Dual-channel multiple lightning stroke current waveform monitoring system

Abstract

The invention relates to the technical field of lightning current monitoring, and discloses a dual-channel multiple lightning current waveform monitoring system, which comprises two acquisition coils, two groups of signal amplification circuits, an FPGA sampling module and an MCU master control module, the two acquisition coils are respectively connected to the FPGA sampling module through two groups of signal amplification circuits; and the two groups of amplifying circuits have different amplification factors to configure large and small range channels. And the FPGA performs parallel high-frequency A / D sampling on the two paths of amplified signals and transmits data to the MCU. And the MCU compares and analyzes the two paths of data: if the waveform data of the channel with the smaller measuring range is not subjected to saturation distortion, the waveform data of the channel with the smaller measuring range is selected as a monitoring result, and otherwise, the waveform data of the channel with the larger measuring range is selected as a monitoring result. According to the invention, accurate identification of multiple lightning stroke current pulses possibly generated in the same lightning stroke event can be realized, and high-efficiency and high-precision acquisition of currents with different intensities can be realized.

Description

Technical Field

[0001] This invention relates to the field of lightning current monitoring technology, specifically a dual-channel, multi-channel lightning current waveform monitoring system. Background Technology

[0002] Lightning disasters are among the most serious natural disasters, posing not only casualties and fire hazards to people and buildings, but also significant threats to power systems, communication facilities, aerospace, and other fields. Effective protection against lightning disasters necessitates the effective monitoring and research of lightning strikes and the currents they generate. In particular, the accurate measurement of parameters for multiple lightning strikes (including multiple return strokes) is crucial for studying the physical characteristics of lightning, assessing the lightning threat to equipment, and improving lightning protection measures.

[0003] Most existing lightning current monitoring technologies can achieve complete measurement of basic parameters such as waveform, peak value, and polarity of the current generated during a lightning strike, and can be combined with IoT technology to achieve server platform monitoring. However, in addition to these, lightning current waveform monitoring still faces the following major technical bottlenecks: (1) Incomplete measurement of short-interval multiple current pulses: When a lightning strike occurs, the interval between multiple return strokes may be in the millisecond range. Currently, most devices can only accurately measure a single current pulse. For multiple short-interval current pulses, the triggering mechanism or data processing capability of some devices is insufficient to support the identification of continuous current pulses. Often, only the first pulse or the pulse with the largest amplitude can be measured. Therefore, it is usually wrongly judged as a single independent lightning strike event, losing key timing information, which leads to the inability to accurately measure the number of return strokes and the interval. (2) The dynamic range of lightning current is large, and the measurement range and accuracy are insufficient: The current amplitude range generated by lightning strike is extremely wide, usually ranging from hundreds of amperes to hundreds of thousands of amperes. The single lightning current sampling channel in the current mainstream technology cannot simultaneously meet the high measurement accuracy under small current and the unsaturated distortion under large current. (3) Data integrity issues: Some systems use relays to switch ranges, which can cause waveform data loss during the switching process, making it impossible to fully record the complete process of a lightning strike and the possible multiple return strikes; (4) Problems of insufficient time accuracy and missing location information: Traditional lightning current monitoring usually lacks high-precision time reference and location function, making it difficult to trace the data after the fact, and when lightning strikes multiple times, it is impossible to accurately measure the time interval between each strike.

[0004] (5) Sampling rate and reliable transmission issues: The waveform of lightning current changes extremely rapidly, requiring the acquisition system to have a very high sampling rate and a high A / D conversion accuracy and speed. Under this requirement, it is also necessary to take into account the real-time transmission of a large amount of high-speed data to ensure that the lightning current data measured multiple times at short intervals is not lost. Summary of the Invention

[0005] To address the technical problems existing in the prior art, this invention provides a dual-channel multiple lightning strike current waveform monitoring system, which can accurately identify multiple lightning strike current pulses that may be generated in the same lightning strike event, and efficiently and accurately collect currents of different intensities.

