Intelligent monitoring method and device for high-voltage cable grounding box

Abstract

The invention provides an intelligent monitoring method for a high-voltage cable grounding box, and the method comprises the following steps: collecting the current data and voltage data of a protector grounding box, calculating the resistive current value of the protector grounding box, comparing the resistive current value of the protector grounding box with a set threshold value, and determining the current value of the protector grounding box. And fault information of the protector grounding box is accurately determined according to a comparison result. The resistive current component of the protector is calculated in real time by acquiring the induced voltage and current signals of the metal sheath and the armor layer of the high-voltage cable, so that the running state of the protector is accurately researched and judged, the breakdown frequency of the protector is counted, and when a corresponding alarm threshold value is reached, corresponding alarm information and processing measures are given, so that the safety of the protector is ensured. Real-time monitoring and comprehensive evaluation of the operation states of the high-voltage cable and the grounding box thereof are realized, and the safety and reliability of cable operation are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of power grid safety monitoring, and particularly relates to an intelligent monitoring method and device for a high-voltage cable grounding box. Background Art

[0002] In power grids and railway power supply systems, when lightning waves, internal over-voltages or system short-circuit faults occur, over-voltages or over-currents will be generated on the metal sheath and armor layer of high-voltage cables. Therefore, one end of the metal sheath and armor layer of the high-voltage cable is directly grounded, and the other end is grounded through a protector; the over-voltage induced on the metal sheath and armor layer is absorbed by the protector at the grounding end of the protector, avoiding breakdown of the cable due to over-voltage for too long a time and causing a short-circuit fault. The over-current induced on the metal sheath and armor layer flows into the ground through the direct grounding end, avoiding burning of the cable due to over-current for a long time, so as to realize the protection of the high-voltage cable against induced over-voltage and over-current.

[0003] Once the protector is irreversibly and permanently broken down, it will cause the two ends of the high-voltage cable to be directly grounded, and a loop will be formed between the induced voltage and the induced current and the ground, which will cause the cable insulation to break down, resulting in cable fires or even explosion accidents.

[0004] Therefore, it is particularly necessary to monitor the voltage and current of the metal sheath and armor layer of the high-voltage cable and the status of the protector in real time. At present, the monitoring of the metal sheath and armor layer of the high-voltage cable mainly focuses on collecting the induced power frequency current. This monitoring method cannot perform real-time monitoring and comprehensive evaluation on the operating status of the high-voltage cable and its grounding box, resulting in poor safety and reliability of the operation of the high-voltage cable. Summary of the Invention

[0005] The present invention provides an intelligent monitoring method and device for a high-voltage cable grounding box, which solves the problems that the existing high-voltage cable monitoring method cannot perform real-time monitoring and comprehensive evaluation on the operating status of the high-voltage cable and its grounding box, resulting in poor safety and reliability of the operation of the high-voltage cable.

[0006] The technical solution of the present invention is realized as follows:

[0007] In a first aspect of the present invention, an intelligent monitoring method for a high-voltage cable grounding box is provided, including the following steps:

[0008] S1, collecting current data and voltage data of the protector grounding box;

[0009] S2, calculating the resistive current value of the protector grounding box according to the phase relationship between the current data and the voltage data;

[0010] S3, judging whether the resistive current value exceeds a first current threshold. If so, go to step S4; otherwise, return to step S1;

[0011] S4. Determine whether the duration for which the resistive current value exceeds the first current threshold exceeds the set duration. If it does, determine that there is a fault in the protector and proceed to step S5; otherwise, proceed to step S7.

[0012] S5. Determine whether the resistive current value is less than the second current threshold. If it is, determine that a type III fault has occurred in the protector grounding box; otherwise, proceed to step S6.

[0013] S6. Determine whether the resistive current value is less than the third current threshold. If it is, determine that a type II fault has occurred in the protector grounding box; otherwise, determine that a type I fault has occurred in the protector grounding box.

[0014] S7. Determine that there is an instantaneous breakdown of the protector, and update the number of instantaneous breakdowns of the protector.

[0015] S8. Determine whether the number of instantaneous breakdowns of the protector exceeds the set number. If it does, determine that a type I fault has occurred in the protector grounding box; otherwise, return to step S1.

[0016] Specifically, the intelligent monitoring method further includes collecting the current data of the direct grounding box and determining whether the current value of the direct grounding box exceeds the set threshold. If it does, respond to the grounding loop current alarm; otherwise, continue to collect the current data of the direct grounding box.

