A voltage-limiting arc-extinguishing lightning protection device and a lightning current discharge method

Abstract

This invention relates to the field of lightning protection device technology, specifically to a voltage-limiting arc-extinguishing lightning protection device and a lightning current discharge method. The device includes a gas-blowing arc-extinguishing mechanism and a surge arrester body. The gas-blowing arc-extinguishing mechanism includes a housing, a gas-generating component, and an end cap at the top of the housing. The housing has a connected gas-generating chamber and a discharge chamber. The end cap has a first electrode located in the discharge chamber. The gas-generating component is located inside the gas-generating chamber and is used to release arc-blowing gas upon heating during a lightning strike. The surge arrester body has a second electrode and connecting fittings at both ends of its resistive core. The second electrode corresponds to the discharge chamber and is used to flashover with the first electrode. One end of the discharge chamber is connected to the outside, and the arc-blowing gas flows out from one end of the discharge chamber to carry away the arc within the discharge chamber. During a lightning strike, the first and second electrodes flashover, causing the gas-generating component to release arc-blowing gas upon heating. The arc-blowing gas flows out from one end of the discharge chamber to carry away the arc, preventing reignition. Its combination with the surge arrester body can cut off the power frequency follow current and smoothly limit voltage.

Description

Technical Field

[0001] This invention relates to the field of lightning protection device technology, specifically to a voltage-limiting arc-extinguishing lightning protection device and a lightning current discharge method. Background Technology

[0002] Lightning, an unpredictable and high-energy natural phenomenon, generates instantaneous overvoltages and lightning currents in the tens of kA range, making it the most frequent and significant external source of damage to power systems, threatening their safe and stable operation. When lightning strikes a line or facility, the core hazard lies not only in the initial impulse insulation flashover but also in the subsequent establishment of a continuous power frequency follow current arc. If this arc cannot be interrupted in a timely and reliable manner, the protective circuit breaker will fail to reclose successfully, resulting in a continuous power outage and interruption of power supply.

[0003] Mainstream lightning protection devices mainly include gap-type surge arresters and nonlinear resistor-type voltage-limiting surge arresters. Gap-type surge arresters discharge lightning current through air gap breakdown. Their arc-extinguishing capability depends on the arc crossing zero and the natural recovery of the air medium. The air heats up and expands, blowing out of the discharge cavity to extinguish the arc. However, the arc is prone to reignition, leading to line tripping or device burnout. Voltage-limiting surge arresters utilize the nonlinear characteristics of zinc oxide resistors to achieve smooth voltage limiting, but they themselves do not have the ability to interrupt power frequency follow current. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the aforementioned background technology and provide a voltage-limiting arc-extinguishing lightning protection device and a lightning current discharge method.

[0005] The technical solution adopted in this invention is: a voltage-limiting arc-extinguishing lightning protection device, which includes, The gas-blowing arc-extinguishing mechanism includes a housing, a gas-generating component, and an end cap located at the top of the housing. The housing has a gas-generating chamber and a discharge chamber that are connected to each other. The end cap has a first electrode located in the discharge chamber. The gas-generating component is located in the gas-generating chamber and is used to release arc-blowing gas when heated during a lightning strike. The surge arrester body has a second electrode and a connecting fitting at both ends of the resistor core of the surge arrester body. The second electrode corresponds to the discharge cavity and is used to flash over with the first electrode. One end of the discharge cavity is connected to the outside, and the arc-blowing gas is used to flow out from one end of the discharge cavity and carry away the electric arc inside the discharge cavity.

[0006] Furthermore, the discharge chamber is connected to the outside at one end near the second electrode and has a gas passage between the other end and the gas generation chamber; the shell includes an outer cylinder and an inner cylinder, and the gas generation chamber is formed between the outer cylinder and the inner cylinder. The bottom of the gas generation chamber is closed and a sealing plate is provided at the top. The sealing plate is provided with a gas port for connecting the gas passage. The inner cavity of the inner cylinder serves as the discharge chamber; a pressure accumulation valve assembly for increasing the gas pressure of the arc blowing gas is provided in the gas passage.

[0007] Furthermore, the sealing plate is located on the bottom side of the end cap.

[0008] Furthermore, the air passage is located on the end cap, and the pressure valve assembly includes an elastic element and a valve plate located at one end of the elastic element. The valve plate closes the air passage under the action of the elastic element, and is pushed to compress the elastic element and slide open the air passage after the arc-blowing gas is pressurized.

[0009] Furthermore, one end of the elastic element is connected to the inner wall of the air passage, and the other end is connected to the valve plate. The valve plate blocks the air port under the force of the elastic element.

[0010] Furthermore, the airway includes an arc-shaped air guide surface, with one end of the airway connected to an air inlet and the outlet of the other end facing the second electrode.

[0011] Furthermore, the end cap is fixed to the supporting crossbeam; multiple umbrella skirts are axially spaced on the outer cylinder.

