Test System for Lightning Stratification Current Characteristics of Forest Combustion Materials and Test and Analysis Methods for Lightning Stratification Current Characteristics

Abstract

This invention discloses a test system for the lightning stratification current characteristics of forest combustibles and a test and analysis method for the lightning stratification current characteristics. The test system includes a lightning pulse current source, a forest combustible sample, a lightning stratification current characteristic clamping mechanism, and a lightning current control and its electrical parameter measurement and analysis unit. By using the test data of the forest combustible stratification current under the action of lightning current and employing data statistical methods, the stratification characteristics of forest combustibles and the correlation between the lightning current shunting characteristics in different strata and factors such as the moisture content of forest combustibles and the electrical parameters of lightning current are finally obtained. This forms a database of lightning stratification current characteristics of forest combustibles simulating different regional characteristics, laying the foundation for multi-physics field modeling and calculation of the smoldering and ignition mechanisms caused by lightning strikes on forest combustibles.

Description

Technical Field

[0001] This invention relates to a test method for the characteristics of forest fires caused by lightning strikes, and particularly to a test system for the lightning stratification current characteristics of forest combustibles, as well as a test and analysis method for the lightning stratification current characteristics. Background Technology

[0002] Based on spatial distribution, combustibles are classified into three categories: forest combustibles, above-ground high-rise forest combustibles, and underground forest combustibles. Among them, forest combustibles, including fallen leaves and undecomposed coarse humus, have the greatest impact on fire risk levels. Based on viability, forest combustibles are classified into living forest combustibles and dead forest combustibles. For living forest combustibles, moisture content is an important indicator for predicting forest fire occurrence, forest fire behavior, energy release, and estimating forest fire risk. Dead forest combustibles are a major cause of forest fires. Studying the distribution of dead forest combustibles on the forest floor is of great significance for fire prevention and forest combustible management.

[0003] Lightning is a multiple, continuous, time-series discharge process. In this process, the first lightning strike plays a crucial role, involving the adhesion process between the lightning strike and forest combustibles. It directly affects the lightning stratification current characteristics of different layers of forest combustibles, and is of great significance to the theoretical research on the smoldering or ignition mechanisms of forest lightning strikes. Existing research on lightning-induced fires mainly relies on predictive models built from historical lightning-induced fire data, predicting the probability and location of lightning-induced fires based on meteorological conditions and forest conditions. However, there are very few reports in the literature on the generation and development of lightning-induced fires, focusing on the physical processes or mechanisms of lightning adhesion to forest combustibles and lightning stratification current. Therefore, the accuracy of existing predictive models for lightning strike warnings is difficult to guarantee. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the present invention aims to provide a test system for the lightning stratification current characteristics of forest combustibles, as well as a test and analysis method for the lightning stratification current characteristics. This system obtains the correlation between the stratification current characteristics of forest combustibles under lightning strikes and the climate environment, the mode of lightning current action, and electrical parameters, laying the foundation for multi-physics field modeling and calculation of the smoldering and ignition mechanisms of forest combustibles caused by lightning strikes.

[0005] This invention is achieved through the following technical solution:

[0006] A test system for lightning stratification current characteristics of forest combustibles includes a lightning pulse current source, a forest combustible sample, a lightning stratification current characteristic clamping mechanism, and a lightning current control and electrical parameter measurement and analysis unit.

[0007] The lightning pulse current source includes a controllable high-voltage DC charging power supply and a lightning pulse current generating unit. The charging voltage of the lightning pulse current generating unit is monitored by a charging voltage monitoring sensor, and the analog quantity of the charging voltage is transmitted to the control unit 31 of the lightning current control and its electrical parameter measurement and analysis unit.

[0008] The forest combustible sample is installed through the clamping mechanism of the lightning stratification current test and electrically connected to the lightning pulse current generating unit.

[0009] The clamping mechanism is a mounting fixture with a high-voltage electrode HV and multiple low-voltage electrodes LV. The high-voltage electrode is an electrode plate with the same size as one end face of the forest combustible. The multiple low-voltage electrodes are strip-shaped electrodes corresponding to the texture of the other end face of the forest combustible. The high-voltage electrode HV is electrically connected to the output high-voltage port of the lightning pulse current generating unit, and the multiple low-voltage electrodes LV are electrically connected to the low-voltage port of the lightning pulse current generating unit respectively.