[0017] In a second aspect of the present invention, there is provided an intelligent monitoring device for a high-voltage cable grounding box, including: a protector grounding box, a direct grounding box, an analog quantity acquisition unit, a signal processing and storage unit, a central processing unit, a display unit, and a communication unit;

[0018] The analog quantity acquisition unit is connected to the protector grounding box and the direct grounding box, and is used to collect the current data, voltage data of the protector grounding box, and the current data of the direct grounding box;

[0019] The signal processing and storage unit is connected to the analog quantity acquisition unit, and is used to perform preprocessing and pre-calculation on the collected current data and voltage data;

[0020] The central processing unit is connected to the signal processing and storage unit, and is used to further perform calculation and processing on the data after preprocessing and pre-calculation to determine the fault information of the line and the grounding box;

[0021] The display unit is connected to the central processing unit, and is used to display the operation information of the device and the line and the fault information of the grounding box;

[0022] The communication unit is connected to the central processing unit, and is used to connect to the remote master station system, send the monitoring information to the remote master station system, and receive the control instructions issued by the remote master station system.

[0023] Specifically, the protector grounding box is connected to the copper shielding layer and the armor layer of the high-voltage cable, and internally includes a protector, a first current sensor, a voltage sensor, a voltage terminal, and a first current terminal. The protector is connected to the grounding wire of the copper shielding layer or the armor layer of the high-voltage cable; the first current sensor is connected in series with the protector and is used to collect the current signal flowing through the protector; the voltage sensor is connected across the protector and is used to collect the voltage signal across the protector; the voltage terminal is respectively connected to the voltage sensor and the analog acquisition unit and is used to transmit the collected voltage signal to the analog acquisition unit; the first current terminal is respectively connected to the first current sensor and the analog acquisition unit and is used to transmit the collected current signal to the analog acquisition unit.

[0024] Specifically, the direct grounding box is connected to the copper shielding layer and the armor layer of the high-voltage cable, and internally includes a second current sensor and a second current terminal. The second current sensor is connected to the grounding wire of the copper shielding layer or the armor layer of the high-voltage cable and is used to collect the grounding current of the copper shielding layer or the armor layer of the high-voltage cable; the second current terminal is respectively connected to the second current sensor and the analog acquisition unit and is used to transmit the collected current signal to the analog acquisition unit.

[0025] Specifically, the analog acquisition unit includes an overvoltage protection module, a signal conditioning module, and an analog-to-digital conversion module connected in sequence. The overvoltage protection module is used to provide overvoltage protection. The signal conditioning module is used to convert the voltage signal output by the overvoltage protection module into a current signal. The analog-to-digital conversion module is used to convert the analog signal into a digital signal for output.

[0026] Specifically, the signal processing and storage unit includes a programmable logic unit, a clock management unit, and multiple storage units. The clock management unit is used to attach a time stamp to the collected signal. The storage unit is used to cache the signal with the time stamp. The programmable logic unit is used to preprocess and pre-calculate the collected signal.

[0027] Specifically, the display unit includes a display screen and several indicator lights. The display screen is used to display device information, fault information, and line operation information in real time; the indicator lights include a power indicator light, an operation indicator light, a communication indicator light, and a fault indicator light, and are used to indicate the power status, device operation status, communication connection status, and fault information.

[0028] Specifically, the communication unit includes a remote communication network port and a USB debugging interface. The remote communication network port is used to connect to the remote master station system. The USB debugging interface is used to connect to an external computer.

[0029] Compared with the prior art, the beneficial effects of the present invention are as follows: The present invention can not only judge the insulation state of the cable by collecting power frequency induction current, but also calculate the resistive current component of the protector in real time by collecting the induced voltage and current signals of the metal sheath and armor layer of the high-voltage cable, so as to accurately judge the operation state of the protector and count the breakdown times of the protector. When the corresponding alarm threshold is reached, corresponding alarm information and treatment measures are given to realize the real-time monitoring and comprehensive evaluation of the operation state of the high-voltage cable and its earthing box, and improve the safety and reliability of cable operation. Brief Description of the Drawings

[0030] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0031] Figure 1 It is a schematic flow chart of an intelligent monitoring method for a high-voltage cable earthing box of the present invention;

[0032] Figure 2 It is a structural diagram of an intelligent monitoring device for a high-voltage cable earthing box of the present invention. Detailed Embodiments

[0033] The following will clearly and completely describe the technical solutions of the present invention in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, rather than all embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts belong to the scope of protection of the present invention.

