A multi-needle ionization lightning arrester based on a multi-layer hetero-composite electrode and a method thereof

Abstract

This invention relates to the field of lightning protection technology, specifically to a multi-needle ionization lightning arrester and method based on a multilayer heterogeneous composite electrode. Under the background thundercloud electric field, the middle field emission layer stably generates an initial electron flow and plasma, providing sufficient charge for the excitation of the upward leader. The bottom capacitor energy storage layer collects and stores the corresponding charge through an impedance matching network. When the thundercloud electric field intensifies sharply, the impedance matching network automatically switches to a low impedance state, rapidly releasing the stored energy to the top needle tip array, thereby forming a strengthened upward leader at the needle tip. Compared with existing passive lightning arresters that rely solely on macroscopic geometric parameter optimization, this invention can significantly reduce the start-up field strength, shorten the leader excitation delay, increase the initial current of the upward leader, and effectively improve the protection radius, breaking through the performance bottleneck of existing passive ionization lightning arresters.

Description

Technical Field

[0001] This invention relates to the field of lightning protection technology, specifically to a multi-needle ionization lightning arrester and method based on multilayer heterogeneous composite electrodes. Background Technology

[0002] Traditional ESE (Early Discharge) lightning rods mostly use radioactive materials or simple multi-needle structures. The former has environmental and safety issues, while the latter has limited discharge efficiency and high starting field strength.

[0003] While existing passive optimized multi-needle devices avoid radioactivity, their performance improvements largely depend on the optimization of macroscopic geometric parameters, such as the number of needles and height. This results in shortcomings in startup reliability and leader excitation intensity under weak thundercloud electric fields. Furthermore, although traditional multi-needles can generate corona at lower field strengths, the corona current is weak and insufficient to seamlessly transition into a strong-current leader when the electric field rapidly increases, leaving a performance gap. The excitation of the upward leader depends entirely on the instantaneous spatial electric field, with a single and uncontrollable energy source. It is prone to excitation failure or slow development when the electric field fluctuates or is weak, resulting in low reliability and failing to meet practical needs. Summary of the Invention

[0004] The purpose of this invention is to provide a multi-needle ionization lightning arrester and method based on multilayer heterogeneous composite electrodes, thereby solving the technical problem of performance bottlenecks in existing passive ionization lightning arresters.

[0005] The solution of the present invention to the above-mentioned technical problems is as follows: A multi-needle ionization lightning arrester based on a multilayer heterogeneous composite electrode includes a support rod and a multilayer heterogeneous composite electrode assembly disposed at the top of the support rod. The multilayer heterogeneous composite electrode assembly includes: Top-level needle tip array; The middle field emission layer is located below the top tip array and its surface is coated with a material with a high field emission coefficient. The bottom layer is a capacitor energy storage layer filled with nonlinear dielectric material and electrically connected to the middle layer field emission layer through an impedance matching network. The top-level needle array is electrically connected to the bottom-level capacitor energy storage layer.

[0006] Further defined, the top-level needle tip array includes a central main needle and multiple peripheral auxiliary needles, the multiple peripheral auxiliary needles are arranged circumferentially around the central main needle, the elevation angle of the peripheral auxiliary needles is 25°~45°, and the needle tip curvature radius of both the central main needle and the peripheral auxiliary needles is less than 0.3mm.

[0007] Further defined, the middle field emission layer includes multiple umbrella-shaped electrodes, which are all vertically spaced on the insulating pillar. The top tip array is located at the top of the insulating pillar, and the bottom capacitor energy storage layer is sleeved at the bottom of the insulating pillar. The bottom end of the insulating pillar is connected to the top end of the support rod. The surfaces of the multiple umbrella-shaped electrodes are coated with a high field emission coefficient material coating. The diameter of the umbrella-shaped electrodes increases sequentially from top to bottom, and the spacing between two adjacent umbrella-shaped electrodes increases sequentially from top to bottom.

[0008] Further specifying, the high field emission coefficient material coating is a carbon nanotube array, a graphene film, or a semiconductor material doped with rare earth metal oxides.

[0009] Further defined, the bottom capacitor energy storage layer is located below the middle field emission layer. The bottom capacitor energy storage layer includes two metal rings, which are sequentially nested along their radial direction. The space between the two metal rings is filled with a nonlinear dielectric material, such that the two adjacent metal rings and the nonlinear dielectric material between them form a capacitor pair.