[0010] The lightning current control and its electrical parameter measurement and analysis unit realizes the control of the lightning stratification current test of forest combustibles and the measurement and analysis of the electrical parameters of lightning pulse current, including a control unit and a lightning pulse current measurement and analysis unit.

[0011] Furthermore, the controllable high-voltage DC charging power supply mainly consists of an electronically controlled voltage regulator T1, a transformer T2, and a voltage multiplier capacitor C. B The system consists of rectifier silicon stacks D1 and D2 and a current-limiting resistor Rc. The lightning pulse current generating unit mainly consists of a pulse energy storage capacitor C, a high-voltage discharge switch G, a waveform forming inductor L, and a resistor R. These components are electrically connected in series, and the tested forest combustible sample and its connecting clamps are connected in series in the circuit of the energy storage capacitor, the high-voltage discharge switch G, the waveform forming inductor, and the resistor.

[0012] Furthermore, the clamping mechanism includes an insulating box with a four-sided structure for placing forest combustible samples. High-voltage electrode plates and multiple low-voltage electrode plates LV1 to LVN are designed on the inner surfaces of opposite sides of the insulating box, where N is the number of layers of the forest combustible texture. Electrical connection terminals with different layers on the side end face of the forest combustible are led out through the multiple low-voltage electrode plates.

[0013] Multiple low-voltage electrodes LV1 to LVN are electrically connected to the low-voltage output port of the lightning pulse current generating unit. Current induction coils L1, L2, ..., LN are used to measure the lightning current of each layer of forest combustibles. The lightning current waveforms Im1, Im2, ..., ImN of the forest combustibles are measured respectively. In the table below, m represents the number of data points of the lightning current.

[0014] Furthermore, the charging voltage monitoring circuit receives the signal transmitted from the charging voltage monitoring sensor, and after processing by the programmable controller and its related control circuits, outputs a control signal to the programmable controller and its related control circuits, thereby controlling the discharge switch of the lightning pulse current generating unit. The programmable controller and its related control circuits are also combined with the industrial control computer of the lightning pulse current measurement and analysis unit to control the connection / disconnection, high voltage rise / fall, and discharge control of the discharge switch G in the charging process of the forest combustible lightning stratification current characteristic test, thereby realizing the automatic control of the forest combustible lightning stratification current characteristic test process.

[0015] Furthermore, the lightning pulse current parameter measurement and analysis unit mainly consists of pulse current sensors 32-1, 32-2, ..., 32-N, a digital oscilloscope, and an industrial control computer 32-4. The pulse current sensors 32-1, 32-2, ..., 32-N, in conjunction with the digital oscilloscope 32-3, measure the lightning stratification current characteristics of different areas of forest combustibles. The industrial control computer processes and analyzes the lightning stratification current signals of different areas of forest combustibles obtained by the digital oscilloscope, thereby obtaining parameters such as the moisture content of forest combustibles, ambient temperature and humidity, and lightning current point electrical parameters, as well as the lightning stratification of forest combustibles and the stratification current characteristics of different strata.

[0016] A test and analysis method for the lightning strike diversion characteristics of standing trees in forests includes the following steps:

[0017] (1) Sample selection and treatment: Select forest combustible samples with typical forest areas and process the samples to obtain multiple forest combustible samples with different humidity and moisture content.

[0018] (2) Select the first forest combustible sample S1 with the highest moisture content for testing; each electrode of the clamping mechanism is electrically connected to the lightning pulse current generating unit, the high voltage electrode HV is in close contact with one end face of the forest combustible sample, and multiple low voltage electrodes LV1 to LVN are in close contact with the different textured sections of the other end face of the forest combustible sample.

[0019] 1) Apply lightning current pulses with different peak values ​​to forest combustibles. The pulse current discharge unit outputs the preset first discharge current point I1, and obtains the stratified current data I11, I12, ..., I1N of the forest combustibles.

