Trapezoidal arc-extinguishing lightning protection device without air gap

Abstract

The present invention discloses a trapezoidal arc-extinguishing lightning protection device without an air gap, which is mainly composed of an arc-extinguishing body, an upper electrode, and a lower electrode. The upper and lower ends of the arc-extinguishing body are respectively installed at the two ends of an insulator string through connecting hardware to form a reliable electrical connection. The arc-extinguishing body is hollow inside, and a plurality of insulating partitions are provided along the longitudinal direction of the arc-extinguishing body to form a plurality of independent recoil-injection arc-extinguishing cavities inside the arc-extinguishing body. A recoil device is placed in each recoil-injection arc-extinguishing cavity, and the recoil devices are arranged in a spiral staircase manner inside the arc-extinguishing body. A wall electrode is provided on the insulating partition between two adjacent recoil devices. The present invention effectively prevents flashover problems of lightning protection devices, reduces the lightning tripping rate of power equipment, protects power facilities, improves power grid reliability, and is conducive to safe power production.

Description

Technical Field

[0001] The invention belongs to a lightning protection device for overhead power transmission and distribution lines, and relates to a trapezoidal arc-extinguishing lightning protection device without an air gap. Background Art

[0002] Lightning strikes can cause various forms of damage and destruction to power facilities. Thundercloud discharges can cause lightning overvoltages in power systems. Common overvoltages in overhead lines include overvoltages caused by electromagnetic induction near overhead lines and overvoltages caused by direct lightning strikes on conductors. Lightning overvoltages can damage insulators and transmission lines. Lightning-induced flashover discharges can burn and dislodge the porcelain surface or cause web-like cracks in glass insulators, significantly reducing insulation strength. Lightning strikes on transmission lines or lightning conductors can cause strand breakage or even rupture, disrupting power transmission.

[0003] Lightning protection for transmission lines has always been a key component of power sector operations, and lightning faults remain a significant factor impacting power grid safety. Lightning strikes on transmission lines cause impulse flashover, which in turn generates significant power frequency freewheeling current, damaging insulator strings and hardware, leading to line accidents. Power sectors typically install lightning arresters (SPDs) on transmission lines to provide protection.

[0004] During their ongoing research, the applicant and related inventors discovered that existing lightning arresters have the following problems: 1) The arc extinguishing capability is weak, and the arc extinguishing energy of the arc extinguishing device always exceeds the flashover arc energy; 2) The arc extinguishing sensitivity is not high, and there is a problem that the arc extinguishing device does not operate under low-temperature arc conditions; 3) The durability is poor, and most arc extinguishing devices require gas-generating materials to provide arc extinguishing conditions, which results in unnecessary consumption in extreme environments; 4) The arc extinguishing and lightning protection effect is poor due to the influence of the operating mode. Summary of the Invention

[0005] The purpose of the present invention is to address the deficiencies in the prior art and provide a trapezoidal arc-extinguishing lightning protection device without an air gap.

[0006] In order to achieve the above object, the technical solution of the present invention is as follows:

[0007] A trapezoidal arc-extinguishing lightning protection device without an air gap mainly consists of an arc-extinguishing body, an upper electrode and a lower electrode; the upper electrode is fixedly mounted on the top of the arc-extinguishing body, the lower electrode is fixedly mounted on the bottom of the arc-extinguishing body, and the upper and lower ends of the arc-extinguishing body are respectively mounted on the two ends of the insulator string through connecting hardware to form a reliable electrical connection; the lower end of the arc-extinguishing body is open and the interior is hollow, and a plurality of insulating partitions are provided along the longitudinal direction of the arc-extinguishing body to form a plurality of independent recoil-injection arc-extinguishing cavities inside the arc-extinguishing body; a recoil device is placed in each recoil-injection arc-extinguishing cavity, and the recoil devices are arranged in a spiral stepped manner inside the arc-extinguishing body; a wall electrode is provided on the insulating partition between two adjacent recoil devices, and the top of the recoil device at the bottom is connected to one side of the wall electrode, and the bottom of the recoil device at the top is connected to the other side of the wall electrode, so that the recoil devices are connected together end to end in sequence; the top of the recoil device at the upper end of the arc-extinguishing body is connected to the upper electrode, and the bottom of the recoil device at the lower end of the arc-extinguishing body is connected to the lower electrode.

