Multi-path lightning stroke current monitoring circuit and device

Abstract

The utility model discloses a multipath lightning stroke current monitoring circuit and device, the monitoring circuit comprises at least one sampling circuit and a single-chip microcomputer, one end of each sampling circuit is externally connected with a Rogowski coil mutual inductor, and the other end of each sampling circuit is connected with the single-chip microcomputer through an A / D converter; the sampling circuit is used for receiving a differential voltage signal output by the Rogowski coil mutual inductor for collecting lightning current, performing sampling, secondary filtering and integral reduction on the differential voltage signal, and outputting a final sampling signal; wherein the sampling circuit comprises an acquisition circuit, a first-stage filter circuit, a voltage following circuit, an integrating circuit and a second-stage filter circuit which are connected in sequence. According to the utility model, multi-path lightning stroke current monitoring can be realized, monitoring objects are more, and installation is convenient and flexible.

Description

Technical Field

[0001] The utility model relates to the technical field of lightning current monitoring, and particularly relates to a multi-channel lightning current monitoring circuit and device. 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 various power grid equipment. Lightning contains powerful and uncertain energy. It can not only damage various outdoor cables and electrical equipment of railways, but also may induce more serious consequences such as fires and explosions, causing problems to human life and property safety.

[0003] The lightning current spectrum is the main basis for studying lightning protection. The lightning current has a large intensity and a short action time, up to about 100 kA at most. The shorter the front time of the lightning current wave, the richer the high-order harmonics, but the energy is mainly concentrated in the low-frequency part. The lightning current waveforms specified in the IEC standard and relevant national standards are mainly 8 / 20 us and 10 / 350 us. Taking 8 / 20 us as an example, the waveform is as Figure 1 shown. The main feature is that when lightning occurs, the current rapidly increases to the maximum value and then gradually decreases to 0. The duration of the whole waveform is generally less than 2 ms. Figure 1 It is the IEC standard test lightning current waveform (8 / 20 us).

[0004] The characteristics of the lightning current are a large current dynamic range, between several hundred A and 100 kA, which is similar to the monitoring of traditional pulsed large currents. Currently, the commonly used pulsed large current test methods mainly include the shunt method, the optical method, the Hall sensor method, and the Rogowski coil method.

[0005] However, for the Rogowski coil lightning current transformer: it can monitor the lightning current and convert it into a low-level voltage signal, but an external circuit is required to process and analyze the data. For the lightning current monitoring device: it monitors the lightning current through a lightning arrester, mainly obtaining the number of lightning strikes and the magnitude of the lightning current, and cannot obtain data such as the front time and half-peak time. At the same time, it can only monitor one-way lightning current, and the filtering effect in one-way sampling is not good, and the original lightning current waveform cannot be accurately restored, etc.

[0006] In view of this, this application is specifically proposed. Content of the Utility Model

[0007] The technical problem to be solved by the present utility model is that the existing lightning current monitoring device can only monitor one-way lightning current, and the filtering effect in one-way sampling is not good, and the original lightning current waveform cannot be accurately restored, etc. The purpose of the present utility model is to provide a multi-way lightning current monitoring circuit and device, which convert the lightning current into a signal that can be sampled by a single-chip microcomputer through a Rogowski coil current transformer and a sampling circuit, and adopt secondary filtering in the sampling circuit to improve the filtering effect; and combine an integration circuit to restore the original lightning current waveform, etc., and can economically realize the monitoring of multi-way lightning current, helping the operation and maintenance personnel to timely detect possible lightning hazards.

[0008] The present utility model is realized through the following technical solutions:

[0009] In the first aspect, the present utility model provides a multi-way lightning current monitoring circuit, which includes at least one sampling circuit and a single-chip microcomputer. One end of each sampling circuit is externally connected to a Rogowski coil current transformer, and the other end of each sampling circuit is connected to the single-chip microcomputer through an A / D converter;

[0010] The sampling circuit is used to receive the differential voltage signal output by the Rogowski coil current transformer for collecting the lightning current, and output the final sampling signal after sampling, secondary filtering and integration restoration;

[0011] Among them, the sampling circuit includes a collection circuit, a first-stage filtering circuit, a voltage follower circuit, an integration circuit and a second-stage filtering circuit connected in sequence.