[0006] To achieve the above objectives, the present invention provides the following technical solution: This invention discloses a dual-channel, multi-channel lightning strike current waveform monitoring system, comprising: two acquisition coils, two sets of signal amplification circuits, an FPGA sampling module, and an MCU main control module. The two acquisition coils are connected to the FPGA sampling module via the two sets of signal amplification circuits. The two sets of signal amplification circuits are used to filter and enhance the current signals generated by the same lightning strike event in the two acquisition coils, generating two analog signals. The two sets of signal amplification circuits have different amplification factors to configure channels with different ranges. The FPGA sampling module is connected to the MCU main control module via a data bus and is used to perform high-frequency A / D sampling of the two analog signals, and transmit the sampled and converted waveform data to the MCU main control module. The MCU main control module is used to compare and analyze the two waveform data corresponding to the same lightning strike event: if the waveform data of the channel with the smaller range does not experience saturation distortion, the waveform data of the channel with the smaller range is selected as the monitoring result; otherwise, the waveform data of the channel with the larger range is selected as the monitoring result.

[0007] As a further improvement to the above scheme, each signal amplification circuit includes a differential amplification circuit for suppressing common-mode interference signals and an anti-aliasing filter circuit for filtering out high-frequency interference noise; wherein, the two signal amplification circuits use amplification resistors with different resistance values.

[0008] As a further improvement to the above solution, the FPGA sampling module integrates a digital triggering unit, which is used to generate a trigger signal based on preset waveform characteristic parameters. The waveform characteristic parameters include the current change rate and amplitude threshold. When the current waveform and amplitude of the analog signal exceed the corresponding threshold, sampling is triggered and converted into data, which is then transmitted to the MCU main control module through a serial communication interface.

[0009] As a further improvement to the above scheme, the FPGA sampling module is also equipped with a multiple lightning strike identification and separation mechanism. This mechanism is used to trigger the sampling process after the rate of change and amplitude of the induced current reach a threshold. The sampling circuit is re-ready within a millisecond-level set time after completing one analog-to-digital conversion in order to capture and separate multiple return current pulses with millisecond-level intervals in the same lightning strike event.

[0010] As a further improvement to the above solution, the system also includes a GPS positioning module; the GPS positioning module is used to provide time and positioning information for real-time recording of the time and location of the lightning current pulse. As a further improvement to the above solution, the system also includes a local storage module; the local storage module includes an EEPROM storage unit and a FLASH storage unit, both of which are connected to the MCU main control module in the form of a data bus, and are used to store device parameters and lightning current waveform data.

[0011] As a further improvement to the above solution, the MCU main control module is also used to enable the local RTC clock and use the time information provided by the GPS positioning module to calibrate the local RTC clock in real time. When a lightning strike occurs, the MCU main control module uses the calibrated local RTC to record the millisecond-level timestamps of each return strike, and encapsulates the waveform data, timestamps and positioning information into a data frame, and controls the local storage unit to write the data frame into the FLASH storage unit for backup.

[0012] As a further improvement to the above solution, the system also includes a 4G communication module; the 4G communication module is used to establish a connection with a remote server via the TCP protocol and maintain the connection via heartbeat packets; the MCU main control module is also used to transmit the encapsulated data frames to the server via the 4G communication module.

[0013] As a further improvement to the above solution, the system also includes a power supply circuit; the power supply circuit is electrically connected to the MCU main control module, FPGA sampling module, GPS positioning module, local storage module and 4G communication module, and is used to provide operating voltage for each module.

[0014] As a further improvement to the above scheme, the acquisition coil is a Rogowski coil.

[0015] Compared with the prior art, the beneficial effects of the present invention are: This invention discloses a dual-channel multiple lightning strike current waveform monitoring system. Leveraging the parallel processing capabilities and intelligent triggering logic of an FPGA, it can quickly recover to a ready state after each sampling trigger, ensuring that subsequent strikes are captured without omission, thus achieving complete monitoring of multiple lightning strikes. The dual-range parallel sampling design resolves the main contradiction between insufficient accuracy in small current measurements and susceptibility to distortion in large current measurements, expanding the range of lightning current monitoring. The dual channels always operate in parallel, eliminating the data loss problem caused by range switching in traditional monitoring systems, enabling continuous monitoring of multiple current pulses. Combined with GPS time and location information, the data can be used for multi-site joint analysis, allowing for precise traceability of event occurrence time and accurate calculation of the time interval between multiple lightning strikes. The FPGA+MCU architecture improves the real-time performance and reliability of multiple lightning strike monitoring, increases sampling accuracy and sampling rate, enhances data transmission reliability, and ensures data security through local storage and remote transmission. Attached Figure Description

[0016] Figure 1 This is a framework diagram of the dual-channel multiple lightning strike current waveform monitoring system in an embodiment of the present invention.

