An arc extinguishing device for insulator modification to cope with insulation coordination failure

Abstract

The present invention discloses an arc extinguishing device for insulator modification to cope with insulation coordination failure, which belongs to the field of construction and includes an insulator string, an upper cross arm and a lower cross arm, wherein the insulator string is arranged between the upper cross arm and the lower cross arm. An upper sealed arc extinguishing unit is arranged at the bottom of the upper cross arm, and a lower sealed arc extinguishing unit is arranged at the upper end of the lower cross arm. The upper sealed arc extinguishing unit and the lower sealed arc extinguishing unit are arranged opposite to each other, and the upper sealed arc extinguishing unit and the lower sealed arc extinguishing unit are arranged on the side of the insulator string and are not arranged in contact with the insulator string. The present invention cuts off the arc quickly, and the arc discharges in the liquid to generate a liquid-electric effect, quickly forming an impact pressure wave, and the lightning impact arc is immediately cut off at the initial stage of establishment. It has a rapid reaction speed and has the characteristics that when the arc power is maximum and the energy is maximum, the recoil energy generated is also maximum.

Description

Technical Field

[0001] The invention relates to the technical field of arc extinguishing, and in particular to an insulator modification arc extinguishing device for coping with insulation coordination failure. Background Art

[0002] Lightning strikes can cause various forms of damage and destruction to power facilities. Thundercloud discharges can cause lightning overvoltage in power systems. Lightning overvoltage can damage insulators and transmission lines. When lightning strikes a transmission line, the impulse flashover causes line insulator flashover, which in turn generates a large power frequency follow-current, damaging insulator strings and hardware, leading to line accidents. When lightning strikes a transmission line or lightning arrester, it may cause strand breakage or even fracture, making it impossible to carry out power transmission work.

[0003] The existing lightning protection arc extinguishing device can make the volt-second characteristic of the active arc extinguishing parallel gap flatter, but the existing lightning protection arc extinguishing device can only reduce the steepness of the wave head of the lightning current and cannot further attenuate the amplitude of the lightning current, and the ability to attenuate the lightning current is limited.

[0004] Secondly, the existing connection method between the lightning protection arc extinguishing device and the insulator is insufficient, and it cannot protect the insulator well and give full play to the role of the lightning protection device. In addition, in many cases, there are problems such as surface flashover of the insulator, and insulation coordination due to natural external forces, aging reduces the equivalent distance, and insulator deformation due to moisture, which makes the coordination between the insulator and the traditional lightning protection gap ineffective, causing the lightning overvoltage to be released not through the protection gap, but through surface discharge and other methods, thereby damaging the insulator and surrounding power transmission and distribution equipment, and even causing secondary damage such as counterattack and winding failure.

[0005] Finally, according to the requirements of the country's sustainable development and environmental protection policies, traditional lightning protection methods have excessive carbon emissions, and the protection of insulators by new lightning protection devices is achieved through the technical route of reducing the amplitude of lightning current. It can reduce the heat generation of insulating devices such as valve plates and insulators, reduce heat loss of insulating parts, extend the service life of equipment, and reduce carbon generation during the lightning protection arc extinguishing action of the device, thereby reducing carbon emissions and being more environmentally friendly and sustainable. Summary of the invention

[0006] The purpose of the present invention is to provide an arc extinguishing device for insulator modification to cope with insulation coordination failure, and to solve the technical problem of surface flashover of insulators due to various reasons in the case of existing insulation coordination failure. It can respond promptly and quickly in the early stage of arc building to form arc extinguishing pressure. The arc extinguishing pressure peak value is highly consistent with the arc energy impact peak time curve, which converts the rapid lightning current discharge process and large impact amplitude into intermittent discharge and quickly cuts off the arc. It is miniaturized and installed near the metal crossarm fixing hardware of the insulator, fixed at the parallel position where the metal part of the insulator is close to the upper and lower insulating material filled long rods, forming a smaller protective gap to prevent surface flashover of the insulator.

[0007] In order to achieve the above object, the technical solution adopted by the present invention is as follows:

[0008] An insulator retrofit arc extinguishing device for dealing with insulation coordination failure comprises an insulator string, an upper cross arm and a lower cross arm, wherein the insulator string is arranged between the upper cross arm and the lower cross arm. An upper sealed arc extinguishing unit is arranged at the bottom of the upper cross arm, and a lower sealed arc extinguishing unit is arranged at the upper end of the lower cross arm. The upper sealed arc extinguishing unit is arranged opposite to the lower sealed arc extinguishing unit, and the upper sealed arc extinguishing unit and the lower sealed arc extinguishing unit are arranged at the side of the insulator string and are not in contact with the insulator string.