[0010] Further specifying, the bottom capacitor energy storage layer includes multiple metal rings, which are sequentially nested along their radial direction, and a nonlinear dielectric material is filled between two adjacent metal rings, so that the two adjacent metal rings and the nonlinear dielectric material filling between them form a capacitor pair.

[0011] Furthermore, the ratio of the dielectric constant of the nonlinear dielectric material under a high electric field to that under a low electric field is not less than 3.

[0012] Further defined, the middle field emission layer is sleeved on the outside of the bottom capacitor energy storage layer, the outer wall of the middle field emission layer is coated with a high field emission coefficient material coating, and the space between the inner wall of the middle field emission layer and the bottom capacitor energy storage layer is filled with a nonlinear dielectric material. The middle field emission layer, the bottom capacitor energy storage layer and the nonlinear dielectric material filling the space between them constitute a capacitor pair.

[0013] Further specifying, the impedance matching network includes an air-core inductor, a damping resistor, and a varistor, and the middle layer field emission layer is electrically connected to the bottom capacitor energy storage layer in sequence through the air-core inductor, the damping resistor, and the varistor.

[0014] Furthermore, the vertical cross-section of the support column is streamlined, and a spiral guide groove is provided on the support column.

[0015] Furthermore, it also includes a self-testing module, which is used to assess the contamination or insulation degradation status of the underlying capacitor energy storage layer by calculating the equivalent parallel resistance and equivalent capacitance of the underlying capacitor energy storage layer.

[0016] A lightning protection system for transmission lines includes a multi-needle ionization lightning arrester based on a multilayer heterogeneous composite electrode, as described above, installed on towers in lightning-prone areas.

[0017] A multi-needle ionization lightning arresting method based on a multilayer heterogeneous composite electrode, and based on the aforementioned multilayer heterogeneous composite electrode-based multi-needle ionization lightning arresting device, includes the following steps: Under the background thundercloud electric field, an initial electron flow and plasma are continuously generated through the field emission mechanism by using a middle field emission layer coated with a material with a high field emission coefficient. The initial electron flow and charge in the plasma are collected and stored in the underlying capacitor energy storage layer through an impedance matching network; When the electric field of the thundercloud is enhanced to a preset threshold, the impedance matching network automatically switches to a low impedance state, rapidly releasing the energy stored in the bottom capacitor energy storage layer to the top needle array, thereby exciting the generation of an enhanced uplink leader.

[0018] The beneficial effects of this invention are as follows: 1. Under the background thundercloud electric field, this invention utilizes the middle field emission layer to stably generate the initial electron flow and plasma, providing sufficient charge for the excitation of the upward leader; the bottom capacitor energy storage layer collects and stores the corresponding charge through an impedance matching network. When the thundercloud electric field intensifies sharply, the impedance matching network automatically switches to a low impedance state, rapidly releasing the stored energy to the top needle tip array, thereby forming an enhanced upward leader at the needle tip. Compared with existing passive lightning arresters that rely solely on macroscopic geometric parameter optimization, this invention can significantly reduce the start-up field strength, shorten the leader excitation delay, increase the initial current of the upward leader, and effectively improve the protection radius, breaking through the performance bottleneck of existing passive ionization lightning arresters.

[0019] 2. This invention optimizes the spatial distribution of the ionization region by limiting the elevation angle and radius of curvature of the central main needle and the outer peripheral secondary needles of the top-layer needle tip array, forming an umbrella-shaped plasma cloud and expanding the effective protection range; by setting up multiple umbrella-shaped electrodes and optimizing their spacing to form a non-uniform electric field gradient in the vertical direction, it promotes the stable development of ionization from bottom to top; by using materials such as carbon nanotube arrays and graphene films as high field emission coatings, stable field emission under low electric fields is achieved, ensuring reliable initiation under weak thundercloud conditions; by using a capacitor pair composed of a metal ring and a nonlinear dielectric material, the equivalent capacitance of the bottom capacitor energy storage layer increases abruptly with the enhancement of the electric field, providing sufficient energy for pulse release; by using an impedance matching network composed of an air-core inductor, a damping resistor, and a varistor, a slow charge and fast discharge function is achieved, generating a voltage pulse with a multiplied amplitude at the nanosecond to microsecond level at the top-layer needle tip, effectively triggering explosive emission.

