Method for predicting lightning attachment point caused by ship

Abstract

The invention relates to the technical field of ship thunder and lightning protection effect verification and evaluation, in particular to a method for predicting thunder and lightning attachment points caused by a ship. According to the method for predicting the thunder and lightning attachment points caused by the ship, the thunder and lightning attachment test of the ship scale model of thunder and lightning caused by the ship is carried out, so that the areas and positions of equipment such as a ship deck, a small mast, an antenna, a head anchor lamp and a tail lamp which are subjected to thunder and lightning attachment or breakdown can be obtained, and then the thunder and lightning attachment probability of ship surface equipment is accurately predicted; and meanwhile, lightning attachment areas where the ship triggers lightning strokes are divided according to test results, so that support can be provided for lightning protection of equipment and parts in each lightning subarea of the ship.

Description

Technical Field

[0001] The present invention relates to the technical field of ship lightning protection effect verification and evaluation, and in particular to a method for predicting lightning attachment points caused by ships. Background Art

[0002] Lightning is a natural phenomenon of ultra-long gap discharge, with the characteristics of high voltage amplitude, high current intensity, and strong destructive power. The ocean is an area where lightning is extremely likely to form. Ships sailing on the vast sea, their towering masts and various shipborne antennas and other protruding structures are targets that are easily attacked by lightning on the sea. Once a ship is struck by lightning, it is easy to cause damage to the ship's sensitive devices, equipment and systems, affecting navigation safety and mission execution. Therefore, it is necessary to carry out ship lightning protection design and evaluate the lightning strike risk of key parts of the ship and the protection effect of lightning rods.

[0003] At present, the method of direct lightning protection for ships is mostly to install lightning rods, and their protection range is generally determined by the "rolling ball method". However, the development process of lightning strikes and the attachment targets are random, and it is difficult to directly obtain the probability distribution of lightning attachment in different parts of the ship through theoretical analysis. In the existing marine regulations, the relevant provisions on how to determine the protection area of ​​the lightning rod and the height of the lightning rod on the metal hull are not sufficient. Therefore, it is necessary to carry out ship lightning attachment point tests, which are of great significance for supporting lightning protection design, evaluating the lightning strike risk of key parts of the ship and the protection effect of lightning rods. Summary of the invention

[0004] The technical problem to be solved by the present invention is: to propose a method for predicting the attachment points of lightning caused by ships. By conducting a lightning attachment test on a scaled model of a ship caused by lightning strikes by a ship, the areas, positions and times of lightning attachment or breakdown on the ship deck and various equipment and components on the deck can be statistically analyzed to support the design of ship lightning protection.

[0005] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0006] A method for predicting lightning attachment points caused by ships mainly includes:

[0007] S1, ship-induced lightning strike simulation: a flat plate electrode of preset size is used to simulate the lightning strike caused by a ship;

[0008] S2, making test pieces: using conductive metal materials to make a scaled model of a ship, and using a metal plate of preset thickness to simulate the seawater equivalent plane;

[0009] S3, test arrangement: an impulse voltage generator is connected to the flat electrode to generate a simulated lightning strike, a digital storage oscilloscope is used to record the discharge polarity, voltage amplitude and waveform, and an optical camera is used to record the discharge arc path and attachment point;

[0010] S4, test waveform: the amplitude of the test waveform is determined according to whether the gap between the test piece and the flat electrode is broken down or flashed over the test piece;

[0011] S5, determining the test steps: performing impact discharge on the scaled model of the ship according to the preset test steps to complete the simulation test;

[0012] S6, Test records and data analysis: record the test data and conduct statistical analysis to obtain the locations where the lightning is attached or penetrated by the ship's equipment and components when the ship is struck by lightning, as well as the corresponding probability of lightning attachment at each location.

[0013] Furthermore, the ship lightning protection adopts a striking distance of 30m, and the length and width of the flat electrode are 13m and 3m respectively.