[0012] As a further preference, the collection circuit includes a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, a first inductor L1, a second inductor L2, a first capacitor C1 and a second capacitor C2;

[0013] One end of the first resistor R1 is connected to the positive pole U1+ of the differential voltage signal output by the Rogowski coil current transformer, the other end of the first resistor R1 is connected to the second resistor R2, the second resistor R2 is connected to the third resistor R3, the third resistor R3 is connected to the fourth resistor R4, and the fourth resistor R4 is connected to the negative pole U1- of the differential voltage signal output by the Rogowski coil current transformer;

[0014] The third resistor R3 is also connected to the first inductor L1, the first inductor L1 is connected to the first capacitor C1, and the first capacitor C1 is grounded;

[0015] The negative pole U1- of the differential voltage signal is also connected to the second inductor L2, the second inductor L2 is connected to the second capacitor C2, and the second capacitor C2 is grounded;

[0016] The second inductor L2 is also connected to the reference voltage VREF to prevent the input differential voltage signal from falling below the lower limit.

[0017] In the design of the above acquisition circuit, the differential voltage signal U1 output by the Rogowski coil current transformer is divided by a series of resistors (the first resistor R1, the second resistor R2, the third resistor R3, and the fourth resistor R4). Since the input voltage U1 may be negative, a reference voltage VREF is added to one end of the second inductor L2 to prevent the voltage from dropping below the lower limit, and the input voltage U1n of the next stage is obtained, thereby ensuring the sampling accuracy.

[0018] As a further optimization, the first-stage filtering circuit includes a fifth resistor R5 and a third capacitor C3. One end of the fifth resistor R5 is connected to the output end of the acquisition circuit, the other end of the fifth resistor R5 is connected to the third capacitor C3, and the third capacitor C3 is grounded.

[0019] In the design of the above first-stage filtering circuit, the first-stage filtering circuit is used to perform the first filtering on the sampling signal output by the acquisition circuit, filter out high-frequency interference signals, and obtain the voltage U1nf after the first-stage filtering.

[0020] As a further optimization, the voltage follower circuit includes a sixth resistor R6, a first operational amplifier U1A, and a seventh resistor R7;

[0021] One end of the sixth resistor R6 is connected to the output end of the first-stage filtering circuit, the other end of the sixth resistor R6 is connected to the non-inverting input terminal of the first operational amplifier U1A, the inverting input terminal of the first operational amplifier U1A is connected to the output terminal of the first operational amplifier U1A through the seventh resistor R7, the positive power supply terminal of the first operational amplifier U1A is connected to the power supply VDD, and the negative power supply terminal of the first operational amplifier U1A is grounded.

[0022] In the design of the above voltage follower circuit, the sixth resistor R6, the first operational amplifier U1A, and the seventh resistor R7 are integrated. The output voltage U1NF of the voltage follower circuit is the same as the voltage U1nf after the first-stage filtering, but it can reduce the input impedance of the next-stage circuit.

[0023] As a further optimization, the integration circuit includes a second operational amplifier U1B, an eighth resistor R8, a ninth resistor R9, a tenth resistor R10, a twelfth resistor R12, and a fifth capacitor C5;

[0024] One end of the eighth resistor R8 is connected to the output end of the voltage follower circuit, the other end of the eighth resistor R8 is connected to the tenth resistor R10, the tenth resistor R10 is connected to the inverting input terminal of the second operational amplifier U1B, and the non-inverting input terminal of the second operational amplifier U1B is connected to the ninth resistor R9; the output terminal of the second operational amplifier U1B is connected to one end of the twelfth resistor R12, and the other end of the twelfth resistor R12 is connected to the common terminal of the eighth resistor R8 and the tenth resistor R10; the fifth capacitor C5 is connected in parallel with the twelfth resistor R12.

