Multifunctional monitoring system and method for grounding grid corrosion based on three electrodes

Abstract

The present invention provides a multifunctional monitoring system and method for grounding grid corrosion based on three electrodes. The system includes an upper computer and a lower computer component; the upper computer component includes a cloud server, a database and a client; the lower computer component includes a microcontroller, a data detection module, a sensor module, a dielectric resistance detection module, a power module, a function switching module, and a wireless transmission module; the function switching module, the data detection module, and the sensor module are connected in sequence to perform constant voltage and constant current mode signal application and switching; the sensor module includes a working electrode, an auxiliary electrode and a reference electrode, and the three electrodes are made of different materials; the method is based on an improved weighted average fusion algorithm to perform data fusion in constant voltage and constant current modes, and the monitoring results are more accurate. It solves the problems of inconvenience of monitoring in the traditional mode, lack of long-term unmanned monitoring, single function of the traditional monitoring circuit, unsuitable for multi-attribute soil corrosion monitoring, and difficulty in accurately judging the corrosion state of the grounding grid.

Description

Technical Field

[0001] The present invention belongs to the field of grounding grid corrosion state monitoring technology, and in particular relates to a three-electrode-based grounding grid corrosion multifunctional monitoring system and method. Background Art

[0002] Grounding grids are widely used in power substations in China, and they play an important role in the reliable operation of power systems and the personal safety of workers. Domestic grounding grid materials generally use flat steel or galvanized steel, which are buried underground all year round and are prone to corrosion and fracture, resulting in a reduction in the cross-section of the grounding grid conductor and insufficient thermal stability. Especially in highly corrosive soils, this grounding grid corrosion phenomenon is particularly serious. Once a corrosion failure occurs in a power substation, it will cause a major safety accident, bringing immeasurable economic losses and social impacts. Therefore, it is urgent to regularly monitor the status of the grounding grid, understand the corrosion of the grounding electrode in the soil and the electrical performance of the grounding grid, and detect problems as early as possible and take corresponding protective measures.

[0003] At present, the corrosion condition of the grounding grid is mainly measured by excavation inspection. The facilities are quite bulky, difficult to move on site, inconvenient for regular monitoring, and difficult to accurately measure the corrosion condition of the grounding grid. For some power plants with large grounding ranges and wide locations, it is impossible to dig out all the grounding bodies for inspection. Generally, the method of point selection inspection is adopted. This method has great limitations and cannot fully reflect the actual corrosion condition of the grounding body. The long-term monitoring capacity is insufficient and rapid automatic monitoring cannot be achieved. Summary of the invention

[0004] In order to solve the above problems, the present invention provides a multifunctional monitoring system and method for grounding grid corrosion based on three electrodes. In view of the current problems of large instrument size and low efficiency, a portable long-term monitoring method is proposed; in view of the single monitoring mode and other problems, a multifunctional multiplexing circuit is proposed; in view of the accuracy of detection data, an improved weighted average fusion algorithm is proposed. The problems that the excavation detection facilities in the traditional mode are bulky and large, difficult to transport, not conducive to long-term unmanned monitoring, insufficient remote monitoring capabilities, and the traditional monitoring system has a single function and is not suitable for soil corrosion monitoring of multiple attributes, and it is difficult to accurately judge the corrosion status of the entire grounding grid.

[0005] According to a first aspect of the present invention, a three-electrode-based grounding grid corrosion multifunctional monitoring system comprises: an upper computer component and a lower computer component;

[0006] The host computer components include: a client, a cloud server and a database;

[0007] The lower computer components include: a microcontroller, a dielectric resistance detection module, a function switching module, a data detection module, a sensor module, a power module and a wireless transmission module;

[0008] The cloud server is connected to the client and the database respectively, the database is connected to the wireless transmission module, and the wireless transmission module is connected to the microcontroller;

[0009] The power supply module is connected to the microcontroller, the microcontroller is respectively connected to the dielectric resistance detection module and the function switching module, the function switching module is connected to the data detection module, and the data detection module and the dielectric resistance detection module are both connected to the sensor module;

[0010] The multifunctional switching module is used to control the constant potential or constant current working mode applied by the data detection module to the sensor module;

[0011] The dielectric resistance detection module is used to detect the soil dielectric resistance value between two electrodes;

[0012] The sensor module is used to convert the ground grid corrosion status information into calculable voltage and current values ​​in constant current and constant potential modes;

[0013] The wireless transmission module is used to upload the grounding grid corrosion status information to the cloud server, and the cloud server stores the information in a database for recording and receives a client request to transmit the corrosion status information.

