A transformer with vacuum glass microsphere explosion-proof structure

Abstract

The present application belongs to the technical field of power equipment, and particularly relates to a transformer with a vacuum glass microsphere explosion-proof structure. The vacuum glass microsphere explosion-proof module is directly arranged in the oil tank of the transformer, so that the transformer is not enlarged in size, and has good insulation and service life. When an internal arc fault occurs, if the pressure wave exceeds the pressure threshold of the vacuum glass microsphere, the vacuum glass microsphere is broken, a transient oil and gas containing space is formed to buffer the impact of the shock wave on the tank wall, and substantial pre-pressure relief is realized before the pressure reaches a pressure relief valve or when the pressure relief is insufficient.

Description

Technical Field

[0001] This invention belongs to the field of power equipment technology, and specifically relates to a transformer with a vacuum glass microsphere explosion-proof structure. Background Technology

[0002] When an internal arc fault occurs in an oil-immersed transformer, the arc discharge causes the insulating oil to rapidly decompose, instantly generating a large amount of high-temperature, high-pressure oil gas. Because the transformer tank is a closed structure, the violent gas generation in a short period of time will form a pressure shock wave that propagates in all directions of the tank.

[0003] Although fuel tanks are typically equipped with pressure relief valves or rupture discs on top, which can open to release pressure when the internal pressure exceeds a set threshold, these devices often have a response delay and limited release capacity at the moment of opening. In the event of a strong electric arc fault, they are often unable to promptly suppress the rapid rise in pressure. When the shock wave reaches vulnerable areas such as the tank sidewalls before the pressure relief device acts, it can easily cause structural damage to the tank. Even if the pressure relief device opens, if the release capacity is insufficient, the internal pressure of the tank may continue to rise, eventually leading to tank rupture and serious accidents such as high-temperature fuel gas explosion.

[0004] However, existing protective measures mainly rely on pressure relief valves or rupture discs and other pressure relief devices. Some literature and patents have proposed placing airbag buffer explosion-proof structures inside transformer oil tanks, but the space arrangement is difficult to be compact, regular maintenance is required, and the compatibility of the rubber material of the airbag with transformer oil needs to be considered, so it has not been widely used. Summary of the Invention

[0005] The purpose of this invention is to provide a transformer with a vacuum glass microsphere explosion-proof structure.

[0006] To achieve the above objectives, the present invention provides the following technical solution: The present invention provides a transformer with a vacuum glass microsphere explosion-proof structure, including a transformer tank body and an explosion-proof module arranged on the inner wall surface of the transformer tank body; The explosion-proof module includes vacuum glass microspheres, the critical breakage pressure of which is lower than the maximum pressure that the enclosure can withstand.

[0007] Preferably, the explosion-proof module is a prefabricated plate-shaped structure and / or irregular structure formed by mixing and curing vacuum glass microspheres with adhesive materials.

[0008] Preferably, the irregular structure includes a rounded inner corner, located at the inner corner of the vertically intersecting inner walls of the box.

[0009] Preferably, the explosion-proof module is also provided with an oil groove and / or an oil passage hole for the flow of transformer oil.

[0010] Preferably, the transformer tank body and the explosion-proof module are connected by adhesive bonding or bolts.

[0011] Compared with the prior art, the beneficial effects of the present invention include: This invention directly integrates the vacuum glass microsphere explosion-proof module inside the oil tank, without increasing the transformer's size, and provides excellent insulation and service life. When an internal arc fault occurs, if the pressure wave exceeds the pressure resistance threshold of the vacuum glass microsphere, the microsphere will rupture, creating a momentary oil and gas containment space to buffer the impact of the shock wave on the tank wall. This achieves substantial pre-pressure relief before the pressure reaches devices such as pressure relief valves or when pressure relief is insufficient.

[0012] Specifically: When an internal arc fault occurs in an oil-immersed transformer, the arc duration can typically reach tens of milliseconds or even longer, during which a large amount of energy is rapidly released, causing the insulating oil to decompose and generate high-temperature, high-pressure gas, forming a rapidly rising internal pressure shock wave. Normally, pressure relief devices such as pressure relief valves or rupture discs installed on the top of the tank rely on the pressure wave propagating along the oil medium to the sensing point, with a response time of approximately several milliseconds. Before the pressure relief channel is fully formed, the pressure wave has already reached structural parts closer to the fault point on the side wall of the tank, causing a rapid increase in local pressure. With the installation of a vacuum glass microsphere explosion-proof module, when the pressure in this area reaches the preset activation threshold of the vacuum glass microsphere near the inner wall of the tank, the vacuum glass microsphere will rupture, thus creating an instantaneous space for oil and gas containment and release inside the tank. This process occurs within a few milliseconds of the pressure relief mechanism not yet being fully activated. Although the total amount of gas generated during the fault is relatively limited by the energy level and duration of the electric arc, the equivalent volume expansion provided by the instantaneous rupture of the vacuum glass microspheres actually constitutes a rapid release path for the early gas generation. Its effect is equivalent to forming a high-flow instantaneous discharge at this local location, thereby effectively mitigating the pressure peak and playing an auxiliary explosion-proof role in suppressing damage to the tank structure.