[0020] 2) Change the output current of the pulse current discharge unit so that the preset discharge current point changes from I1 to Im, and obtain the corresponding shunt data Im1, Im2, ..., ImN of the standing trees in the forest;

[0021] 3) Analyze the lightning stratified current data of forest combustibles I11, I12, ..., I1N up to Im1, Im2, ..., ImN. If the deviation between two adjacent stratified current data points of forest combustibles is very small under the action of lightning current pulses with no less than 5 amplitude data points, then the two adjacent stratified current data points will be merged.

[0022] 4) Repeat steps 2) to 3) for the lightning current stratification of the combined forest fuels until the lightning current stratification of the forest fuel sample S1 is determined.

[0023] 5) Select the next sample with different moisture content and repeat steps 1) to 4) until all combustible samples with different moisture contents have been tested for lightning stratification, and obtain the lightning stratification of forest combustible samples and the stratification current characteristics of each stratum.

[0024] (3) For forest combustible samples with different temperatures and humidity, repeat the test process in step (2) to obtain lightning current shunting data for each area of ​​the forest combustible samples with different temperatures and humidity.

[0025] (4) Statistical analysis was performed on all forest combustible lightning stratification current test data to obtain the correlation between forest combustible stratification and lightning stratification current intensity with forest combustible sample moisture content, temperature and humidity, and to form a forest combustible lightning stratification current database and characteristic laws.

[0026] This invention focuses on the lightning stratification current characteristics of forest combustibles struck by lightning. It establishes an experimental system for the lightning stratification current characteristics of forest combustibles and proposes an experimental method for the lightning stratification current characteristics of forest combustibles. Through experimental data on the stratification current of forest combustibles under the action of lightning current, and using data statistical methods, it finally obtains the stratification characteristics of forest combustibles and the correlation between the current shunting characteristics of lightning in different strata and factors such as the moisture content of forest combustibles and the electrical parameters of lightning current. This forms a database of lightning stratification current characteristics of forest combustibles simulating different regional characteristics, laying the foundation for multi-physics field modeling and calculation of smoldering and ignition mechanisms caused by lightning strikes on forest combustibles. Attached Figure Description

[0027] Figure 1 This is a structural block diagram of the lightning stratification current characteristic test system of the present invention;

[0028] Figure 2 This is a circuit block diagram of the lightning stratification current characteristic test system of the present invention;

[0029] Figure 3 This invention relates to a clamping mechanism for testing the lightning stratification current characteristics of forest combustibles according to the present invention.

[0030] (a) is a diagram of the multi-layer structure of forest combustibles clamped by the clamping mechanism; (b) is a schematic diagram of the electrodes in the clamping mechanism. Figure 1 (c) is a schematic diagram of the electrodes in the clamping mechanism. Figure 2 ;

[0031] Figure 4 A flowchart for the experimental and analytical methods of lightning stratification current characteristics of forest combustibles. Detailed Implementation

[0032] The present invention will be further described in detail below with reference to specific embodiments. These descriptions are for explanation purposes only and are not intended to limit the scope of the invention.

[0033] join Figure 1 , Figure 2 The test system for lightning stratification current characteristics of forest combustibles of the present invention consists of a lightning pulse current source 1, a forest combustible sample 2, a lightning stratification current characteristic clamping mechanism, and a lightning current control and electrical parameter measurement and analysis unit 3.

[0034] The lightning pulse current source 1 mainly consists of a controllable high-voltage DC charging power supply 1-1 and a lightning pulse current generating unit 1-2. In actual tests, the charging voltage of the controllable high-voltage DC charging power supply 1-1 to the lightning pulse current generating unit 1-2 is monitored online by the charging voltage monitoring sensor 1-3, and the analog charging voltage is transmitted to the control unit 31 of the lightning current control and its electrical parameter measurement and analysis unit 3.

[0035] See Figure 2 The principle circuit of the lightning pulse current source 1 for the lightning stratification current characteristic test of forest combustibles in this invention mainly consists of two parts: a controllable high-voltage DC charging power supply 1-1 and a lightning pulse current generating unit 1-2. Given the extremely high amplitude and high voltage environment during actual lightning strikes, and the unique breakdown characteristics of forest combustibles, the operating voltage of the lightning pulse power supply in this application cannot be too low, at least 100kV or even higher. Therefore, the controllable high-voltage DC charging power supply 1-1 can adopt a conventional rectification and filtering charging method, but it is best to adopt a voltage multiplier charging method to avoid corona discharge during the experiment, which would affect the reliability and stability of the lightning pulse current source.

