Magnetic stripe lightning current recording card analysis system and analysis method

Abstract

The invention discloses a magnetic stripe lightning current recording card analysis system and analysis method, the system comprises an upper computer and a computer end which are in electric signal connection, the upper computer comprises an upper computer control module, a card reader, a residual magnetism acquisition module and an AD acquisition module, and the computer end comprises an AD analysis module. The method comprises the following steps: inserting a magnetic strip lightning current recording card into a card reader, collecting and processing residual magnetism in the recording card, outputting a residual magnetism voltage waveform, processing and converting the residual magnetism voltage waveform into an AD waveform, and uploading the AD waveform to an AD analysis module for calculation to obtain an integral area; and calibrating the magnetic strip lightning current recording card to obtain a calibration function, and substituting the integral area into the calibration function to obtain a peak current. According to the invention, through combination of the upper computer system and the computer end system, reading of the magnetic stripe type thunder peak current recording card installed under any cable or structure is realized, the application scenarios of the magnetic stripe type thunder peak current recording card are greatly increased, and the peak current of lightning stroke under different scenarios can be accurately analyzed.

Description

Technical Field

[0001] The invention belongs to the technical field of lightning monitoring, and in particular relates to a magnetic stripe lightning current recording card analysis system. The invention also relates to an analysis method of the above analysis system. Background Art

[0002] Wind farms are generally built in open or high-altitude areas with sufficient wind power, which can easily meet the needs of wind power generation. However, due to the high height of the wind turbine and the lack of any shelter around it, it is easy to be struck by direct lightning. During the lightning strike, the wind turbine blades and electrical equipment of the wind farm are prone to lightning damage. In severe cases, the wind turbine blades will be broken, causing the wind turbine to fail to work properly. This has a serious impact on the power generation of the wind farm. In order to obtain accurate lightning signals as evidence for insurance claims, wind farms usually use magnetic stripe lightning peak current recording cards to record lightning peak currents. The magnetic stripe lightning recording card is installed on one side of the cable or equipment. The current passing through the equipment or cable will generate a strong magnetic field around it, which will demagnetize the magnetic stripe of the magnetic stripe lightning peak recording card. Since the current distribution after the current is conducted in different structures is different, different current distributions will generate different magnetic fields in space, and different magnetic fields will also demagnetize the magnetic stripe differently.

[0003] However, the existing magnetic stripe lightning peak current recording card analysis is usually calibrated with ordinary wind turbine lightning down conductors, and can only correctly analyze the monitoring current of the lightning peak current recording card on ordinary down conductors, resulting in the existing magnetic stripe lightning peak current recording card being limited to specific cable models, and the usage scenarios are very limited. If the magnetic stripe lightning peak current recording card is installed at other cable locations or on the side of the equipment, the magnetic stripe lightning peak current recording card cannot be correctly analyzed or cannot be analyzed directly, and the recorded lightning peak current is inconsistent with the actual lightning peak current, thereby affecting the insurance claim of the wind turbine or wind turbine blades. Summary of the invention

[0004] The purpose of the present invention is to provide a magnetic stripe lightning current recording card analysis system, which can read the magnetic stripe lightning peak current recording card installed under any cable or structure through the combination of a host computer system and a computer-side system, greatly increasing the application scenarios of the magnetic stripe lightning peak current recording card, and can accurately analyze the peak current of lightning strikes in different scenarios.

[0005] Another object of the present invention is to provide a method for analyzing a magnetic stripe lightning current recording card.

[0006] The first technical solution adopted by the present invention is a magnetic stripe lightning current recording card analysis system, including a host computer and a computer end connected by electrical signals, the host computer includes a host computer control module, the host computer control module is connected to a card reader through electrical signals, the card reader is provided with a residual magnetism acquisition module for collecting the residual magnetism of the magnetic stripe lightning current recording card and an AD acquisition module for performing AD conversion, the residual magnetism acquisition module and the AD acquisition module are electrically connected to the host computer control module by signals; the computer end includes an AD analysis module for analyzing the peak current in the calibration mode, and the AD analysis module is electrically connected to the host computer control module by signals.