[0012] Furthermore, the air passage is an annular structure surrounding the first electrode, and the air inlet and valve plate are annular structures adapted to the air inlet end of the air passage. Multiple elastic elements are circumferentially spaced and connected to the valve plate. The gas generating material of the gas generating component includes polytetrafluoroethylene, and the gas generating component has multiple venting holes inside.

[0013] Furthermore, the gas-generating component includes expanded polytetrafluoroethylene (ePTFE) with a built-in mesh structure.

[0014] Furthermore, the surge arrester body also includes a protective cylinder, and the resistor core gap is disposed inside the protective cylinder.

[0015] Furthermore, the gap between the protective cylinder and the resistor core is filled with nitrogen gas.

[0016] Furthermore, the resistor core includes an insulating cylinder, multiple resistor units connected in series inside the insulating cylinder, and a second electrode connected to the resistor unit located at the top.

[0017] Furthermore, multiple support rings are axially spaced outside the resistor core, with the inner and outer sides of the support rings abutting against the resistor core and the protective cylinder, respectively; through holes are provided on the support rings to connect the upper and lower sides of the support rings; and connecting hardware is used to fix the bottom end of the protective cylinder to the resistor unit located at the bottom end.

[0018] Furthermore, the resistive unit includes a zinc oxide resistor.

[0019] Furthermore, the gas-blown arc-extinguishing mechanism is spaced apart from the arrester body, allowing the bottom of the discharge cavity to communicate with the outside. The second electrode is inserted into the discharge cavity and has a gap between it and the inner wall of the discharge cavity. The top of the umbrella skirt is provided with a sealing plate, and the top of the second electrode protrudes through the sealing plate and is located inside the discharge cavity.

[0020] Furthermore, the gas-blowing arc-extinguishing mechanism is fixedly connected to the opposite side of the surge arrester body via a connecting sleeve, and the connecting sleeve is provided with an exhaust channel that connects the discharge chamber to the outside.

[0021] Furthermore, the umbrella skirt sleeve is provided with multiple umbrella skirts at intervals along the outer axis. The umbrella skirts include large umbrellas and small umbrellas with an outer diameter smaller than that of the large umbrellas. The large umbrellas and small umbrellas are alternately arranged at intervals along the axial direction of the umbrella skirt sleeve.

[0022] In another aspect, the present invention provides a method for discharging lightning current, using the voltage-limiting arc-extinguishing lightning protection device provided by the present invention, the method comprising, When lightning strikes the first electrode, the first electrode flashes over with the second electrode. The gas-generating chamber is heated by flashover, causing the gas-generating component to decompose and release the arc-blowing gas. The pressure of the arc-blowing gas in the gas-generating chamber is increased by the pressure-accumulating valve assembly, so that the arc-blowing gas is injected into the discharge chamber. The arc is carried away by blowing out the arc-blowing gas from one end of the discharge cavity; The overvoltage on the second electrode is discharged through the resistive core of the surge arrester body.

[0023] According to the present invention, a lightning current discharge method is provided. The method for heating and decomposing the gas-generating component to release the arc-blowing gas includes... Polytetrafluoroethylene is used as the gas generating component, and the negative gas generated by thermal decomposition and discharge when heated is used as the arc blowing gas. The arc-blowing gas is guided from the gas generation chamber into the discharge chamber through a curved gas guide surface. The method of increasing the gas pressure of the arc-blowing gas in the gas-generating chamber through the pressure-accumulating valve assembly, so that the arc-blowing gas is injected into the discharge chamber, includes the following steps: The valve plate is connected by an elastic element. The force of the elastic element causes the valve plate to block the air passage, increasing the gas pressure of the arc-blowing gas in the gas generation chamber. The pressurized arc-blowing gas pushes the valve plate to compress the elastic element and move to open the air passage, forming a jet that is injected into the discharge chamber.

