DC system insulation monitoring circuit and monitoring method, electronic equipment and storage medium

Abstract

The invention discloses a direct current system insulation monitoring circuit, a monitoring method, electronic equipment and a storage medium, and the circuit comprises a switching bridge module and a balance bridge module which are respectively connected with one side of a built-in protection grounding wire and one side of a built-in protection grounding wire, and are respectively connected with a positive electrode control bus and a negative electrode control bus. One end of the self-checking balance bridge module is connected with a second switch and then is grounded, the other end of the self-checking balance bridge module is connected with a positive electrode control bus and a negative electrode control bus, and one side of the built-in protection grounding wire is further connected with a positive sequence impedance and a negative sequence impedance. The positive sequence impedance is connected with a first control switch and then is connected to a positive pole control bus, the negative sequence impedance is connected with a second control switch and then is connected to a negative pole control bus, the states of different contacts are accurately controlled, effective inspection of a direct current system is achieved, and the simulation grounding fault is controlled. And the line selection accuracy and reliability of the insulation monitoring device are verified.

Description

Technical Field

[0001] The present invention relates to the technical field of power system detection, and in particular to a DC system insulation monitoring circuit, a monitoring method, an electronic device and a storage medium. Background Art

[0002] In modern power systems, the stability and safety of DC systems in substations are crucial. DC systems are usually used to supply power to various control and protection devices in substations. In order to ensure the normal operation of these devices, insulation monitoring devices are widely used to detect and evaluate the insulation status.

[0003] In the related art, the current testing method of insulation monitoring devices still relies on simulating ground faults in the DC system to verify the line selection accuracy of the device. However, this traditional testing method has safety risks, affects the stability of the power system, and has high maintenance costs.

[0004] Therefore, how to test the insulation monitoring device while ensuring the safety and stability of the power system is an urgent problem to be solved. Summary of the invention

[0005] In view of the above problems, the present application provides a DC system insulation monitoring circuit, a monitoring method, an electronic device and a storage medium to at least solve the problems existing in the related art.

[0006] In a first aspect, the present invention provides a DC system insulation monitoring circuit, comprising: a positive control bus, a negative control bus, a switching bridge module, a balancing bridge module, a self-checking balancing bridge module, and a built-in protective grounding wire;

[0007] One side of the built-in protective grounding wire is respectively connected to the switching bridge module and the balancing bridge module, and the switching bridge module and the balancing bridge module are respectively connected to the positive control bus and the negative control bus;

[0008] The other side of the built-in protective grounding wire is connected to a first switch and then grounded;

[0009] One end of the self-checking balancing bridge module is connected to the second switch and then grounded, and the other end is connected to the positive control bus and the negative control bus;

[0010] One side of the built-in protective grounding wire is also connected to a positive sequence impedance and a negative sequence impedance. The positive sequence impedance is connected to the first control switch and then connected to the positive control bus, and the negative sequence impedance is connected to the second control switch and then connected to the negative control bus.

[0011] In one embodiment, the first switch is interlocked with the second switch, and the first control switch and the second control switch are interlocked with the first switch.

[0012] In one embodiment, the switching bridge module includes: a first resistor, a second resistor, a third switch, a fourth switch, a fifth switch and a sixth switch;

[0013] One end of the two first resistors is respectively connected to the built-in protective grounding wire, and the other end is connected to the third switch and then connected to the positive control bus, and connected to the fourth switch and then connected to the negative control bus;

[0014] One end of the two second resistors is respectively connected to the built-in protective grounding wire, and the other end is connected to the fifth switch and then connected to the positive control bus, and is connected to the sixth switch and then connected to the negative control bus.

[0015] In one embodiment, the balancing bridge module includes: a third resistor and a fourth resistor;

[0016] After two third resistors are connected in series, one end is connected to the built-in protective grounding wire, and the other end is connected to the third switch and then connected to the positive control bus, and is grounded between the two third resistors;

[0017] After the two fourth resistors are connected in series, one end is connected to the built-in protective grounding wire, and the other end is connected to the third switch and then connected to the negative control bus, and is grounded between the two fourth resistors.