[0014] Preferably, the sensor module comprises a working electrode, an auxiliary electrode and a reference electrode;

[0015] The working electrode is made of flat steel material and is made into a rectangular sheet shape;

[0016] The auxiliary electrode is made of graphite material and is also made into a rectangular sheet shape, but its surface area is much larger than that of the working electrode;

[0017] The reference electrode is made of Ag / AgCl material, is made into a long cylindrical shape, and is arranged between the working electrode and the auxiliary electrode;

[0018] The working electrode, auxiliary electrode and reference electrode are arranged vertically opposite to each other, with their bottom edges parallel. One side of the three electrodes is fixed with organic material, soil medium is filled between the opposite surfaces of the three electrodes, and the upper ends of the three electrodes are led out with shielded wires.

[0019] Preferably, the dielectric resistance detection module comprises: an analog switch A, an analog switch B and an operational amplifier A0;

[0020] One end of analog switch A is connected to the gear resistor Rd and then grounded, and the other end is connected to the negative electrode of operational amplifier A0; the positive electrode of operational amplifier A0 is connected to the current limiting resistor Rc and then connected to the +1.25V power supply. Operational amplifier A0 is powered by a +3.3V single power supply; one end of analog switch B is connected to the output end and the negative electrode of operational amplifier A0, and the other end is connected between three electrodes, and the soil dielectric resistance between the electrodes is Rx; the voltage signal at the output end of operational amplifier A0 is Vr, that is, the detection voltage. By calculating the relationship between the gear resistor Rd and Vr, the soil dielectric resistance value in the current environment can be measured.

[0021] Preferably, the data detection module includes operational amplifiers A1, A2 and A3, which are used to realize multifunctional detection of constant current and constant potential;

[0022] The positive electrode of the operational amplifier A1 is connected to the current limiting resistor R1 and the input signal Vi, the output end of the operational amplifier A1 is connected to the auxiliary electrode, the negative electrode of the operational amplifier A1 is grounded through the resistor R2, and is also connected to the output end and the negative electrode of the operational amplifier A2 through the resistor R3; the positive electrode of the operational amplifier A2 is connected to the reference electrode; the positive electrode of the operational amplifier A3 is connected to the reference voltage signal Vc, the negative electrode of the operational amplifier A3 is connected to the working electrode, and is also connected to the output end through the resistor R4, and the output end signal V O That is the corrosion detection signal; operational amplifiers A1, A2, and A3 adopt a +3.3V single power supply working mode to reduce power consumption and reduce the size of the instrument.

[0023] Preferably, the function switching module uses two four-channel analog switches C and D;

[0024] The c1 terminal of the analog switch C is used to switch the positive electrode of the operational amplifier A1 to connect the input signal or the reference electrode; the c2 terminal is used to switch the input signal to flow to the positive electrode or the working electrode of the operational amplifier A1; the c3 terminal is used to switch the output signal of the operational amplifier A1 to flow to the auxiliary electrode or the negative electrode of the operational amplifier A3; the c4 terminal is used to switch the negative electrode signal of the operational amplifier A1 to flow to the output terminal of the operational amplifier A1 or to ground through the resistor R5;

[0025] The d1 terminal of the analog switch D is used to control the positive signal of the operational amplifier A2, which is derived from the reference electrode or the ground wire; the d2 terminal is used to control the output signal of the operational amplifier A2 to flow to the auxiliary electrode or to be connected to the resistor R6; the d3 terminal is used to control the negative signal of the operational amplifier A2, which is derived from the input signal or the resistor R6; the d4 terminal is used to control the negative signal of the operational amplifier A3, which is derived from the output signal of the operational amplifier A1 or the working electrode;

[0026] The use of two four-channel analog switches can realize multiple functions of a single data detection module and perform constant current and constant potential detection.

[0027] Preferably, the power module comprises: a lithium battery, a power controller and a solar charging panel;

[0028] The solar charging panel is used to charge the lithium battery and is connected to the power controller; the lithium battery is used to power the monitoring system and is connected to the power controller; the power controller is used to coordinate the charging and discharging issues between the solar charging panel and the lithium battery and is connected to the system circuit.

[0029] Preferably, the lower computer component further includes a human-computer interaction module, and the human-computer interaction module is connected to the microcontroller.

[0030] Preferably, the wireless transmission module transmits the corrosion status parameters of the grounding grid and uses a 4G module to transmit data to a cloud server. The cloud server saves the data in a MySQL database to facilitate storage and call of information, which can be retrieved through a WeChat applet to achieve long-distance corrosion monitoring.

