Insulation detection method and system for backflow power supply system of rail transit special rail

Abstract

The invention relates to the technical field of rail transit corollary equipment, and discloses an insulation detection method and system for a backflow power supply system of a rail transit special rail. The method comprises the following steps: adaptively determining an on-line detection mode or an off-line detection mode according to a detection part and a detection working condition or a time period of a direct-current traction power supply system for backflow of a rail transit special rail; respectively inputting a first resistor to the ground by a positive electrode and inputting a second resistor to the ground by a negative electrode so as to acquire a first ground sampling voltage and a second ground sampling voltage; simultaneously inputting a first resistor and a second resistor and collecting the voltage of the direct-current system; based on a bridge balance method, according to the first resistance, the second resistance, the first to-ground sampling voltage, the second to-ground sampling voltage and the direct current system voltage, detection values of positive to-ground insulation resistance and negative to-ground insulation resistance are solved; and obtaining an insulation detection result of the direct-current traction power supply system according to a comparison result between the detection values of the positive ground insulation resistance and the negative ground insulation resistance and a preset threshold value. According to the invention, insulation on-line and off-line detection is carried out on the backflow power supply system of the rail transit special rail, the detection time is short, the precision is high, and on-line monitoring and real-time early warning are realized.

Description

Technical Field

[0001] The present invention relates to the technical field of rail transit supporting equipment, and in particular to an insulation detection method and system for a rail transit dedicated rail return power supply system. Background Art

[0002] At present, the subway DC traction power supply system has entered the era of intelligent operation and maintenance. The subway dedicated rail return system has gradually become the design and construction standard for new lines. Insulation performance is one of the most important parameters of electrical equipment. Automatic insulation monitoring has not yet been carried out on the busbars and branches of the power supply system, and the health status assessment model of DC switchgear is still imperfect.

[0003] The normal insulation level of the contact network and return rail of the subway dedicated rail return system to the ground exceeds the MΩ km level. The short-circuit current of the DC grounding fault is small, and the DC circuit breaker cannot act quickly to remove the fault. In addition, there is no fault location method, which leads to a lot of manpower, material resources and time required for fault investigation, seriously affecting the normal operation of the line. It is necessary to further use insulation monitoring instruments to detect and alarm grounding faults, monitor and compare the insulation conditions of the positive and negative poles to the ground of the entire line, and find the insulation weaknesses of the positive and negative poles to the ground as early as possible to assist in formulating more targeted protection measurements. Summary of the invention

[0004] The main purpose of the present invention is to provide an insulation detection method and system for a rail transit dedicated rail return power supply system, aiming to solve at least one of the above-mentioned technical problems.

[0005] To achieve the above object, the present invention provides an insulation detection method for a rail transit dedicated rail return power supply system, comprising:

[0006] Adaptively determine whether the detection mode is an online detection mode or an offline detection mode according to the detection location and detection working condition or time period of the DC traction power supply system of the rail transit dedicated rail return;

[0007] Connecting a first resistor to the ground and a second resistor to the ground with the positive pole of the DC traction power supply system, respectively, to collect a first sampling voltage to the ground and a second sampling voltage to the ground;

[0008] The first resistor and the second resistor are put into use at the same time to collect the DC system voltage;

[0009] Based on the bridge balancing method, according to the first resistor, the second resistor, the first ground sampling voltage, the second ground sampling voltage and the DC system voltage, the detection values ​​of the positive insulation resistance to ground and the negative insulation resistance to ground of the DC traction power supply system are obtained;

[0010] The insulation detection result of the DC traction power supply system is obtained according to the comparison result of the detection value of the positive insulation resistance to ground and the negative insulation resistance to ground with the preset threshold value.

[0011] In some embodiments, the DC traction power supply system is connected to the ground with a first resistor and the negative pole is connected to the ground with a second resistor to collect the first ground sampling voltage and the second ground sampling voltage, including:

[0012] A first resistor is connected between the positive pole of the DC traction power supply system and the ground, so that the first resistor and the positive insulation resistance to ground and the negative insulation resistance to ground of the DC traction power supply system are connected to a detection circuit;

[0013] Collecting a first sampling voltage of the first resistor to ground;

[0014] Disconnect the first resistor and connect a second resistor to the negative pole of the DC traction power supply system, so that the second resistor and the positive insulation resistance to ground and the negative insulation resistance to ground of the DC traction power supply system are connected to the detection circuit;

[0015] A second ground sampling voltage of the second resistor is collected.

