Small current grounding line selection verification system and method

Abstract

The application discloses a small-current grounding line selection checking system and method, wherein the small-current grounding line selection checking system comprises a plurality of regional test hosts, and the regional test hosts are in communication connection with a PMS operation and maintenance information management system; the regional test host is in communication connection with a test voltage source and a test current source of a plurality of test points in a region, the test voltage source is in communication connection with the test current source, the test voltage source is electrically connected with a grounding line selection device, the test current source is electrically connected with a bus to be measured, and the grounding line selection device is electrically connected with the bus to be measured. The regional test host arranged in each region can receive the replacement state of the test point grounding line selection device updated by the PMS operation and maintenance information management system in real time, and once a test error occurs, the system gives an alarm, the PMS operation and maintenance information management system updates the test point grounding line selection device state in real time, simultaneously, an operation ticket is distributed to the regional managers, and manual re-inspection is quickly completed.

Description

Technical Field

[0001] This invention relates to a low-current grounding fault location and verification system and method. Background Technology

[0002] In 10kV distribution networks, a neutral-point ungrounded operation mode is typically used. When a single-phase ground fault occurs on a 10kV distribution line, electrical quantities such as zero-sequence current and zero-sequence voltage are generated. The faulty line is selected by the line selection device in the substation, and the signal is sent to the back-end and dispatching terminal. However, due to reasons such as changes in line names, potential hidden dangers in secondary circuits, and possible malfunctions of the line selection device during routine maintenance, the device may fail to correctly select the faulty line, affecting the reliable operation of the power grid.

[0003] Currently, the grounding line selection device is mainly tested using a relay protection tester. The overall operation process is quite cumbersome, and the relay protection tester is not easy to carry and deploy. It is necessary to test each grounding line selection device connected to the busbar in each area one by one, and it is also necessary to conduct manual testing regularly. The workload is large, the cycle is long, and the workload of the testers is extremely heavy. Moreover, when testing different models of grounding line selection devices, the test parameters need to be manually adjusted, making the entire testing process cumbersome. Summary of the Invention

[0004] To address the technical problems of current grounding line selection testing devices being inconvenient to carry and deploy, requiring a large amount of manual testing work, long cycles, and cumbersome operation of the entire testing process due to the need for manual adjustment of test parameters when testing different types of grounding line selection devices, this invention proposes a low-current grounding line selection verification system and method.

[0005] To solve the above problems, the technical solution of the present invention is implemented as follows:

[0006] The low-current grounding fault location verification system disclosed in this application includes several regional test hosts, all of which are communicatively connected to a PMS (Power Management System). Each regional test host is communicatively connected to a test voltage source and a test current source at several test points within its region. The test voltage source and the test current source are also communicatively connected. The test voltage source is electrically connected to a grounding fault location device, and the test current source is electrically connected to the busbar under test. The grounding fault location device is also electrically connected to the busbar under test. The regional test hosts receive real-time updates from the PMS regarding the replacement status of the grounding fault location devices at the test points. The regional test hosts automatically update the corresponding test parameters based on the model of the grounding fault location device, and then transmit the updated test parameters to the test voltage source and test current source within the region, enabling remote manual control testing.

[0007] This application utilizes regional test hosts deployed in various areas to receive real-time updates on the test point grounding fault location device replacement status from the PMS (Power Management System). The regional test hosts automatically update the corresponding test parameters based on the grounding fault location device model, and then transmit the updated test parameters to the test voltage and current sources within the area. This enables remote manual control of testing, and also allows for timed control of the test current sources to synchronously start testing via the test voltage source, achieving multi-test mode operation. This significantly improves the overall efficiency of grounding fault location testing in the distribution network system, reduces manual labor, and triggers a system alarm in case of test errors. The PMS updates the test point grounding fault location device status in real-time and issues operation tickets to management personnel within the area for rapid manual re-inspection.

[0008] Preferably, the test current source includes a first ARM processor, which is electrically connected to a clock module, a communication module, a pulse signal receiver, an LCD display, a power button, and a current conditioning unit. The communication module is communicatively connected to the regional test host and the test voltage source. The pulse signal receiver is electrically connected to the test host through a time synchronization interface. The power button is electrically connected to the current conditioning unit and a battery. The battery is electrically connected to a charging interface. The current conditioning unit is electrically connected to the bus under test.

