Multi-stage liquid recoil arc extinguishing device

Abstract

The present invention discloses a multi-stage liquid recoil arc extinguishing device, which belongs to the field of lightning protection arc extinguishing technology, including an inclined recoil device and a vertical sealed arc extinguishing device, wherein the inclined recoil device and the vertical sealed arc extinguishing device are not parallel and not vertically arranged, and the inclined recoil device and the vertical sealed arc extinguishing device are respectively provided with inclined recoil tube insulating liquid and insulating oil, and the insulating oil fills the vertical sealed arc extinguishing device, and the inclined recoil device is arranged obliquely upward. Lightning current is discharged into the earth through an arc extinguishing channel formed by a plurality of ceramic tubes. The air gap between the ceramic tubes prolongs the time for the lightning current to enter the ground, increases the arc residence time in the recoil tube, reduces the damage caused by instantaneous large current to electronic equipment and buildings, increases a plurality of arc break points, implements multi-point synchronous arc interruption for penetrating flashover, divides a long arc into short arcs and extinguishes the short arc units step by step, improves the arc extinguishing ability for a long arc, and effectively suppresses the reignition of the arc.

Description

Technical Field

[0001] The invention relates to the technical field of lightning protection and arc extinguishing, and in particular to a multi-stage liquid recoil arc extinguishing device. Background Art

[0002] The parallel gap has been widely used in lines of various voltage levels due to its simple structure, easy installation and low price. Japan, Germany, France and other countries have begun to study the use of parallel gaps in overhead transmission lines since the 1960s. China has also developed parallel gap lightning protection devices of different voltage levels. However, due to the simple structure of the parallel gap device, the lightning trip rate will increase, and the life of the circuit breaker will be shortened due to frequent load-cutting short-circuit arcs; the parallel gap must be used in conjunction with the automatic reclosing switch to play its protective role. In addition, long-term power frequency arc burning can cause insulator damage and wire breakage, so it is necessary to develop a parallel gap device that can extinguish the arc by itself.

[0003] In view of the defects of ordinary parallel gaps, such as weak self-extinguishing ability, lack of rapid arc extinguishing ability, easy line insulator flashover, large power frequency aftercurrent, and damage to insulator strings and hardware, it is necessary to develop a multi-stage liquid recoil arc extinguishing device. Summary of the invention

[0004] The purpose of the present invention is to provide a multi-stage liquid recoil arc extinguishing device to solve the technical problems that the existing parallel gap has weak self-arc extinguishing ability, lacks rapid arc extinguishing ability, is prone to line insulator flashover, generates large power frequency continuous current, and damages insulator strings and hardware. The present invention uses the energy of the arc itself to heat the gas in the ceramic tube, so that the temperature and pressure in the ceramic tube increase, and then the arc is ejected out of the chamber to avoid the occurrence of lightning tripping. While the arc passes through each recoil tube one by one, the time for the lightning current to release energy is significantly extended, reducing the damage caused by instantaneous large current to electronic equipment and buildings. The gas in the ceramic tube is heated by the energy of the arc itself, so that the temperature and pressure in the ceramic tube increase, and then the arc is ejected out of the chamber and encounters cold air outside to cool and extinguish the arc.

[0005] In order to achieve the above object, the technical solution adopted by the present invention is as follows:

[0006] A multi-stage liquid recoil arc extinguishing device comprises an inclined recoil device and a vertical sealed arc extinguishing device. The inclined recoil device and the vertical sealed arc extinguishing device are not parallel and not vertically arranged. The inclined recoil device and the vertical sealed arc extinguishing device are respectively provided with inclined recoil tube insulating liquid and insulating oil. The insulating oil fills the vertical sealed arc extinguishing device. The inclined recoil device is arranged inclined upward. Metal electrodes are arranged at the inclined recoil device and the vertical sealed arc extinguishing device.

[0007] Furthermore, the inclined recoil device includes an inclined recoil tube, an inclined recoil tube bottom electrode and an insulating material, wherein the inclined recoil tube bottom electrode is arranged at the bottom of the inclined recoil tube and is grounded, the other open end of the inclined recoil tube is arranged on a metal electrode, and an insulating material is arranged between the metal electrode and the inclined recoil tube bottom electrode), and the insulating material is wrapped around the outside of the inclined recoil tube.

