Electric explosion driven oil immersed transformer rapid pressure relief diaphragm and instantaneous cutting method

Abstract

The invention discloses an electric explosion driven oil immersed transformer rapid pressure relief diaphragm and an instant cutting method. The device is characterized in that a pressure relief piece is pressed on a base through a pressing ring, the base is installed on an oil tank of an oil immersed transformer, and a sealing rubber ring is arranged between the base and the oil tank of the oil immersed transformer and between the face, facing the base, of the pressure relief piece and the oil tank of the oil immersed transformer; the electric explosion load comprises an inner conductor, an outer conductor, a flyer and a soft insulating material; the wire groove is formed in the base, and a coaxial wire is placed in the wire groove; the inner conductor, the outer conductor and the flyer are integrally packaged through a soft insulating material, and the inner conductor is packaged in the outer conductor through the soft insulating material; the electric explosion load is connected with a power supply through a coaxial wire; the electric explosion load and the pressure relief piece are isolated through a limiting piece, a groove is formed in the face, facing the pressure relief piece, of the base, and the electric explosion load is placed on the groove of the base; one side of the flyer is provided with a wedge-shaped blade structure facing the pressure relief sheet, the other side of the flyer faces one side of the outer conductor, and the other side of the outer conductor faces the slot of the base.

Description

Technical Field

[0001] The present invention belongs to the technical field of safety protection of electric power equipment, and in particular relates to a rapid pressure relief diaphragm of an oil-immersed transformer driven by electric explosion and an instantaneous cutting method. Background Art

[0002] Transformers are essential, critical equipment in power systems, widely used in power generation, transmission, transformation, and distribution. Their operational safety and stability directly impact the reliability and continuity of power grids. Over long-term operation, transformers may develop internal short-circuit faults due to insulation aging, structural defects, or electrical shocks. Short-circuit arc faults, in particular, are the most destructive and severe of all fault types. When an arc fault occurs, the current density in a localized area rapidly increases, forming a high-temperature, high-pressure plasma channel that releases a large amount of electrical energy. This energy, in the form of thermal energy, rapidly heats the transformer oil, causing vaporization and cracking. Furthermore, it generates mechanical energy, generating shock waves or pressure waves within the oil. These waves can impact the transformer tank structure, causing it to swell, permanently deform, or even rupture and explode. These serious threats to equipment safety and grid stability pose a significant risk of engineering disasters.

[0003] Current pressure relief technologies used in oil-immersed transformers include pressure relief valves, explosion-proof membrane pressure relief devices, explosion-proof membrane pressure relief valves, and rapid pressure relief systems. The explosion-proof membrane is a key component for rapidly releasing overpressure during arc faults. When the pressure and rate of rise reach the rupture threshold, the membrane ruptures, connecting the inside and outside of the tank through a sufficiently large pressure relief area. This prevents deformation and rupture of the tank itself and reduces the risk of subsequent fires. Currently, the bursting membrane typically operates for more than 5ms, making it ineffective in interrupting the explosion chain reaction. Summary of the Invention

[0004] This invention aims to overcome the slow response problem of oil-immersed transformer pressure relief devices. It proposes an electric explosion-driven rapid pressure relief diaphragm for oil-immersed transformers and a method for its instantaneous cutting. By using the electric explosion to drive the cutting of the flying blades, a millisecond-level pressure relief response is achieved in the event of an internal transformer fault, preventing the oil tank from bursting.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions: In a first aspect, the present invention provides an oil-immersed transformer rapid pressure relief diaphragm driven by electric explosion, comprising a pressure relief plate, a base, a pressure ring, an electric explosion load, a limit plate, a sealing rubber ring, and a wire trough; The pressure relief plate is pressed onto the base through a pressure ring. The middle hole of the base, the pressure relief plate, and the middle hole of the pressure ring are arranged parallel to each other. The base is installed on the oil tank of the oil-immersed transformer. The sealing rubber ring is arranged between the base, the side of the pressure relief plate facing the base, and the oil tank of the oil-immersed transformer. The electric explosion load includes an inner conductor, an outer conductor, flying pieces and soft insulating materials; a wire trough is opened on the base, and a coaxial wire is placed in the wire trough; The electric explosion load is a coaxial return structure. The inner conductor, outer conductor and flying piece are integrated and packaged by soft insulating material. The inner conductor is packaged inside the outer conductor by soft insulating material. The electric explosion load is connected to the power supply through a coaxial wire. The electric explosion load is isolated from the pressure relief plate by a limit plate. A slot is provided on the side of the base facing the pressure relief plate, and the electric explosion load is placed on the slot of the base. One side of the flying piece is provided with a wedge-shaped blade structure facing the pressure relief piece, the other side of the flying piece faces one side of the outer conductor, and the other side of the outer conductor faces the slot of the base.