[0009] A recoil arc extinguishing unit is arranged at the bottom of the upper sealed arc extinguishing unit and the upper end of the lower sealed arc extinguishing unit. The recoil arc extinguishing unit includes a lightning electrode, a recoil tube body, a recoil tube skirt, and a bottom lightning electrode. The lightning electrode is arranged at the top of the recoil tube body, the recoil tube skirt is arranged at the side of the recoil tube body, the recoil tube body is arranged inside with a recoil hole, and the lower end of the recoil hole is arranged with a bottom lightning electrode, and the lightning electrode and the bottom lightning electrode are both graphite electrodes.

[0010] Furthermore, the upper sealed arc extinguishing unit and the lower sealed arc extinguishing unit are both configured as a sealed tube, upper electrode and lower electrode sealing devices are respectively provided at both ends of the sealed tube, insulating oil is provided in the sealed tube, and a skirt is provided on the side of the sealed tube.

[0011] Furthermore, the sealing tube also includes a ceramic tube and a protective shell, the protective shell is arranged on the outside of the ceramic tube, and the skirt is arranged on the outside of the protective shell.

[0012] Furthermore, the upper electrode includes an upper graphite electrode, an intermediate metal electrode and a lower graphite electrode, the intermediate metal electrode is fixed at one end of the ceramic tube and the protective shell, the upper graphite electrode is arranged on the upper layer of the intermediate metal electrode, the lower graphite electrode is arranged at the bottom of the intermediate metal electrode and is arranged in the ceramic tube, and the lower electrode includes an upper graphite electrode and a bottom metal electrode, the bottom metal electrode is fixed at the other end of the ceramic tube and the protective shell, the upper graphite electrode is arranged in the ceramic tube and is connected to the bottom metal electrode.

[0013] Furthermore, the upper sealed arc extinguishing unit and the lower sealed arc extinguishing unit are both configured as a sealed tube, upper electrode and lower electrode sealing arrangements are respectively arranged at both ends of the sealed tube, insulating oil is arranged in the sealed tube, a skirt is arranged on the side of the sealed tube, arc extinguishing grids are arranged at intervals on the inner side of the sealed tube, and the lateral length of the arc extinguishing grid is greater than half of the inner diameter of the sealed tube.

[0014] Furthermore, an upper tip electrode is arranged at the bottom of the upper electrode, a lower tip electrode is arranged at the upper end of the lower electrode, the upper tip electrode and the lower tip electrode are relatively vertically arranged, and both the upper tip electrode and the lower tip electrode are graphite electrodes.

[0015] Furthermore, the arc extinguishing grid is made of insulating material, and the arc extinguishing grid is arranged as a semicircular structure. The arc extinguishing grids arranged on the inner walls of the two semicircles in the sealing tube are arranged alternately, and convex piers are arranged between the arc extinguishing grids on the same semicircle, and the convex piers on the inner wall of one semicircle are arranged opposite to the arc extinguishing grid on the inner wall of the other semicircle.

[0016] The liquid-electric effect generates shock waves: arc discharge is triggered in a ceramic tube filled with liquid, and 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 itself, when liquid phase discharge is carried out in the discharge channel, it exhibits an ultra-high-power mechanical effect to the outside world. At the beginning of arc construction, a force that impacts the ceramic tube wall is formed in the ceramic tube. This impact force reaches a peak value when the arc is pre-broken, and the arc extinguishing response time is extremely short. Due to the mutuality of force, the ceramic tube wall generates a strong shock wave in the liquid medium, which acts on the discharge channel in the form of impulse or impact pressure, impacting the arc and cutting it off.

[0017] The Pascal effect further enhances the hydroelectric effect: Pascal's principle states that "when any point in an incompressible static fluid is subjected to an external force and the pressure increases, this pressure increase is instantly transmitted to all points in the static fluid", that is, the pressure is equal to the applied pressure divided by the area under force.

[0018] When the impact arc acts on the metal electrode, a certain pressure is applied to the liquid in the ceramic tube. According to Pascal's principle, the pressure change of a part of the static fluid in a closed container will be transmitted in all directions without changing in size. Starting from the discharge channel in the ceramic tube, the surrounding liquid medium is impacted with a greater force. After hitting the ceramic tube wall, the force rebounds, forming a force pointing to the center of the ceramic tube, further enhancing the impact pressure generated in the liquid-electric effect, and achieving the purpose of cutting off the arc. And the longer the arc formed in the ceramic tube, the greater the force on the ceramic tube wall, and conversely the greater the impact force to cut off the arc. Considering that the arc action time is short, its effect instantly forms a strong recoil pressure to act back on the arc itself, and the current of the arc is weak in the initial stage of arc construction, and the electric field force formed by self-magnetic compression to maintain the arc is small, thus forming a huge impact force far exceeding the pressure of the arc-maintaining Lorentz force, instantly cutting off the arc.