[0014] Furthermore, the scaling ratio of the scaled-down model of the ship is 1 / 20, and the distance between the flat electrode and the highest point on the surface of the scaled-down model of the ship is 1.5 m.

[0015] Furthermore, the high voltage end of the impulse voltage generator is connected to the flat electrode, the scaled model of the ship is placed on a grounded metal plate simulating a seawater equivalent plane, and the ground end of the impulse voltage generator is directly connected to the grounded metal plate.

[0016] Furthermore, the output voltage of the impulse voltage generator is sent to an oscilloscope via a coaxial cable after passing through a voltage divider to record the discharge polarity, voltage amplitude and waveform of the flat electrode.

[0017] Furthermore, the optical cameras are specifically provided in multiple units to record the positions of attachment points on the model at different angles.

[0018] Furthermore, the impulse voltage of the impulse voltage generator specifically adopts an impulse voltage waveform with a rise time of 50 to 250 μs to simulate a lightning strike caused by a ship.

[0019] Furthermore, the test steps include:

[0020] S51, measuring test environmental conditions: the environmental conditions include temperature, humidity, and atmospheric pressure;

[0021] S52, check the test equipment and perform safety procedures: before charging the test equipment, personnel must be evacuated, and before personnel re-enter the test area, the capacitor bank of the impulse voltage generator must be grounded;

[0022] S53, selecting a flat electrode of a preset size to complete the layout of the test equipment;

[0023] S54, Calibration of impulse voltage generators and measuring instruments;

[0024] S55, performing an impact discharge on the model, and immediately checking the photos taken by the optical camera after the discharge to ensure that the attachment point of the arc on the model can be clearly identified in the photos;

[0025] S56, performing a preset number of discharge tests on the model.

[0026] Furthermore, the recording of test data includes:

[0027] S61, record the temperature, humidity and atmospheric pressure data of the test environment;

[0028] S62, recording the test number, polarity of the plate electrode, discharge voltage, and waveform number;

[0029] S63, record photos and descriptions of each discharge test;

[0030] S64, fill in the test operators and witnesses;

[0031] S65, count and analyze the coordinates of each lightning attachment point to obtain the probability of the ship's equipment and components being struck by lightning under the natural lightning leader.

[0032] Furthermore, when the distance between the flat plate electrode and the highest point on the surface of the scaled ship model is 1.5 m, 2 m and 1 m, the test steps are respectively carried out, and the test results are compared and analyzed.

[0033] Compared with the prior art, the present invention has the following main advantages:

[0034] The present invention proposes a method for predicting lightning attachment points caused by a ship. By conducting a lightning attachment test on a scaled model of a ship caused by lightning strikes, the areas and positions where equipment such as the ship's deck, small mast, antenna, bow anchor light, and stern light are attached or broken down by lightning can be obtained, thereby accurately predicting the lightning attachment probability of the deck equipment. At the same time, the lightning attachment areas caused by lightning strikes on ships are divided according to the test results, which can provide support for lightning protection of equipment and components in each lightning zone of the ship. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 This is a schematic diagram of a configuration for simulating a lightning strike test caused by a ship in an embodiment of the present invention;

[0036] Figure 2 This is a schematic diagram of wiring and arrangement for simulating a lightning strike test caused by a ship in an embodiment of the present invention;

[0037] Figure 3 This is a voltage waveform diagram with a rise time of 50 to 250 μs in an embodiment of the present invention;

[0038] Figure 4 is the number of the lightning attachment position of the ship model in the embodiment of the present invention;

[0039] Figure 5 Schematic diagram of a typical discharge voltage waveform in an embodiment of the present invention. DETAILED DESCRIPTION

[0040] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0041] It should be pointed out that, according to the needs of implementation, the various steps / components described in this application can be split into more steps / components, and two or more steps / components or partial operations of steps / components can be combined into new steps / components to achieve the purpose of the present invention.