[0025] In the design of the above integration circuit, the output voltage U1NF of the voltage follower circuit restores the lightning current waveform after integration. At this time, the voltage U1o is opposite in phase to the lightning current i, and the waveform parameters are the same.

[0026] As a further optimization, the second-stage filtering circuit includes an eleventh resistor R11. One end of the eleventh resistor R11 is connected to the output end of the integration circuit, and the other end of the eleventh resistor R11 is connected to the single-chip microcomputer.

[0027] In the design of the above second-stage filtering circuit, the second-stage filtering circuit is used to perform a second filtering on the voltage signal restored by the integration circuit to filter out high-frequency interference signals and obtain the voltage U1O after the second filtering.

[0028] As a further optimization, the single-chip microcomputer is used to receive the final sampling signal and output data related to the lightning current waveform.

[0029] As a further optimization, the model of the single-chip microcomputer is STM32H723VGT.

[0030] As a further optimization, the monitoring circuit further includes a power supply, and the power supply is connected to both the sampling circuit and the single-chip microcomputer.

[0031] In a second aspect, the present utility model further provides a multi-channel lightning current monitoring device, which includes: a Rogowski coil current transformer and a multi-channel lightning current monitoring circuit; the Rogowski coil current transformer is connected to a multi-channel lightning current monitoring circuit;

[0032] The Rogowski coil current transformer is installed on the cable and is used to convert the lightning current signal in the cable into a differential voltage signal and output it to the monitoring circuit;

[0033] The monitoring circuit is used to receive the differential voltage signal, perform sampling, secondary filtering and integration restoration on the differential voltage signal, and output data related to the lightning current waveform.

[0034] Compared with the prior art, the present utility model has the following advantages and beneficial effects:

[0035] 1. For the multi-channel lightning current monitoring circuit and device of the present utility model, the lightning current is converted into a signal that can be sampled by the single-chip microcomputer through the Rogowski coil current transformer and the sampling circuit, and secondary filtering is adopted in the sampling circuit to improve the filtering effect; combined with the integration circuit to restore the original lightning current waveform, etc., it can economically realize the monitoring of multi-channel lightning current and help the operation and maintenance personnel to timely check for possible lightning hazards.

[0036] 2. For the multi-channel lightning current monitoring circuit and device of the present utility model, the present utility model has more monitoring objects, and is convenient and flexible to install; it can effectively provide data such as the number of lightning currents, time, energy, effective value and waveform. Description of the Drawings

[0037] The drawings described herein are used to provide a further understanding of the embodiments of the present utility model, form a part of this application, and do not limit the embodiments of the present utility model. In the drawings:

[0038] Figure 1 is the IEC standard test lightning current waveform (8 / 20 μs);

[0039] Figure 2 is the actual lightning current waveform (positive current);

[0040] Figure 3 is the actual lightning current waveform (negative current);

[0041] Figure 4 is a schematic diagram of two-channel sampling in a multi-channel lightning current monitoring circuit of the present utility model;

[0042] Figure 5 is a schematic diagram of the sampling circuit in a multi-channel lightning current monitoring circuit of the present utility model;

[0043] Figure 6 is a schematic diagram of the structure of a multi-channel lightning current monitoring device of the present utility model. Detailed Embodiments

[0044] In the following, the term "comprising" or "may comprise" that can be used in various embodiments of the present utility model indicates the presence of the functions, operations, or elements of the present utility model, and does not limit the addition of one or more functions, operations, or elements. In addition, as used in various embodiments of the present utility model, the terms "comprising", "having", and their cognates are only intended to indicate specific features, numbers, steps, operations, elements, components, or combinations of the foregoing items, and should not be construed as precluding the existence or addition of one or more other features, numbers, steps, operations, elements, components, or combinations of the foregoing items first.