[0036] The controllable high-voltage DC charging power supply 1-1 mainly consists of an electronically controlled voltage regulator T1, a transformer T2, and a voltage multiplier capacitor C. B The system consists of rectifier silicon stacks D1 and D2 and a current-limiting resistor Rc. The lightning pulse current generating unit 1-2 mainly consists of a pulse energy storage capacitor C, a high-voltage discharge switch G, a waveform forming inductor L, and a resistor R. These components are electrically connected in series, and the tested forest combustible sample and its connecting clamp are connected in series in the circuit of the energy storage capacitor, the high-voltage discharge switch G, the waveform forming inductor, and the resistor.

[0037] See Figure 3 As shown in (a), forest combustibles constitute a complex multi-layered structure with layers of fallen leaves, humus, leaching, sediment, parent material, and parent rock, each layer exhibiting significant differences in materials and properties. In laboratory simulation studies, theoretical research can construct multi-layered models for numerical calculations, but the simulation results are difficult to verify. In reality, the thickness of forest combustible samples obtainable in experimental studies is generally 300-500 mm, which can simulate the characteristics of combustibles in typical forest areas to a certain extent.

[0038] like Figure 3 In the lightning stratification current test shown in (b) and (c), the clamping mechanism is to install forest combustibles on a mounting fixture structure with a high-voltage electrode HV and multiple low-voltage electrodes LV. The high-voltage electrode HV is electrically connected to the output high-voltage port of the lightning pulse current generating unit 1-2, and the multiple low-voltage electrodes LV are electrically connected to the low-voltage port (or return electrode) of the lightning pulse current generating unit 1-2 respectively.

[0039] The clamping mechanism for forest combustibles is a four-sided insulating box, which holds the forest combustible sample 2. High-voltage electrode plates and multiple low-voltage electrode plates LV1 to LVN are designed on the inner surfaces of opposite sides of the insulating box, where N represents the number of layers in the forest combustible's texture. The multiple low-voltage electrode plates are used to lead out electrical connection terminals to different layers on the side end face of the forest combustible.

[0040] Multiple low-voltage electrodes LV1 to LVN, which are in close contact with the side end face of forest combustibles, are electrically connected to the low-voltage output port of the lightning pulse current generating unit. Current induction coils L1, L2, ..., LN are used to measure the lightning current of each layer of forest combustibles. The lightning current layer current waveforms Im1, Im2, ..., ImN of the forest combustibles are measured respectively. In the table below, m (≥5) represents the number of data points of the lightning current.

[0041] The high-voltage electrode is an electrode plate of the same size as the end face of the forest fuel. Multiple low-voltage electrodes are strip-shaped electrodes corresponding to the texture of the forest fuel end face. The size of the electrodes changes with the lightning stratification of the forest fuel. The high-voltage electrode is connected to the high-voltage terminal of the lightning pulse current generating unit, and each low-voltage electrode is individually connected to the low-voltage terminal of the pulse current discharge unit. A current induction coil is inserted in the connecting lines between the multiple low-voltage electrodes and the pulse discharge unit to measure the lightning current stratification current of the forest fuel. By injecting lightning current pulses of different peak values ​​into the forest fuel, lightning stratification current data of the forest fuel under the action of different peak value lightning current pulses can be obtained.