[0007] Furthermore, the residual magnetism acquisition module includes:

[0008] A residual magnetic field acquisition probe that emits a sinusoidal magnetic field signal to a magnetic stripe lightning current recording card;

[0009] A magnetoelectric conversion module that converts a sinusoidal oscillation signal into an analog voltage sinusoidal oscillation signal;

[0010] A high-frequency AD waveform acquisition module that converts analog voltage sinusoidal oscillation signals into digital sinusoidal oscillation signals;

[0011] The magnetoelectric conversion module is electrically connected to the high-frequency AD waveform acquisition module.

[0012] Another technical solution adopted by the present invention is a magnetic stripe lightning current recording card analysis method, which specifically includes the following steps:

[0013] Step 1: insert the magnetic stripe lightning current recording card into the card reader, and the residual magnetism acquisition module collects and processes the residual magnetism in the magnetic stripe lightning current recording card and outputs the residual magnetism voltage waveform to the AD acquisition module;

[0014] Step 2: The AD acquisition module processes and transforms the residual magnetic voltage waveform into an AD waveform, and transmits the AD waveform to the host computer control module;

[0015] Step 3, the host computer control module uploads the AD waveform to the AD analysis module, and the AD analysis module calculates the AD waveform to obtain the integral area;

[0016] Step 4: The computer calibrates the magnetic stripe lightning current recording card to obtain a calibration function. The integral area obtained in step 3 is substituted into the calibration function to obtain the peak current of the magnetic stripe lightning current recording card to complete the analysis.

[0017] Furthermore, in step 1, the residual magnetism in the magnetic stripe lightning current recording card is collected and processed specifically by moving the residual magnetism collection probe at a uniform speed above the magnetic stripe, the residual magnetism collection probe sends out a sinusoidal magnetic field signal, and the residual magnetism in the magnetic stripe lightning current recording card sends out a sinusoidal oscillation signal after receiving the sinusoidal magnetic field signal. The magnetoelectric conversion module converts the sinusoidal oscillation signal into an analog voltage sinusoidal oscillation signal, and the high-frequency AD waveform collection module converts the analog voltage sinusoidal oscillation signal into a digital sinusoidal oscillation signal, and performs frequency reduction processing on the collected digital sinusoidal oscillation signal to output a frequency-reduced voltage sinusoidal oscillation signal, that is, a residual magnetism voltage waveform.

[0018] Furthermore, the processing of the residual magnetic voltage waveform in step 2 is specifically as follows: first, the residual magnetic voltage waveform is subjected to preliminary noise reduction to obtain an analog envelope waveform, wherein the preliminary noise reduction is envelope detection and low-pass filtering, and then the analog envelope waveform is AD-converted into a digital envelope waveform, and the digital envelope waveform is subjected to exception processing and normalization processing and then output as an AD waveform.

[0019] Furthermore, the integral area calculation in step 3 is specifically as follows:

[0020]

[0021] Where s is the integrated area of ​​the AD waveform, i is the number of any data point of the AD waveform, (X i , Y i ) is the coordinate of any numerical point of the AD waveform, and N is the last data point number of the AD waveform.

[0022] Furthermore, the calibration of the magnetic stripe lightning current recording card in step 4 is specifically that the computer terminal performs the same lightning simulation experiment as the magnetic stripe lightning current recording card, and the magnetic stripe card in the simulation experiment is analyzed with a fixed peak current to obtain an AD waveform under the simulation experiment, thereby forming a calibration between the fixed peak current and the AD waveform;

[0023] Then, the magnetic field around the cable is calculated through finite element numerical simulation, and the simulated residual magnetism waveform under the fixed peak current is obtained by subtracting the magnetic coercive force on the magnetic stripe card from the magnetic field around the cable, completing the calibration between the fixed peak current and the simulated residual magnetism waveform. Since the fixed peak current and the AD waveform have been calibrated, the calibration between the AD waveform and the simulated residual magnetism waveform is further completed;

