Lightning arrester on-line monitoring system based on self power supply

Abstract

The invention relates to the technical field of power equipment monitoring, in particular to a lightning arrester on-line monitoring system based on self power supply. The system obtains electric energy from leakage current of a lightning arrester through an electricity taking module, realizes self-powered operation of the system, and comprises the electricity taking module, a power management module, a lightning stroke counting module, a leakage current acquisition module, a temperature monitoring module, a display and communication module and an SOC control module. According to the system, the temperature capacity is adopted as an aging state evaluation index of the lightning arrester, the temperature of the lightning arrester and the environment temperature are collected in real time, the corrected temperature capacity is calculated in combination with leakage current and lightning current correction coefficients and dynamic weight adjustment, and accurate aging state judgment is achieved. The system has the functions of periodic acquisition, event trigger detection, data correction, wireless communication and local display, supports long-term online monitoring and remote alarm, and effectively improves the accuracy and reliability of lightning arrester state monitoring.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of power equipment monitoring, and particularly relates to a lightning arrester online monitoring system based on self-power supply. BACKGROUND

[0002] As a key equipment for overvoltage protection of power systems, the aging state of lightning arresters during long-term operation is directly related to the safety of power grids. Traditional monitoring methods rely on manual periodic inspection or external power supply online monitoring devices, which have challenges such as insufficient real-time performance, strong power supply dependence, and limited data accuracy. Especially in remote areas or passive scenarios, power supply difficulties make it difficult for monitoring systems to operate stably for a long time.

[0003] The existing technology for evaluating the aging state of lightning arresters relies on a single parameter such as leakage current or lightning strike times, lacks a comprehensive judgment method with multiple factors, and is difficult to fully reflect the cumulative aging effect. Therefore, there is an urgent need for an online monitoring system that can be self-powered, real-time monitored, and multi-parameter fusion judged to improve the reliability and accuracy of lightning arrester state monitoring. SUMMARY

[0004] The present application aims to solve the problems in the background art and proposes a lightning arrester online monitoring system based on self-power supply.

[0005] The technical solution of the present application is a lightning arrester online monitoring system based on self-power supply, which comprises: A power taking module for obtaining electrical energy from the leakage current of the lightning arrester; A power management module connected to the power taking module for converting the electrical energy obtained by the power taking module into a stable system voltage and supplying power to other modules of the system; A lightning strike counting module for detecting and recording the number of lightning strike events suffered by the lightning arrester; A leakage current acquisition module for acquiring the leakage current value of the lightning arrester; A temperature monitoring module for real-time acquisition of the body temperature and ambient temperature of the lightning arrester; A display and communication module for local display of monitoring data and sending data to a remote monitoring center; An SOC control module connected to the power management module, the lightning strike counting module, the leakage current acquisition module, the temperature monitoring module, and the display and communication module; The SOC control module is configured to: Calculate the temperature capacity increment based on the body temperature and ambient temperature of the lightning arrester acquired by the temperature monitoring module; Obtain the leakage current correction coefficient determined by the current leakage current value and the lightning current correction coefficient determined by the lightning strike event and the lightning current value; The influence factor is calculated by using the leakage current correction coefficient and the lightning current correction coefficient, combining the dynamically adjusted leakage current weight and lightning current weight, and correcting the temperature capacity increment. The cumulative temperature capacity is obtained by accumulating the corrected temperature capacity increment, and the aging state of the surge arrester is evaluated according to the cumulative temperature capacity, and an alarm is triggered when the threshold is exceeded.

[0006] Preferably, the power taking module includes a voltage-dependent resistor and a power taking bypass; The power taking bypass is composed of a plurality of resistors in series; When the surge arrester is in normal operation, the voltage-dependent resistor is in a high resistance state, and the leakage current flows through the power taking bypass to provide power for the system.

[0007] Preferably, the power management module has a plurality of tantalum capacitors integrated inside, which are used to provide instantaneous energy when the system performs wireless data transmission and leakage current collection.

[0008] Preferably, the lightning stroke counting module uses an optical coupler for lightning stroke detection; When the system is in normal operation, the optical coupler outputs a high level; when lightning occurs, the optical coupler is turned on and outputs a low level to the SOC control module, and the SOC control module counts the number of lightning actions after detecting the falling edge signal.