[0008] Furthermore, the vertical sealed arc extinguishing device includes one or more vertical sealed arc extinguishing barrels, and the plurality of vertical sealed arc extinguishing barrels are arranged end to end and arranged on the same vertical line, and the bottom of the lowest vertical sealed arc extinguishing barrel is grounded.

[0009] Furthermore, the vertical sealed arc extinguishing barrel includes a metal plate, a sealed tube, and a sealed tube bottom electrode. The metal plate is sealed at the top of the sealed tube, the sealed tube bottom electrode is sealed at the bottom of the sealed tube, and insulating oil fills the internal space of the sealed tube.

[0010] Furthermore, metal rods are arranged on the metal plate and the bottom electrode of the sealed tube, the two metal rods are arranged opposite to each other and not in contact with each other, and insulating oil is filled between the two metal rods.

[0011] Furthermore, the length of the two metal rods is less than half of the length of the sealing tube.

[0012] Furthermore, the arc extinguishing process is divided into four steps. Step 1: When lightning strikes a pole tower or a transmission line, the arc infusion stage causes the Pascal effect. When the lightning arc is infused into the interior of the sealed tube, the arc diameter becomes thinner and axial pressure is generated at the same time. After any point in the incompressible static fluid is subjected to an external force and the pressure increase is generated, the pressure increase is transmitted to each point of the static fluid in an instant. Then, during the arc infusion stage, the pressure change in the sealed tube will be transmitted in all directions without changing its size, causing the pressure in the sealed tube to further increase. Then, the reaction force impacts the center, impacting the arc with a greater force, thereby achieving the purpose of cutting off the arc.

[0013] Step 2: After the pre-breakdown occurs, the arc pre-breakdown causes a liquid-electric effect, and an arc is formed between the iron rods in the sealed tube. The arc discharges in the sealed tube containing insulating oil. Part of the liquid in the discharge channel is instantly vaporized, decomposed, and ionized into a high-temperature plasma, which suddenly expands, forming a mechanical pressure wave that propagates outward. However, since the liquid can be regarded as a shock wave transmission medium that will not be compressed itself, when liquid phase discharge is carried out in the discharge channel, it exhibits an ultra-high power mechanical effect to the outside world, forming an impact force in the ceramic tube, acting on the discharge channel in the form of impulse or impact pressure, impacting the arc and cutting it off;

[0014] The residual energy forms an arc in the inclined recoil tube 1 through the metal electrode. When the arc enters the inclined recoil tube 1 containing liquid, the plasma temperature generated by the liquid phase discharge is as high as 1500-3000K. The high temperature and high pressure generated in the ceramic tube cannot leak out in time. The shock wave reflects back and forth on the inner wall of the ceramic tube, generating a reflected shock wave that is ejected from the arc entrance.

[0015] Step 3: The length of the ceramic tube is 50mm and the diameter is 10mm. The arc formed in the ceramic tube after the lightning strike is long enough. The principle of recoil is to use the energy of the long arc itself to extinguish the arc. The longer the arc formed in the ceramic tube, the more obvious the Pascal effect, the greater the pressure in the ceramic tube, and the greater the impact force of cutting off the arc.

[0016] Step 3: When the lightning current pulse is injected into the metal rod, the liquid phase discharge of the metal material generates a shock wave. Under the action of Joule heat, part of the metal material on the metal rod is vaporized, decomposed, and ionized into high-temperature plasma, and finally develops into a plasma channel. Since the impact time of the lightning pulse is extremely short, the insulating oil in the ceramic tube cannot deform and displace instantaneously. Under the action of the liquid-electric effect, a pressure of about 100Mpa is generated inside the ceramic tube, generating a shock wave to cut off the arc.

[0017] The present invention has the following beneficial effects due to the adoption of the above technical solution:

[0018] The lightning current of the present invention is discharged into the earth through arc extinguishing channels formed by multiple ceramic tubes. The air gap between the ceramic tubes prolongs the time for the lightning current to enter the ground, increases the arc residence time in the recoil tube, reduces the damage caused by instantaneous large current to electronic equipment and buildings, increases multiple arc break points, implements multi-point synchronous arc interruption for penetrating flashover, divides the long arc into short arcs and extinguishes the short arc units step by step, improves the arc extinguishing ability for the long arc, and effectively inhibits the reignition of the arc. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of the structure of the present invention.