[0006] Furthermore, the bottom of the slot of the base is a parabolic surface, and the inner conductor 8 is located at the parabola focus of the parabolic surface.

[0007] Furthermore, the inner conductor adopts a conductor with a low melting point and high conductivity, including metal foil.

[0008] Furthermore, the electric explosion load is connected to one end of the capacitor through the core wire of the coaxial wire; the high voltage end of the capacitor is grounded, the other end of the capacitor is connected to the power supply, and the sheath wire of the coaxial wire is grounded; When capacitor discharge is used to drive the electric explosion, the length and diameter of the inner conductor are set using the following formula:

[0009] in, d opt is the inner conductor diameter, l opt is the inner conductor length, L is the circuit inductance, C is the circuit capacitance, U 0 is the capacitor charging voltage, W 0 is the initial capacitor energy storage, ρ 0 is the metal material density of the inner conductor, σ 0 is the conductivity of the inner conductor metal material, λ is the melting specific energy, r is the specific energy of vaporization.

[0010] Furthermore, a petal-shaped structure to be cut is provided on the pressure relief piece, and the pressure ring presses the pressure relief piece onto the base through the petal-shaped structure to be cut. The electric explosion load is placed between the petal-shaped structure to be cut and the slot, and the single petal width of the petal-shaped structure to be cut is smaller than the length of the inner conductor.

[0011] Furthermore, the number, width and thickness of the petal-shaped structure to be cut are determined by static simulation based on the relationship between the maximum normal oil pressure of the oil tank of the oil-immersed transformer and the yield strength of the material used; The relationship between the maximum normal oil pressure of the oil tank and the yield strength of the material used is: the maximum equivalent stress of the petal-shaped structure to be cut under the maximum normal oil pressure of the oil-immersed transformer tank is less than half of the yield strength of the material used.

[0012] Furthermore, when the thickness of the petal-shaped structure to be cut of the pressure relief piece reaches 1 mm, the speed of the flying pieces after the inner conductor is detonated exceeds 150 m / s.

[0013] Furthermore, the mass of the flyer is set by the following formula:

[0014] in, is the quality of the flying piece, is the flying piece speed during electric explosion, W 0 is the initial capacitor energy storage.

[0015] Furthermore, the flyer is made of high-density and high-hardness material.

[0016] On the second side, the present invention provides a method for instantaneously cutting a fast pressure relief diaphragm of an oil-immersed transformer driven by an electric explosion, using a fast pressure relief diaphragm of an oil-immersed transformer driven by an electric explosion, comprising the following steps: The external input short-circuit fault signal triggers the pulse power supply to discharge the inner conductor encapsulated in the soft insulating material, driving the electric explosion; The high-pressure plasma, metal vapor and shock wave generated by the electric explosion act on the flying piece. The wedge-shaped blade structure of the flying piece hits and cuts off the pressure relief piece. The time from the start of the electric explosion to the cutting of the pressure relief piece is less than 0.2ms, completing the instantaneous cutting of the oil-immersed transformer's rapid pressure relief diaphragm.