[0024] The beneficial effects of this invention include: 1. During a lightning strike, the first electrode of the air-blowing arc-extinguishing mechanism flashes over with the second electrode on the arrester body through the discharge chamber; this causes the discharge chamber and the gas-generating chamber to heat up, and the gas-generating component releases arc-blowing gas. The arc-blowing gas enters the discharge chamber and is blown out from one end of the discharge chamber, carrying away the arc in the discharge chamber and cutting off the power frequency follow current. Based on the automatic blowing out of the air in the discharge chamber, the arc is blown out by the arc-blowing gas, which can improve the arc-extinguishing effect and effectively prevent reignition. Through the resistor core of the arrester body, the resistance drops sharply during lightning overvoltage, which can quickly conduct the lightning energy into the ground and achieve rapid current discharge. Through the combination of gap discharge and the nonlinear characteristics of the resistor core, the power frequency follow current is cut off while the voltage is smoothly limited, protecting the lightning protection device and line equipment. 2. The gap between the outer cylinder and the inner cylinder serves as a gas-generating chamber for placing the gas-generating component. The two ends of the gas passage connect the gas-generating chamber and the discharge chamber. When the gas-generating component releases arc-blowing gas upon heating, the gas pressure of the arc-blowing gas in the gas-generating chamber is increased by the pressure accumulation valve assembly and then injected into the gas passage to increase the kinetic energy of the arc-blowing gas. The gas is then ejected from the other end of the discharge chamber, carrying away the electric arc in the discharge chamber and preventing the electric arc from reigniting. 3. The pressure valve assembly has a clever structure. The elastic element pushes the valve plate to block the gas passage. The gas generation element in the gas generation chamber releases more arc-blowing gas, which increases the gas pressure. This increases the force of the elastic element on the valve plate, pushing the valve plate to move and thus opening the gas passage. Compared with the arc-blowing gas directly connecting to the discharge chamber, this can increase the gas pressure of the arc-blowing gas and form a jet that is ejected from the nozzle of the gas passage, thus improving the arc extinguishing effect. 4. The air passage, with its curved air guide surface, can guide the gas from the gas generation chamber into the discharge chamber, reducing the damping of the arc-blowing gas in the air passage. Compared with the right-angle bend of the air passage, it can reduce kinetic energy loss and increase the flow rate. 5. The gas passage and valve plate are annular structures, with multiple elastic elements spaced around the circumference to connect the valve plate, facilitating the entry of the arc-blowing gas into the gas passage; polytetrafluoroethylene is used as the gas-generating material of the gas-generating component, which undergoes a thermal decomposition reaction when heated to decompose a large amount of hydrogen-containing arc-blowing gas, which helps to quickly increase the pressure of the arc-blowing gas to form a jet and improve the arc-extinguishing effect; the guide vents inside the gas-generating component facilitate the overflow of the arc-blowing gas released by internal heating, improving the gas generation efficiency; 6. The gap between the resistor cores of the surge arrester body is located inside the protective cylinder to facilitate the thermal expansion and contraction of the resistor cores. 7. The insulating cylinder abuts against the inner wall of the protective cylinder through multiple spaced support rings, providing radial support; the support rings connect the multiple annular chambers formed between the insulating cylinder and the protective cylinder through the channel holes on the support rings; 8. Multiple resistor units are connected in series inside the insulating cylinder to form a resistor core, which realizes the functions of current leakage and smooth voltage limiting; 9. The air-blowing arc extinguishing mechanism is spaced apart from the arrester body to allow the discharge cavity to communicate with the outside world. Inserting the second electrode into the discharge cavity can improve the protection effect and reduce the adhesion of dirt. 10. The lightning current discharge method provided by this invention fully utilizes the structural characteristics of the voltage-limiting arc-extinguishing lightning protection device provided by this invention. When lightning strikes, the first and second electrodes of the air-blowing arc-extinguishing mechanism flash over, causing the internal temperature of the shell to rise. The gas-generating component decomposes under heat to produce arc-blowing gas, which enters the discharge chamber through the air passage and is blown out from one end of the discharge chamber to carry away the arc, preventing the arc from reigniting and cutting off the power frequency follow current. Through the nonlinear characteristics of the resistive core of the arrester body, the resistance value drops sharply under lightning overvoltage, dissipating the lightning energy transmitted by the second electrode, achieving smooth voltage limiting while protecting the lightning protection device.

[0025] The voltage-limiting arc-extinguishing lightning protection device of the present invention causes a flashover between the first electrode and the second electrode when the lightning overvoltage is transmitted to the first electrode, and the gas generating element is heated and releases arc-blowing gas. The arc-blowing gas is ejected from one end of the discharge cavity to the outside and carries away the arc, preventing the arc from reigniting. The overvoltage transmitted by the second electrode is transmitted to the ground through the lightning arrester body to achieve current discharge. This combination can cut off the power frequency follow current and smooth the voltage limit, and has great promotional value. Attached Figure Description

[0026] Figure 1 Schematic diagram of a voltage-limiting arc-extinguishing lightning protection device; Figure 2 Schematic diagram of the air-blown arc extinguishing mechanism; Figure 3 : Schematic diagram of the main structure of the surge arrester; Figure 4 : A schematic diagram of the structure of the connecting hardware connected to the resistor core; Wherein: 1-Shell; 11-Outer cylinder; 12-Inner cylinder; 14-Discharge chamber; 2-Gas generating component; 3-End cap; 31-First electrode; 32-Gas passage; 321-Gas guiding surface; 33-Sealing plate; 4-Surge arrester body; 41-Second electrode; 42-Resistor core; 421-Insulating cylinder; 422-Resistor unit; 423-Metal pad; 43-Connecting hardware; 44-Protective cylinder; 45-Support ring; 5-Umbrella skirt; 51-Large umbrella; 52-Small umbrella; 6-Accumulation valve assembly; 61-Elastic component; 62-Valve plate; 7-Support crossarm. Detailed Implementation

[0027] Embodiments of the present invention are described in detail below, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary, and the drawings are not drawn to scale and are intended to explain the present invention, and should not be construed as limiting the present invention.

