A lightning protection device for transmission lines

Abstract

The present invention discloses a lightning protection device for a transmission line, which includes a multi-chamber arc extinguishing structure and a compressed gas arc extinguishing structure respectively connected to the insulator string of the protected circuit. Among them, the multi-chamber arc extinguishing structure includes an insulating outer wall and a plurality of spherical electrodes fixed inside the insulating outer wall. The plurality of spherical electrodes are arranged side by side, and a semi-closed arc extinguishing chamber is formed between two adjacent spherical electrodes and the insulating outer wall. The semi-closed arc extinguishing chamber has a jet outlet. The grounding electrode in the spherical electrode is connected to the grounding end of the insulator string of the protected circuit. The compressed gas arc extinguishing structure includes a signal acquisition and trigger device and a compressed gas storage device both connected to the high-voltage end of the insulator string of the protected circuit. The compressed gas storage device stores arc extinguishing gas. The primary arc extinguishing process is realized through the multi-chamber arc extinguishing structure, and the secondary arc extinguishing process is realized by gas blowing arc extinguishing through the compressed gas arc extinguishing structure, which can quickly and reliably extinguish the power frequency follow-up arc caused by lightning strike short-circuit faults.

Description

Technical Field

[0001] The present invention relates to the technical field of overvoltage protection devices for transmission lines, and particularly to a lightning protection device for transmission lines. Background Art

[0002] Statistical data shows that lightning is the main cause of tripping accidents in transmission and distribution lines, accounting for 70%-80% of the total number of tripping times. Therefore, the frequent occurrence of lightning-induced tripping accidents seriously threatens the safe and stable operation of the power grid. In most cities at home and abroad, the overhead bare conductors of the distribution network are transformed into insulated conductors through line transformation to improve the safety level of their operation. However, at the same time, it has also caused a relatively serious problem of lightning-induced breakage of insulated conductors. Research shows that the main reason for lightning-induced breakage is that after the lightning strikes and breaks through the insulator string, a power-frequency follow current arc is formed on the lightning flashover channel, and the arc burns continuously at a fixed point, resulting in the breakage of the wire. Therefore, studying lightning protection measures with fast and reliable arc extinguishing capabilities can fundamentally solve the problem of lightning-induced breakage of insulated conductors, which has an important role in improving the reliability of the operation of transmission and distribution lines.

[0003] The parallel gap is a "diversion" type lightning protection device, which has the advantages of simple structure, convenient installation, low price, and can protect the insulator from arc burning. It has been widely used in the lightning protection of transmission and distribution lines, and a guide for the use of parallel gaps for insulators in AC overhead transmission lines has been formulated. However, after the air gap of the parallel gap is broken down, the power-frequency follow current arc cannot be actively extinguished, and the continuous burning of the arc will cause phase-to-phase short circuit or even three-phase short circuit, resulting in an increase in the lightning tripping rate and a serious accident of wire fusing. Summary of the Invention

[0004] In order to solve the above technical problems, the present invention provides a lightning protection device for transmission lines, which can reduce the lightning tripping rate and reduce serious accidents of wire fusing.

[0005] The present invention provides a lightning protection device for a transmission line, which includes a multi-chamber arc extinguishing structure and a compressed gas arc extinguishing structure respectively connected to the insulator string of the protected circuit. Among them, the multi-chamber arc extinguishing structure includes an insulating outer wall and a plurality of spherical electrodes fixed inside the insulating outer wall. The plurality of spherical electrodes are arranged side by side, and a semi-closed arc extinguishing chamber is formed between two adjacent spherical electrodes and the insulating outer wall. The semi-closed arc extinguishing chamber has a spray outlet. The grounding electrode in the spherical electrode is connected to the grounding end of the insulator string of the protected circuit. The compressed gas arc extinguishing structure includes a signal acquisition and trigger device and a compressed gas storage device both connected to the high-voltage end of the insulator string of the protected circuit. The compressed gas storage device stores arc extinguishing gas. The signal acquisition and trigger device is used to detect the current duration of the arc formed after the lightning protection device is broken down. If the lightning overvoltage is higher than the breakdown voltage of the lightning protection device, the arc is confined in each semi-closed arc extinguishing chamber to achieve segmented arc extinguishing. When the signal acquisition and trigger device detects that the current duration of the arc is higher than the set arc extinguishing time, the compressed gas storage device releases the arc extinguishing gas to the arc.

