A lightning strike current sampling device and its calculation method

Abstract

The present invention discloses a lightning strike current sampling device and its calculation method, which includes a high-speed bidirectional zero-crossing single-shot trigger circuit. The high-speed bidirectional zero-crossing single-shot trigger circuit includes a high-speed bidirectional comparison unit, a level setting unit, and a single-shot trigger unit. The effective capture and locking of the starting point of the lightning strike current are achieved through the high-speed bidirectional comparison unit, the level setting unit, and the single-shot trigger unit, avoiding mis-triggering caused by multiple trigger problems. The present invention effectively filters out multiple zero-crossing flips of the lightning strike current waveform through the high-speed bidirectional zero-crossing single-shot trigger circuit, and only responds to the first zero-crossing, ensuring that the sampling will not be mis-triggered; at the same time, it will not miss sampling the lightning strike current, reducing waveform loss. Moreover, by adopting the principle of hardware high-speed bidirectional zero-crossing single-shot trigger to capture the starting point of the lightning strike current, and through the combination of software and hardware for lightning strike current acquisition and calculation, the problem that existing lightning strike monitoring products can only achieve single-channel lightning strike current monitoring, resulting in poor lightning protection effect, is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of lightning monitoring, and particularly relates to a lightning strike current sampling device and a calculation method thereof. Background Art

[0002] Lightning is the most common natural phenomenon in people's lives, and lightning disasters are also one of the main factors affecting the safe operation of power grids. Lightning contains powerful and uncertain energy. It can not only damage power transmission and distribution lines, electrical equipment, etc., but also may induce more serious consequences such as fires and explosions, causing problems to human life and property safety. With the rapid development of information technology, a large amount of data involving security and privacy is stored in electronic devices, and the impact of lightning strikes on these devices is becoming more and more obvious.

[0003] When a lightning strike occurs, the lightning strike current will flow through the struck device and its lines to the ground. At the same time, the rapidly changing current will generate a strong magnetic field around it, which will then be coupled to adjacent lines, endangering the safe operation of related signal devices. Outdoor overhead cables are the main source of lightning strikes. Therefore, lightning arresters are usually used for lightning protection before the cables enter the indoor computer room equipment. In fact, in multi-thunderstorm areas, the working state of lightning arresters cannot be effectively monitored, and there is only a status switch quantity indication. That is, when the lightning arrester fails, a switch quantity status is given to indicate that the lightning arrester needs to be replaced.

[0004] However, there are the following problems in the current lightning protection design.

[0005] 1. The lightning energy is powerful and uncertain, and the selection of lightning arrester specifications lacks a scientific basis, resulting in a high failure rate of lightning arresters.

[0006] 2. The residual voltage of the lightning arrester increases with the increase in the number of impacts, and the protection performance is a gradually decreasing process. This process cannot be effectively monitored, and only relying on the switch quantity status cannot determine the best time to replace the lightning arrester. Under high residual voltage, the equipment will have the risk of being damaged by a large lightning strike current.

[0007] 3. Due to the strong magnetic field coupling effect, different degrees of lightning strike current will be induced on adjacent cables. Currently, there are no economical and effective products for monitoring lightning strike currents of multiple cables, which is not conducive to the refined development of lightning strike current monitoring systems. Some devices increase the design cost due to overprotection, while some devices frequently fail due to insufficient protection.

[0008] With the development of information technology, lightning strike current monitoring devices have emerged on the market in recent years. However, due to the characteristics of large flow range, high speed, wide frequency spectrum, large amount of data, and time-consuming starting point capture algorithm of lightning current, sampling and calculation of it require a processor with high computing power. Due to cost pressure, in fact, most products can only achieve single-channel lightning strike current monitoring. Summary of the Invention

[0009] Aiming at the problems proposed in the background technology, the purpose of the present invention is to provide a lightning strike current sampling device and its calculation method. By adopting the principle of high-speed bidirectional zero-crossing single-shot triggering of hardware to capture the starting point of the lightning strike current, and through the combination of software and hardware for lightning strike current acquisition and calculation, it solves the problem that existing lightning strike monitoring products can only achieve single-channel lightning strike current monitoring, resulting in poor lightning protection effect.