[0019] Coulomb force: Before the arc breaks down, there is a strong electric field in the atmosphere. Before the plasma composed of the arc and the micro electron collapse generated by the strong electric field is about to be injected into the narrow recoil tube, the external plasma and arc are electrically neutral. However, when the arc moves into the tube and collides with the positive ion group induced in the tube, it can be considered that a unipolar charge is injected into the entire plasma, thus meeting the conditions of the Debye screening effect. Considering the radius of the Debye screening effect, the plasma in the tube cannot maintain electrical neutrality. Therefore, the Debye effect cannot be maintained and the external potential cannot be shielded. Therefore, it is quickly recoiled under the action of the external strong electric field.

[0020] The recoil triggers Langmuir oscillation of the plasma, causing the negative electron groups affected by the strong electric field to oscillate back and forth under the action of the electric field, forming a strong oscillating current. Therefore, the arc current cannot increase rapidly, but instead produces fluctuations and oscillations, thereby achieving effective attenuation of the arc current.

[0021] The pressure peak time is during the pre-breakdown time. Whether it is impact or power frequency strobe, the maximum change rate time is during the pre-breakdown time. The maximum change rate will inevitably produce the maximum arc occupation volume change rate. At the same time, the liquid has the characteristic of not allowing arc occupation due to its incompressibility, thus generating a pressure peak. At the same time, the arc current is extremely weak, and the arc anti-interruption pressure is extremely small, forming an asymmetric advantage of arc extinguishing pressure.

[0022] The rapid arc extinguishing capability produces an intermittent discharge mode. The frequent arc extinguishing and frequent reignition mechanism suppresses the arc intensity and prolongs the arc duration, causing the discharge intensity and steepness to decay significantly at the same time, thereby reducing the intensity of destructive energy release to avoid the safety, durability and reliability of the lightning protection device.

[0023] Strongly polarized media will generate polarization current in the impact pre-breakdown stage, which reduces the breakdown voltage, which is equivalent to reducing the breakdown voltage value corresponding to a short period of time, making the corresponding breakdown volt-second characteristic of the water medium smoother, reducing the breakdown starting voltage while also reducing the residual voltage value.

[0024] The present invention has the following beneficial effects due to the adoption of the above technical solution:

[0025] (1) The present invention cuts off the arc quickly. The arc discharges in the liquid to generate a liquid-electric effect, quickly forming an impact pressure wave, and the lightning impact arc is immediately cut off at the initial stage of its establishment. It has a rapid reaction speed and has the following characteristics: when the arc power is at its maximum and the energy is at its maximum, the recoil energy generated is also at its maximum.

[0026] (2) The reignition of the impulse arc is delayed. The high voltage in the ceramic tube destroys the continuous discharge conditions and the reignition conditions. After the impulse arc is cut off, the reignition breakdown time is greatly delayed by more than ten to tens of microseconds, and the instantaneous impulse discharge of the arc is transformed into an intermittent discharge mode, so that the impulse current cannot suddenly increase. The steepness of the lightning current is significantly reduced by 90%, and the current amplitude is attenuated by more than 50%.

[0027] (3) Better protection for insulators. By providing a new insurance strategy for insulator coordination failure, it undoubtedly greatly enhances the safety and integrity of insulators in the event of a fault, thereby further protecting the insulators themselves. It has a better protection effect.

[0028] (4) It can play an insurance role in the case of insulation coordination failure. Compared with traditional insulation coordination, the patent of this invention focuses on considering the failure of external insulation coordination and the protection measures for insulators in the case of accidental flashover of insulators in various situations, so that the accidental flashover becomes the flashover inside the device, thereby extinguishing the arc, reducing the intensity and amplitude of the accidental flashover overvoltage and overcurrent, and further protecting the insulator. By reasonably adjusting the gear spacing and the liquid lightning protection gap, the device can make the external overvoltage enter the arc extinguishing channel first, thereby achieving the purpose of extinguishing the arc and protecting the insulator.

[0029] (5) Avoid electromagnetic induction overvoltage from damaging equipment. During lightning discharge, a transient strong electromagnetic field is generated in the space around the discharge channel, generating a higher electromagnetic induction electromotive force that interferes with signal lines and even damages equipment. The arc extinguishing method based on the Pascal principle cuts off the arc through the recoil force, extending the arc discharge time by hundreds or thousands of times, making the arc rise more gently, thereby reducing the steepness of the lightning wave. This avoids the harm of induced electromagnetic overvoltage to power electronic components, communication signals, etc.