[0020] 3. By providing a coaxial sleeve-type integrated structure, this invention significantly reduces the radial dimension and overall height of the device, making it suitable for space-constrained scenarios such as communication base stations and building rooftops; by setting streamlined support rods and spiral guide channels, wind load and vortex-induced vibration are reduced, improving mechanical life; by integrating a self-testing module, the equivalent parallel resistance and capacitance are used to assess the pollution accumulation or insulation degradation status of the underlying capacitor energy storage layer, realizing online early warning of the device's health status and significantly improving the maintainability and operational reliability of the lightning protection system. Attached Figure Description

[0021] Figure 1 This is a structural diagram of the multi-needle ionization lightning arrester based on a multilayer heterogeneous composite electrode according to the present invention. Figure 2 This is a schematic diagram of the high field emission coefficient material coating of the present invention; Figure 3 This is a schematic diagram of the impedance matching network and self-test circuit of the present invention; Figure 4 This is a flowchart illustrating the steps of the multi-needle ionization lightning interception method based on a multilayer heterogeneous composite electrode according to the present invention.

[0022] In the diagram, 10-support rod; 11-insulating column; 20-top layer needle tip array; 21-central main needle; 22-outer peripheral secondary needles; 30-impedance matching network; 31-high field emission coefficient material coating; 32-umbrella-shaped electrode; 33-aluminum alloy substrate; 40-bottom layer capacitor energy storage layer; 41-metal ring; 42-nonlinear dielectric material; 50-impedance matching network. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0024] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0025] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0026] In the description of the embodiments of the present invention, it should be noted that if terms such as "upper," "lower," "horizontal," or "inner" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of the invention is in use, they are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention. Furthermore, terms such as "first" and "second" are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0027] Example 1 refer to Figure 1 This invention provides a multi-needle ionization lightning arrester based on a multilayer heterogeneous composite electrode, comprising a support rod 10 and a multilayer heterogeneous composite electrode assembly disposed at the top of the support rod 10. The support rod 10 is installed on the crossbar of the transmission tower via a bottom flange. The support rod 10 can be made of 6061-T6 aluminum alloy, which is high-strength, lightweight, and corrosion-resistant. Its vertical cross-section is streamlined, preferably teardrop-shaped, with a length-to-diameter ratio of 4:1, reducing the wind resistance coefficient to approximately 0.7. Its surface is anodized and a spiral guide groove is machined with a lead of 0.5m to further enhance wind resistance and suppress vortex shedding. Through the design of the vertical cross-section and the opening of the spiral guide groove, wind load and noise are effectively reduced, and service life and performance are improved.

[0028] The multilayer heterogeneous composite electrode assembly includes: The top-level needle array 20 is responsible for ultimately forming a strong upward leader channel.

[0029] The middle field emission layer 30 is located below the top tip array 20. Its surface is coated with a high field emission coefficient material coating 31, which has an extremely high field enhancement factor and a low work function. It can stably generate weak electron flow and initial plasma through field emission mechanism under the low background electric field established by thunderclouds, such as 5-10kV / m.

[0030] The bottom capacitor energy storage layer 40 is filled with nonlinear dielectric material 42 and is electrically connected to the middle field emission layer 30 through impedance matching network 50. The top tip array 20 is electrically connected to the bottom capacitor energy storage layer 40.

[0031] The bottom capacitor energy storage layer 40 is used to collect and store the charge generated by the middle field emission layer 30 through the impedance matching network 50. Due to the characteristics of the nonlinear dielectric material 42, its equivalent capacitance increases sharply with the increase of the electric field, so that more energy can be stored at the critical point of the thundercloud electric field. When the thundercloud electric field is further enhanced to the point of near breakdown, the impedance matching network 50 enables the energy stored in the bottom capacitor energy storage layer 40 to be released quickly and synergistically to the top tip array 20. Thus, on the basis of the natural electric field, a strengthened pulse electric field is added to the tip of the top tip array 20, which triggers a strong field-induced explosion electron emission at the tip, thereby greatly advancing and powerfully exciting the upward leader.

[0032] Specifically, the top-level needle tip array 20 includes a central main needle 21 and multiple peripheral auxiliary needles 22. The multiple peripheral auxiliary needles 22 are arranged circumferentially around the central main needle 21. The elevation angle of the peripheral auxiliary needles 22 is 25°~45°. The needle tip curvature radius of both the central main needle 21 and the peripheral auxiliary needles 22 is less than 0.3mm. In order to control costs, the needle tip curvature radius of the central main needle 21 is not less than 0.1mm.