[0017] Compared with the prior art, the present invention has the following beneficial technical effects: This invention proposes a rapid pressure relief diaphragm for oil-immersed transformers driven by an electrical explosion. The pressure relief diaphragm is press-fitted to the base via a pressure ring, providing a tight fit with the oil tank. A sealing rubber ring further enhances the seal, effectively preventing transformer oil leakage and ensuring safe and stable operation. The electrical explosion load utilizes a coaxial return structure, with the inner and outer conductors and flyer plates integrally encapsulated by soft insulating material. The design is sophisticated and compact, and coaxial wires are placed in a cable tray for easy connection to the power supply, ensuring stable current transmission. The electrical explosion load is separated from the pressure relief diaphragm by a stopper, and a slot in the base provides a stable placement for the electrical explosion load, ensuring a stable and reliable overall structure. A wedge-shaped blade structure on one side of the flyer plate faces the pressure relief plate. When an electrical explosion occurs, the flyer plate quickly impacts the pressure relief plate, achieving rapid pressure relief and promptly releasing excessive pressure generated by a transformer fault. This prevents the oil tank from rupturing due to excessive pressure, significantly reducing the risk of explosion and accident losses, effectively ensuring the safety of the transformer and its surrounding environment, and improving the reliability and stability of power system operation. The invention reduces the time required to disconnect the pressure relief plate by an order of magnitude. Combined with the multi-parameter fault monitoring technology currently under development within the transformer, the overall fault pressure relief response time can be reduced to the sub-millisecond level, effectively preventing oil tank rupture and explosion accidents caused by short-circuit faults.

[0018] This invention proposes a method for instantaneously disconnecting the pressure-relief diaphragm of an oil-immersed transformer driven by an electric explosion. This method uses an external short-circuit fault signal to trigger a pulse power supply discharge, rapidly driving the electric explosion with exceptionally sensitive response. The high-pressure plasma, metal vapor, and shock wave generated by the electric explosion act synergistically on the flyer blades, effectively impacting and severing the pressure-relief diaphragm using the flyer blade's wedge-shaped blade structure. The time from the start of the electric explosion to the severance of the pressure-relief diaphragm is less than 0.2 milliseconds, achieving rapid instantaneous disconnection. This method can rapidly relieve excessive pressure in the event of a sudden fault in an oil-immersed transformer, preventing an oil tank rupture or explosion. This significantly improves transformer operational safety and reduces accident losses. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The drawings described herein are for illustrative purposes only and are not intended to limit the scope of the present invention in any way. In addition, the shapes and proportional dimensions of the components in the drawings are only schematic and are used to help understand the present invention, and are not intended to specifically limit the shapes and proportional dimensions of the components of the present invention. In the drawings: Figure 1 This is a structural diagram of a rapid pressure relief diaphragm for an oil-immersed transformer driven by electric explosion.

[0020] Figure 2 A partial cross-sectional view of a rapid pressure relief diaphragm for an oil-immersed transformer driven by electric explosion.

[0021] Figure 3 This is a cross-sectional diagram of the electric explosion load of an oil-immersed transformer rapid pressure relief diaphragm driven by electric explosion.

[0022] Figure 4 It is the 0th ms of the cutting process simulated by the dynamic simulation in the embodiment.

[0023] Figure 5 This is the 0.01ms of the dynamic simulation cutting process in the embodiment.

[0024] Figure 6 This is the 0.02ms of the dynamic simulation cutting process in the embodiment.

[0025] Among them, 1-pressure relief plate, 2-base, 3-pressure ring, 4-electric explosion load, 5-limiting plate, 6-sealing rubber ring, 7-wire slot, 8-inner conductor, 9-outer conductor, 11-flying plate, 10-soft insulating material. DETAILED DESCRIPTION

[0026] In order to enable those skilled in the art to better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of the present invention.

[0027] It should be noted that when an element is referred to as being "disposed on" another element, it may be directly on the other element or there may be an element centered thereon. When an element is referred to as being "connected to" another element, it may be directly connected to the other element or there may be an element centered thereon. The terms "vertical," "horizontal," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only embodiments.