[0017] Figure 2 This is a flowchart illustrating the working principle of the dual-channel multiple lightning current waveform monitoring system in this embodiment of the invention.

[0018] Figure 3 This is a software flowchart of the MCU main control module in an embodiment of the present invention. Detailed Implementation

[0019] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] Please see Figure 1 This embodiment provides a dual-channel multi-lightning current waveform monitoring system, including: two acquisition coils, two sets of signal amplification circuits, an FPGA sampling module and an MCU main control module, and may also include a GPS positioning module, a local storage module, a 4G communication module and a power supply circuit.

[0021] The power supply circuit is electrically connected to the MCU main control module, FPGA sampling module, GPS positioning module, local storage module and 4G communication module to provide operating voltage for each module.

[0022] The outputs of the two acquisition coils are connected to the inputs of two sets of signal amplification circuits, which in turn are connected to the FPGA sampling module. The FPGA module is connected to the MCU main control module via a data bus to transmit the current waveform and various parameters obtained after A / D conversion to the main control module. The GPS module and 4G communication module are also connected to the MCU main control module via a data bus. The local storage module is also connected to the MCU main control module to store current data and time information when a lightning strike occurs.

[0023] The acquisition coil is a Rogowski coil. Two sets of signal amplification circuits are used to filter and enhance the current signals generated by the same lightning strike event in the two acquisition coils, generating two analog signals. The two sets of signal amplification circuits have different amplification factors to configure channels with different ranges.

[0024] In this embodiment, each signal amplification circuit includes a differential amplification circuit with a high common-mode rejection ratio for suppressing common-mode interference signals, and an anti-aliasing filter circuit for filtering out high-frequency interference noise. The two signal amplification circuits employ amplification resistors of different values ​​to control different amplification factors, thereby simultaneously meeting the measurement requirements of two different measurement ranges. The first acquisition path is configured with a high-sensitivity range (e.g., 20A~2kA) for accurately capturing and measuring waveforms such as small-amplitude induced lightning currents and pre-discharge currents. The second acquisition path is configured with a high-range range (e.g., 2kA~200kA) for distortion-free measurement of large-current waveforms such as those from direct lightning strikes.

[0025] The FPGA sampling module, acting as a high-precision A / D sampling conversion module, connects to the MCU main control module via a data bus. It performs high-frequency continuous sampling of two analog signals and transmits the sampled and converted waveform data to the MCU main control module. The FPGA acquisition module can also connect to the MCU main control module via a serial communication interface for transmitting waveform data. In some embodiments, the FPGA sampling module integrates a digital trigger unit. This digital trigger unit generates a trigger signal based on preset waveform characteristic parameters, including the current change rate and amplitude threshold. When the current waveform and amplitude of the analog signal exceed the corresponding thresholds, sampling is triggered, and the data is converted and transmitted to the MCU main control module via the serial communication interface.

[0026] The FPGA sampling module of this invention can be configured for high-sensitivity triggering, and with high-speed A / D conversion, it can significantly reduce resource occupation time and quickly re-ready the sampling circuit. The FPGA sampling module is also equipped with a multiple lightning strike identification and separation mechanism. This mechanism is used to trigger the sampling process after the rate of change and amplitude of the induced current reach a threshold, and re-ready the sampling circuit within a millisecond-level set time after completing one analog-to-digital conversion, so as to capture and separate multiple return current pulses with millisecond-level intervals in the same lightning strike event.

[0027] The GPS positioning module is used to provide time and location information for real-time recording of the time and location of lightning current pulses.

[0028] The local storage module includes an EEPROM storage unit and a FLASH storage unit, both of which are connected to the MCU main control module via a data bus and are used to store device parameters and lightning current waveform data.

[0029] The MCU main control module is used to compare and analyze two waveform data corresponding to the same lightning strike event: if the waveform data of the channel with the smaller range does not have saturation distortion, the waveform data of the channel with the smaller range is selected as the monitoring result; otherwise, the waveform data of the channel with the larger range is selected as the monitoring result.

