Method and system for measuring leakage current of lightning arrester based on iterative compensation method

Abstract

The invention discloses a lightning arrester leakage current measurement method and system based on an iterative compensation method, and the system comprises an annular mutual inductor, and a sampling module, a transmission module and a storage module which are connected with a calculation module, and is used for executing the lightning arrester leakage current measurement method. During measurement, according to a set data sampling period, voltage sampling is carried out on the two ends of an annular mutual inductor in the lightning arrester leakage current detection system regularly and repeatedly to obtain multiple output voltages, and the obtained multiple output voltages are subjected to multiple iterative calculations to obtain output leakage current. The output leakage current after multiple times of iteration compensation is used for eliminating interference brought by induced electromotive force, and the monitoring effect on the leakage current of the lightning arrester is remarkably improved. Safe and stable operation of the electric power system is guaranteed, potential problems can be found in time, reliable data support is provided for maintenance and management of equipment, and therefore the overall safety and reliability of the electric power system are guaranteed.

Description

Technical Field

[0001] The invention relates to the technical field of arrester leakage current measurement, and in particular to an arrester leakage current measurement method and system based on an iterative compensation method. Background Art

[0002] In power transmission and transformation equipment, lightning arresters are an important protective device, and their role in the power system is indispensable. The main function of lightning arresters is to protect various types of electrical equipment from being damaged by overvoltages caused by lightning, overvoltages generated by operation, and power frequency transient overvoltages. Since these overvoltage events may cause serious damage to the equipment, the effectiveness and reliability of lightning arresters are crucial. In addition, there are many types of lightning arresters, mainly including protective gap lightning arresters, valve type lightning arresters, and zinc oxide lightning arresters. These lightning arresters each have their own specific application scenarios and protection mechanisms. But no matter what type of lightning arrester, what they have in common is that they need to use effective monitoring methods to evaluate their working status. Among them, the monitoring of lightning arrester leakage current is particularly prominent. The change in leakage current can not only reflect the health status of the lightning arrester, but also predict potential failure risks to a certain extent.

[0003] In practical applications, we usually use toroidal mutual inductors to measure the leakage current of lightning arresters. However, in the process of measuring the leakage current, the change in current will cause an induced electromotive force to be generated at both ends of the coil, thereby causing measurement errors in the leakage circuit. Induced electromotive force refers to the induced electromotive force excited in the circuit when the magnetic field changes while the coil is stationary. However, the measurement error caused by the induced electromotive force may have an adverse effect on the accuracy of the measurement results, greatly reducing the measurement accuracy of the leakage current. This is not only not conducive to ensuring the safe and stable operation of the power system, but also cannot ensure the safety and reliability of the power system operation. Therefore, it becomes particularly important to eliminate the potential difference caused by the change in leakage current, and there is an urgent need for a method and system that can accurately measure the leakage current of the lightning arrester. Summary of the invention

[0004] The content of this application is used to introduce concepts in a brief form, which will be described in detail in the detailed implementation section below. The content of this application is not intended to identify the key features or essential features of the technical solution claimed for protection, nor is it intended to limit the scope of the technical solution claimed for protection.

[0005] In view of the problems and shortcomings in the prior art, the present invention aims to provide a lightning arrester leakage current measurement system and method based on an iterative compensation method, which can eliminate the error caused by the induced electromotive force generated by the leakage current change through the iterative compensation method, thereby improving the accuracy of leakage current measurement, which is of great significance for the monitoring of lightning arrester leakage current. In order to solve the problems raised in the above background technology.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] As a first aspect of the present application, the present invention discloses a method for measuring leakage current of a lightning arrester based on an iterative compensation method, which specifically comprises the following steps:

[0008] Step 1, initialize the arrester leakage current measurement system and set the data sampling period to wake up the system regularly;

[0009] Step 2, sampling the voltage at both ends of the toroidal transformer of the arrester leakage current measurement system to obtain an initial output voltage, and calculating an initial leakage current;

[0010] Step 3, sampling the two ends of the toroidal transformer multiple times based on the data sampling period to obtain multiple output voltages, and then calculating the leakage current multiple times in combination with the initial leakage current;

[0011] Step 4: Use the current output voltage and the previous leakage current to calculate the output leakage current through multiple iterations.

[0012] Furthermore, the calculation formula of the initial leakage current is:

[0013]

[0014] Among them, I 0 Expressed as the initial leakage current, V 0 It is represented as the initial output voltage, k is represented as the coefficient obtained from the calibration, Δt is represented as the time difference of the magnetic field change, and b is represented as a certain constant.