[0028] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one skilled in the art to which this invention pertains. The terms used in this specification of the present invention are for the purpose of describing specific embodiments only and are not intended to limit the present invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0029] It should be noted that the terms "first", "second", etc. in the description and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that the numbers used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0030] Example 1 A rapid pressure relief diaphragm for an oil-immersed transformer driven by electric explosion, comprising a pressure relief plate 1, a base 2, a pressure ring 3, an electric explosion load 4, a limit plate 5, a sealing rubber ring 6, and a wire groove 7; the pressure relief plate 1 is pressed onto the base 2 through the pressure ring 3, the middle hole of the base 2, the pressure relief plate 1, and the middle hole of the pressure ring are arranged parallel to each other, the base 2 is installed on the oil tank of the oil-immersed transformer, the sealing rubber ring 6 is arranged between the base 2, the side of the pressure relief plate 1 facing the base 2, and the oil tank of the oil-immersed transformer; the electric explosion load 4 comprises an inner conductor 8, an outer conductor 9, a flying plate 11, and a soft insulating material 10; the wire groove 7 is opened on the base 2, and a wire groove 7 is placed Coaxial wire; the electric explosion load 4 is a coaxial return structure, the inner conductor 8, the outer conductor 9, and the flying piece 11 are integrated into a package through a soft insulating material 10, and the inner conductor 8 is encapsulated inside the outer conductor 9 through a soft insulating material 10; the electric explosion load 4 is connected to the power supply through a coaxial wire; the electric explosion load 4 and the pressure relief piece 1 are isolated by a limit piece 5, and a slot is provided on the side of the base 2 facing the pressure relief piece 1, and the electric explosion load 4 is placed on the slot of the base 2; one side of the flying piece 11 has a wedge-shaped blade structure facing the pressure relief piece 1, the other side of the flying piece 11 faces one side of the outer conductor 9, and the other side of the outer conductor 9 faces the slot of the base 2.

[0031] This embodiment responds quickly to pressure relief, and the electric explosion load adopts a coaxial return structure and an integrated packaging design. After connecting to the power supply, it can be quickly triggered when the internal pressure of the transformer is abnormal. The wedge-shaped blade structure on the flying piece can quickly pierce the pressure relief piece, release the pressure in time, and prevent the transformer from exploding. The sealing performance is good, and the sealing rubber ring is arranged between the base, the pressure relief piece and the oil tank to effectively prevent the transformer oil from leaking and ensure the normal operation of the equipment. The structure is stable and reliable, and the base is provided with a slot to place the electric explosion load, and the electric explosion load and the pressure relief piece are isolated by a limit piece. The various components are firmly installed and accurately positioned to ensure that the structure does not loosen or shift during normal operation and pressure relief. In addition, the wire trough design facilitates the arrangement of coaxial wires, making the overall structure compact and reasonable, saving space, and facilitating installation and maintenance, thereby improving the safety and stability of transformer operation.

[0032] The slotted bottom of the base 2 is a parabolic surface, with the inner conductor 8 located at the parabolic focus of the parabolic surface. The inner conductor 8 is made of a low-melting-point, high-conductivity conductor, such as metal foil. The electric explosion load 4 is connected to one end of a capacitor via the core wire of a coaxial conductor. The high-voltage terminal of the capacitor is grounded, while the other end of the capacitor is connected to a power source, and the outer wire of the coaxial conductor is grounded. When the electric explosion is driven by capacitor discharge, the length and diameter of the inner conductor 8 are set using the following formula:

[0033] in, d opt is the inner conductor diameter, l opt is the inner conductor length, L is the circuit inductance, C is the circuit capacitance, U 0 is the capacitor charging voltage, W 0 is the initial capacitor energy storage, ρ 0 is the metal material density of the inner conductor, σ 0 is the conductivity of the inner conductor metal material, λ is the melting specific energy, r is the specific energy of vaporization.

[0034] The pressure relief piece 1 is provided with a petal-shaped structure to be cut, and the pressure ring 3 presses the pressure relief piece 1 onto the base 2 through the petal-shaped structure to be cut. The electric explosion load 4 is placed between the petal-shaped structure to be cut and the slot, and the width of a single petal of the petal-shaped structure to be cut is less than the length of the inner conductor 8. The number, width and thickness of the petal-shaped structure to be cut are determined by static simulation based on the relationship between the maximum normal oil pressure of the oil-immersed transformer tank and the yield strength of the material used; the relationship between the maximum normal oil pressure of the oil tank and the yield strength of the material used is: the maximum equivalent stress of the petal-shaped structure to be cut under the maximum normal oil pressure of the oil-immersed transformer tank is less than half of the yield strength of the material used. When the thickness of the petal-shaped structure to be cut of the pressure relief piece 1 reaches 1mm, the speed of the flying piece 11 exceeds 150m / s after the inner conductor 8 is detonated. The mass of the flying piece 11 is set by the following formula:

[0035] in, is the quality of the flying piece, is the flying piece speed during electric explosion, W 0 is the initial capacitor energy storage.

