invention uses a silicone rubber composite outer insulation sleeve instead of a traditional porcelain outer sleeve. Even in extreme cases of excessive internal pressure, this prevents explosions. Pressure is released only in the form of cracks at weak points, without explosions or splashing. Furthermore, the present invention optimizes the bushing's electric field design to reduce the maximum radial and axial field strengths. This reduction in field strength provides a higher insulation margin for the bushing, preventing partial discharge or breakdown caused by overvoltage.

[0020] 3. The upper end of the present invention is provided with a head axial seal and electrical connection component and a head radial seal component, and each sealing component can be designed with a combination of flat rings, O-rings, D-rings, etc. for sealing as needed, thereby improving the overall sealing performance of the bushing and reducing the risk of discharge failure caused by water entering the bushing due to poor sealing. In the middle part of the present invention, the protrusion of the main insulating layer of the glue-impregnated paper is embedded in the flange tube to ensure sealing.

[0021] 4. The present invention optimizes the material of the mounting flange. Conventional bushings are usually made of cast aluminum alloy, which has a melting point of approximately 600°C. However, the mounting flange of the present invention is made of non-magnetic stainless steel, which has a melting point of over 1000°C. Even if surrounding equipment or the transformer body catches fire, the transformer bushing with the new structure of the present invention will remain fixed for a longer time than the conventional bushing.

[0022] 5. Since the interior of the transformer is an oil environment, and the interior of the bushing of the present invention is an inert gas environment filled with a certain pressure, the upper and lower ends of the flange tube of the present invention are both provided with sealing elements, and the materials are different to better meet the sealing requirements.

[0023] 6. The casing of the present invention needs to be filled with an inert gas of a certain pressure. Therefore, a pressure relief device can be provided on the flange tube or the head cover as needed. When the internal gas pressure rises to a specified value, the pressure relief device will be activated to prevent the explosion caused by excessive pressure. Under normal circumstances, the actuation starting pressure of the pressure relief device is greater than the normal operating pressure of the casing and less than the maximum operating pressure allowed by the silicone rubber composite outer insulating sleeve. Therefore, the use of a pressure relief device can logically avoid damage to the outer insulating sleeve of the casing. At the same time, even if the pressure relief device fails to relieve pressure for some reason, the characteristics of the silicone rubber composite outer insulating sleeve can also ensure that the casing product does not explode. The combination of the pressure relief device and the silicone rubber composite outer insulating sleeve further improves the explosion-proof performance of the casing.

[0024] 7. The flange tube of the present invention can be provided with a self-sealing joint as needed, and can be connected to external equipment to realize the internal air vacuuming, inflation and other operations of the present invention, or can be installed with a gas pressure gauge or an air guide tube and other components to realize the gas pressure monitoring function, while also ensuring that the gas in the casing of the present invention will not leak. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a structural schematic diagram of the present invention,

[0026] Figure 2 for Figure 1 A in the enlarged view,

[0027] Figure 3 for Figure 1 The enlarged view of point B in the figure is as follows:

[0028] Figure 4 for Figure 1 The enlarged view of point C in the figure,

[0029] Figure 5 for Figure 1 The enlarged view of point D in the figure is as follows:

[0030] Figure 6 for Figure 1 The enlarged view of point E in the figure,

[0031] Figure 7 for Figure 1 The enlarged view of point F in the figure is as follows:

[0032] Figure 8 for Figure 7 A partial enlarged schematic diagram of one side of the middle structure.

[0033] Figure 9 This is a schematic diagram of the pressure relief device used in the present invention.

[0034] Figure 10 Schematic diagram of the self-sealing joint used in the present invention.

[0035] Among them, 1 is the main insulation layer of rubber-impregnated paper, 101 is the protrusion, 2 is the current-carrying conductor, 3 is the mounting flange, 4 is the silicone rubber composite insulation jacket, 5 is the inert gas, 6 is the head axial seal and electrical connection assembly, 601 is the first sealing element, 602 is the electrical connection element, 603 is the second sealing element, 604 is the third sealing element, 605 is the fourth sealing element, 7 is the head radial seal assembly, 701 is the fifth sealing element, 702 is the sixth sealing element, 8 is the head terminal, 9 is the tail terminal, 10 is the head cover, 11 is the head sealing plate, 12 is the upper sleeve flange, 13 is the flange cylinder, and 14 is the shielding cover , 15 is the third intermediate sealing element, 16 is the second intermediate sealing element, 17 is the first intermediate sealing element, 18 is the lower sleeve flange, 19 is the pressure relief device, 191 is the reverse pressure release plate, 192 is the connecting seat, 193 is the fixing plate, 194 is the protective cover, 195 is the exhaust hole, 196 is the gas channel, 20 is the self-sealing joint, 201 is the support seat, 2011 is the limiting groove surface, 2012 is the support seat flange, 202 is the action contact, 2021 is the support table, 203 is the limiting nut, 204 is the spring, 205 is the support seat sealing gasket, 206 is the contact sealing gasket, and 207 is the vent. DETAILED DESCRIPTION

[0036] The present invention will be further described below in conjunction with the accompanying drawings.

