Insulation monitoring device with autonomous verification function

Abstract

The utility model provides an insulation monitoring device with an autonomous verification function. The insulation monitoring device comprises a host, a module, a current transformer CT and a DC bus. The host comprises a host CPU, a voltage sampling unit, a double-bridge unit, a first relay, a second relay, a standard voltage source and a communication unit; the module comprises a CT verification unit, a data acquisition unit, a module CPU and a communication unit. The module is connected with the host CPU through a communication unit; and the CT is connected with the module. The insulation monitoring device can verify the CT through the CT verification unit, can control the voltage sampling unit to be connected with the standard voltage source through the relay and verify the sampling precision of the voltage sampling unit, and can control the double-bridge unit to be connected with the standard voltage source through the relay and verify the double-bridge unit. Therefore, when the electronic equipment of the insulation monitoring device is aged or damaged, the electronic equipment can be replaced in time, so that the accuracy and the safety of insulation fault detection of the insulation monitoring device are effectively ensured.

Description

Technical Field

[0001] This application relates to the field of insulation testing of DC systems, and more particularly to an insulation monitoring device with autonomous verification function. Background Technology

[0002] Currently, most DC insulation monitoring devices operating in China use the balanced bridge detection principle. To more accurately detect grounding faults in DC systems, more advanced devices employ a combination of balanced bridge and switching bridge detection principles. Under normal insulation conditions, the positive and negative voltages are essentially balanced. When the insulation of the DC system deteriorates (DC grounding), a deviation occurs in the voltage between the positive and negative poles relative to ground. The device detects this change in voltage relative to ground to trigger a grounding alarm. Simultaneously, due to the voltage difference between the positive and negative poles relative to ground, a DC leakage current is generated in the grounding branch (or an alternating grounding detection signal is generated by the insulation detection device within the system through a shear resistor). This signal is detected by the current transformer (CT) attached to the device, allowing for branch selection.

[0003] However, most DC insulation monitoring devices operating in China have been in operation for several years, even more than a decade. Over time, the electronic components inside these devices age and break down, leading to performance degradation and an inability to accurately detect the condition of insulation equipment. CT aging causes a decrease in current measurement accuracy, resulting in zero-point drift and causing the system to misselect or miss faulty branches. Generally, the switching bridge and the balancing bridge are simultaneously engaged in the DC system. When characteristic signals are needed for line selection, the switching bridge is deactivated. When the balancing bridge fails, it can cause a shift in the voltage between the positive and negative buses to ground, leading to inaccurate calculations of grounding resistance and false alarms, failing to detect grounding at both poles. The positive and negative voltages to ground in the DC system are crucial references for DC monitoring equipment to determine whether a grounding has occurred and for calculating grounding resistance. When the voltage sampling of the monitoring equipment ages and fails, the voltage measurement accuracy decreases, leading to inaccurate system measurements and posing a significant safety hazard to the system. Furthermore, due to the lack of relevant specifications and standards, manufacturers only consider the performance characteristics and anti-interference capabilities of their own products during design, neglecting the comprehensive impact on the system. This results in lagging intelligent design, posing a significant threat to the safe and stable operation of the power system and necessitating regular manual verification. Utility Model Content

[0004] To address the aforementioned issues, this application provides an insulation monitoring device with an autonomous verification function, which enables intelligent verification of internal components with minimal human intervention, ensuring that the insulation monitoring equipment can perform real-time insulation monitoring of the DC power supply system.

[0005] To achieve the objectives of this application, this application provides an insulation monitoring device with autonomous verification function, comprising: a host, a module, a current transformer (CT), and a DC bus; the DC bus is used to connect a DC system and the insulation detection device; the host includes a host CPU, a voltage sampling unit, a dual-bridge unit, a first relay, a second relay, and a standard voltage source; the voltage sampling unit is connected to the DC bus and the standard voltage source respectively through the first relay, and is used to collect the DC bus voltage or to verify whether the voltage sampling unit is damaged; the dual-bridge unit is connected to the DC bus and the standard voltage source respectively through the second relay, and is used to control the connection or disconnection of the bridge resistor in the dual-bridge unit under the control of the host CPU or to verify whether the dual-bridge unit is damaged; the host CPU is connected to the dual-bridge unit and the voltage sampling unit respectively, and is used to acquire the DC bus voltage collected by the voltage sampling unit. The voltage of the line is used to verify whether the sampling accuracy of the voltage sampling unit is qualified, or to verify whether the dual-bridge unit is damaged, or to determine the resistance value of the DC bus to ground based on the acquired voltage, and to determine whether the DC system has an insulation fault based on the resistance value; the module includes a CT verification unit, a module CPU, and a data acquisition unit; the module CPU is connected to the data acquisition unit; the CT verification unit is connected to the CT through a feeder line and is used to verify whether the CT is damaged; the data acquisition unit is used to acquire the leakage current acquired by the CT; the module CPU is used to acquire the leakage current acquired by the data acquisition unit and to verify whether the CT is damaged based on the acquired leakage current; the CT is connected to the module through a feeder line and is used to acquire the leakage current on the feeder line.