[0018] In one embodiment, the first switch, the third switch and the fourth switch are normally closed contacts;

[0019] The second switch, the fifth switch, the sixth switch, the first control switch and the second control switch are normally open contacts.

[0020] In a second aspect, an embodiment of the present application provides an electronic device, comprising the DC system insulation monitoring circuit in the first aspect.

[0021] In a third aspect, an embodiment of the present application provides a monitoring method, which is applied to the electronic device in the second aspect, including:

[0022] Obtain monitoring instructions for the DC system;

[0023] Based on the monitoring instruction, the first control switch and the second control switch in the DC system insulation monitoring circuit are controlled to operate so as to simulate a ground fault and obtain a monitoring result.

[0024] In one embodiment, controlling the first control switch and the second control switch in the DC system insulation monitoring circuit based on the monitoring instruction to simulate a ground fault and obtain a monitoring result includes:

[0025] Determining whether the switch is normally closed based on the hard contact signals of the first control switch and the second control switch;

[0026] If it is not normally closed, determine that the switch is faulty.

[0027] In one embodiment, the monitoring method further includes:

[0028] The switching bridge module and the balancing bridge module are self-checked to obtain first detection data and second detection data.

[0029] Determine whether the balancing bridge module is faulty based on the first detection data;

[0030] Whether the switching bridge module is faulty is determined based on the second detection data.

[0031] In a fourth aspect, an embodiment of the present application provides a readable storage medium, on which a program or instruction is stored, and when the program or instruction is executed by a processor, the steps of the monitoring method of the third aspect are implemented.

[0032] Compared with the prior art, one or more embodiments of the above scheme may have the following advantages or beneficial effects:

[0033] The DC system insulation monitoring circuit provided by the present invention comprises: a positive control bus, a negative control bus, a switching bridge module, a balancing bridge module, a self-checking balancing bridge module and a built-in protective grounding wire; one side of the built-in protective grounding wire is respectively connected to the switching bridge module and the balancing bridge module, the switching bridge module and the balancing bridge module are respectively connected to the positive control bus and the negative control bus, the other side of the built-in protective grounding wire is connected to the first switch and then grounded, one end of the self-checking balancing bridge module is connected to the second switch and then grounded, and the other end is connected to the positive control bus and the negative control bus, and one side of the built-in protective grounding wire is also connected to the positive sequence impedance and the negative sequence impedance, the positive sequence impedance is connected to the positive control bus after being connected to the first control switch, and the negative sequence impedance is connected to the negative control bus after being connected to the second control switch, and the effective inspection of the DC system is realized by accurately controlling the states of different contacts, and in the self-checking process, the second switch is closed and the first switch is disconnected, ensuring that the balancing bridge of the device is disconnected from the DC system ground network. The main control CPU verifies the line selection accuracy and reliability of the insulation monitoring device by controlling the first control switch and the second control switch to simulate the grounding fault. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The scope of the present disclosure may be better understood by reading the following detailed description of exemplary embodiments in conjunction with the accompanying drawings. The drawings included are:

[0035] Figure 1 A schematic structural diagram of a DC system insulation monitoring circuit provided in an embodiment of the present application is shown;

[0036] Figure 2 A schematic diagram of a ground fault circuit structure provided by an embodiment of the present application is shown;

[0037] Figure 3 A schematic diagram of a balanced bridge access circuit structure provided in an embodiment of the present application is shown;

[0038] Figure 4 A schematic diagram of a monitoring method provided in an embodiment of the present application is shown;

[0039] Figure 5 An exemplary balanced bridge resistance self-test schematic diagram provided in an embodiment of the present application is shown;

[0040] Figure 6 An exemplary switching bridge resistance self-test schematic diagram provided in an embodiment of the present application is shown;

[0041] Figure 7 An exemplary zeroing self-test schematic diagram provided by an embodiment of the present application is shown;

[0042] Figure 8 A structural block diagram of an electronic device for executing a monitoring method according to an embodiment of the present application is shown;

[0043] Fig. 9 A computer-readable storage medium for storing or carrying a monitoring method according to an embodiment of the present application is shown. DETAILED DESCRIPTION

[0044] In order to make the purpose, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below in conjunction with the accompanying drawings. The described embodiments should not be regarded as limiting the present invention. All other embodiments obtained by ordinary technicians in the field without making creative work are within the scope of protection of the present invention.