[0006] Optionally, the insulating outer wall includes a housing and a plurality of partition plates fixed inside the housing. One side of the housing is open. The plurality of partition plates are arranged in parallel inside the housing and extend towards the open side of the housing. The plurality of spherical electrodes are fixedly arranged on the partition plates one by one. A semi-closed arc extinguishing chamber is formed between two adjacent spherical electrodes and the housing and the partition plates. A plurality of spray outlets are formed between the open side of the housing and the plurality of partition plates.

[0007] Optionally, the distance between two adjacent spherical electrodes is 2 mm - 8 mm.

[0008] Optionally, the diameter of the spherical electrode is 8 mm - 12 mm.

[0009] Optionally, the spherical electrode includes a high-voltage spherical electrode, an intermediate spherical electrode, and a grounding spherical electrode. The grounding spherical electrode is connected to the grounding end of the insulator string.

[0010] Optionally, a high-voltage adjustable electrode is further connected to the high-voltage end of the insulator string of the protected circuit. There is a gap between the high-voltage adjustable electrode and the high-voltage spherical electrode. The high-voltage adjustable electrode is connected with a grading ring.

[0011] Optionally, the compressed gas storage device includes an air chamber that stores arc extinguishing gas. The discharge port of the air chamber faces the gap between the high-voltage adjustable electrode and the high-voltage spherical electrode, and a switching valve is arranged on the discharge port.

[0012] Optionally, the grounding end of the insulator string is connected to the grounding electrode of the multi-chamber arc extinguishing structure through a grounding electrode, and the high-voltage end of the insulator string is connected to the compressed gas storage device and the high-voltage adjustable electrode through a high-voltage fixed electrode.

[0013] Optionally, an adjustment structure is connected between the high-voltage fixed electrode and the high-voltage adjustable electrode to drive the high-voltage adjustable electrode away from or close to the multi-chamber arc extinguishing structure.

[0014] Optionally, the adjustment structure includes a spring, and the spring is connected between the high-voltage fixed electrode and the high-voltage adjustable electrode.

[0015] The technical solution provided by the embodiment of the present invention has the following advantages compared with the prior art:

[0016] The lightning protection device for transmission lines provided by the embodiment of the present invention, based on the designed principle, the breakdown voltage of the lightning protection device is lower than that of the insulator string. When the lightning overvoltage propagates to the high-voltage end of the insulator string through the transmission line, if the lightning overvoltage is lower than the breakdown voltage of the lightning protection device, the protection device does not operate. If the lightning overvoltage is higher than the breakdown voltage of the lightning protection device, the lightning protection device is broken down prior to the insulator string. At this time, the arc is confined in the semi-closed arc extinguishing chamber of the multi-chamber arc extinguishing structure. At this time, the high-energy arc causes the pressure in the semi-closed arc extinguishing chamber of the multi-chamber arc extinguishing structure to rise sharply. The pressure difference between the inside and outside of the semi-closed arc extinguishing chamber causes a high-speed air flow to be generated in the chamber, driving the arc to be ejected from the spray outlet into the cold air outside the chamber. The arc is stretched, the arc temperature drops sharply, and the deionization effect is enhanced, resulting in the extinction of the arc. If the signal acquisition trigger device detects that the duration of the arc current is lower than the set arc extinguishing time, the arc extinguishing is successful, which is the primary arc extinguishing process of the lightning protection device for transmission lines. If the signal acquisition trigger device detects that the duration of the arc current is higher than the set arc extinguishing time, it is considered that the primary arc extinguishing process of the multi-chamber arc extinguishing structure fails to extinguish the arc. At this time, the compressed gas storage device is triggered to release the arc extinguishing gas, and the high-speed air flow acts on the arc, driving the arc to be stretched sharply. At the same time, the deionization effect is enhanced and the arc tends to extinguish. The signal acquisition trigger device detects the duration of the arc current again. If the current duration is lower than the set arc extinguishing time, the arc extinguishing is successful. If the current duration is higher than the set arc extinguishing time, the arc extinguishing fails, and the compressed gas storage device is triggered again to release the arc extinguishing gas for gas-blowing arc extinguishing until the arc extinguishes when the current duration is lower than the set arc extinguishing time. This is the secondary arc extinguishing process of the lightning protection device for transmission lines. The primary arc extinguishing process is realized through the multi-chamber arc extinguishing structure, and the secondary arc extinguishing process is realized through the gas-blowing arc extinguishing of the compressed gas arc extinguishing structure, which can quickly and reliably extinguish the power frequency follow current arc caused by the lightning strike short-circuit fault, solve the problems of power frequency follow current and lightning trip caused by the transmission line being struck by lightning, and can effectively improve the safety and reliability of the operation of the transmission line. Description of the Drawings