[0006] In one possible implementation, the CT verification unit includes a constant voltage source and a switching transistor; the constant voltage source and the switching transistor are connected in series for CT verification; under the control of the switching transistor, the CT verification unit passes through the CT via a standard source feed line, and the CT collects the leakage current on the standard source feed line and uploads it to the data acquisition unit.

[0007] In one possible implementation, the voltage sampling unit is connected to the DC bus and the standard voltage source respectively via the first relay, including: the standard voltage source and the voltage sampling unit are connected via the first relay, wherein the normally closed contact of the first relay is connected to the sampling port of the DC bus, and the normally open contact of the first relay is connected to the standard voltage source; when the normally open contact of the first relay is closed and the normally closed contact is open, the standard voltage source is connected to the voltage sampling unit for verifying whether the voltage sampling accuracy is qualified; when the normally open contact of the first relay is open and the normally closed contact is closed, the voltage sampling unit is connected to the DC system for acquiring the positive and negative DC bus voltages to ground and the DC bus voltage of the DC system.

[0008] In one possible implementation, the dual-bridge unit is connected to the DC bus and the standard voltage source respectively via the second relay, including: the standard voltage source, the dual-bridge circuit, and the DC bus are connected via the second relay, wherein the normally closed contact of the second relay is connected to the sampling port of the DC bus, and the normally open contact of the second relay is connected to the standard voltage source; when the normally open contact of the second relay is closed and the normally closed contact is open, the standard voltage source is connected to the dual-bridge unit for verifying whether the dual-bridge unit is damaged; when the normally open contact of the second relay is open and the normally closed contact is closed, the dual-bridge unit is connected to the DC bus for detecting whether the positive and negative voltages of the DC bus to ground of the DC system have failed.

[0009] In one possible implementation, the dual-bridge unit includes: a balancing bridge and a switching bridge; the balancing bridge and the switching bridge are connected in parallel, wherein the balancing bridge is connected to a second relay via a switch; and the switching bridge is connected to the second relay via a switch.

[0010] In one possible implementation, the insulation monitoring device with autonomous verification function further includes: an artificial balancing bridge module; the artificial balancing bridge module is located between the normally closed switch of the second relay and the DC bus, and is used to protect the stable operation of the DC bus.

[0011] In one possible implementation, the insulation monitoring device with autonomous verification function further includes a communication unit connected to the host CPU for communicating with the module CPU.

[0012] In one possible implementation, the insulation monitoring device with autonomous verification function further includes: an alarm unit connected to the host CPU, used to acquire warning prompts issued by the host when an insulation monitoring fault occurs, as well as warning prompts issued by the voltage sampling unit, the CT and the dual-bridge unit during verification, and to perform corresponding warning operations based on the warning prompts.

[0013] In one possible implementation, the insulation monitoring device with autonomous verification function further includes: a screen connected to the CPU host for displaying the collected leakage current and the collected voltage.

[0014] In one possible implementation, the insulation monitoring device with autonomous verification function further includes a communication module connected to the module CPU for communicating with the host CPU.

[0015] The beneficial effects of this application are:

[0016] This application provides an insulation monitoring device with self-calibration capabilities. It can perform self-calibration on the CTs that collect leakage current in each branch through a CT calibration unit. It can also perform self-calibration on the voltage sampling accuracy of the voltage sampling unit by controlling the voltage sampling unit to connect to a standard voltage source through a first relay, and self-calibrate on the dual-bridge unit by controlling the dual-bridge unit to connect to a standard voltage source through a second relay. This enables the calibration of internal components of electronic equipment, ensuring timely replacement of aging and damaged components. Consequently, it effectively improves the accuracy and safety of insulation fault monitoring when insulation testing equipment performs insulation testing. Attached Figure Description

[0017] The accompanying drawings are provided to further understand this application and form part of the specification. They are used together with the embodiments of this application to explain this application and do not constitute a limitation thereof.