[0042] Embodiment 1: This embodiment provides a method for predicting the lightning attachment point caused by a ship, which is as follows:

[0043] 1. Simulation of lightning strikes caused by ships

[0044] Thunderstorms usually occur when there are strong moist warm air currents. The cloud base height is generally 1 to 3 km, with the lowest reaching 150 m and the highest reaching more than ten kilometers. The average height of its main negative charge center is about 3 km.

[0045] The electrical geometry model assumes that before a thundercloud flashes to the ground (or a building), the leader that develops from the thundercloud to the ground must reach a certain range from the lightning strike point. It is generally believed that only when the thundercloud develops to a distance of several hundred meters from the struck object can the tall objects on the ground affect the development of the discharge channel. The distance between the leader point and the strike point is called the strike distance, which is the final stage of the leader development. The position of the leader head is irrelevant to the lightning strike object when it is greater than the strike distance. According to the test requirements, the distance of the lightning strike to the ground should be greater than the strike distance under the corresponding lightning current.

[0046] Model testing is an effective method to determine the lightning attachment point. This test uses a flat electrode to simulate a lightning strike caused by a ship. The typical test configuration is shown in Figure 1 The scale of the model in this experiment is 1 / 20. The experiment simulates the direction in which the lightning leader may enter during the voyage of the ship. This is achieved by adjusting the model's posture and changing the position of the electrodes.

[0047] The ship lightning protection adopts a striking distance of 30m. According to the scale ratio of 1 / 20, the distance h between the high-voltage electrode and the highest point on the surface of the nearest ship model is 1.5m. In addition, distances of 1m and 2m are added for comparison.

[0048] 2. Test piece

[0049] The test piece is a scaled-down model of the original ship's external structure, and the outer surface of the test model is a conductive metal structure. The full-metal ship model is made of metal sheets, and the metal parts such as the hull, cabin, lightning rod, antenna tower, shortwave antenna, etc. are consistent with the ship's external space structure, conductor material and electric field layout. The scaled-down model has a scale ratio of 1 / 20, and the corresponding length, width and height of the model are approximately 8.9m, 0.9m and 1.9m respectively.

[0050] A metal aluminum plate with a thickness of 1 mm is used to simulate the seawater equivalent plane, and its length and width are 13 m and 3 m respectively.

[0051] The length and width of the flat high voltage electrode are 13m and 3m respectively.

[0052] 3. Experimental arrangement

[0053] An impulse voltage generator is used to generate a lightning simulation leader, a digital storage oscilloscope is used to record the discharge polarity, voltage amplitude and waveform, and an optical camera is used to record the discharge arc path and attachment point.

[0054] The layout and wiring diagram of the test for simulating the attachment of lightning leaders caused by ships are shown in Figure 2 The flat high-voltage electrode is connected to the high-voltage end of the impulse voltage generator. The ship model is placed on a grounded metal plate simulating the equivalent plane of seawater, and the return line of the impulse voltage generator is connected to the grounded metal plate. The output voltage of the impulse voltage generator is sent to the oscilloscope through a coaxial cable after passing through a voltage divider for measurement. Two still cameras with adjustable exposure time are used to distinguish the attachment point positions on the model at different angles.

[0055] 4. Test waveform

[0056] The lightning test simulating the ship-induced lightning strike uses an operating impulse voltage waveform with a rise time of 50 to 250 μs, see Figure 3 The amplitude of the test waveform is determined by the breakdown of the test piece or the flashover sliding over the test piece, and a 50% breakdown voltage of 1.2 times the gap is applied to ensure that the gap can be broken down each time the test is carried out.