[0042] The function of the lightning current control and its electrical parameter measurement and analysis unit 3 is to control the lightning stratification current test of forest combustibles and to measure and analyze the electrical parameters of the lightning pulse current. It mainly consists of a control unit 31 and a lightning pulse current measurement and analysis unit 32. The control unit 31 mainly consists of a charging voltage monitoring circuit 31-1 and a programmable logic controller (PLC) and its related control circuits 31-2. The charging voltage monitoring circuit 31-1 of the control unit 31 receives the signal transmitted from the charging voltage monitoring sensor 1-3, and after processing by the PLC and its related control circuits 31-2, it can output a control signal to the PLC and its related control circuits 31-2, thereby controlling the discharge switch of the lightning pulse current generating unit 1-2. Furthermore, the PLC and its related control circuits 31-2, in conjunction with the industrial control computer 32-4 of the lightning pulse current measurement and analysis unit 32, control the connection / disconnection of the charging process, the rise / fall of the high voltage, and the discharge control of the discharge switch G in the lightning stratification current characteristic test of forest combustibles, realizing the automatic control of the forest combustibles lightning stratification current characteristic test process.

[0043] The lightning pulse current parameter measurement and analysis unit 32 mainly consists of pulse current sensors 32-1, 32-2, ..., 32-N, a digital oscilloscope 32-3, and an industrial control computer 32-4. The pulse current sensors 32-1, 32-2, ..., 32-N, in conjunction with the digital oscilloscope 32-3, measure the lightning stratification current characteristics of different areas of forest combustibles. The industrial control computer 32-4 processes and analyzes the lightning stratification current signals of different areas of forest combustibles obtained by the digital oscilloscope 32-3, thereby obtaining parameters including forest combustible moisture content, ambient temperature and humidity, and lightning current point electrical parameters, as well as the lightning stratification of forest combustibles and the stratification current characteristics of different strata.

[0044] To improve the reliability and dependability of lightning stratification current characteristic data for forest combustibles under repeated lightning strikes, the lightning pulse discharge current source should ensure that the amplitude of the pulse current flowing through the forest combustibles is not too large, ideally on the order of several kA. Otherwise, ablation may occur, making it impossible to obtain stratification current characteristic data for at least m (≥5) data points. If the number of forest combustible layers is greater than 4, two oscilloscopes or a multi-channel data acquisition system can be used in conjunction with an industrial computer for data acquisition, recording, and analysis.

[0045] See Figure 4 Experimental and analytical methods for the stratified current characteristics of forest combustibles under lightning strikes. The specific experimental and analytical procedures are as follows:

[0046] 1) Sample selection and treatment: Select forest combustible samples from typical forest areas and treat the samples, including humidity and moisture content, to simulate the actual environment of different plants under different seasons and climatic conditions.

[0047] Prepare forest combustible samples with different moisture contents, at least 5 samples with different moisture contents (denoted as S1 to S5), and the samples can be selected from typical forest areas with different climatic characteristics (such as the Greater Khingan Mountains, Liangzhou, etc.).

[0048] 2) Select / reselect the first forest fuel sample S1 with the lowest moisture content for the test;

[0049] 3) Install the forest combustibles in the clamping mechanism and connect the low-voltage electrodes and high-voltage electrodes of the clamping mechanism to the output terminal of the lightning pulse current generating unit.

[0050] 4) Apply lightning current pulses of different peak values ​​to forest combustibles and measure lightning stratification current data under different peak lightning currents using multiple current sensors.

[0051] Select m (≥5) discharge current (or discharge voltage) points, and achieve the output of the preset discharge current peak value through the discharge voltage of pulse current discharge unit 1-2.

[0052] 5) Change the charging voltage of the energy storage capacitor of the controllable high-voltage DC charging power supply 1-1 to the pulse current discharge unit 1-2. When the control unit 31 detects that the charging voltage of the energy storage capacitor is greater than or equal to the preset discharge voltage U1, the control unit 31 outputs a discharge pulse to the controllable high-voltage discharge switch of the pulse current discharge unit 1-2. The pulse current discharge unit 1-2 outputs the preset first discharge current point I1, corresponding to the stratification current data I11, I12, ..., I1N of the forest combustibles. Similarly, change the charging voltage of the energy storage capacitor of the controllable high-voltage DC charging power supply 1-1 to the pulse current discharge unit 1-2 until the pulse current discharge unit 1-2 outputs the preset first discharge current point Im, corresponding to the stratification current data Im1, Im2, ..., ImN of the forest combustibles.

[0053] 6) Analyze the lightning stratified current data of forest combustibles I11, I12, ..., I1N up to Im1, Im2, ..., ImN. If the deviation between two adjacent stratified current data points of forest combustibles is very small (e.g., less than 5%) under the action of lightning current pulses with no less than 5 amplitude data points, then the two adjacent strata can be merged.

