Lightning protection method for lightning stealth by field isolated electrified equipment based on uniform electric field theory

Abstract

The invention discloses a lightning protection method for lightning stealth of field isolated electrified equipment based on a uniform electric field theory. The lightning protection method comprises the following steps: analyzing a protection radius and a protection height required by the field isolated electrified equipment; lightning protection operation is carried out on the protection radius and the protection height of field isolated electrified equipment; a non-uniform electric field is changed into a relatively uniform electric field environment, so that protected equipment is not struck by lightning or is less struck by lightning, and the situation that electronic components or insulation of electrical equipment is damaged due to induced voltage generated when lightning current passes through a ground wire when a traditional lightning rod is used for electrified equipment is avoided; the problem of uniform electric field is solved in the form of electric charges, so that the cement pole tower and the like can conduct the electric charges without modifying the grounding grid when being mounted on the cement pole tower; the technology has an obvious effect on lightning protection of isolated live-line equipment in nature; the lightning protection principle of the technology supplements and perfects the lightning protection problem of modern electrified equipment, and has important significance for modern equipment safety and army field operation equipment.

Description

[0001] This application is a divisional application of a patent application entitled "A lightning protection technology for lightning invisibility of isolated live equipment in the field based on uniform electric field theory". The application date of the original application is November 15, 2018, and the application number is 201811357914.8. Technical Field

[0002] The present invention specifically relates to a lightning protection method for making isolated charged equipment in the field invisible to lightning based on the uniform electric field theory. Background Art

[0003] At present, the standard for lightning protection is based on the basic working principle of the lightning rod invented by American scientist Benjamin Franklin in 1749, which is to release lightning energy by attracting lightning to itself. This technology is applicable to protecting houses and buildings. With the development of modern industry, the use of the lightning rod principle is no longer suitable for lightning to operate with electricity and more stringent protection requirements for lightning protection objects. In this case, the instantaneous pulse induced voltage generated by the loop when the current is released through the ground wire will cause serious damage to electronic components. Irregular shaped objects and special shaped objects also have problems that are difficult to overcome in protection. For example, the protection of tall wind turbines and long-distance transmission lines has obvious problems that cannot be overcome in direct strikes, counterattacks, and bypass strikes. Statistics on the classification of power grid faults show that in the total number of trips in the operation of transmission and distribution lines, the number of trips caused by lightning strikes accounts for about 70%-80% of the total number of trips. Lightning disasters have become one of the three major factors that seriously affect the safety of power grid operation, along with natural disasters and external force damage. The live equipment running in the field is very easy to be struck by lightning. It has the "rod-plate" to produce an extremely uneven field environment to form conditions that are easy to discharge. The lightning conductor on the transmission line is based on the theory of traditional house lightning prevention to discharge lightning energy to protect the line. The problem of equipment failure caused by lightning overvoltage caused by lightning is very prominent, and it is urgent to carry out comprehensive and in-depth research to solve it. Isolated live equipment in nature refers to land and offshore wind turbines, transmission lines (wind farms are called collector lines), offshore work platforms, communication towers, mobile equipment in open areas, etc. are all targets that are easy to be struck by lightning. In a lightning environment, lightning rods or lightning conductors create an extremely uneven spatial electric field environment. The purpose of the working principle of lightning rods is to create targets that are very easy to be struck by lightning. This is like tearing a piece of paper. When a piece of paper has a gap, the stress will be concentrated at the gap. The lightning rod in a lightning environment is the gathering point of thundercloud discharge stress. Solving lightning disasters for wind turbines, transmission lines and other equipment is a global problem and a global problem. Summary of the invention

[0004] In view of this, the purpose of the present invention is to provide a lightning protection method for naturally isolated charged equipment by changing an extremely non-uniform electric field into a relatively uniform electric field environment to change the trajectory direction of the leader discharge so that the protected equipment is not struck by lightning or is less struck by lightning.

[0005] In order to solve the above problems, the technical solution of the present invention is: a lightning protection method for field isolated live equipment to hide lightning based on uniform electric field theory, comprising:

[0006] Select isolated live equipment in the field, analyze the protection radius and protection height required for the isolated live equipment in the field, and determine the protection radius and protection height required for the isolated live equipment in the field; when the isolated live equipment in the field is a transmission line, the protection radius needs to be increased; when the isolated live equipment in the field is a wind turbine, the protection radius needs to be increased; when the isolated live equipment in the field is a wind turbine blade, the protection radius, the adaptability height and the lightning protection performance under dynamic conditions need to be increased;

[0007] Based on the protection radius and protection height required by the isolated live equipment in the field, lightning protection operations are performed on the isolated live equipment in the field; wherein, when the isolated live equipment in the field is a collector line, it is necessary to increase the protection radius, and the needles are divided into three layers, including the first layer, the second layer and the third layer; when the isolated live equipment in the field is a wind turbine set, it has high requirements for vertical upward, and needles are installed on the front and back sides of each blade at an angle vertically within 45°, and needles are installed on the cabin.