[0010] The present invention is realized through the following technical solutions:

[0011] The first aspect of the present invention provides a lightning strike current sampling device, including

[0012] A high-speed bidirectional zero-crossing single-shot triggering circuit;

[0013] The high-speed bidirectional zero-crossing single-shot triggering circuit includes a high-speed bidirectional comparison unit, a level setting unit, and a single-shot triggering unit;

[0014] The input end of the high-speed bidirectional comparison unit is connected to the level setting unit, the output end of the high-speed bidirectional comparison unit is connected to the input end of the single-shot triggering unit, and the output end of the single-shot triggering unit is connected to the chip U2A;

[0015] The single-shot triggering unit is used to provide a trigger signal to the CPU and receive a low-level reset signal sent by the CPU.

[0016] In the above technical solution, the level setting unit is used to divide the reference voltage VREF. The level setting unit inputs the divided reference voltage VREF into the high-speed bidirectional comparison unit. The high-speed bidirectional comparison unit simultaneously receives the voltage signal VIN after the lightning strike current passes through the Rogowski coil and the conditioning circuit and the divided reference voltage VREF, and compares them and transmits the comparison signal to the single-shot triggering unit. The single-shot triggering circuit generates a falling-edge trigger signal to trigger the CPU for AD sampling. Therefore, the single-shot triggering circuit can effectively filter out multiple zero-crossing flips of the lightning strike current waveform and only respond to the first zero-crossing to ensure that the sampling will not be mis-triggered. When the CPU receives the trigger signal, it can automatically respond to capture the lightning strike current waveform. After the sampling is completed, before the next sampling, the CPU sends a low-level reset signal to the single-shot triggering unit, and the high-speed bidirectional zero-crossing single-shot triggering circuit will respond to the capture of the next lightning strike current. The data processing time of the CPU can be completed within dozens of milliseconds, so as to ensure the effective capture of multiple channels.

[0017] In a possible embodiment, the high-speed comparison unit includes a comparator U1A and a comparator U1B. The 2-pin of the comparator U1A is used to receive the voltage signal VIN, and the 5-pin of the comparator U1B is used to receive the voltage signal VIN.

[0018] In a possible embodiment, the voltage signal VIN is the voltage signal after the lightning strike current passes through the Rogowski coil and the conditioning circuit.

[0019] In a possible embodiment, the level setting unit includes a resistor R1, a resistor R2, and a resistor R3. One end of the resistor R1 is connected to the reference voltage VREF, and the other end is connected to the 3-pin of the comparator U1A; one end of the resistor R3 is connected to the 6-pin of the comparator U1B, and the other end is grounded; both ends of the resistor R2 are respectively connected to the 3-pin of the comparator U1A and the 6-pin of the comparator U1B.

[0020] In a possible embodiment, the single-shot trigger circuit includes a resistor R4, a resistor R5, a resistor R6, a resistor R7, a resistor R8, a triode Q1, a triode Q2, and a chip U2A;

[0021] Wherein, the emitter of the triode Q1 is respectively connected to the 1-pin of the comparator U1A, the resistor R4, and the resistor R7, and the base of the triode Q1 is connected to the resistor R6; the emitter of the triode Q1 is respectively connected to the 7-pin of the comparator U1B, the resistor R5, and the resistor R6, the base of the triode Q2 is connected to the resistor R7, the chip U2A is respectively connected to the collector of the triode Q1 and the collector of the triode Q2, and the resistor R8 is connected between the chip U2A and the power supply VCC.

[0022] In a possible embodiment, the chip U2A includes an SD port, a CD port, and a Q port. The SD port is connected to the resistor R8, the SD port is respectively connected to the collector of the triode Q1 and the collector of the triode Q2, the CD port is used to receive a low-level reset signal, and the Q port is used to send a trigger signal to the CPU.

[0023] In a possible embodiment, the chip U2A further includes a D port, a CLK port, and a GND port, and the D port, the CLK port, and the GND port are all grounded.

[0024] The second aspect of the present invention provides a method for calculating lightning strike current, including:

[0025] Step S1: Sampling using a lightning strike current sampling device to obtain lightning strike current data;

[0026] Step S2: Analyzing the lightning strike current data to obtain the current peak value, the wavefront time, and the half-peak time;

[0027] Step S3: Calculate the waveform effective value by using the root mean square algorithm for the current peak value, the wavefront time, and the half-peak time, and count the lightning strike times according to the trigger times of the lightning current sampling device.

[0028] In a possible embodiment, the sampling frequency of the sampling is not less than 2 MHz, and the fixed sampling duration of the sampling is 2 ms.

[0029] In a possible embodiment, before the step S2, it further includes: removing the all-zero data at the tail of the lightning current data.

