An on-line monitoring device for insulation state of a lightning arrester

Abstract

The application provides an insulation state on-line monitoring device of a lightning arrester, and relates to the technical field of lightning arrester leakage monitoring.The device comprises a sensor module, at least including a voltage sensor and a current sensor, the voltage sensor obtains the voltage value on the lightning arrester through electric field coupling with the lightning arrester, and the current sensor is sleeved on the grounding wire of the lightning arrester and is used for collecting the current value leaked by the lightning arrester; a circuit protection module is connected in series with the current sensor; a data processing module is connected in communication with the voltage sensor and the current sensor respectively, is used for obtaining the insulation resistance value of the lightning arrester according to the voltage value and the current value, and determines the insulation state according to the insulation resistance value.The application can obtain the voltage value and the leaked current value of the lightning arrester by using a non-contact collection mode, reduces the influence of interference signals on the voltage value and the current value, and provides technical support for obtaining the accurate insulation state of the lightning arrester.

Description

Technical Field

[0001] This application relates to the field of leakage current monitoring technology for surge arresters, and more particularly to an online monitoring device for the insulation status of surge arresters. Background Technology

[0002] Current methods for monitoring the insulation status of surge arresters mainly fall into two categories: online monitoring and offline detection. Online monitoring methods include leakage current monitoring, infrared thermal imaging technology, ultrasonic or high-frequency partial discharge detection, online monitoring system integration, and temperature monitoring. Leakage current monitoring is further divided into the total current method and the resistive current method. The total current method determines the insulation status by monitoring the total leakage current, while the resistive current method assesses the degree of varistor degradation by separating the resistive component. Infrared thermal imaging technology detects surface temperature distribution and identifies localized overheating problems. Partial discharge detection locates internal defects by capturing ultrasonic or high-frequency signals. Online monitoring systems combine multi-parameter acquisition and utilize big data or AI algorithms to achieve intelligent early warning. Temperature monitoring directly monitors internal temperature changes through built-in sensors.

[0003] The aforementioned offline testing methods include insulation resistance testing, DC reference voltage and leakage current testing, power frequency reference voltage testing, dielectric loss tangent testing, and partial discharge testing. Insulation resistance testing uses a megohmmeter to measure insulation resistance; a low value indicates moisture or degradation. The DC reference voltage test determines the aging condition of the valve plate by measuring the reference voltage and leakage current. The power frequency reference voltage test measures the volt-ampere characteristics to verify valve plate performance. The dielectric loss tangent test assesses the loss of the insulation material. The partial discharge test applies high voltage offline to detect the discharge quantity and defect location.

[0004] However, these methods still have certain limitations in practical applications. In online monitoring, leakage current is easily affected by factors such as power grid harmonics and ambient temperature and humidity, and the accuracy of resistive current separation is limited. Infrared thermal imaging can only detect surface temperature and cannot reflect deep internal defects, and it is easily affected by environmental conditions. Partial discharge detection is susceptible to electromagnetic interference, and may miss or falsely report when the signal is weak. Online monitoring systems rely on the long-term stability of sensors, have high maintenance costs, and have strict requirements for communication networks. Offline detection requires power outages, affecting power supply continuity, and some high-voltage tests may cause cumulative damage to equipment. The test conditions differ from actual operating conditions, which may lead to deviations in results. Dielectric loss testing has low sensitivity for metal oxide surge arresters and is easily affected by ambient humidity. Partial discharge testing equipment is complex, time-consuming to operate, and difficult to locate small defects.

[0005] Overall, existing monitoring methods all have certain shortcomings. Therefore, there is an urgent need to develop a new monitoring device that meets practical needs in order to improve the accuracy and reliability of detection. Utility Model Content

[0006] To address the aforementioned technical problems, this application provides an online monitoring device for the insulation status of surge arresters, thereby solving the problem of low accuracy in surge arrester monitoring results. The technical solution is as follows:

[0007] This application provides an online monitoring device for the insulation status of a surge arrester, comprising:

[0008] The sensor module includes at least a voltage sensor and a current sensor. The voltage sensor obtains the voltage value on the surge arrester by electric field coupling with the surge arrester, and the current sensor is sleeved on the grounding wire of the surge arrester to collect the leakage current value of the surge arrester.