[0036] The flying piece 11 is made of high-density and high-hardness material.

[0037] In this embodiment, the slotted bottom of the base is a parabolic surface, with the inner conductor at the focal point, concentrating the electric explosion energy on the flying discs. The pressure relief discs are designed with a petal-shaped structure to be cut, and the electric explosion load is positioned appropriately. After the inner conductor is detonated, the flying discs, driven by precise energy, rush toward the pressure relief discs at speeds exceeding 150 m / s, rapidly cutting through the petal-shaped structure and achieving rapid pressure relief, preventing damage to the transformer due to excessive pressure. Each component is precisely installed and positioned, with pressure rings, limiters, and other components ensuring structural stability. The inner conductor is made of low-melting-point, highly conductive metal foil, which facilitates the occurrence of the electric explosion; the flying discs are made of high-density, high-hardness material to ensure effective cutting. Furthermore, static simulations were performed to determine the petal-shaped structural parameters based on the maximum normal oil pressure of the tank and the material's yield strength, ensuring structural safety under normal oil pressure. Sealing rubber rings are positioned at key locations to effectively prevent transformer oil leaks. The electric explosion load adopts a coaxial return structure with a reasonable connection method. It is driven by capacitor discharge. The relevant parameters are accurately set through formulas to ensure that the electric explosion process is stable and reliable, improve the safety of transformer operation, reduce accident risks, and ensure stable operation of the power system.

[0038] Example 2 A method for instantaneously cutting a rapid pressure relief diaphragm of an oil-immersed transformer driven by an electric explosion, using the rapid pressure relief diaphragm of an oil-immersed transformer driven by an electric explosion in Example 1, comprising the following steps: An external input short-circuit fault signal triggers a pulse power supply to discharge the inner conductor 8 encapsulated in the soft insulating material 10, driving an electric explosion. The high-voltage plasma, metal vapor, and shock wave generated by the electric explosion act on the flying piece 11. The wedge-shaped blade structure of the flying piece 11 strikes and cuts off the pressure relief piece 1. The time from the start of the electric explosion to the cutting of the pressure relief piece 1 is less than 0.2ms, completing the instantaneous cutting of the oil-immersed transformer's rapid pressure relief diaphragm.

[0039] This embodiment can discharge the inner conductor to drive an electric explosion in a very short time. The time from the start of the electric explosion to the cutting of the pressure relief plate is less than 0.2ms. It can quickly respond to the sudden increase in pressure caused by the fault inside the transformer and open the pressure relief channel in time, effectively preventing the oil tank from rupturing and exploding due to excessive pressure, greatly reducing the degree of accident damage, and ensuring the safety of equipment and the surrounding environment. The high-pressure plasma, metal vapor and shock wave generated by the electric explosion act synergistically on the flying piece, and the wedge-shaped blade structure of the flying piece is used to impact and cut off the pressure relief plate. This multi-energy composite action mode ensures the reliability and thoroughness of the cut, and can quickly and stably complete the pressure relief action. It has good compatibility with the overall system of the oil-immersed transformer, and does not require large-scale transformation of the transformer. It is easy to apply and promote in actual engineering, and provides an efficient and feasible means of ensuring the safe operation of the oil-immersed transformer.

[0040] Example 3 See also Figure 1 and Figure 2, a structural diagram of an oil-immersed transformer rapid pressure relief diaphragm driven by electric explosion, including a pressure relief plate 1, a base 2, a pressure ring 3, an electric explosion load 4, a limit plate 5, a sealing rubber ring 6, and a wire groove 7; See also Figure 3 The electric explosion load 4 is a coaxial return structure, which is encapsulated by a soft insulating material 10 (not limited to silicone rubber). The inner conductor 8, the outer conductor 9, the flying piece 11 and the low-inductance coaxial wire are integrated into a package, which simplifies the circuit connection and improves the load current rise rate; The wire trough 7 is used to place the coaxial wire; The base 2 is mounted on the oil tank of the transformer. Under normal circumstances, the pressure inside the oil tank is not necessarily equal to the external pressure, and is generally higher than the atmospheric pressure. The sealing rubber ring 6 is used to prevent oil leakage. The electric explosion load 4 is isolated from the pressure relief plate 1 by a limit plate 5 to ensure the acceleration distance of the flying plate 11 before hitting the pressure relief plate 1; the limit plate 5 is made of a relatively thin material. Under normal circumstances, the limit plate 5 is used to clamp the electric explosion load 4. During an electric explosion, it can be easily pushed to hit the pressure relief plate 1 and be cut off.