[0015] Furthermore, the iterative calculation formula of the output leakage current is:

[0016]

[0017] Among them, I n Represented as the output leakage current calculated for the nth time, I n-1 Indicated as the value of the previous output leakage current, V n It is expressed as the output voltage detected for the nth time.

[0018] Furthermore, the two ends of the toroidal mutual inductor are sampled five times respectively according to the data sampling period, and the final output leakage current is obtained through five iterative calculations.

[0019] As a second aspect of the present application, the present invention further discloses a lightning arrester leakage current measurement system based on an iterative compensation method, which is used to perform the above-mentioned lightning arrester leakage current measurement method, comprising:

[0020] A toroidal transformer and a lightning arrester, wherein the toroidal transformer comprises an annular core and a coil, wherein the coil is wound around the outside of the annular core, and the lightning arrester is arranged through the annular core;

[0021] A sampling module, used to amplify and sample the output voltage collected from the input and output lines of the toroidal transformer according to a preset period;

[0022] A calculation module, used for receiving the output voltage collected by the sampling module to calculate the output leakage current of the arrester;

[0023] A storage module, used for effectively and quickly storing the data calculated and processed by the calculation module;

[0024] The transmission module is used to transmit the output leakage current data that needs to be sent.

[0025] Furthermore, the calculation module includes an MCU control chip, and the MCU control chip includes a plurality of calculation units, and the calculation units are used to perform iterative operations on the magnetic field intensity, electromotive force, output voltage and leakage current respectively.

[0026] Furthermore, the sampling module includes an operational amplifier and a multiplexer, the input and output lines of the toroidal transformer are connected to the input end of the operational amplifier, the input and output ends of the operational amplifier are bridged across the multiplexer, and the multiplexer is connected to the MCU control chip via the ADC serial port.

[0027] Furthermore, the storage module includes a storage chip, which is connected to the MCU control chip via an SPI bus, a chip select terminal and a write terminal of the storage chip are both connected in series with resistors, and a power supply terminal of the storage chip is connected in series with a capacitor and then grounded.

[0028] Furthermore, the transmission module includes a time-controlled switch and a connector. The time-controlled switch is connected to the MCU control chip through a serial port. The RF end of the time-controlled switch is connected to the connector after a resistor is connected in series, and data is transmitted externally through the connector.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] The invention discloses a lightning arrester leakage current measurement method based on an iterative compensation method. According to the data sampling cycle, the voltage sampling of the two ends of the ring mutual inductor in the lightning arrester leakage current detection system is performed multiple times at regular intervals to obtain multiple output voltages, and the output leakage current is obtained by using the obtained multiple output voltages through multiple iterative calculations. The output leakage current after multiple iterative compensation can eliminate the interference caused by the induced electromotive force, and significantly improve the monitoring effect of the lightning arrester leakage current. It not only helps to ensure the safe and stable operation of the power system, but also can timely discover potential problems and provide reliable data support for the maintenance and management of the equipment, thereby ensuring the overall safety and reliability of the power system. In addition, a lightning arrester leakage current measurement system based on an iterative compensation method is also disclosed, including a ring mutual inductor and a sampling module, a transmission module and a storage module connected to a calculation module. The sampling module is used to collect the output voltage at both ends of the ring mutual inductor, and the output voltage is converted into a digital signal and transmitted to the calculation module. The lightning arrester leakage current corresponding to the output voltage is calculated by the calculation module, and then the data is transmitted in combination with the transmission module. When in use, the storage module can also be used to store and retain the data and instructions generated during the collection and calculation process. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The drawings constituting a part of this application are used to provide a further understanding of this application, so that other features, purposes and advantages of this application become more obvious. The illustrative embodiment drawings and their descriptions of this application are used to explain this application and do not constitute an improper limitation on this application.

[0032] In the attached picture:

[0033] Figure 1 A flowchart of the method for measuring leakage current of a lightning arrester according to the present application;

[0034] Figure 2 A flowchart of the steps of the method for measuring the leakage current of a lightning arrester of the present application;

[0035] Figure 3 This is a structural diagram of a toroidal transformer in the lightning arrester leakage current measurement system of the present application;

[0036] Figure 4 This is a connection structure block diagram of the arrester leakage current measurement system of this application;

[0037] Figure 5 This is a connection circuit diagram of the MCU control chip in the lightning arrester leakage current measurement system of this application;

[0038] Figure 6 This is the pin connection diagram of the MCU control chip in the lightning arrester leakage current measurement system of this application;

[0039] Figure 7A pin connection diagram of a storage module in the arrester leakage current measurement system of this application;

[0040] Figure 8 This is the pin connection diagram of the transmission module in the lightning arrester leakage current measurement system of this application.