[0030] (6) Reduce carbon emissions caused by lightning damage. The technical route adopted by the new lightning protection device can effectively attenuate the intensity of lightning strikes, thereby reducing the damage to insulators caused by direct lightning strikes. First, it can prevent the lightning path from being built in the insulator, generating a large amount of heat loss, thereby increasing carbon emissions and reducing the life of the insulator. Second, it reduces the intensity of lightning, thereby reducing the large amount of carbon emissions originally caused by lightning damage. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a schematic diagram of the structure of the device of the present invention;

[0032] Figure 2 This is a schematic diagram of the structure of the first sealed arc extinguishing unit of the present invention;

[0033] Figure 3 It is a schematic diagram of the structure of the second sealed arc extinguishing unit of the present invention;

[0034] Figure 4 It is a schematic diagram of the high-pressure sealing structure of the sealed arc extinguishing unit of the present invention;

[0035] Figure 5 It is a schematic diagram of the external reinforcement structure of the sealed arc extinguishing unit of the present invention.

[0036] In the accompanying drawings, A-upper sealed arc extinguishing unit, B-lower sealed arc extinguishing unit, C-insulator string, D-upper cross arm, E-lower cross arm, 1-upper electrode, 2-insulating oil, 3-ceramic tube, 4-skirt, 5-protective casing, 6-lower electrode, 7-arc, 8-upper tip electrode, 9-arc extinguishing grid, 10-convex pier, 11-lower tip electrode. DETAILED DESCRIPTION

[0037] 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.

[0038] Embodiment 1:

[0039] like Figure 1-2 As shown, an insulator retrofit arc extinguishing device for coping with insulation coordination failure includes an insulator string C, an upper cross arm D and a lower cross arm E, wherein the insulator string C is arranged between the upper cross arm D and the lower cross arm E. An upper sealed arc extinguishing unit A is arranged at the bottom of the upper cross arm D, and a lower sealed arc extinguishing unit B is arranged at the upper end of the lower cross arm E. The upper sealed arc extinguishing unit A and the lower sealed arc extinguishing unit B are arranged opposite to each other, and the upper sealed arc extinguishing unit A and the lower sealed arc extinguishing unit B are arranged at the side of the insulator string C and are not in contact with the insulator string C.

[0040] The specific installation conditions of this device are as follows Figure 1 As shown. The right side is an enlarged view of the structure, and the left side is a view of the actual installation effect. It mainly protects the insulator from damage to the insulator due to surface discharge. It is constructed between the cross arm and the insulator insulation body to form a priority discharge protection. In order to cope with the surface discharge of the insulator under higher voltage levels, an umbrella skirt is added at the connection between the metal fixed part and the insulating material part of the insulator, and a liquid lightning protection arc extinguishing device is suspended in parallel here to increase its surface creepage distance. Without increasing the suspension distance, it makes it easier for the lightning overcurrent to select the arc extinguishing channel, thereby better protecting the insulator and preventing surface discharge.

[0041] Considering the higher level and installation condition restrictions, the design adds a shed between the metal and insulation material of the upper and lower cylinders of the insulator. This method aims to provide non-exposed surface discharge protection for the insulator string, increase the arc creepage distance, and provide double protection with the lightning protection and arc extinguishing device suspended in parallel, which is safer and more reliable.

[0042] During the operation, the lightning protection arc extinguishing device first attracts lightning to strike the upper conductive level, and the voltage drop borne by the insulator is the same as that of the lightning protection arc extinguishing gap. Once the voltage at both ends of the lightning protection arc extinguishing gap exceeds a certain threshold, a discharge arc extinguishing effect can be generated, releasing the lightning voltage through short and repeated arcing, and making the accumulated current unable to increase rapidly, but fluctuating. Therefore, the voltage and parallel current borne by both ends of the insulator are always within the tolerance range, so that the insulator does not overheat. The insulator has a better protection effect.

[0043] This device has better protection against insulator damage such as surface discharge, and can achieve dynamic protection against insulator insulation failure by adjusting the length and hanging position of the shed, and adjust the insulation coordination by adjusting the gap of the liquid arc extinguishing structure in the middle of the lightning protection arc extinguishing device to ensure the protection of the insulator. It also prevents the upper cross arm from polluting the insulator surface.

[0044] In this embodiment, if Figure 2 As shown, the upper sealed arc extinguishing unit A and the lower sealed arc extinguishing unit B are both configured as a sealed tube, and the upper electrode 1 and the lower electrode 6 are respectively provided at both ends of the sealed tube for sealing, and insulating oil 2 is provided in the sealed tube, and the side of the sealed tube is provided with a skirt 4. The sealed tube also includes a ceramic tube 3 and a protective shell 5, the protective shell 5 is provided on the outside of the ceramic tube 3, and the skirt 4 is provided on the outside of the protective shell 5.