[0030] Compared with the prior art, the present application has the following advantages and beneficial effects:

[0031] 1. Effectively filter out multiple zero-crossing flips of the lightning current waveform, only respond to the first zero-crossing, and ensure that the sampling will not be mis-triggered;

[0032] 2. The high-speed bidirectional zero-crossing single trigger circuit will not miss sampling the lightning current, reducing waveform loss;

[0033] 3. Since a bidirectional zero-crossing single trigger circuit is adopted, there is no need to consider the capture algorithm in software, which is greatly simplified. The real-time performance can be guaranteed. The sampling and calculation processes are very simplified, and the entire calculation can be completed within dozens of milliseconds, which can ensure the effective capture of multiple channels and will not miss sampling the lightning current. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the technical solutions of the exemplary embodiments of the present invention, the following will briefly introduce the drawings required in the embodiments. It should be understood that the following drawings only show some embodiments of the present invention, and therefore should not be regarded as limiting the scope. For those of ordinary skill in the art, other related drawings can be obtained based on these drawings without creative efforts. In the drawings:

[0035] Figure 1 It is a schematic diagram of the IEC standard test lightning current waveform;

[0036] Figure 2 It is a schematic diagram of the actual lightning current waveform (positive current);

[0037] Figure 3 It is a schematic diagram of the actual lightning current waveform (negative current);

[0038] Figure 4 It is a schematic diagram of the structure of a high-speed bidirectional zero-crossing single trigger circuit provided by Embodiment 1 of the present invention;

[0039] Figure 5 It is a schematic diagram of the flow of a lightning current calculation method provided by Embodiment 2 of the present invention. Detailed implementation mode

[0040] To make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below with reference to embodiments and drawings. The illustrative implementation modes of the present invention and their descriptions are only used to explain the present invention and are not intended to limit the present invention.

[0041] Embodiment 1

[0042] Figure 4 As shown in the structural schematic diagram of a high-speed bidirectional zero-crossing single trigger circuit provided in Embodiment 1 of the present invention, Figure 4 as shown, a high-speed bidirectional zero-crossing single trigger circuit includes:

[0043] a high-speed bidirectional comparison unit, a level setting unit and a single trigger unit;

[0044] The input end of the high-speed bidirectional comparison unit is connected to the level setting unit, the output end of the high-speed bidirectional comparison unit is connected to the input end of the single trigger unit, and the output end of the single trigger unit is connected to the chip U2A;

[0045] The single trigger unit is used to provide a trigger signal to the CPU and receive a low-level reset signal sent by the CPU.

[0046] It should be noted that Figure 1 The IEC standard test lightning current waveform only shows the main part of the lightning current, basically including more than 90% of the energy of the lightning current. Only the positive current and the first zero-crossing are shown in the figure. The actual lightning current waveform has positive and negative values, and there are multiple oscillatory zero-crossings before it completely drops to 0, as Figure 2 、 Figure 3 shown. From Figure 2 、 Figure 3 it can be seen that the commonly used zero-crossing trigger circuit cannot effectively capture and lock the starting point of the lightning current, and there will be multiple trigger problems, causing false triggers; and because the lightning current has positive and negative directions, the zero-crossing trigger needs to solve the problem of positive and negative currents, that is, it needs to have the window trigger characteristic; in addition, the wavefront time is very short, in the microsecond level, and a high-speed trigger circuit is required to reduce waveform loss.

[0047] Therefore, to effectively capture the lightning strike current waveform, the present invention provides a high-speed bidirectional zero-crossing single-shot trigger circuit, which realizes the effective capture and locking of the starting point of the lightning strike current through a high-speed bidirectional comparison unit, a level setting unit, and a single-shot trigger unit, avoiding mis-triggering caused by multiple trigger problems. Specifically, the level setting unit is used to divide the reference voltage VREF. After dividing the reference voltage VREF, the level setting unit inputs it into the high-speed bidirectional comparison unit. The high-speed bidirectional comparison unit simultaneously receives the voltage signal VIN of the lightning strike current after passing through the Rogowski coil and the conditioning circuit and the divided reference voltage VREF, compares them, and transmits the comparison signal to the single-shot trigger unit. The single-shot trigger circuit generates a falling-edge trigger signal to trigger the CPU to perform AD sampling. Therefore, the single-shot trigger circuit can effectively filter out the multiple zero-crossing flips of the lightning strike current waveform and only respond to the first zero-crossing to ensure that the sampling is not mis-triggered. When the CPU receives the trigger signal, it can automatically respond to capture the lightning strike current waveform. After the sampling is completed, before the next sampling, the CPU sends a low-level reset signal to the single-shot trigger unit, and the high-speed bidirectional zero-crossing single-shot trigger circuit will respond to the capture of the next lightning strike current. Since the data processing time of the CPU can be completed within dozens of milliseconds, it is actually impossible to miss the sampling of the lightning strike current.