[0024] When the magnetic field around the cable is measured, the simulated residual magnetism waveform of the magnetic stripe card is deduced according to the calculated integrated area of ​​the AD waveform, and then the peak current of the magnetic stripe card is deduced through the simulated residual magnetism waveform.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] (1) A magnetic stripe lightning current recording card analysis system of the present invention uploads the AD value of the host computer to the computer end through the serial port. The host computer end is responsible for controlling the card machine and the magnetic sensor to collect AD and perform low-computation tasks such as envelope, low-pass filtering and denoising. The computer end is responsible for analyzing the stable AD. At the same time, the computer end will perform real-time calibration based on the structural data of the installed cable and the installation position of the magnetic stripe lightning current recording card, so as to realize reading the magnetic stripe lightning peak current recording card installed under any cable or structure, which greatly increases the application scenarios of the magnetic stripe lightning peak current recording card and can accurately analyze the peak current of lightning strikes in different scenarios.

[0027] (2) The present invention can complete the calibration of the peak magnetic field and the magnetic stripe type lightning peak current recording card through finite element numerical calculation under the same test environment. Therefore, when the magnetic stripe type lightning peak current recording card is installed on other cables or equipment, the calibration can be completed quickly by accurately calculating the peak magnetic field of the magnetic stripe type lightning peak current recording card, without the need for repeated tests, which greatly reduces the test cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a structural schematic diagram of a magnetic stripe lightning current recording card analysis system of the present invention;

[0029] Figure 2 It is a flow chart of a magnetic stripe lightning current recording card analysis method of the present invention;

[0030] Figure 3 It is an abnormal processing diagram of step 2 in a magnetic stripe lightning current recording card analysis method of the present invention;

[0031] Figure 4 It is a normalized processing diagram of step 2 in a magnetic stripe lightning current recording card analysis method of the present invention;

[0032] Figure 5 It is a calibration relationship diagram of step 4 in a magnetic stripe lightning current recording card analysis method of the present invention.

[0033] In the figure, 1. host computer control module, 2. card reader, 3. residual magnetic acquisition module, 4. AD acquisition module, 5. AD analysis module, 6. residual magnetic acquisition probe, 7. magnetoelectric conversion module, 8. high-frequency AD waveform acquisition module. DETAILED DESCRIPTION

[0034] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments in the invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0035] The structure of a magnetic stripe lightning current recording card analysis system of the present invention is as follows Figure 1 As shown, it includes a host computer and a computer terminal connected by electrical signals, the host computer includes a host computer control module 1, the host computer control module 1 is connected to a card reader 2 through electrical signals, the card reader 2 is provided with a residual magnetism acquisition module 3 for collecting the residual magnetism of a magnetic stripe lightning current recording card and an AD acquisition module 4 for performing AD conversion, the residual magnetism acquisition module 3 and the AD acquisition module 4 are connected to the host computer control module 1 by electrical signals.

[0036] The residual magnetic field acquisition module 3 includes:

[0037] A residual magnetic field acquisition probe 6 that emits a sinusoidal magnetic field signal to the magnetic stripe lightning current recording card. The residual magnetic field acquisition probe 6 is mainly a transmitting probe connected to a sinusoidal signal generator. The sinusoidal signal generator used in the scheme of the present invention is a purchased model AWA1651 sinusoidal signal generator;

[0038] A magnetoelectric conversion module 7 for converting a sinusoidal oscillation signal into an analog voltage sinusoidal oscillation signal;

[0039] A high-frequency AD waveform acquisition module 8 that converts an analog voltage sinusoidal oscillation signal into a digital sinusoidal oscillation signal;

[0040] The magnetoelectric conversion module 7 is electrically connected to the high-frequency AD waveform acquisition module 8 .