[0037] like Figures 1 to 10 As shown, the present invention comprises a main insulating layer of glue-impregnated paper 1, a current-carrying conductor 2 and a silicone rubber composite insulating jacket 4, wherein Figure 2As shown, the main insulation layer 1 of the rubber-impregnated paper is sleeved on the outside of the current-carrying conductor 2, and the silicone rubber composite insulation jacket 4 is sleeved on the outside of the upper part of the main insulation layer 1 of the rubber-impregnated paper, and a gap filled with inert gas 5 is provided between the upper part of the main insulation layer 1 of the rubber-impregnated paper and the silicone rubber composite insulation jacket 4. Figure 1 As shown, the lower part of the main insulation layer 1 of the impregnated paper is arranged outside the silicone rubber composite insulation jacket 4, and the upper end of the current-carrying conductor 2 is provided with a head terminal 8 and the lower end is provided with a tail terminal 9. Figure 1 and Figures 3-4 As shown, the upper end of the silicone rubber composite insulating jacket 4 is provided with an upper sleeve flange 12, a head cover plate 10 and a head sealing plate 11, wherein Figure 4 As shown, the upper sleeve flange 12 is sleeved on the outside of the silicone rubber composite insulating jacket 4, the head cover 10 is sleeved on the current-carrying conductor 2 and the lower side is fixedly connected to the upper sleeve flange 12, and a head radial sealing component 7 is provided between the upper sleeve flange 12 and the head cover 10, as shown in FIG. Figure 3 As shown, the head sealing plate 11 is mounted on the current-carrying conductor 2 and fixedly connected to the upper side of the head cover plate 10, and a head axial seal and electrical connection assembly 6 is provided between the head sealing plate 11, the head cover plate 10 and the current-carrying conductor 2. The main insulating layer 1 of the rubber-impregnated paper of the present invention is made of rubber-impregnated paper oil-free insulating material, which is a well-known technology in the field. Its heat resistance level and material ignition point are higher than those of traditional oil-paper bushings, and the silicone rubber composite insulating jacket 4 is filled with inert gases such as SF6 or N2 instead of transformer oil, which further improves the overall flame retardant performance. In addition, the silicone rubber composite insulating jacket 4 adopts a silicone rubber composite outer insulating jacket with higher mechanical strength, better toughness and no splashing, which greatly improves the explosion-proof performance of the bushing. Figure 2 As shown, in this embodiment, long sheds and short sheds are alternately provided on the outside of the silicone rubber composite insulating jacket 4. In addition, the present invention adopts pure copper or oxygen-free high-conductivity copper with better current-carrying performance and thermal conductivity as the current-carrying conductor 2 to fundamentally reduce the temperature rise of the bushing and effectively solve the problem of thermal breakdown of the main insulation of the bushing.

[0038] like Figure 3As shown, in this embodiment, the head sealing plate 11 is fixedly connected to the upper side of the head cover plate 10 by screws, and the head axial sealing and electrical connection assembly 6 includes a first sealing element 601, an electrical connection element 602, a second sealing element 603, a third sealing element 604 and a fourth sealing element 605, wherein the first sealing element 601 and the electrical connection element 602 are arranged between the head cover plate 10 and the current-carrying conductor 2. In this embodiment, the electrical connection element 602 is a metal spring wire. The present invention uses this element to achieve equipotential between adjacent head cover plates 10 and current-carrying conductors 2. The second sealing element 603 is arranged between the head cover plate 10, the head sealing plate 11 and the current-carrying conductor 2, the third sealing element 604 is arranged between the head sealing plate 11 and the current-carrying conductor 2, and a fourth sealing element 605 is provided between the head sealing plate 11 and the head cover plate 10. Each sealing element can be designed for combined sealing using a flat ring, an O-ring, a D-ring, etc. as needed.