[0009] Preferably, the leakage current collection module includes a solid state relay, an operational amplifier and a signal conditioning circuit; The SOC control module controls the conduction and shutdown of the solid state relay to switch the leakage current collection state and the power taking state of the system; In the leakage current collection state, the operational amplifier works, and the collected leakage current signal is processed by the signal conditioning circuit and then sent to the analog-to-digital converter of the SOC control module.

[0010] Preferably, the display and communication module includes a fault code display screen and a wireless communication module; The fault code display screen is used for local display of the leakage current value, the number of lightning events, the cumulative temperature capacity and the system operation state; The wireless communication module is used to send monitoring data and alarm information to a remote monitoring center.

[0011] Preferably, the SOC control module periodically wakes up the system through its internal timer, controls the temperature monitoring module and the leakage current collection module to sequentially perform data collection tasks, and controls the system to enter a sleep state during the non-collection period.

[0012] Preferably, the SOC control module calculates the temperature capacity for evaluating the aging state of the surge arrester in the following way: The body temperature and the ambient temperature of the surge arrester at a plurality of consecutive time points are collected, and the temperature capacity increment at adjacent time points is calculated ; wherein, is the temperature of the arrester at time t i ; is the ambient temperature at time t i ; According to the current leakage current value, the preset leakage current level and correction coefficient table is inquired to determine the corresponding leakage current correction coefficient λ ci ; According to whether a lightning stroke event occurs and a lightning current value, the preset lightning current level and correction coefficient table is inquired to determine the corresponding lightning current correction coefficient λ Ii ; Based on the leakage current correction coefficient and the lightning current correction coefficient, in combination with the dynamically adjusted leakage current weight WC i and the lightning current weight WI i , the influence factor at the current time is calculated ; The temperature capacity increment is corrected by using the influence factor to obtain the corrected temperature capacity : ; The corrected temperature capacity increment is added to the total temperature capacity, that is, ; wherein, n is the total number of set collection times; The cumulative temperature capacity TC is compared with a preset threshold value in real time, when TC exceeds the threshold value, it is determined that the aging state of the arrester reaches a critical point, alarm information is immediately displayed on a local code display screen and alarm data is sent to a remote monitoring center through a wireless communication module.

[0013] Preferably, the corresponding leakage current correction coefficient is determined according to the current leakage current value, comprising: dividing the monitored leakage current value into a plurality of preset leakage current intervals, each leakage current interval corresponding to a leakage current correction coefficient; wherein the leakage current interval is divided in a nonlinear manner, the larger the leakage current value, the smaller the corresponding interval range; The corresponding lightning current correction coefficient is determined according to whether a lightning stroke event occurs and a lightning current value, comprising: dividing the monitored lightning current impact value into a plurality of preset lightning current intervals, each lightning current interval corresponding to a lightning current correction coefficient; wherein the larger the lightning current value, the larger the corresponding lightning current correction coefficient.

[0014] Compared with the prior art, the above technical scheme of the present application has the following beneficial technical effects: The application designs a lightning arrester online monitoring system based on self-power supply, directly obtains electric energy from the leakage current of the lightning arrester through the self-power supply design, breaks away from the dependence on external power supply, and realizes all-weather uninterrupted online monitoring; the system adopts multiple modules to work cooperatively, combines high-precision data acquisition and dynamic correction methods, and significantly improves the accuracy and reliability of the judgment on the aging state of the lightning arrester; by introducing temperature capacity as a core evaluation index and based on the real-time data of the leakage current and lightning current, the temperature capacity is weighted and corrected, so that the actual operation state and cumulative aging effect of the lightning arrester can be more comprehensively reflected; the system has the functions of low-power operation, event-triggered acquisition, remote communication and local display, supports long-term stable work, and can timely send out early warning, effectively preventing the power system failure caused by the aging of the lightning arrester. BRIEF DESCRIPTION OF DRAWINGS

[0015] Figure 1 A hardware architecture schematic diagram of the lightning arrester online monitoring system based on self-power supply is provided. DETAILED DESCRIPTION

[0016] In embodiment one, the hardware structure of the lightning arrester online monitoring system based on self-power supply is as shown in the figure, which comprises a power taking bypass, a voltage-dependent resistor, a lightning stroke counting module, a solid-state relay module, an operational amplifier, a signal conditioning circuit, a SOC (system on chip) control module, a power management module, a fault code display screen, a temperature monitoring module and a wireless communication module. Figure 1