[0009] Preferably, the current conditioning unit includes an SPWM driver IC chip, a current conditioning circuit, and a multi-channel current output interface. The SPWM driver IC chip is electrically connected to the first ARM processor, the power button, and the current conditioning circuit, respectively. The current conditioning circuit is electrically connected to the multi-channel current output interface.

[0010] Preferably, the current conditioning circuit includes a full-bridge inverter circuit and an LC high-frequency filter circuit. The input terminal of the full-bridge inverter circuit is electrically connected to the power switch and the SPWM driver IC chip, respectively. The output terminal of the full-bridge inverter circuit is electrically connected to the input terminal of the LC high-frequency filter circuit. The output terminal of the LC high-frequency filter circuit is electrically connected to the multi-channel current output interface through a protection resistor and a relay group. The relay group is electrically connected to the first ARM processor.

[0011] Preferably, the test current source further includes a GPS positioning module and a GPS antenna, wherein the GPS positioning module is electrically connected to the first ARM processor and the GPS antenna, respectively.

[0012] Preferably, the test voltage source includes a second ARM processor, which is electrically connected to a clock module, a communication module, a pulse signal receiver, a signal interface, an LCD display, a voltage conditioning unit, and a power button. The communication module is connected to the test current source and the test host. The signal interface is electrically connected to the grounding selection device. The pulse signal receiver is electrically connected to the test host via a time synchronization interface. The power button is electrically connected to the battery and the voltage conditioning unit. The voltage conditioning unit is electrically connected to the grounding selection device.

[0013] Preferably, the voltage conditioning unit includes an SPWM driver IC chip, a voltage conditioning circuit, and a voltage output interface. The SPWM driver IC chip is electrically connected to the second ARM processor, the power button, and the voltage conditioning circuit, respectively. The voltage conditioning circuit and the voltage output interface are electrically connected.

[0014] Preferably, the voltage conditioning circuit includes a full-bridge inverter circuit and an LC high-frequency filter circuit. The input terminal of the full-bridge inverter circuit is electrically connected to the power switch and the SPWM driver IC chip, respectively. The output terminal of the full-bridge inverter circuit is electrically connected to the input terminal of the LC high-frequency filter circuit, and the output terminal of the LC high-frequency filter circuit is electrically connected to the voltage output interface.

[0015] Preferably, the test host includes an MCU, which is electrically connected to a signal interface, a clock module, a communication module, a pulse signal generator, a power button, a setting button, a confirmation button, a test mode selection button, and an LCD display screen. The signal interface is electrically connected to the grounding selection device, the pulse signal generator is electrically connected to the time synchronization interface, the power button is electrically connected to the battery, and the communication module is communicatively connected to the test current source and the test voltage source.

[0016] This application also discloses a method for verifying low-current grounding fault location, including the following steps:

[0017] S1. Obtain the model of the grounding line selection device for each test point in each area;

[0018] S2. Determine the test current parameters and voltage parameters according to the model of each grounding line selection device, and mark the test current parameters, voltage parameters and the model of the grounding line selection device at the test point with a unified feature code;

[0019] S3. Establish a rule base for test parameters of grounding line selection device based on unified feature code;

[0020] S4. If the grounding line selection device is replaced at the test point, the corresponding test current parameters and voltage parameters are found according to the test parameter rule library of the grounding line selection device, and the set parameters are automatically updated according to the corresponding test current parameters and voltage parameters.

[0021] S5. According to the set parameters, the test points in each area will start synchronous grounding selection device testing or manual remote control testing at timed intervals.

[0022] S6. If the test is correct, end the test;

[0023] S7. If the test fails, switch the test loop and repeat step S5 to repeat the test; if the test still fails, enable the alarm; if the test is successful, switch back to the original test loop, repeat step S5 to repeat the test, and if the test still fails, enable the alarm.