[0034] Refer to Figure 1 , the first aspect of the present invention provides an intelligent monitoring method for a high-voltage cable earthing box, including the following steps:

[0035] S1, collect the current data and voltage data of the protector earthing box;

[0036] S2, calculate the resistive current value Ir of the protector earthing box according to the phase relationship between the current data and the voltage data;

[0037] S3, judge whether the resistive current value Ir exceeds the first current threshold I1. If so, go to step S4; otherwise, return to step S1;

[0038] S4, determine whether the time duration T during which the resistive current value Ir exceeds the first current threshold value I1 exceeds a set time duration (the set time duration in this embodiment is 0.1s, and the specific time duration can be flexibly set according to actual conditions). If it exceeds, it is determined that the protector is faulty and the process proceeds to step S5, otherwise, the process proceeds to step S7;

[0039] S5, judging whether the resistive current value Ir is less than the second current threshold value I2, if so, it is judged that a Class III fault occurs in the protector grounding box, otherwise, it goes to step S6;

[0040] S6, judging whether the resistive current value Ir is less than the third current threshold value I3, if so, it is judged that the protector grounding box has a type II fault, otherwise it is judged that the protector grounding box has a type I fault;

[0041] S7, determine that the protector is instantaneously broken down, and update the number of instantaneous breakdowns of the protector n=n+1;

[0042] S8, determine whether the number n of instantaneous breakdowns of the protector exceeds the set number (the set number in this embodiment is 10,000 times, and the specific number can be flexibly set according to actual conditions). If it exceeds, it is determined that a Class I fault occurs in the protector grounding box, otherwise return to step S1.

[0043] In this embodiment, when it is determined that a Type I fault occurs in the protector grounding box, the protector needs to be replaced; when it is determined that a Type II fault occurs in the protector grounding box, the protector needs to be routinely tested and processed according to the test results; when it is determined that a Type III fault occurs in the protector grounding box, attention needs to be paid to tracking and analyzing changes in resistive current values.

[0044] Specifically, the intelligent monitoring method also includes collecting current data of the direct grounding box (this step is performed simultaneously with the aforementioned step S1), and determining whether the current value of the direct grounding box exceeds a set threshold (the threshold is set to 50A in this embodiment, and the specific threshold can be flexibly set according to actual conditions). If exceeded, a grounding loop current alarm is responded to, and the cable needs to be shut down for maintenance. Otherwise, the current data of the direct grounding box continues to be collected.

[0045] Specifically, before step S1, the intelligent detection device is initialized first, and then the data collection process is started.

[0046] Specifically, in step S2, the current sensor collects the full current, including the capacitive current component (accounting for 80% to 90% of the full current component) and the resistive current component (accounting for 10% to 20% of the full current component). The capacitive current phase leads the voltage phase by 90°, and the resistive current phase is the same as the voltage phase. The resistive current component can reflect the state of the protector, so the resistive current needs to be extracted from the full current to determine the state of the protector, where the calculation formula for the resistive current value is: I represents the phasor value of the total current, represents the initial included angle of the voltage phase.

[0047] As Figure 2 shown, the second aspect of the present invention provides an intelligent monitoring device for a high-voltage cable grounding box, including: a protector grounding box, a direct grounding box, an analog quantity acquisition unit, a signal processing and storage unit, a central processing unit, a display unit, and a communication unit;

[0048] The analog quantity acquisition unit is connected to the protector grounding box and the direct grounding box, and is used for acquiring the current data, voltage data of the protector grounding box, and the current data of the direct grounding box;

[0049] The signal processing and storage unit is connected to the analog quantity acquisition unit, and is used for preprocessing and pre-calculating the acquired current data and voltage data;

[0050] The central processing unit is connected to the signal processing and storage unit, and is used for further calculating and processing the data after preprocessing and pre-calculation to judge the fault information of the line and the grounding box;

[0051] The display unit is connected to the central processing unit, and is used for displaying the operation information of the device and the line and the fault information of the grounding box;

[0052] The communication unit is connected to the central processing unit, and is used for connecting to a remote master station system, sending the monitoring information to the remote master station system, and receiving the control instructions issued by the remote master station system.