[0020] Figure 2 This is a schematic diagram of the high-pressure sealing structure of the sealing tube of the present invention;

[0021] Figure 3 It is a schematic diagram of the external reinforcement structure of the sealing tube of the present invention.

[0022] In the accompanying drawings, 1-inclined recoil tube, 2-inclined recoil tube bottom electrode, 3-inclined recoil tube insulating liquid, 4-insulating material, 5-metal electrode, 6-metal plate, 7-sealed tube, 8-sealed tube bottom electrode, 9-metal rod, 10-insulating oil. DETAILED DESCRIPTION

[0023] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and preferred embodiments. However, it should be noted that many details listed in the specification are only for the purpose of enabling the reader to have a thorough understanding of one or more aspects of the present invention, and these aspects of the present invention can be implemented even without these specific details.

[0024] like Figure 1 As shown, a multi-stage liquid recoil arc extinguishing device includes an inclined recoil device and a vertical sealed arc extinguishing device. The inclined recoil device and the vertical sealed arc extinguishing device are not parallel and not vertically arranged. The inclined recoil device and the vertical sealed arc extinguishing device are respectively provided with an inclined recoil tube insulating liquid 3 and an insulating oil 10. The insulating oil 10 fills the vertical sealed arc extinguishing device. The inclined recoil device is arranged obliquely upward. Metal electrodes 5 are arranged at the inclined recoil device and the vertical sealed arc extinguishing device. The vertical sealed arc extinguishing device forms a Pascal effect. When an arc is formed, due to the closed structure, the arc will squeeze the liquid, causing the liquid to generate outward pressure. Then, due to the side wall, the force is recoiled back, and the force is directly directed to the arc in the center, which can quickly extinguish the arc.

[0025] In the embodiment of the present invention, the inclined recoil device includes an inclined recoil tube 1, an inclined recoil tube bottom electrode 2 and an insulating material 4. The inclined recoil tube bottom electrode 2 is arranged at the bottom of the inclined recoil tube 1 and is grounded. The other open end of the inclined recoil tube 1 is arranged on a metal electrode 5. An insulating material 4 is arranged between the metal electrode 5 and the inclined recoil tube bottom electrode 2. The insulating material 4 is wrapped around the outer side of the inclined recoil tube 1. The inclined recoil device first performs recoil arc extinguishing on the upper end of the arc, and at the same time, the arc is introduced through two lines, so that the arc becomes smaller and extinguished better. One is recoil arc extinguishing, and the other is sealed arc extinguishing, which has a faster effect and can extinguish higher voltage arcs.

[0026] In the embodiment of the present invention, the vertical sealed arc extinguishing device includes one or more vertical sealed arc extinguishing barrels, and the plurality of vertical sealed arc extinguishing barrels are arranged end to end and arranged on the same vertical line, and the bottom of the lowest vertical sealed arc extinguishing barrel is grounded.

[0027] In an embodiment of the present invention, the vertical sealed arc extinguishing barrel includes a metal plate 6, a sealed tube 7, and a sealed tube bottom electrode 8. The metal plate 6 is sealed at the top of the sealed tube 7, the sealed tube bottom electrode 8 is sealed at the bottom of the sealed tube 7, and the insulating oil 10 fills the internal space of the sealed tube 7.

[0028] In the embodiment of the present invention, metal rods 9 are disposed on the metal plate 6 and the bottom electrode 8 of the sealed tube, the two metal rods 9 are disposed opposite to each other and not in contact, and insulating oil 10 is filled between the two metal rods 9. The length of the two metal rods 9 is less than half of the length of the sealed tube 7.

[0029] The ceramic tube is cylindrical, in which the sealing tube 7 is placed vertically, the inside of the ceramic tube is filled with insulating oil, and the upper and lower ends of the sealing tube 7 are sealed with cylindrical metal plates, and there is a thick metal rod immersed in the insulating oil in the center of the upper and lower metal plates; a metal electrode is provided at the upper end of the inclined recoil tube 1, and there is a certain angle between the sealing tube 7 and the inclined recoil tube 1, and they are connected with a metal electrode; the lower end of the inclined recoil tube 1 is connected to the ground end through a metal electrode.