[0017] The above system mainly comprises the following modules: The power taking module is composed of a voltage-dependent resistor (1mA voltage is 620V) and a power taking bypass (6 12kΩ / 2W resistors in series), when the lightning arrester normally operates, the voltage-dependent resistor is in a high resistance state, and the impedance is much larger than that of the power taking bypass, so that the leakage current flows to the grounding end through the bypass, thereby providing electric energy for the system; The power management module converts the voltage of the power taking bypass into 5V system voltage, and internally integrates 5 1000μF tantalum capacitors, which are used to provide instantaneous energy when the wireless transmission and leakage current acquisition are performed, so as to prevent the system reset caused by voltage drop; The lightning stroke counting module adopts an optical coupler to realize lightning stroke detection, and outputs a high level in normal state; when lightning strikes, the optical coupler is turned on, and outputs a low level, and the SOC control module detects the falling edge and accumulatively counts the action times; The leakage current acquisition module comprises a solid-state relay, an operational amplifier and a signal conditioning circuit; the SOC controls the solid-state relay to be turned on / off, so as to switch the leakage current acquisition state: when the leakage current is acquired, the power taking is suspended, and the leakage current is accurately measured; after the acquisition is completed, the relay is turned off to reduce the power consumption; the output signal of the operational amplifier is sent to the ADC module of the SOC after being conditioned, and through software filtering, average value taking and standard source calibration, the accurate leakage current value is obtained;​ Temperature monitoring module: built-in temperature sensor, real-time acquisition of arrester temperature (denoted as TMOV) and environmental temperature (denoted as TEV), for calculating temperature capacity and correction; Display and communication module: adopt ultra-low power code display screen, bidirectional connection with SOC control module, display monitoring data; wireless communication module is responsible for sending data to remote monitoring center; SOC control module: as the core of the system, integrate timer, analog-to-digital converter (ADC) and communication interface; through the timer (such as 500ms period) to wake up the system, collect temperature and leakage current; trigger the collection of lightning current when lightning strikes; realize data storage, processing and communication control.

[0018] In embodiment two, the self-powered arrester online monitoring system proposed by the application further includes a temperature capacity calculation and correction method, and the implementation process is as follows: The system evaluates the aging state of the arrester through "temperature capacity", and the temperature capacity TC is defined as the integral of the difference between the operating temperature and the environmental temperature and the time, that is: ; Wherein, TMOV is the temperature of the arrester; TEV is the environmental temperature; TC is the temperature capacity (abbreviated as TC).

[0019] Specifically: A1, set n collection times: t1, t2, …, t i , …, t n , the temperature and environmental temperature of the arrester corresponding to each collection time; Denoted as ; Calculate the temperature capacity increment of any adjacent time: ; Wherein, is the temperature capacity increment at t i ; A2, according to the monitored leakage current value, divide it into a plurality of intervals, each interval corresponds to a leakage current correction coefficient λ ci ; The interval is divided in a nonlinear manner, and the interval range is smaller when the leakage current is larger, so as to improve the accuracy of state judgment; For example, taking a 110kV arrester as an example, 10 levels (C1~C10) are divided according to the size of the leakage current, and each level corresponds to a leakage current correction coefficient , and the leakage current correction coefficient division rule is shown in Table 1: Table 1 Leakage current correction coefficient division rule table ; A3, according to the monitored lightning current impact value, it is divided into a plurality of intervals, each interval corresponds to a lightning current correction coefficient λ Ii , the greater the lightning current value, the greater the corresponding correction coefficient λ Ii , reflecting the accelerated effect of lightning current impact on the aging of the lightning arrester; For example, according to the size of the lightning current, 10 levels (I1~I10) are divided, and each level corresponds to a lightning current correction coefficient ; The lightning current correction coefficient division rule is shown in Table 2: Table 2 Lightning current correction coefficient division rule table ; A4, define the leakage current weight WC i , the lightning current weight WI i (satisfying WC i +WI i =1), the weight is dynamically adjusted with the level, corresponding to WC1~WC n , WI1~WI n ; The influence factor ψ i of the current moment is: ; According to this, the corrected temperature capacity : ; Accordingly: add the corrected temperature capacity increment to the total temperature capacity, that is ; Wherein, n is the total number of set collection time; It should be noted that the cumulative temperature capacity TC obtained by real-time comparison is compared with the preset threshold value, and when TC exceeds the threshold value, it is determined that the aging state of the lightning arrester reaches the critical point, and immediately displays the alarm information through the local break code display screen and sends the alarm data to the remote monitoring center through the wireless communication module.