[0039] like Figure 4 As shown, the upper end of the upper sleeve flange 12 is fixedly connected to the lower side of the head cover plate 10 by screws. In this embodiment, the head radial seal assembly 7 includes a fifth sealing element 701 and a sixth sealing element 702, wherein the fifth sealing element 701 is provided between the head cover plate 10 and the upper sleeve flange 12, and the sixth sealing element 702 is provided between the head cover plate 10, the upper sleeve flange 12 and the silicone rubber composite insulating jacket 4. Each sealing element can be designed as a combination of flat rings, O-rings, D-rings, etc. as needed.

[0040] like Figures 5-6 As shown, the cross-sections of the head terminal 8 and the tail terminal 9 are both convex structures, with the thin-diameter ends serving as connecting ends and the thick-diameter ends being welded and fixedly connected to the corresponding ends of the current-carrying conductors 2 .

[0041] like Figure 7 As shown, a flange cylinder 13 and a mounting flange 3 are mounted in the middle of the rubber-impregnated paper main insulating layer 1 , and the upper end of the flange cylinder 13 is fixedly connected to the lower end of the silicone rubber composite insulating jacket 4 , and the lower end of the flange cylinder 13 is fixedly connected to the mounting flange 3 .

[0042] like Figure 8 As shown, the flange cylinder 13 is provided with a first flange at the upper end and a second flange at the lower end, and the lower sleeve flange 18 is sleeved on the outer side of the lower end of the silicone rubber composite insulating jacket 4, and the lower sleeve flange 18 is bolted to the first flange of the flange cylinder 13, and the second flange is bolted to the mounting flange 3.

[0043] like Figure 8As shown, a protrusion 101 is provided in the middle of the main insulating layer 1 of the rubber-impregnated paper, and the flange cylinder 13 is mounted on the protrusion 101, and the upper end of the protrusion 101 cooperates with the first flange of the flange cylinder 13 as a stopper, and the lower end cooperates with the mounting flange 3 as a stopper to facilitate installation.

[0044] The flange barrel 13 and the mounting flange 3 are responsible for fixing the bushing and isolating the transformer oil environment from the bushing filler environment. Conventional bushing flanges are usually made of cast aluminum alloy with a melting point of approximately 600°C. However, the flange barrel 13 and the mounting flange 3 of the present invention are made of non-magnetic stainless steel with a melting point of over 1000°C. Even if surrounding equipment or the transformer body catches fire, the transformer bushing with the new structure of the present invention will remain fixed for a longer time than the conventional bushing.

[0045] like Figure 8 As shown, two first intermediate sealing elements 17 are provided between the mounting flange 3 and the main insulating layer 1 of the rubber-impregnated paper, two second intermediate sealing elements 16 are provided between the mounting flange 3 and the second flange at the lower end of the flange cylinder 13, and two third intermediate sealing elements 15 are provided between the first flange at the upper end of the flange cylinder 13 and the lower sleeve flange 18. Because the interior of the transformer is an oil environment, and the interior of the bushing is an inert gas environment filled with a certain pressure, a seal is provided between the mounting flange 3 and the main insulating layer 1 of the rubber-impregnated paper to prevent the inert gas at a certain pressure inside the bushing from entering the oil of the transformer and causing transformer failure, as shown in FIG. Figure 8 As shown, in this embodiment, the first intermediate sealing element 17 close to the transformer side is close to the oil environment and can be made of fluororubber with better oil resistance and high temperature resistance. The first intermediate sealing element 17 close to the flange cylinder 13 side is close to the inert gas environment and can be made of EPDM rubber with better corrosion resistance.

[0046] In addition, since the sleeve of the present invention needs to be filled with an inert gas at a certain pressure, a pressure relief device 19 can be provided on one side of the flange cylinder 13 or the head cover 10 as needed. When the internal gas pressure rises to a specified value, the pressure relief device 19 is activated to prevent an explosion caused by excessive pressure.