[0031] According to a second aspect of the present invention, a three-electrode grounding grid corrosion multifunctional monitoring method is implemented based on the grounding grid corrosion multifunctional monitoring system, comprising the following steps:

[0032] Step S1: Divide the entire grounding grid site into regions, install sensor modules in each region according to the preset buried depth, lead them out of the ground through wires, and connect them to the microcontroller;

[0033] Step S2: The microcontroller controls the dielectric resistance detection module to measure the soil dielectric resistances Rs1, Rs2, and Rs3;

[0034] Step S3: the microcontroller measures the polarization current in the constant potential mode and the polarization voltage in the constant current mode on the working electrode;

[0035] Step S4: construct a mathematical model for grounding grid corrosion detection, and substitute the detection results of steps S2 and S3 into the model to calculate the corrosion current density on the working electrode;

[0036] Step S5: using an improved weighted average fusion algorithm to fuse the corrosion current density in the constant potential and constant current modes, calculating the corrosion rate through the fused corrosion current density, obtaining the corrosion state of the grounding grid in the corresponding area, and judging the safety performance of the grounding grid;

[0037] Step S6: The fused grounding grid corrosion status is uploaded to the cloud server through the wireless transmission module. The cloud server stores the information in the database for recording and receives a client request to transmit the corrosion status information.

[0038] Preferably, in step S4, the step of constructing a grounding grid corrosion detection mathematical model includes:

[0039] S4-1: Obtain soil dielectric resistance Rs1, Rs2, Rs3 between two electrodes;

[0040] S4-2: applying a constant potential step voltage signal E, increasing by 1 mV each time, with a range of -10 mV to +10 mV, to achieve positive and negative voltage application, and obtaining the corresponding polarization current value I when the voltage changes;

[0041] S4-3: The slope of the EI curve is the electrochemical reaction resistance value Rz, Rz = Rp + Rs, Rp is the polarization resistance, Rs is the equivalent soil dielectric resistance between electrodes, Rs = (Rs1*Rs2) / (Rs1+Rs2+Rs3), and the formula for calculating the polarization resistance is:

[0042]

[0043] S4-4: According to the Stern-Geary formula, the corrosion current density Where B is the electrochemical reaction constant, which is 25mV. Substitute it into the calculated R p The corrosion current density can be calculated.

[0044] Preferably, step S5 includes: performing data preprocessing on the corrosion current density of the grounding grid detected by the multifunctional switching module, that is, using a mean algorithm to eliminate large values ​​that deviate from the mean in the data, obtaining new data to supplement, and adaptively cycling multiple times until the maximum value deviates from the mean by no more than a preset value (0.1); performing data fusion on the corrosion current density obtained by the constant current detection method and the constant potential detection method based on an improved weighted average fusion algorithm, that is, using an adaptive weighted value judgment, according to the soil medium resistance value in the detection data, adaptively selecting the weight ratio of the constant potential and constant current detection results, and finally performing data fusion of the results of the two different detection methods based on the weight ratio to obtain the fused corrosion current density; calculating the corrosion rate through the fused corrosion current density, obtaining the corrosion state of the grounding grid in the corresponding area, and judging the safety performance of the grounding grid.

[0045] Preferably, the installation method in step S1 is: install the sensor module near the top of the grounding grid, lead out the wires to connect to the lower computer mainboard, install the solar charging panel on the bracket, connect it to the lower computer mainboard, install the wireless transmission module antenna, and install it on the top of the bracket; select different soil properties areas of the grounding grid for installation in the same way, and try to cover the entire grounding grid.

[0046] The beneficial effects brought by the technical solution provided by the present invention are:

[0047] The present invention proposes a multifunctional monitoring system for grounding grid corrosion based on three electrodes. Firstly, taking into account the requirement of small and portable monitoring instruments in narrow places such as substations, and in order to take into account the monitoring accuracy, it is planned to adopt a long-term monitoring mode to obtain multiple groups of data for comprehensive evaluation, and to study and design the system power management part to reduce power consumption. A detachable sensor is buried deep near the grounding grid for mapping analysis, and a cloud server is built to receive corrosion data; secondly, taking into account the different soil environments of different substations, the applicable monitoring methods are also different. In order to achieve more efficient corrosion monitoring, a multifunctional monitoring method for grounding grid corrosion based on three electrodes is designed. The method can be compatible with multiple electrochemical monitoring functions, such as constant potential and constant current; finally, considering the accuracy of grounding grid corrosion status monitoring, an improved weighted average fusion algorithm is proposed to make full use of the detected data, ensure monitoring accuracy, and provide a simple data viewing method.