[0008] Optionally, the needles of the first layer are in a vertical direction, the angle formed by the needles of the second layer and the vertical direction is greater than 45°, and the angle formed by the needles of the third layer and the vertical direction is greater than 70°.

[0009] Optionally, the distance between the 10.5kV towers of the transmission line is 50m, the distance between the 35kV towers of the transmission line is 100m-200m, the distance between the 220kV towers of the transmission line is 200m-300m, and the protection radius range of different voltage levels is 50m-150m.

[0010] Optionally, one needle is used in the first layer, seven needles are used in the second layer, and seven needles are used in the third layer.

[0011] Optionally, three needles are distributed on the front and back sides of each blade of the wind turbine generator set at an angle within 45° to the vertical direction, 18 needles are distributed on three blades, and 7 needles are distributed on the nacelle, for a total of 25 needles. When it is dynamic, the number of needles pointing upward is less than 25.

[0012] Optionally, when the distance between the pole towers of a 10.5kV line is 50m, the needle length is greater than 1.5m; when the distance between the pole towers of a 35kV line is 100-200m, the needle length is greater than 2.5m; when the distance between the pole towers of a 110kV line is 200-300m, the needle length is greater than 3m.

[0013] The beneficial effects of the present invention are as follows: by changing the extremely non-uniform electric field into a relatively uniform electric field environment, the trajectory direction of the leader discharge is changed, so that the protected equipment is not struck by lightning or is less struck by lightning, and the induced voltage generated by the lightning current through the ground wire when the live equipment uses a traditional lightning rod is avoided, which damages the electronic components or destroys the insulation of the electrical equipment; and the problem of uniform electric field is solved in the form of electric charge, so that cement poles and towers can conduct electric charges and can be installed on the cement poles and towers without modifying the grounding grid and grounding; the technology has an obvious effect on the lightning protection of isolated live equipment in nature; the lightning protection principle of the technology supplements and improves the lightning protection problem of modern live equipment, and is of great significance to the safety of modern equipment and military field equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is the installation method of lightning rod on the collector circuit.

[0015] Figure 2 This is the installation method of the lightning rod on the wind turbine blade.

[0016] Figure 3 This is the installation method of the lightning rod on the nacelle of a wind turbine.

[0017] Figure 4 Discharge conditions for normal units and units installed with lightning protection technology.

[0018] Figure 5 This is the discharge condition of two normal units. DETAILED DESCRIPTION

[0019] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0020] The explanation of stealth in stealth lightning protection technology: when the thundercloud is about 600 meters above the sky, it will produce a downward leader with the earth as the target. When the thundercloud is about 600 meters below the sky, it will produce a downward leader to a target on the ground. Its target is the object that produces an upward leader under the action of the thundercloud electric field. Modern industrial equipment, power transmission and distribution lines, communication towers, etc. are all objects that produce upward leaders. Stealth is the stealth effect caused by the downward leader not being able to find the upward leader, which is completely different from the principle of lightning rods in the prior art that release lightning energy by attracting lightning itself. The principle of lightning rods in the prior art is to attract lightning itself to release lightning energy to the earth through grounding, while the present invention macroscopically changes the extremely uneven electric field into a relatively uniform electric field environment, increases the breakdown voltage of thunderclouds to objects, and reduces stress concentration. Microscopically, it is through the fractal principle that the electric field strength generated by the upward leader charge of the object is suppressed to achieve the purpose of increasing the breakdown voltage, thereby avoiding lightning discharge to the protected object and achieving the "stealth" effect of objects such as transmission lines, towers and wind turbines. Through high-voltage physical simulation experiments, the use of stealth lightning protection technology based on uniform electric field can increase the breakdown voltage by 10%-15%, and reduce the probability of lightning strikes by more than 90%. The best lightning protection is achieved when the protected equipment is not struck by lightning or is less struck by lightning. Simply put, the lightning rod releases lightning energy to the earth in the form of current, and the lightning arrester suppresses the upward leader in the form of charge, and cement poles and towers do not need to be grounded.