[0054] 7) Repeat steps 2) to 5) for the lightning current stratification of the combined forest combustibles until the lightning current stratification of the forest combustible sample S1 is determined.

[0055] 8) Select the next sample with different moisture content and repeat steps 3) to 7) until all combustible samples with different moisture contents have been tested for lightning stratification, and obtain the lightning stratification of forest combustible samples and the stratification current characteristics of each stratum.

[0056] 9) For the lightning stratification current characteristics of forest combustible samples under different temperature and humidity conditions, the test method is the same as that for samples with different moisture contents. The test process can be repeated to obtain the results.

[0057] 10) Statistical analysis was conducted on all forest combustible lightning stratification current test data to obtain the correlation between forest combustible stratification and lightning stratification current intensity with factors such as forest combustible sample moisture content and climate environment, forming a forest combustible lightning stratification current database and characteristic laws, laying the foundation for the establishment of lightning strike or model and lightning fire prediction.

[0058] 11) Using multi-factor regression and other methods, analyze the lightning stratification current of forest combustibles in the lightning stratification current database to form an evaluation method for the characteristics of lightning stratification current of forest combustibles.

Claims

1. A test system for the lightning stratification current characteristics of forest combustibles, characterized in that: It includes a lightning pulse current source (1), a forest combustible sample (2), a lightning stratified current characteristic clamping mechanism, and a lightning current control and electrical parameter measurement and analysis unit (3); The lightning pulse current source (1) includes a controllable high voltage DC charging power supply (1-1) and a lightning pulse current generating unit (1-2). The charging voltage of the controllable high voltage DC charging power supply (1-1) to the lightning pulse current generating unit (1-2) is monitored by a charging voltage monitoring sensor (1-3), and the analog quantity of the charging voltage is transmitted to the control unit (31) of the lightning current control and its electrical parameter measurement and analysis unit (3). The forest combustible sample (2) is installed through the clamping mechanism of the lightning stratification current test and electrically connected to the lightning pulse current generating unit (1-2); The clamping mechanism is a mounting fixture with a high-voltage electrode HV and multiple low-voltage electrodes LV. The high-voltage electrode is an electrode plate with the same size as one end face of the forest combustible. The multiple low-voltage electrodes are strip-shaped electrodes corresponding to the texture of the other end face of the forest combustible. The high-voltage electrode HV is electrically connected to the output high-voltage port of the lightning pulse current generating unit (1-2), and the multiple low-voltage electrodes LV are electrically connected to the low-voltage port of the lightning pulse current generating unit (1-2) respectively. The lightning current control and its electrical parameter measurement and analysis unit (3) realizes the control of the lightning stratification current test of forest combustibles and the measurement and analysis of the electrical parameters of lightning pulse current, including the control unit (31) and the lightning pulse current measurement and analysis unit (32).

2. The test system for lightning stratification current characteristics of forest combustibles according to claim 1, characterized in that: The controllable high-voltage DC charging power supply (1-1) mainly consists of an electronically controlled voltage regulator T1, a transformer T2, and a voltage multiplier capacitor C. B The rectifier silicon stacks D1 and D2 and the current-limiting resistor Rc are composed of a rectifier silicon stack D1 and D2 and a current-limiting resistor Rc. The lightning pulse current generating unit (1-2) is mainly composed of a pulse energy storage capacitor C, a high-voltage discharge switch G, a waveform forming inductor L and a resistor R. They are electrically connected in series, and the test forest combustible sample and its connecting clamp are connected in series in the circuit of the energy storage capacitor, the high-voltage discharge switch G, the waveform forming inductor and the resistor.

3. The test system for lightning stratification current characteristics of forest combustibles according to claim 1, characterized in that: The clamping mechanism includes an insulating box with a four-sided structure for placing the forest combustible sample (2). High voltage electrode plates and multiple low voltage electrode plates LV1 to LVN are designed on the inner sides of the opposite sides of the insulating box, where N is the number of layers of the forest combustible texture. Electrical connection terminals with different layers on the side end face of the forest combustible are led out through the multiple low voltage electrode plates. Multiple low-voltage electrodes LV1 to LVN are electrically connected to the low-voltage output port of the lightning pulse current generating unit. Current induction coils L1, L2, ..., LN are used to measure the lightning current of each layer of forest combustibles. The lightning current layer current waveforms Im1, Im2, ..., ImN of the forest combustibles are measured respectively, where m represents the number of lightning current data points.