[0048] The present invention changes the situation that the existing grounding grid status monitoring process is complicated and the accuracy is low. In view of the current common problems, it provides a comprehensive, effective, economical and real-time solution for the monitoring and evaluation of grounding grids, and fills the gap in the international grounding grid corrosion status comprehensive monitoring and prediction instruments. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] The present invention will be further described below with reference to the accompanying drawings and embodiments, in which:

[0050] Figure 1 It is a structural schematic diagram of a multifunctional monitoring system for grounding grid corrosion based on three electrodes in an embodiment of the present invention.

[0051] Figure 2 The present invention is a schematic diagram of a sensor and its embedding of a multifunctional monitoring system for grounding grid corrosion based on three electrodes in an embodiment of the present invention.

[0052] Figure 3 It is a schematic diagram of a dielectric resistance detection module of a three-electrode-based grounding grid corrosion multifunctional monitoring system in an embodiment of the present invention.

[0053] Figure 4 It is a schematic diagram of a data detection module of a three-electrode-based grounding grid corrosion multifunctional monitoring system in an embodiment of the present invention.

[0054] Figure 5 It is a schematic diagram of a function switching module of a three-electrode-based grounding grid corrosion multifunctional monitoring system in an embodiment of the present invention.

[0055] Figure 6 It is a function switching list of an analog switch array of a three-electrode grounding grid corrosion multifunctional monitoring system in an embodiment of the present invention.

[0056] Figure 7 It is a schematic diagram of the structure of a power module of a three-electrode grounding grid corrosion multifunctional monitoring system in an embodiment of the present invention.

[0057] Figure 8 It is a flow chart of a multifunctional monitoring method for grounding grid corrosion based on three electrodes in an embodiment of the present invention. DETAILED DESCRIPTION

[0058] In order to have a clearer understanding of the technical features, purposes and effects of the present invention, specific embodiments of the present invention are now described in detail with reference to the accompanying drawings.

[0059] refer to Figure 1 ,This embodiment provides a three-electrode-based grounding grid corrosion multifunctional monitoring system, including: an upper computer component and a lower computer component;

[0060] The host computer components include: a client, a cloud server and a database;

[0061] The lower computer components include: a microcontroller, a dielectric resistance detection module, a function switching module, a data detection module, a sensor module, a power module and a wireless transmission module;

[0062] The cloud server is connected to the client and the database respectively, the database is connected to the wireless transmission module, and the wireless transmission module is connected to the microcontroller;

[0063] The power supply module is connected to the microcontroller, the microcontroller is respectively connected to the dielectric resistance detection module and the function switching module, the function switching module is connected to the data detection module, and the data detection module and the dielectric resistance detection module are both connected to the sensor module;

[0064] The multifunctional switching module is used to control the constant potential or constant current working mode applied by the data detection module to the sensor module;

[0065] The dielectric resistance detection module is used to detect the soil dielectric resistance value between two electrodes;

[0066] The sensor module is used to convert the ground grid corrosion status information into calculable voltage and current values ​​in constant current and constant potential modes;

[0067] The wireless transmission module is used to upload the grounding grid corrosion status information to the cloud server, and the cloud server stores the information in a database for recording and receives a client request to transmit the corrosion status information.

[0068] The upper computer component uses MySQL to build a database, which mainly stores the final decision on the corrosion status of the grounding grid, the grounding grid area information and the time scale; the http server is built using the Java language, which is used to receive data uploaded by the lower computer and store it in the database, and at the same time receive client request data information and retrieve database stored data; the client uses the WeChat applet mode, and the corrosion status is displayed in the form of a curve drawing, with the horizontal axis being time and the vertical axis being the corrosion status, and past records can be queried at the same time.

[0069] refer to Figure 1 As an optional implementation, the lower computer component also includes a human-computer interaction module, and the human-computer interaction module is connected to the microcontroller.

[0070] refer to Figure 2 , the sensor module includes a working electrode, an auxiliary electrode and a reference electrode;

[0071] The working electrode is made of flat steel material of the same material as the grounding grid, made into a thin sheet, and placed opposite to the auxiliary electrode, with a smaller area than the auxiliary electrode; the auxiliary electrode is made of conductive graphite material, also made into a thin sheet; the reference electrode is made of Ag / AgCl material, made into a cylindrical shape, and placed between the working electrode and the auxiliary electrode; the electrodes are arranged vertically opposite to each other and fixed on the same horizontal plane with organic materials in a cylindrical shape; the sensor is buried near the grounding grid, with soil as the medium between the electrodes, and the upper end of the electrode is led out with a shielded wire, which is respectively connected to the medium resistance detection module and the data detection module.