[0018] Figure 1 This is a schematic diagram of the structure of a conventional insulation monitoring device provided in an embodiment of this application;

[0019] Figure 2 A circuit diagram of an insulation monitoring device with autonomous verification function provided in this application embodiment;

[0020] Figure 3 A diagram showing the connection between the CT and modules in an insulation monitoring device with self-calibration function, provided in an embodiment of this application;

[0021] Figure 4 A detailed schematic diagram of the CT verification unit in an insulation monitoring device with autonomous verification function provided in this application embodiment;

[0022] Figure 5 A circuit diagram for voltage sampling and voltage sampling accuracy verification in a host provided in an embodiment of this application;

[0023] Figure 6 The circuit diagram for bridge resistance acquisition and bridge resistance verification in the host provided in the embodiments of this application;

[0024] Figure 7 A flowchart illustrating the bridge resistance verification process in an insulation monitoring device with autonomous verification function, provided as an embodiment of this application. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0026] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature; in the description of this application, unless otherwise stated, "multiple" means two or more.

[0027] The embodiments of this application will be further described below with reference to the accompanying drawings.

[0028] Figure 1 The present application provides a schematic diagram of the structure of an existing insulation monitoring device. The device includes: a host, several modules and several current transformers. The host and several modules are connected, and each module is connected to several current transformers. The host is connected to several current transformers through each module for insulation fault detection.

[0029] Figure 2 The circuit diagram of an insulation monitoring device with autonomous verification function provided in this application embodiment is used for verifying the voltage sampling unit, verifying the dual-bridge unit, and detecting insulation faults. It includes: a host, a module, a current transformer (CT), and a DC bus.

[0030] The host includes a host CPU, a voltage sampling unit, a dual-bridge unit, a first relay, a second relay, a standard voltage source, and a communication unit;

[0031] The host CPU is connected to the dual-bridge unit and the voltage sampling unit respectively. The host CPU is used to generate control signals in response to detection commands or verification commands.

[0032] The voltage sampling unit is connected to the DC bus and the standard voltage source via a first relay, and is used to collect the DC bus voltage or to verify whether the voltage sampling unit is damaged; the dual-bridge unit is connected to the DC bus and the standard source voltage via a second relay, and is used to adjust the resistance value connected to the DC system according to the control signal or to verify whether the dual-bridge unit is damaged.

[0033] The module includes a CT verification unit, a data acquisition unit, a module CPU, and a communication unit; the module is connected to the host CPU via the communication unit for data communication.

[0034] The CT is connected to the module to collect the CT verification current signal emitted by the CT verification unit or to collect the leakage current on the feeder.

[0035] refer to Figure 3 , Figure 4 As shown, Figure 3 This application provides a diagram showing the connection between a CT and a module in an insulation monitoring device with self-calibration function. The module is connected to multiple CTs, and the feeder for calibration passes through all the CTs corresponding to the module and is in the same direction. Figure 4 This is a detailed schematic diagram of a CT verification unit in an insulation monitoring device with autonomous verification function, provided in an embodiment of this application, used to verify whether the CT is damaged.

[0036] Specifically, the constant voltage source U is connected in series with the switching transistor K. Under the control of the switching transistor K, the calibration unit and the CT are connected in series through the standard source feeder.

[0037] Specifically, the CT verification unit outputs a verification signal, which passes through each CT via a feeder. The CT collects the leakage current on the standard source feeder and uploads it to the data acquisition unit.

[0038] The module CPU acquires the current signal from the data acquisition unit, compares the current difference acquired by the CT before and after the switching transistor K is turned on with the verification current I output by the verification unit, and determines whether the CT is qualified.

[0039] Where I = U / R. If, outside the allowable error range, the current difference collected by the CT before and after the switching transistor K is turned on is not equal to the value of I, it indicates that the CT is damaged and needs to be replaced.

[0040] After the CT verification is completed, the switch is reset and disconnected.