[0057] 5. Determine the test steps

[0058] 1) Measure the test environment conditions: temperature, humidity, and atmospheric pressure;

[0059] 2) Check and implement safety procedures: Before charging the test equipment, the test area must be safe and personnel must be evacuated; before personnel re-enter the test area, the capacitor bank of the impulse voltage generator must be grounded;

[0060] 3) Select the initial electrode and complete the test configuration;

[0061] 4) Calibrate impulse voltage generators and measuring instruments;

[0062] 5) Perform impulse discharge on the model and check the photos taken immediately after discharge to ensure that the attachment point of the arc on the model can be clearly identified;

[0063] 6) Apply a set of discharge tests (usually 10 times) to the model;

[0064] 6. Test records and data analysis

[0065] 1) Record the test environment temperature, humidity and atmospheric pressure;

[0066] 2) Record the test times, polarity, discharge voltage, and waveform number;

[0067] 3) Record photos and descriptions of each test arrangement;

[0068] 4) Photos and description of each discharge test;

[0069] 5) Fill in the test operators and witnesses;

[0070] 6) Records of any deviation from the test procedures;

[0071] 7) Analyze the coordinates of each lightning attachment point and count the lightning attachment positions on the model.

[0072] 7. Test result output

[0073] For the ship model attachment position number, see Figure 4 , the serial numbers and corresponding device names are shown in the following table:

[0074]

[0075] Ten discharge tests were conducted at a distance of 1.5m, 2m and 1m between the high-voltage flat electrode and the highest point of the ship model. The typical discharge voltage waveform recorded by the oscilloscope was shown in Figure 1. Figure 5 The leader attachment points of the discharge test are all the highest points on the ship surface, that is, the tip of the lightning rod, indicating that when an upward lightning caused by a ship occurs, the upward leader will be triggered by the ship's lightning rod, and the lightning rod can form an effective direct lightning protection for the entire ship.

[0076] Embodiment 2: This embodiment provides a method for predicting the lightning attachment point caused by a ship, which mainly includes:

[0077] S1, simulation of lightning strikes caused by ships. According to the electrical geometry model, the relationship between the strike distance and the current peak is determined. A flat plate electrode is used to simulate the lightning strike caused by a ship, and a ship scale model is used to carry out the lightning attachment test. The ship lightning protection adopts a strike distance of 30m, and the distance between the high-voltage flat plate electrode and the highest point on the surface of the ship model is determined to be h = 1.5m.

[0078] S2, make the test piece. The test piece is a scaled-down model of the original ship's external structure. A full metal ship model is made of metal plates, and the model scale ratio is 1 / 20. A 1mm thick metal plate is used to simulate the seawater equivalent plane.

[0079] S3, test arrangement. Design the test wiring and arrangement scheme for simulating the lightning leader test caused by ships. The high-voltage electrode is connected to the high-voltage end of the impulse voltage generator. The ship model is placed on a grounded metal plate simulating the seawater equivalent plane. The return line of the impulse voltage generator is connected to the grounded metal plate. The output voltage of the impulse voltage generator is sent to the oscilloscope through a coaxial cable after a voltage divider for measurement.

[0080] S4, test waveform. Use an operating impulse voltage waveform with a rise time of 50 to 250μs. The amplitude of the test waveform is determined by the breakdown of the test piece or the flashover sliding over the test piece. Apply a 50% breakdown voltage of 1.2 times the gap to ensure that the gap can be broken down each time the test is performed.

[0081] S5, determine the test steps. Design the test steps and complete the simulation test.

[0082] S6, Test record and data analysis. Record the test data and conduct statistical analysis to obtain the location and possibility of lightning attachment or breakdown in various areas of the ship when the ship is struck by lightning.

[0083] Furthermore, all parts involved in this application that are not described in detail are the same as the prior art or are implemented using the prior art.

[0084] In summary:

[0085] The present invention proposes a method for predicting lightning attachment points caused by a ship. By conducting a lightning attachment test on a scaled model of a ship caused by lightning strikes, the areas and positions where equipment such as the ship's deck, small mast, antenna, bow anchor light, and stern light are attached or broken down by lightning can be obtained, thereby accurately predicting the lightning attachment probability of the deck equipment. At the same time, the lightning attachment areas caused by lightning strikes on ships are divided according to the test results, which can provide support for lightning protection of equipment and components in each lightning zone of the ship.

