Arc extinguishing and lightning protection structure and method for improving arc discharge capacity

Abstract

The application discloses an arc-extinguishing lightning protection structure with improved arc discharge capacity, which comprises an arc-extinguishing chamber, a lightning electrode, a grounding electrode and a displacement electrode. The arc-extinguishing chamber is a relatively closed chamber structure, which is provided with a discharge port and an elastic inner wall made of elastic insulating material. The lightning electrode and the grounding electrode are oppositely arranged, and respectively inserted into the relatively closed chamber structure through the arc-extinguishing chamber and the elastic inner wall from outside of the arc-extinguishing chamber. The grounding electrode is fixed relative to the arc-extinguishing chamber, and the lightning electrode can slide relative to the arc-extinguishing chamber. One end of the lightning electrode in the chamber structure is connected with the displacement electrode, and the displacement electrode can slide in the chamber structure and block the discharge port. The arc-extinguishing lightning protection structure with improved arc discharge capacity can improve the arc-extinguishing threshold, and can avoid the invasion of dirt and ensure the clean environment of the arc-extinguishing chamber.

Description

Technical Field

[0001] This invention relates to the field of lightning protection technology, and in particular to an arc-extinguishing lightning protection structure and method for improving arc emission capability. Background Technology

[0002] Lightning strikes can cause various forms of damage and destruction to power facilities. To ensure the safe operation of the power system, lightning protection devices must be installed on both the power supply and demand sides. Existing lightning protection devices are mainly of two types: one is a lightning protection device with an arc-extinguishing chamber, such as the compact lightning protection arc-extinguishing chamber unit structure disclosed in patent application document CN201921142213.2; the other is a current-draining lightning protection device, such as a lightning rod. The two types operate on different principles. The arc-extinguishing lightning protection device utilizes the nonlinear resistance characteristics of metal oxides to eliminate the arc and current during a lightning strike, thus achieving lightning protection. The lightning rod type, on the other hand, uses the tip discharge of the lightning rod to divert the charge from the clouds to the ground, preventing direct lightning strikes to buildings. Lightning protection devices with arc-extinguishing chambers are suitable for higher lightning voltage levels and are generally used in high-voltage power systems, communication systems, radar systems, etc. Lightning rod lightning protection devices are suitable for low and medium lightning voltage levels and are generally used in buildings, utility poles, bridges, etc.

[0003] The arc-extinguishing threshold of a lightning protection device is a crucial indicator. It refers to the threshold at which the device can effectively suppress lightning current and prevent electric shock under lightning strike conditions. For lightning arresters with arc-extinguishing chambers, the arc-extinguishing threshold is significantly affected by the cleanliness of the chamber environment. Because existing arc-extinguishing chamber structures are designed to expel energy during arc extinguishing, they typically include nozzles connected to the chamber, compromising the cleanliness of the chamber environment. This leads to a decrease in the arc-extinguishing threshold over time, affecting arc-extinguishing capability and compromising power safety on both the supply and demand sides. Summary of the Invention

[0004] To address the aforementioned problems, this invention provides an arc-extinguishing and lightning protection structure and method that enhances arc emission capacity, thereby increasing the arc-extinguishing threshold. While improving arc emission capacity, it also prevents contaminant intrusion, ensuring a clean environment within the arc-extinguishing chamber.

[0005] The technical solution adopted in this invention is as follows:

[0006] An arc-extinguishing lightning protection structure for improving arc discharge capability is disclosed. This structure includes an arc-extinguishing chamber, a lightning arresting electrode, a grounding electrode, and a displacement electrode. The arc-extinguishing chamber is a relatively enclosed cavity structure with a discharge port and an elastic inner wall made of elastic insulating material. The lightning arresting electrode and the grounding electrode are positioned opposite each other, penetrating the arc-extinguishing chamber and the elastic inner wall, respectively, and inserted into the relatively enclosed cavity structure. The grounding electrode is fixed relative to the arc-extinguishing chamber, while the lightning arresting electrode can slide relative to the arc-extinguishing chamber. One end of the lightning arresting electrode within the cavity structure is connected to the displacement electrode, which can slide within the cavity structure and block the discharge port.