[0024] This application identifies the corresponding test current and voltage parameters for different grounding line selection device models within the test points, marks the test current parameters, voltage parameters, and grounding line selection device models with a unified feature code, and establishes a rule base. When a grounding line selection device is replaced at a test point in a certain area, the PMS (Personalized Management System) automatically updates the model of the grounding line selection device at the test points in the area. The area test host automatically updates the set parameters according to the model sent by the system. Once the set parameters are determined, synchronous line selection testing is initiated, greatly improving testing efficiency and eliminating the tedious manual testing of different test points in the area one by one. Furthermore, when a test error occurs, the test voltage source sends an alarm message to the area test host. The area test host then uploads the alarm message to the PMS, which automatically updates the maintenance information. Subsequently, the PMS sends an operation ticket to the management personnel in the area to complete the manual re-inspection and fault elimination of the grounding line selection device in the area.

[0025] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0026] 1. By deploying regional test hosts in each area, the system can receive real-time updates on the test point grounding line selection device replacement status from the PMS operation and maintenance information management system. The regional test hosts automatically update the corresponding test parameters according to the grounding line selection device model, and then transmit the updated test parameters to the test voltage source and test current source in the area. This enables remote manual control of the test, and the test voltage source can also be used to control the test current source to start the test synchronously, realizing multiple test modes. This greatly improves the efficiency of grounding line selection testing in the overall distribution network system, reduces manual input, and if a test error occurs, the system alarms, the PMS operation and maintenance information management system updates the test point grounding line selection device status in real time, and issues operation tickets to the management personnel in the area to quickly complete manual re-inspection.

[0027] 2. By determining the corresponding test current and voltage parameters for different grounding line selection device models within the test points, and marking the test current parameters, voltage parameters, and grounding line selection device models with a unified feature code, and establishing a rule base, when a grounding line selection device is replaced at a test point in a certain area, the PMS operation and maintenance information management system automatically updates the grounding line selection device model of the test points in the area. The area test host automatically updates the set parameters according to the model sent by the system. Once the set parameters are determined, synchronous line selection testing is started, which greatly improves testing efficiency and saves the tedious manual testing of different test points in the area one by one. In case of test errors, the test voltage source sends an alarm message to the area test host. The area test host uploads the alarm message to the PMS operation and maintenance information management system to automatically update the operation and maintenance information. Subsequently, the PMS operation and maintenance information management system sends an operation ticket to the management personnel in the area to complete the manual re-inspection and fault elimination of the grounding line selection device in the area. Attached Figure Description

[0028] Figure 1 This is a system architecture diagram of the present invention;

[0029] Figure 2 This is a schematic diagram illustrating the working principle of the test host, test current source, and test voltage source in this invention.

[0030] Figure 3 This is a flowchart of the process of the present invention. Detailed Implementation

[0031] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0032] Example 1

[0033] like Figure 1-2 As shown, this application discloses a low-current grounding fault location and verification system, including several regional test hosts, all of which are communicatively connected to the PMS (Property Management System). In other words, by deploying multiple regional test hosts connected to the PMS, the real-time forwarding and updating of PMS maintenance information ensures the orderly processing of various maintenance information and helps guide maintenance personnel to operate in a reasonable, orderly, and efficient manner.

[0034] The regional test host is communicatively connected to the test voltage source and test current source of several test points within the region. The test voltage source and the test current source are communicatively connected. The test voltage source is electrically connected to the grounding line selection device. The test current source is electrically connected to the busbar under test. The grounding line selection device is electrically connected to the busbar under test. In other words, the regional test host can send test parameter setting signals to the test voltage source and test current source of each test point in the region in real time. The regional test host also sends various test parameters of the test points to the test voltage source so that the test voltage source can control the test current source to automatically complete the grounding line selection test at a time. The grounding line selection device is electrically connected to the bus under test on the primary side through a zero-sequence current transformer. The zero-sequence current transformer senses the zero-sequence current parameter of the bus under test. By applying a test power supply to the grounding line selection device, the induced current parameter and the externally acquired voltage parameter are used to select the line by comprehensively using the group amplitude and phase comparison method or the harmonic component method. Various line selection parameters are fed back to the locally installed test voltage source in real time. The test voltage source transmits the received line selection parameters remotely to the regional test host in real time. Managers can intuitively understand the line selection parameters of each test point through the regional test host.