[0030] The ceramic tube is cylindrical, in which the sealing tube 7 is placed vertically, the inside of the ceramic tube is filled with insulating oil, and the upper and lower ends of the sealing tube 7 are sealed with cylindrical metal plates, and there is a metal rod immersed in the insulating oil in the center of the upper and lower metal plates; a metal electrode is provided at the upper end of the inclined recoil tube 1, and there is a certain angle between the sealing tube 7 and the inclined recoil tube 1, and they are connected with a metal electrode; the lower end of the inclined recoil tube 1 is connected to the ground end through a metal electrode.

[0031] When lightning strikes a pole tower or a transmission line, an arc will be formed in a ceramic tube filled with insulating oil, generating a hydroelectric effect and forming a powerful shock wave, which acts on the discharge channel in the form of impulse or impact pressure to cut off the arc. The ceramic tube is made of inorganic non-metallic materials with high hardness, high temperature resistance and high pressure resistance. The space inside the ceramic tube is the main area where arc extinguishing occurs. At the same time, when lightning strikes a metal electrode, the arc discharges in the sealed tube 7, causing the Pascal effect, causing the pressure in the sealed tube 7 to further increase, and impacting the arc in the sealed tube 7 with a greater force.

[0032] The remaining energy is transferred from the sealed tube 7 to the inclined recoil tube 1 through the metal electrode. The arc discharges in the inclined recoil tube 1 filled with liquid, which will cause the superposition of the Pascal effect and the liquid-electric effect, forming a strong shock wave, which acts on the discharge channel in the form of impulse or impact pressure to cut off the arc. The remaining little energy is grounded through the grounding terminal.

[0033] The Pascal effect is caused during the arc injection stage: when lightning strikes a tower or a transmission line, the lightning arc is injected into the interior of the sealed tube 7, and the arc diameter becomes thinner and axial pressure is generated at the same time; according to the Pascal principle: "When any point in an incompressible static fluid generates a pressure increase due to an external force, this pressure increase is instantly transmitted to all points in the static fluid". During the arc injection stage, the pressure change in a certain part of the sealed tube 7 will be transmitted in all directions without changing its size, causing the pressure in the sealed tube 7 to further increase, impacting the arc with a greater force, thereby achieving the purpose of cutting off the arc.

[0034] The arc pre-breakdown causes the liquid-electric effect: after the pre-breakdown occurs, an arc is formed between the iron rods in the sealed tube 7, and the arc discharges in the sealed tube 7 containing insulating oil. Part of the liquid in the discharge channel is instantly vaporized, decomposed, and ionized into high-temperature plasma, which suddenly expands, forming a mechanical pressure wave that propagates rapidly outward. However, since the liquid can be regarded as a shock wave transmission medium that will not be compressed by itself, when the liquid phase discharge is carried out in the discharge channel, it shows an ultra-high power mechanical effect to the outside world, forming an impact force in the ceramic tube, acting on the discharge channel in the form of impulse or impact pressure, impacting the arc and cutting it off.

[0035] The residual energy forms an arc in the inclined recoil tube 1 through the metal electrode. When the arc enters the inclined recoil tube 1 containing liquid, the plasma temperature generated by the liquid phase discharge is as high as 1500-3000K. The high temperature and high pressure generated in the ceramic tube cannot leak out in time. The shock wave reflects back and forth on the inner wall of the ceramic tube, generating a reflected shock wave that is ejected from the arc entrance.

[0036] The energy of the long arc in the ceramic tube is large, and the recoil force is also large: the length of the ceramic tube is 50mm and the diameter is 10mm, so the length of the arc formed in the ceramic tube after the lightning strike is long enough. The principle of recoil is to use the energy of the long arc itself to extinguish the arc. The longer the arc formed in the ceramic tube, the more obvious the Pascal effect, the greater the pressure in the ceramic tube, and the greater the impact force of cutting off the arc.

[0037] Liquid phase discharge of metal materials generates shock waves: When the lightning current pulse is injected into the metal rod, under the action of Joule heat, part of the metal material on the metal rod vaporizes, decomposes, and ionizes into high-temperature plasma, and finally develops into a plasma channel. Since the impact time of the lightning pulse is extremely short, the insulating oil in the ceramic tube cannot deform and displace instantly. Under the action of the liquid-electric effect, the ceramic tube generates a pressure of about 100Mpa, generating a shock wave to cut off the arc.