[0047] like Figure 9As shown, the pressure relief device 19 of the present invention includes a connecting seat 192, a reverse pressure release plate 191, a fixing plate 193 and a protective cover 194, wherein the lower end of the connecting seat 192 is provided with a connecting seat flange fixedly connected to the flange cylinder 13 or the head cover 10, and a gas channel 196 is provided inside the connecting seat 192, the reverse pressure release plate 191 is arranged in the gas channel 196, and side plates are provided on both sides of the reverse pressure release plate 191 and are press-fitted onto the connecting seat 192 through the fixing plate 193, a through hole is provided in the middle of the fixing plate 193, and the protective cover 194 is provided on the upper side of the connecting seat 192, and the fixing plate 193 and the reverse pressure release plate 191 are both provided in the protective cover 194, and the protective cover 194 is provided with an exhaust hole 195. When the internal pressure of the sleeve of the present invention exceeds the rated pressure-bearing capacity of the reverse pressure release plate 191, the reverse pressure release plate 191 releases the gas pressure by cracking, and the gas is released through the exhaust hole 195 on the protective cover 194. In addition, the protective cover 194 usually plays a protective role to prevent foreign objects or external forces from touching the reverse pressure release plate 191 and causing its rated pressure to drop.

[0048] A self-sealing joint 20 can also be provided on the flange tube 13 as needed, and an external device can be connected to realize the internal air vacuuming, inflation and other operations of the present invention, or components such as a gas pressure gauge or an air guide tube can be installed to realize the gas pressure monitoring function.

[0049] like Figure 10As shown, the self-sealing joint 20 includes a support seat 201, an action contact 202, a limiting nut 203 and a spring 204, wherein the lower end of the support seat 201 is provided with a support seat flange 2012 fixedly connected to the flange tube 13, and a vent hole 207 is provided inside the support seat 201, and the lower end of the action contact 202 is supported in the vent hole 207 by the spring 204, and the upper end of the support seat 201 is provided with a limiting nut 203, and the upper end of the action contact 202 extends into the threaded hole in the middle of the limiting nut 203, and the upper side of the support seat 201 is provided with a groove for accommodating the limiting nut 203, and a support seat sealing ring 205 is provided between the limiting nut 203 and the limiting groove surface 2011 at the bottom of the groove, and a contact sealing ring 206 is provided on the action contact 202, and when the action contact 202 is not subjected to external force, the contact sealing ring 206 is against the lower end surface of the limiting nut 203. Under normal conditions, the limiting nut 203 limits and compresses the spring 204, so that the contact sealing ring 206 and the support seat sealing ring 205 are both pressurized to ensure the internal sealing of the present invention. When it is necessary to connect other tools through the self-sealing joint 20, the tool head end is inserted into the threaded hole in the middle of the limiting nut 203 to achieve threaded connection. At the same time, the tool head end pushes the action contact 202 to move downward to compress the spring 204. The contact sealing ring 206 no longer plays a sealing role as the action contact 202 moves downward. The vent hole 207 in the support seat 201 is connected with the air hole in the tool head end. When the tool is removed, the action contact 202 returns to its original position under the action of the spring 204 to achieve re-sealing.

[0050] like Figure 1 As shown, a shielding cover 14 is provided at the lower end of the main insulating layer 1 of the resin-impregnated paper, and the tail terminal 9 is provided in the shielding cover 14 .

[0051] The working principle of the present invention is:

[0052] The main insulating layer 1 of the rubber-impregnated paper of the present invention is made of rubber-impregnated paper oil-free insulating material. The heat resistance of this type of material can reach E grade, which is about 15°C higher than the heat resistance temperature of oil-paper insulation. While ensuring the insulation performance of the bushing, the heat resistance of the bushing is greatly improved. At the same time, the ignition point of the epoxy resin material is above 500°C, which is much higher than the ignition point of transformer oil. Therefore, it is safer and has better flame retardant properties.

[0053] The silicone rubber composite insulating jacket 4 of the present invention is filled with inert gas such as SF6 or N2 instead of transformer oil, which further improves the overall flame retardant performance. In addition, there is no need to fill transformer oil inside the bushing, so the transformer oil will not decompose and produce gas due to internal discharge, thereby preventing fire and combustion.

[0054] The silicone rubber composite insulating jacket 4 of the present invention replaces the traditional porcelain jacket with a silicone rubber composite outer insulating jacket that has higher mechanical strength, better toughness, and does not splash. Since porcelain is a brittle material, once an explosion occurs, it will shatter into sharp-edged fragments that scatter and pose a great threat to surrounding personnel and facilities. The silicone rubber composite outer insulating jacket is mainly made of glass fiber reinforced resin, and high-strength glass fiber runs through it, which has high strength and good toughness. Even in extreme cases of excessive internal pressure, it will not explode. The pressure is only released in the form of cracks at weak points, without explosion or any splash. In addition, the outer side of the silicone rubber composite insulating jacket 4 is staggered with long and short umbrella skirts. By optimizing the electric field design of the sleeve, the maximum radial and axial field strengths of the sleeve are reduced. By reducing the field strength, the sleeve can obtain a higher insulation margin, preventing local discharge or breakdown caused by overvoltage.