[0017] Figure 1 It is a schematic structural diagram of a lightning protection device for transmission lines provided by an embodiment of the present invention;

[0018] Figure 2Schematic diagram of the multi-chamber arc extinguishing structure provided by the embodiment of the present invention;

[0019] Figure 3 Flow chart of the operation of a lightning protection device for a transmission line provided by the embodiment of the present invention.

[0020] Explanation of reference numerals:

[0021] 1. Insulator string; 2. High-voltage fixed electrode; 3. High-voltage adjustable electrode; 4. Spring; 5. Grounding electrode; 6. Multi-chamber arc extinguishing structure; 7. Signal acquisition and triggering device; 8. Compressed gas storage device; 9. High-voltage spherical electrode; 10. Grounding spherical electrode; 11. Intermediate spherical electrode; 12. Semi-closed arc extinguishing chamber; 13. Arc; 14. Insulating outer wall; 140. Outer shell; 141. Partition; 142. Spray outlet. Specific embodiments

[0022] The following combines the drawings to describe in detail a specific embodiment of the present invention, but it should be understood that the protection scope of the present invention is not limited by the specific embodiment.

[0023] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "axial", "radial", "circumferential", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the technical solutions of the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention.

[0024] The present invention will be described below through several specific embodiments. In order to keep the description clear and concise in the following embodiments of the present invention, the detailed description of known functions and known components may be omitted. When any component of the embodiment of the present invention appears in more than one drawing, the component may be represented by the same reference numeral in each drawing.

[0025] Refer to Figure 1 、 Figure 2 and Figure 3 , Figure 1 Schematic diagram of a lightning protection device for a transmission line provided by the embodiment of the present invention, Figure 2 Schematic diagram of the multi-chamber arc extinguishing structure provided by the embodiment of the present invention, Figure 3 Flow chart of the operation of a lightning protection device for a transmission line provided by the embodiment of the present invention, as shown in Figure 1 、 Figure 2 and Figure 3As shown in the figure, an embodiment of the present invention provides a lightning protection device for a transmission line, which includes a multi-chamber arc extinguishing structure 6 and a compressed gas arc extinguishing structure respectively connected to the insulator string 1 of the protected circuit. Among them, the multi-chamber arc extinguishing structure 6 includes an insulating outer wall 14 and a plurality of spherical electrodes fixed inside the insulating outer wall 14. The plurality of spherical electrodes are arranged side by side, and a semi-closed arc extinguishing chamber 12 is formed between two adjacent spherical electrodes and the insulating outer wall 14. The semi-closed arc extinguishing chamber 12 has a spray outlet 142. The grounding electrode in the spherical electrode is connected to the grounding end of the insulator string 1 of the protected circuit. It should be noted that the multi-chamber arc extinguishing structure 6 is composed of a plurality of semi-closed arc extinguishing chambers 12 connected in series, and the primary arc extinguishing process is realized by segmental arc extinguishing in the semi-closed arc extinguishing chamber 12. The compressed gas arc extinguishing structure includes a signal acquisition and trigger device 7 and a compressed gas storage device 8 both connected to the high-voltage end of the insulator string 1 of the protected circuit. The compressed gas storage device 8 stores arc extinguishing gas. The signal acquisition and trigger device 7 is used to detect the current duration of the arc 13 formed after the lightning protection device is broken down. It should be understood that the signal acquisition and trigger device 7 is used to collect lightning strike signals and current duration, and then trigger the action of the compressed gas storage device 8 through logical judgment of the signals. When the primary arc extinguishing process is difficult to meet the arc extinguishing ability, the compressed gas arc extinguishing structure is started to realize the secondary arc extinguishing process. If the lightning overvoltage is higher than the breakdown voltage of the lightning protection device, the arc 13 is constrained in each semi-closed arc extinguishing chamber 12 to realize segmental arc extinguishing. When the signal acquisition and trigger device 7 detects that the current duration of the arc 13 is higher than the set arc extinguishing time, the compressed gas storage device 8 releases arc extinguishing gas to the arc 13.