[0038] A high-pressure sealing structure and an external reinforcement structure are arranged inside the sealing tube 7 .

[0039] The high-pressure sealing structure includes a plastic sleeve 21, a stainless steel gasket 22, an O-ring 23, a steel sleeve 24, a sealing silicone 25 and an extrusion fixing block 26. The electrode is nested in the sealing silicone 25. The sealing silicone 25 is sealed at both ends of the ceramic tube. The steel sleeve 24 is fastened to the outside of the connection between the sealing silicone 25 and the ceramic tube. The plastic sleeve 21 is sleeved on the outside of the steel sleeve 24 and the ceramic tube. The stainless steel gasket 22 is padded at the front end of the electrode, and the O-ring 23 is arranged between the contact between the sealing silicone 25 and the ceramic tube. The extrusion fixing block 26 is arranged on the outside of the sealing silicone 25, and a bolt hole 27 is arranged on the extrusion fixing block 26. The bolt hole 27 is arranged in contact with the stainless steel gasket 22. The sealing silicone 25 is set as a "T"-shaped structural silicone, and the bottom of the "T"-shaped structural silicone is set as a spherical concave structure.

[0040] The shell is made of plastic insulating material to fix the ceramic tube; the steel sleeve is installed at both ends of the ceramic tube to fix the ends of the ceramic tube to prevent the high-intensity pressure from mechanically deforming the ceramic tube; the semi-arc-shaped silicone wraps the upper and lower electrodes. When the upper and lower electrodes extinguish the arc, the narrow space and small area produce pressure dispersion. The semi-arc-shaped silicone wraps the electrodes to focus the pressure wave, increase the pressure of the arc extinguishing channel by several times, and effectively block the arc. The screw generates thrust to the stainless steel gasket and silicone assembly, so that it cooperates closely with the O-ring and the ceramic tube to achieve the purpose of high-pressure sealing, which well prevents the leakage of high-intensity pressure and can ensure that the generated high-intensity pressure acts on the arc to the maximum extent.

[0041] When the device is struck by lightning, a liquid-electric effect is generated, forming a strong shock pressure wave, which acts on the discharge channel in the form of impulse or shock pressure to cut off the arc. At the same time, a certain pressure is applied to the arc-extinguishing liquid in the ceramic tube. According to Pascal's principle, the pressure change of a part of the static fluid in the closed container will be transmitted in all directions without changing the size, which will inevitably produce a greater force on the inner wall of the ceramic tube. This force rebounds after acting on the outer shell, forming a force pointing to the center of the ceramic tube, so as to cut off the arc, reduce the amplitude of the current, reduce the steepness of the lightning wave, and prolong the discharge time of the arc. It effectively extinguishes the arc, has a simple structure, and has good sealing performance.

[0042] The external reinforcement structure includes a top cover plate 31, an insulating screw 33, a bottom cover plate 34 and an insulating covering layer 35. The top cover plate 31 is arranged at the top of the high-voltage sealing device, the bottom cover plate 34 is arranged at the bottom of the high-voltage sealing device, the insulating screw 33 passes through the top cover plate 31 and the bottom cover plate 34 and is fixedly arranged, the insulating covering layer 35 is arranged on the outside of the high-voltage sealing device, the top cover plate 31 and the bottom cover plate 34 respectively support the extrusion fixing block 26, and the top cover plate 31 and the bottom cover plate 34 are provided with screw holes. The fixing effect is better, so that the entire arc extinguishing device can withstand greater pressure.