[0021] The present invention discloses a lightning protection method for outdoor isolated charged equipment to conceal lightning based on the uniform electric field theory, comprising:

[0022] Select isolated live equipment in the field, analyze the protection radius and protection height required for the isolated live equipment in the field, and determine the protection radius and protection height required for the isolated live equipment in the field; when the isolated live equipment in the field is a transmission line, the protection radius needs to be increased; when the isolated live equipment in the field is a wind turbine, the protection radius needs to be increased; when the isolated live equipment in the field is a wind turbine blade, the protection radius, the adaptability height and the lightning protection performance under dynamic conditions need to be increased;

[0023] Based on the protection radius and protection height required by the isolated live equipment in the field, lightning protection operations are performed on the isolated live equipment in the field; wherein, when the isolated live equipment in the field is a collector line, it is necessary to increase the protection radius, and the needles are divided into three layers, including the first layer, the second layer and the third layer; when the isolated live equipment in the field is a wind turbine set, it has high requirements for vertical upward, and needles are installed on the front and back sides of each blade at an angle vertically within 45°, and needles are installed on the cabin.

[0024] Specifically, the lightning protection method includes analyzing the protection radius and protection height required for field isolated live equipment, and performing lightning protection operations on the protection radius and protection height of field isolated live equipment; the analysis of the protection radius and protection height required for field isolated live equipment is to have different emphases according to the lightning protection needs of different equipment. For example, the collection line needs to increase the protection radius, because the distance between the pole towers of the 10.5kV line is 50m, the tower distance of 35kV is 100-200m, and the tower distance of 110kV is 200-300m. Therefore, different protection objects have different problems that need to be solved. Therefore, we take the vertical direction of the needle, take the direction of 45° to the vertical direction, and take the direction of 70° to the vertical direction; the number of them is 1 vertical, 7 at 45°, and 7 at 70°. The installation method of the lightning rod on the collection line is as follows Figure 1 As shown, Figure 1 The bid number 1 is the collector line tower. Figure 1 The number 2 in the figure is a lightning rod. The wind turbine has low requirements for the protection radius, but high requirements for the vertical direction. There are 3 lightning rods on the front and back sides of each blade at an angle of 45° to the vertical, 6 on each side, 18 on 3 blades and 7 on the nacelle, a total of 25 needles. The lightning rod installation method on the blade is as follows: Figure 2 As shown, Figure 2 The number 3 in the middle is the blade. Figure 2 The number 4 in the middle is a lightning rod. The lightning rod on the nacelle is installed as follows: Figure 3 As shown, Figure 3 The number 5 in the middle is the engine room. Figure 3 The number 6 in the figure is a lightning rod. When it is dynamic, the upward needle is less than 25. The length of the needle is 1.5m based on the distance between the pole towers of the 10.5kV line of 50m, the needle length is 2.5m for the 35kV tower distance of 100-200m, and the needle length is 3m for the 110kV tower distance of 200-300m. The needle only needs to be connected to the original grounding system without adding any grounding grid modification. The cement pole tower cannot conduct current, but it is a conductor of charge. Therefore, there is no need to add grounding when installing it on the cement pole tower. The needle in the blade only needs to be connected to the lightning rod grounding wire, and the cabin is a conductor that can be installed.

[0025] According to the above scheme, relevant simulation tests were carried out in the high-voltage laboratory through the model to verify: the scale of the test model is 1:1000; the discharge height of thunderclouds in nature is generally in the range of 600 meters to 1000 meters. The vertical height of this test simulation is 800 meters, and the simulated vertical ground height in the laboratory is 800 mm; the horizontal distance between different wind turbine models is simulated to be 200 meters, and the simulated horizontal distance in the laboratory is 200 mm; the electric field of thunderclouds is simulated, and a negative electrostatic field is used; the actual breakdown voltage in nature is related to many natural conditions, but the proportional relationship is similar; different from the occurrence of lightning in nature, lightning can occur continuously in the laboratory, and the charge in nature only releases energy once, and there will be no second lightning; physical simulation tests are carried out, such as: the lightning protection effect of the modified wind turbine model is compared with that of the unmodified model, Figure 4 The discharge conditions of normal units and units equipped with lightning protection technology are as follows: Figure 4 The unit on the left in the middle is a normal unit. Figure 4 The unit on the middle right is the one equipped with lightning protection technology. Figure 5 The above experiment shows that the breakdown voltage of the modified wind turbine model is 15%-20% higher than that of the unmodified model, which is equivalent to changing the extremely non-uniform electric field (high-voltage technology calls the lightning rod "needle-plate" which can cause an extremely non-uniform electric field) into a relatively uniform electric field environment, and improving the "needle-plate" to "plate-plate"; the so-called "needle-plate" and "plate-plate" are physical phenomena of capacitors in physics; after high-voltage physical simulation tests, it is concluded that "the breakdown voltage increases gradually with each increase in the number of needles from 2 until it stops increasing after more than a dozen, and almost maintains the breakdown voltage from more than a dozen to more than 20, and the breakdown voltage begins to decrease when more needles are added after more than 20, and the breakdown voltage starts to decrease when the number of needles increases to nearly 50, which is basically the same as that of the lightning rod.