[0041] Marked in the figure: 10, lightning arrester; 11, ring iron core; 12, coil. DETAILED DESCRIPTION

[0042] Embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although certain embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be construed as being limited to the embodiments set forth herein. On the contrary, these embodiments are provided to provide a more thorough and complete understanding of the present disclosure. It should be understood that the drawings and embodiments of the present disclosure are only for exemplary purposes and are not intended to limit the scope of protection of the present disclosure.

[0043] It should also be noted that, for ease of description, only the parts related to the invention are shown in the drawings. In the absence of conflict, the embodiments and features in the embodiments of the present disclosure can be combined with each other.

[0044] Example

[0045] The present disclosure will be described in detail below with reference to the accompanying drawings and in combination with embodiments. Figure 1 shown.

[0046] This embodiment provides a method for measuring the leakage current of a lightning arrester based on an iterative compensation method, which specifically includes the following steps:

[0047] Step 1, initialize the arrester leakage current measurement system and set the data sampling period to wake up the system regularly;

[0048] Step 2, sampling the voltage at both ends of the toroidal transformer of the arrester leakage current measurement system to obtain an initial output voltage, and calculating the initial leakage current;

[0049] Step 3, sampling the two ends of the toroidal transformer multiple times based on the data sampling period to obtain multiple output voltages, and then calculating the multiple leakage currents in combination with the initial leakage current;

[0050] Step 4: Use the current output voltage and the previous leakage current to calculate the output leakage current through multiple iterations.

[0051] Specifically, Figure 3The toroidal transformer used in this embodiment includes a toroidal core 11 and a coil 12 wound on the outside of the toroidal core 11. At present, the method for measuring leakage current is to calculate the arrester leakage current by using the current relationship (V=kI) between the voltage V at both ends of the coil and the current I passing through. Among them, V represents the output voltage of the toroidal transformer, I represents the output current passing through the toroidal transformer, that is, the arrester leakage current, and k represents the coefficient obtained from the calibration.

[0052] However, during the measurement process, since the arrester leakage current is constantly changing, the magnetic field at the coil will also change with the change of the arrester leakage current. This change can be analyzed by calculation. The change in magnetic field strength can be used to describe the change in magnetic field strength in space, expressed as Among them, μ 0 is the dielectric constant, R is the magnetic field radius of the coil, and ΔI is the change in current. Then the electromotive force generated by the change in magnetic field is expressed as That is the induced electromotive force. This is because when the coil is stationary and the magnetic field changes, the magnetic flux passing through the loop is also changing, and the induced electromotive force excited in the loop is called the induced electromotive force. In the above induced electromotive force ε formula, n represents the number of turns of the coil, and Δt represents the time difference of the magnetic field change. In order to simplify the writing and make the formula look simpler, we set a certain constant b in a certain toroidal mutual inductor. And let the constant Calculate, then the induced electromotive force ε generated at both ends of the coil due to the current change changes to In the toroidal transformer, the induced electromotive force ε appears as an induced voltage across the coil.

[0053] Usually, when the induced electromotive force is not considered, our normal measurement method is based on the above current relationship V = kI, and the output voltage measured at both ends of the coil is reversed to obtain the leakage current I, which is expressed as However, the measurement error caused by induced electromotive force is inevitable and must be given sufficient attention. Then after we consider the induced electromotive force, the output voltage actually measured will be expressed as Then the actual leakage current I can be expressed as This is consistent with the above formula The invention discloses an iterative compensation method, collects the output voltage multiple times, and uses the leakage current value obtained from the last collection to derive a new value, so as to reduce the measurement error caused by the induced electromotive force.