[0028] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0029] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0030] This invention relates to a voltage-limiting arc-extinguishing lightning protection device, which combines a gap-type surge arrester with a nonlinear resistive voltage-limiting surge arrester. A gas-generating component 2 is placed inside the gas-generating chamber via the housing 1 of the gas-blowing arc-extinguishing mechanism. When a lightning overvoltage is transmitted to the first electrode 31 on the end cover 3, the first electrode 31 and the second electrode 41 on the surge arrester body 4 flashover within the discharge chamber 14. This flashover causes the discharge chamber 14 and the gas-generating chamber to heat up, and the gas-generating component 2 releases arc-blowing gas. The arc-blowing gas enters the discharge chamber 14 through the gas passage 32 and exits from the discharge chamber. One end of the arc is blown out, carrying away the electric arc in the discharge chamber 14 and cutting off the power frequency follow current. Based on the automatic blowing out of the air in the discharge chamber 14, the arc is blown out by the arc blowing gas, which can improve the arc extinguishing effect and effectively prevent reignition. Through the resistor core 42 of the surge arrester body 4, the resistance drops sharply when there is a lightning overvoltage, which can quickly conduct the lightning energy to the ground and achieve rapid current discharge. Through the combination of gap discharge and the nonlinear characteristics of the resistor core 42, the power frequency follow current is cut off while the voltage is smoothly limited, protecting the lightning protection device and line equipment.

[0031] Example 1 A voltage-limiting arc-extinguishing lightning protection device, specifically, such as Figure 1-4 As shown, the arrester includes a gas-blowing arc-extinguishing mechanism and a surge arrester body 4. The gas-blowing arc-extinguishing mechanism includes a housing 1, a gas-generating component 2, an end cap 3, and a first electrode 31. The end cap 3 is located at the top of the housing 1. The housing 1 has a gas-generating chamber and a discharge chamber 14 that are connected to each other. The first electrode 31 is located on the end cap 3 and is located inside the discharge chamber 14. The gas-generating component 2 is located inside the gas-generating chamber and is used to release arc-blowing gas when heated by lightning. The resistance of the resistor core 42 of the surge arrester body 4 has a non-linear characteristic change. When lightning strikes, the resistance drops sharply, which can quickly dissipate the lightning energy. The two ends of the resistor core 42 are respectively provided with a second electrode 41 and a connecting fitting 43. The second electrode 41 corresponds to the discharge chamber 14 and is used to flash over with the first electrode 31. One end of the discharge chamber 14 (the end close to or far from the first electrode 31) is connected to the outside. The arc-blowing gas is used to flow out from one end of the discharge chamber 14 and carry away the arc in the discharge chamber 14.

[0032] There may be no partition between the gas generating chamber and the discharge chamber 14, that is, the gas generating chamber and the discharge chamber 14 are an integral chamber. The gas generating component 2 is located in the shell 1, and the space occupied by the gas generating component 2 is the gas generating chamber. The space located next to the gas generating component 2 in the shell 1 is the discharge chamber 14. When the gas generating component 2 has a ring structure, the ring inner cavity of the gas generating component 2 is the discharge chamber 14. The arc blowing gas generated by the gas generating component 2 when heated is directly diffused into the discharge chamber 14 and ejected from one end of the discharge chamber 14 to carry away the electric arc.

[0033] In one implementation, such as Figure 1 As shown, the discharge chamber 14 is connected to the outside at one end near the second electrode 41 (bottom end of the figure), and a gas passage 32 is provided between the other end and the gas generation chamber. The arc blowing gas enters from the gas passage 32 and is discharged through the end of the discharge chamber 14 near the second electrode 41.

[0034] In one implementation, such as Figure 1-2 As shown, the housing 1 includes an outer cylinder 11 and an inner cylinder 12. The inner cylinder 12 is located inside the outer cylinder 11 with a gap. The inner cylinder 12 is an insulating thin cylinder to facilitate heat transfer to the gas generating component 2. The inner wall of the inner cylinder 12 can be coated with a protective layer to prevent the inner cylinder 12 from being burned. A gas generating chamber is formed between the inner cylinder 12 and the outer cylinder 11. The inner cavity of the inner cylinder 12 serves as a discharge chamber 14. The bottom of the gas generating chamber is closed and the top is provided with a sealing plate 33. The sealing plate 33 is provided with an air port for connecting to the gas passage 32. The gas passage 32 is provided with a pressure accumulation valve assembly 6 for the arc blowing gas pressure. The gas generating component 2 is placed in the gap between the outer cylinder 11 and the inner cylinder 12. The two ends of the gas channel 32 are connected to the gas generating chamber and the discharge chamber 14. When the gas generating component 2 releases arc-blowing gas when heated, the gas pressure of the arc-blowing gas in the gas generating chamber is increased by the pressure accumulation valve assembly 6 and then injected into the gas channel 32 to increase the carrying capacity (flow rate) of the arc-blowing gas. It is then ejected from the other end of the discharge chamber 14 to carry away the electric arc in the discharge chamber 14 and prevent the electric arc from reigniting.

[0035] Preferably, the sealing plate 33 is located at the bottom of the end cover 3, which blocks the gas generation chamber when the end cover 3 is fixed to the housing 1, and communicates with the gas passage 32 through the gas port.