[0008] The present invention further describes that the recoil device primarily consists of a recoil tube and a lightning receptor. The recoil tube is open at one end, with the lightning receptor fixedly mounted at the other, making the recoil device a semi-enclosed tube with a hollow interior, one open end, and the other closed. The lightning receptor is connected to the adjacent wall electrode (the lightning receptor at the top of the recoil tube at the uppermost end of the arc extinguishing body is connected to the upper electrode). The opening direction of the recoil device is consistent with that of the arc extinguishing body.

[0009] The present invention further describes that an arc guide ring is provided at the opening of the recoil tube; the arc guide ring is connected to the adjacent wall electrode (the arc guide ring at the bottom of the recoil tube at the lower end of the arc extinguishing body is connected to the lower electrode).

[0010] The present invention further describes that the cross section of the arc extinguishing body is a honeycomb structure.

[0011] Further explanation: the arc extinguishing and lightning protection arc extinguishing body is provided with a plurality of skirts on the outer surface. The skirts are added to the outer surface of the device structure to enhance the creepage distance and avoid arc discharge along the surface.

[0012] The present invention further states that the wall electrode is an arc-conducting electrode sheet or a compressed arc-extinguishing tube. The compressed arc-extinguishing tube is provided with an arc-conducting ball inside. The compressed arc-extinguishing tube is a ceramic tube.

[0013] The present invention further describes that the inner wall of the arc extinguisher is primarily constructed of a high-strength, high-voltage-resistant non-conductive material, such as alloy ceramics, rare earth ceramics, graphene-ceramic composites, organic ceramics, and other non-conductive materials. The insulating separator is also constructed of a high-strength, high-voltage-resistant non-conductive material, such as synthetic silicone rubber, rare earth glass, graphene glass, and other non-conductive materials. The wall electrode is constructed of a highly conductive metal or non-metal, such as copper, aluminum, tungsten, nickel, iron, or graphite.

[0014] The technical principle implemented by the present invention is:

[0015] This arc-extinguishing lightning protection device is connected in parallel next to the insulator string, with a flashover air channel in the middle. Through insulation coordination, the lightning overvoltage generated when lightning strikes the tower or lightning conductor will preferentially break down the parallel channel to protect the insulator string, and the formed arc will enter the trapezoidal arc-extinguishing lightning protection device without an air gap.

[0016] The arc is an elastically deformable plasma. After passing through the arc guide ring and entering the recoil device, it is restricted by the recoil tube wall. As it enters the recoil tube's starting point, its density, velocity, and temperature increase, leading to an increase in pressure within the tube and ultimately a compression explosion. The arc strikes the lightning arrester at the bottom of the recoil tube. There, the arc experiences a reverse elastic force, causing most of the arc to change direction 180°. The arc, which rebounds due to its greater velocity, density, and pressure, experiences a cavity effect at the entrance, causing the arc to be interrupted at the recoil tube's end. The remaining arc, acting on the wall electrode Coulomb force, enters the next recoil tube, repeating the process.

[0017] The recoil tube in this patent is a narrow tube perfusion channel, which is the only channel for the arc to enter the device. Various physical changes occur during the perfusion process.

[0018] 1. Arc plasma undergoes elastic deformation. When the arc plasma enters the recoil tube inlet, its physical shape first changes from a thick arc to an extremely thin arc, and the radial pressure turns into axial pressure. Due to the narrow tube recoil effect, the ejection speed will accelerate during arc recoil.

[0019] 2. The arc temperature rise effect is intensified. When the arc becomes thinner, the arc cross-sectional area decreases. According to the formula , the arc resistance will increase significantly. Since the lightning arc is often used as a constant current source in practical work, according to the formula It can be seen that although the impact time is only a few microseconds, the overall energy will be enhanced and the internal temperature of the recoil tube will increase.

[0020] Arc radiation, convection, and conduction are three ways of energy loss. Since the heat cannot be released in a closed pipe, that is, in an exogenous blocking environment, it blocks the arc and only generates heat but does not dissipate it. Therefore, a blocking temperature rise will occur, causing the temperature inside the pipe to continue to rise.

[0021] 3. The pressure explosion effect increases dramatically. When the temperature gradually rises, the arc accumulation increases, which further intensifies the pressure explosion effect and makes the arc spray more powerful.