[0045] In various embodiments of the present utility model, the expression "or" or "at least one of A or / and B" includes any combination or all combinations of the recited words. For example, the expression "A or B" or "at least one of A or / and B" may include A, may include B, or may include both A and B.

[0046] The expressions (such as "first", "second", etc.) used in various embodiments of the present utility model may modify various components in the various embodiments, but do not limit the corresponding components. For example, the above expressions do not limit the order and / or importance of the components. The above expressions are only used for the purpose of distinguishing one component from other components. For example, the first user device and the second user device indicate different user devices, although both are user devices. For example, without departing from the scope of the various embodiments of the present utility model, the first component may be referred to as the second component, and similarly, the second component may also be referred to as the first component.

[0047] It should be noted that: if it is described that one component is "connected" to another component, the first component may be directly connected to the second component, and a third component may be "connected" between the first component and the second component. Conversely, when one component is "directly connected" to another component, it can be understood that there is no third component between the first component and the second component.

[0048] The terms used in various embodiments of the present utility model are only for the purpose of describing specific embodiments and are not intended to limit the various embodiments of the present utility model. As used herein, the singular form is intended to also include the plural form, unless the context clearly indicates otherwise. Unless otherwise defined, all terms (including technical terms and scientific terms) used herein have the same meaning as commonly understood by those of ordinary skill in the art to which the various embodiments of the present utility model belong. The terms (such as those defined in a general-use dictionary) will be interpreted as having the same meaning as the contextual meaning in the relevant technical field and will not be interpreted as having an idealized meaning or an overly formal meaning, unless clearly defined in the various embodiments of the present utility model.

[0049] To make the purpose, technical solutions and advantages of the present utility model clearer and more understandable, the present utility model will be further described in detail below in conjunction with embodiments and drawings. The illustrative embodiments and descriptions of the present utility model are only used to explain the present utility model and do not limit the present utility model.

[0050] As Figure 1 shown, 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. Figure 1 It only shows the positive current and the first zero-crossing. While the actual lightning current waveform has both positive and negative values, and there are multiple oscillatory zero-crossings before it completely drops to 0, as Figure 2 、 Figure 3 shown.

[0051] Considering that the lightning strike current has a rich spectrum, changes rapidly over time, and the DC component accounts for a very small proportion, the lightning strike current can be converted into a differential voltage signal through a Rogowski coil. After the differential voltage signal is input into this monitoring circuit, it first undergoes resistor voltage division to convert the high voltage into a low voltage signal. The low voltage signal is restored to the original waveform shape through an integration circuit composed of operational amplifiers, and finally input into the AD port of the single-chip microcomputer for sampling; the single-chip microcomputer processes the finally sampled signal and outputs the lightning strike current waveform and various parameters.

[0052] Embodiment 1

[0053] As Figure 4 shown, a multi-channel lightning strike current monitoring circuit of the present utility model includes at least one sampling circuit and a single-chip microcomputer. One end of each sampling circuit is externally connected to a Rogowski coil current transformer, and the other end of each sampling circuit is connected to the single-chip microcomputer through an A / D converter;

[0054] The sampling circuit is used to receive the differential voltage signal output by the Rogowski coil current transformer for collecting the lightning current, and after sampling, secondary filtering and integration restoration, it outputs the final sampling signal;

[0055] Among them, as Figure 5 shown, the sampling circuit includes a collection circuit, a first-stage filtering circuit, a voltage follower circuit, an integration circuit and a second-stage filtering circuit connected in sequence.

[0056] The monitoring circuit further includes a power supply, and the power supply is connected to both the sampling circuit and the single-chip microcomputer.

[0057] Specifically, the monitoring circuit can simultaneously sample two lightning strike current signals; as Figure 4 shown.