[0041] Figure 5The voltage sampling and voltage sampling accuracy verification circuit diagram provided in this application embodiment is used to verify the voltage sampling accuracy and acquire the DC bus voltage. The voltage sampling unit is connected to a standard voltage source through a first relay. The normally closed contact of the first relay is connected to the DC bus sampling port, and the normally open contact of the first relay is connected to the standard voltage source. When the normally open contact of the first relay is closed and the normally closed contact is open, the standard voltage source is connected to the voltage sampling unit to verify whether the voltage sampling accuracy is qualified. When the normally open contact of the first relay is open and the normally closed contact is closed, the voltage sampling unit is connected to the DC bus to acquire the positive and negative DC bus voltages to ground and the DC bus voltage.

[0042] Specifically, in conjunction with the standard voltage source to verify the voltage sampling accuracy, a standard voltage source U1 is designed in the host, and a relay I is designed. Ki-3 and Ki-4 are normally closed contacts of relay I connected to the DC bus sampling port. Ki-1 and Ki-2 are normally open contacts of relay I connected to the standard voltage source U1. RA, RB, Ra, and Rb are the protection resistor and proportional resistor of the voltage sampling unit, respectively. ab is the sampling port of voltage sampling. Uab is proportional to the two ends of the sampling circuit U1', and the ratio is (Ra+Rb):(RA+RB+Ra+Rb).

[0043] Specifically, when the monitoring device is working normally, relay I is not activated, and the voltage sampling unit collects the bus voltage in the DC bus. When voltage sampling verification is required, the relay activates, Ki-3 and Ki-4 are disconnected, and Ki-1 and Ki-2 are closed, disconnecting the voltage sampling unit from the DC bus and connecting it to the built-in standard source circuit. The standard source U1 outputs a DC voltage of 24V. The insulation monitoring device measures the voltage Uab between points a and b, and calculates U1' through a proportional amplifier circuit. By comparing the calculated voltage U1' with the 24V output from the standard source, it is determined whether the voltage sampling accuracy is qualified.

[0044] After the verification is completed, reset all the active switches to allow the voltage sampling unit to be reconnected to the DC bus, and output and display the verification results.

[0045] Optionally, the calibration of the balanced bridge and switching bridge must be carried out when the voltage sampling accuracy is qualified and the insulation of the two stages of the DC system is good, so as to avoid safety accidents due to grounding faults in the system during the test.

[0046] Figure 6The circuit diagram for bridge resistance measurement and verification in the host provided in this application embodiment is used for insulation fault detection and verification of whether the bridge resistance is damaged. The dual-bridge unit is connected to the DC bus and the standard voltage source respectively through a second relay, including: a standard voltage source, a dual-bridge circuit, and the DC bus connected through the second relay. The normally closed contact of the second relay is connected to the sampling port of the DC bus, and the normally open contact of the second relay is connected to the standard voltage source. When the normally open contact of the second relay is closed and the normally closed contact is open, the internal standard source is connected to the dual-bridge unit to verify whether the dual-bridge unit is damaged. When the normally open contact of the second relay is open and the normally closed contact is closed, the dual-bridge unit is connected to the DC bus to detect whether the positive and negative voltages of the DC bus to ground of the DC system have failed.

[0047] Specifically, the balancing bridge and switching bridge of the insulation device are connected to the DC system through the normally closed contacts Kj-3 and Kj-4 of relay J. Kj-1 and Kj-2 are connected to the standard source U1 after the normally open contacts of relay J are closed. R1 and R2 are the balancing bridge of the insulation monitoring device, and R3 and R4 are the switching bridge of the insulation device. The corresponding normally closed switches K1 to K4 ensure that the bridge resistance is connected to the DC system when the insulation monitoring device is working normally. R5 and R6 are the artificial balancing bridges temporarily put into operation during verification to ensure the stable operation of the DC system. The normally open switches K5 and K6 control the putting into and taking out of the artificial balancing bridges.

[0048] like Figure 7 As shown, a flowchart for verifying a dual-bridge unit is provided. Before verification, it is confirmed that the voltage sampling accuracy of the insulation monitoring system is qualified and the positive and negative insulation of the DC system to ground is good.

[0049] Specifically, during the verification process, step 1: close switches K5 and K6 to connect the artificial balancing bridge R5 and R6 to the DC system, and monitor and confirm that the positive and negative voltages to ground of the DC system are approximately equal after the artificial balancing bridge is connected.