[0041] The computer terminal includes an AD analysis module 5 for analyzing the peak current in the calibration mode, and the AD analysis module 5 is connected to the host computer control module 1 by electrical signals.

[0042] The magnetic stripe type lightning peak current recording card is a magnetic stripe card. The card itself is made of PVC material and has 1 to 2 magnetic stripes on the back. When struck by lightning, the magnetic field generated by the lightning current will demagnetize the magnetic stripe on the card. The current size has different demagnetizing effects on the magnetic stripe. Based on this principle, the magnetic stripe card can be used to record the lightning peak current.

[0043] like Figure 2 As shown, a magnetic stripe lightning current recording card analysis method of the present invention specifically includes the following steps:

[0044] Step 1: insert the magnetic stripe lightning current recording card into the card reader 2, and the residual magnetism acquisition module 3 collects and processes the residual magnetism in the magnetic stripe lightning current recording card and outputs the residual magnetism voltage waveform to the AD acquisition module 4.

[0045] Specifically, the residual magnetism acquisition probe 6 moves at a constant speed above the magnetic stripe, and the residual magnetism acquisition probe 6 emits a sinusoidal magnetic field signal of a certain base frequency. After receiving the sinusoidal magnetic field signal, the residual magnetism in the magnetic stripe lightning current recording card emits a sinusoidal oscillation signal. Different residual magnetisms will produce different sinusoidal oscillation signals. The magnetoelectric conversion module 7 converts the sinusoidal oscillation signal into an analog voltage sinusoidal oscillation signal, and the high-frequency AD waveform acquisition module 8 converts the analog voltage sinusoidal oscillation signal into a digital sinusoidal oscillation signal, and performs frequency reduction processing on the collected digital sinusoidal oscillation signal, and outputs a frequency-reduced voltage sinusoidal oscillation signal, that is, a residual magnetism voltage waveform.

[0046] Step 2, the AD acquisition module 4 processes and transforms the residual magnetic voltage waveform into an AD waveform, and transmits the AD waveform to the upper computer control module 1.

[0047] Specifically, the residual magnetic voltage waveform is first subjected to envelope detection and low-pass filtering to complete the preliminary noise reduction of the residual magnetic voltage waveform and obtain an analog envelope waveform. The analog envelope waveform is then converted from AD to a digital envelope waveform. Finally, the digital envelope waveform is subjected to exception processing and normalization to obtain an AD waveform for output.

[0048] like Figure 3 As shown, the abnormality processing includes further denoising the digital envelope waveform through wavelet transform to remove the waveform abnormality caused by waveform conversion or magnetic stripe card process. The wavelet transform to remove the digital waveform abnormality is specifically as follows: firstly, the digital envelope waveform after AD conversion is decomposed by wavelet to obtain multiple frequency variables, and then each frequency variable is thresholded to remove the noise, and the denoised waveform is synthesized to obtain a smooth signal waveform.

[0049] There is a certain jitter and unevenness in the mechanical transmission of the card reader 2 when reading the card. The collected waveform signal has a certain time difference locally and overall, resulting in a certain difference in the waveform in time. This difference will bring about errors in collection and errors in the inverted current results. Through exception processing, the impact of errors in collection and errors in the inverted current results can be effectively reduced, thereby improving the accuracy of the output AD waveform.

[0050] like Figure 4 As shown, the normalization process is to fix multiple signal acquisition points at a specific and unified time point, so that the acquisition signals of the same magnetic stripe card are consistent in time under any mechanical jitter or delay, and the errors caused by inconsistent demagnetization mechanical movement are eliminated, further improving the accuracy of the subsequent peak current analysis.

[0051] Step 3, the host computer control module 1 uploads the AD waveform to the AD analysis module 5, and the AD analysis module 5 calculates the AD waveform to obtain the integral area. The specific calculation formula is as follows:

[0052]

[0053] Where s is the integrated area of ​​the AD waveform, i is the number of any data point of the AD waveform, (X i , Y i ) is the coordinate of any numerical point of the AD waveform, and N is the last data point number of the AD waveform.