[0009] The circuit protection module is connected in series with the current sensor;

[0010] The data processing module is communicatively connected to the voltage sensor and the current sensor, respectively, and is used to obtain the insulation resistance value of the surge arrester based on the voltage value and the current value, and to determine the insulation status based on the insulation resistance value.

[0011] In one possible implementation, the voltage sensor includes a high-voltage electrode, a sensing electrode, and a signal processing chip;

[0012] The high-voltage electrode is positioned close to the high-voltage end of the surge arrester, forming a coupling capacitor with the surge arrester;

[0013] The induction electrode is positioned close to the high-voltage electrode and spaced at a predetermined distance from the high-voltage end of the surge arrester, forming a ground capacitance with the high-voltage electrode;

[0014] The signal processing chip obtains the voltage value based on the coupling capacitor and the capacitance to ground.

[0015] In one possible implementation, the voltage value is calculated using the following formula:

[0016]

[0017] Among them, U out U represents the voltage value output by the voltage sensor. MOA This indicates the voltage value on the surge arrester, C1 represents the coupling capacitor, C2 represents the capacitance to ground, and C... in This represents the capacitance input to the voltage sensor.

[0018] In one possible implementation, the current sensor includes an annular housing, a magnetic core, and a magnetic sensing element, wherein the magnetic core and the magnetic sensing element are combined to form a complete ring and are nested within the annular housing;

[0019] A first coil winding and a second coil winding are wound at intervals on the magnetic core, and the direction of the magnetic flux density generated by the second coil winding is opposite to the direction of the magnetic flux density of the first coil winding.

[0020] The input terminal of the first coil winding is connected to the grounding wire of the surge arrester;

[0021] A second amplifier is provided at the input end of the second coil winding, and the second coil winding is connected to the magnetic induction element through the second amplifier. A data acquisition unit is provided at the output end of the second coil winding, and the data acquisition unit is used to acquire the compensation current on the second coil winding to obtain the leakage current value of the surge arrester.

[0022] In one possible implementation, the acquisition unit includes a measuring resistor and an ammeter;

[0023] One end of the measuring resistor is connected to the output end of the second coil winding, and the other end of the measuring resistor is connected to the ammeter. The end of the ammeter away from the measuring resistor is grounded. The signal output end of the ammeter is communicatively connected to the data processing module. The ammeter is used to measure the current value flowing through the measuring resistor to obtain the leakage current value of the surge arrester.

[0024] In one possible implementation, a thermal radiation module is also included, which is positioned close to the surge arrester and is used to collect the temperature of the surge arrester.

[0025] In one possible implementation, the circuit protection module includes a thermistor and an electrical switch, with one end of the thermistor connected to the current sensor and the other end connected to the electrical switch, and the end of the electrical switch away from the thermistor grounded.

[0026] In one possible implementation, the data processing module is also communicatively connected to the thermal radiation module, and the data processing module controls the closing of the electrical switch based on at least one of the voltage value, current value, and temperature value.

[0027] In one possible implementation, a power supply module is also included, wherein the power supply terminal of the power supply module is provided with an NPN transistor, the base of the NPN transistor is connected to the grounding wire of the surge arrester, the collector of the NPN transistor is connected to the power supply module, and the emitter of the NPN transistor is connected to the data processing module.

[0028] In one possible implementation, a wireless communication module is also included, through which the data processing module interacts with external devices.

[0029] By employing the above technical solution, the online monitoring device for the insulation status of surge arresters provided in this application embodiment first uses a voltage sensor, a current sensor, and a thermal radiation module to collect the voltage value, leakage current value, and temperature value of the surge arrester, respectively. Then, when leakage current is indeed present in the surge arrester, the power module wakes up the data processing module. The data processing module calculates the insulation resistance value of the surge arrester based on the voltage and current values, and then determines the insulation status of the surge arrester based on the insulation resistance value. After obtaining the insulation status of the surge arrester, the obtained insulation status is also verified by the temperature value of the surge arrester. If the verification passes, the final insulation status of the surge arrester is obtained, ensuring the accuracy of the final obtained insulation status of the surge arrester. It can be seen that the technical solution provided in this application embodiment can achieve the following technical effects.