[0048] In a possible embodiment, the high-speed comparison unit includes a comparator U1A and a comparator U1B. The 2-pin of the comparator U1A is used to receive the voltage signal VIN, and the 5-pin of the comparator U1B is used to receive the voltage signal VIN.

[0049] In a possible embodiment, the voltage signal VIN is the voltage signal of the lightning strike current after passing through the Rogowski coil and the conditioning circuit.

[0050] It should be noted that the voltage signal VIN is the voltage signal of the lightning strike current after passing through the Rogowski coil and the conditioning circuit, and it is proportional to the magnitude of the lightning strike current.

[0051] In a possible embodiment, the 8-pin of the comparator U1A is connected to the supply voltage.

[0052] In a possible embodiment, the level setting unit includes a resistor R1, a resistor R2, and a resistor R3. One end of the resistor R1 is connected to the reference voltage VREF, and the other end is connected to the 3-pin of the comparator U1A; one end of the resistor R3 is connected to the 6-pin of the comparator U1B, and the other end is grounded; both ends of the resistor R2 are respectively connected to the 3-pin of the comparator U1A and the 6-pin of the comparator U1B.

[0053] It should be noted that VREF is the reference voltage. After being divided by the voltage division unit composed of resistor R1, resistor R2, and resistor R3, appropriate high and low comparison thresholds are obtained across R2, so as to ensure that the starting points of both positive and negative lightning strike currents can be effectively captured.

[0054] In a possible embodiment, the single-shot trigger circuit includes resistor R4, resistor R5, resistor R6, resistor R7, resistor R8, transistor Q1, transistor Q2, and chip U2A;

[0055] Among them, the emitter of transistor Q1 is respectively connected to pin 1 of comparator U1A, resistor R4, and resistor R7, and the base of transistor Q1 is connected to resistor R6; the emitter of transistor Q1 is respectively connected to pin 7 of comparator U1B, resistor R5, and resistor R6, the base of transistor Q2 is connected to resistor R7, chip U2A is respectively connected to the collector of transistor Q1 and the collector of transistor Q2, and resistor R8 is connected between chip U2A and power supply VCC.

[0056] In a possible embodiment, chip U2A includes an SD port, a CD port, and a Q port. The SD port is connected to resistor R8, the SD port is respectively connected to the collector of transistor Q1 and the collector of transistor Q2, the CD port is used to receive a low-level reset signal, and the Q port is used to send a trigger signal to the CPU.

[0057] In a possible embodiment, chip U2A further includes a D port, a CLK port, and a GND port, and the D port, the CLK port, and the GND port are all grounded.

[0058] In a possible embodiment, the middle node of resistor R4 and resistor R5 is grounded.

[0059] In a possible embodiment, resistor R8 is connected to the supply voltage.

[0060] The working principle of a high-speed bidirectional zero-crossing single-shot trigger circuit is as follows:

[0061] The voltage signal VIN is the voltage signal of the lightning strike current after passing through the Rogowski coil and the conditioning circuit, which is proportional to the magnitude of the lightning strike current. The voltage signal is input into the high-speed bidirectional comparison unit composed of comparator U1A and comparator U1B; at the same time, after the reference voltage VREF is divided by the voltage division circuit composed of resistor R1, resistor R2, and resistor R3, appropriate high and low comparison thresholds are obtained across resistor R2 and input into the high-speed bidirectional comparison unit to ensure that the starting points of both positive and negative lightning strike currents can be effectively captured.

[0062] The two-way output after the high-speed two-way comparison unit compares the two is passed through a single-shot circuit composed of resistor R4, resistor R5, resistor R6, resistor R7, resistor R8, triode Q1, triode Q2, and chip U2A, so that SAMPLE_EN generates a falling-edge trigger signal to trigger the CPU to perform AD sampling. This single-shot trigger circuit can effectively filter out the multiple zero-crossing flips of the lightning strike current waveform and only respond to the first zero-crossing to ensure that the sampling will not be accidentally triggered. When the CPU receives the trigger signal, it can automatically respond to capture the lightning strike current waveform. After the sampling is completed, before the next sampling, the CPU sends a low-level reset signal on SAMPLE_RST, and the circuit will respond to the capture of the next lightning strike current. Since the data processing time of the CPU can be completed within dozens of milliseconds, it is actually impossible to miss the sampling of the lightning strike current.