4. The test system for lightning stratification current characteristics of forest combustibles according to claim 1, characterized in that: The charging voltage monitoring circuit (31-1) receives the signal transmitted from the charging voltage monitoring sensor (1-3), and after processing by the programmable controller and its related control circuit (31-2), outputs a control signal to the programmable controller and its related control circuit (31-2) to control the discharge switch of the lightning pulse current generating unit (1-2). The programmable controller and its related control circuit (31-2) are also combined with the industrial control computer (32-4) of the lightning pulse current measurement and analysis unit (32) to control the connection / disconnection, high voltage rise / fall and discharge control of the charging process of the forest combustible lightning stratification current characteristic test, thereby realizing the automatic control of the forest combustible lightning stratification current characteristic test process.

5. The test system for lightning stratification current characteristics of forest combustibles according to claim 1, characterized in that: The lightning pulse current parameter measurement and analysis unit (32) mainly consists of pulse current sensors (32-1), (32-2), ..., (32-N), a digital oscilloscope (32-3), and an industrial control computer (32-4). The pulse current sensors (32-1), (32-2), ..., (32-N) and the digital oscilloscope (32-3) are combined to measure the lightning stratification current characteristics of different areas of forest combustibles with different humidity and water content. The industrial control computer (32-4) processes and analyzes the lightning stratification current signals of different areas of forest combustibles measured by the digital oscilloscope (32-3), thereby obtaining the correlation between forest combustible water content, ambient temperature and humidity, and lightning current point electrical parameters, as well as the stratification current characteristics of different strata.

6. A test and analysis method for the lightning strike diversion characteristics of standing trees in forests based on the test system of claim 3, characterized in that... Includes the following steps: (1) Sample selection and treatment: Select forest combustible samples with typical forest areas and process the samples to obtain multiple forest combustible samples with different humidity and moisture content. (2) Select the first forest combustible sample S1 with the highest moisture content for testing; each electrode of the clamping mechanism is electrically connected to the lightning pulse current generating unit, the high voltage electrode HV is in close contact with one end face of the forest combustible sample, and multiple low voltage electrodes LV1 to LVN are in close contact with the different textured sections of the other end face of the forest combustible sample. 1) Apply lightning current pulses with different peak values ​​to forest combustibles. The pulse current discharge unit (1-2) outputs the preset first discharge current point I1, and obtains the stratified current data I11, I12, ..., I1N of the forest combustibles. 2) Change the output current of the pulse current discharge unit (1-2) so that the preset discharge current point changes from I1 to Im, and obtain the corresponding shunt data Im1, Im2, ..., ImN of the standing trees in the forest; 3) Analyze the lightning stratified current data of forest combustibles I11, I12, ..., I1N up to Im1, Im2, ..., ImN. If the deviation between two adjacent stratified current data points of forest combustibles is very small under the action of lightning current pulses with no less than 5 amplitude data points, then the two adjacent stratified current data points will be merged. 4) Repeat steps 2) to 3) for the lightning current stratification of the combined forest fuels until the lightning current stratification of the forest fuel sample S1 is determined. 5) Select the next sample with different moisture content and repeat steps 1) to 4) until all combustible samples with different moisture contents have been tested for lightning stratification, and obtain the lightning stratification of forest combustible samples and the stratification current characteristics of each stratum. (3) For forest combustible samples with different temperatures and humidity, repeat the test process in step (2) to obtain lightning current shunting data for each area of ​​the forest combustible samples with different temperatures and humidity. (4) Statistical analysis was performed on all forest combustible lightning stratification current test data to obtain the correlation between forest combustible stratification and lightning stratification current intensity with forest combustible sample moisture content, temperature and humidity, and to form a forest combustible lightning stratification current database and characteristic laws.

Images