[0036] Based on the air passage 32, a pressure accumulation valve assembly 6 is provided, such as Figure 2 As shown, the air passage 32 is provided on the end cap 3. The pressure valve assembly 6 includes an elastic element 61 and a valve plate 62 provided at one end of the elastic element 61. The valve plate 62 closes the air passage 32 under the force of the elastic element 61. After the arc blowing gas is pressurized, it is pushed to compress the elastic element 61 and slides to open the air passage 32 within the air passage 32.

[0037] In a specific plan, such as Figure 2As shown, one end of the elastic element 61 (spring) is connected to the inner wall of the air passage 32, and the other end is connected to the valve plate 62. The valve plate 62 blocks the air port under the force (thrust) of the elastic element 61. When the arc-blowing gas pressure is low, the valve plate 62 blocks the air passage 32 under the force of the elastic element 61. When the arc-blowing gas increases, the gas pressure increases, and the thrust of the arc-blowing gas on the valve plate 62 is greater than the force of the elastic element 61 when it blocks the valve plate 62 at the air port. This pushes the valve plate 62 to compress the elastic element 61 and move it, thereby opening the air passage 32. Compared with the arc-blowing gas directly connecting to the discharge chamber 14, this can increase the gas pressure of the arc-blowing gas, allowing the arc-blowing gas to be ejected from the outlet of the air passage 32 to form a jet, thus improving the arc-extinguishing effect.

[0038] In a specific design, the height of the gas-generating chamber is 750-900mm, and its diameter (inner diameter of the outer cylinder 11) is 150-230mm. The height of the discharge chamber 14 is approximately the same as that of the gas-generating chamber. The first electrode 31 extends into the discharge chamber 14 and can flash over with the second electrode 41 during a lightning strike. The distance between the first electrode 31 and the second electrode 41 (discharge gap) is in the range of 650-900mm. This design is suitable for high-voltage power transmission scenarios of 110KV and above. The size of the discharge gap can be adjusted according to the transmission voltage. This lightning protection device is suitable for high-voltage power transmission of 110-500KV. For example, in 110KV high-voltage power transmission, this lightning protection device with a discharge gap of 800mm is used.

[0039] In one implementation, such as Figure 2 As shown, the air passage 32 includes an arc-shaped guiding surface 321. One end of the air passage 32 is connected to the air inlet, and the outlet of the other end faces the second electrode 41. Through the arc-shaped guiding surface 321, the air passage 32 can guide gas from the gas generation chamber into the discharge chamber 14, reducing the damping of the arc-blowing gas in the air passage 32. Compared with the right-angle bend of the air passage 32, it can reduce kinetic energy loss and increase the flow rate.

[0040] In one specific design, the airway 32 has an arc-shaped curved structure, with one end connected to the gas generation chamber, and after the curve turns, it connects to the discharge chamber 14 with the outlet direction facing the second electrode 41.

[0041] In one implementation scheme, such as Figure 1 As shown, the end cap 3 is fixed to the supporting crossbeam 7; multiple umbrella skirts 5 are axially spaced on the outer cylinder 11.

[0042] In one scheme, such as Figure 2 As shown, the air passage 32 is an annular structure surrounding the first electrode 31. The side wall of the air passage 32 away from the discharge cavity 14 serves as an arc-shaped air guiding surface 321. The air port and valve plate 62 are annular structures adapted to the air inlet end of the air passage 32. Multiple elastic elements 61 are circumferentially spaced and connected to the valve plate 62.

[0043] In one implementation scheme, such as Figure 2As shown, the gas generating component 2 has multiple venting holes inside, meaning that the gas generating component 2 has a loose material structure, which is used to discharge the arc-blowing gas released inside the gas generating component 2 and improve the gas generation efficiency. The gas generating material of the gas generating component 2 can be polytetrafluoroethylene. Preferably, the gas generating component 2 includes expanded polytetrafluoroethylene (ePTFE) with a built-in mesh structure, and the mesh structure serves as the venting holes.

[0044] In one implementation scheme, such as Figure 1 and Figure 3 As shown, the surge arrester body 4 also includes a protective cylinder 44, and the resistor core 42 is located inside the protective cylinder 44. The protective cylinder 44 is made of rigid material and plays a supporting role. The resistor core 42 is located inside the protective cylinder 44 to facilitate the thermal expansion and contraction of the resistor core 42.

[0045] In one implementation scheme, such as Figure 3-4 As shown, the resistor core 42 includes an insulating cylinder 421 and multiple resistor units 422 connected in series within the insulating cylinder 421. A second electrode 41 is connected to the resistor unit 422 located at the top. A connecting fitting 43 is located at the bottom of the resistor core 42 and electrically connected to the resistor unit 422 located at the bottom. Metal pads 423 can be added between adjacent resistor units 422 to prevent thermal collapse of adjacent resistor units 422. The resistor unit 422 is preferably a zinc oxide resistor, with a resistance gradient greater than 400V / mm. The insulating cylinder 421 can be made of epoxy resin or nylon. The resistor core 42, formed by multiple resistor units 422 connected in series within the insulating cylinder 421, achieves the functions of current leakage and smooth voltage limiting.