[0041] The bottom of the slot on the base 2 for placing the electric explosion load 4 is a parabolic surface, and the inner conductor 8 is located at the focus of the parabola; The inner conductor 8 is made of a low-melting-point, high-conductivity conductor (not limited to copper wire, aluminum wire, or aluminum wire with a CuO coating). Its length and diameter match the power supply parameters. When capacitor discharge is used to drive the electric explosion, the calculation method is as follows:

[0042] in d opt 、 l opt are the wire diameter and length, L 、 C are the circuit inductance and capacitance, U 0 is the capacitor charging voltage, W 0 is the initial capacitor energy storage, ρ 0. σ 0 is the density and conductivity of the metal material, λ and r are the melting and vaporization specific energies (unit: J / kg), respectively. The above physical quantities are all in SI units; The pressure relief disc 1 has a petal-shaped structure to be cut. The width of a single disc is less than the length of the metal wire of the inner conductor 8. The number of discs, width, and thickness of the pressure relief disc are determined through static simulation based on the maximum normal oil pressure of the fuel tank and the yield strength of the material used (not limited to 316 stainless steel). This ensures that the maximum equivalent stress of the petal structure of the pressure relief disc 1 under the maximum normal oil pressure is less than half of the yield strength. The pressure ring 3 presses the petal-shaped structure to be cut of the pressure relief disc 1 onto the base 2, and the electric explosion load 4 is below the petal-shaped structure to be cut. The flyer 11 is made of high-density and high-hardness material (preferably tungsten-based alloy). The length of the flyer 11 is equivalent to the length of the metal wire of the inner conductor 8. The front end has a wedge-shaped blade structure. When the thickness of the pressure relief plate 1 to be cut reaches 1mm, the speed of the flyer 11 after detonation should exceed 150m / s, preferably 200m / s. The quality of the flyer 11 is comprehensively selected with the energy storage of the capacitor. The preliminary design can be based on ,After completing the preliminary design, the display dynamics simulation is ,used to verify the cutting effect.

[0043] Example 2 An electric explosion-driven flying disc is used to sever the pressure relief diaphragm of a transformer. This example uses a 500kV transformer as an example. The pressure relief port diameter is 300mm. The pressure relief disc is made of 316 stainless steel, with a 2mm thick oil pressure-resistant portion and a 40mm wide, 1mm thick, petal-shaped structure. Six discs are evenly spaced. Static simulations were performed at a maximum net oil pressure of ±50kPa in the oil tank. The maximum displacement of the central portion of the pressure relief disc was 1.5mm, and the stress of the petal-shaped structure was less than 30MPa, far below the yield strength of 316 stainless steel (>170MPa).

[0044] The capacitance of the single-petal cutting capacitor is selected as 6μF, the charging voltage is 13kV, the total energy storage capacitance of the six-petal is 36μF, the total energy storage is 3kJ, and the energy density of the pulse capacitor is selected as 2MJ / m 3 The total volume of the energy storage capacitor is about 1.5 L. The capacitor is continuously powered by a high-voltage package, the high-voltage end is grounded through a thyristor, and the other end is connected to the coaxial wire core and connected to the electric explosion load, and the coaxial wire skin is grounded.

[0045] The electric explosion load is made of copper wire with a diameter of 0.3mm and a length of 40mm; the flying piece is made of tungsten alloy with a length of 50mm, a width of 4mm, a height of 4mm, and a density of 17g / cm 3 The cross section is triangular and the total mass is 6.8g; the soft insulating packaging material is silicone rubber; the limit piece is made of 1mm thick polytetrafluoroethylene, and the flying piece blade is 3mm away from the pressure relief piece.