[0022] When the arc enters the recoil device from the lightning receptor, the recoil tube is very thin. The thick lightning arc is deformed into a long, thin arc upon entering the recoil tube, filling the entire tube. The tube exerts a force on the arc, eventually causing a crushing effect, blocking the passage of subsequent arcs and thus interrupting the arc. A small portion of the arc, due to the Coulomb force of the arc guide ring and arc guide components, enters the next recoil tube, and the above process repeats.

[0023] Compared with multi-chamber

[0024] (1) Durability comparison. The gas-generating material added to the multi-chamber needs to be baked under high temperature conditions to produce gas. Therefore, the gas-generating material in the multi-chamber arc extinguishing device is consumed under high temperature conditions, and the durability of the multi-chamber is poor. However, the injection material used in the present invention does not have consumption factors and does not require arc extinguishing through gas production mechanism. Therefore, the durability of the present invention is better.

[0025] (2) Comparison of arc extinguishing effects. When the arc passes through each of two adjacent electrodes in the multi-chamber, a condensation pole effect is generated. That is, the arc temperature is lower under the adjacent electrodes. The low-temperature arc bakes the gas-producing material, resulting in poor gas production. The contradiction between the condensation pole effect and the arc extinguishing caused by the high-temperature baking gas production results in poor arc extinguishing effect. However, the present invention adopts a narrow tube perfusion mechanism. The arc collision generates huge arc extinguishing energy. The arc extinguishing effect is excellent by utilizing the arc's own energy and collision arc extinguishing.

[0026] (3) Comparison of arc extinguishing sensitivity. According to the above durability and arc extinguishing effect, the durability of the multi-chamber is affected by high temperature, and the gas production is affected by the electrode condensation effect, that is, the low-temperature arc baking ability is extremely low. The condensation effect and the high-temperature baking gas production form a contradiction between arc extinguishing. When a small arc passes through, the arc extinguishing effect is poor. Only when a larger arc passes through can the multi-chamber operate correctly. The large arc flow will cause the relay protection to operate, that is, there will be a tripping accident. Therefore, the arc extinguishing sensitivity of the multi-chamber is not ideal. However, regardless of whether a large arc or a small arc exists, the present invention only needs the arc to enter the present invention to produce a perfusion mechanism, and the sensitivity is higher.

[0027] (4) Comparison of operating modes. According to the above sensitivity analysis, the operation of the multi-chamber is affected by external factors such as the system operating mode and short-circuit current, and there is an arc extinguishing blind zone, which makes the multi-chamber lightning protection matching very difficult. However, the present invention is not affected by external factors such as system operating mode and short-circuit current.

[0028] The advantages of the present invention are as follows:

[0029] (1) Constrain and control the arc path, so that the arc and arc extinguishing channels are consistent, eliminating the hazards of arc drift;

[0030] (2) The recoil devices in the multiple recoil-irrigated arc extinguishing chambers act on the arc to isolate different arc segments from each other. The arc is cut off at the air terminals in each recoil assembly, making it difficult for the arc to reignite.

[0031] (3) The wall electrode inside the partition outside the arc extinguishing cavity can effectively disperse the arc energy and reduce the arc to zero;

[0032] (4) The recoil device in the recoil-irrigated arc-extinguishing chamber is not affected by temperature and electromotive force during the arc-extinguishing process;

[0033] (5) The arc is extinguished in the impact arc extinguishing section and the power frequency arcing channel is destroyed, and the relay protection device is not detected;

[0034] (6) The present invention has a wide range of applications and is not affected by conductor layout, tower type, or polarity effects.

[0035] (7) Effectively prevent flashover problems of lightning protection devices, reduce the lightning tripping rate of power equipment, protect power facilities, improve power grid reliability, and facilitate safe power production. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 Schematic diagram of the installation structure of the trapezoidal arc extinguishing lightning protection device of the present invention;

[0037] Figure 2 It is an expanded view of the internal local structure of the trapezoidal arc extinguishing lightning protection device of the present invention;

[0038] Figure 3 This is a schematic diagram of the cross-sectional structure of the trapezoidal arc-extinguishing lightning protection device of the present invention;

[0039] Figure 4 It is a structural schematic diagram of the recoil device of the present invention.