[0016] In some embodiments, the detection parts of the DC traction power supply system for rail transit dedicated rail return include: positive bus, feeder outlet, power supply arm or contact network, negative bus or dedicated return rail.

[0017] In some embodiments, obtaining the insulation detection result of the DC traction power supply system according to the comparison result of the detection value of the positive insulation resistance to ground and the negative insulation resistance to ground with a preset threshold value includes:

[0018] If the insulation test result of the positive busbar, feeder outlet, power supply arm or contact network in the test part is that the insulation test has passed, and the insulation test result of the negative busbar or dedicated return rail in the test part is that the insulation test has passed, it is determined that the insulation test result of the DC traction power supply system is normal;

[0019] If the insulation test result of the positive busbar, feeder outlet, power supply arm or contact network insulation is that the insulation test fails, and / or the insulation test result of the negative busbar or dedicated return rail is that the insulation test fails, then it is determined that the insulation test result of the DC traction power supply system is insulation abnormality.

[0020] In some embodiments, obtaining the insulation detection result of the DC traction power supply system according to the comparison result of the detection value of the positive insulation resistance to ground and the negative insulation resistance to ground with a preset threshold value includes:

[0021] Determining a ground insulation detection result of the DC traction power supply system according to a comparison result of the detection value of the ground insulation resistance and a first preset threshold value;

[0022] Determining a negative-to-ground insulation detection result of the DC traction power supply system according to a comparison result of the detection value of the negative-to-ground insulation resistance and a second preset threshold value;

[0023] The insulation detection result of the DC traction power supply system is determined according to the positive insulation detection result to ground and the negative insulation detection result to ground.

[0024] In some embodiments, the determining the ground insulation detection result of the DC traction power supply system according to the comparison result of the detection value of the ground insulation resistance and the first preset threshold value includes:

[0025] If the detected value of the insulation resistance to ground is greater than a first preset threshold, it is determined that the insulation test result of the DC traction power supply system to ground is insulation test passed;

[0026] If the insulation resistance to ground is less than or equal to the first preset threshold, determining that the insulation test result to ground of the DC traction power supply system is insulation test failure;

[0027] Correspondingly, determining the negative-to-ground insulation detection result of the DC traction power supply system according to the comparison result of the detection value of the negative-to-ground insulation resistance and the second preset threshold value includes:

[0028] If the detection value of the negative insulation resistance to ground is greater than a second preset threshold, it is determined that the negative insulation resistance detection result of the DC traction power supply system is insulation test passed;

[0029] If the negative insulation resistance to ground is less than or equal to the second preset threshold, it is determined that the negative insulation resistance to ground of the DC traction power supply system fails the insulation test.

[0030] In some embodiments, the bridge balancing method is used to solve the detection values ​​of the positive insulation resistance to ground and the negative insulation resistance to ground of the DC traction power supply system according to the first resistor, the second resistor, the first sampling voltage to ground, the second sampling voltage to ground and the DC system voltage, including:

[0031] Constructing a first equation based on a bridge balancing method according to the first resistor, the first ground sampling voltage, the DC system voltage, and the positive ground insulation resistance and negative ground insulation resistance of the DC traction power supply system;

[0032] Constructing a second equation based on the bridge balancing method according to the second resistance, the second ground sampling voltage, the DC system voltage, and the positive ground insulation resistance and negative ground insulation resistance of the DC traction power supply system;

[0033] The first equation and the second equation are solved to obtain the detection value of the positive insulation resistance to ground and the detection value of the negative insulation resistance to ground of the DC traction power supply system.

[0034] In some embodiments, the online detection mode is that the measured part and the negative electrode have a rated voltage, and the offline detection mode is that the voltage between the measured part and the negative electrode is 0.