[0026] The lightning protection device for transmission lines provided by the embodiments of the present invention, based on the designed principle, has a breakdown voltage lower than that of the insulator string 1. When the lightning overvoltage propagates to the high-voltage end of the insulator string 1 through the transmission line, if the lightning overvoltage is lower than the breakdown voltage of the protection device, the protection device does not operate. If the lightning overvoltage is higher than the breakdown voltage of the protection device, the lightning protection device is broken down prior to the insulator string 1. At this time, the arc 13 is confined within the semi-closed arc extinguishing chamber 12 of the multi-chamber arc extinguishing structure 6. At this time, the high-energy arc 13 causes the pressure in the semi-closed arc extinguishing chamber 12 of the multi-chamber arc extinguishing structure 6 to rise sharply. The pressure difference between the inside and outside of the semi-closed arc extinguishing chamber 12 causes a high-speed air flow to be generated inside the chamber, driving the arc 13 to be ejected from the ejection port 142 into the cold air outside the chamber. The arc 13 is stretched, the temperature of the arc 13 drops sharply, and the deionization effect is enhanced, resulting in the extinction of the arc 13. Since the air insulation medium in the semi-closed arc extinguishing chamber 12 gradually recovers after the arc 13 is extinguished, the self-healing property of the multi-chamber arc extinguishing structure 6 is realized, and thus the arc extinguishing can be repeated multiple times. If the signal acquisition trigger device 7 detects that the duration of the arc 13 current is lower than the set arc extinguishing time, the arc extinguishing is successful, which is the primary arc extinguishing process of the lightning protection device for transmission lines. If the signal acquisition trigger device 7 detects that the duration of the arc 13 current is higher than the set arc extinguishing time, it is considered that the primary arc extinguishing process of the multi-chamber arc extinguishing structure 6 fails to extinguish the arc. At this time, the compressed gas storage device 8 is triggered to release the arc extinguishing gas, and the high-speed air flow acts on the arc 13, driving the arc 13 to be stretched sharply. At the same time, the deionization effect is enhanced, and the arc 13 tends to be extinguished. The signal acquisition trigger device 7 detects the duration of the arc 13 current again. If the current duration is lower than the set arc extinguishing time, the arc extinguishing is successful. If the current duration is higher than the set arc extinguishing time, the arc extinguishing fails, and the compressed gas storage device 8 is triggered again to release the arc extinguishing gas for gas-blowing arc extinguishing until the arc 13 is extinguished when the current duration is lower than the set arc extinguishing time. This is the secondary arc extinguishing process of the lightning protection device for transmission lines. The primary arc extinguishing process is achieved through the multi-chamber arc extinguishing structure 6, and the secondary arc extinguishing process is achieved through the gas-blowing arc extinguishing of the compressed gas arc extinguishing structure. It can quickly and reliably extinguish the power-frequency follow current arc caused by the lightning strike short-circuit fault, solve the problems of power-frequency follow current and lightning trip caused by the transmission line being struck by lightning, and can effectively improve the safety and reliability of the operation of the transmission line.

[0027] Refer again to Figure 2, the insulating outer wall 14 includes a housing 140 and a plurality of partition plates 141 fixed within the housing 140. One side of the housing 140 is open. The plurality of partition plates 141 are arranged in parallel within the housing 140 and extend towards the open side of the housing 140. A plurality of spherical electrodes are fixedly mounted on the partition plates 141 one by one. A semi-closed arc extinguishing chamber 12 is formed between two adjacent spherical electrodes and the housing 140 and the partition plates 141. A plurality of ejection ports 142 are formed between the open side of the housing 140 and the plurality of partition plates 141. Here, the ejection port 142 can be set as a straight cylindrical outlet, and the shape of the chamber is not limited herein. Both the housing 140 and the plurality of partition plates 141 fixed within the housing 140 are made of silicone rubber insulating material.