[0072] refer to Figure 3 , the dielectric resistance detection module includes: an analog switch A, an analog switch B and an operational amplifier A0;

[0073] One end of analog switch A is connected to the gear resistor Rd and then grounded, and the other end is connected to the negative electrode of operational amplifier A0; the positive electrode of operational amplifier A0 is connected to the current limiting resistor Rc and then connected to the +1.25V power supply. Operational amplifier A0 is powered by a +3.3V single power supply; one end of analog switch B is connected to the output end and the negative electrode of operational amplifier A0, and the other end is connected between three electrodes, and the soil dielectric resistance between the electrodes is Rx; the voltage signal at the output end of operational amplifier A0 is Vr, that is, the detection voltage. By calculating the relationship between the gear resistor Rd and Vr, the soil dielectric resistance value in the current environment can be measured.

[0074] After the dielectric resistance detection is completed, the electrochemical method is used to detect the corrosion of the grounding grid. The data detection module is connected to the sensor module, and different excitation signals are input to obtain a response signal. The data detection module is mainly responsible for executing constant current and constant potential functions.

[0075] refer to Figure 4, the data detection module includes operational amplifiers A1, A2 and A3; the positive electrode of operational amplifier A1 is connected to the current limiting resistor R1 and the input signal Vi, the output end of operational amplifier A1 is connected to the auxiliary electrode, the negative electrode of operational amplifier A1 is grounded through resistor R2, and is also connected to the output end and negative electrode of operational amplifier A2 through resistor R3; the positive electrode of operational amplifier A2 is connected to the reference electrode; the positive electrode of operational amplifier A3 is connected to the reference voltage signal Vc, the negative electrode of operational amplifier A3 is connected to the working electrode, and is also connected to the output end through resistor R4, and the output end signal VO of operational amplifier A3 is the corrosion detection signal; operational amplifiers A1, A2, A3 adopt +3.3V single power supply working mode to reduce power consumption and reduce instrument size. At the same time, positive and negative voltage application and positive and negative current detection can be performed, which expands the detection range.

[0076] refer to Figure 5 , the function switching module adopts two four-channel analog switches C and D;

[0077] The c1 terminal of the analog switch C is used to switch the positive electrode of the operational amplifier A1 to connect the input signal or the reference electrode; the c2 terminal is used to switch the input signal to flow to the positive electrode or the working electrode of the operational amplifier A1; the c3 terminal is used to switch the output signal of the operational amplifier A1 to flow to the auxiliary electrode or the negative electrode of the operational amplifier A3; the c4 terminal is used to switch the negative electrode signal of the operational amplifier A1 to flow to the output terminal of the operational amplifier A1 or to ground through the resistor R5;

[0078] The d1 terminal of the analog switch D is used to control the positive signal of the operational amplifier A2, which is derived from the reference electrode or the ground wire; the d2 terminal is used to control the output signal of the operational amplifier A2 to flow to the auxiliary electrode or to be connected to the resistor R6; the d3 terminal is used to control the negative signal of the operational amplifier A2, which is derived from the input signal or the resistor R6; the d4 terminal is used to control the negative signal of the operational amplifier A3, which is derived from the output signal of the operational amplifier A1 or the working electrode;

[0079] The use of two four-channel analog switches can realize multiple functions of a single data detection module and perform constant current and constant potential detection.

[0080] refer to Figure 6 It is a multifunctional switching table for circuits. It controls the C and D analog switches in different opening and closing modes, and can perform current method and voltage method detection. By applying current and voltage in different ways through the digital-to-analog converter, a variety of functional detection methods can be realized, including: constant potential polarization method, constant potential step method, AC impedance method, voltammetry method in constant potential method, constant current polarization method, constant current step method, and chronoamperometry in constant current method.

[0081] refer to Figure 7As an optional implementation, in the power module, a lithium battery is used as the power supply, an analog switch E is used to control the charging and discharging of the lithium battery, a solar charging panel is used as a power supply device, and a linear regulator is used for step-down output, which respectively supplies power to the analog circuit and the digital circuit. In other embodiments, more power supply modes can also be selected.