[0053] Specifically, the protector grounding box is connected to the copper shielding layer and the armor layer of the high-voltage cable, and internally includes a protector, a first current sensor, a voltage sensor, a voltage terminal, and a first current terminal. The protector is connected to the grounding wire of the copper shielding layer or the armor layer of the high-voltage cable; the first current sensor is connected in series with the protector and is used for acquiring the current signal flowing through the protector; the voltage sensor is connected to both ends of the protector and is used for acquiring the voltage signal at both ends of the protector; the voltage terminal is respectively connected to the voltage sensor and the analog quantity acquisition unit and is used for transmitting the acquired voltage signal to the analog quantity acquisition unit; the first current terminal is respectively connected to the first current sensor and the analog quantity acquisition unit and is used for transmitting the acquired current signal to the analog quantity acquisition unit.

[0054] Specifically, the direct grounding box is connected to the copper shielding layer and the armor layer of the high-voltage cable, and internally includes a second current sensor and a second current terminal. The second current sensor is connected to the grounding wire of the copper shielding layer or the armor layer of the high-voltage cable and is used to collect the grounding current of the copper shielding layer or the armor layer of the high-voltage cable. The second current terminal is respectively connected to the second current sensor and the analog quantity acquisition unit and is used to transmit the collected current signal to the analog quantity acquisition unit.

[0055] In this embodiment, the first current sensor is a zero-flux micro-current sensor, with a monitoring range of 0.02 mA to 2 mA and a collection accuracy of 2% ± 5 μA. Its main function is to collect the current signals of the grounding wires of the copper shielding layer of the high-voltage cable and the grounding wires of the armor layer of the high-voltage cable in real time, and the collected current signals are connected to the current sensor terminal block.

[0056] In this embodiment, the second current sensor is a Rogowski coil sensor with a snap-on structure design, a sampling bandwidth of 0.1 Hz to 1 kHz, a signal input range of 0 A to 1000 A (peak-to-peak value), a signal output range of 3 to 5 V, and an accuracy of 0.5%. Its main function is to collect the current signals of the grounding wires of the copper shielding layer of the high-voltage cable and the grounding wires of the armor layer of the high-voltage cable in real time, and the collected current signals are connected to the current sensor terminal block.

[0057] In this embodiment, the voltage sensor adopts the principle of ceramic capacitor voltage division, converts the 10 kV voltage signal into a low-voltage 6.5 V signal, with a transformation ratio of: (10 kV / √3) / 6.5 V, an accuracy class of 3P, and a partial discharge of ≤ 20 (1.2Um / √3) pC. Its main function is to collect the voltage signals of the grounding wires of the copper shielding layer of the high-voltage cable and the grounding wires of the armor layer of the high-voltage cable, and the collected voltage signals are connected to the voltage sensor terminal block.

[0058] In this embodiment, the current sensor terminal block is connected to the intelligent monitoring device and is used to transmit the current signal collected by the current sensor; the voltage sensor terminal block is connected to the intelligent monitoring device and is used to transmit the voltage signal collected by the voltage sensor.

[0059] In this embodiment, the intelligent detection device further includes a stainless-steel shell, and each functional module is arranged inside the shell. The intelligent monitoring device is provided with a DC24V power supply by the power supply unit. The intelligent monitoring device collects the voltage and current data of the grounding boxes of multiple high-voltage cables through the voltage terminal block and the current terminal block, so as to realize the performance monitoring of the grounding boxes of multiple high-voltage cables.

[0060] Specifically, the power supply unit is externally connected to the AC220V mains power, and converts it into a DC24V power supply through the power supply unit to provide a power supply for the intelligent monitoring device.

[0061] Specifically, the analog quantity acquisition unit includes an overvoltage protection module, a signal conditioning module, and an analog-to-digital conversion module connected in sequence. The overvoltage protection module is used to provide overvoltage protection. The signal conditioning module is used to convert the voltage signal output by the overvoltage protection module into a current signal. The analog-to-digital conversion module is used to convert the analog signal into a digital signal for output.

[0062] In this embodiment, the overvoltage protection module uses a 12V / 5A regulated power supply. The voltage regulation range of the overvoltage protection module is 12V. The voltage regulation part is composed of a 7805 three-terminal voltage regulator and an additional current amplification transistor. The potential of its adjustment terminal is raised by the series voltage drop of a voltage stabilizing diode and a light-emitting diode. The overvoltage protection uses the method of short-circuiting the power supply with a thyristor to force the fuse to quickly blow and protect the safety of the subsequent circuit. The blowing time is 1 to 3 microseconds.

[0063] In this embodiment, the signal conditioning module converts the ±3 to 5V voltage signal passing through the overvoltage protection module into a ±2 to 3mA current signal.