[0045] In the following description, reference is made to “some embodiments”, which describe a subset of all possible embodiments, but it will be understood that “some embodiments” may be the same subset or different subsets of all possible embodiments and may be combined with each other without conflict.

[0046] If similar descriptions of "first / second / third" appear in the application documents, the following description is added. In the following description, the terms "first / second / third" are merely used to distinguish similar objects and do not represent a specific ordering of the objects. It is understandable that "first / second / third" can be interchanged in a specific order or sequence where permitted, so that the embodiments of the invention described herein can be implemented in an order other than that illustrated or described herein.

[0047] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which the present invention belongs. The terms used herein are only for the purpose of describing the embodiments of the present invention and are not intended to limit the present invention.

[0048] At present, the test method of the insulation monitoring device still relies on simulating ground faults in the DC system to verify the line selection accuracy of the device. The inventors have found that this traditional test method has the following problems:

[0049] 1. Safety risks: Simulating ground faults in a DC system may cause unnecessary electrical interference in the system and even cause electrical accidents, affecting the safe operation of the DC system.

[0050] 2. Stability issues: Simulated ground faults pose a threat to the stability of the DC system and may cause system anomalies and affect the normal operation of the substation.

[0051] 3. High maintenance cost: Traditional testing methods require frequent simulated fault testing, which not only increases operational complexity but also increases maintenance costs.

[0052] Based on the problems existing in the related art, the present invention provides a DC system insulation monitoring circuit, monitoring method, electronic equipment and storage medium, which no longer needs to simulate ground faults in the DC system, realizes self-inspection of the insulation monitoring device, improves the safety and stability of the system, and reduces maintenance costs.

[0053] See also Figure 1 , Figure 1 A schematic diagram of the structure of a DC system insulation monitoring circuit is provided for an embodiment of the present invention, comprising: a positive control bus, a negative control bus, a switching bridge module, a balancing bridge module, a self-checking balancing bridge module and a built-in protective grounding wire;

[0054] One side of the built-in protective grounding wire is connected to the switching bridge module and the balancing bridge module respectively, and the switching bridge module and the balancing bridge module are connected to the positive control bus and the negative control bus respectively;

[0055] The other side of the built-in protective grounding wire is connected to the first switch and then grounded;

[0056] One end of the self-checking balancing bridge module is connected to the second switch and then grounded, and the other end is connected to the positive control bus and the negative control bus;

[0057] One side of the built-in protective grounding wire is also connected to a positive-sequence impedance and a negative-sequence impedance. The positive-sequence impedance is connected to the first control switch and then connected to the positive control bus, and the negative-sequence impedance is connected to the second control switch and then connected to the negative control bus.

[0058] As an implementation manner, the first switch is interlocked with the second switch, and the first control switch and the second control switch are interlocked with the first switch.

[0059] As an implementation mode, the switching bridge module includes: a first resistor, a second resistor, a third switch, a fourth switch, a fifth switch and a sixth switch;

[0060] One end of the two first resistors is respectively connected to the built-in protective grounding wire, and the other end is connected to the third switch and then connected to the positive control bus, and connected to the fourth switch and then connected to the negative control bus;

[0061] One end of the two second resistors is respectively connected to the built-in protective grounding wire, and the other end is connected to the fifth switch and then connected to the positive control bus, and is connected to the sixth switch and then connected to the negative control bus.