[0082] refer to Figure 8 , a multifunctional monitoring method for grounding grid corrosion based on three electrodes, the detection process includes:

[0083] Step S1: Divide the entire grounding grid site into regions, install sensor modules in each region according to the preset buried depth, lead them out of the ground through wires, and connect them to the microcontroller;

[0084] Step S2: The microcontroller controls the dielectric resistance detection module to measure the soil dielectric resistances Rs1, Rs2, and Rs3;

[0085] Step S3: the microcontroller measures the polarization current in the constant potential mode and the polarization voltage in the constant current mode on the working electrode;

[0086] Step S4: construct a mathematical model for grounding grid corrosion detection, and substitute the detection results of steps S2 and S3 into the model to calculate the corrosion current density on the working electrode;

[0087] Step S5: using an improved weighted average fusion algorithm to fuse the corrosion current density in the constant potential and constant current modes, calculating the corrosion rate through the fused corrosion current density, obtaining the corrosion state of the grounding grid in the corresponding area, and judging the safety performance of the grounding grid;

[0088] Step S6: The fused grounding grid corrosion status is uploaded to the cloud server through the wireless transmission module. The cloud server stores the information in the database for recording and receives a client request to transmit the corrosion status information.

[0089] Furthermore, S4 includes:

[0090] S4-1: Obtain soil dielectric resistance Rs1, Rs2, Rs3 between two electrodes;

[0091] S4-2: applying a constant potential step voltage signal E, increasing by 1 mV each time, with a range of -10 mV to +10 mV, to achieve positive and negative voltage application, and obtaining the corresponding polarization current value I when the voltage changes;

[0092] S4-3: The slope of the EI curve is the electrochemical reaction resistance value Rz, Rz = Rp + Rs, Rp is the polarization resistance, Rs is the equivalent soil dielectric resistance between electrodes, Rs = (Rs1*Rs2) / (Rs1+Rs2+Rs3), and the formula for calculating the polarization resistance is:

[0093]

[0094] S4-4: According to the Stern-Geary formula, the corrosion current density Where B is the electrochemical reaction constant, which is 25mV. Substitute it into the calculated R p The corrosion current density can be calculated.

[0095] Furthermore, step S5 includes: performing data preprocessing on the corrosion current density of the grounding grid detected by the multifunctional switching module, that is, using the mean algorithm to eliminate the large values ​​that deviate from the mean in the data, obtain new data to supplement, and adaptively cycle multiple times until the maximum value deviates from the mean by no more than 0.1; performing data fusion on the corrosion current density obtained by the constant current detection method and the constant potential detection method based on the improved weighted average fusion algorithm, that is, using adaptive weighted value judgment, according to the soil medium resistance value in the detection data, adaptively selecting the weight ratio of the constant potential and constant current detection results, and finally performing data fusion of the results of the two different detection methods based on the weight ratio to obtain the fused corrosion current density; calculating the corrosion rate through the fused corrosion current density, obtaining the corrosion state of the grounding grid in the corresponding area, and judging the safety performance of the grounding grid.

[0096] The installation method in step S1 is: install the sensor module near the top of the grounding grid, lead out the wire to connect to the lower computer mainboard, install the solar charging panel on the bracket, connect it to the lower computer mainboard, install the wireless transmission module antenna, and install it on the top of the bracket; select different soil properties of the grounding grid for installation in the same way, and try to cover the entire grounding grid.

[0097] The key technical points of the present invention are:

[0098] 1. In view of the requirements of power consumption control, sensor design and Internet of Things functions for the miniaturization and portability of the grounding grid corrosion monitoring instrument, a mobile rechargeable lithium battery is used to power the instrument to achieve positive and negative current detection and positive and negative voltage application in single power mode, reduce circuit power consumption, and reduce the size of the instrument; a wireless transmission module is used to build a cloud server to achieve long-term automatic monitoring of the grounding system; a detachable three-electrode electrochemical state sensor is used to improve the portability of the instrument, making it easy to disassemble and install the monitoring instrument, thereby improving the overall work efficiency of the instrument.

[0099] 2. The grounding grid corrosion monitoring instrument has multiple electrochemical monitoring methods and can meet the monitoring method requirements in different occasions. A multifunctional switching circuit is designed, the circuit structure is optimized, the instrument size is effectively guaranteed, and the function can be switched between constant potential method and constant current method. Multiple electrochemical monitoring methods are realized, and negative voltage and negative current signal detection research is carried out to expand the detection range.

[0100] 3. In order to ensure the accuracy of the decision on the corrosion status of the grounding grid, the corrosion current of the grounding grid detected by the multifunctional monitoring system is preprocessed, that is, the mean algorithm is used to eliminate the large values ​​that deviate from the mean in the data; based on the improved weighted average fusion algorithm, the corrosion parameters obtained by the constant current detection method and the constant potential detection method are fused to obtain the support rate of the grounding grid corrosion situation, which is more in line with the actual situation. The authenticity and accuracy of the fused data are guaranteed, and the corrosion judgment efficiency is higher.