[0035] In addition, to achieve the above-mentioned purpose, the present invention also proposes an insulation detection system for a rail transit dedicated rail return power supply system, comprising:

[0036] A detection mode determination module, used to adaptively determine whether the detection mode is an online detection mode or an offline detection mode according to the detection location and detection working condition or time period of the DC traction power supply system of the rail transit dedicated rail return;

[0037] The resistor input module is used to respectively input a first resistor to the positive pole of the DC traction power supply system and a second resistor to the negative pole of the DC traction power supply system, so as to collect a first sampling voltage to the ground and a second sampling voltage to the ground;

[0038] A resistance simultaneous input module, used for simultaneously inputting the first resistor and the second resistor and collecting the DC system voltage;

[0039] A bridge calculation module, used to solve the detection values ​​of the positive insulation resistance to ground and the negative insulation resistance to ground of the DC traction power supply system according to the first resistor, the second resistor, the first sampling voltage to ground, the second sampling voltage to ground and the DC system voltage based on the bridge balance method;

[0040] The result determination module is used to obtain the insulation detection result of the DC traction power supply system according to the comparison result of the detection value of the positive insulation resistance to ground and the negative insulation resistance to ground with the preset threshold value.

[0041] In addition, to achieve the above-mentioned purpose, the present invention also proposes an electronic device, which includes: a memory, a processor, and an insulation detection program for a rail transit dedicated rail return power supply system stored in the memory and executable on the processor, wherein the insulation detection program for the rail transit dedicated rail return power supply system is configured to implement the insulation detection method for the rail transit dedicated rail return power supply system as described above. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 A schematic diagram of the structure of an electronic device in a hardware operating environment involved in an embodiment of the present invention;

[0043] Figure 2 It is a flow chart of an embodiment of an insulation detection method of a rail transit dedicated rail return power supply system of the present invention;

[0044] Figure 3 It is a schematic diagram of a rail transit dedicated rail return DC traction power supply system involved in an embodiment of the present invention;

[0045] Figure 4 It is a schematic diagram of the insulation detection method of the rail transit dedicated rail return DC traction power supply system involved in the embodiment of the present invention;

[0046] Figure 5 It is a structural block diagram of an embodiment of an insulation detection system of a rail transit dedicated rail return power supply system of the present invention;

[0047] Figure 6 It is a schematic diagram of the implementation steps of the insulation detection system of the rail transit dedicated rail return DC traction power supply system involved in the embodiment of the present invention;

[0048] Figure 7 This is a system block diagram of an insulation detection terminal for a rail transit dedicated rail return DC traction power supply system involved in an embodiment of the present invention;

[0049] Figure 8 A computer program architecture diagram for insulation detection of a rail transit dedicated rail return DC traction power supply system according to an embodiment of the present invention;

[0050] Fig. 9 The present invention is a flowchart of a computer program for insulation detection of a dedicated rail return DC traction power supply system for rail transit involved in an embodiment of the present invention.

[0051] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0052] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0053] It should be noted that all directional indications in the embodiments of the present invention (such as up, down, left, right, front, back, etc.) are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0054] In addition, the descriptions of "first", "second", etc. in the present invention are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the ability of ordinary technicians in the field to implement. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by the present invention. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0055] Reference Figure 1 , Figure 1 The figure is a schematic diagram of the structure of an electronic device of the hardware operating environment involved in the embodiment of the present invention.

[0056] like Figure 1 As shown, the electronic device may include: a processor 1001, such as a central processing unit (CPU), a communication bus 1002, a user interface 1003, a network interface 1004, and a memory 1005. Among them, the communication bus 1002 is used to realize the connection and communication between these components. The user interface 1003 may include a display screen (Display), an input unit such as a keyboard (Keyboard), and the optional user interface 1003 may also include a standard wired interface and a wireless interface. The network interface 1004 may optionally include a standard wired interface and a wireless interface (such as a wireless fidelity (Wireless-Fidelity, Wi-Fi) interface). The memory 1005 may be a high-speed random access memory (Random Access Memory, RAM memory) or a stable non-volatile memory (Non-Volatile Memory, NVM), such as a disk memory. The memory 1005 may also be a storage device independent of the aforementioned processor 1001.

[0057] Those skilled in the art will understand that Figure 1 The structure shown in the figure does not constitute a limitation on the electronic device, and may include more or less components than shown in the figure, or combine certain components, or arrange the components differently.

[0058] like Figure 1 As shown, the memory 1005 as a storage medium may include an operating system, a network communication module, a user interface module, and an insulation detection program for the rail transit dedicated rail return power supply system.