[0058] In this embodiment, the collection circuit includes a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, a first inductor L1, a second inductor L2, a first capacitor C1 and a second capacitor C2;

[0059] One end of the first resistor R1 is connected to the positive pole U1+ of the differential voltage signal output by the Rogowski coil current transformer, the other end of the first resistor R1 is connected to the second resistor R2, the second resistor R2 is connected to the third resistor R3, the third resistor R3 is connected to the fourth resistor R4, and the fourth resistor R4 is connected to the negative pole U1- of the differential voltage signal output by the Rogowski coil current transformer;

[0060] The third resistor R3 is also connected to the first inductor L1, the first inductor L1 is connected to the first capacitor C1, and the first capacitor C1 is grounded;

[0061] The negative pole U1- of the differential voltage signal is also connected to the second inductor L2, the second inductor L2 is connected to the second capacitor C2, and the second capacitor C2 is grounded;

[0062] The second inductor L2 is also connected to the reference voltage VREF to prevent the differential voltage signal input from going below the lower limit.

[0063] For the design of the above acquisition circuit, the differential voltage signal U1 output by the Rogowski coil current transformer is divided by series resistors (the first resistor R1, the second resistor R2, the third resistor R3, the fourth resistor R4). Since the input voltage U1 may be negative, the reference voltage VREF is added at one end of the second inductor L2 to prevent the voltage from going below the lower limit, and the input voltage U1n of the next stage is obtained, thereby ensuring the sampling accuracy.

[0064] In this embodiment, the first-stage filtering circuit includes a fifth resistor R5 and a third capacitor C3. One end of the fifth resistor R5 is connected to the first inductor L1, the other end of the fifth resistor R5 is connected to the third capacitor C3, and the third capacitor C3 is grounded.

[0065] For the design of the above first-stage filtering circuit, the first-stage filtering circuit is used to perform the first filtering on the sampling signal output by the acquisition circuit to filter out high-frequency interference signals and obtain the voltage U1nf after the first-stage filtering.

[0066] In this embodiment, the voltage follower circuit includes a sixth resistor R6, a first operational amplifier U1A, and a seventh resistor R7;

[0067] One end of the sixth resistor R6 is connected to the fifth resistor R5, the other end of the sixth resistor R6 is connected to the non-inverting input terminal of the first operational amplifier U1A, the inverting input terminal of the first operational amplifier U1A is connected to the output terminal of the first operational amplifier U1A through the seventh resistor R7, the positive power supply terminal of the first operational amplifier U1A is connected to the power supply VDD, and the negative power supply terminal of the first operational amplifier U1A is grounded.

[0068] For the design of the above voltage follower circuit, the sixth resistor R6, the first operational amplifier U1A, and the seventh resistor R7 are integrated. The output voltage U1NF of the voltage follower circuit is the same as the voltage U1nf after the first-stage filtering, but the input impedance of the next-stage circuit can be reduced.

[0069] In this embodiment, the integration circuit includes a second operational amplifier U1B, an eighth resistor R8, a ninth resistor R9, a tenth resistor R10, a twelfth resistor R12, and a fifth capacitor C5;

[0070] One end of the eighth resistor R8 is connected to the output terminal of the first operational amplifier U1A, the other end of the eighth resistor R8 is connected to the tenth resistor R10, the tenth resistor R10 is connected to the inverting input terminal of the second operational amplifier U1B, and the non-inverting input terminal of the second operational amplifier U1B is connected to the ninth resistor R9; the output terminal of the second operational amplifier U1B is connected to one end of the twelfth resistor R12, and the other end of the twelfth resistor R12 is connected to the common terminal of the eighth resistor R8 and the tenth resistor R10; the fifth capacitor C5 is connected in parallel with the twelfth resistor R12.

[0071] In the above design of the integration circuit, the output voltage U1NF of the voltage follower circuit restores the lightning current waveform after integration. At this time, the voltage U1o is opposite in phase to the lightning current i, and the waveform parameters are the same.

[0072] In this embodiment, the second-stage filtering circuit includes an eleventh resistor R11. One end of the eleventh resistor R11 is connected to the output terminal of the second operational amplifier U1B, and the other end of the eleventh resistor R11 is connected to the single-chip microcomputer.