[0046] The total inductance of the wire from the energy storage capacitor to the electric explosion load is less than 2μH (corresponding to a 4m wave impedance 50ohm coaxial cable). The shock wave overpressure generated by the electric explosion during discharge is approximately assumed to decay according to the power of 0.5 of the distance. The measured shock wave pressure peak at 5cm away from the metal wire is 50MPa. Therefore, the bottom pressure of the flying piece during the whole acceleration process is greater than 150MPa, and the acceleration is greater than 4.4×10 6 m / s 2 ; The acceleration distance of the flying piece is 4mm, so the final velocity at the time of impact is >187m / s, and the acceleration time is 0.043ms.

[0047] See also Figure 4 、 Figure 5 、 Figure 6 ,The cutting process is simulated by display dynamics simulation, and it can be seen that the time from impact to cutting completion is less than 0.02ms.

[0048] Taking into account the thyristor drive circuit and the conduction action delay of 0.002ms, the total time required for the device to cut off the pressure relief plate from receiving the external trigger signal is about 0.065ms.

[0049] Example 4 A method for instantaneously cutting a transformer pressure relief diaphragm by driving a flying piece with an electric explosion, using the flying piece driven by an electric explosion to cut the transformer pressure relief diaphragm in Example 3, comprising the following steps: The external input short-circuit fault signal triggers the pulse power supply to discharge the metal wire or metal foil encapsulated in the insulating material. The pulse current period is at the level of 10μs and the current amplitude is at the level of 10kA, driving the electric explosion. The high-pressure plasma, metal vapor and shock wave generated by the electric explosion act on the cutting flying pieces, causing them to reach a high speed of hundreds of meters per second within an acceleration distance of less than 5mm; The flying pieces hit and cut off the pressure relief plate. The total duration of the whole process (from electric explosion to cutting off the pressure relief plate) is less than 0.2ms.

[0050] Many embodiments and applications beyond the examples provided will be apparent to those skilled in the art upon reading the foregoing description. Therefore, the scope of the present teachings should be determined not with reference to the foregoing description, but rather with reference to the preceding claims, along with the full scope of equivalents to which such claims are entitled. For the purpose of completeness, all articles and references, including the disclosures of patent applications and publications, are incorporated herein by reference. The omission of any aspect of the subject matter disclosed herein from the preceding claims is not a disclaimer of such subject matter, nor should it be interpreted that the applicants did not consider such subject matter to be part of the disclosed inventive subject matter.

[0051] The above content is a further detailed description of the present invention, and it cannot be considered that the specific implementation methods of the present invention are limited to these. For ordinary technicians in the technical field to which the present invention belongs, they can make several simple deductions or substitutions without departing from the concept of the present invention, which should be regarded as belonging to the determined protection scope of the present invention submitted.

Claims

1. An oil-immersed transformer rapid pressure relief diaphragm driven by electric explosion, characterized in that: It includes a pressure relief plate (1), a base (2), a pressure ring (3), an electric explosion load (4), a limit plate (5), a sealing rubber ring (6), and a wire trough (7); The pressure relief plate (1) is press-fitted onto the base (2) via a pressure ring (3); the middle hole of the base (2), the pressure relief plate (1), and the middle hole of the pressure ring are arranged parallel to each other; the base (2) is mounted on the oil tank of the oil-immersed transformer; and the sealing rubber ring (6) is arranged between the base (2), the side of the pressure relief plate (1) facing the base (2), and the oil tank of the oil-immersed transformer; The electric explosion load (4) includes an inner conductor (8), an outer conductor (9), a flying piece (11) and a soft insulating material (10); the wire groove (7) is opened on the base (2), and a coaxial wire is placed in the wire groove (7); The electric explosion load (4) is a coaxial return structure, the inner conductor (8), the outer conductor (9), and the flying piece (11) are integrally packaged by a soft insulating material (10), and the inner conductor (8) is packaged inside the outer conductor (9) by the soft insulating material (10); the electric explosion load (4) is connected to a power supply via a coaxial wire; The electric explosion load (4) is isolated from the pressure relief plate (1) by a limiting plate (5); a groove is provided on a side of the base (2) facing the pressure relief plate (1); and the electric explosion load (4) is placed on the groove of the base (2); One side of the flying piece (11) has a wedge-shaped blade structure facing the pressure relief piece (1), and the other side of the flying piece (11) faces one side of the outer conductor (9), and the other side of the outer conductor (9) faces the slot of the base (2).