[0062] As an implementation method, the balancing bridge module includes: a third resistor and a fourth resistor;

[0063] After two third resistors are connected in series, one end is connected to the built-in protective grounding wire, and the other end is connected to the third switch and then connected to the positive control bus, and is grounded between the two third resistors;

[0064] After the two fourth resistors are connected in series, one end is connected to the built-in protective grounding wire, and the other end is connected to the third switch and then connected to the negative control bus, and is grounded between the two fourth resistors.

[0065] As an implementation mode, the first switch, the third switch and the fourth switch are normally closed contacts;

[0066] The second switch, the fifth switch, the sixth switch, the first control switch and the second control switch are normally open contacts.

[0067] Specifically, in Figure 1 Among them, R1 and R2 are switching bridge modules, R3 and R4 are balancing bridge modules, PE is the built-in ground wire of the device, which keeps its potential at 0 potential, and R9 is the balancing bridge in the self-test DC system.

[0068] Among them, K1, K3, and K4 are normally closed contacts, and the rest K2, K5, K6, K7, and K8 use normally open contacts. K1 and K2 use an interlocking structure, that is, when K1 is closed, K2 is disconnected, and when K2 is closed, K1 is disconnected, ensuring that no matter what happens in the DC system, there is a set of balancing bridges put into the system.

[0069] Among them, K7 and K8 are interlocked with K1, K1 is disconnected when K7 is closed or K1 is disconnected when K8 is closed; K1 is interlocked with K2, K2 is disconnected when K1 is closed.

[0070] This prevents the device from malfunctioning when K1 is closed and connected to the DC system grounding grid during a simulated grounding fault. When the self-test is started, K2 is closed and K1 is disconnected. The balance bridge is composed of R9, and R1~R4, R+, and R- are all disconnected from the DC system grounding grid. The main control CPU can control the actions of K7 and K8 to simulate a DC system grounding fault and check whether the line selection is accurate and reliable.

[0071] In this embodiment, by accurately controlling the states of different contacts, effective inspection of the insulation monitoring function is achieved. During the self-test process, ensure that R1~R4, R+, and R- are disconnected from the DC system ground network, and the impact of the simulated ground fault on the DC system is minimized. The main control CPU verifies the line selection accuracy and reliability of the insulation monitoring device by controlling K7 and K8 to simulate the ground fault. The design of the interlocking structure (including the interlocking of K7, K8 and K1) effectively prevents false operation and ensures that the device will not be mistakenly connected to the DC system ground network when simulating a ground fault. Therefore, the self-test method has high reliability and accuracy, and can effectively verify the performance of the insulation monitoring device in actual work.

[0072] See also Figure 2 , Figure 2 A schematic diagram of a ground fault circuit structure provided in an embodiment of the present application.

[0073] Figure 2 In the figure, R7 and R8 are grounding simulation resistors.

[0074] See also Figure 3 In order to ensure that there is a set of balancing bridges in the DC system during the ground fault simulation to ensure the stable operation of the DC system, the present application Figure 3 The diagram shows a schematic diagram of a balancing bridge access circuit structure. K2 and K1 are interlocked to ensure that there is only one set of balancing bridges in the DC system under any circumstances. When the self-check starts, K2 is closed and K1 is disconnected to prevent the DC system ground network from being connected to the substation DC system ground network in the event of a ground fault, which would threaten the stable operation of the DC system.

[0075] In some embodiments, the present application provides an electronic device 200, which includes the above-mentioned DC system insulation monitoring circuit.

[0076] In one embodiment, Figure 4 As shown, the present application also provides a monitoring method, which is applied to the above-mentioned electronic device 200, including S110 to S120:

[0077] S110: Obtain monitoring instructions for the DC system.

[0078] S120: Controlling the operation of the first control switch and the second control switch in the DC system insulation monitoring circuit based on the monitoring instruction to simulate a ground fault and obtain a monitoring result.