[0073] In the above design of the second-stage filtering circuit, the second-stage filtering circuit is used to perform a second filtering on the voltage signal restored by the integration circuit to filter out high-frequency interference signals and obtain the voltage U1O after the second filtering.

[0074] In this embodiment, the single-chip microcomputer is used to receive the final sampling signal and output data related to the lightning current waveform. Specifically, the model of the single-chip microcomputer is STM32H723VGT.

[0075] The first differential voltage signal U1 is connected to the 15th pin of the single-chip microcomputer U3 after passing through the sampling circuit, and the second differential voltage signal U2 is connected to the 23rd pin of the single-chip microcomputer U3 after passing through the sampling circuit.

[0076] U1 is the differential voltage signal after the lightning current is converted by the Rogowski coil, and there is a differential relationship with the lightning current. After the voltage signal passes through the sampling circuit voltage dividing circuit, a more appropriate input voltage U1n is obtained at both ends of the fourth resistor R4. U1n passes through the follower composed of the first operational amplifier to obtain U1N with the same amplitude to reduce the input impedance. U1N passes through the integration circuit composed of the second operational amplifier to restore the lightning current waveform to obtain UO. The single-chip microcomputer processes the sampled UO signal and outputs the lightning current waveform and various parameters.

[0077] Embodiment 2

[0078] As Figure 6As shown in the figure, the difference between this embodiment and Embodiment 1 is that this embodiment further provides a multi-channel lightning current monitoring device, which includes: a Rogowski coil current transformer and a multi-channel lightning current monitoring circuit of Embodiment 1; the Rogowski coil current transformer is connected to the multi-channel lightning current monitoring circuit of Embodiment 1;

[0079] The Rogowski coil current transformer is installed on the cable and is used to convert the lightning current signal in the cable into a differential voltage signal and output it to the monitoring circuit;

[0080] The monitoring circuit is used to receive the differential voltage signal, sample, secondarily filter and integrate and restore the differential voltage signal, and output data related to the lightning current waveform.

[0081] Specifically, the relationship between the lightning current i collected by the Rogowski coil current transformer and the output voltage u is as follows: This conversion relationship is common knowledge in the art and will not be elaborated here.

[0082] Specifically, the voltage U1O after the second filtering is converted by an AD converter and then input into the single-chip microcomputer, and the single-chip microcomputer outputs data such as the peak value, effective value, wavefront time, half-peak value time, and waveform of the lightning current.

[0083] The device of the present utility model can realize the monitoring of multi-channel lightning current, with more monitoring objects and convenient and flexible installation.

[0084] The specific embodiments described above have further elaborated on the purpose, technical solutions and beneficial effects of the present utility model. It should be understood that the above are only specific embodiments of the present utility model and are not used to limit the protection scope of the present utility model. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present utility model shall be included in the protection scope of the present utility model.

Claims

1. A multi-channel lightning current monitoring circuit, characterized in that: The monitoring circuit comprises at least one sampling circuit and a single-chip microcomputer, one end of each sampling circuit is externally connected to a Rogowski coil mutual inductor, and the other end of each sampling circuit is connected to the single-chip microcomputer via an A / D converter; The sampling circuit is used to receive the differential voltage signal output by the Rogowski coil mutual inductor when collecting lightning current, sample, filter and integrate the differential voltage signal, and output a final sampling signal; The sampling circuit includes a collection circuit, a first-stage filtering circuit, a voltage follower circuit, an integration circuit and a second-stage filtering circuit which are connected in sequence.