[0007] Furthermore, the arc-extinguishing chamber is fitted with an external insulating skirt.

[0008] Furthermore, an external limiting component is installed at the end of the lightning electrode outside the arc extinguishing chamber; an internal limiting component is also provided inside the chamber structure to limit the maximum sliding position of the displacement electrode.

[0009] Furthermore, a strong damping structure is installed between the displacement electrode and the inner wall of the arc-extinguishing chamber.

[0010] Furthermore, the strong damping structure is a damping spring.

[0011] An arc-extinguishing lightning protection method for improving arc emission capacity is disclosed. Based on the aforementioned arc-extinguishing lightning protection structure for improving arc emission capacity, this method involves setting an elastic inner wall made of elastic insulating material inside the arc-extinguishing chamber. During arc extinguishing, the elastic inner wall deforms, causing the radial pressure of the arc to change into axial pressure, resulting in an isotropic, extremely high pressure arc within the arc-extinguishing chamber. Furthermore, the method incorporates sliding ground electrodes and displacement electrodes, allowing the displacement electrodes to cooperate with the discharge port of the arc-extinguishing chamber to form a discharge valve structure. This discharge valve structure is normally closed, keeping the arc-extinguishing chamber closed. During arc extinguishing, the discharge valve structure opens under pressure, allowing the high-temperature, high-pressure gas within the chamber to be discharged through the discharge port.

[0012] Furthermore, this arc-extinguishing and lightning protection method to improve arc emission capability includes:

[0013] Step 1: Establish a two-dimensional axisymmetric model of SCCS-intercepted arc;

[0014] Step 2: Simulation is performed based on the two-dimensional axisymmetric model of the SCCS arc extinguishing device to establish the pressure change curve in the arc extinguishing chamber through simulation.

[0015] Step 3: Based on the pressure change curve, obtain the maximum pressure, and calculate the impact force on the electrode based on the maximum pressure and the cross-sectional area of ​​the arc-extinguishing chamber.

[0016] Step 4: Based on the impact force on the electrode, the mass of the lightning electrode, the moving electrode, or the maximum elastic force of the strong damping structure, infer whether the valve structure can be opened.

[0017] Furthermore, when the arc-extinguishing and lightning protection structure that enhances arc emission capability is installed horizontally, the discharge valve structure is kept normally closed by a strong damping structure, and when installed vertically, it is kept normally closed by the weight of the displacement electrode and the lightning rod itself.

[0018] Furthermore, this arc-extinguishing and lightning protection method, which enhances arc emission capacity, generates an arc-extinguishing process that first increases the voltage and then discharges the arc.

[0019] The beneficial effects of this invention are:

[0020] This arc-extinguishing and lightning protection structure, which enhances arc discharge capability, makes the lightning arrestor and displacement electrode slideable. This allows the displacement electrode to cooperate with the discharge port of the arc-extinguishing chamber to form a discharge valve structure, thereby preventing contaminant intrusion. The valve is only opened momentarily during the arc-extinguishing process and remains closed during the non-arc-extinguishing cycle. This prevents dust, insects, and moisture from entering the arc-extinguishing chamber, ensuring its cleanliness and increasing the arc-extinguishing threshold.

[0021] This arc-extinguishing and lightning protection structure, which improves arc emission capacity, enhances arc extinguishing characteristics by installing an elastic inner wall made of elastic insulating material inside the arc extinguishing chamber. This increases the peak arc extinguishing pressure and reduces the peak pressure time inside the arc extinguishing chamber, resulting in an increased arc extinguishing threshold and a shorter arc extinguishing time. By reducing the duration of large arcs, it avoids lightning tripping and line breakage.

[0022] The arc-extinguishing and lightning protection structure, which enhances the arc emission capacity, can also change the arc emission direction through its elastic inner wall. The arc emission direction and the arc-extinguishing chamber direction are at a 90-degree angle, forming a sudden change point in the arc path and improving the ability to suppress arc reignition. Attached Figure Description

[0023] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the following description of the embodiments will be briefly introduced. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] in:

[0025] Figure 1 and Figure 2 This is a schematic diagram of the arc-extinguishing lightning protection structure when it is installed vertically.