[0045] The ceramic shell filled with insulating liquid medium is made of inorganic non-metallic materials with high hardness, high temperature resistance and high pressure resistance. The semi-enclosed space inside the ceramic tube is filled with liquid and is the area of ​​arc elastic collision. The upper and lower ends of the cylindrical ceramic tube are sealed with conductive electrodes. The electrode is fixed between the external hardware and the internal discharge structure with bolts near the cross arm. The distance between the upper and lower electrodes and the hanging position are adjusted according to the actual line conditions to ensure protection against surface discharge.

[0046] When lightning strikes a ceramic tube filled with liquid, a liquid-electric effect is generated, forming a strong shock wave at the beginning of arc construction, which acts on the discharge channel in the form of impulse or impact pressure to cut off the arc. The peak value of the impact pressure and the peak value of the arc are almost coincident in time, which can form the best arc extinguishing effect. In addition, due to the effect of the Coulomb force in the tube, the movement of external electrons is affected, forcing the arc to enter the tube. The arc entering the tube cannot maintain electrical neutrality because it is smaller than the size of the Debye shield. It is repelled from the new lightning protection arc extinguishing device by the strong force of the external electric field. At the same time, when lightning strikes the metal electrode, a certain pressure is applied to the 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 its 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 directed to the center of the ceramic tube, thereby cutting off the arc at the initial stage of arc construction, reducing the amplitude of the current through intermittent discharge, reducing the steepness of the lightning wave, and prolonging the discharge time of the arc.

[0047] The upper electrode 1 includes an upper graphite electrode, an intermediate metal electrode and a lower graphite electrode. The intermediate metal electrode is fixed at one end of the ceramic tube 3 and the protective shell 5, the upper graphite electrode is arranged on the upper layer of the intermediate metal electrode, and the lower graphite electrode is arranged at the bottom of the intermediate metal electrode and arranged in the ceramic tube 3. The lower electrode 6 includes an upper graphite electrode and a bottom metal electrode. The bottom metal electrode is fixed at the other end of the ceramic tube 3 and the protective shell 5, and the upper graphite electrode is arranged in the ceramic tube 3 and connected to the bottom metal electrode.

[0048] The insulating tube filled with insulating oil is made of high-hardness, high-temperature and high-pressure resistant inorganic non-metallic material and is cylindrical; the insulating tube is tightly connected to the composite insulation to fix the insulating tube and the umbrella skirt; the closed space inside the insulating tube is filled with insulating oil and is the area of ​​arc elastic collision.

[0049] When lightning strikes a pole tower or transmission line, the fully sealed liquid arrester discharges before the insulator string, and the lightning arc is poured into the insulating tube inside the arrester, generating a liquid-electric effect, forming a powerful shock wave, which acts on the discharge channel in the form of impulse or impact pressure to cut off the arc. At the same time, when the arc enters the insulating tube, it applies a certain pressure to the liquid in the insulating 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 generate a greater force on the inner wall of the insulating tube. This force rebounds after acting on the outer shell, forming a force pointing to the center of the insulating tube, thereby achieving the purpose of cutting off the arc.

[0050] Embodiment 2:

[0051] This embodiment is different from embodiment 1 in that Figure 3 As shown, the upper sealed arc extinguishing unit A and the lower sealed arc extinguishing unit B are both set as a sealed tube, and the upper electrode 1 and the lower electrode 6 are respectively set at both ends of the sealed tube for sealing. Insulating oil 2 is set in the sealed tube, and the side of the sealed tube is provided with a skirt 4. The inner side of the sealed tube is provided with an arc extinguishing grid 9 at intervals, and the horizontal length of the arc extinguishing grid 9 is greater than half of the inner diameter of the sealed tube. An upper tip electrode 8 is set at the bottom of the upper electrode 1, and a lower tip electrode 11 is set at the upper end of the lower electrode 6. The upper tip electrode 8 and the lower tip electrode 11 are relatively vertically arranged, and the upper tip electrode 8 and the lower tip electrode 11 are both graphite electrodes.

[0052] In this embodiment, the arc extinguishing grid 9 is made of insulating material, and the arc extinguishing grid 9 is arranged as a semicircular structure. The arc extinguishing grids 9 arranged on the inner walls of the two semicircles in the sealed tube are arranged alternately, and convex piers 10 are arranged between the arc extinguishing grids 9 on the same semicircle, and the convex piers 10 on the inner wall of one semicircle are arranged opposite to the arc extinguishing grid 9 on the inner wall of the other semicircle.