[0101] The present invention can realize long-term monitoring of the electrochemical monitoring system, improve portability, expand field test performance, enhance data processing and acquisition efficiency, and greatly reduce the size of the instrument; a multifunctional multiplexing circuit is designed to be compatible with a variety of electrochemical monitoring methods and realize corrosion monitoring with different requirements in various occasions; the design is based on an improved weighted average fusion algorithm to make full use of monitoring data, and the fusion results and decisions are more accurate than traditional monitoring.

[0102] It should be noted that, in this article, the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or system including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or system. In the absence of further restrictions, an element defined by the sentence "comprises a ..." does not exclude the existence of other identical elements in the process, method, article or system including the element.

[0103] The serial numbers of the embodiments of the present invention are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments. In a unit claim that lists several means, several of these means may be embodied by the same hardware item. The use of the words first, second, and third, etc. does not indicate any order and these words may be interpreted as identifiers.

[0104] The above are only preferred embodiments of the present invention, and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A three-electrode grounding grid corrosion multifunctional monitoring system, characterized in that: include: Upper computer components and lower computer components; The host computer components include: a client, a cloud server and a database; The lower computer components include: a microcontroller, a dielectric resistance detection module, a function switching module, a data detection module, a sensor module, a power module and a wireless transmission module; The cloud server is connected to the client and the database respectively, the database is connected to the wireless transmission module, and the wireless transmission module is connected to the microcontroller; The power supply module is connected to the microcontroller, the microcontroller is respectively connected to the dielectric resistance detection module and the function switching module, the function switching module is connected to the data detection module, and the data detection module and the dielectric resistance detection module are both connected to the sensor module; The function switching module is used to control the constant potential or constant current working mode applied by the data detection module to the sensor module; The dielectric resistance detection module is used to detect the soil dielectric resistance value between two electrodes; The sensor module is used to convert the ground grid corrosion status information into calculable voltage and current values ​​in constant current and constant potential modes; The wireless transmission module is used to upload the grounding grid corrosion status information to the cloud server, which stores the information in a database for recording and receives a client request to transmit the corrosion status information; The sensor module includes a working electrode, an auxiliary electrode and a reference electrode; The working electrode is made of flat steel material and is made into a rectangular sheet shape; The auxiliary electrode is made of graphite material and is also made into a rectangular sheet shape, but its surface area is much larger than that of the working electrode; The reference electrode is made of Ag / AgCl material, is made into a long cylindrical shape, and is arranged between the working electrode and the auxiliary electrode; The working electrode, the auxiliary electrode and the reference electrode are arranged vertically opposite to each other, the bottom edges of the three electrodes are parallel, one side of the three electrodes is fixed with organic material, the space between the opposite surfaces of the three electrodes is filled with soil medium, and the upper ends of the three electrodes are led out with shielded wires; The dielectric resistance detection module includes: an analog switch A, an analog switch B and an operational amplifier A0; One end of analog switch A is connected to the gear resistor Rd and then to ground, and the other end is connected to the negative electrode of operational amplifier A0; the positive electrode of operational amplifier A0 is connected to the current limiting resistor Rc and then to the +1.25V power supply, and operational amplifier A0 is powered by a +3.3V single power supply; one end of analog switch B is connected to the output end and the negative electrode of operational amplifier A0, and the other end is connected between three electrodes, and the soil dielectric resistance between the electrodes is Rx; the voltage signal at the output end of operational amplifier A0 is Vr, that is, the detection voltage, and the soil dielectric resistance value in the current environment can be measured by calculating the relationship between the gear resistor Rd and Vr; The data detection module includes operational amplifiers A1, A2 and A3, which are used to realize multifunctional detection of constant current and constant potential; The positive electrode of the operational amplifier A1 is connected to the current limiting resistor R1 and the input signal Vi, the output end of the operational amplifier A1 is connected to the auxiliary electrode, the negative electrode of the operational amplifier A1 is grounded through the resistor R2, and is also connected to the output end and the negative electrode of the operational amplifier A2 through the resistor R3; the positive electrode of the operational amplifier A2 is connected to the reference electrode; the positive electrode of the operational amplifier A3 is connected to the reference voltage signal Vc, the negative electrode of the operational amplifier A3 is connected to the working electrode, and is also connected to the output end through the resistor R4. The output end signal V O That is the corrosion detection signal; operational amplifiers A1, A2, and A3 use a +3.3V single power supply working mode to reduce power consumption and reduce the size of the instrument; The function switching module uses two four-channel analog switches C and D; The c1 terminal of the analog switch C is used to switch the positive electrode of the operational amplifier A1 to connect the input signal or the reference electrode; the c2 terminal is used to switch the input signal to flow to the positive electrode or the working electrode of the operational amplifier A1; the c3 terminal is used to switch the output signal of the operational amplifier A1 to flow to the auxiliary electrode or the negative electrode of the operational amplifier A3; the c4 terminal is used to switch the negative electrode signal of the operational amplifier A1 to flow to the output terminal of the operational amplifier A1 or to ground through the resistor R5; The d1 terminal of the analog switch D is used to control the positive signal of the operational amplifier A2, which is derived from the reference electrode or the ground wire; the d2 terminal is used to control the output signal of the operational amplifier A2 to flow to the auxiliary electrode or the resistor R6; the d3 terminal is used to control the negative signal of the operational amplifier A2, which is derived from the input signal or the resistor R6; the d4 terminal is used to control the negative signal of the operational amplifier A3, which is derived from the output signal of the operational amplifier A1 or the working electrode; The use of two four-channel analog switches can realize multiple functions of a single data detection module and perform constant current and constant potential detection.