[0030] (1) In this embodiment, neither the voltage sensor nor the current sensor is directly connected to the surge arrester. Instead, the voltage value and leakage current value of the surge arrester are collected through a non-contact measurement method to ensure that the voltage sensor and the current sensor operate stably in complex electromagnetic fields and improve the environmental adaptability of the monitoring device of this application.

[0031] (2) After obtaining the insulation status of the surge arrester through the voltage value and leakage current value of the surge arrester, the data processing module will also obtain an insulation status through the temperature collected by the thermal radiation module, and determine whether the two insulation statuses are consistent. If they are inconsistent, the voltage value and leakage current value of the surge arrester will be obtained again to verify whether the obtained insulation status of the surge arrester is consistent with the actual situation, thereby improving the accuracy of the final obtained insulation status of the surge arrester.

[0032] (3) When there is leakage current in the surge arrester, the power supply module supplies power to the data processing module to wake up the data processing module to perform the corresponding work, thereby obtaining the insulation state of the surge arrester; if there is no leakage current in the surge arrester, the power supply module stops supplying power to the data processing module, and the data processing module enters the sleep mode, so as to achieve the purpose of energy saving and ensure the long-term operation of the device of this application. Attached Figure Description

[0033] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the description of the embodiments of this application will be briefly introduced below. In the drawings:

[0034] Figure 1 This is an overall structural block diagram of an online insulation status monitoring device for surge arresters provided in an embodiment of this application;

[0035] Figure 2 This is a structural block diagram of the voltage sensor provided in the embodiments of this application;

[0036] Figure 3This is an overall structural diagram of the current sensor provided in the embodiments of this application;

[0037] Figure 4 This is a structural block diagram of the current sensor provided in the embodiments of this application.

[0038] Explanation of reference numerals in the attached drawings: 10, sensor module; 11, voltage sensor; 12, current sensor; 121, housing; 122, magnetic core; 123, magnetic induction element; 124, first coil winding; 125, second coil winding; 126, acquisition unit; 20, circuit protection module; 30, thermal radiation module; 40, data processing module; 50, power supply module; 60, wireless communication module; 70, surge arrester. Detailed Implementation

[0039] Exemplary embodiments of the present application will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present application are shown in the drawings, it should be understood that the present application may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this application will be thorough and complete, and will fully convey the scope of the present application to those skilled in the art.

[0040] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such use can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the term "comprising" and its variations should be interpreted as open-ended terms meaning "including but not limited to."

[0041] This application provides an online monitoring device for the insulation status of a surge arrester, referring to... Figure 1 The device includes a sensor module 10, a circuit protection module 20, a thermal radiation module 30, a data processing module 40, a power supply module 50, and a wireless communication module 60. The data processing module 40, as the core of the device, is used to receive data from each module and control the stable operation of each module.

[0042] The sensor module 10 can be composed of a voltage sensor 11 and a current sensor 12, or it can be a sensor group composed of multiple voltage sensors 11 and multiple current sensors 12. The voltage sensor 11 and the current sensor 12 in the sensor module 10 are set independently.

[0043] Reference Figure 2The voltage sensor 11 includes a high-voltage electrode, a sensing electrode, and a signal processing chip. The high-voltage electrode is made of a metal material, such as copper or aluminum, and is plate-shaped or ring-shaped, with an insulating layer on its surface, composed of epoxy resin or ceramic. The high-voltage electrode is positioned close to the high-voltage terminal of the surge arrester 70 and maintains a safe insulating distance from the arrester 70. This safe insulating distance can be calculated through a limited number of experiments. The high-voltage terminal of the surge arrester 70 refers to its connection terminal directly connected to the power system. The high-voltage terminal of the surge arrester 70 is connected to the high potential of the power system via a conductor and withstands the operating voltage of the power system. The sensing electrode is also made of a metal material, such as copper, and is block-shaped with an insulating and anti-corrosion layer on its surface, reducing environmental interference and the probability of corrosion, thus increasing its service life. The sensing electrode is positioned close to the high-voltage electrode and at a preset distance from the high-voltage terminal of the surge arrester 70. This preset distance is set according to the actual installation scenario. The signal processing chip can be an MCU chip or a DSP chip. The input terminal of the signal processing chip is connected to the signal output terminal of the sensing electrode. A first amplifier and an analog-to-digital converter are also provided on the signal output terminal of the sensing electrode, which are represented by A1 and ADC respectively.