[0054] Step 4: The computer calibrates the magnetic stripe lightning current recording card, and the integral area of ​​the AD waveform obtained in step 3 is brought into the calibration of the magnetic stripe lightning current recording card to obtain the peak current of the magnetic stripe lightning current recording card, thereby completing the analysis.

[0055] like Figure 5 As shown, the calibration of the magnetic stripe lightning current recording card in step 4 is specifically to perform the same lightning simulation experiment as the magnetic stripe lightning current recording card on the computer side, and to analyze the magnetic stripe card in the simulation experiment with a fixed peak current to obtain the AD waveform under the simulation experiment, thereby forming a calibration between the fixed peak current and the AD waveform;

[0056] Then, the magnetic field around the cable is calculated by finite element numerical simulation. Since the magnetic coercivity of the magnetic stripe card is a fixed value, the relationship between the fixed peak current and the magnetic field around the cable is uniquely corresponding to each other. Then, the simulated residual magnetism waveform under the fixed peak current is obtained by subtracting the magnetic coercivity on the magnetic stripe card from the magnetic field around the cable. Since the magnetic coercivity value is fixed, there are only two variables between the simulated residual magnetism waveform and the magnetic field around the cable. Therefore, the simulated residual magnetism waveform and the magnetic field around the cable are uniquely corresponding to each other, that is, the calibration between the fixed peak current and the simulated residual magnetism waveform is completed. Since the fixed peak current and the AD waveform are calibrated, the calibration between the AD waveform and the simulated residual magnetism waveform is further completed.

[0057] That is, when the magnetic field around the cable is measured, the simulated residual magnetism waveform of the magnetic stripe card is calculated according to the calculated integral area of ​​the AD waveform, and then the peak current of the magnetic stripe card is calculated through the simulated residual magnetism waveform.

[0058] The technical solution of the present invention can complete the calibration of the peak magnetic field, current and magnetic stripe type lightning peak current recording card by simulating the finite element numerical calculation under the same test environment. The magnetic stripe type lightning peak current recording card can be installed on any cable or structure. As long as the peak magnetic field of the magnetic stripe type lightning peak current recording card is measured, the calibration can be completed quickly without repeated tests, which greatly reduces the test cost and breaks the existing magnetic stripe type lightning peak current recording card analysis technology that can only analyze the magnetic stripe type lightning peak current recording card installed on a specific cable model, greatly increasing the application scenarios of the magnetic stripe type lightning peak current recording card.

Claims

1. A magnetic stripe lightning current recording card analysis system, characterized in that: The invention comprises a host computer and a computer terminal connected by electrical signals, wherein the host computer comprises a host computer control module (1), the host computer control module (1) is connected to a card reader (2) by electrical signals, the card reader (2) is provided with a residual magnetism acquisition module (3) for acquiring residual magnetism of a magnetic stripe lightning current recording card and an AD acquisition module (4) for performing AD conversion, the residual magnetism acquisition module (3) and the AD acquisition module (4) being connected to the host computer control module (1) by electrical signals; and the computer terminal comprises an AD analysis module (5) for analyzing peak current in a calibration mode, the AD analysis module (5) being connected to the host computer control module (1) by electrical signals.

2. A magnetic stripe lightning current recording card analysis system according to claim 1, characterized in that: The residual magnetism acquisition module (3) comprises: A residual magnetic field acquisition probe (6) that emits a sinusoidal magnetic field signal to a magnetic stripe lightning current recording card; A magnetoelectric conversion module (7) for converting a sinusoidal oscillation signal into an analog voltage sinusoidal oscillation signal; A high-frequency AD waveform acquisition module (8) that converts an analog voltage sinusoidal oscillation signal into a digital sinusoidal oscillation signal; The magnetoelectric conversion module (7) is electrically connected to the high-frequency AD waveform acquisition module (8).