[0063] Embodiment 2

[0064] Figure 5 It is a schematic flowchart of a lightning strike current calculation method provided by Embodiment 2 of the present invention, as Figure 5 shown, a lightning strike current calculation method includes:

[0065] Step S1: Sampling is performed using a lightning strike current sampling device provided in Embodiment 1 to obtain lightning strike current data;

[0066] Step S2: Analyze the lightning strike current data to obtain the current peak value, wavefront time, and half-peak time;

[0067] Step S3: Calculate the waveform effective value by using the root mean square algorithm for the current peak value, the wavefront time, and the half-peak time, and count the number of lightning strikes according to the trigger times of the lightning strike current sampling device.

[0068] Among them, the lightning strike current: a natural phenomenon, which refers to the surge impact current that is discharged to the ground through the struck object when a lightning strike occurs.

[0069] Wavefront time: It is defined as 1.25 times the time interval between two points corresponding to 10% peak value and 90% peak value during the rising process of the lightning strike current.

[0070] Half-peak time: It is defined as the time interval from the virtual starting point of the lightning strike current to the time when the current drops to half of the peak value.

[0071] Lightning strike current monitoring sensor: An electrically isolated sensor that can monitor parameters such as the peak value, effective value, wavefront time, half-peak time, impact duration, and impact times of the lightning strike current.

[0072] It should be noted that, first, the software is configured to start AD sampling at the falling edge of SAMPLE_EN, then analyze the data to obtain the current peak value, wavefront time, and half-peak time. Finally, the root mean square algorithm is used to calculate the effective value of the waveform and count the number of lightning strikes, etc. After the calculation is completed, the CPU makes SAMPLE_RST output a low-level signal to reset the bidirectional zero-crossing single-shot trigger circuit to start capturing the next lightning strike current.

[0073] In the present invention, due to the adoption of the bidirectional zero-crossing single-shot trigger circuit, there is no need to consider the capture algorithm in software, which is greatly simplified, and the real-time performance can be guaranteed. The sampling and calculation processes are very simplified, and the entire calculation can be completed within dozens of milliseconds, which can ensure the effective capture of multiple channels and will not miss the sampling of lightning strike current.

[0074] In a possible embodiment, the sampling frequency of the sampling is not less than 2 MHz, and the fixed sampling duration of the sampling is 2 ms.

[0075] It should be noted that the sampling frequency is not less than 2 MHz, and the fixed sampling duration is 2 ms (i.e., 4000 samples are sampled).

[0076] In an alternative embodiment, before the step S2, it further includes: removing the all-zero data at the tail of the lightning strike current data.

[0077] It should be noted that the all-zero data at the tail of the data is removed to determine the actual length of the lightning strike current waveform data.

[0078] It should be emphasized that the current mainstream lightning strike current detection sensors are all single-channel. The reason is that the real-time performance of the lightning strike current start point and end point algorithms needs to be guaranteed, which requires a high CPU and affects multi-channel acquisition. Since in actual sampling, there is also a certain error between the two sampling results under the same input, in order to ensure that the start point is not misjudged, multiple difference calculations and judgments should be performed. And because there are multiple oscillations in the actual waveform, such as Figure 2As shown, some logical reasoning is required. With multiple channels, the algorithm time increases exponentially. These calculations must be completed within the two sampling intervals to determine whether a lightning current has occurred. Sampling cannot be interrupted during this period, otherwise data loss will occur. Since lightning currents only occur briefly, the sampling rate is typically above 2MHz, resulting in a time between sampling points of only 0.5µs. This places significant demands on CPU computing power, significantly increasing costs. Consequently, mainstream products primarily utilize single-channel measurement devices, reducing the number of significant data bits in the sampled values to ensure real-time monitoring and cost control. The typical approach to achieving multi-channel acquisition in this scenario is to use multiple sensors, which inevitably results in increased auxiliary power consumption, increased costs, and larger installation footprint. Furthermore, since the dispersed data must be collected by a host computer before being aggregated and distributed, this compromises real-time data analysis and reduces reliability. While higher-performance CPUs are an option, this comes at a significant cost increase.