[0033] The central main needle 21 can be made of titanium alloy with a diameter of 8mm. After heat treatment, the radius of curvature of the needle tip is machined to 0.15mm, and the tip-enhanced electric field makes β>500. The number of peripheral auxiliary needles 22 can be 6 to 8. Taking 6 needles as an example, the 6 peripheral auxiliary needles 22 are equally spaced around the circumference of the central main needle 21. The elevation angle of the peripheral auxiliary needles 22 is determined by electrostatic field simulation. When the elevation angle is 30° to 35°, the ionization region generated by the peripheral auxiliary needles 22 can be optimally integrated with that generated by the central main needle 21, forming... The umbrella-shaped plasma cloud has the widest space charge distribution, and the elevation angle is taken as 30° for example. The tip curvature radius of the outer peripheral needle 22 is ≤0.25mm, for example 0.2mm, and the tip distribution circle diameter is 200mm, which expands the effective ionization volume and forms a cooperative discharge umbrella region. Preferably, both the central main needle 21 and the outer peripheral needle 22 can be made of tungsten copper alloy W80Cu20 by electrical discharge precision machining, which ensures its high melting point and good conductivity while improving its resistance to electrical erosion.

[0034] To further explain, the middle field emission layer 30 includes multiple umbrella-shaped electrodes 32, which are coaxially arranged and spaced apart in the vertical direction. The umbrella-shaped electrodes 32 are all sleeved on the insulating pillar 11. At this time, the top tip array 20 is located at the top of the insulating pillar 11, and the bottom capacitor energy storage layer 40 is sleeved on the bottom of the insulating pillar 11. The bottom end of the insulating pillar 11 is connected to the top end of the support rod 10. The insulating pillar 11 can be a ceramic insulating pillar. Optionally, multiple ceramic insulating sleeves are sleeved on the support rod 10 and connected to the support rod 10. The three umbrella-shaped electrodes 32 and the top tip array 20 are all connected to the support rod 10 through the ceramic insulating sleeves.

[0035] Taking three umbrella-shaped electrodes 32 as an example, the surfaces of the three umbrella-shaped electrodes 32 are coated with a high field emission coefficient material coating 31, and the diameter of the umbrella-shaped electrodes 32 increases sequentially from top to bottom. For example, the diameters of the three umbrella-shaped electrodes 32 are 200mm, 300mm and 400mm respectively. This progressively enlarging design can collect a larger range of space charges. The umbrella-shaped electrodes 32 are made of conductive material, such as an aluminum alloy substrate 33. The spacing between two adjacent umbrella-shaped electrodes 32 increases sequentially from top to bottom, and the spacing of the lower layer is 1.2 to 1.5 times that of the upper layer, forming an effective electric field gradient and promoting ionization development. For example, the spacing between two adjacent umbrella-shaped electrodes 32 is 80mm and 100mm respectively. In order to form a non-uniform electric field gradient in the vertical direction, the upper layer spacing is small, which makes the field strength concentrated and easy to start first. The lower layer spacing is large, which provides diffusion space for the plasma generated in the upper layer, and can collect a wider range of background ionization charges, promoting ionization development from bottom to top.

[0036] To further explain, the high field emission coefficient material coating 31 is a carbon nanotube array, a graphene film, or a semiconductor material doped with rare earth metal oxides.

[0037] refer to Figure 2 The high field emission coefficient material coating 31 employs an in-situ grown carbon nanotube (CNT) array on a silicon micro-tip array. First, a silicon micro-tip array with an aspect ratio >10 is fabricated on the surface of an aluminum alloy substrate 33 using microelectromechanical systems (MEMS) technology. The micro-tip height can be selected as 10 μm, and the emission point density is approximately 102. 6 / cm², with a tip curvature radius of approximately 50nm, and then oriented CNTs are grown on the tip of the microtip using CVD, with CNT lengths selectable from 1 to 2μm; combining the mechanical strength of the microtip with the ultra-high field enhancement factor of CNTs greater than 1000, a stable field emission current of approximately 100nA / cm² can be generated under an electric field of 5kV / m, and a stable field emission current of approximately 200nA / cm² can be generated under an electric field of 8kV / m.

[0038] To further explain, the bottom capacitor energy storage layer 40 is located below the middle field emission layer 30. The bottom capacitor energy storage layer 40 includes multiple metal rings 41, and the number of metal rings 41 can be selected as two. The two metal rings 41 are nested in sequence along their radial direction to form two concentric circles. The material of the metal rings 41 can be aluminum. In this case, the two metal rings 41 are the middle ring and the inner ring from the outside to the inside. The middle ring and the inner ring are filled with a nonlinear dielectric material 42, so that the inner ring, the middle ring and the nonlinear dielectric material 42 between them constitute the first capacitor pair C1. Taking the plate area of ​​the first capacitor pair as an example of 300cm², the thickness of the nonlinear dielectric material 42 is 2mm. The estimated value of the low field capacitance of the first capacitor pair is about 150pF, and the estimated value of the high field capacitance of the first capacitor pair is about 0.6nF, thereby achieving an increase of about 4 times in the capacitor jump energy storage capacity under electric field triggering.