2. The electric explosion-driven oil-immersed transformer rapid pressure relief diaphragm according to claim 1 is characterized in that: The slotted bottom of the base (2) is a parabolic surface, and the inner conductor (8) is located at the parabolic focus of the parabolic surface.

3. The electric explosion-driven oil-immersed transformer rapid pressure relief diaphragm according to claim 1 is characterized in that: The inner conductor (8) is a low-melting-point, high-conductivity conductor, including a metal foil.

4. The electric explosion-driven oil-immersed transformer rapid pressure relief diaphragm according to claim 1 is characterized in that: The electric explosion load (4) is connected to one end of a capacitor via a core wire of a coaxial wire; the high voltage end of the capacitor is grounded, the other end of the capacitor is connected to a power supply, and the sheath wire of the coaxial wire is grounded; When capacitor discharge is used to drive the electric explosion, the length and diameter of the inner conductor (8) are set using the following formula: in, d opt is the inner conductor diameter, l opt is the inner conductor length, L is the circuit inductance, C is the circuit capacitance, U 0 is the capacitor charging voltage, W 0 is the initial capacitor energy storage, ρ 0 is the metal material density of the inner conductor, σ 0 is the conductivity of the inner conductor metal material, λ is the melting specific energy, r is the specific energy of vaporization.

5. The electric explosion-driven oil-immersed transformer rapid pressure relief diaphragm according to claim 1 is characterized in that: The pressure relief piece (1) is provided with a petal-shaped structure to be cut, the pressure ring (3) presses the pressure relief piece (1) onto the base (2) through the petal-shaped structure to be cut, the electric explosion load (4) is placed between the petal-shaped structure to be cut and the slot, and the width of a single petal of the petal-shaped structure to be cut is smaller than the length of the inner conductor (8).

6. The electric explosion-driven oil-immersed transformer rapid pressure relief diaphragm according to claim 5, characterized in that: The number, width and thickness of the petal-shaped structure to be cut are determined by static simulation based on the relationship between the maximum normal oil pressure of the oil tank of the oil-immersed transformer and the yield strength of the material used; The relationship between the maximum normal oil pressure of the oil tank and the yield strength of the material used is: the maximum equivalent stress of the petal-shaped structure to be cut under the maximum normal oil pressure of the oil tank of the oil-immersed transformer is less than half of the yield strength of the material used.

7. The electric explosion-driven oil-immersed transformer rapid pressure relief diaphragm according to claim 6, characterized in that: When the thickness of the petal-shaped structure to be cut of the pressure relief piece (1) reaches 1 mm, the speed of the flying pieces (11) exceeds 150 m / s after the inner conductor (8) is detonated.

8. The electric explosion-driven oil-immersed transformer rapid pressure relief diaphragm according to claim 1, characterized in that: The mass of the flyer (11) is set by the following formula: in, is the quality of the flying piece, is the flying piece speed during electric explosion, W 0 is the initial capacitor energy storage.

9. The electric explosion-driven oil-immersed transformer rapid pressure relief diaphragm according to claim 1, characterized in that: The flying piece (11) is made of high-density and high-hardness material.

10. A method for instantaneously cutting the pressure relief diaphragm of an oil-immersed transformer driven by electric explosion, characterized in that: The method of using the electric explosion-driven oil-immersed transformer rapid pressure relief diaphragm according to any one of claims 1 to 9 comprises the following steps: An external input short-circuit fault signal triggers a pulse power supply to discharge an inner conductor (8) encapsulated in a soft insulating material (10), thereby driving an electric explosion; The high-pressure plasma, metal vapor and shock wave generated by the electric explosion act on the flying piece (11), and the wedge-shaped blade structure of the flying piece (11) hits and cuts off the pressure relief piece (1). The time from the start of the electric explosion to the cutting off of the pressure relief piece (1) is less than 0.2ms, completing the instantaneous cutting of the oil-immersed transformer's rapid pressure relief diaphragm.

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