[0055] The upper end of the present invention is provided with a head axial sealing and electrical connection component 6 and a head radial sealing component 7, and each sealing component can adopt a design method of combined sealing using a flat ring, an O-ring, a D-ring, etc. as needed, thereby improving the overall sealing performance of the bushing and reducing the risk of discharge failure induced by water entering the bushing due to poor sealing. In the middle part of the present invention, the protrusion 101 of the main insulating layer 1 of the impregnated paper is embedded with the flange tube 13, which, on the one hand, provides support for local sealing to ensure sealing; on the other hand, ensures that the main insulating layer of the impregnated paper is in a stable position on the bushing to avoid displacement.

[0056] The present invention adopts pure copper or oxygen-free high-conductivity copper with better current-carrying performance and thermal conductivity as the current-carrying conductor 2, which fundamentally reduces the temperature rise of the bushing and can effectively solve the problem of thermal breakdown of the main insulation of the bushing. At the same time, the current-carrying conductor 2 adopts an integrated structure, and the head and tail terminals both adopt a welded structure, which improves safety and reliability.

[0057] The present invention features a central flange barrel 13 and mounting flange 3, which are fixed to the transformer housing. These flange barrel 13 and mounting flange 3 are made of non-magnetic stainless steel, with a melting temperature above 1000°C. Even if surrounding equipment or the transformer itself catches fire, the present invention will maintain its fixed position longer than conventional bushings. Furthermore, while the interior of the transformer is an oil environment, the interior of the present invention's bushing is a pressured inert gas environment. A seal is provided between the mounting flange 3 and the primary rubber-impregnated paper insulation layer 1 to prevent the pressured inert gas inside the bushing from entering the transformer's oil and causing transformer failure. Furthermore, the first intermediate sealing element 17, located near the oil environment and near the inert gas environment, is made of different materials to better meet sealing requirements.

[0058] The sleeve of the present invention needs to be filled with an inert gas of a certain pressure. Therefore, a pressure relief device 19 can be provided on the flange tube 13 or the head cover 10 as needed. When the internal gas pressure rises to a specified value, the pressure relief device 19 will be activated to prevent explosion caused by excessive pressure. A self-sealing joint 20 can also be provided on the flange tube 13 as needed. External equipment can be connected to realize the internal air vacuuming, inflation and other operations of the present invention, or gas pressure gauges or gas ducts and other components can be installed to realize the gas pressure monitoring function, while also ensuring that the gas in the tube of the present invention will not leak.

Claims

1. A novel transformer bushing structure with flame retardant and explosion-proof properties, characterized by: The invention comprises a main insulating layer of glue-impregnated paper (1), a current-carrying conductor (2) and a silicone rubber composite insulating jacket (4), wherein the main insulating layer of glue-impregnated paper (1) is sleeved on the outside of the current-carrying conductor (2), the silicone rubber composite insulating jacket (4) is sleeved on the outside of the upper part of the main insulating layer of glue-impregnated paper (1), and a gap filled with inert gas (5) is provided between the upper part of the main insulating layer of glue-impregnated paper (1) and the silicone rubber composite insulating jacket (4), the upper end of the current-carrying conductor (2) is provided with a head terminal (8), the lower end is provided with a tail terminal (9), the upper end of the silicone rubber composite insulating jacket (4) is provided with an upper sleeve flange (12), a head cover ( 10) and a head cover plate (11), wherein the upper sleeve flange (12) is sleeved on the silicone rubber composite insulating jacket (4), the head cover plate (10) is sleeved on the current-carrying conductor (2) and the lower side is fixedly connected to the upper sleeve flange (12), a head radial sealing component (7) is provided between the upper sleeve flange (12) and the head cover plate (10), the head cover plate (11) is sleeved on the current-carrying conductor (2) and is fixedly connected to the upper side of the head cover plate (10), and a head axial sealing and electrical connection component (6) is provided between the head cover plate (11), the head cover plate (10) and the current-carrying conductor (2); The head axial sealing and electrical connection assembly (6) comprises an electrical connection element (602) and a plurality of sealing elements, wherein the first sealing element (601) and the electrical connection element (602) are arranged between the head cover plate (10) and the current-carrying conductor (2), the second sealing element (603) is arranged between the head cover plate (10), the head sealing plate (11) and the current-carrying conductor (2), the third sealing element (604) is arranged between the head sealing plate (11) and the current-carrying conductor (2), and the fourth sealing element (605) is arranged between the head sealing plate (11) and the head cover plate (10); The upper sleeve flange (12) is fixedly connected to the lower side of the head cover (10), and the head radial sealing assembly (7) includes a fifth sealing element (701) and a sixth sealing element (702), wherein the fifth sealing element (701) is arranged between the head cover (10) and the upper sleeve flange (12), and the sixth sealing element (702) is arranged between the head cover (10), the upper sleeve flange (12) and the silicone rubber composite insulating jacket (4).