[0086] It will be easily understood by those skilled in the art that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for predicting the attachment point of lightning caused by a ship, characterized in that: The steps include: S1, ship-induced lightning strike simulation: a flat plate electrode of preset size is used to simulate the lightning strike caused by a ship; S2, making test pieces: using conductive metal materials to make a scaled model of a ship, and using a metal plate of preset thickness to simulate the seawater equivalent plane; S3, test arrangement: an impulse voltage generator is connected to the flat electrode to generate a simulated lightning strike, a digital storage oscilloscope is used to record the discharge polarity, voltage amplitude and waveform, and an optical camera is used to record the discharge arc path and attachment point; S4, test waveform: the amplitude of the test waveform is determined according to whether the gap between the test piece and the flat electrode is broken down or flashed over the test piece; S5, determining the test steps: performing impact discharge on the scaled model of the ship according to the preset test steps to complete the simulation test; S6, Test records and data analysis: record the test data and conduct statistical analysis to obtain the locations where the lightning is attached or penetrated by the ship's equipment and components when the ship is struck by lightning, as well as the corresponding probability of lightning attachment at each location.

2. A method for predicting the attachment point of lightning caused by a ship according to claim 1, characterized in that: The ship lightning protection adopts a striking distance of 30m, and the length and width of the flat plate electrode are 13m and 3m respectively.

3. A method for predicting the lightning attachment point caused by a ship according to claim 2, characterized in that: The scaling ratio of the scaled-down model of the ship is 1 / 20, and the distance between the flat electrode and the highest point on the surface of the scaled-down model of the ship is 1.5 m.

4. The method for predicting the lightning attachment point caused by a ship according to claim 1, characterized in that: The high voltage end of the impulse voltage generator is connected to the flat electrode, the scaled model of the ship is placed on a grounded metal plate simulating a seawater equivalent plane, and the ground end of the impulse voltage generator is directly connected to the grounded metal plate.

5. A method for predicting the attachment point of lightning caused by a ship according to claim 4, characterized in that: The output voltage of the impulse voltage generator is sent to an oscilloscope through a coaxial cable after passing through a voltage divider to record the discharge polarity, voltage amplitude and waveform of the flat electrode.

6. A method for predicting the lightning attachment point caused by a ship according to claim 4, characterized in that: Specifically, a plurality of optical cameras are provided to record the positions of attachment points on the model at different angles.

7. The method for predicting the lightning attachment point caused by a ship according to claim 1, characterized in that: The impulse voltage of the impulse voltage generator specifically adopts an impulse voltage waveform with a rise time of 50 to 250 μs to simulate a lightning strike caused by a ship.

8. The method for predicting the lightning attachment point caused by a ship according to claim 1, characterized in that: The test steps include: S51, measuring test environmental conditions: the environmental conditions include temperature, humidity, and atmospheric pressure; S52, check the test equipment and perform safety procedures: before charging the test equipment, personnel must be evacuated, and before personnel re-enter the test area, the capacitor bank of the impulse voltage generator must be grounded; S53, selecting a flat electrode of a preset size to complete the layout of the test equipment; S54, Calibration of impulse voltage generators and measuring instruments; S55, performing an impact discharge on the model, and immediately checking the photos taken by the optical camera after the discharge to ensure that the attachment point of the arc on the model can be clearly identified in the photos; S56, performing a preset number of discharge tests on the model.

9. The method for predicting the lightning attachment point caused by a ship according to claim 1, characterized in that: The recorded test data includes: S61, record the temperature, humidity and atmospheric pressure data of the test environment; S62, recording the test number, polarity of the plate electrode, discharge voltage, and waveform number; S63, record photos and descriptions of each discharge test; S64, fill in the test operators and witnesses; S65, count and analyze the coordinates of each lightning attachment point to obtain the probability of the ship's equipment and components being struck by lightning under the natural lightning leader.

10. A method for predicting the attachment point of lightning caused by a ship according to claim 8, characterized in that: When the distance between the flat plate electrode and the highest point on the surface of the scaled ship model is 1.5 m, 2 m and 1 m, the test steps are respectively carried out, and the test results are compared and analyzed.

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