[0044] In practical applications, the high-voltage electrode faces the high-voltage terminal of the surge arrester 70, forming a coupling electrode with the surge arrester 70. The induction electrode forms a ground capacitance with the high-voltage electrode. The high-voltage electrode forms an electric field connection with the high-voltage terminal of the surge arrester 70 through capacitive coupling. The induction electrode senses changes in the electric field and outputs a low-voltage signal proportional to the high-voltage terminal of the surge arrester 70. The low-voltage signal is processed sequentially by the first amplifier A1 and the analog-to-digital converter ADC to obtain a voltage value, which is then transmitted to the signal processing chip. This voltage value is also called the voltage value output by the voltage sensor 11, denoted by U. out The signal processing chip, based on a pre-stored calculation formula, uses the coupling capacitor, the capacitance to ground, the capacitance input to voltage sensor 11, and the voltage value U output by voltage sensor 11. out The voltage value on surge arrester 70 is calculated using the following formula:

[0045]

[0046] Among them, U out U represents the voltage value output by voltage sensor 11. MOA This indicates the voltage value on surge arrester 70, C1 represents the coupling capacitor, C2 represents the capacitance to ground, and C... in C represents the capacitance input to voltage sensor 11. in It is the capacitance formed by the voltage sensor 11 itself, which is obtained by the manufacturer after measurement during production.

[0047] The aforementioned coupling capacitor C1 and ground capacitor C2 need to be calculated by the signal processing chip or by an external device and then input into the signal processing chip. External devices include smart devices such as mobile phones, tablets, and computers.

[0048] Specifically, the formula for calculating the coupling capacitance C1 is as follows:

[0049]

[0050] Where ε0 represents the vacuum permittivity, ε r The relative permittivity of the insulating layer of the high-voltage electrode is indicated. For example, the relative permittivity of the insulating layer formed by epoxy resin is between 3 and 5. S represents the effective area of ​​the high-voltage electrode, and d represents the safe insulation distance between the high-voltage electrode and the high-voltage terminal of the surge arrester 70.

[0051] The formula for calculating the capacitance to ground C2 is the same as that for calculating the coupling capacitance C1. The difference is that d in the formula for calculating the capacitance to ground C2 represents the vertical distance between the sensing electrode and the ground. Therefore, the calculation of the capacitance to ground C2 will not be described in detail in this embodiment.

[0052] Therefore, the signal processing chip can determine the capacitance based on the coupling capacitor C1, the ground capacitor C2, and the capacitance C input from the voltage sensor 11. in and the voltage value U output by voltage sensor 11 out The voltage value U on surge arrester 70 was calculated. MOA .

[0053] Reference Figure 3 and Figure 4 The current sensor 12 includes an annular housing 121 and a magnetic core 122 and a magnetic induction element 123 disposed inside the annular housing 121. Specifically, the magnetic core 122 is C-shaped, and the magnetic induction element 123 is an arc-shaped soft magnetic sheet. The magnetic induction element 123 and the magnetic core 122 are combined to form a complete ring and nested inside the annular housing 121. The annular housing 121 is fitted onto the grounding wire of the surge arrester 70, and the outer surface of the annular housing 121 is covered with an insulating layer.

[0054] A first coil winding 124 and a second coil winding 125 are wound at intervals on a magnetic core 122, with the direction of the magnetic flux density generated by the second coil winding 125 opposite to that of the first coil winding 124. Specifically, the input terminal of the first coil winding 124 is connected to the grounding wire of the surge arrester 70. A second amplifier is provided on the input terminal of the second coil winding 125 and is connected to the magnetic induction element 123 through the second amplifier, which is denoted as A2. A data acquisition unit 126 is provided on the output terminal of the second coil winding 125. The data acquisition unit 126 includes a measuring resistor and an ammeter, denoted as R1 and PA, respectively. One end of the measuring resistor R1 is connected to the output terminal of the second coil winding 125, and the other end of the measuring resistor R1 is connected to the ammeter PA. The end of the ammeter PA away from the measuring resistor R1 is grounded, and the signal output terminal of the ammeter PA is communicatively connected to the data processing module 40. The ammeter PA is used to measure the current flowing through the measuring resistor R1.