[0046] Based on the gap of the resistor core 42 being located inside the protective cylinder 44, such as Figure 3 As shown, multiple support rings 45 are axially spaced around the resistor core 42. The inner and outer sides of the support rings 45 abut against the resistor core 42 (insulating cylinder 421) and the protective cylinder 44, respectively. Through holes are provided on the support rings 45 to connect the upper and lower sides. A connecting fitting 43 is fixed to the bottom end of the protective cylinder 44 and electrically connected to the resistor unit 422 located at the bottom end. The support rings 45 can be fixed to the resistor core 42 and slide against the inner wall of the protective cylinder 44. The support rings 45 can also be inserted into the protective cylinder 44 along with the resistor core 42. Alternatively, the support rings 45 can be fixed to the inner wall of the protective cylinder 44 and slide against the resistor core 42.

[0047] Preferably, the gap between the resistor core 42 and the protective cylinder 44 is filled with nitrogen.

[0048] In one implementation scheme, such as Figure 3-4As shown, the gas-blowing arc-extinguishing mechanism is spaced apart from the arrester body 4, allowing the bottom of the discharge cavity 14 to communicate with the outside. The housing 1 and the arrester body 4 can be coaxial or angled. The second electrode 41 is inserted into the discharge cavity 14 with a gap between it and the inner wall of the discharge cavity 14. The top of the protective cylinder 44 is equipped with a sealing plate, and the top of the second electrode 41 protrudes from the sealing plate and is located inside the discharge cavity 14. The spaced-apart arrangement of the gas-blowing arc-extinguishing mechanism and the arrester body 4 allows the discharge cavity 14 to communicate with the outside. The insertion of the second electrode 41 into the discharge cavity 14 can improve the protective effect and reduce the adhesion of dirt.

[0049] In one embodiment (not shown in the figure), the gas-blowing arc-extinguishing mechanism is fixedly connected to the opposite side of the surge arrester body 4 via a connecting sleeve, and the connecting sleeve is provided with an exhaust channel that connects the discharge chamber 14 to the outside.

[0050] like Figure 3 As shown, the protective cylinder 44 of the surge arrester body 4 is provided with multiple umbrella skirts 5 at intervals along the outer axis. The umbrella skirts 5 include a large umbrella 51 and a small umbrella 52 with an outer diameter smaller than that of the large umbrella 51. The large umbrella 51 and the small umbrella 52 are alternately arranged at intervals along the axial direction of the protective cylinder 44.

[0051] In one specific design, the outer diameter of the large umbrella 51 is 80-90mm, the outer diameter of the small umbrella 52 is 65-75mm, and the total number of large umbrellas 51 and small umbrellas 52 on the gas blowing arc extinguishing mechanism and the main body of the surge arrester is 25-30, which is applicable to high-voltage power transmission scenarios of 110KV and above.

[0052] In one implementation, such as Figure 3 As shown, multiple skirts 5 on the surge arrester body 4 are integrally formed with the sleeve to form a skirt 5 cylinder, and the skirt 5 cylinder is sleeved on the outside of the protective cylinder 44; the connecting hardware 43 is fixedly connected to the end of the protective cylinder 44 away from the second electrode 41 and electrically connected to the resistor core 42. The connecting hardware 43 includes a connecting flange, which is fixedly sleeved on the outside of the end of the skirt 5 cylinder.

[0053] In a specific solution, such as Figure 1As shown, the housing 1 includes an inner cylinder 12 and an outer cylinder 11. A gas-generating component 2 is located in the gas-generating chamber between the inner cylinder 12 and the outer cylinder 11. The gas-generating component 2 is a loosely structured material with internal guiding vents. The gas-generating material is expanded polytetrafluoroethylene (ePTFE). The gas-generating chamber is a closed structure with a gas port at the top. A metal end cap 3 is located on the top of the housing 1. A first electrode 31 is located on the metal end cap 3 corresponding to the discharge chamber 14 inside the inner cylinder 12. The end cap 3 has a gas channel 32 connecting the gas port and the discharge chamber 14. One end of the gas channel 32 connects to the gas port, and the other end connects to the discharge chamber 14. The outlet of the end faces the second electrode 41 at the top of the arrester body 4; the air passage 32 has an annular structure, including an arc-shaped curved air guide surface 321 to reduce the flow resistance of the arc-blowing gas; the end cover 3 is provided with a pressure-accumulating valve assembly 6 located in the air passage 32. The pressure-accumulating valve assembly 6 includes an elastic element 61 (e.g., a spring) connected at one end to the end cover 3 (inner wall of the air passage 32) and a valve plate 62 connected to the elastic element 61. Under normal conditions (without being struck by lightning), the valve plate 62 blocks the air outlet under the force of the elastic element 61, preventing lightning strikes. The second electrode 41 at the top of the lightning arrester body 4 corresponds to the bottom of the discharge cavity 14 and is used for flashover with the first electrode 31. The top of the resistor core 42, which has a non-linear resistance characteristic, is electrically connected to the second electrode 41, and the bottom is connected to a metal flange. The resistor core 42 includes an insulating cylinder 421 and a resistor unit 422 connected in series in the insulating cylinder 421. The resistor unit 422 includes a zinc oxide resistor. Under normal working conditions, the resistance is high and it is in an insulating state. Under lightning overvoltage conditions, the resistance drops sharply. The protective cylinder 44 is gapped and sleeved on the insulating cylinder 4. Outside 21, multiple support rings 45 are axially spaced on the outer side of the protective cylinder 44. The inner and outer sides of the support rings 45 abut against the insulating cylinder 421 and the protective cylinder 44 respectively. The support rings 45 are provided with channel holes. The gap between the protective cylinder 44 and the insulating cylinder 421 is filled with nitrogen. The end cap 3 is fixed to the support crossarm 7. The small gap between the surge arrester body 4 and the gas blowout arc extinguishing mechanism allows the discharge chamber 14 to communicate with the outside. A connecting sleeve with an exhaust channel can be used to connect the opposing sides of the surge arrester body 4 and the gas blowout arc extinguishing mechanism to improve mechanical strength.