[0039] Specifically, the ratio of the dielectric constant of the nonlinear dielectric material 42 under high electric field to that under low electric field is not less than 3 to ensure a significant capacitor jump energy storage effect; the nonlinear dielectric material 42 can be selected from Bao 0.7 Sro 0.3 TiO3 doped with 1.0 wt% MnCO3, with Mn doping improving voltage resistance and stability, yields barium strontium titanate ceramics after sintering. The dielectric constant εr is approximately 2000 under low electric fields less than 10 kV / cm. When the electric field is increased to near the lightning leader excitation critical field strength exceeding 50 kV / cm, the dielectric constant εr can nonlinearly increase to 8000~10000, thus achieving a jump-type energy storage of capacitance.

[0040] For further explanation, please refer to Figure 3 The impedance matching network 50 adopts a π-type RLC network, including an air-core inductor L1, a damping resistor R1, and a varistor MOV1. A varistor MOV1 is connected in parallel between two adjacent metal rings 41 as a fast release switch, and then connected in series with an air-core inductor L1 and a damping resistor R1 to the middle layer field emission layer 30. The air-core inductor L1 can be selected from 5 to 100 mH, so that the discharge pulse width is adjustable within 0.1–10 μs. Taking 22 mH as an example, the damping resistor R1 is used to suppress oscillation cycles and concentrate the energy release. Taking 150 Ω as an example, the operating voltage of the varistor MOV1 corresponds to a spatial electric field of 15~25 kV / m, which is lower than the common downward leader initiation field strength, ensuring early action. Taking the operating voltage of the varistor MOV1 as an example, 1.5 kV corresponds to a spatial electric field strength of 20 kV / m, and the estimated pulse amplitude gain is ≥3 times.

[0041] For further explanation, please refer to Figure 3 In order to monitor the health status of the bottom capacitor energy storage layer 40 in a timely manner, the multi-needle ionization lightning arrester based on multilayer heterogeneous composite electrodes provided in this embodiment also includes a self-test module. The self-test module is used to assess the pollution accumulation or insulation degradation status of the bottom capacitor energy storage layer 40 by calculating the equivalent parallel resistance and equivalent capacitance of the bottom capacitor energy storage layer 40.

[0042] Specifically, the self-test module adopts a low-frequency AC injection method based on a microcontroller (MCU). The MCU controls a signal source to generate a 1V@1Hz sinusoidal test voltage, which is applied between the inner and middle loops in the bottom capacitor energy storage layer 40 to avoid polarization effects in DC measurements; alarm resistor R3.

[0043] The equivalent parallel resistance Rp and capacitance Cp are calculated by measuring the current amplitude and phase in the circuit using a precision operational amplifier.

[0044] During diagnosis, the alarm resistance threshold is set in advance according to the pollution level. Taking the warning when the alarm resistance threshold is 1 GΩ to 5 GΩ and the alarm when it is ≤1 GΩ as an example; if Rp > 5 GΩ and the Cp value is stable within the nominal range, it represents that the current state is good, and a green light can be used for indication; if Rp drops to meet 1 GΩ < Rp ≤ 5 GΩ, at this time the Cp value may increase slightly due to the high dielectric constant of water, which represents that a warning needs to be given, and a yellow light can be used for indication; if Rp ≤ 1 GΩ, an alarm needs to be given, a red light can be used for indication, and the alarm signal can be reported through the reserved RS-485 interface to achieve three-level status warning, improving maintainability and system reliability.

[0045] The self-check module can adopt the method of high-voltage energy harvesting + supercapacitor energy storage, obtaining weak electric energy from the power frequency or lightning electric field induced by the device itself to achieve complete self-power supply.

[0046] Working principle: When a thundercloud approaches and the background electric field E0 slowly rises to 8 kV / m, the high-field electron emission coefficient material coating 31 starts stable field electron emission, generating a nanoampere-level electron current. At this time, the varistor MOV is in a high-resistance state. The air-core inductor L has a small impedance to slow-changing current, and part of the charge flows through the impedance matching network 50 to the bottom capacitor energy storage layer 40, allowing the charge to slowly charge from the middle layer field electron emission layer 30 to the bottom capacitor energy storage layer 40, and the time constant is about seconds.