[0026] Figure 3 and Figure 4 A schematic diagram of a horizontally installed arc-extinguishing lightning protection structure;

[0027] Figure 5 This is a graph showing the pressure change.

[0028] In the diagram, 1—arc extinguishing chamber, 2—lightning electrode, 3—grounding electrode, 4—displacement electrode, 5—discharge port, 6—elastic inner wall, 7—outer insulating skirt, 8—outer limiting component, 9—inner limiting component, 10—strong damping structure. Detailed Implementation

[0029] 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. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0030] Example 1

[0031] Existing lightning protection devices with arc-extinguishing chambers use nozzle structures that communicate with the arc-extinguishing chambers, which cannot guarantee a clean environment inside the arc-extinguishing chambers. As a result, the arc-extinguishing threshold decreases after long-term use, affecting the arc-extinguishing capability and failing to guarantee the power supply and demand safety. This embodiment provides an arc-extinguishing lightning protection structure that improves the arc emission capability.

[0032] like Figure 1 and Figure 2 As shown, this high arc-emission lightning protection structure consists of an arc-extinguishing chamber 1, a lightning arresting electrode 2, a grounding electrode 3, and a displacement electrode 4. The arc-extinguishing chamber 1 is a relatively enclosed cavity structure, cylindrical in shape, with an exhaust port 5 on its surface. The exhaust port 5 is at a 90-degree angle to the arc-extinguishing chamber 1, creating a sudden change in the arc path and improving the ability to suppress arc reignition. The interior of the arc-extinguishing chamber 1 has an elastic inner wall 6 made of elastic insulating material. To ensure the insulation of the arc-extinguishing chamber 1, an outer insulating skirt 7 is fitted around its exterior. The lightning electrode 2 and the grounding electrode 3 are positioned opposite each other, penetrating the arc-extinguishing chamber 1 and the elastic inner wall 6 from the outside and being inserted into a relatively enclosed cavity structure. The grounding electrode 3 is fixed relative to the arc-extinguishing chamber 1, while the lightning electrode 2 can slide relative to the arc-extinguishing chamber 1. One end of the lightning electrode 2 inside the cavity structure is connected to a displacement electrode 4, which can slide within the cavity structure. The lightning electrode 2, the grounding electrode 3, and the displacement electrode 4 are all made of conductive metal, and the displacement electrode 4 is a cylindrical electrode with a diameter matching the inner diameter of the cavity structure. An external limiting member 8 is installed at the end of the lightning electrode 2 outside the arc-extinguishing chamber 1; an internal limiting member 9 is also provided inside the cavity structure to limit the maximum sliding position of the displacement electrode 4, thereby limiting the maximum sliding positions of the lightning electrode 2 and the displacement electrode 4.

[0033] The arc-extinguishing principle of this high-arc emission capacity arc-extinguishing lightning protection structure is as follows:

[0034] like Figure 1 As shown, when a lightning strike occurs, the lightning current enters the arc-extinguishing chamber 1 through the lightning electrode 2, and is transmitted from the displacement electrode 4 towards the grounding electrode 3, where arc extinguishing occurs between the displacement electrode 4 and the grounding electrode 3. During the arc extinguishing process, high-temperature and high-pressure gas is generated, increasing the gas pressure within the chamber structure. This pushes the displacement electrode 4 and the lightning electrode 2 upwards, causing the discharge valve structure to open, allowing the high-temperature and high-pressure gas within the chamber structure to be discharged through the discharge port 5. After the high-temperature and high-pressure gas is discharged, the discharge valve structure returns to its normal state; that is, the lightning electrode 2 and the displacement electrode 4 move downwards under their own weight, and the displacement electrode 4 seals the discharge port 5 of the arc-extinguishing chamber 1, keeping the chamber structure of the arc-extinguishing chamber 1 in a closed state. This prevents contamination, dust, insects, and moisture from entering the arc-extinguishing chamber 1, ensuring its cleanliness and thus increasing the arc-extinguishing threshold.