[0035] Specifically, the test current source includes a first ARM processor, which is electrically connected to a clock module, a communication module, a pulse signal receiver, an LCD display, a power button, and a current conditioning unit. The communication module is connected to the regional test host and the test voltage source. The pulse signal receiver is electrically connected to the test host through a time synchronization interface. The power button is electrically connected to the current conditioning unit and the battery. The battery is electrically connected to a charging interface. The current conditioning unit is electrically connected to the bus under test. In other words, before using the test current source to connect to the bus to form a test circuit, the test current source should first be synchronized with the test host. In this embodiment, hard synchronization is used, that is, the pulse signal receiver and the synchronization interface are used to complete the serial port synchronization with the test host to improve the accuracy of the subsequent line selection signal of the line selection device. After the test current source is synchronized, the test current source is connected to the primary side outgoing cable to form a test circuit. Then, after the test current source receives the analog current value signal sent by the test host through the wireless communication network, the first ARM processor sends the current conditioning signal to the current conditioning unit to modulate the AC signal with the corresponding parameter value. At the same time, the modulated AC signal parameters are displayed on the LCD screen in real time.

[0036] In some embodiments, the current conditioning unit includes an SPWM driver IC chip, a current conditioning circuit, and a multi-channel current output interface. The SPWM driver IC chip is electrically connected to the first ARM processor, the power button, and the current conditioning circuit, respectively. The current conditioning circuit is electrically connected to the multi-channel current output interface. The current conditioning circuit includes a full-bridge inverter circuit and an LC high-frequency filter circuit. The input terminal of the full-bridge inverter circuit is electrically connected to the power button and the SPWM driver IC chip, respectively. The output terminal of the full-bridge inverter circuit is electrically connected to the input terminal of the LC high-frequency filter circuit. The output terminal of the LC high-frequency filter circuit is electrically connected to the multi-channel current output interface through a protection resistor and a relay group. The relay group is electrically connected to the first ARM processor. In other words, after the first ARM processor receives the analog current value setting signal sent by the test host or test voltage source through the wireless communication network, the first ARM processor sends a modulation signal to the SPWM driver IC chip. The SPWM driver IC chip controls the IGBT switch in the full-bridge inverter circuit to turn on and controls the output AC current value. The output AC signal is filtered by the LC high-frequency filter circuit and then transmitted to the bus cable through the protection resistor via the multi-channel current output interface. At the same time, the first ARM processor controls the relay of the corresponding circuit interface to close. At this time, the current output interface of the corresponding circuit transmits the analog current signal to the bus cable connected to the interface.

[0037] In some embodiments, the test current source further includes a GPS positioning module and a GPS antenna, wherein the GPS positioning module is electrically connected to the first ARM processor and the GPS antenna, respectively. That is, a GPS antenna is also arranged within the test current source, which facilitates the determination of the test bus position in a simulated current test circuit at remote locations. This helps subsequent personnel quickly determine the location of grounding faults based on the test location, thereby improving maintenance efficiency and reducing fault diagnosis time.

[0038] Specifically, the test voltage source includes a second ARM processor, which is electrically connected to a clock module, a communication module, a pulse signal receiver, a signal interface, an LCD display, a voltage conditioning unit, and a power button. The communication module is connected to the test current source and the test host. The signal interface is electrically connected to the grounding selection device. The pulse signal receiver is electrically connected to the test host through a time synchronization interface. The power button is electrically connected to the battery and the voltage conditioning unit. The voltage conditioning unit is electrically connected to the grounding selection device. In other words, before using the test voltage source, it is still necessary to perform time synchronization with the test host. After completing the serial port time synchronization with the test host using the pulse signal receiver and time synchronization interface, the test voltage source is connected to the secondary side grounding fault location device to form a simulated voltage test circuit. At the same time, by comparing the standard simulated voltage value output by the simulated voltage test circuit with the voltage value actually obtained by the grounding fault location device, it can be determined whether there is an abnormality in the secondary side circuit of the grounding fault location device. Meanwhile, the grounding fault location device performs fault location operation by using the group amplitude and phase comparison method based on the obtained simulated voltage signal and the received bus-side transformer induced current signal to determine whether there is a grounding fault on the bus. At the same time, the simulated voltage value is displayed on the LCD screen in real time, and the second ARM processor receives the fault location signal fed back by the grounding fault location device in real time. The second ARM processor processes the received fault location signal and transmits it to the regional test host in real time through the communication module.