3. A magnetic stripe lightning current recording card analysis method, using a magnetic stripe lightning current recording card analysis system as claimed in claim 2, characterized in that: The specific steps include: Step 1, inserting a magnetic stripe lightning current recording card into a card reader (2), and the residual magnetism acquisition module (3) collects and processes the residual magnetism in the magnetic stripe lightning current recording card and outputs a residual magnetism voltage waveform to the AD acquisition module (4); Step 2, the AD acquisition module (4) processes and transforms the residual magnetic voltage waveform into an AD waveform, and transmits the AD waveform to the upper computer control module (1); Step 3, the host computer control module (1) uploads the AD waveform to the AD analysis module (5), and the AD analysis module (5) calculates the AD waveform to obtain the integral area; Step 4: The computer calibrates the magnetic stripe lightning current recording card to obtain a calibration function. The integral area obtained in step 3 is substituted into the calibration function to obtain the peak current of the magnetic stripe lightning current recording card to complete the analysis.

4. A magnetic stripe lightning current recording card analysis method according to claim 3, characterized in that: In the step 1, the residual magnetism in the magnetic stripe lightning current recording card is collected and processed specifically as follows: the residual magnetism collection probe (6) moves at a uniform speed above the magnetic stripe, the residual magnetism collection probe sends out a sinusoidal magnetic field signal, the residual magnetism in the magnetic stripe lightning current recording card sends out a sinusoidal oscillation signal after receiving the sinusoidal magnetic field signal, the magnetoelectric conversion module (7) converts the sinusoidal oscillation signal into an analog voltage sinusoidal oscillation signal, the high-frequency AD waveform collection module (8) converts the analog voltage sinusoidal oscillation signal into a digital sinusoidal oscillation signal, and performs frequency reduction processing on the collected digital sinusoidal oscillation signal to output a frequency-reduced voltage sinusoidal oscillation signal, i.e., a residual magnetism voltage waveform.

5. A magnetic stripe lightning current recording card analysis method according to claim 3, characterized in that: The processing of the residual magnetic voltage waveform in step 2 is specifically as follows: first, the residual magnetic voltage waveform is subjected to preliminary noise reduction to obtain an analog envelope waveform, wherein the preliminary noise reduction is envelope detection and low-pass filtering, and then the analog envelope waveform is AD-converted into a digital envelope waveform, and the digital envelope waveform is subjected to exception processing and normalization processing before being output as an AD waveform.

6. A magnetic stripe lightning current recording card analysis method according to claim 3, characterized in that: The integral area calculation in step 3 is specifically as follows: Where s is the integrated area of ​​the AD waveform, i is the number of any data point of the AD waveform, (X i , Y i ) is the coordinate of any numerical point of the AD waveform, and N is the last data point number of the AD waveform.

7. A magnetic stripe lightning current recording card analysis method according to claim 3, characterized in that: The calibration of the magnetic stripe lightning current recording card in step 4 is specifically as follows: the computer terminal performs the same lightning simulation experiment as the magnetic stripe lightning current recording card, and the magnetic stripe card in the simulation experiment is analyzed with a fixed peak current to obtain an AD waveform under the simulation experiment, thereby forming a calibration between the fixed peak current and the AD waveform; Then, the magnetic field around the cable is calculated through finite element numerical simulation, and the simulated residual magnetism waveform under the fixed peak current is obtained by subtracting the magnetic coercive force on the magnetic stripe card from the magnetic field around the cable, completing the calibration between the fixed peak current and the simulated residual magnetism waveform. Since the fixed peak current and the AD waveform have been calibrated, the calibration between the AD waveform and the simulated residual magnetism waveform is further completed; When the magnetic field around the cable is measured, the simulated residual magnetism waveform of the magnetic stripe card is deduced according to the calculated integrated area of ​​the AD waveform, and then the peak current of the magnetic stripe card is deduced through the simulated residual magnetism waveform.

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