2. The three-electrode grounding grid corrosion multifunctional monitoring system according to claim 1, characterized in that: The power module includes: a lithium battery, a power controller and a solar charging panel; The solar charging panel is used to charge the lithium battery and is connected to the power controller; the lithium battery is used to power the monitoring system and is connected to the power controller; the power controller is used to coordinate the charging and discharging issues between the solar charging panel and the lithium battery and is connected to the system circuit.

3. The three-electrode grounding grid corrosion multifunctional monitoring system according to claim 1, characterized in that: The lower computer component also includes a human-computer interaction module, and the human-computer interaction module is connected to the microcontroller.

4. A three-electrode grounding grid corrosion multifunctional monitoring method, implemented based on the grounding grid corrosion multifunctional monitoring system according to any one of claims 1 to 3, characterized in that: The following steps are involved: Step S1: Divide the entire grounding grid site into regions, install sensor modules in each region according to the preset buried depth, lead them out of the ground through wires, and connect them to the microcontroller; Step S2: The microcontroller controls the dielectric resistance detection module to measure the soil dielectric resistances Rs1, Rs2, and Rs3; Step S3: the microcontroller measures the polarization current in the constant potential mode and the polarization voltage in the constant current mode on the working electrode; Step S4: construct a mathematical model for grounding grid corrosion detection, and substitute the detection results of steps S2 and S3 into the model to calculate the corrosion current density on the working electrode; Step S5: using an improved weighted average fusion algorithm to fuse the corrosion current density in the constant potential and constant current modes, calculating the corrosion rate through the fused corrosion current density, obtaining the corrosion state of the grounding grid in the corresponding area, and judging the safety performance of the grounding grid; Step S6: uploading the fused grounding grid corrosion status to the cloud server through the wireless transmission module, the cloud server stores the information in the database for recording, and receives the client's request to transmit the corrosion status information; In step S4, the step of constructing a mathematical model for grounding grid corrosion detection includes: S4-1: Obtain soil dielectric resistance Rs1, Rs2, Rs3 between two electrodes; S4-2: applying a constant potential step voltage signal E, increasing by 1 mV each time, with a range of -10 mV to +10 mV, to achieve positive and negative voltage application, and obtaining the corresponding polarization current value I when the voltage changes; S4-3: The slope of the EI curve is the electrochemical reaction resistance value Rz, Rz=Rp+Rs, Rp is the polarization resistance, Rs is the equivalent soil dielectric resistance between electrodes, Rs=(Rs1*Rs2) / (Rs1+Rs2+Rs3), and the formula for calculating the polarization resistance is: S4-4: According to the Stern-Geary formula, the corrosion current density ,in B is the electrochemical reaction constant, and the calculated R p The numerical value can be used to calculate the corrosion current density; Step S5 includes: performing data preprocessing on the corrosion current density of the grounding grid detected by the multifunctional switching module, that is, using the mean algorithm to eliminate the large values ​​that deviate from the mean in the data, obtain new data to supplement, and adaptively cycle multiple times until the maximum value deviates from the mean by no more than a preset value; performing data fusion on the corrosion current density obtained by the constant current detection method and the constant potential detection method based on the improved weighted average fusion algorithm, that is, using adaptive weighted value judgment, according to the soil medium resistance value in the detection data, adaptively selecting the weight ratio of the constant potential and constant current detection results, and finally fusing the data of the results of the two different detection methods based on the weight ratio to obtain the fused corrosion current density; calculating the corrosion rate through the fused corrosion current density, obtaining the corrosion state of the grounding grid in the corresponding area, and judging the safety performance of the grounding grid.

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