[0039] The voltage conditioning unit includes an SPWM driver IC chip, a voltage conditioning circuit, and a voltage output interface. The SPWM driver IC chip is electrically connected to the second ARM processor, the power button, and the voltage conditioning circuit. The voltage conditioning circuit is electrically connected to the voltage output interface. The voltage conditioning circuit includes a full-bridge inverter circuit and an LC high-frequency filter circuit. The input terminals of the full-bridge inverter circuit are electrically connected to the power button and the SPWM driver IC chip. The output terminal of the full-bridge inverter circuit is electrically connected to the input terminal of the LC high-frequency filter circuit. The output terminal of the LC high-frequency filter circuit is electrically connected to the voltage output interface. In other words, after the second ARM processor receives the analog voltage signal sent by the test host via the wireless communication network, the second ARM processor sends a modulation signal to the SPWM driver IC chip. The SPWM driver IC chip controls the IGBT switch in the full-bridge inverter circuit to turn on, controlling the output AC voltage. The output AC voltage signal is filtered by the LC high-frequency filter circuit and then transmitted to the grounding selection device through the voltage output interface.

[0040] Specifically, the test host includes an MCU, which is electrically connected to a signal interface, a clock module, a communication module, a pulse signal generator, a power button, a setting button, a confirmation button, a test mode selection button, and an LCD display screen. The signal interface is electrically connected to the grounding selection device, the pulse signal generator is electrically connected to the time synchronization interface, the power button is electrically connected to the battery, and the communication module is communicatively connected to the test current source and the test voltage source. In other words, before the test current source and test voltage source are connected to the circuit, they should be synchronized with the test host. The test host synchronizes the time with the test current source and test voltage source via serial port. After synchronization, the test current source and test voltage source are connected to the corresponding primary and secondary circuits, respectively. Then, the test host controls the test voltage source to send the set simulated voltage value to the grounding selection device. Subsequently, the test host controls the test current source to send the set simulated current value to the bus cable. During the selection process, the grounding selection device feeds back the acquired selection parameters to the test host in real time. After receiving the set parameter signal sent by the test host, the test voltage source automatically sends a test signal to the test current source according to the test time set by the clock module, thus completing the test of the timed automatic grounding selection device. It should be noted that during manual remote control testing, maintenance personnel can use the setting and confirm keys to set different test parameters for different models of grounding fault location devices, thereby meeting the testing needs of grounding fault location devices from different manufacturers and of different models. At the same time, the test mode selection key can be used to select the corresponding neutral point ungrounded fault mode and the grounding fault through the arc suppression coil test mode, thereby meeting the needs of different test environments.

[0041] Example 2

[0042] like Figure 3 As shown, this application also discloses a method for verifying low-current grounding faults, including the following steps:

[0043] S1. Obtain the grounding line selection device model of each test point in each region. Upload the grounding line selection device model statistics of different test points in different regions to the PMS operation and maintenance information management system. The PMS operation and maintenance information management system stores the data of each grounding line selection device model in the background server, so that the host in each region can retrieve the grounding line selection device model in the test point of the region at any time.

[0044] S2. Based on the model of each grounding line selection device, determine the test current parameters and voltage parameters, and mark the test current parameters, voltage parameters, and grounding line selection device model at the test point with a unified feature code; the regional test host determines the corresponding model's test current parameters and voltage parameters based on the model of each grounding line selection device stored in the PMS operation and maintenance information management system and the expert system set up on the regional test host, and the regional test host establishes a logical relationship between the corresponding model of grounding line selection device, test current parameters, and test voltage parameters, and marks them with a unified feature code.

[0045] S3. Based on the unified feature code, establish a test parameter rule base for the grounding line selection device. The regional test host constructs the test parameter rule base for the grounding line selection device based on the unified feature code and the logical relationship between various models of grounding line selection devices, test current parameters, and voltage parameters.