[0020] Example three, the lightning arrester online monitoring system based on self-power supply provided by the application, its system working mode is as follows: S1, the system starts running immediately after accessing the lightning arrester, the power module obtains power from the leakage current of the lightning arrester, and the power management module converts the power voltage into a stable 5V system voltage, and each module of the system completes the self-checking and parameter initialization process; S2, the SOC control module realizes periodic collection through the internal timer, and the timer wakes up the SOC control module in the sleep state, and executes the collection task in order; The temperature collection stage reads the lightning arrester body temperature TMOV and the ambient temperature TEV and stores the temperature data and the corresponding time stamp; The leakage current collection stage controls the solid-state relay to be turned on and temporarily suspends the power taking function, the operational amplifier starts to work and collects the leakage current signal, the signal is sent to the ADC module of the SOC through the conditioning circuit, and after the collection is completed, the SOC closes the solid-state relay to reduce the power consumption of the operational amplifier; The collected data is subjected to software filtering, average value processing and comparison and calibration with a standard source to obtain an accurate leakage current value; S3, in the lightning stroke event detection process, the light coupling output end remains high during normal operation, the light coupling is turned on and the output end becomes low when a lightning stroke occurs, the SOC immediately records the lightning action and makes the counter accumulate once after detecting the falling edge signal, and the current lightning current impulse value is collected, the lightning time and lightning current data are stored; S4, the discretized temperature capacity increment TCt is calculated according to the temperature data of adjacent sampling time i ; The leakage current correction coefficient λc is determined according to the current collected leakage current value in the correction coefficient determination stage i ; the lightning current correction coefficient λI is determined according to the lightning current value when a lightning stroke occurs i , and the default lightning current correction coefficient is used when there is no lightning stroke event; The influence factor is calculated by the formula , then the corrected temperature capacity is calculated , and finally the corrected TCt i is added to the total temperature capacity TC to complete the accumulation process, that is ; It should be noted that the dynamic weight adjustment determines the leakage current weight WC i and the lightning current weight WI i according to the current operating state and maintains the constraint condition that WC i + WI i =1, and the weight value is adjusted in real time according to the leakage current level and the lightning current impulse condition; S5, the accumulated temperature capacity TC is compared with the preset threshold value in real time, when the TC exceeds the threshold value, it is determined that the aging state of the lightning arrester reaches the critical point, and alarm information is displayed immediately through the local fault code display screen and alarm data is sent to the monitoring center through the 433MHz wireless module; S6, the fault code display screen displays the current leakage current value, the number of lightning actions, the accumulated temperature capacity and the system operating state and other key parameters in real time, and the 433MHz module sends the monitoring data at a set period and actively uploads the alarm information when an alarm occurs; S7. In the non-acquisition period, the SOC control module automatically enters a sleep state, the display screen maintains a minimum power consumption display mode, only the timer and necessary interrupt sources remain in working state, and when the next timer expires, the system is re-awakened and a new acquisition cycle is started; S8. The system continuously performs the above steps S1-S7, adaptively adjusts the weight distribution according to long-term operation data, and updates the arrester health state assessment in real time, to ensure accurate monitoring throughout the arrester life cycle.

[0021] The embodiments of the present application are described in detail above with reference to the drawings, but the present application is not limited thereto, and various changes can be made within the knowledge of those skilled in the art without departing from the spirit of the present application.

Claims

1. An online monitoring system for surge arresters based on self-powered power supply, characterized in that, include: The power extraction module is used to extract electrical energy from the leakage current of the surge arrester; The power management module connects to the power acquisition module and is used to convert the electrical energy obtained by the power acquisition module into a stable system voltage and supply power to other modules in the system. The lightning strike counting module is used to detect and record the number of lightning strikes suffered by the surge arrester. Leakage current acquisition module is used to acquire the leakage current value of the surge arrester; Temperature monitoring module is used to collect the temperature of the surge arrester body and the ambient temperature in real time; The display and communication module is used to display monitoring data locally and send data to a remote monitoring center. The SOC control module is connected to the power management module, lightning strike counting module, leakage current acquisition module, temperature monitoring module, and display and communication module, respectively. The SOC control module is configured as follows: The temperature capacity increment is calculated based on the surge arrester body temperature and ambient temperature collected by the temperature monitoring module. Obtain the leakage current correction factor determined by the current leakage current value, and the lightning current correction factor determined by the lightning strike event and the lightning current value; Using the leakage current correction coefficient and the lightning current correction coefficient, combined with the dynamically adjusted leakage current weight and lightning current weight, the influence factor is calculated, and the temperature capacity increment is corrected. The cumulative temperature capacity is obtained by accumulating the corrected temperature capacity increment, and the aging status of the surge arrester is evaluated based on the cumulative temperature capacity. An alarm is triggered when the threshold is exceeded.