[0055] In practical applications, when the DC signal on the grounding wire of the surge arrester 70 passes through the first coil winding 124, a magnetic field is generated in the magnetic core 122. The magnetic flux in the magnetic field is concentrated on the magnetic induction element 123. The voltage signal generated by the magnetic induction element 123 is amplified by the second amplifier A2 and then applied to the second coil winding 125 to generate a reverse compensation current. The magnetic flux generated by the compensation current is opposite in direction to the magnetic flux generated by the DC signal on the grounding wire of the surge arrester 70. When the two achieve magnetic balance, the magnetic flux of the magnetic core 122 is zero. The compensation current on the second coil winding 125 is collected by the ammeter PA in the acquisition unit 126 to obtain the leakage current value of the surge arrester 70.

[0056] Therefore, it can be seen that neither the voltage sensor 11 nor the current sensor 12 in this embodiment are directly connected to the surge arrester 70. Instead, the voltage value and leakage current value of the surge arrester 70 are collected through a non-contact measurement method to ensure that the voltage sensor 11 and the current sensor 12 operate stably in complex electromagnetic fields and improve the environmental adaptability of the monitoring device of this application.

[0057] Reference Figure 1 The circuit protection module 20 is connected in series with the current sensor 12. The circuit protection module 20 includes a thermistor and an electric switch, denoted by R0 and K1, respectively. One end of the thermistor R0 is connected to the output terminal of the current sensor 12, specifically to the grounded end of the measuring resistor R1. The other end of the thermistor R0 is connected to one end of the electric switch K1, and the other end of the electric switch K1 is grounded. The control terminal of the electric switch K1 is controlled by the data processing module 40.

[0058] The thermal radiation module 30 can be any one of a thermopile sensor, a quantum infrared sensor, or a pyroelectric sensor. A thermopile sensor, composed of multiple thermocouples connected in series, converts infrared radiation into a temperature difference and then into a voltage signal. It is small in size and can be integrated into various space-constrained housings. A quantum infrared sensor can be a photodiode or an infrared detector. Quantum infrared sensors have a fast response speed and can quickly capture temperature changes in the surge arrester 70. A pyroelectric sensor utilizes the temperature change of a pyroelectric material to generate surface charge, thereby measuring the temperature change of the surge arrester 70. This embodiment preferably uses a thermopile sensor, which is housed within a high-temperature resistant housing. Figure 1 Not shown in the diagram, the housing is located close to the surge arrester 70, and the housing has an opening on the side facing the surge arrester 70. The infrared radiation sensing end of the thermopile sensor collects the temperature value of the surge arrester 70 in real time through this opening.

[0059] The data processing module 40 is an MCU chip, which is integrated on a circuit board. The circuit board is housed in a high-temperature and corrosion-resistant housing. Figure 1 The image is not shown in the image. The data processing module 40 is communicatively connected to the voltage sensor 11, the current sensor 12, and the thermal radiation module 30, respectively. Figure 1 This connection method is indicated by dashed lines. Specifically, the data processing module 40 is communicatively connected to the signal processing chip, the ammeter PA, and the thermopile sensor to acquire the voltage, leakage current, and temperature values ​​of the surge arrester 70, respectively.

[0060] The data processing module 40 stores a calculation formula in advance. This formula is used to calculate the insulation resistance value of the surge arrester 70 based on the voltage and current values. The calculation formula is as follows:

[0061]

[0062] in, U represents the insulation resistance value of surge arrester 70. MOA I and I represent the voltage and leakage current values ​​on the surge arrester 70, respectively, and θ represents the phase difference between the voltage and current values.

[0063] After obtaining the insulation resistance value, the data processing module 40 determines the resistance value range into which the insulation resistance value falls, and uses the insulation state corresponding to the resistance value range as the insulation state of the surge arrester 70. In this embodiment, each resistance value range and the corresponding insulation state are preset.