[0046] S4. If the grounding selection device at the test point is replaced, the corresponding test current and voltage parameters are found according to the grounding selection device test parameter rule library, and the set parameters are automatically updated based on the corresponding test current and voltage parameters. When the grounding selection device at the test point is replaced, the PMS operation and maintenance information management system automatically updates the grounding selection device model at the test point, and sends data update information to the regional test host. The regional test host automatically updates the set parameters of the test point based on the deep learning algorithm combined with the grounding selection device model and the grounding selection device test parameter rule library.

[0047] S5. According to the set parameters, each test point in each area will start synchronous grounding fault location device testing or manual remote control testing at regular intervals. After the parameters are set, the test voltage source in each test point sends a test current setting signal to the test current source, and the grounding fault location testing will start synchronously at each test point at regular intervals. It should be noted that manual remote control testing is also possible. During manual remote control testing, maintenance personnel can use the setting and confirm keys to set different test parameters according to different models of grounding fault location devices, thereby meeting the testing needs of different manufacturers and models of grounding fault location devices. At the same time, the test mode selection key can select the corresponding neutral point ungrounded fault mode and arc suppression coil grounding fault test mode, thereby meeting the needs of different test environments.

[0048] S6. If the test is correct, end the test. When the grounding selection information received by the test voltage source from the grounding selection device matches the simulation information correctly, end the grounding selection test at that test point.

[0049] S7. If the test fails, switch the test loop and repeat step S5 to repeat the test; if the test still fails, activate the alarm; if the test is successful, switch back to the original test loop, repeat step S5 to repeat the test, and if the test still fails, activate the alarm. In other words, when the first loop test fails, the test voltage source sends a loop switching control command to the test current source. The test current source controls the next loop relay to energize and close. At this time, the next loop current output interface is energized to transmit a simulated current signal to the busbar cable under test in that loop. If the busbar selection is still incorrect, the test voltage source sends an alarm signal to the regional test host. The regional test host uploads a fault report for the node grounding selection device to the PMS maintenance information management system. At this time, the PMS maintenance information management system automatically updates the node information and automatically generates an operation ticket, which is then distributed to the regional test point management personnel.

[0050] This specific embodiment is merely an explanation of the present invention and is not intended to limit the invention. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they are within the scope of the claims of the present invention.

Claims

1. A low-current grounding fault location and verification system, characterized in that, The system includes several regional test hosts, all of which are communicatively connected to the PMS (Property Management System). Each regional test host is communicatively connected to a test voltage source and a test current source at several test points within its region. The test voltage source and the test current source are also communicatively connected. The test voltage source is electrically connected to a grounding fault location device, and the test current source is electrically connected to the busbar under test. The grounding fault location device is electrically connected to the primary side busbar under test via a zero-sequence current transformer. The zero-sequence current transformer senses the zero-sequence current parameters of the busbar under test. By applying an external test power supply to the grounding fault location device, the induced current parameters and the externally acquired voltage parameters are used to comprehensively select the fault location using either the group amplitude and phase ratio method or the harmonic component method. All fault location parameters are fed back to the locally installed test voltage source in real time, and the test voltage source remotely transmits the received fault location parameters to the regional test host in real time. The regional test host receives real-time updates on the test point grounding line selection device replacement status from the PMS operation and maintenance information management system. The regional test host automatically updates the corresponding test parameters according to the model of the grounding line selection device, and then transmits the updated test parameters to the test voltage source and test current source in the area to realize manual remote control testing.

2. The low-current grounding fault location and verification system as described in claim 1, characterized in that, The test current source includes a first ARM processor, which is electrically connected to a clock module, a communication module, a pulse signal receiver, an LCD display, a power button, and a current conditioning unit. The communication module is connected to the regional test host and the test voltage source. The pulse signal receiver is electrically connected to the test host through a time synchronization interface. The power button is electrically connected to the current conditioning unit and the battery. The battery is electrically connected to a charging interface. The current conditioning unit is electrically connected to the bus under test.