[0035] Furthermore, since the arc-extinguishing chamber 1 is equipped with an elastic inner wall 6 made of elastic insulating material, the expansion pressure generated by the arc heating the air medium after the arc is injected into the arc-extinguishing chamber 1 and the reaction pressure of the arc radially contracting due to the deformation of the elastic inner wall 6 are superimposed and act on the elastic inner wall 6 of the arc-extinguishing chamber 1. First, the elastic inner wall 6 is compressed, causing the inner diameter of the chamber structure to expand and increase. Then, the elastic inner wall 6 rebounds, causing the inner diameter of the chamber structure to contract and become thinner. The radial pressure of the arc is converted into axial pressure, so that the arc in the arc-extinguishing chamber 1 is in an isotropic and extremely high pressure, thereby producing an arc-extinguishing process of first increasing the pressure and then releasing the arc.

[0036] The pressurization of arc-extinguishing chamber 1 mainly comes from: 1. Under normal conditions, the diameter of the chamber structure of arc-extinguishing chamber 1 is small, and the arc shape deforms during the arc injection process, thus increasing the pressure; 2. The elastic inner wall 6 deforms and rebounds, thus increasing the pressure; 3. The temperature rise and volume expansion of the medium inside the chamber structure increase the pressure; 4. The expansion pressure diffuses in a wave pattern and is reflected through the inner wall of arc-extinguishing chamber 1, increasing the pressure; 5. Due to the discharge valve structure, the pressure is increased at the discharge port 5 of arc-extinguishing chamber 1. The arc-extinguishing process of first increasing the pressure and then discharging the arc has the following advantages: 1. It increases the pressure accumulation and rapid discharge energy and pressure gradient in arc-extinguishing chamber 1, increases the accumulated pressure and the rate of pressure rise in arc-extinguishing chamber 1, and advances the time point of arc extinguishing to reduce the duration and intensity of the arc; 2. It increases the arc extinguishing speed and arc extinguishing threshold, and the discharge valve structure can increase the discharge pressure threshold in arc-extinguishing chamber 1. 3. Improve arc extinguishing characteristics. The peak arc extinguishing pressure in arc extinguishing chamber 1 increases and the peak pressure time decreases, resulting in an increase in the arc extinguishing threshold and a decrease in the arc extinguishing time. This creates an asymmetric advantage between the arc extinguishing pressure and the arc resistance to increase the pressure, thereby reducing the duration of the large arc and avoiding lightning tripping and line breakage.

[0037] Based on the above-mentioned arc-extinguishing and lightning protection structure with high arc emission capacity, this embodiment also proposes an arc-extinguishing and lightning protection method to improve arc emission capacity, as follows:

[0038] Step 1: Establish a two-dimensional axisymmetric model of the SCCS-intercepted arc:

[0039] Before building the model, assume that the arc plasma satisfies the following conditions:

[0040] (1) Arc plasma is thermal plasma that satisfies the local thermodynamic equilibrium condition;

[0041] (2) An electric arc is a free gas at high temperature. Its thermal conductivity, electrical conductivity, heat capacity, constant pressure and viscous dissipation loss are single-valued functions of temperature.

[0042] (3) Assume that the electric arc fluid is laminar and compressible;

[0043] (4) Neglect the melting of the metal electrode;

[0044] (5) The initial generation process of electric arc plasma is not considered;

[0045] Under the above assumptions, a two-dimensional axisymmetric model of SCCS truncation of electric arc with an outer diameter of 20 mm and an inner diameter of 5 mm is established, which is equivalent to arc extinguishing chamber 1.

[0046] Step 2: Simulation is performed based on a two-dimensional axisymmetric model of the SCCS arc interruption. The simulation uses a 20kA 8 / 20μs lightning current waveform coupled with a 1.5kA power frequency current, and the inner diameter of the arc-extinguishing tube is 5mm. The pressure change curve inside the arc-extinguishing chamber is established through simulation, as shown in the figure below. Figure 5 As shown.