[0053] The hydroelectric effect and Pascal effect increase the pressure and temperature inside the ceramic tube, generating a force directed from the ceramic tube wall toward the center. Under this force, the arc moves toward the tip of the arc extinguishing grid, which lengthens the arc. Under the blowing of the insulating oil on the arc, the arc temperature decreases, causing the arc to extinguish more quickly. The longer the arc formed in the ceramic tube, the greater the force on the ceramic tube wall, and conversely the greater the impact force to cut off the arc, thus completing the arc extinguishing.

[0054] The specific working process of the arc extinguishing device is:

[0055] Step 1: When lightning strikes a tower or transmission line, the fully sealed liquid lightning arrester discharges before the insulator string, and the lightning arc is injected into the insulating tube inside the lightning arrester.

[0056] Step 2: When an arc discharge is triggered in a sealed tube filled with insulating oil, the liquid-electric effect generates a shock wave that rushes to the side. When an arc discharge is triggered in a ceramic tube filled with insulating oil, part of the insulating oil 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 cannot be compressed itself, when liquid phase discharge is performed in the discharge channel, the mechanical effect of power is exhibited to the outside world, and a force that impacts the ceramic tube wall is formed in the ceramic tube. Due to the mutuality of force, the ceramic tube wall generates a shock wave in the insulating oil medium;

[0057] Step 3: Pascal effect enhances the liquid-electric effect. When the arc acts on the insulating oil 2, a part of the static insulating oil 2 undergoes a pressure change, which is transmitted to all directions inside the sealed tube without changing in magnitude. When the impact arc acts on the metal electrode, it applies pressure to the insulating oil in the ceramic tube. According to Pascal's principle, a part of the static fluid in the closed container undergoes a pressure change, which is transmitted to all directions without changing in magnitude. Starting from the discharge channel in the ceramic tube, it impacts the surrounding insulating oil medium with a greater force, which rebounds after hitting the ceramic tube wall.

[0058] Step 4: As the arc extinguishing grid 9 is arranged in the sealed tube, the length of the arc in the sealed tube becomes longer, and the convex pier 10 is arranged at the same time to increase the surface area of ​​the sealed tube. The shock waves of the liquid-electric effect and the Pascal effect impact the side and then return to impact, concentrating on the impact and extinguishing of the arc channel, generating an intermittent discharge mode, and the breakdown volt-second characteristic becomes gentle, thereby reducing the breakdown starting voltage and the residual voltage value.

[0059] The hydroelectric effect and Pascal effect increase the pressure and temperature inside the ceramic tube, generating a force directed from the ceramic tube wall to the center. Under this force, the arc moves toward the tip of the arc extinguishing grid, and the tip lengthens the arc. Under the blowing of the insulating oil on the arc, the arc temperature decreases, causing the arc to extinguish more quickly. The longer the arc formed in the ceramic tube, the greater the force on the ceramic tube wall, and conversely the greater the impact force to cut off the arc. The force rebounds after acting on the outer shell, forming a force directed to the center of the insulating tube. The dielectric generates a polarization current in the impact pre-breakdown stage, which reduces the breakdown voltage and the breakdown voltage value corresponding to a short period of time, making the dielectric's corresponding breakdown volt-second characteristic become gentle. The frequent arc extinguishing and frequent reignition mechanisms suppress the arc intensity and prolong the arc duration, causing the discharge intensity and steepness to be greatly attenuated at the same time, thereby reducing the intensity of the destructive energy release.

[0060] Embodiment 3:

[0061] This embodiment is different from Embodiments 1 and 2 in that a recoil arc extinguishing unit is provided at the bottom of the upper sealed arc extinguishing unit A and the upper end of the lower sealed arc extinguishing unit B. The recoil arc extinguishing unit includes a lightning contact electrode, a recoil tube body, a recoil tube skirt, and a bottom lightning contact electrode, wherein the lightning contact electrode is arranged at the top of the recoil tube body, the recoil tube skirt is arranged at the side of the recoil tube body, the recoil tube body is arranged inside with a recoil hole, and the bottom lightning contact electrode is arranged at the lower end of the recoil hole, and the lightning contact electrode and the bottom lightning contact electrode are both graphite electrodes. When the arc is formed, recoil blow is performed simultaneously to achieve a better arc extinguishing effect.