3. The low-current grounding fault location and verification system as described in claim 2, characterized in that, The current conditioning unit includes an SPWM driver IC chip, a current conditioning circuit, and a multi-channel current output interface. The SPWM driver IC chip is electrically connected to the first ARM processor, the power button, and the current conditioning circuit, respectively. The current conditioning circuit is electrically connected to the multi-channel current output interface.

4. The low-current grounding fault location and verification system as described in claim 3, characterized in that, The current conditioning circuit includes a full-bridge inverter circuit and an LC high-frequency filter circuit. The input terminal of the full-bridge inverter circuit is electrically connected to the power switch and the SPWM driver IC chip, respectively. The output terminal of the full-bridge inverter circuit is electrically connected to the input terminal of the LC high-frequency filter circuit. The output terminal of the LC high-frequency filter circuit is electrically connected to the multi-channel current output interface through a protection resistor and a relay group. The relay group is electrically connected to the first ARM processor.

5. The low-current grounding fault location and verification system as described in claim 2, characterized in that, The test current source also includes a GPS positioning module and a GPS antenna, wherein the GPS positioning module is electrically connected to the first ARM processor and the GPS antenna respectively.

6. The low-current grounding fault location and verification system as described in claim 1 or 2, characterized in that, The test voltage source includes a second ARM processor, which is electrically connected to a clock module, a communication module, a pulse signal receiver, a signal interface, an LCD display, a voltage conditioning unit, and a power button. The communication module is connected to the test current source and the test host. The signal interface is electrically connected to the grounding selection device. The pulse signal receiver is electrically connected to the test host via a time synchronization interface. The power button is electrically connected to the battery and the voltage conditioning unit. The voltage conditioning unit is electrically connected to the grounding selection device.

7. The low-current grounding fault location and verification system as described in claim 6, characterized in that, The voltage conditioning unit includes an SPWM driver IC chip, a voltage conditioning circuit, and a voltage output interface. The SPWM driver IC chip is electrically connected to the second ARM processor, the power button, and the voltage conditioning circuit, respectively. The voltage conditioning circuit and the voltage output interface are electrically connected.

8. The low-current grounding fault location and verification system as described in claim 7, characterized in that, The voltage conditioning circuit includes a full-bridge inverter circuit and an LC high-frequency filter circuit. The input terminal of the full-bridge inverter circuit is electrically connected to the power switch and the SPWM driver IC chip, respectively. The output terminal of the full-bridge inverter circuit is electrically connected to the input terminal of the LC high-frequency filter circuit, and the output terminal of the LC high-frequency filter circuit is electrically connected to the voltage output interface.

9. The low-current grounding fault location and verification system as described in claim 1, characterized in that, The test host includes an MCU, which is electrically connected to a signal interface, a clock module, a communication module, a pulse signal generator, a power button, a setting button, a confirmation button, a test mode selection button, and an LCD display screen. The signal interface is electrically connected to the grounding selection device, the pulse signal generator is electrically connected to the time synchronization interface, the power button is electrically connected to the battery, and the communication module is communicatively connected to the test current source and the test voltage source.

10. A method for verifying low-current grounding fault location, applicable to the low-current grounding fault location verification system as described in any one of claims 1-9, characterized in that, Includes the following steps: S1. Obtain the model of the grounding line selection device for each test point in each area; S2. Determine the test current parameters and voltage parameters according to the model of each grounding line selection device, and mark the test current parameters, voltage parameters and the model of the grounding line selection device at the test point with a unified feature code; S3. Establish a rule base for test parameters of grounding line selection device based on unified feature code; S4. If the grounding line selection device is replaced at the test point, the corresponding test current parameters and voltage parameters are found according to the test parameter rule library of the grounding line selection device, and the set parameters are automatically updated according to the corresponding test current parameters and voltage parameters. S5. According to the set parameters, the test points in each area will start synchronous grounding selection device testing or manual remote control testing at timed intervals. S6. If the test is correct, end the test; S7. If the test fails, switch the test loop and repeat step S5 to repeat the test; if the test still fails, activate the alarm. If the test is successful, switch back to the original test circuit and repeat step S5 to repeat the test. If the test still fails, activate the alarm.

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