[0054] Reference Figure 2As shown, first initialize the arrester leakage current measurement system and set the data sampling period to wake up the system regularly. We need to perform the initial sampling on both ends of the ring transformer in the arrester leakage current detection system to obtain the initial output voltage V 0 For sampling, the initial leakage current before the first sampling is not monitored and is therefore zero. Therefore, according to the above leakage current formula The initial leakage current I 0 The calculation formula is expressed as Among them, I 0 Expressed as the initial leakage current, V 0 is the initial output voltage, k is the coefficient obtained from the calibration, Δt is the time difference of the magnetic field change, b is a certain constant, and the I calculated here is 0 The error caused by the induced electromotive force is not eliminated. Here, we assume that an initial error value for comparison is expressed as m 0 , then the actual initial leakage current should be minus the initial error value m 0 Represented as I 0 -m 0 Then perform the second sampling (also the first iteration calculation), sample the output voltage at both ends of the ring coil to obtain the second output voltage V 1 , considering the influence of induced electromotive force, according to the above leakage current formula The leakage current of the next cycle is obtained. Combined with the initial error value m, the actual second leakage current should be expressed as The second error value m 1 is caused by the inaccurate initial leakage current, then the second error value m 1 Expressed as It can be seen that in the above formula, k>0, so From this we can conclude So m 1 <m 0 , that is, the error decreases after one iteration, which means that the more iterations, the more accurate the measured data will be. The iterative calculation formula for the output leakage current can be expressed as Among them, I n Represented as the output leakage current calculated for the nth time, I n-1 Indicated as the value of the previous output leakage current, V n The output voltage detected for the nth time is represented. In order to take the operation time and cycle into consideration, in this embodiment, the iteration is terminated after five cycles.

[0055] This embodiment also provides a lightning arrester leakage current measurement system based on an iterative compensation method, such as Figure 3 and Figure 4 As shown, it includes a lightning arrester 10, a toroidal transformer, a sampling module, a computing module, a storage module and a transmission module. The storage module, the transmission module and the sampling module are all connected to the computing module, the storage module and the computing module are connected via an SPI bus, the transmission module and the computing module are connected via a serial port, and the sampling module and the computing module are connected via an ADC serial port. The sampling module is connected to the input and output lines of the toroidal transformer, and the voltage collected by the input and output lines of the toroidal transformer is amplified and sampled by an operational amplifier circuit. The computing module and the storage module are responsible for receiving the data transmitted by the sampling module, and performing pre-processing such as filtering, amplification, and analog-to-digital conversion. According to the preset algorithm logic, the processed data is subjected to relevant calculations, and valid information is extracted and stored. Subsequently, the information to be sent is sent by the transmission module through the wireless module.

[0056] The toroidal transformer includes an annular core 11 and a coil 12. The coil 12 is wound around the outer side of the annular core 11. The lightning arrester 10 is arranged through the annular core 11 of the toroidal transformer. Figure 5 , Figure 5 It is a connection circuit diagram of the sampling module and the calculation module. The input and output lines of the coil 12 on the toroidal mutual inductor are connected to the IN+ terminal and the 2.5V terminal of the output terminal of the TVS tube. One end of the TVS tube is grounded, and the other end is connected to the input terminal of the operational amplifier U12. The positive power supply terminal of the operational amplifier U12 is connected to the voltage Vcc, and the negative power supply terminal is grounded. The output terminal of the operational amplifier U12 is connected to the MCU control chip. A capacitor C26 is connected in series between the TVS tube and the negative phase input terminal of the operational amplifier U12, and a capacitor C30 is connected between the output terminal of the operational amplifier U12 and the MCU control chip. The capacitance of capacitor C26 is 10uF / 10V, and capacitor C26 and capacitor C30 are used to filter the sampled voltage signal. Diodes D6 and D7 are connected in series between the TVS tube and the positive phase input terminal of the operational amplifier U12, and the TVS tube, diode D6, and diode D7 play a role in protecting against overvoltage.

[0057] The input and output of the operational amplifier U12 are connected across the multiplexer U11, and the serial COM port of the multiplexer U11 is connected in series with the capacitor C9 and then connected to the normally open NO terminal and the normally closed NC terminal of the multiplexer U11, that is, the two ends of the capacitor C9 are connected across the input and output of the operational amplifier U12. The normally open NO terminal and the normally closed NC terminal of the multiplexer U11 are connected to the resistor R26 and the resistor R27 respectively, and the resistor R26 is connected in parallel with the resistor R27, and the input terminal of the multiplexer U11 is connected in series with the resistor R28 to the MCU control chip. The resistor R28 is a current limiting resistor, and the resistance values ​​of the resistor R26 and the resistor R27 are 300k and 100k respectively. The resistor R26 and the resistor R27 can achieve two different amplification results. The MCU control chip outputs GAIN to the input of the multiplexer U11. The multiplexer U11 selects the matching resistance level according to the voltage signal at both ends of the toroidal transformer, so as to select the appropriate amplification factor. At the same time, the multiplexer U11 is also used to convert the analog signal into a digital signal and send it to the MCU control chip. Capacitor C9 has a compensation function, including improving the power factor, reducing reactive power, reducing line loss, stabilizing voltage, etc.