[0064] In this embodiment, after the data processing module 40 obtains the insulation status of the surge arrester 70, it acquires the temperature value of the surge arrester 70. Each temperature value also corresponds to an insulation status. The module then determines whether the insulation status calculated by the voltage and current values ​​is consistent with the insulation status obtained by matching the temperature of the surge arrester 70. If they are inconsistent, the module reacquires the voltage and leakage current values ​​of the surge arrester 70 to verify whether the obtained insulation status of the surge arrester 70 conforms to the actual situation and improves the accuracy of monitoring.

[0065] In addition, the data processing module 40 is also connected to the electrical switch K1 in the circuit protection module 20. Specifically, it is connected to the controlled end of the electrical switch K1. When the data processing module 40 receives any one of the voltage value, leakage current value, and temperature value of the surge arrester 70 that exceeds its corresponding preset value, the data processing module 40 controls the electrical switch K1 to close, thereby connecting the thermistor R0 to the circuit where the current sensor 12 is located, increasing the resistance value of the circuit and thus protecting the current sensor 12.

[0066] The power module 50 can extract electrical energy from the power line in a non-electrical connection manner based on the principle of electromagnetic induction, such as by drawing energy from a current transformer (CT). The power module 50 can also be powered by solar energy. The power module 50 and the data processing module 40 are integrated on the same circuit board. An NPN transistor, denoted as K2, is installed at the power supply terminal of the power module 50. The base of the NPN transistor K2 is connected to the grounding wire of the surge arrester 70, the collector of the NPN transistor K2 is connected to the power module 50, and the emitter of the NPN transistor K2 is connected to the data processing module 40. A low-dropout voltage regulator, denoted as LDO, is also installed on the line connecting the NPN transistor K2 and the data processing module 40. The LDO can convert the fluctuating input voltage into the voltage required by the data processing module 40.

[0067] In practical applications, when leakage current flows through the grounding wire of surge arrester 70, the base receives a high-level signal. At this time, the collector and emitter of NPN transistor K2 are turned on, and power supply module 50 supplies power to data processing module 40. That is, when there is leakage current in surge arrester 70, power supply module 50 supplies power to data processing module 40 to wake up data processing module 40 to perform corresponding work and obtain the insulation state of surge arrester 70; if there is no leakage current in surge arrester 70, the base receives a low-level signal. At this time, the collector and emitter of NPN transistor K2 are turned off, power supply module 50 stops supplying power to data processing module 40, and data processing module 40 enters sleep mode to achieve energy saving and ensure the long-term operation of the device of this application.

[0068] The wireless communication module 60 can be any one of a WIFI module, Bluetooth module, and 4G / 5G communication module. The wireless communication module 60 is also integrated with the data processing module 40 on the same circuit board. The data processing module 40 sends information such as the voltage value, leakage current value, temperature, insulation resistance, and insulation status of the surge arrester 70 to an external device through the wireless communication module 60, so that the management personnel can remotely view the working status of the surge arrester 70, thereby facilitating its subsequent maintenance and management.

[0069] In summary, the implementation principle of the online monitoring device for the insulation status of a surge arrester provided in this application embodiment is as follows: First, the voltage sensor 11, current sensor 12, and thermal radiation module 30 respectively collect the voltage value, leakage current value, and temperature value on the surge arrester 70. Then, when leakage current is indeed present in the surge arrester 70, the power supply module 50 wakes up the data processing module 40. The data processing module 40 calculates the insulation resistance value of the surge arrester 70 based on the voltage and current values, and then determines the insulation status of the surge arrester 70 based on the insulation resistance value. After obtaining the insulation status of the surge arrester 70, the obtained insulation status is also verified by the temperature value of the surge arrester 70. After the verification is passed, the final insulation status of the surge arrester 70 is obtained, ensuring the accuracy of the final obtained insulation status of the surge arrester 70.

[0070] The above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit it. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that within the spirit and principles of this application, modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein; and these modifications or substitutions do not cause the corresponding technical solutions to leave the protection scope of this application.