[0079] In some embodiments, S120 includes: determining whether the switches are normally closed based on hard contact signals of the first control switch (K7) and the second control switch (K8); if not, determining that the switches are faulty.

[0080] In some embodiments, the monitoring method further includes S130 to S150.

[0081] S130: Perform self-test on the switching bridge module and the balancing bridge module to obtain first test data and second test data.

[0082] S140: Determine whether the balancing bridge module is faulty based on the first detection data.

[0083] See also Figure 5 , Figure 5 An exemplary balanced bridge resistance self-test schematic diagram is provided, wherein:

[0084] According to the hard contact signals of switches K1 and K2, it is determined whether the switch is normally closed. If it is not normally closed, it proves that the switch is faulty. After the switch verification is completed, the switch K5 is controlled to close, and a single-pole high-resistance detection resistor Rx is connected to the negative bus of the DC system. On the one hand, it ensures that the voltage U- of the negative bus to the ground is always kept below 55%, and on the other hand, it ensures that the fluctuation difference between the positive and negative bus voltages to the ground is less than 10% of the bus voltage. Since one of the built-in bridge cutting conditions of the insulation monitoring device is that the voltage difference between the positive and negative bus voltages to the ground is greater than 23V, the voltage fluctuation caused by the input of the detection resistor Rx does not exceed 23V, and the bridge cutting action will not be initiated. Then, the resistance value of the detection resistor Rx is known, and the positive bus voltage to the ground U+ and the negative bus voltage to the ground U+ after the detection resistor Rx is put into use are measured. - , the resistance value of the balancing bridge resistor can be calculated by formula 1, and compared with the actual resistance value of the built-in balancing bridge resistor, it can be determined whether the balancing bridge module is faulty or does not meet the usage requirements.

[0085] Formula 1: U+ / (R / / R+)=U- / (R / / Rx / / R-);

[0086] S150: Determine whether the switching bridge module is faulty based on the second detection data.

[0087] See also Figure 6 , Figure 6 An exemplary switching bridge resistance self-test schematic diagram is provided, wherein:

[0088] Control switch K6 to close, and connect single-pole detection resistor Ry to the negative bus of the DC system to trigger the bridge cutting condition of the insulation monitoring device. According to the hard contact signals of switches K3 and K4, determine whether the switch is closed or disconnected normally. If it is not closed or disconnected normally, it proves that the switch is faulty. While verifying the switch, measure the positive bus voltage to ground U1+ and the negative bus voltage to ground U1- after the positive switching bridge resistor Rj is connected, as well as the positive bus voltage to ground U2+ and the negative bus voltage to ground U2- after the negative switching bridge resistor Rj is connected. The resistance value of the detection resistor Ry is known, and the resistance value of the switching bridge resistor is calculated according to the following formula. By comparing the resistance value of the actual built-in switching bridge resistor, it is determined whether the switching bridge module is faulty or does not meet the use requirements.

[0089] Formula 2: U+ / (R / / Rj / / R+)=U- / (R / / Ry / / R-);

[0090] Formula 3: U+ / (R / / R+)=U- / (R / / Rj / / Ry / / R-);

[0091] See also Figure 7 , Figure 7 An exemplary zeroing self-test schematic diagram provided in this application, wherein:

[0092] The device consists of a host, a line selection module and a CT. The purpose of the zero self-test is to check whether the line selection channel of the equipment is normal. This is related to whether the line selection process can select the line correctly. Therefore, by checking the normality of the channel, the faulty channel can be discovered in time, the fault factors can be eliminated, and the channel can be restored to normal.

[0093] exist Figure 7 In the system, the host has a built-in small bus KM to simulate the DC system. When receiving the zeroing command, the host switches the switching bridge from the DC bus to the small bus KM, simulates the grounding fault through the grounding resistor R0, triggers the start of the switching bridge, and sends a characteristic line selection signal. The signal loop is formed by the SIG line and the ground. The signal can be sent and received normally, which proves that the channel is normal, and the indicator light of the channel will light up at the same time. If the channel is abnormal, the CT cannot detect this characteristic line selection signal, and the abnormal situation is fed back to the host, and the zeroing self-test can be completed.