2. The novel transformer bushing structure with flame retardant and explosion-proof properties according to claim 1 is characterized in that: A shielding cover (14) is provided at the lower end of the main insulating layer (1) of the adhesive-impregnated paper, and the tail terminal (9) is provided in the shielding cover (14).

3. The novel transformer bushing structure with flame retardant and explosion-proof properties according to claim 1 is characterized in that: The middle part of the rubber-impregnated paper main insulation layer (1) is provided with a flange cylinder (13) and a mounting flange (3), the upper end of the flange cylinder (13) is provided with a first flange, and the lower end is provided with a second flange, the outer side of the lower end of the silicone rubber composite insulation jacket (4) is provided with a lower sleeve flange (18), and the lower sleeve flange (18) is fixedly connected to the first flange of the flange cylinder (13), and the second flange is fixedly connected to the mounting flange (3).

4. The novel transformer bushing structure with flame retardant and explosion-proof properties according to claim 3 is characterized in that: A protrusion (101) is provided in the middle of the main insulating layer (1) of the adhesive-impregnated paper, and the flange cylinder (13) is sleeved on the protrusion (101), and the upper end of the protrusion (101) is matched with the first flange stop of the flange cylinder (13), and the lower end is matched with the stop of the mounting flange (3).

5. The novel transformer bushing structure with flame retardant and explosion-proof properties according to claim 3 is characterized in that: A first intermediate sealing element (17) is provided between the mounting flange (3) and the silicone rubber composite insulating jacket (4), a second intermediate sealing element (16) is provided between the mounting flange (3) and the second flange at the lower end of the flange cylinder (13), and a third intermediate sealing element (15) is provided between the first flange at the upper end of the flange cylinder (13) and the lower sleeve flange (18).

6. The novel transformer bushing structure with flame retardant and explosion-proof properties according to claim 5 is characterized in that: The mounting flange (3) is made of non-magnetic stainless steel, the first intermediate sealing element (17) on the transformer side is made of fluororubber, and the first intermediate sealing element (17) on the flange cylinder (13) side is made of EPDM rubber.

7. The novel transformer bushing structure with flame retardant and explosion-proof properties according to claim 3 is characterized in that: The flange cylinder (13) is provided with a pressure relief device (19), and the pressure relief device (19) includes a connecting seat (192), a reverse pressure release plate (191), a fixing plate (193) and a protective cover (194), wherein a gas channel (196) is provided inside the connecting seat (192), the reverse pressure release plate (191) is provided in the gas channel (196), and side plates are provided on both sides of the reverse pressure release plate (191) and are press-fitted and fixed to the connecting seat (192) through the fixing plate (193), a through hole is provided in the middle of the fixing plate (193), and the protective cover (194) is provided on the upper side of the connecting seat (192), and the fixing plate (193) and the reverse pressure release plate (191) are both provided in the protective cover (194), and the protective cover (194) is provided with an exhaust hole (195).

8. The novel transformer bushing structure with flame retardant and explosion-proof properties according to claim 3 is characterized in that: The flange cylinder (13) is provided with a self-sealing joint (20), and the self-sealing joint (20) comprises a support seat (201), an actuating contact (202), a limiting nut (203) and a spring (204), wherein a vent hole (207) is provided inside the support seat (201), the lower end of the actuating contact (202) is supported in the vent hole (207) by the spring (204), the upper end of the support seat (201) is provided with a limiting nut (203), and the upper end of the actuating contact (202) is provided with a limiting nut (203). The end extends into the threaded hole in the middle of the limiting nut (203), the upper side of the support seat (201) is provided with a groove for accommodating the limiting nut (203), and a support seat sealing ring (205) is provided between the limiting nut (203) and the limiting groove surface (2011) at the bottom of the groove, and a contact sealing ring (206) is provided on the action contact (202), and when the action contact (202) is not subjected to external force, the contact sealing ring (206) is against the lower end surface of the limiting nut (203).

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