Claims

1. An online monitoring device for the insulation status of a surge arrester, characterized in that, include: The sensor module (10) includes at least a voltage sensor (11) and a current sensor (12); wherein the voltage sensor (11) includes a high-voltage electrode, a sensing electrode, and a signal processing chip; the high-voltage electrode is disposed near the high-voltage end of the surge arrester (70) and forms a coupling capacitor with the surge arrester (70); the sensing electrode is disposed near the high-voltage electrode and spaced at a preset distance from the high-voltage end of the surge arrester (70) and forms a ground capacitance with the high-voltage electrode; the signal processing chip obtains the voltage value based on the coupling capacitor and the ground capacitance; the current sensor (12) is sleeved on the grounding wire of the surge arrester (70) and is used to collect the leakage current value of the surge arrester (70); The circuit protection module (20) is connected in series with the current sensor (12); The data processing module (40) is communicatively connected to the voltage sensor (11) and the current sensor (12) respectively, and is used to obtain the insulation resistance value of the surge arrester (70) based on the voltage value and the current value, and to determine the insulation status based on the insulation resistance value.

2. The online monitoring device for the insulation status of a surge arrester according to claim 1, characterized in that, The voltage value is calculated using the following formula: ， in, This indicates the voltage value output by the voltage sensor (11). This indicates the voltage value on the surge arrester (70). Indicates coupling capacitor. Indicates capacitance to ground. This represents the capacitance input to the voltage sensor (11).

3. The online monitoring device for the insulation status of a surge arrester according to claim 1, characterized in that, The current sensor (12) includes an annular housing (121), a magnetic core (122) and a magnetic sensing element (123). The magnetic core (122) and the magnetic sensing element (123) are combined to form a complete ring and are nested inside the annular housing (121). A first coil winding (124) and a second coil winding (125) are wound at intervals on the magnetic core (122), and the direction of the magnetic flux density generated by the second coil winding (125) is opposite to the direction of the magnetic flux density of the first coil winding (124). The input terminal of the first coil winding (124) is connected to the grounding wire of the surge arrester (70); A second amplifier is provided on the input end of the second coil winding (125), and the second coil winding (125) is connected to the magnetic induction element (123) through the second amplifier. A collection unit (126) is provided on the output end of the second coil winding (125), and the collection unit (126) is used to collect the compensation current on the second coil winding (125) to obtain the leakage current value of the surge arrester (70).

4. The online monitoring device for the insulation status of a surge arrester according to claim 3, characterized in that, The acquisition unit (126) includes a resistance meter and an ammeter; One end of the measuring resistor is connected to the output end of the second coil winding (125), and the other end of the measuring resistor is connected to the ammeter. The end of the ammeter away from the measuring resistor is grounded. The signal output end of the ammeter is connected to the data processing module (40) for communication. The ammeter is used to measure the current value flowing through the measuring resistor to obtain the leakage current value of the surge arrester (70).

5. The online monitoring device for the insulation status of a surge arrester according to claim 1, characterized in that, It also includes a thermal radiation module (30) which is located close to the surge arrester (70) and is used to collect the temperature of the surge arrester (70).

6. The online monitoring device for the insulation status of a surge arrester according to claim 5, characterized in that, The circuit protection module (20) includes a thermistor and an electric switch. One end of the thermistor is connected to the current sensor (12), and the other end is connected to the electric switch. The end of the electric switch away from the thermistor is grounded.

7. The online monitoring device for the insulation status of a surge arrester according to claim 6, characterized in that, The data processing module (40) is also communicatively connected to the thermal radiation module (30), and the data processing module (40) controls the closing of the electric switch according to at least one of the voltage value, current value and temperature value.

8. The online monitoring device for the insulation status of a surge arrester according to claim 1, characterized in that, It also includes a power module (50), the power supply terminal of which is provided with an NPN transistor, the base of which is connected to the grounding wire of the surge arrester (70), the collector of which is connected to the power module (50), and the emitter of which is connected to the data processing module (40).

9. The online monitoring device for the insulation status of a surge arrester according to claim 1, characterized in that, It also includes a wireless communication module (60), through which the data processing module (40) interacts with external devices.

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