2. A multi-path lightning current monitoring circuit according to claim 1, characterized in that: The acquisition circuit includes a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, a first inductor L1, a second inductor L2, a first capacitor C1 and a second capacitor C2; One end of the first resistor R1 is connected to the positive electrode U1+ of the differential voltage signal output by the Rogowski coil mutual inductor, the other end of the first resistor R1 is connected to the second resistor R2, the second resistor R2 is connected to the third resistor R3, the third resistor R3 is connected to the fourth resistor R4, and the fourth resistor R4 is connected to the negative electrode U1- of the differential voltage signal output by the Rogowski coil mutual inductor; The third resistor R3 is also connected to the first inductor L1, the first inductor L1 is connected to the first capacitor C1, and the first capacitor C1 is grounded; The differential voltage signal negative electrode U1- is also connected to the second inductor L2, the second inductor L2 is connected to the second capacitor C2, and the second capacitor C2 is grounded; The second inductor L2 is also connected to a reference voltage VREF to prevent the input differential voltage signal from exceeding a lower limit.

3. A multi-path lightning current monitoring circuit according to claim 1, characterized in that: The first-stage filtering circuit includes a fifth resistor R5 and a third capacitor C3. One end of the fifth resistor R5 is connected to the output end of the acquisition circuit, and the other end of the fifth resistor R5 is connected to the third capacitor C3. The third capacitor C3 is grounded.

4. A multi-path lightning current monitoring circuit according to claim 1, characterized in that: The voltage follower circuit includes a sixth resistor R6, a first operational amplifier U1A and a seventh resistor R7; One end of the sixth resistor R6 is connected to the output end of the first-stage filter circuit, and the other end of the sixth resistor R6 is connected to the non-inverting input end of the first operational amplifier U1A. The inverting input end of the first operational amplifier U1A is connected to the output end of the first operational amplifier U1A through the seventh resistor R7. The positive power supply end of the first operational amplifier U1A is connected to the power supply VDD, and the negative power supply end of the first operational amplifier U1A is grounded.

5. A multi-path lightning current monitoring circuit according to claim 1, characterized in that: The integration circuit includes a second operational amplifier U1B, an eighth resistor R8, a ninth resistor R9, a tenth resistor R10, a twelfth resistor R12 and a fifth capacitor C5; One end of the eighth resistor R8 is connected to the output end of the voltage follower circuit, the other end of the eighth resistor R8 is connected to the tenth resistor R10, the tenth resistor R10 is connected to the inverting input end of the second operational amplifier U1B, and the non-inverting input end of the second operational amplifier U1B is connected to the ninth resistor R9; the output end of the second operational amplifier U1B is connected to one end of the twelfth resistor R12, and the other end of the twelfth resistor R12 is connected to the common end of the eighth resistor R8 and the tenth resistor R10; the fifth capacitor C5 is connected in parallel with the twelfth resistor R12.

6. A multi-path lightning current monitoring circuit according to claim 1, characterized in that: The second-stage filtering circuit includes an eleventh resistor R11 , one end of the eleventh resistor R11 is connected to the output end of the integration circuit, and the other end of the eleventh resistor R11 is connected to the single-chip microcomputer.

7. A multi-path lightning current monitoring circuit according to claim 1, characterized in that: The single chip microcomputer is used to receive the final sampling signal and output data related to the lightning current waveform.

8. A multi-path lightning current monitoring circuit according to claim 7, characterized in that: The model of the single chip microcomputer is STM32H723VGT.

9. A multi-path lightning current monitoring circuit according to any one of claims 1 to 8, characterized in that: The monitoring circuit also includes a power supply, which is connected to the sampling circuit and the single-chip microcomputer.

10. A multi-channel lightning current monitoring device, characterized in that: The monitoring device comprises: a Rogowski coil mutual inductor and a multi-path lightning current monitoring circuit as claimed in any one of claims 1 to 9; the Rogowski coil mutual inductor is connected to a multi-path lightning current monitoring circuit as claimed in any one of claims 1 to 9; The Rogowski coil mutual inductor is installed on the cable and is used to convert the lightning current signal in the cable into a differential voltage signal and output it to the monitoring circuit; The monitoring circuit is used to receive the differential voltage signal, sample, perform secondary filtering and integrate the differential voltage signal, and output data related to the lightning current waveform.

Images