[0064] In this embodiment, the model of the analog-to-digital conversion module is AD9252. This module has 8-channel high-speed A / D and 8-channel low-speed A / D, 14 bits, 50MSPS, and a 2k analog-to-digital converter (ADC). This module is powered by a single 1.8V power supply and has an on-chip sample-and-hold circuit. It has the advantages of low price, low power consumption, small size, and ease of use. It uses a 64-pin LFCSP package that complies with the RoHS standard, and the rated temperature range is from -40°C to +85°C industrial temperature range.

[0065] Specifically, the signal processing and storage unit includes a programmable logic unit (FPGA), a clock management unit, and multiple storage units. The programmable logic unit sends the preprocessed and pre-calculated information to the central processing unit MCU through an internal CAN bus interface, and the central processing unit MCU further performs data calculation and processing. It has a 24-channel digital sampling interface inside, and the FPGA performs data preprocessing and logical pre-calculation on the received digital signals. The used FPGA model is XC7Z020 from Xilinx, which consists of six parts: programmable input / output units, programmable logic units, clock management, embedded block RAM, embedded underlying functional units, and embedded dedicated hardware modules. This FPGA can be reused repeatedly without a dedicated programmer, and has the advantages of radiation resistance, high and low temperature tolerance, low power consumption, and high speed. It integrates common functions such as RAM, clock management, and DSP. The synchronous clock encoding inside the FPGA: The high-precision clock generates a time signal with an accuracy of up to the ns level and sends it to the FPGA for accurately calibrating the trigger moment, and making the recorded and stored waveforms carry accurate time stamps. The time signal input is in the 1PPS mode. The synchronous signal receiving circuit directly receives the 1PPS pulse from the GPS synchronous clock. SRAM1-4 inside the FPGA are static random access memories for caching the collected voltage and current signals.

[0066] Specifically, the central processing unit (MCU) is a DSC chip of the STM32f407VG model. The chip has a lot of internal resources, a large storage capacity, and a low price. At the same time, the ARM chip has a wireless communication interface, an Ethernet communication interface, can also generate PWM waves, and can quickly process and output analog quantities, picture information, control signals, alarm signals, etc.

[0067] Specifically, the display unit includes a display screen and several indicator lights, which are respectively connected to the central processing unit CPU through opto-coupler isolation. The used opto-coupler isolation model is TLP112 to ensure the stability and anti-interference of input and output status quantities and analog signal. The display screen is used to display device information, fault information, and line operation information in real time; the indicator lights include a power indicator light, an operation indicator light, a communication indicator light, and a fault indicator light, which are used to indicate the power status, device operation status, communication connection status, and fault information; the power light indicates whether the power supply of the intelligent monitoring device is connected normally. Red indicates abnormal power input, and green indicates normal power input. The operation light indicates whether the intelligent monitoring device is operating normally. Red indicates abnormal operation, and green indicates normal operation. The communication light indicates the communication status of the intelligent monitoring device. It is always off when there is no communication signal, always green when the communication connection is normal, and green flashes when data transmission is in progress. The fault indicator light indicates the fault status. It is always off indicating no fault occurs, and red indicating a fault occurs.

[0068] Specifically, the communication unit includes a remote communication network port and a USB debugging interface. The remote communication network port is an RJ45 network port, which is connected to the remote master station system, sends information to the remote master station system, and receives various instructions from the master station system. The USB debugging interface is connected to an external computer to update the program of the intelligent monitoring device or set fixed value parameters, etc. The RS232 and RS485 interfaces are local communication connection interfaces with other intelligent devices.

[0069] The above are only the preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims

1. An intelligent monitoring method for a high-voltage cable grounding box, characterized in that, It includes the following steps: S1. Collect the current data and voltage data of the protector grounding box; S2. Calculate the resistive current value of the protector grounding box according to the phase relationship between the current data and the voltage data; S3. Judge whether the resistive current value exceeds the first current threshold. If so, go to step S4; otherwise, return to step S1; S4. Judge whether the duration for which the resistive current value exceeds the first current threshold exceeds the set duration. If it exceeds, determine that there is a protector fault and go to step S5; otherwise, go to step S7; S5. Judge whether the resistive current value is less than the second current threshold. If so, determine that a type III fault occurs in the protector grounding box; otherwise, go to step S6; S6. Judge whether the resistive current value is less than the third current threshold. If so, determine that a type II fault occurs in the protector grounding box; otherwise, determine that a type I fault occurs in the protector grounding box; S7. Determine that there is an instantaneous breakdown of the protector, and update the number of instantaneous breakdowns of the protector; S8. Judge whether the number of instantaneous breakdowns of the protector exceeds the set number. If it exceeds, determine that a type I fault occurs in the protector grounding box; otherwise, return to step S1.