[0059] exist Figure 1In the electronic device shown, the network interface 1004 is mainly used for data communication with a network server; the user interface 1003 is mainly used for data interaction with a user; the processor 1001 and the memory 1005 in the electronic device of the present invention can be set in the electronic device, and the electronic device calls the insulation detection program of the rail transit dedicated rail return power supply system stored in the memory 1005 through the processor 1001, and executes the insulation detection method of the rail transit dedicated rail return power supply system provided in an embodiment of the present invention.

[0060] The present invention provides an insulation detection method, system and equipment for a rail transit dedicated rail return power supply system.

[0061] The embodiment of the present invention provides an insulation detection method for a rail transit dedicated rail return power supply system, referring to Figure 2 , Figure 2 The present invention is a flow chart of an insulation detection method for a rail transit dedicated rail return power supply system according to an embodiment of the present invention.

[0062] like Figure 2 As shown, the insulation detection method of the rail transit dedicated rail return power supply system includes:

[0063] Step S100: Adaptively determine whether the detection mode is an online detection mode or an offline detection mode according to the detection position and detection working condition or time period of the DC traction power supply system of the rail transit dedicated rail return;

[0064] Step S200: a first resistor is connected to the positive pole of the DC traction power supply system and a second resistor is connected to the negative pole of the DC traction power supply system to collect a first sampling voltage to the ground and a second sampling voltage to the ground;

[0065] Step S300: simultaneously inputting the first resistor and the second resistor and collecting the DC system voltage;

[0066] Step S400: obtaining detection values ​​of the positive insulation resistance to ground and the negative insulation resistance to ground of the DC traction power supply system based on the first resistor, the second resistor, the first sampled voltage to ground, the second sampled voltage to ground and the DC system voltage using a bridge balancing method;

[0067] Step S500: Obtaining insulation detection results of the DC traction power supply system according to comparison results of the detection values ​​of the positive insulation resistance to ground and the negative insulation resistance to ground with preset thresholds.

[0068] It should be noted that the execution subject in this embodiment may be an electronic device, which may be a computer device with data processing functions, or other devices that can achieve the same or similar functions. This embodiment does not limit this. In this embodiment, a computer device such as a processor is used as an example for explanation.

[0069] It is understandable that this embodiment is explained by taking the detection method applicable to the DC traction power supply system of the subway dedicated return rail as an example. The subway dedicated return rail system is a power supply system for urban rail transit, which realizes the return of traction current through a dedicated return rail, rather than through a traditional running rail (i.e., the running rail of the subway vehicle). The insulation detection method described in this embodiment, as a supplement to the ground fault protection, is to put the positive resistance of the DC traction power supply system to the ground (housing) into the detection circuit, the negative resistance of the DC traction power supply system to the ground (housing) into the detection circuit, and the positive and negative resistances of the DC system into the detection circuit at the same time, and analyze and calculate the positive insulation resistance to ground and the negative insulation resistance to ground by the bridge balance method, so as to obtain the insulation detection result of the DC system of the subway dedicated return rail. The following is an explanation in conjunction with specific steps.

[0070] In one embodiment, the detection mode is adaptively determined to be an online detection mode or an offline detection mode according to the detection location and detection conditions or time period of the DC traction power supply system for return current of the rail transit dedicated rail.

[0071] In one embodiment, the detection parts of the DC traction power supply system for rail transit dedicated rail return include: a positive busbar, a feeder outlet, a power supply arm or a contact network, a negative busbar or a dedicated return rail.

[0072] Specifically, the online detection mode and the offline detection mode are adaptive according to the differences in the detection locations of the positive busbar, feeder outlet, power supply arm or contact network, negative busbar or dedicated return rail, as well as the differences in the detection conditions or time periods.

[0073] For example, according to the different detection parts of the positive busbar, feeder outlet, power supply arm or contact network, negative busbar or dedicated return rail, and the different detection conditions or time periods, the DC traction power supply system can be tested for insulation online and offline. For example, the subway works in the online detection mode during normal operation during the day, and works in the offline detection mode at night when there is a power outage.

[0074] In one embodiment, the online detection mode is that the measured part and the negative electrode have a rated voltage, and the offline detection mode is that the voltage between the measured part and the negative electrode is 0.