[0054] During a lightning strike, the flashover of the first electrode 31 and the second electrode 41 causes the gas-generating component 2 to decompose under heat, releasing arc-blowing gas. The increased arc-blowing gas pressure overcomes the force of the elastic component 61, pushing the valve plate 62 to move and open the gas passage 32. The arc-blowing gas is then injected into the discharge chamber 14 along the gas passage 32, forming a jet, and exits from the bottom of the discharge chamber 14, carrying away the arc within and preventing reignition. During a lightning overvoltage, the resistance of the resistor core 42 group in the arrester body 4 drops sharply, quickly dissipating the lightning energy and preventing thermal collapse. The combination of gap discharge and the nonlinear characteristics of the resistor core 42 can cut off the power frequency follow current and smoothly limit voltage, making it highly valuable for widespread application.

[0055] Example 2 In another aspect, the present invention provides a method for discharging lightning current. Using a voltage-limiting arc-extinguishing lightning protection device provided by the present invention, the discharging method includes the following steps: S1. When lightning strikes the first electrode 31, the first electrode 31 flashes over with the second electrode 41. S2. The gas generating chamber is heated by flashover, causing the gas generating element 2 to decompose and release the arc blowing gas. This step includes using polytetrafluoroethylene (such as expanded polytetrafluoroethylene) as the gas generating element 2, and using the negative gas of thermal decomposition as the arc blowing gas when heated. The arc blowing gas is guided from the gas generating chamber into the discharge chamber 14 through the arc-shaped curved gas guiding surface 321. S3. Increase the gas pressure of the arc-blowing gas in the gas-generating chamber by using the pressure-accumulating valve assembly 6, so that the arc-blowing gas is injected into the discharge chamber 14; including using an elastic element 61 to connect the valve plate 62, and using the force of the elastic element 61 to block the gas passage 32 by the valve plate 62, so that the gas-generating element 2 continues to release the arc-blowing gas, thereby increasing the gas pressure of the arc-blowing gas in the gas-generating chamber. The pressurized arc-blowing gas pushes the valve plate 62 to compress the elastic element 61 to move and open the gas passage 32, so that the arc-blowing gas forms a jet and is injected into the discharge chamber 14. S4. The arc-blowing gas is blown out from one end of the discharge cavity 14 to carry away the electric arc in the discharge cavity 14; the arc-blowing gas enters from one end of the discharge cavity 14 and is ejected from the other end to the outside to carry away the electric arc in the discharge cavity 14. S5. The overvoltage on the second electrode 41 is discharged through the resistor core 42 of the surge arrester body 4. When the lightning overvoltage is transmitted from the second electrode 41 to the resistor core 42, the resistance of the resistor core 42 drops sharply and becomes a good conductor, which can quickly discharge the lightning energy to the ground. After the lightning energy is discharged, the resistance returns to high, so that the two ends of the resistor core 42 are in an open circuit state under normal working voltage.

[0056] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A voltage-limiting arc-extinguishing lightning protection device, characterized in that: include, The gas-blowing arc extinguishing mechanism includes a housing (1), a gas-generating component (2), and an end cap (3) located at the top of the housing (1). The housing (1) is provided with a gas-generating chamber and a discharge chamber (14) that are connected to each other. The end cap (3) is provided with a first electrode (31) located in the discharge chamber (14). The gas-generating component (2) is located in the gas-generating chamber and is used to release arc-blowing gas when heated by lightning. The surge arrester body (4) has a second electrode (41) and a connecting fitting (43) at both ends of the resistor core (42) of the surge arrester body (4). The second electrode (41) corresponds to the discharge cavity (14) and is used to flash over with the first electrode (31). One end of the discharge cavity (14) is connected to the outside, and the arc blowing gas is used to flow out from one end of the discharge cavity (14) to carry away the electric arc inside the discharge cavity (14).