[0013] For slow pressure increases inside the tank due to slow gas production or other reasons, the vacuum glass microspheres will not rupture because their critical breakage pressure is higher than that of the pressure relief valve or explosion-proof membrane. The pressure is then released normally by the pressure relief device. For low- to medium-energy arcing faults, with sufficient filling module placement, the tank shell will not experience pressure waves. For higher-energy arcing faults, the rate of pressure rise in the tank shell can be significantly reduced before the pressure relief device takes effect. This transient pressure buffering mechanism based on the principle of vacuum glass microsphere rupture has significant engineering application value in the active explosion-proof design of transformers. Attached Figure Description

[0014] Figure 1This is a schematic diagram of the explosion-proof module in this invention; Figure 2 This is a schematic diagram of the transformer with a vacuum glass microsphere explosion-proof structure provided by the present invention. Detailed Implementation

[0015] The present invention provides a transformer with a vacuum glass microsphere explosion-proof structure, including a transformer tank body and an explosion-proof module arranged on the inner wall surface of the transformer tank body; The explosion-proof module includes vacuum glass microspheres, the critical breakage pressure of which is lower than the maximum pressure that the enclosure can withstand.

[0016] In this invention, the critical breakage pressure of the vacuum glass microspheres is lower than the maximum pressure that the chamber can withstand. In a specific embodiment, the critical breakage pressure of the vacuum glass microspheres is preferably 0.2~0.6MPa, which can be adjusted according to actual explosion-proof requirements and is not specifically limited.

[0017] In this invention, the vacuum glass microspheres are preferably made of borosilicate glass, and more preferably low-alkali borosilicate glass; borosilicate glass itself has high dielectric strength, high volume resistivity, and strong chemical inertness. In this invention, the dielectric breakdown field strength of the vacuum glass microspheres is preferably 18–30 kV / mm. In this invention, the dielectric breakdown field strength of the vacuum glass microspheres is higher than the 10–16 kV / mm range of mineral transformer oil, exhibiting no normal discharge and no heat accumulation, thus meeting the requirements for 30 years of long-term oil-immersion operation.

[0018] In this invention, the particle size of the vacuum glass microspheres is preferably 60μm~100μm, and the cavity volume of the vacuum glass microspheres preferably accounts for more than 90% of the total volume of the microspheres. In this invention, the volume filling rate of the vacuum glass microspheres in the explosion-proof module is preferably 60%~70%. In this invention, the interior of the vacuum glass microspheres is close to a vacuum state, allowing the presence of trace amounts of inert gas. In this invention, the vacuum glass microspheres are micron-level sealed cavities, which are different from millimeter-level bubbles and open air gaps, and their discharge laws are completely different: micron-level air gaps do not have conventional air breakdown channels, the Paschen curve breakdown threshold is significantly raised, and they have extremely strong resistance to normal discharge. Arranging them inside a conventional transformer casing will not cause discharge.

[0019] In this invention, the explosion-proof module is preferably a prefabricated plate-like structure and / or an irregularly shaped structure formed by mixing and curing vacuum glass microspheres with an adhesive material; the adhesive material preferably includes electrical insulation grade epoxy resin. In this invention, the adhesive material has good compatibility with transformer oil and exhibits minimal attenuation of volume resistivity and dielectric strength after long-term oil immersion. In this invention, the irregularly shaped structure preferably includes rounded inner corners located at the inner corners of the perpendicularly intersecting inner walls of the enclosure.

[0020] This invention does not impose any particular limitation on the preparation method of the explosion-proof module; it can be prepared using methods well-known to those skilled in the art and molds of the required shape. In the specific preparation process, it is necessary to prevent the formation of millimeter- or micrometer-sized process bubbles inside the explosion-proof module, thereby avoiding discharge caused by these bubbles under the influence of the electric field inside the transformer.

[0021] In this invention, the explosion-proof module is preferably provided with an oil channel and / or an oil passage hole for the flow of transformer oil; during normal operation, it does not obstruct the internal oil circulation and heat dissipation of the transformer; the explosion-proof module is dense and without pores or sharp protrusions, so it will not cause local electric field distortion or reduce the original insulation level of the transformer. This invention does not impose any special limitations on the size of the oil channel and / or oil passage hole; sizes well known to those skilled in the art can be used.

[0022] In this invention, the transformer tank body and the explosion-proof module are preferably connected by adhesive bonding or bolting; when adhesive bonding is used, the bonding surface is ensured to be flat and without gaps or suspended air gaps.