[0050] Step 2: Relays J2 and J1 activate, Kj-3 and Kj-4 of the second relay disconnect, and Kj-1 and Kj-2 close, causing the balanced bridge and switching bridge to exit the DC bus and be switched to the built-in standard source circuit; at the same time, Ki-3 and Ki-4 of the relay disconnect, and Ki-1 and Ki-2 close, and the voltage sampling circuit is also disconnected from the DC system and switched to the built-in standard source circuit.

[0051] Optionally, as can be seen from U+ / U-=R+ / R-, the positive and negative ground voltages U+ / U- are proportional to the positive and negative ground resistances R+ / R- of the system. After the built-in standard source circuit is put into operation, the ground resistances R+ and R- of the standard source circuit can be regarded as being composed of the balanced bridge R1 and R2 and the switching bridge R3 and R4. When the bridge resistance is normal, R+=R-. After the bridge resistance is removed, the fluctuation of the ground voltages U+ and U- will inevitably change.

[0052] Step 3: During the verification, disconnect K1, K2, K3, and K4 one by one to remove the corresponding bridge resistors. Monitor the voltage change through the voltage sampling circuit and observe the system voltage fluctuation. If there is no voltage change when disconnected, it indicates that the bridge resistor is damaged.

[0053] Step 4: Reset all switches and output the test results. The insulation monitoring device will determine whether maintenance is required and issue an alarm based on the test results.

[0054] In this embodiment, the insulation detection device with autonomous verification function also includes an alarm module. The alarm module is connected to the host CPU and is used to obtain the warning prompts issued by the host CPU when an insulation monitoring fault occurs, as well as the warning prompts issued when the voltage sampling unit, CT and dual-bridge unit are verified. The host CPU performs the corresponding warning operation according to the warning prompt to ensure that the insulation detection device works normally.

[0055] In this embodiment, the insulation detection device with autonomous verification function further includes a communication unit connected to the host CPU for communicating with the module CPU.

[0056] In this embodiment, the insulation detection device with autonomous verification function further includes a communication unit connected to the module CPU for communicating with the host CPU.

[0057] In this embodiment of the application, the insulation monitoring device with self-verification function also includes a screen, which is connected to the CPU host and is used to display the collected leakage current and the collected voltage.

[0058] The beneficial effects of using the embodiments of this application are as follows:

[0059] This application provides an insulation monitoring device with autonomous verification function, comprising: a main unit, a module, a current transformer (CT), and a DC bus; the main unit includes a main CPU, a voltage sampling unit, a dual-bridge unit, a first relay, a second relay, and a standard voltage source; the module includes a CT verification unit, a data acquisition unit, and a module CPU; the DC bus is used to connect the DC system and the insulation monitoring device; the module and the main CPU are connected via a communication unit for data communication; the CT is connected to the module via a feeder line for collecting leakage current on the feeder line. Through the insulation monitoring device provided in this application, the CT verification unit can autonomously verify the CT collecting leakage current in each branch; the first relay can control the voltage sampling unit to connect to the standard voltage source to autonomously verify the voltage sampling accuracy of the voltage sampling unit; and the second relay can control the dual-bridge unit to connect to the standard voltage source to autonomously verify the dual-bridge unit. This enables the verification of internal components of electronic equipment, ensuring timely replacement of aging and damaged internal components, thereby effectively improving the accuracy and safety of insulation fault monitoring during insulation testing.

[0060] In the embodiments provided in this application, it should be understood that the disclosed systems, modules, and methods can be implemented in other ways. For example, the module embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces, or indirect coupling or communication connection between modules or units, and may be electrical, mechanical, or other forms.

[0061] The above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit it. This application is not limited to the exact structures described above and illustrated in the accompanying drawings, and it should not be considered that the specific implementation of this application is limited to these descriptions. For those skilled in the art, various changes and modifications made without departing from the concept of this application should be considered to fall within the protection scope of this application.