2. The voltage-limiting arc-extinguishing lightning protection device as described in claim 1, characterized in that: The discharge chamber (14) is connected to the outside at one end near the second electrode (41), and a gas passage (32) is provided between the other end and the gas generation chamber; the shell (1) includes an outer cylinder (11) and an inner cylinder (12), and the gas generation chamber is formed between the outer cylinder (11) and the inner cylinder (12). The bottom end of the gas generation chamber is closed and a sealing plate (33) is provided at the top end. The sealing plate (33) is provided with an air port for connecting the gas passage (32). The inner cavity of the inner cylinder (12) serves as the discharge chamber (14); a pressure accumulation valve assembly (6) for increasing the gas pressure of the arc blowing gas is provided in the gas passage (32).

3. The voltage-limiting arc-extinguishing lightning protection device as described in claim 2, characterized in that: The air passage (32) is located on the end cap (3). The pressure valve assembly (6) includes an elastic element (61) and a valve plate (62) located at one end of the elastic element (61). The valve plate (62) closes the air passage (32) under the force of the elastic element (61). After the arc blowing gas is pressurized, it is pushed to compress the elastic element (61) and slides to open the air passage (32) within the air passage (32).

4. The voltage-limiting arc-extinguishing lightning protection device as described in claim 3, characterized in that: The air passage (32) includes an arc-shaped air guide surface (321), one end of the air passage (32) is connected to the air inlet, and the outlet of the other end faces the second electrode (41).

5. The voltage-limiting arc-extinguishing lightning protection device as described in claim 4, characterized in that: The air passage (32) is an annular structure surrounding the first electrode (31), and the air inlet and valve plate (62) are annular structures adapted to the air inlet end of the air passage (32). Multiple elastic elements (61) are circumferentially spaced and connected to the valve plate (62). The gas generating material of the gas generating element (2) includes polytetrafluoroethylene, and the gas generating element (2) has multiple venting holes inside.

6. A voltage-limiting arc-extinguishing lightning protection device as described in claims 1-5, characterized in that: The surge arrester body (4) also includes a protective cylinder (44), and the resistor core (42) is located inside the protective cylinder (44); the resistor core (42) includes an insulating cylinder (421) and multiple resistor units (422) connected in series inside the insulating cylinder (421), and the second electrode (41) is connected to the resistor unit (422) located at the top.

7. The voltage-limiting arc-extinguishing lightning protection device as described in claim 6, characterized in that: The resistor core (42) is axially spaced with multiple support rings (45), and the inner and outer sides of the support rings (45) respectively abut against the resistor core (42) and the protective cylinder (44); the support rings (45) are provided with through holes to connect the upper and lower sides of the support rings (45); the connecting hardware (43) is fixed to the bottom end of the protective cylinder (44) and electrically connected to the resistor unit (422) located at the bottom end.

8. The voltage-limiting arc-extinguishing lightning protection device as described in claim 1, characterized in that: The gas-blowing arc-extinguishing mechanism is spaced apart from the arrester body (4), so that the bottom of the discharge cavity (14) is connected to the outside. The second electrode (41) is inserted into the discharge cavity (14) and a gap is left between it and the inner wall of the discharge cavity (14). The top of the protective cylinder (44) is provided with a sealing plate, and the top of the second electrode (41) protrudes through the sealing plate.

9. A method for discharging lightning current, characterized in that: Using the voltage-limiting arc-extinguishing lightning protection device as described in any one of claims 2-8, the method includes... When lightning strikes the first electrode (31), the first electrode (31) flashes over with the second electrode (41); The gas-generating chamber is heated by flashover, causing the gas-generating component (2) to decompose and release the arc-blowing gas. The pressure of the arc-blowing gas in the gas-generating chamber is increased by the pressure-accumulating valve assembly (6), so that the arc-blowing gas is injected into the discharge chamber (14). The arc is carried away by blowing out the arc gas from one end of the discharge cavity (14); The overvoltage on the second electrode (41) is discharged through the resistive core (42) of the surge arrester body (4).

10. A lightning current discharge method as described in claim 9, characterized in that: The method for heating and decomposing the gas-generating component (2) to release the arc-blowing gas includes, Polytetrafluoroethylene is used as the gas generating component (2), and the negative gas of thermal decomposition and discharge is used as the arc blowing gas when heated; The arc-blowing gas is guided from the gas generation chamber into the discharge chamber (14) by the gas guide surface (321) with an arc-shaped bend; The method of increasing the gas pressure of the arc-blowing gas in the gas-generating chamber by using the pressure valve assembly (6) to inject the arc-blowing gas into the discharge chamber (14) includes using an elastic element (61) to connect the valve plate (62), using the force of the elastic element (61) to block the gas passage (32) by the valve plate (62), increasing the gas pressure of the arc-blowing gas in the gas-generating chamber, and using the pressurized arc-blowing gas to push the valve plate (62) to compress the elastic element (61) to move and open the gas passage (32), forming a jet that is injected into the discharge chamber (14).

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