[0058] See also Figure 4 and Figure 6 The calculation module mainly receives the sampled data through the MCU control chip. The MCU control chip includes several calculation units, which can be used to perform iterative calculations on the magnetic field strength, electromotive force, voltage and leakage current. The MCU control chip in this embodiment uses the STM32L151RCT6 model chip to calculate the relevant data. STM32L151RCT6 is a low-power control chip. STM32L151RCT6 is equipped with a high-performance ARM Cortex TM -M3 32-bit RISC core, multiple enhanced I / O and peripherals, and also equipped with standard and advanced communication interfaces. Operational amplifier U12 uses AD8541ARZ model chip, and multiplexer U11 uses TS5A3154 model chip.

[0059] See also Figure 4 and Figure 7The storage module is connected to the MCU control chip of the computing module through the SPI bus, and is used to store and retain the data and instructions generated during the collection and calculation process. The storage module mainly includes a storage chip, and the storage chip adopts the W25Q64 model chip. The W25Q64 model chip is a FLASH product based on SPI communication, with an operating voltage of 2.7 to 3.6V, an erase and write cycle of more than 100,000 times, and a data retention time of up to 20 years. Compared with ordinary serial Flash memory, the W25Q64 model chip is more flexible to use and has better performance. It is very suitable for storing sound, text and data. The chip select end CS of the W25Q64 chip is connected to Vcc in series with the resistor R7, the write end WP of the W25Q64 chip is connected to Vcc in series with the resistor R20, and the power supply end VCC of the W25Q64 chip is connected to ground in series with the capacitor C8. Resistors R7, R20 and capacitor C8 play the role of voltage stabilization protection in the circuit.

[0060] See also Figure 4 and Figure 8 The transmission module is connected to the calculation module through the serial port to transmit the collected and calculated data. The transmission module mainly includes the time switch A1 and the connector J3. The time switch A1 adopts the ET10x model chip, and the connector J3 adopts the U.FL-R-SMT-1 model coaxial connector. The ET10x chip can automatically control the opening and closing of electrical components according to the time set by the user. U.FL-R-SMT-1 can be used for cellular phones, PHS, mobile phones, wireless communication equipment, electronic measuring instruments, GPS, wireless LAN, Bluetooth and any application that requires the use of a small coaxial connector for high-frequency transmission. The RF end of the ET10x chip is connected to the U.FL-R-SMT-1 coaxial connector after being connected in series with the resistor R9. The resistor R9 is used to limit the current, protect the electronic components, adjust the working state, and improve the sensitivity and response speed of the time switch.

[0061] Experimental data

[0062] We selected a high-precision current generator to generate leakage currents of 500μA and 1000μA respectively for simulation experiments, and used a multiple iteration method to measure the leakage current. The results are shown in Table 1 below.

[0063] Output leakage current (μA) 500 1000 1 iteration 510.3 1023.9 2 iterations 508.2 1019.1 3 iterations 506.4 1015.3 4 iterations 504.9 1011.5 5 iterations 503.7 1008.3

[0064] Table 1

[0065] For the 500μA output leakage current measurement, the leakage current after the first iteration is 510.3μA. Let's first look at it from the perspective of absolute error. The absolute error after the first iteration is 510.3-500=10.3μA. It should be noted that the leakage current measurement process may be affected by other factors. The absolute error of the second iteration is expressed as 508.2-500=8.2μA. By analogy, the absolute error of the fifth iteration is expressed as 503.7-500=3.7μA, which can be reflected as the absolute error decreases with the increase in the number of iterations. In addition, from the perspective of relative error, the output formula of relative error is expressed as (measured value-true value) / true value×100%. The relative error after the first iteration is (510.3-500) / 500*100%=2.06%, while the relative error after the fifth iteration is (503.7-500) / 500*100%=0.74%.