[0028] Specifically, the distance between two adjacent spherical electrodes is 2 mm - 8 mm. This small distance is to form a high pressure in a very small space for the arc 13, so that the arc 13 is ejected from the ejection port 142 of the semi-closed arc extinguishing chamber 12. The number of semi-closed arc extinguishing chambers 12 is different under different voltage levels and also needs to be set based on different arc extinguishing requirements. Here, an initial range of 50 - 100 can be given. The arc extinguishing ability of this number of semi-closed arc extinguishing chambers 12 is used in combination with compressed gas arc extinguishing.

[0029] The diameter of the spherical electrode is set considering the insulation strength of the multi-chamber arc extinguishing structure 6. In the embodiment of the present invention, the diameter of the spherical electrode is 8 mm - 12 mm.

[0030] Specifically, the spherical electrode includes a high-voltage spherical electrode 9, an intermediate spherical electrode 11, and a grounded spherical electrode 10. The grounded spherical electrode 10 is connected to the grounding end of the insulator string 1, so that the multi-chamber arc extinguishing structure 6 has a certain insulation strength.

[0031] In the embodiment of the present invention, a high-voltage adjustable electrode 3 is further connected to the high-voltage end of the insulator string 1 for protecting the circuit. There is a gap between the high-voltage adjustable electrode 3 and the high-voltage spherical electrode 9. The high-voltage adjustable electrode 3 is connected with a grading ring. The gap between the high-voltage adjustable electrode 3 and the high-voltage spherical electrode 9 has a certain insulation strength, meeting the insulation coordination with the insulator string 1. The impulse voltage generator is used to measure the volt-second characteristic curve of the lightning protection device in the embodiment of the present invention, ensuring that the volt-second characteristic curve of the lightning protection device in the embodiment of the present invention is below the volt-second characteristic curve of the insulator string 1. If the lightning overvoltage is higher than the breakdown voltage of the lightning protection device, the lightning protection device is broken down prior to the insulator string 1. At this time, the arc 13 is constrained within the semi-closed arc extinguishing chamber 12 of the multi-chamber arc extinguishing structure 6. This is the first step for the lightning protection device provided by the embodiment of the present invention to achieve the protection action.

[0032] Specifically, the compressed gas storage device 8 includes a gas chamber in which arc extinguishing gas is stored. The discharge port of the gas chamber faces the gap between the high-voltage adjustable electrode 3 and the high-voltage spherical electrode 9. A switching valve is provided at the discharge port. The gap between the high-voltage adjustable electrode 3 and the high-voltage spherical electrode 9 of the multi-chamber arc extinguishing structure 6 can be adjusted to meet the insulation coordination characteristics of different transmission line insulator strings 1 and the lightning protection device of the present invention.

[0033] Optionally, the grounding end of the insulator string 1 and the grounding electrode of the multi-chamber arc extinguishing structure 6 are connected through a grounding electrode 5, and the high-voltage end of the insulator string 1 is connected to the compressed gas storage device 8 and the high-voltage adjustable electrode 3 through a high-voltage fixed electrode 2. Firstly, the multi-chamber arc extinguishing structure 6 has a certain insulation strength. Secondly, there is an air gap between the high-voltage spherical electrode 9 and the high-voltage adjustable electrode 3, which has a certain insulation strength.

[0034] Optionally, an adjusting structure is connected between the high-voltage fixed electrode 2 and the high-voltage adjustable electrode 3 to drive the high-voltage adjustable electrode 3 away from or close to the multi-chamber arc extinguishing structure 6. The adjusting structure can change the length of the air gap between the high-voltage spherical electrode 9 and the high-voltage adjustable electrode 3, so that the insulation strength of the whole device can be adjusted to meet the insulation coordination with the insulator.

[0035] Optionally, the adjusting structure includes a spring 4. The spring 4 is connected between the high-voltage fixed electrode 2 and the high-voltage adjustable electrode 3. The spring 4 can change the length of the air gap, so that the insulation strength of the whole device can be adjusted to meet the insulation coordination with the insulator.