[0040] The above-mentioned symbols and their corresponding component names are as follows:

[0041] 1-arc extinguishing body, 2-upper electrode, 3-lower electrode, 4-insulating partition, 5-recoil injection arc extinguishing chamber, 6-recoil device, 7-wall electrode, 8-skirt, 61-recoil tube, 62 lightning rod, 611-arc guide ring. DETAILED DESCRIPTION

[0042] The technical solution of the present invention is further described in detail below in conjunction with preferred embodiments and the accompanying drawings.

[0043] Example 1:

[0044] like Figure 2-4As shown, a trapezoidal arc extinguishing lightning protection device without air gap is mainly composed of an arc extinguishing body 1, an upper electrode 2 and a lower electrode 3; the upper electrode 2 is fixedly mounted on the top of the arc extinguishing body 1, the lower electrode 3 is fixedly mounted on the bottom of the arc extinguishing body 1, and the upper and lower ends of the arc extinguishing body 1 are respectively mounted on the two ends of the insulator string through connecting metal fittings to form a reliable electrical connection; the lower end of the arc extinguishing body 1 is open and the interior is hollow, and a number of insulating partitions 4 are provided along the longitudinal direction of the arc extinguishing body 1 so that a number of independent recoil perfusion arc extinguishing cavities 5 are formed inside the arc extinguishing body 1. A recoil device 6 is placed in each arc extinguishing cavity 5, and the recoil devices 6 are arranged in a spiral staircase inside the arc extinguishing body 1; a wall electrode 7 is provided on the insulating partition 4 between any two adjacent recoil devices 6, and the top of the recoil device 6 at the bottom is connected to one side of the wall electrode 7, and the bottom of the recoil device 6 at the top is connected to the other side of the wall electrode 7, so that the recoil devices 6 are connected together end to end in sequence; the top of the recoil device at the upper end of the arc extinguishing body 1 is connected to the upper electrode 2, and the bottom of the recoil device at the lower end of the arc extinguishing body 1 is connected to the lower electrode 3.

[0045] The recoil device 6 is mainly composed of a recoil tube 61 and a lightning receptor 62; the recoil tube 61 is open at one end and the lightning receptor 62 is fixedly installed at the other end, so that the recoil device 6 becomes a semi-enclosed pipe with a hollow interior, an open end and a closed end; the lightning receptor 62 is connected to the adjacent wall electrode 7.

[0046] An arc guide ring 611 is provided at the opening of the recoil tube 61 ; the arc guide ring 611 is connected to the adjacent wall electrode 7 .

[0047] The cross section of the arc-extinguishing body 1 is a honeycomb structure.

[0048] The wall electrode 7 is an arc-guiding electrode sheet.

[0049] Example 2:

[0050] The difference between this embodiment and embodiment 1 is that the outer surface of the arc-extinguishing body 1 is provided with a plurality of skirts 8 .

[0051] Example 3:

[0052] The difference between this embodiment and embodiment 1 is that the wall electrode adopts a compressed arc-extinguishing tube.

[0053] Example 4:

[0054] The difference between this embodiment and embodiment 3 is that an arc guide ball is provided inside the compression arc extinguishing tube.

[0055] In practical applications, such as Figure 1As shown, the arc extinguishing and lightning protection device is connected in parallel next to the insulator string, with a flashover air channel in the middle. Through insulation coordination, the lightning overvoltage generated when lightning strikes the tower or lightning conductor preferentially breaks through the parallel channel to protect the insulator string, and the formed arc enters the trapezoidal arc extinguishing and lightning protection device without an air gap.

[0056] When lightning strikes a transmission line or line, generating an induced lightning overvoltage, the lightning protection device flashes over at the high-voltage end, and a lightning current begins to flow through the high-voltage electrode. The arc can be drawn by the high-voltage electrode into the recoil perfusion arc extinguishing cavity 5 of the device. After entering the recoil device 6, due to the restriction of the recoil tube wall, the arc enters the beginning of the recoil tube 61, where its density, velocity, and temperature increase, leading to an increase in the pressure inside the tube, ultimately producing a pressure explosion effect. The arc strikes the lightning rod 62 at the bottom of the recoil tube 61. The arc is subjected to a reverse elastic force at the bottom of the blocked recoil tube 61, causing the forward direction of most of the arc to change by 180 degrees. The arc rebounds due to its greater velocity, density, and pressure. The cavity effect acts on the external arc at the entrance, causing the arc at the end of the recoil tube 72 to be cut off. A small portion of the arc enters the next recoil tube 61 due to the Coulomb force of the wall electrode, and the above process is repeated.