[0026] The beneficial effects of the present invention are: by changing the extremely non-uniform electric field into a relatively uniform electric field environment, the trajectory direction of the leader discharge is changed, so that the protected equipment is not struck by lightning or is less struck by lightning, and the induced voltage generated by the lightning current through the ground wire when the live equipment uses a traditional lightning rod is avoided, which damages the electronic components or destroys the insulation of the electrical equipment; and the problem of uniform electric field is solved in the form of electric charge, so that cement poles and towers can conduct electric charges and can be installed on cement poles and towers without modifying the grounding network; this technology has obvious effects on the lightning protection of isolated live equipment in nature; the lightning protection principle of this technology supplements and improves the lightning protection problems of modern live equipment, and is of great significance to the safety of modern equipment and military field equipment. The above is only a specific implementation method of the present invention, but the protection scope of the present invention is not limited to this, and any changes or replacements that are not conceived through creative labor should be covered within the protection scope of the present invention.

Claims

1. A lightning protection method for isolated charged equipment in the field to hide lightning based on uniform electric field theory, characterized in that: The lightning protection method for the lightning invisibility of isolated live equipment in the field based on the uniform electric field theory includes: Select isolated live equipment in the field, analyze the protection radius and protection height required for the isolated live equipment in the field, and determine the protection radius and protection height required for the isolated live equipment in the field; when the isolated live equipment in the field is a transmission line, the protection radius needs to be increased; when the isolated live equipment in the field is a wind turbine, the protection radius needs to be increased; when the isolated live equipment in the field is a wind turbine blade, the protection radius, the adaptability height and the lightning protection performance under dynamic conditions need to be increased; Based on the protection radius and protection height required by the isolated live equipment in the field, lightning protection operations are performed on the isolated live equipment in the field; wherein, when the isolated live equipment in the field is a collector line, it is necessary to increase the protection radius, and the needles are divided into three layers, including the first layer, the second layer and the third layer; when the isolated live equipment in the field is a wind turbine set, it has high requirements for vertical upward, and needles are installed on the front and back sides of each blade at an angle vertically within 45°, and needles are installed on the cabin.

2. A lightning protection method for isolated charged equipment in the field to hide lightning based on uniform electric field theory as claimed in claim 1, characterized in that: The needles of the first layer are in a vertical direction, the angle formed by the needles of the second layer with the vertical direction is greater than 45°, and the angle formed by the needles of the third layer with the vertical direction is greater than 70°.

3. A lightning protection method for isolated charged equipment in the field to hide lightning based on uniform electric field theory as claimed in claim 2, characterized in that: The 10.5kV tower spacing of the transmission line is 50m, the 35kV tower spacing of the transmission line is 100m-200m, the 220kV tower spacing of the transmission line is 200m-300m, and the protection radius range of different voltage levels is 50m-150m.

4. A lightning protection method for outdoor isolated charged equipment to hide lightning based on uniform electric field theory as claimed in claim 3, characterized in that: Take 1 needle from the first layer, 7 needles from the second layer, and 7 needles from the third layer.

5. A lightning protection method for outdoor isolated live equipment to hide lightning based on uniform electric field theory as claimed in claim 1, characterized in that: Each blade of the wind turbine generator set has three needles distributed on the front and back sides at an angle within 45° to the vertical direction, 18 needles on the three blades and 7 needles on the cabin, a total of 25 needles. When it is dynamic, the number of needles pointing upward is less than 25.

6. A lightning protection method for outdoor isolated live equipment to hide lightning based on uniform electric field theory as claimed in claim 3, characterized in that: When the distance between the pole towers of a 10.5kV line is 50m, the needle length is greater than 1.5m; when the distance between the pole towers of a 35kV line is 100-200m, the needle length is greater than 2.5m; when the distance between the pole towers of a 110kV line is 200-300m, the needle length is greater than 3m.

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