2. The intelligent monitoring method for a high-voltage cable grounding box according to claim 1, characterized in that The intelligent monitoring method further includes collecting the current data of the direct grounding box, and judging whether the current value of the direct grounding box exceeds the set threshold. If it exceeds, respond to the grounding loop current alarm; otherwise, continue to collect the current data of the direct grounding box.

3. An intelligent monitoring device for a high-voltage cable grounding box, based on the intelligent monitoring method for a high-voltage cable grounding box described in claim 1, characterized in that, It includes: A protector grounding box, a direct grounding box, an analog quantity acquisition unit, a signal processing and storage unit, a central processing unit, a display unit, and a communication unit; The analog quantity acquisition unit is connected to the protector grounding box and the direct grounding box, and is used for collecting the current data, voltage data of the protector grounding box, and the current data of the direct grounding box; The signal processing and storage unit is connected to the analog quantity acquisition unit, and is used for preprocessing and pre - calculating the collected current data and voltage data; The central processing unit is connected to the signal processing and storage unit, and is used for further calculating and processing the data after preprocessing and pre - calculation to judge the fault information of the line and the grounding box; The display unit is connected to the central processing unit, and is used for displaying the operation information of the device and the line and the fault information of the grounding box; The communication unit is connected to the central processing unit, and is used for connecting to the remote master station system, sending the monitoring information to the remote master station system, and receiving the control instructions issued by the remote master station system.

4. The intelligent monitoring device for a high-voltage cable grounding box according to claim 3, characterized in that, The protector grounding box is connected to the copper shielding layer and the armor layer of the high - voltage cable, and internally includes a protector, a first current sensor, a voltage sensor, a voltage terminal, and a first current terminal. The protector is connected to the grounding wire of the copper shielding layer or the armor layer of the high - voltage cable; the first current sensor is connected in series with the protector and is used for collecting the current signal flowing through the protector; the voltage sensor is connected across the two ends of the protector and is used for collecting the voltage signal across the two ends of the protector; the voltage terminal is respectively connected to the voltage sensor and the analog quantity acquisition unit and is used for transmitting the collected voltage signal to the analog quantity acquisition unit; the first current terminal is respectively connected to the first current sensor and the analog quantity acquisition unit and is used for transmitting the collected current signal to the analog quantity acquisition unit.

5. The intelligent monitoring device for a high-voltage cable grounding box according to claim 3, characterized in that, The direct grounding box is connected to the copper shielding layer and the armor layer of the high-voltage cable, and internally includes a second current sensor and a second current terminal. The second current sensor is connected to the grounding wire of the copper shielding layer or the armor layer of the high-voltage cable and is used to collect the grounding current of the copper shielding layer or the armor layer of the high-voltage cable. The second current terminal is respectively connected to the second current sensor and the analog quantity acquisition unit and is used to transmit the collected current signal to the analog quantity acquisition unit.

6. The intelligent monitoring device for a high-voltage cable grounding box according to claim 3, characterized in that The analog quantity acquisition unit includes an overvoltage protection module, a signal conditioning module, and an analog-to-digital conversion module that are connected in sequence. The overvoltage protection module is used to provide overvoltage protection. The signal conditioning module is used to convert the voltage signal output by the overvoltage protection module into a current signal. The analog-to-digital conversion module is used to convert the analog signal into a digital signal for output.

7. The intelligent monitoring device for a high-voltage cable grounding box according to claim 3, wherein The signal processing and storage unit includes a programmable logic unit, a clock management unit, and multiple storage units. The clock management unit is used to attach a time stamp to the collected signal. The storage unit is used to cache the signal with the time stamp. The programmable logic unit is used to perform preprocessing and pre-operation on the collected signal.

8. The intelligent monitoring device for a high-voltage cable grounding box according to claim 3, characterized in that, The display unit includes a display screen and several indicator lights. The display screen is used to display device information, fault information, and line operation information in real time. The indicator lights include a power indicator light, an operation indicator light, a communication indicator light, and a fault indicator light, which are used to indicate the power status, device operation status, communication connection status, and fault information.

9. The intelligent monitoring device for a high-voltage cable grounding box according to claim 3, characterized in that, The communication unit includes a remote communication network port and a USB debugging interface. The remote communication network port is used to connect to the remote master station system. The USB debugging interface is used to connect to an external computer.

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