2. The online monitoring system for surge arresters based on self-powered power supply according to claim 1, characterized in that, The power supply module includes a varistor and a power supply bypass; The power bypass consists of several resistors connected in series; When the surge arrester is operating normally, the varistor is in a high-resistance state, and the leakage current flows through the power bypass to provide power to the system.

3. The online monitoring system for surge arresters based on self-powered power supply according to claim 1, characterized in that, The power management module integrates several tantalum capacitors to provide instantaneous power when the system is transmitting wireless data and collecting leakage current.

4. The online monitoring system for surge arresters based on self-powered power supply according to claim 1, characterized in that, The lightning strike counting module uses an optocoupler for lightning strike detection; When the system is running normally, the optocoupler outputs a high level; when a lightning strike occurs, the optocoupler turns on and outputs a low level to the SOC control module. After detecting the falling edge signal, the SOC control module accumulates and counts the number of lightning strikes.

5. The online monitoring system for surge arresters based on self-powered power supply according to claim 1, characterized in that, The leakage current acquisition module includes a solid-state relay, an operational amplifier, and a signal conditioning circuit. The SOC control module switches between the system's leakage current acquisition state and power supply state by controlling the on and off states of the solid-state relays. In the leakage current acquisition state, the operational amplifier works, and the acquired leakage current signal is processed by the signal conditioning circuit and then sent to the analog-to-digital converter of the SOC control module.

6. The online monitoring system for surge arresters based on self-powered power supply according to claim 1, characterized in that, The display and communication module includes a broken code display screen and a wireless communication module; The fault code display screen is used to locally display leakage current value, number of lightning strikes, cumulative temperature capacity, and system operating status; The wireless communication module is used to send monitoring data and alarm information to the remote monitoring center.

7. The online monitoring system for surge arresters based on self-powered power supply according to claim 1, characterized in that, The SOC control module periodically wakes up the system through its internal timer, controls the temperature monitoring module and leakage current acquisition module to sequentially execute data acquisition tasks, and controls the system to enter sleep mode during non-acquisition periods.

8. A surge arrester online monitoring system based on self-powered power supply according to any one of claims 1 to 7, characterized in that, The SOC control module calculates the temperature capacity used to assess the aging condition of the surge arrester in the following manner: Obtain the surge arrester body temperature and ambient temperature at several consecutive time points, and calculate the temperature capacity increment between adjacent time points. ; in, For t i The temperature of the surge arrester at all times; For t i Ambient temperature at all times; Based on the currently collected leakage current value, consult the preset leakage current level and correction coefficient comparison table to determine the corresponding leakage current correction coefficient λ. ci ; Based on whether a lightning strike occurred and the lightning current value, consult the preset lightning current level and correction factor table to determine the corresponding lightning current correction factor λ. Ii ; Based on the leakage current correction coefficient and the lightning current correction coefficient, combined with the dynamically adjusted leakage current weight WC i Lightning current weight WI i Calculate the influence factor at the current moment. ; The temperature capacity increment is corrected using an influencing factor to obtain the corrected temperature capacity. : ; The corrected temperature capacity increment is added to the total temperature capacity, i.e. ; Where n is the total number of data collection times set; The system compares the cumulative temperature capacity (TC) with a preset threshold in real time. When the TC exceeds the threshold, it determines that the aging state of the surge arrester has reached the critical point. The system immediately displays the alarm information on the local fault code display screen and sends the alarm data to the remote monitoring center via the wireless communication module.

9. The online monitoring system for surge arresters based on self-powered power supply according to claim 8, characterized in that, The corresponding leakage current correction coefficient is determined based on the currently collected leakage current value, including: dividing the monitored leakage current value into several preset leakage current intervals, each leakage current interval corresponding to a leakage current correction coefficient; wherein, the division of leakage current intervals adopts a non-linear method, the larger the leakage current value, the smaller the corresponding interval range. The corresponding lightning current correction coefficient is determined based on whether a lightning strike event has occurred and the lightning current value. This includes dividing the monitored lightning current impact value into several preset lightning current intervals, with each lightning current interval corresponding to a lightning current correction coefficient. The larger the lightning current value, the larger the corresponding lightning current correction coefficient.

Images