[0066] Combined with Table 1, it can be seen that the absolute error is reduced from 10.3μA after the first iteration to 3.7μA after five iterations, and the relative error is reduced from 2.06% after the first iteration to 0.74% after five iterations. The same calculation is performed for the leakage current measurement of 1000μA. The absolute error is reduced from 23.9μA after the first iteration to 8.3μA after five iterations, and the relative error is reduced from 2.39% after the first iteration to 0.83% after five iterations. In summary, this experiment uses the iteration method to measure the leakage current of 500μA and 1000μA, effectively reducing the measurement error caused by the induced electromotive force, improving the accuracy and stability of the measurement results, and proving the superiority and effectiveness of the iteration method in leakage current measurement.

[0067] The above descriptions are only some preferred embodiments of the present disclosure and an explanation of the technical principles used. Those skilled in the art should understand that the scope of the invention involved in the embodiments of the present disclosure is not limited to the technical solutions formed by a specific combination of the above-mentioned technical features, but should also cover other technical solutions formed by any combination of the above-mentioned technical features or their equivalent features without departing from the above-mentioned inventive concept. For example, the above-mentioned features are replaced with the technical features with similar functions disclosed in the embodiments of the present disclosure (but not limited to) and the technical solutions formed.

[0068] Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments, or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A lightning arrester leakage current measurement method based on an iterative compensation method, comprising: Step 1, initialize the arrester leakage current measurement system and set the data sampling period to wake up the system regularly; Step 2, sampling the voltage at both ends of the toroidal transformer of the arrester leakage current measurement system to obtain an initial output voltage, and calculating an initial leakage current; Step 3, sampling the two ends of the toroidal transformer multiple times based on the data sampling period to obtain multiple output voltages, and then calculating the leakage current multiple times in combination with the initial leakage current; Step 4: Use the current output voltage and the previous leakage current to calculate the output leakage current through multiple iterations.

2. The method for measuring the leakage current of a lightning arrester based on an iterative compensation method according to claim 1, characterized in that: The calculation formula of the initial leakage current is: Among them, I0 represents the initial leakage current, V0 represents the initial output voltage, k represents the coefficient obtained from the calibration, Δt represents the time difference of the magnetic field change, and b represents a certain constant.

3. The method for measuring the arrester leakage current based on the iterative compensation method according to claim 2, characterized in that: The iterative calculation formula of the output leakage current is: Among them, I n Represented as the output leakage current calculated for the nth time, I n-1 Indicated as the value of the previous output leakage current, V n It is expressed as the output voltage detected for the nth time.

4. The method for measuring the leakage current of a lightning arrester based on an iterative compensation method according to claim 3, characterized in that: The two ends of the toroidal mutual inductor are sampled five times respectively according to the data sampling period, and the final output leakage current is obtained through five iterative calculations.

5. A lightning arrester leakage current measurement system based on iterative compensation method, characterized in that: The method for measuring the lightning arrester leakage current according to claims 1 to 4 comprises: A toroidal transformer and a lightning arrester, wherein the toroidal transformer comprises an annular core and a coil, wherein the coil is wound around the outside of the annular core, and the lightning arrester is arranged through the annular core; A sampling module, used to amplify and sample the output voltage collected from the input and output lines of the toroidal transformer according to a preset period; A calculation module, used for receiving the output voltage collected by the sampling module to calculate the output leakage current of the arrester; A storage module, used for effectively and quickly storing the data calculated and processed by the calculation module; The transmission module is used to transmit the output leakage current data that needs to be sent.

6. The arrester leakage current measurement system based on iterative compensation method according to claim 5, characterized in that: The calculation module includes an MCU control chip, and the MCU control chip includes a plurality of calculation units, and the calculation units are respectively used to perform iterative calculations on magnetic field intensity, electromotive force, output voltage and leakage current.

7. The arrester leakage current measurement system based on iterative compensation method according to claim 6, characterized in that: The sampling module includes an operational amplifier and a multiplexer. The input and output lines of the toroidal transformer are connected to the input end of the operational amplifier. The input and output ends of the operational amplifier are connected across the multiplexer. The multiplexer is connected to the MCU control chip via an ADC serial port.

8. The arrester leakage current measurement system based on iterative compensation method according to claim 6, characterized in that: The storage module includes a storage chip, which is connected to the MCU control chip via an SPI bus. The chip selection end and the write end of the storage chip are both connected in series with resistors, and the power supply end of the storage chip is connected in series with a capacitor and then grounded.

9. The arrester leakage current measurement system based on iterative compensation method according to claim 6, characterized in that: The transmission module includes a time-controlled switch and a connector. The time-controlled switch is connected to the MCU control chip through a serial port. The RF end of the time-controlled switch is connected to the connector after a resistor is connected in series, and data is transmitted externally through the connector.

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