[0047] When the electric field rapidly increases to more than 20 kV / m, the dielectric constant of the nonlinear dielectric material 42 increases sharply, and the stored energy of the capacitor pair increases. At the same time, the voltage across the capacitor pair rises rapidly to the operating voltage of the varistor MOV1 due to the increase in the electric field. If it is designed to correspond to a field strength of 20 kV / m, the varistor MOV1 instantaneously breaks down and turns into a low-resistance state. The energy stored in the capacitor pair forms an underdamped oscillation circuit through the air-core inductor L1 and the damping resistor R1, and a voltage pulse with a nanosecond-microsecond level and amplitude multiplication is coupled on the tips in the top tip array 20, causing the local electric field strength at the tip to increase by several orders of magnitude, triggering explosive emission and forming a strong upward leader.

[0048] Applicable environment: It is applicable to the poles and towers of high-voltage transmission lines. In the vulnerable strike sections of ultra-high voltage transmission lines, 2 to 4 sets of the multi-pin ionization lightning arrester based on multi-layer heterogeneous composite electrodes provided by this embodiment are installed on each pole. The total height without the support rod 10 is about 1.2 m, optimizing the electric field distribution and mechanical stability; the total mass is about 15 kg, controlling the additional load on the pole; the protection level is IP65, ensuring long-term operation in harsh outdoor environments.

[0049] Simulation effect: Preliminary results based on finite element electromagnetic field simulation and circuit-discharge joint simulation, along with simulation results from existing devices, are shown in Table 1: Table 1 Comparison of Simulation Results

[0050] As can be seen from Table 1, the multi-needle ionization lightning arrester based on multilayer heterogeneous composite electrodes provided in this embodiment can meet the actual use requirements and is superior to existing devices.

[0051] Example 2 Unlike Embodiment 1, in order to adapt to space-constrained scenarios such as communication base stations, the height of the device needs to be optimized. The multi-needle ionization lightning arrester based on multilayer heterogeneous composite electrodes provided in this embodiment has a total height controlled to no more than 0.8m and a total mass not exceeding 8kg. The middle field emission layer 30 and the bottom capacitor energy storage layer 40 are both selected as conductive sleeves. At this time, the middle field emission layer 30 is selected to be sleeved on the outside of the bottom capacitor energy storage layer 40. The outer wall of the middle field emission layer 30 is coated with a high field emission coefficient material coating 31. The space between the inner wall of the middle field emission layer 30 and the bottom capacitor energy storage layer 40 is filled with a nonlinear dielectric material 42. The middle field emission layer 30, the bottom capacitor energy storage layer 40 and the nonlinear dielectric material 42 filling the space between them form a capacitor pair.

[0052] Specifically, the outer diameter of the middle field emission layer 30 can be selected as 180mm, the outer diameter of the bottom capacitor energy storage layer 40 can be selected as 120mm, the gap between the middle field emission layer 30 and the bottom capacitor energy storage layer 40 is 3mm, that is, the width of the nonlinear dielectric material 42 is 3mm, which greatly reduces the radial dimension, maintains functional integrity, and makes the electric field more concentrated.

[0053] The number of peripheral auxiliary needles 22 can be reduced to four, the elevation angle of peripheral auxiliary needles 22 can be increased to 35°, the tip curvature radius is ≤0.25mm, and the ionization region is appropriately reduced.

[0054] The high field emission coefficient material coating 31 is printed using a screen printing process, where a composite paste of graphene nanosheets and silver paste is printed on a specific area of ​​the surface of the aluminum alloy substrate 33 to form a coating with a thickness of about 20 μm. After low-temperature sintering, a porous conductive network is formed with a threshold electric field of about 10~12 kV / m, which reduces the process cost.

[0055] For the impedance matching network 50, the air-core inductor L1, damping resistor R1 and varistor MOV1 can be integrated on the ceramic substrate to improve reliability, vibration resistance and better parameter consistency.

[0056] The self-check module can use red and green indicator lights for local reminders, omitting yellow warnings or directly indicating through the red indicator light when 1 GΩ < Rp ≤ 5 GΩ; furthermore, it can use RF wireless beacons for reporting.