[0075] In one embodiment, the insulation detection result of the DC traction power supply system is obtained according to the comparison result of the detection value of the positive insulation resistance to ground and the negative insulation resistance to ground with the preset threshold value, including: if the insulation detection result of the positive busbar, feeder outlet, power supply arm or contact network in the detection part is that the insulation detection is passed, and the insulation detection result of the negative busbar or dedicated return rail in the detection part is that the insulation detection is passed, then it is determined that the insulation detection result of the DC traction power supply system is normal insulation; if the insulation detection result of the positive busbar, feeder outlet, power supply arm or contact network insulation is that the insulation detection fails, and / or the insulation detection result of the negative busbar or dedicated return rail is that the insulation detection fails, then it is determined that the insulation detection result of the DC traction power supply system is abnormal insulation.

[0076] Specifically, the insulation detection result of the DC traction power supply system is determined according to the insulation detection result of the positive bus, feeder outlet, power supply arm or contact network, and the insulation detection result of the negative bus or dedicated return rail. Exemplarily, it specifically includes: if the insulation detection result of the positive bus, feeder outlet, power supply arm or contact network is that the insulation detection has passed, and the insulation detection result of the negative bus or dedicated return rail is that the insulation detection has passed, then the insulation detection result of the DC traction power supply system is determined to be that the insulation of the system is normal; if the insulation detection result of the positive bus, feeder outlet, power supply arm or contact network is that the insulation detection has failed, and / or the insulation detection result of the negative bus or dedicated return rail is that the insulation detection has failed, then the insulation detection result of the DC traction power supply system is determined to be that the insulation of the system is abnormal.

[0077] It can be understood that in this embodiment, when performing rapid insulation detection on the DC traction power supply system, it is necessary to simultaneously perform insulation detection on the positive bus, feeder outlet, power supply arm or contact network, and negative bus or dedicated return rail of the DC traction power supply system, and only when the insulation detection of both passes can it be determined that the DC traction power supply system has passed this rapid insulation detection. This method of this embodiment can further ensure the comprehensiveness of insulation detection, thereby ensuring the safety of the DC traction power supply system throughout its life cycle. At the same time, when performing insulation detection on various detection parts of the DC traction power supply system, including the positive bus, feeder outlet, power supply arm or contact network, negative bus or dedicated return rail, this embodiment adopts online detection (the voltage between the detected part and the negative pole is 0) and offline detection (the voltage between the detected part and the negative pole is 0) according to different detection parts and different detection conditions or time periods.

[0078] For example, Figure 3 As shown, when the DC traction power supply system incoming switch (such as Figure 3 201 and 202) and the negative switch ( Figure 3 As shown in Figure 2011 and 2021) are in the closed position, all feeder switches ( Figure 3211, 213, 212 and 214) are in the open position, the positive busbar and the negative pole have rated voltage, and the insulation detection adopts the online detection mode; when the incoming switch and the negative pole switch of the DC traction power supply system are in the closed position, the feeder switch is in the closed position, and the corresponding online switch (such as Figure 3 As shown in 2111, 2131, 2121 and 2141) are in the open position, the feeder outlet has a rated voltage with the negative pole, and the insulation detection adopts the online detection mode; when the corresponding online switch of this station is in the open position, the online switch on the opposite side of the same power supply arm or contact network is in the open position, the voltage between the power supply arm or contact network and the negative pole is 0, and the insulation detection adopts the offline detection mode; the negative bus adopts the offline detection mode, in which, Figure 3 2113 and 2124 are cross-zone switches. This embodiment can achieve real-time monitoring while ensuring the insulation detection results, realize early pre-inspection and early warning of various possible insulation faults, reduce the manpower pressure of subway operation and maintenance, reduce the impact of faults on subway operations, and improve the service level of the subway.

[0079] In one embodiment, a first resistor is connected to the ground at the positive pole and a second resistor is connected to the ground at the negative pole of the DC traction power supply system to collect a first sampling voltage to ground and a second sampling voltage to ground, including: connecting a first resistor to the ground at the positive pole of the DC traction power supply system to put the first resistor and the positive insulation resistance and negative insulation resistance of the DC traction power supply system into a detection circuit; collecting a first sampling voltage to ground of the first resistor; disconnecting the first resistor and connecting a second resistor to the ground at the negative pole of the DC traction power supply system to put the second resistor and the positive insulation resistance and negative insulation resistance of the DC traction power supply system into a detection circuit; collecting a second sampling voltage to ground of the second resistor.