[0036] If the lightning overvoltage is higher than the breakdown voltage of the lightning protection device, the lightning protection device is broken down prior to the insulator string 1. At this time, the arc 13 is constrained between the high-voltage fixed electrode 2 and the high-voltage spherical electrode 9, and within the semi-closed arc extinguishing chamber 12 of the multi-chamber arc extinguishing structure 6. This is the first step for the lightning protection device of the present invention to achieve the protection action.

[0037] After the multi-chamber arc extinguishing structure 6 is broken down, the long-gap arc 13 is divided into multiple short-gap arcs 13 by the multiple intermediate spherical electrodes 11 of the multi-chamber arc extinguishing structure 6. The arc 13 constrained within the semi-closed arc extinguishing chamber 12 causes the pressure inside the chamber to increase. The pressure difference drives the arc 13 to spray out of the chamber. The arc 13 is stretched, and the high-temperature arc 13 exchanges heat with the cold air outside the chamber, resulting in a sharp drop in the temperature of the arc 13, and the arc 13 tends to extinguish. This is the primary arc extinguishing process of the lightning protection device of the present invention. After the arc 13 extinguishes, the air insulation medium inside the chamber gradually recovers, realizing the self-healing property of the multi-chamber arc extinguishing structure 6, so that the arc extinguishing can be repeated multiple times.

[0038] The signal acquisition and triggering device 7 in the lightning protection device of the present invention is used to detect the duration of the arc 13 current. When the detected duration of the arc 13 current is higher than the set arc extinguishing time, it should be noted that the arc extinguishing time is set based on the arc extinguishing requirements of the transmission line. Then, it is considered that the primary arc extinguishing of the multi-chamber arc extinguishing structure 6 fails. At this time, the signal acquisition and triggering device 7 triggers the compressed gas storage device 8 to release the arc extinguishing gas. The high-speed airflow acts on the arc 13 between the high-voltage adjustable electrode 3 and the high-voltage spherical electrode 9, driving the arc 13 to be rapidly stretched. At the same time, the deionization effect is enhanced, and the arc 13 tends to extinguish. The signal acquisition and triggering device 7 detects the duration of the arc 13 current again. If the current duration is lower than the set arc extinguishing time, the arc extinguishing is successful. If the current duration is higher than the set arc extinguishing time, the arc extinguishing fails. The signal acquisition and triggering device 7 triggers the compressed gas storage device 8 to release the arc extinguishing gas for gas-blowing arc extinguishing again until the current duration is lower than the set arc extinguishing time and the arc 13 extinguishes. This is the secondary arc extinguishing process of the transmission line lightning protection device.

[0039] In the embodiment of the present invention, the number of chambers of the multi-chamber arc extinguishing structure 6 and the arc extinguishing time of the signal acquisition and triggering device 7 can both be artificially set to meet the requirements of different transmission lines for arc extinguishing performance and arc extinguishing reliability. The distance between the high-voltage adjustable electrode 3 and the high-voltage spherical electrode 9 can be adjusted to meet the insulation coordination characteristics of the insulator string 1 of different transmission lines and the lightning protection device of the present invention. Therefore, the present invention is a general-purpose voltage-sharing self-healing lightning protection device and can be applicable to the lightning protection requirements of different transmission lines.

[0040] The adjustable protection gap device mainly includes a high-voltage fixed electrode 2 with adjustable gap, a high-voltage adjustable electrode 3, a grounding electrode 5, and a voltage-sharing ring structure. The air gaps between the high-voltage fixed electrode 2 and the high-voltage adjustable electrode 3, and between the grounding electrode 5 and the multi-chamber arc extinguishing structure 6 can be adjusted to achieve the insulation coordination between the protection gap and the insulator string 1. The voltage-sharing ring is used to improve the voltage-sharing characteristics of the lightning protection device.

[0041] The above are only several specific embodiments of the present invention. However, the embodiments of the present invention are not limited thereto, and any changes that can be thought of by those skilled in the art should fall within the protection scope of the present invention.