[0079] In response to the defects and requirements of current mainstream lightning current detection sensors, the present invention designs a lightning current sampling device and its calculation method. Through a combination of software and hardware, it simplifies the capture of waveform starting points to achieve multi-channel acquisition. A high-speed, bidirectional, zero-crossing, single-shot trigger circuit is designed. When a lightning strike occurs, the CPU triggers AD sampling. The CPU no longer performs real-time, pure software starting point judgment calculations for each AD channel, but easily starts multi-channel AD sampling. After sampling is completed, the multi-channel lightning current waveform is calculated and output according to the designed software algorithm. The present invention effectively reduces the system's requirements for the real-time performance of the algorithm and is applicable to the design of multi-channel lightning current monitoring sensors.

[0080] The specific implementation methods described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation method of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A lightning strike current sampling device, characterized in that, Comprising: A high-speed bidirectional zero-crossing single-shot trigger circuit; The high-speed bidirectional zero-crossing single-shot trigger circuit includes a high-speed bidirectional comparison unit, a level setting unit, and a single-shot trigger unit; The input end of the high-speed bidirectional comparison unit is connected to the level setting unit, the output end of the high-speed bidirectional comparison unit is connected to the input end of the single-shot trigger unit, and the output end of the single-shot trigger unit is connected to chip U2A; The single-shot trigger unit is used to provide a trigger signal to the CPU and receive a low-level reset signal sent by the CPU.

2. The lightning strike current sampling device according to claim 1, characterized in that, The high-speed bidirectional comparison unit includes comparator U1A and comparator U1B. The 2-pin of comparator U1A is used to receive voltage signal VIN, and the 5-pin of comparator U1B is used to receive voltage signal VIN.

3. The lightning strike current sampling device according to claim 2, characterized in that, The voltage signal VIN is the voltage signal after the lightning strike current passes through the Rogowski coil and the conditioning circuit.

4. The lightning strike current sampling device according to claim 2, characterized in that, The level setting unit includes resistor R1, resistor R2, and resistor R3. One end of resistor R1 is connected to reference voltage VREF, and the other end is connected to the 3-pin of comparator U1A; one end of resistor R3 is connected to the 6-pin of comparator U1B, and the other end is grounded; both ends of resistor R2 are respectively connected to the 3-pin of comparator U1A and the 6-pin of comparator U1B.

5. The lightning strike current sampling device according to claim 2, wherein The single-shot trigger unit includes resistor R4, resistor R5, resistor R6, resistor R7, resistor R8, triode Q1, triode Q2, and chip U2A; Wherein, the emitter of triode Q1 is respectively connected to the 1-pin of comparator U1A, resistor R4, and resistor R7, and the base of triode Q1 is connected to resistor R6; the emitter of triode Q1 is respectively connected to the 7-pin of comparator U1B, resistor R5, and resistor R6, the base of triode Q2 is connected to resistor R7, chip U2A is respectively connected to the collectors of triode Q1 and triode Q2, and resistor R8 is connected between chip U2A and power supply VCC.

6. The lightning strike current sampling device according to claim 5, characterized in that, The chip U2A includes an SD port, a CD port, and a port. The SD port is connected to the resistor R8, and the SD port is respectively connected to the collector of the triode Q1 and the collector of the triode Q2. The CD port is used to receive a low-level reset signal, and the port is used to send a trigger signal to the CPU.

7. The lightning strike current sampling device according to claim 6, characterized in that, Chip U2A also includes a D port, a CLK port, and a GND port, and the D port, the CLK port, and the GND port are all grounded.

8. A method for calculating lightning strike current, characterized in that, Comprising: Step S1: Use a lightning strike current sampling device as described in claims 1 to 7 for sampling to obtain lightning strike current data; Step S2: Analyze the lightning strike current data to obtain the current peak value, wavefront time, and half-peak time; Step S3: Use the root mean square algorithm to calculate the current peak value, the wavefront time, and the half-peak time to obtain the waveform effective value, and count the lightning strike times according to the trigger times of the lightning strike current sampling device.

9. A method for calculating lightning strike current according to claim 8, characterized in that, The sampling frequency of the sampling is not less than 2MHz, and the fixed sampling duration of the sampling is 2ms.

10. A method for calculating lightning strike current according to claim 8, characterized in that, Before step S2, it also includes: removing the all-zero data at the tail of the lightning strike current data.

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