[0094] See also Figure 8 , Figure 8 The present application provides a structural block diagram of an electronic device 200 that can execute the above-mentioned monitoring method. The electronic device 200 can be a smart phone, a tablet computer, a computer, a portable computer or other devices.

[0095] The electronic device 200 further includes a processor 202 and a memory 204. The memory 204 stores a program that can execute the contents of the aforementioned embodiments, and the processor 202 can execute the program stored in the memory 204.

[0096] Among them, the processor 202 may include one or more cores and message matrix units for processing data. The processor 202 uses various interfaces and lines to connect various parts of the entire electronic device 200, and executes various functions and processes data of the electronic device 200 by running or executing instructions, programs, code sets or instruction sets stored in the memory 204, and calling data stored in the memory 204. Optionally, the processor 202 can be implemented in at least one hardware form of digital signal processing (Digital Signal Processing, DSP), field programmable gate array (Field-Programmable Gate Array, FPGA), and programmable logic array (Programmable Logic Array, PLA). The processor 202 can integrate one or a combination of a central processing unit (Central Processing Unit, CPU), a graphics processing unit (Graphics Processing Unit, GPU) and a modulation decoder. Among them, the CPU mainly processes the operating system, user interface and application programs; the GPU is responsible for rendering and drawing display content; and the modem is used to process wireless communications. It can be understood that the above-mentioned modulation decoder may not be integrated into the processor, but may be implemented separately through a communication chip.

[0097] The memory 204 may include a random access memory (RAM) or a read-only memory (ROM). The memory 204 may be used to store instructions, programs, codes, code sets or instruction sets. The memory 204 may include a program storage area and a data storage area, wherein the program storage area may store instructions for implementing an operating system, instructions for implementing at least one function (e.g., instructions for a user to obtain a random number), instructions for implementing the following various method embodiments, etc. The data storage area may also store data (e.g., random numbers) created by the terminal during use, etc.

[0098] The electronic device 200 may also include a network module and a screen. The network module is used to receive and send electromagnetic waves, realize the mutual conversion between electromagnetic waves and electrical signals, and thus communicate with a communication network or other devices, such as communicating with an audio playback device. The network module may include various existing circuit components for performing these functions, such as antennas, radio frequency transceivers, digital signal processors, encryption / decryption chips, user identity modules (SIM) cards, memories, etc. The network module may communicate with various networks such as the Internet, corporate intranets, wireless networks, or communicate with other devices via wireless networks. The above-mentioned wireless networks may include cellular telephone networks, wireless local area networks, or metropolitan area networks. The screen may display interface content and perform data interaction.

[0099] Please refer to Fig. 9 , which shows a block diagram of a computer-readable storage medium provided in an embodiment of the present application. The computer-readable storage medium 400 stores a program code 410, which can be called by a processor to execute the method described in the above method embodiment.

[0100] The computer-readable storage medium 400 may be an electronic memory such as a flash memory, an EEPROM (electrically erasable programmable read-only memory), an EPROM, a hard disk, or a ROM. Optionally, the computer-readable storage medium includes a non-transitory computer-readable storage medium. The computer-readable storage medium 400 has storage space for program codes 410 that perform any method steps in the above method. These program codes 410 can be read from or written to one or more computer program products. The program codes 410 can be compressed, for example, in an appropriate form.

[0101] The embodiment of the present application also provides a computer program product or a computer program, which includes a computer instruction stored in a computer-readable storage medium. The processor of the computer device reads the computer instruction from the computer-readable storage medium, and the processor executes the computer instruction, so that the computer device performs the monitoring method described in the above various optional implementations.