[0043] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. Multi-stage liquid recoil arc extinguishing device, characterized in that: The invention comprises an inclined recoil device and a vertical sealed arc extinguishing device, wherein the inclined recoil device and the vertical sealed arc extinguishing device are not parallel and are not vertically arranged, and the inclined recoil device and the vertical sealed arc extinguishing device are respectively provided with an inclined recoil tube insulating liquid (3) and insulating oil (10), and the insulating oil (10) fills the vertical sealed arc extinguishing device, the inclined recoil device is arranged obliquely upward, and metal electrodes (5) are arranged at the inclined recoil device and the vertical sealed arc extinguishing device; A metal rod (9) is disposed on the metal plate (6) and the bottom electrode (8) of the sealed tube. The two metal rods (9) are disposed opposite to each other and are not in contact with each other. Insulating oil (10) is filled between the two metal rods (9). The length of the two metal rods (9) is less than half of the length of the sealing tube (7); The arc extinguishing process is divided into four steps. Step 1: When lightning strikes a pole tower or a transmission line, the Pascal effect is caused during the arc injection stage. When the lightning arc is injected into the interior of the sealed tube (7), the arc diameter becomes thinner and axial pressure is generated. After any point in the incompressible static fluid is subjected to an external force and the pressure increase is generated, the pressure increase is transmitted to each point of the static fluid in an instant. During the arc injection stage, the pressure change that occurs in the sealed tube (7) is transmitted in all directions without changing its size, causing the pressure in the sealed tube (7) to further increase. Then, the reaction force impacts the center, impacting the arc with a greater force, thereby achieving the purpose of cutting off the arc. Step 2: After the pre-breakdown occurs, the arc pre-breakdown causes a liquid-electric effect, and an arc is formed between the iron rods in the sealed tube (7). The arc discharges in the sealed tube (7) containing insulating oil, and part of the liquid in the discharge channel is instantly vaporized, decomposed, and ionized into a high-temperature plasma, which suddenly expands, forming a mechanical pressure wave that propagates outward. However, since the liquid can be regarded as a shock wave transmission medium that cannot be compressed itself, when liquid phase discharge is carried out in the discharge channel, it exhibits an ultra-high power mechanical effect to the outside world, and forms an impact force in the ceramic tube, which acts on the discharge channel in the form of impulse or impact pressure, impacting the arc and cutting it off; The residual energy forms an arc in the inclined recoil tube (1) through the metal electrode. When the arc enters the inclined recoil tube (1) containing liquid, the plasma temperature generated by the liquid phase discharge is as high as 1500-3000K. The high temperature and high pressure generated in the ceramic tube cannot leak out in time. The shock wave is reflected back and forth on the inner wall surface of the ceramic tube, generating a reflected shock wave, which is ejected from the arc entrance. Step 3: The length of the ceramic tube is 50mm and the diameter is 10mm. The arc formed in the ceramic tube after the lightning strike is long enough. The principle of recoil is to use the energy of the long arc itself to extinguish the arc. The longer the arc formed in the ceramic tube, the more obvious the Pascal effect, the greater the pressure in the ceramic tube, and the greater the impact force of cutting off the arc. Step 4: When the lightning current pulse is injected into the metal rod, the liquid phase discharge of the metal material generates a shock wave. Under the action of Joule heat, part of the metal material on the metal rod is vaporized, decomposed, and ionized into high-temperature plasma, and finally develops into a plasma channel. Since the impact time of the lightning pulse is extremely short, the insulating oil in the ceramic tube cannot deform and displace instantaneously. Under the action of the liquid-electric effect, a pressure of about 100Mpa is generated inside the ceramic tube, generating a shock wave to cut off the arc.

2. The multi-stage liquid recoil arc extinguishing device according to claim 1, characterized in that: The inclined recoil device comprises an inclined recoil tube (1), an inclined recoil tube bottom electrode (2) and an insulating material (4); the inclined recoil tube bottom electrode (2) is arranged at the bottom of the inclined recoil tube (1) and is grounded; the other open end of the inclined recoil tube (1) is arranged on a metal electrode (5); an insulating material (4) is arranged between the metal electrode (5) and the inclined recoil tube bottom electrode (2); and the insulating material (4) is wrapped around the outer side of the inclined recoil tube (1).

3. The multi-stage liquid recoil arc extinguishing device according to claim 1, characterized in that: The vertical sealed arc extinguishing device comprises one or more vertical sealed arc extinguishing barrels, wherein several vertical sealed arc extinguishing barrels are arranged end to end and arranged on the same vertical line, and the bottom of the lowest vertical sealed arc extinguishing barrel is grounded.

4. The multi-stage liquid recoil arc extinguishing device according to claim 3, characterized in that: The vertical sealed arc extinguishing barrel comprises a metal plate (6), a sealed tube (7), and a sealed tube bottom electrode (8); the metal plate (6) is sealed at the top of the sealed tube (7); the sealed tube bottom electrode (8) is sealed at the bottom of the sealed tube (7); and the insulating oil (10) fills the internal space of the sealed tube (7).

Images