Claims

1. An insulation monitoring device with autonomous verification function, characterized in that, include: Main unit, modules, current transformers (CTs), DC bus; The DC bus is used to connect the DC system and the insulation detection device; The host includes a host CPU, a voltage sampling unit, a dual-bridge unit, a first relay, a second relay, and a standard voltage source. The voltage sampling unit is connected to the DC bus and the standard voltage source via the first relay, and is used to collect the DC bus voltage or to verify whether the voltage sampling unit is damaged. The dual-bridge unit is connected to the DC bus and the standard voltage source via the second relay, and is used to control the connection or disconnection of the bridge resistor in the dual-bridge unit under the control of the host CPU, or to verify whether the dual-bridge unit is damaged. The host CPU is connected to both the dual-bridge unit and the voltage sampling unit, and is used to acquire the DC bus voltage collected by the voltage sampling unit, verify whether the sampling accuracy of the voltage sampling unit is qualified based on the acquired voltage, or verify whether the dual-bridge unit is damaged based on the acquired voltage, or determine the resistance value of the DC bus to ground based on the acquired voltage, and determine whether an insulation fault has occurred in the DC system based on the resistance value. The module includes a CT verification unit, a module CPU, and a data acquisition unit; the module CPU is connected to the data acquisition unit; the CT verification unit is connected to the CT via a feeder line and is used to verify whether the CT is damaged; the data acquisition unit is used to acquire the leakage current acquired by the CT; the module CPU is used to acquire the leakage current acquired by the data acquisition unit and verify whether the CT is damaged based on the acquired leakage current; The CT is connected to the module via a feeder line and is used to collect the leakage current on the feeder line.

2. The insulation monitoring device with autonomous verification function according to claim 1, characterized in that... include: Constant voltage source and switching transistor; The constant voltage source and the switching transistor are connected in series to perform the CT verification; Under the control of the switching transistor, the CT verification unit passes through the CT via a standard source feeder. The CT collects the leakage current on the standard source feeder and uploads it to the module CPU. The module CPU then obtains the leakage current for comparison.

3. The insulation monitoring device with autonomous verification function according to claim 1, characterized in that, The voltage sampling unit is connected to the DC bus and the standard voltage source respectively through the first relay, including: The standard voltage source and the voltage sampling unit are connected through the first relay. The normally closed contact of the first relay is connected to the DC bus sampling port, and the normally open contact of the first relay is connected to the standard voltage source. When the normally open contact of the first relay is closed and the normally closed contact is open, the standard voltage source is connected to the voltage sampling unit to verify whether the voltage sampling accuracy is qualified. When the normally open contact of the first relay is open and the normally closed contact is closed, the voltage sampling unit is connected to the DC system to collect the positive and negative DC bus voltages to ground and the DC bus voltage of the DC system.

4. The insulation monitoring device with autonomous verification function according to claim 1, characterized in that, The dual-bridge unit is connected to the DC bus and the standard voltage source respectively via the second relay, including: The standard voltage source, the dual-bridge unit, and the DC bus are connected via the second relay. The normally closed contact of the second relay is connected to the sampling port of the DC bus, and the normally open contact of the second relay is connected to the standard voltage source. When the normally open contact of the second relay is closed and the normally closed contact is open, the standard voltage source is connected to the dual-bridge unit to verify whether the dual-bridge unit is damaged. When the normally open contact of the second relay is open and the normally closed contact is closed, the dual-bridge unit is connected to the DC bus to detect whether a fault has occurred in the positive and negative voltages to ground of the DC bus in the DC system.

5. The insulation monitoring device with autonomous verification function according to claim 4, characterized in that, The dual-bridge unit includes: a balancing bridge and a switching bridge; The balancing bridge is connected in parallel with the switching bridge, wherein the balancing bridge is connected to the second relay via a switch; the switching bridge is connected to the second relay via a switch.

6. The insulation monitoring device with autonomous verification function according to claim 1, characterized in that, It also includes: an artificial balancing bridge module; The artificial balancing bridge module is located between the normally closed switch of the second relay and the DC bus, and is used to protect the stable operation of the DC power supply.

7. The insulation monitoring device with autonomous verification function according to claim 1, characterized in that, The host also includes a communication unit connected to the host CPU for communicating with the module CPU.

8. An insulation monitoring device with autonomous verification function according to claim 1, characterized in that, Also includes: An alarm unit, connected to the host CPU, is used to acquire warning prompts issued by the host when an insulation monitoring fault occurs, as well as warning prompts issued by the voltage sampling unit, the CT, and the dual-bridge unit during verification. The host CPU performs corresponding warning operations based on the warning prompts.

9. An insulation monitoring device with autonomous verification function according to claim 1, characterized in that, Also includes: The screen, connected to the CPU host, is used to display the collected leakage current and the collected voltage.

10. The insulation monitoring device with autonomous verification function according to claim 1, characterized in that, The module further includes a communication module connected to the module CPU for communicating with the host CPU.

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