[0057] Embodiment 3 Different from Embodiment 1, in key facilities such as nuclear power and chemical industries, in order to further improve the reliability of application, it is preferred that the number of the bottom-layer capacitive energy storage layers 40 is two, and any one of the bottom-layer capacitive energy storage layers 40 is used as a backup. The two bottom-layer capacitive energy storage layers 40 are respectively electrically connected to the middle-layer field emission layer 30 through corresponding impedance matching networks 50.

[0058] Specifically, referring to Figure 1 and Figure 3 , the bottom-layer capacitive energy storage layer 40 includes a plurality of metal rings 41. The plurality of metal rings 41 are sequentially sleeved along their radial directions to form a plurality of concentric circles. The material of the metal rings 41 can be selected as aluminum, and taking three metal rings 41 as an example for illustration, at this time, the three metal rings 41 are the outer ring, the middle ring, and the inner ring from outside to inside. Nonlinear dielectric materials 42 are filled between the inner ring and the middle ring and between the middle ring and the outer ring, so that the inner ring, the middle ring, and the nonlinear dielectric material 42 therebetween form a first capacitor pair C1, and the middle ring, the outer ring, and the nonlinear dielectric material 42 therebetween form a second capacitor pair C₂. Taking the plate area of the first capacitor pair as 300 cm² as an example and the plate area of the second capacitor pair as 600 cm² as an example, the thickness of the nonlinear dielectric material 42 is 2 mm. The estimated low-field capacitance of the first capacitor pair is about 150 pF, and the estimated high-field capacitance of the first capacitor pair is about 0.6 nF; the estimated low-field capacitance of the second capacitor pair is about 270 pF, and the estimated high-field capacitance of the second capacitor pair is about 1.0 nF.

[0059] During use, the self-check module simultaneously monitors the states of the first capacitor pair C1 and the second capacitor pair C2, uses one of the first capacitor pair C1 and the second capacitor pair C2 as the main circuit, and the other capacitor pair as the backup circuit to achieve redundant design; when the main circuit alarms, it switches to the backup circuit to ensure reliable use.

[0060] Embodiment 4 Based on any one of Embodiments 1 to 3, this embodiment provides a multi-pin ionization lightning protection method based on a multi-layer heterogeneous composite electrode, including the following steps: Under the background thundercloud electric field, using the middle-layer field emission layer 30 coated with a high-field emission coefficient material coating 31, continuously generating an initial electron current and plasma through the field emission mechanism; Collecting and storing the charges in the initial electron current and plasma into the bottom-layer capacitive energy storage layer 40 through the impedance matching network 50; When the electric field of the thundercloud is enhanced to a preset threshold, the impedance matching network 50 automatically switches to a low impedance state, rapidly releasing the energy stored in the bottom capacitor energy storage layer 40 to the top needle array 20, thereby exciting the generation of an enhanced uplink leader.

[0061] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the scope of the invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0062] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can be appropriately combined to form other embodiments that can be understood by those skilled in the art. The above content is only for illustrating the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. Any modifications made based on the technical concept proposed in this invention shall fall within the scope of protection of the claims of this invention.

[0063] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A multi-needle ionization lightning arrester based on a multilayer heterogeneous composite electrode, characterized in that, Includes a support rod (10) and a multilayer heterogeneous composite electrode assembly disposed at the top of the support rod (10); The multilayer heterogeneous composite electrode assembly includes: Top-level needle tip array (20); The middle field emission layer (30) is located below the top tip array (20) and its surface is coated with a high field emission coefficient material coating (31). The bottom capacitor energy storage layer (40) is filled with nonlinear dielectric material (42) and is electrically connected to the middle field emission layer (30) through an impedance matching network (50); The top-level needle array (20) is electrically connected to the bottom-level capacitor energy storage layer (40).

2. The multi-needle ionization lightning arrester based on a multilayer heterogeneous composite electrode according to claim 1, characterized in that, The top-level needle tip array (20) includes a central main needle (21) and multiple peripheral auxiliary needles (22). The multiple peripheral auxiliary needles (22) are arranged circumferentially around the central main needle (21). The elevation angle of the peripheral auxiliary needles (22) is 25°~45°. The needle tip curvature radius of both the central main needle (21) and the peripheral auxiliary needles (22) is less than 0.3mm.