[0102] The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it. Although the present application has been described in detail with reference to the aforementioned embodiments, a person skilled in the art should understand that the technical solutions described in the aforementioned embodiments can still be modified, or some of the technical features can be replaced by equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

[0103] Although the embodiments disclosed in the present invention are as above, the contents described are only embodiments adopted for facilitating the understanding of the present invention and are not intended to limit the present invention. Any technician in the technical field to which the present invention belongs can make any modifications and changes in the form and details of the implementation without departing from the spirit and scope disclosed in the present invention, but the protection scope of the present invention shall still be subject to the scope defined in the attached claims.

Claims

1. A DC system insulation monitoring circuit, characterized in that: include: Positive control bus, negative control bus, switching bridge module, balancing bridge module, self-checking balancing bridge module and built-in protective grounding wire; One side of the built-in protective grounding wire is respectively connected to the switching bridge module and the balancing bridge module, and the switching bridge module and the balancing bridge module are respectively connected to the positive control bus and the negative control bus; The other side of the built-in protective grounding wire is connected to a first switch and then grounded; One end of the self-checking balancing bridge module is connected to the second switch and then grounded, and the other end is connected to the positive control bus and the negative control bus; One side of the built-in protective grounding wire is also connected to a positive sequence impedance and a negative sequence impedance. The positive sequence impedance is connected to the first control switch and then connected to the positive control bus, and the negative sequence impedance is connected to the second control switch and then connected to the negative control bus.

2. The DC system insulation monitoring circuit according to claim 1, characterized in that: The first switch is interlocked with the second switch, and the first control switch and the second control switch are interlocked with the first switch.

3. The DC system insulation monitoring circuit according to claim 2, characterized in that: The switching bridge module comprises: a first resistor, a second resistor, a third switch, a fourth switch, a fifth switch and a sixth switch; One end of the two first resistors is respectively connected to the built-in protective grounding wire, and the other end is connected to the third switch and then connected to the positive control bus, and connected to the fourth switch and then connected to the negative control bus; One end of the two second resistors is respectively connected to the built-in protective grounding wire, and the other end is connected to the fifth switch and then connected to the positive control bus, and is connected to the sixth switch and then connected to the negative control bus.

4. The DC system insulation monitoring circuit according to claim 4, characterized in that: The balancing bridge module comprises: a third resistor and a fourth resistor; After two third resistors are connected in series, one end is connected to the built-in protective grounding wire, and the other end is connected to the third switch and then connected to the positive control bus, and is grounded between the two third resistors; After the two fourth resistors are connected in series, one end is connected to the built-in protective grounding wire, and the other end is connected to the third switch and then connected to the negative control bus, and is grounded between the two fourth resistors.

5. The DC system insulation monitoring circuit according to claim 4, characterized in that: The first switch, the third switch and the fourth switch are normally closed contacts; The second switch, the fifth switch, the sixth switch, the first control switch and the second control switch are normally open contacts.

6. An electronic device, characterized in that: The invention comprises the DC system insulation monitoring circuit according to any one of claims 1 to 5.

7. A monitoring method, applied to the electronic device according to claim 6, characterized in that: The monitoring method comprises: Obtain monitoring instructions for the DC system; Based on the monitoring instruction, the first control switch and the second control switch in the DC system insulation monitoring circuit are controlled to operate so as to simulate a ground fault and obtain a monitoring result.

8. The DC system insulation monitoring circuit according to claim 7, characterized in that: The controlling the first control switch and the second control switch in the DC system insulation monitoring circuit based on the monitoring instruction to simulate a ground fault and obtain a monitoring result includes: Determining whether the switch is normally closed based on the hard contact signals of the first control switch and the second control switch; If it is not normally closed, determine that the switch is faulty.

9. The DC system insulation monitoring circuit according to claim 8, characterized in that: The monitoring method further comprises: Performing self-test on the switching bridge module and the balancing bridge module to obtain first test data and second test data; Determine whether the balancing bridge module is faulty based on the first detection data; Whether the switching bridge module is faulty is determined based on the second detection data.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores program codes, and the program codes can be called by one or more processors to execute the monitoring method as described in any one of claims 7 to 9.

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