[0057] When lightning strikes a pole tower or a transmission line lightning conductor, causing the lightning protection device to flash over at the low-voltage end, a lightning current begins to flow through the low-voltage electrode. The arc can be drawn by the low-voltage electrode into the recoil perfusion arc extinguishing chamber 5 of the device. Since the diameter of the recoil tube device 6 is very small, the thick lightning arc will be deformed into a slender arc when entering the recoil tube 61, filling the entire pipe. The pipe will exert a force on the arc, eventually forming a pressure explosion effect, blocking the passage of subsequent arcs and cutting off the arc. The remaining arc enters the next recoil tube 61 due to the arc guide ring 71 and the Coulomb force of the wall electrode, and the above process is repeated.

[0058] Finally, it should be noted that the above embodiments are intended only to illustrate the technical solutions of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art will appreciate that modifications may be made to the technical solutions described in the above embodiments, or that some of the technical features may be replaced with equivalents; such modifications or replacements do not deviate from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A trapezoidal arc-extinguishing lightning protection device without an air gap, mainly consisting of an arc-extinguishing body (1), an upper electrode (2) and a lower electrode (3); the upper electrode (2) is fixedly mounted on the top of the arc-extinguishing body (1), the lower electrode (3) is fixedly mounted on the bottom of the arc-extinguishing body (1), and the upper and lower ends of the arc-extinguishing body (1) are respectively mounted on the two ends of an insulator string through connecting metal fittings to form a reliable electrical connection; it is characterized in that: The arc extinguishing body (1) is open at the lower end and hollow inside, and a plurality of insulating partitions (4) are provided longitudinally along the arc extinguishing body (1) so that a plurality of independent recoil perfusion arc extinguishing cavities (5) are formed inside the arc extinguishing body (1). A recoil device (6) is placed in each recoil perfusion arc extinguishing cavity (5), and the recoil devices (6) are arranged in a spiral staircase inside the arc extinguishing body (1); a wall electrode (7) is provided on the insulating partition (4) between two adjacent recoil devices (6), and the top of the recoil device (6) at the bottom is connected to one side of the wall electrode (7), and the bottom of the recoil device (6) at the top is connected to the other side of the wall electrode (7), so that the recoil devices (6) are connected together end to end in sequence; the top of the recoil device at the upper end of the arc extinguishing body (1) is connected to the upper electrode (2), and the bottom of the recoil device at the lower end of the arc extinguishing body (1) is connected to the lower electrode (3).

2. The trapezoidal arc-extinguishing lightning protection device without air gap according to claim 1 is characterized in that: The recoil device (6) is mainly composed of a recoil tube (61) and a lightning receptor (62); the recoil tube (61) is open at one end and the lightning receptor (62) is fixedly mounted at the other end, so that the recoil device (6) becomes a semi-enclosed pipe with a hollow interior, an open end and a closed end; the lightning receptor (62) is connected to an adjacent wall electrode (7).

3. The trapezoidal arc-extinguishing lightning protection device without air gap according to claim 2, characterized in that: An arc guide ring (611) is provided at the opening of the recoil tube (61); the arc guide ring (611) is connected to the adjacent wall electrode (7).

4. The trapezoidal arc-extinguishing lightning protection device without air gap according to claim 1, characterized in that: The cross section of the arc extinguishing body (1) is a honeycomb structure.

5. The trapezoidal arc-extinguishing lightning protection device without air gap according to claim 1, characterized in that: The outer surface of the arc-extinguishing body (1) is provided with a plurality of skirts (8).

6. The trapezoidal arc-extinguishing lightning protection device without air gap according to claim 1, characterized in that: The wall electrode (7) adopts an arc-guiding electrode sheet or a compressed arc-extinguishing tube.

7. The trapezoidal arc-extinguishing lightning protection device without air gap according to claim 6, characterized in that: An arc guide ball is arranged inside the compression arc extinguishing tube.

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