[0062] By setting up graphite electrodes at the lightning connection point, the service life can be effectively improved. Graphite electrodes have good conductivity and are easy to introduce arcs into the recoil tube: graphite is a non-metallic material, and the conductivity of graphite is 100 times higher than that of general non-metallic minerals. Each carbon atom in graphite is connected to three other carbon atoms around it, arranged in multiple honeycomb hexagons. Since each carbon atom releases an electron, those electrons can move freely, so graphite is a conductor. Generally speaking, the discharge machining speed of graphite electrodes is 1.5 to 2 times faster than that of copper electrodes as a whole. When lightning strikes the transmission line, the graphite electrode can play the role of arc initiation, allowing the arc to enter the arc extinguishing tube smoothly.

[0063] Graphite electrodes have a very high melting point, can withstand greater currents, and are not easily deformed: Graphite electrodes have the characteristics of being able to withstand high current conditions. The softening point of copper is around 1000 degrees, and it is easy to deform due to heat; while the sublimation temperature of graphite is around 3650 degrees. The lightning strike temperature generated by a lightning current with an intensity between 5000 amperes and 50,000 amperes is as high as 3000 degrees. Therefore, metal electrodes are very easy to deform under the action of high lightning currents, produce metal powder, splash, damage the structure of the arc extinguishing chamber, and affect the effect of recoil arc extinguishing. The use of graphite electrodes can effectively solve the above problems.

[0064] Graphite electrodes have low losses: Graphite electrodes have the characteristic of being able to withstand large current conditions. Under the action of lightning arcs, a polarity effect is produced, and some eroded materials and carbon particles will adhere to the surface of the electrode to form a protective layer, ensuring that the graphite electrode has extremely small losses during the recoil arc extinguishing process, or even "zero loss".

[0065] The sealed arc extinguishing unit is provided with a high-pressure sealing structure and an external reinforcement structure, such as Figure 5 shown.

[0066] 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.

[0067] 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.

[0068] 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.

[0069] 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 on the top of the high-pressure sealing device, and the bottom cover plate 34 is arranged on the top of the high-pressure sealing device.

[0070] The top 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.

[0071] 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. An insulator retrofit arc extinguishing device for coping with insulation coordination failure, comprising an insulator string (C), an upper cross arm (D) and a lower cross arm (E), wherein the insulator string (C) is arranged between the upper cross arm (D) and the lower cross arm (E), and characterized in that: An upper sealed arc extinguishing unit (A) is arranged at the bottom of the upper cross arm (D), and a lower sealed arc extinguishing unit (B) is arranged at the upper end of the lower cross arm (E). The upper sealed arc extinguishing unit (A) and the lower sealed arc extinguishing unit (B) are arranged opposite to each other, and the upper sealed arc extinguishing unit (A) and the lower sealed arc extinguishing unit (B) are arranged on the side of the insulator string (C) and are not in contact with the insulator string (C). The upper sealed arc extinguishing unit (A) and the lower sealed arc extinguishing unit (B) are both arranged as a sealed tube, an upper electrode (1) and a lower electrode (6) are respectively arranged at both ends of the sealed tube for sealing, insulating oil (2) is arranged in the sealed tube, a skirt (4) is arranged on the side of the sealed tube, and arc extinguishing grids (9) are arranged at intervals on the inner side of the sealed tube, and the transverse length of the arc extinguishing grid (9) is greater than half of the inner diameter of the sealed tube; An upper tip electrode (8) is arranged at the bottom of the upper electrode (1), and a lower tip electrode (11) is arranged at the upper end of the lower electrode (6). The upper tip electrode (8) and the lower tip electrode (11) are relatively vertically arranged, and both the upper tip electrode (8) and the lower tip electrode (11) are graphite electrodes. The arc extinguishing grid (9) is made of insulating material, and the arc extinguishing grid (9) is arranged in a semicircular structure. The arc extinguishing grids (9) arranged on the inner side walls of the two semicircles in the sealed tube are arranged alternately, and a convex pier (10) is arranged between the arc extinguishing grids (9) on the same semicircle, and the convex pier (10) on the inner side wall of one semicircle is arranged opposite to the arc extinguishing grid (9) on the inner side wall of the other semicircle; The specific working process of the arc extinguishing device is: Step 1: When lightning strikes a tower or transmission line, the fully sealed liquid arrester discharges before the insulator string, and the lightning arc is injected into the insulating tube inside the arrester; Step 2: When an arc discharge is initiated in a sealed tube filled with insulating oil, the liquid-electric effect generates a shock wave that rushes to the side; Step 3: The Pascal effect enhances the liquid-electric effect. When the arc acts on the insulating oil (2), when a certain part of the static insulating oil (2) undergoes a pressure change, the pressure will be transmitted to all directions inside the sealed tube without changing in magnitude. Step 4: Since an arc extinguishing grid (9) is provided in the sealed tube, the length of the arc in the sealed tube becomes longer, and at the same time, a convex pier (10) is provided to increase the surface area of ​​the sealed tube. The shock waves of the liquid-electric effect and the Pascal effect impact the side and then return to impact, and concentrate on impacting and extinguishing the arc channel, thereby generating an intermittent discharge mode, and the breakdown volt-second characteristic becomes gentle, thereby reducing the breakdown starting voltage and the residual voltage value.