[0047] Step 3: As shown in the pressure change diagram inside the arc-extinguishing tube, after the high-current impact arc breaks down the air gap and enters the SCCS arc-extinguishing tube, it compresses the gas inside the tube and causes its temperature to rise. Around 17 µs, the highest temperature of the arc column exceeds 25,000 K. The increase in temperature causes an increase in the density of the medium, which in turn increases the pressure inside the tube. The pressure inside the arc-extinguishing chamber reaches its maximum value of 5.03 MPa at 8 µs.

[0048] Since the inner diameter of the arc-extinguishing tube is set to 5mm in the simulation, the impact force on the electrode is:

[0049] F1 = PS = Pπr 2 =5.03×10 6 ×0.0025 2 π≈98N

[0050] In the formula: P is the maximum pressure inside the arc-extinguishing chamber, and S is the cross-sectional area of ​​the arc-extinguishing chamber; since the arc-extinguishing chamber is a cylindrical structure, it can be calculated using the radius r of its cross-section.

[0051] In practical applications, the inner diameter of the arc-extinguishing chamber can be designed to be 8mm. If the maximum pressure is taken as 1MPa, the impact force is still: F1=PS=Pπr 2 =1×10 6 ×0.004 2 π≈50N;

[0052] Step 4, taking a displacement electrode with a radius of 4mm and a length of 2mm, and a lightning electrode with a radius of 1.5-2.5mm and a length of 20-30mm as an example, the material can be carbon steel with a density of approximately 7.85g / cm³. 3 Then we have:

[0053]

[0054]

[0055] In the formula: m is the total mass of the displacement electrode and the lightning rod, V is the total volume of the displacement electrode and the lightning rod, ρ is the density of the displacement electrode and the lightning rod, r1 is the radius of the displacement electrode, h1 is the length of the displacement electrode, r2 is the radius of the lightning rod, and h2 is the length of the lightning rod.

[0056] It can be determined that the total weight of the displacement electrode and the lightning rod is approximately 2-6g, and the gravitational force (gravitational constant g is taken as 10) is also present.

[0057] G = mg = 0.002 × 10 = 0.02 N

[0058] G = mg = 0.006 × 10 = 0.06 N

[0059] The total weight of the displacement electrode and the lightning rod is less than 1N. Based on the impact force calculated in step 3, the impact force is more than 50 times the total weight, which can push the displacement electrode and the lightning rod out.

[0060] Example 2

[0061] In practical applications, the arc-emission capacity arc-extinguishing lightning protection structure may not be able to be installed vertically due to factors such as installation location and space. Therefore, to ensure the proper functioning of the internal discharge valve structure when the arc-emission capacity arc-extinguishing lightning protection structure is not vertically installed, such as horizontally, based on Example 1, as follows... Figure 3 and Figure 4 As shown, a strong damping structure 10 can also be installed between the displacement electrode 4 and the inner wall of the arc-extinguishing chamber 1. The strong damping structure 10 can be a damping spring.

[0062] During the arc extinguishing process, high-temperature and high-pressure gas is generated, which increases the gas pressure inside the chamber structure. This pushes the displacement electrode 4 and the lightning rod 2 upward, causing the discharge valve structure to open. At the same time, the damping spring is compressed, allowing the high-temperature and high-pressure gas inside the chamber structure to be discharged through the discharge port 5. After the high-temperature and high-pressure gas is discharged, the discharge valve structure returns to its normal state through the action of the damping spring. The displacement electrode 4 seals the discharge port 5 of the arc extinguishing chamber 1, keeping the chamber structure of the arc extinguishing chamber 1 in a closed state. This prevents the intrusion of contaminants, dust, insects, and moisture into the arc extinguishing chamber 1, ensuring its cleanliness and thus increasing the arc extinguishing threshold.

[0063] When the arc-emission capacity arc-extinguishing lightning protection structure is installed horizontally, steps 1 to 3 in the method for improving the arc-emission capacity are the same as when it is installed vertically.

[0064] Step 4, taking a damping spring length l of 2-3 cm as an example, the deformation x is 1.5-2.5 cm. According to Hooke's Law: F2 = kx

[0065] It can be seen that when the damping spring stiffness coefficient is less than 2000 N / m, the maximum spring force of the damping spring is less than 50 N, and the impact force is sufficient to push the displacement electrode and the lightning rod out.