[0030] In some embodiments, the MCU master module can be configured to perform the following steps: The local RTC clock is enabled, and the time information provided by the GPS positioning module is used to calibrate the local RTC clock in real time. When a lightning strike occurs, the two-channel waveform data transmitted by the FPGA are received and compared, and the data within the optimal range is selected for analysis and processing. The MCU main control module uses the calibrated local RTC to record the millisecond-level timestamps of each return strike, and encapsulates the waveform data, timestamps, and positioning information into a data frame. The local storage unit is controlled to write the data frame into the FLASH storage unit for backup, and the encapsulated data frame is also transmitted to the server through the 4G communication module.

[0031] The MCU main control module of this invention enables a local RTC clock to calibrate the local time in real time according to the GPS time, ensuring that the lightning strike time is recorded accurately after the GPS connection is lost; the local RTC is accurate to the millisecond level, and can accurately record the millisecond-level timestamp of the return strike when the lightning strike occurs, so as to detect the return strike interval and number.

[0032] In some embodiments, the 4G module is connected to the server platform via TCP to transmit waveform data encapsulated by the MCU main control module according to a specific protocol to the TCP server platform for remote monitoring, and is configured to maintain network connection with the server via heartbeat packets.

[0033] Please see Figure 2The figure illustrates the specific working principle flow of the dual-channel multiple lightning strike current waveform monitoring system of the present invention. The working principle and lightning current acquisition process of the present invention are described as follows: First, when lightning strikes and multiple return strikes occur, multiple current pulses are generated. The lightning arrester sequentially leads these current pulses to the down conductor, and the two acquisition coils sequentially sense multiple alternating current signals, which are then transmitted to the two signal amplification circuits. Second, the two signal amplification circuits filter and enhance the signals with different amplification factors, and then transmit their respective multiple signals to the FPGA sampling module in sequence. Third, if the signal reaches the sampling trigger threshold and conditions, the two high-speed ADC controllers inside the FPGA sampling module start high-frequency sampling and perform analog-to-digital conversion to form two waveform data output through the serial communication interface; after the analog-to-digital conversion is completed, the FPGA sampling module will re-ready the sampling circuit in a very short time in order to identify the next current signal and perform analog-to-digital conversion again to output the data in the form of data from the serial communication interface. Fourth, after receiving all current pulse waveform data from the two acquisition channels within a short period of time, the MCU main control module breaks down each current data according to the data message and performs simple analysis on each data to confirm whether the waveform data of the two channels is saturated or distorted or the accuracy is insufficient. When a large current is measured, the waveform data of the small-range channel may be saturated or distorted, so the waveform data of the large-range channel is selected as the monitoring result; when a small current is measured, if the waveform data of the small-range channel is not saturated or distorted, the waveform data of the large-range channel may not accurately represent the current trend due to the small sampling value, so the waveform data of the small-range channel is selected as the monitoring result. That is, after receiving the data, the MCU main control module will perform comparative analysis and select the data under the optimal range. Fifth, each time a waveform data is received, the MCU main control module will obtain the GPS timestamp and location information in real time, and calibrate it to the local RTC with millisecond accuracy. Finally, the time and location information will be bound to each waveform data. Sixth, the data is encapsulated into frames according to a specific data protocol, stored in local memory, and then transmitted to a remote server platform via a 4G wireless communication module. The above is the complete current monitoring process of the multi-lightning current waveform monitoring system designed in this invention.

[0034] like Figure 3 As shown, this embodiment also proposes a software flow implementation scheme for the software configuration of the MCU main control module: First, after power-on, the MCU main control module initializes all the hardware peripherals used, including serial bus initialization, off-chip memory (FLASH, EEPROM) initialization, RTC clock initialization, and task and message queue initialization. Second, the main task loop polls to see if waveform data has been received; Third, after the serial port successfully receives a waveform data, it immediately reads the GPS data, parses the time and location information, binds it to the waveform data, and stores it in the message queue for caching; after receiving multiple data in a short interval, they are all cached in the message queue for processing by the main task. Fourth, in the main task, the waveform and time positioning data of all multiple pulses in the message queue are read sequentially, the extreme values, amplitude and other parameters of the two waveform data are compared and analyzed, and the waveform data under the optimal range is selected. Fifth, all waveform data, along with GPS time and location information, are packaged and encapsulated into data frames according to a specific data protocol; Sixth, the data is stored sequentially in local storage and then passed through to the 4G module for transmission to the server.