Claims

1. A lightning protection device for a transmission line, characterized in that, Comprising: Multi-chamber arc extinguishing structure (6): including an insulating outer wall (14) and a plurality of spherical electrodes fixed within the insulating outer wall (14), the plurality of spherical electrodes being arranged side by side, a semi-closed arc extinguishing chamber (12) being formed between two adjacent spherical electrodes and the insulating outer wall (14), the semi-closed arc extinguishing chamber (12) having an ejection port (142), and the grounding electrode among the spherical electrodes being connected to the grounding end of the insulator string (1) of the protected circuit; Compressed gas arc extinguishing structure: including a signal acquisition and trigger device (7) and a compressed gas storage device (8) both connected to the high-voltage end of the insulator string (1) of the protected circuit, the compressed gas storage device (8) storing an arc extinguishing gas, and the signal acquisition and trigger device (7) being used to detect the current duration of the arc (13) formed after the lightning protection device is broken down; The insulating outer wall (14) includes a housing (140) and a plurality of partition plates (141) fixed within the housing (140), one side of the housing (140) being open, the plurality of partition plates (141) being arranged in parallel within the housing (140), the partition plates (141) extending towards the open side of the housing (140), and the plurality of spherical electrodes being fixedly arranged on the partition plates (141) one by one, the semi-closed arc extinguishing chamber (12) being formed between two adjacent spherical electrodes and the housing (140) and the partition plates (141), and a plurality of ejection ports (142) being formed between the open side of the housing (140) and the plurality of partition plates (141); The spherical electrodes include a high-voltage spherical electrode (9), an intermediate spherical electrode (11), and a grounding spherical electrode (10), and the grounding spherical electrode (10) is connected to the grounding end of the insulator string (1); The high-voltage end of the insulator string (1) of the protected circuit is further connected to a high-voltage adjustable electrode (3), a gap exists between the high-voltage adjustable electrode (3) and the high-voltage spherical electrode (9), and the high-voltage adjustable electrode (3) is connected to a grading ring; The compressed gas storage device (8) includes a gas chamber storing an arc extinguishing gas, the discharge port of the gas chamber facing the gap between the high-voltage adjustable electrode (3) and the high-voltage spherical electrode (9), and a switching valve being arranged on the discharge port; The grounding end of the insulator string (1) is connected to the grounding electrode of the multi-chamber arc extinguishing structure (6) through a grounding electrode (5), and the high-voltage end of the insulator string (1) is connected to the compressed gas storage device (8) and the high-voltage adjustable electrode (3) through a high-voltage fixed electrode (2); An adjusting structure is connected between the high-voltage fixed electrode (2) and the high-voltage adjustable electrode (3) to drive the high-voltage adjustable electrode (3) to move away from or close to the multi-chamber arc extinguishing structure (6); The adjusting structure includes a spring (4), and the spring (4) is connected between the high-voltage fixed electrode (2) and the high-voltage adjustable electrode (3); If the signal acquisition trigger device (7) detects that the duration of the arc current is lower than the set arc extinguishing time, the arc extinguishing is successful. This is the primary arc extinguishing process of the transmission line lightning protection device. If the signal acquisition trigger device (7) detects that the duration of the arc current is higher than the set arc extinguishing time, it is considered that the primary arc extinguishing process of the multi-chamber arc extinguishing structure (6) fails. At this time, the compressed gas storage device (8) is triggered to release the arc extinguishing gas. The high-speed gas flow acts on the arc, driving the arc to be rapidly stretched. At the same time, the deionization effect is enhanced and the arc tends to extinguish. The signal acquisition trigger device (7) detects the duration of the arc current again. If the current duration is lower than the set arc extinguishing time, the arc extinguishing is successful. If the current duration is higher than the set arc extinguishing time, the arc extinguishing fails, and the compressed gas storage device (8) is triggered again to release the arc extinguishing gas for gas-blowing arc extinguishing until the arc extinguishes when the current duration is lower than the set arc extinguishing time. This is the secondary arc extinguishing process of the transmission line lightning protection device.

2. The lightning protection device for a transmission line according to claim 1, characterized in that The distance between two adjacent spherical electrodes is 2 mm - 8 mm.

3. The lightning protection device for a transmission line according to claim 1, characterized in that, The diameter of the spherical electrode is 8 mm - 12 mm.

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