[0023] This invention does not impose any special limitations on the size of the explosion-proof module, and it can be adjusted according to different transformer specifications and specific explosion-proof requirements; in a specific embodiment, the thickness of the prefabricated plate structure can be 8mm. In this invention, by controlling the thickness of the prefabricated plate structure, structural strength, explosion-proof gas capacity, and oil flow compatibility are all taken into account.

[0024] In this invention, the explosion-proof module preferably includes a thermally conductive material; the thermally conductive material preferably includes at least one of boron nitride and aluminum oxide; by adding a thermally conductive material, the thermal conductivity of the explosion-proof module can be further improved.

[0025] In this invention, the explosion-proof module is arranged on the inner wall of the oil tank, avoiding the installation area of ​​the top pressure relief valve or rupture disc, making reasonable use of the inherent gap between the oil tank shell and the internal body, and not encroaching on the core working space of the iron core and winding core; the preferred arrangement position is the weak area of ​​the oil tank that is most first impacted by the arc pressure shock wave and most prone to bulging and rupture, so as to respond to the pressure shock at the first time and realize pre-pressure relief and energy absorption.

[0026] In this invention, the explosion-proof module does not reduce the insulation level between the original components inside the transformer, and the overall electrical safety boundary of the system remains unchanged; it is also maintenance-free for a long time, easy to form and arrange, and has low requirements for the internal layout space of the transformer.

[0027] The structural schematic diagram of the transformer with a vacuum glass microsphere explosion-proof structure provided by this invention is shown below. Figure 2 As shown in the diagram, the explosion-proof module's structural schematic is as follows: Figure 1 As shown.

[0028] The technical solutions of this invention will be clearly and completely described below with reference to the embodiments thereof. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0029] Example 1 Taking a conventional corrugated oil tank of a certain type of 10kV fully sealed oil-immersed distribution transformer with a capacity of 400kVA as an example; The vacuum glass microspheres are made of low-alkali borosilicate glass; the microsphere particle size is controlled within the range of 60~100μm, the critical breakage pressure is 0.3~0.45MPa, the vacuum cavity volume ratio in a single microsphere is greater than 96%, the dielectric breakdown field strength of the microsphere is 18~30kV / mm, there is no normal discharge and no heat accumulation, and it meets the requirements for 30 years of long-term oil immersion operation. Vacuum glass microspheres were cured and molded using electrical insulating grade epoxy resin to obtain a dense, non-porous prefabricated plate-shaped explosion-proof module with a single plate thickness of 8 mm and a microsphere volume fill rate of 65%. The explosion-proof module is placed on the inner wall of the fuel tank, in the weakest area of ​​the tank where the arc pressure shock wave will first impact and where bulging and rupture are most likely to occur. This allows for immediate response to pressure shocks and pre-pressure relief to absorb energy. The total internal area of ​​the fuel tank is 8.2 m². 2 The area that can be arranged is calculated to be 80%, and the total volume of the arrangement module is 52.5L. The filler is bonded to the inner wall of the oil tank using electrical insulation grade epoxy adhesive. The bonding surface is flat and without gaps or suspended air gaps. When a high-energy-level arcing fault occurs in this type of transformer, the arc duration is 30ms and the fault arc energy is 550kJ. During the entire arcing process, the volume of gas produced by the cracked insulating oil is 63L under standard conditions, and the peak pressure exceeds 0.45MPa. The total volume of the module is 52L. Combined with the vacuum glass microsphere volume filling rate of 62% and the vacuum inner cavity volume ratio of 96%, a 31L capacity space can be formed. This effectively fills the 5~12ms response delay window of the pressure relief valve installed in this type of transformer, achieving millisecond-level pre-pressure relief and shock wave peak clipping and energy absorption. The instantaneous impact pressure is controlled below the yield strength of the oil tank, avoiding oil tank rupture and completely eliminating oil and gas explosion accidents.

[0030] Although the above embodiments have provided a detailed description of the present invention, they are only some embodiments of the present invention, and not all embodiments. Other embodiments can be obtained based on these embodiments without creative effort, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A transformer with a vacuum glass microsphere explosion-proof structure, characterized in that, It includes a transformer tank body and an explosion-proof module disposed on the inner wall surface of the transformer tank body; The explosion-proof module includes vacuum glass microspheres, the critical breakage pressure of which is lower than the maximum pressure that the enclosure can withstand.

2. The transformer according to claim 1, characterized in that, The explosion-proof module is a prefabricated plate-shaped structure and / or irregular structure formed by mixing and curing vacuum glass microspheres with adhesive materials.

3. The transformer according to claim 2, characterized in that, The irregular structure includes a rounded inner corner, located at the inner corner of the inner walls that intersect perpendicularly with the box body.

4. The transformer according to claim 2 or 3, characterized in that, The explosion-proof module is also provided with an oil passage groove and / or an oil passage hole for the flow of transformer oil.

5. The transformer according to claim 1, characterized in that, The transformer tank body and the explosion-proof module are connected by adhesive bonding or bolts.

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