2. The arc extinguishing device for insulator reconstruction to cope with insulation coordination failure according to claim 1, characterized in that: A recoil arc extinguishing unit is arranged at the bottom of the upper sealed arc extinguishing unit (A) and the upper end of the lower sealed arc extinguishing unit (B), and the recoil arc extinguishing unit includes a lightning contact electrode, a recoil tube body, a recoil tube skirt, and a bottom lightning contact electrode. The lightning contact electrode is arranged at the top of the recoil tube body, the recoil tube skirt is arranged at the side of the recoil tube body, the inside of the recoil tube body is arranged as a recoil hole, and the lower end of the recoil hole is arranged with a bottom lightning contact electrode, and the lightning contact electrode and the bottom lightning contact electrode are both graphite electrodes.

3. The arc extinguishing device for insulator reconstruction to cope with insulation coordination failure according to claim 1, characterized in that: The upper sealed arc extinguishing unit (A) and the lower sealed arc extinguishing unit (B) are both arranged as a sealed tube, an upper electrode (1) and a lower electrode (6) are respectively arranged at both ends of the sealed tube for sealing, insulating oil (2) is arranged in the sealed tube, a skirt (4) is arranged on the side of the sealed tube, and the sealed tube also includes a ceramic tube (3) and a protective shell (5), the protective shell (5) is arranged on the outside of the ceramic tube (3), and the skirt (4) is arranged on the outside of the protective shell (5).

4. The arc extinguishing device for insulator reconstruction to cope with insulation coordination failure according to claim 3, characterized in that: The upper electrode (1) comprises an upper graphite electrode, an intermediate metal electrode and a lower graphite electrode, the intermediate metal electrode is fixed to one end of the ceramic tube (3) and the protective shell (5), the upper graphite electrode is arranged on the upper layer of the intermediate metal electrode, the lower graphite electrode is arranged at the bottom of the intermediate metal electrode and is arranged in the ceramic tube (3), and the lower electrode (6) comprises an upper graphite electrode and a bottom metal electrode, the bottom metal electrode is fixed to the other end of the ceramic tube (3) and the protective shell (5), and the upper graphite electrode is arranged in the ceramic tube (3) and is connected to the bottom metal electrode.

5. The arc extinguishing device for insulator reconstruction to cope with insulation coordination failure according to claim 1, characterized in that: The specific process of step 2 is: an arc discharge is triggered in a ceramic tube filled with insulating oil, and part of the insulating oil in the discharge channel is instantly vaporized, decomposed, and ionized into high-temperature plasma and 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 cannot be compressed by itself, when liquid phase discharge is performed in the discharge channel, the mechanical effect of power is shown to the outside world, and a force that impacts the ceramic tube wall is formed in the ceramic tube. Due to the mutuality of force, the ceramic tube wall generates a shock wave in the insulating oil medium; The specific process of step 3 is as follows: when the impact arc acts on the metal electrode, it applies pressure to the insulating oil in the ceramic tube. According to Pascal's principle, a part of the static fluid in the closed container undergoes a pressure change, which is transmitted in all directions without changing in magnitude. Starting from the discharge channel in the ceramic tube, it impacts the surrounding insulating oil medium with a greater force, and the force rebounds after hitting the ceramic tube wall.

6. The arc extinguishing device for insulator reconstruction to cope with insulation coordination failure according to claim 5, characterized in that: The specific process of step 4 is that the hydraulic effect and the Pascal effect increase the pressure and temperature in the ceramic tube, generating a force directed from the ceramic tube wall to the center. Under this force, the arc moves toward the tip of the arc extinguishing grid, and the tip lengthens the length of the arc. Under the blowing of the insulating oil on the arc, the arc temperature decreases, so that the arc is extinguished more quickly. The longer the arc formed in the ceramic tube, the greater the force on the ceramic tube wall. Conversely, the greater the impact force to cut off the arc. The force rebounds after acting on the outer shell, forming a force directed to the center of the insulating tube. The medium generates a polarization current in the impact pre-breakdown stage, which reduces the breakdown voltage and reduces the breakdown voltage value corresponding to a short period of time, so that the medium's corresponding breakdown volt-second characteristic becomes gentle, and the frequent arc extinguishing and frequent reignition mechanisms suppress the arc intensity and prolong the arc duration, so that the discharge intensity and steepness are greatly attenuated at the same time, thereby reducing the intensity of destructive energy release.

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