[0035] In summary, this embodiment can achieve lossless, distortion-free, high-precision monitoring of multiple lightning current waveforms across the entire range, with spatiotemporal calibration. Its core lies in: leveraging the parallel processing capabilities of the FPGA to ensure real-time processing of dual-channel data acquisition; relying on the FPGA's high-speed, high-precision AD sampling capabilities to meet the complete identification and measurement of multiple lightning currents with short intervals; utilizing dual acquisition paths with different ranges to cover a large dynamic range of lightning currents; and significantly improving time accuracy with the help of GPS signals.

[0036] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A dual-channel, multi-channel lightning strike current waveform monitoring system, characterized in that, include: Two acquisition coils, two sets of signal amplification circuits, an FPGA sampling module, and an MCU main control module; Two acquisition coils are connected to the FPGA sampling module through two sets of signal amplification circuits. The two sets of signal amplification circuits are used to filter and enhance the current signals generated by the two acquisition coils for the same lightning strike event, generating two analog signals. The two sets of signal amplification circuits have different amplification factors to configure channels with different ranges. The FPGA sampling module is connected to the MCU main control module through a data bus to perform high-frequency A / D sampling on the two analog signals and transmit the sampled and converted waveform data to the MCU main control module. The MCU main control module is used to compare and analyze the two waveform data corresponding to the same lightning strike event: if the waveform data of the channel with the smaller range does not experience saturation distortion, the waveform data of the channel with the smaller range is selected as the monitoring result; otherwise, the waveform data of the channel with the larger range is selected as the monitoring result.

2. The dual-channel multiple lightning strike current waveform monitoring system according to claim 1, characterized in that, Each signal amplification circuit includes a differential amplification circuit for suppressing common-mode interference signals and an anti-aliasing filter circuit for filtering out high-frequency interference noise; wherein, the two signal amplification circuits use amplification resistors with different resistance values.

3. The dual-channel multiple lightning strike current waveform monitoring system according to claim 1, characterized in that, The FPGA sampling module integrates a digital triggering unit, which generates a trigger signal based on preset waveform characteristic parameters. The waveform characteristic parameters include the current change rate and amplitude threshold. When the current waveform and amplitude of the analog signal exceed the corresponding threshold, sampling is triggered and converted into data, which is then transmitted to the MCU main control module through a serial communication interface.

4. The dual-channel multiple lightning strike current waveform monitoring system according to claim 3, characterized in that, The FPGA sampling module is also equipped with a multi-lightning strike identification and separation mechanism. This mechanism is used to trigger the sampling process after the rate of change and amplitude of the induced current reach a threshold. The sampling circuit is re-ready within a millisecond-level set time after completing one analog-to-digital conversion in order to capture and separate multiple return current pulses with millisecond-level intervals in the same lightning strike event.

5. The dual-channel multiple lightning strike current waveform monitoring system according to claim 1, characterized in that, It also includes a GPS positioning module; the GPS positioning module is used to provide time and positioning information for real-time recording of the time and location of the lightning current pulse.

6. The dual-channel multiple lightning strike current waveform monitoring system according to claim 5, characterized in that, It also includes a local storage module; the local storage module includes an EEPROM storage unit and a FLASH storage unit, both of which are connected to the MCU main control module in the form of a data bus and are used to store device parameters and lightning current waveform data.

7. A dual-channel multiple lightning strike current waveform monitoring system according to claim 6, characterized in that, The MCU main control module is also used to enable the local RTC clock and use the time information provided by the GPS positioning module to calibrate the local RTC clock in real time. When a lightning strike occurs, the MCU main control module uses the calibrated local RTC to record the millisecond-level timestamps of each return strike, and encapsulates the waveform data, timestamps and positioning information into a data frame, and controls the local storage unit to write the data frame into the FLASH storage unit for backup.

8. A dual-channel multiple lightning strike current waveform monitoring system according to claim 7, characterized in that, It also includes a 4G communication module; the 4G communication module is used to establish a connection with a remote server via the TCP protocol and maintain the connection via heartbeat packets; the MCU main control module is also used to transmit the encapsulated data frames to the server via the 4G communication module.

9. A dual-channel multiple lightning strike current waveform monitoring system according to claim 8, characterized in that, It also includes a power supply circuit; the power supply circuit is electrically connected to the MCU main control module, FPGA sampling module, GPS positioning module, local storage module and 4G communication module, and is used to provide operating voltage for each module.

10. A dual-channel multiple lightning strike current waveform monitoring system according to claim 1, characterized in that, The acquisition coil is a Rogowski coil.

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