3. The multi-needle ionization lightning arrester based on a multilayer heterogeneous composite electrode according to claim 1, characterized in that, The middle field emission layer (30) includes multiple umbrella-shaped electrodes (32), which are all vertically spaced on the insulating pillar (11). The top needle array (20) is located at the top of the insulating pillar (11), and the bottom capacitor energy storage layer (40) is sleeved on the bottom of the insulating pillar (11). The bottom end of the insulating pillar (11) is connected to the top end of the support rod (10). The surfaces of the multiple umbrella-shaped electrodes (32) are coated with a high field emission coefficient material coating (31). The diameter of the umbrella-shaped electrodes (32) increases from top to bottom, and the distance between two adjacent umbrella-shaped electrodes (32) increases from top to bottom.

4. The multi-needle ionization lightning arrester based on a multilayer heterogeneous composite electrode according to claim 3, characterized in that, The high field emission coefficient material coating (31) is a carbon nanotube array, a graphene film, or a semiconductor material doped with rare earth metal oxides.

5. The multi-needle ionization lightning arrester based on a multilayer heterogeneous composite electrode according to claim 1, characterized in that, The bottom capacitor energy storage layer (40) is located below the middle field emission layer (30). The bottom capacitor energy storage layer (40) includes two metal rings (41). The two metal rings (41) are sequentially nested along their radial direction. The space between the two metal rings (41) is filled with a nonlinear dielectric material (42), so that the two adjacent metal rings (41) and the nonlinear dielectric material (42) between them form a capacitor pair.

6. The multi-needle ionization lightning arrester based on a multilayer heterogeneous composite electrode according to claim 1, characterized in that, The bottom capacitor energy storage layer (40) includes multiple metal rings (41), which are sequentially nested along their radial direction. A nonlinear dielectric material (42) is filled between two adjacent metal rings (41), so that the two adjacent metal rings (41) and the nonlinear dielectric material (42) filling between them form a capacitor pair.

7. The multi-needle ionization lightning arrester based on a multilayer heterogeneous composite electrode according to claim 5 or 6, characterized in that, The ratio of the dielectric constant of the nonlinear dielectric material (42) under high electric field to that under low electric field is not less than 3.

8. The multi-needle ionization lightning arrester based on a multilayer heterogeneous composite electrode according to claim 1, characterized in that, The intermediate field emission layer (30) is sleeved on the outside of the bottom capacitor energy storage layer (40). The outer wall of the intermediate field emission layer (30) is coated with a high field emission coefficient material coating (31). The inner wall of the intermediate field emission layer (30) and the bottom capacitor energy storage layer (40) are filled with a nonlinear dielectric material (42). The intermediate field emission layer (30), the bottom capacitor energy storage layer (40) and the nonlinear dielectric material (42) filling the space between them constitute a capacitor pair.

9. The multi-needle ionization lightning arrester based on a multilayer heterogeneous composite electrode according to claim 1, characterized in that, The impedance matching network (50) includes an air-core inductor, a damping resistor and a varistor, and the middle field emission layer (30) is electrically connected to the bottom capacitor energy storage layer (40) in sequence through the air-core inductor, the damping resistor and the varistor.

10. The multi-needle ionization lightning arrester based on a multilayer heterogeneous composite electrode according to claim 1, characterized in that, The vertical cross-section of the support column (10) is streamlined, and a spiral guide groove is provided on the support column (10).

11. The multi-needle ionization lightning arrester based on a multilayer heterogeneous composite electrode according to claim 1, characterized in that, It also includes a self-test module, which is used to assess the contamination or insulation degradation status of the bottom capacitor energy storage layer (40) by calculating the equivalent parallel resistance and equivalent capacitance of the bottom capacitor energy storage layer (40).

12. A lightning protection system for power transmission lines, characterized in that, A multi-needle ionization lightning arrester based on a multilayer heterogeneous composite electrode, as described in any one of claims 1 to 11, is installed on a tower in a lightning-prone area.

13. A multi-needle ionization lightning interception method based on a multilayer heterogeneous composite electrode, based on the multi-needle ionization lightning interception device based on a multilayer heterogeneous composite electrode as described in any one of claims 1 to 11, characterized in that, Includes the following steps: Under the background thundercloud electric field, an initial electron flow and plasma are continuously generated through the field emission mechanism by using a middle field emission layer (30) coated with a material coating (31) with a high field emission coefficient. The initial electron flow and the charge in the plasma are collected and stored in the bottom capacitor energy storage layer (40) through the impedance matching network (50); When the electric field of the thundercloud is enhanced to a preset threshold, the impedance matching network (50) automatically switches to a low impedance state, and quickly releases the energy stored in the bottom capacitor energy storage layer (40) to the top needle array (20), thereby exciting the generation of an enhanced uplink leader.

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