[0066] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. An arc-extinguishing and lightning protection structure for improving arc emission capability, characterized in that: The arc-extinguishing lightning protection structure for improving arc discharge capability includes an arc-extinguishing chamber, a lightning rod, a grounding electrode, and a displacement electrode. The arc-extinguishing chamber is a relatively closed cavity structure with a discharge port and an elastic inner wall made of elastic insulating material. The lightning rod and the grounding electrode are arranged opposite each other, respectively inserted into the relatively closed cavity structure through the outside of the arc-extinguishing chamber and the elastic inner wall. The grounding electrode is fixed in position relative to the arc-extinguishing chamber, while the lightning rod can slide relative to the arc-extinguishing chamber. One end of the lightning rod inside the cavity structure is connected to the displacement electrode, which can slide within the cavity structure and block the discharge port.

2. The arc-extinguishing and lightning protection structure for improving arc emission capacity according to claim 1, characterized in that: The arc-extinguishing chamber is fitted with an external insulating skirt.

3. The arc-extinguishing and lightning protection structure for improving arc emission capacity according to claim 1, characterized in that: The lightning electrode is also equipped with an external limiting component at its end outside the arc extinguishing chamber; the chamber structure is also equipped with an internal limiting component to limit the maximum sliding position of the displacement electrode.

4. The arc-extinguishing and lightning protection structure for improving arc emission capacity according to claim 1, characterized in that: A strong damping structure is also installed between the displacement electrode and the inner wall of the arc extinguishing chamber.

5. The arc-extinguishing and lightning protection structure for improving arc emission capacity according to claim 4, characterized in that: The strong damping structure is a damping spring.

6. A method for arc extinguishing and lightning protection that improves arc emission capacity, based on the arc extinguishing and lightning protection structure for improving arc emission capacity as described in any one of claims 1-4, characterized in that: This arc-extinguishing and lightning protection method for improving arc emission capacity involves installing an elastic inner wall made of elastic insulating material inside the arc-extinguishing chamber. During arc extinguishing, the elastic inner wall deforms, converting the radial pressure of the arc into axial pressure, placing the arc within the chamber under isotropic and extremely high pressure. Furthermore, the method incorporates sliding ground electrodes and displacement electrodes, creating a discharge valve structure between the displacement electrode and the discharge port of the arc-extinguishing chamber. This discharge valve structure is normally closed, keeping the arc-extinguishing chamber sealed. During arc extinguishing, the valve opens under pressure, allowing the high-temperature, high-pressure gas within the chamber to escape through the discharge port.

7. The arc-extinguishing and lightning protection method for improving arc emission capacity according to claim 6, characterized in that: The arc-extinguishing and lightning protection methods that improve arc emission capabilities include: Step 1: Establish a two-dimensional axisymmetric model of the arc-extinguishing chamber; Step 2: Simulation is performed based on a two-dimensional axisymmetric model to establish a pressure change curve in the arc-extinguishing chamber. Step 3: Based on the pressure change curve, obtain the maximum pressure, and calculate the impact force on the electrode based on the maximum pressure and the cross-sectional area of ​​the arc-extinguishing chamber. Step 4: Based on the impact force on the electrodes, the mass of the lightning electrode and the displacement electrode, or the maximum elastic force of the strong damping structure, infer whether the valve structure can be opened.

8. The arc-extinguishing and lightning protection method for improving arc emission capacity according to claim 6, characterized in that: When the arc-extinguishing and lightning protection structure that enhances arc discharge capability is installed horizontally, the discharge valve structure is kept normally closed by a strong damping structure. When installed vertically, it is kept normally closed by the weight of the displacement electrode and the lightning rod itself.

9. The arc-extinguishing and lightning protection method for improving arc emission capacity according to claim 6, characterized in that: This arc-extinguishing and lightning protection method, which improves the arc emission capacity, involves an arc-extinguishing process in which the arc is first boosted and then discharged.

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