[0080] Specifically, first, a resistor (first resistor) is connected to the ground at the positive pole of the DC traction power supply system, so that the first resistor and the positive insulation resistance of the DC traction power supply system to the ground and the negative insulation resistance of the DC traction power supply system to the ground form a positive resistor connection detection circuit, and the ground sampling voltage (first ground sampling voltage) of the positive resistor (first resistor) is collected. Then, the positive resistor (first resistor) of the DC traction power supply system is disconnected, and a resistor (second resistor) is connected to the ground at the negative pole of the DC traction power supply system, so that the second resistor and the positive insulation resistance of the DC traction power supply system to the ground and the negative insulation resistance of the DC traction power supply system to the ground form a negative resistor connection detection circuit, and the ground sampling voltage (second ground sampling voltage) of the negative resistor (second resistor) is collected.

[0081] In one embodiment, the insulation detection result of the DC traction power supply system is obtained according to the comparison result of the detection value of the positive insulation resistance to ground and the negative insulation resistance to ground with a preset threshold, including: determining the positive insulation detection result of the DC traction power supply system according to the comparison result of the detection value of the positive insulation resistance to ground and the first preset threshold; determining the negative insulation detection result of the DC traction power supply system according to the comparison result of the detection value of the negative insulation resistance to ground and the second preset threshold; determining the insulation detection result of the DC traction power supply system according to the positive insulation detection result and the negative insulation detection result.

[0082] Specifically, the positive insulation test result of the DC traction power supply system is determined based on the positive insulation resistance to ground (the detection value of the positive insulation resistance to ground); and the negative insulation test result of the DC traction power supply system is determined based on the negative insulation resistance to ground (the detection value of the negative insulation resistance to ground); the insulation test result of the DC traction power supply system is determined according to the positive insulation test result to ground and the negative insulation test result to ground.

[0083] For example, if the positive insulation test result to ground and the negative insulation test result to ground are insulation test passed, the insulation test result of the DC traction power supply system is that the insulation of the system is normal; otherwise, the insulation test result of the DC traction power supply system is that the insulation of the system is abnormal. In practical applications, how to determine the insulation test result of the DC traction power supply system according to the positive insulation test result to ground and the negative insulation test result to ground can be determined according to different requirements for the positive and negative poles, and generally the requirements for the positive pole are higher.

[0084] It should be noted that, in this embodiment, the detection accuracy of the insulation detection method for the return DC traction power supply system of the rail transit dedicated rail can be adjusted according to the actual working conditions. According to the actual capacitance of the contact network to the ground, the detection time changes when the gear is adjusted. Exemplarily, when performing insulation detection, by calculating the positive insulation resistance to ground and the negative insulation resistance to ground of the DC traction power supply system, the gear adjustment and judgment can be made based on the positive insulation resistance to ground and the negative insulation resistance to ground of the DC traction power supply system. When the input resistance is equivalent to the measured insulation resistance of the DC traction power supply system, the accuracy is relatively high, and 500K, 5M, 20M, 100M resistance multi-gear switching is adopted to make the detection result more accurate. Here, the specific preset input resistance gear and resistance value can be set according to the actual situation, and are not limited to the examples given above. By switching gears and testing, the positive insulation resistance to ground of the DC traction power supply system and the negative insulation resistance to ground of the DC traction power supply system are tested and judged. This method can make the judgment result more accurate, thereby improving the efficiency of subway maintenance work and ensuring the long-term safety and stable operation of the subway.

[0085] In one embodiment, the positive insulation detection result of the DC traction power supply system is determined according to the comparison result between the detection value of the positive insulation resistance and a first preset threshold value, including: if the detection value of the positive insulation resistance is greater than the first preset threshold value, the positive insulation detection result of the DC traction power supply system is determined to be insulation detection passed; if the positive insulation resistance is less than or equal to the first preset threshold value, the positive insulation detection result of the DC traction power supply system is determined to be insulation detection failed; correspondingly, the negative insulation detection result of the DC traction power supply system is determined according to the comparison result between the detection value of the negative insulation resistance and a second preset threshold value, including: if the detection value of the negative insulation resistance is greater than the second preset threshold value, the negative insulation detection result of the DC traction power supply system is determined to be insulation detection passed; if the negative insulation resistance is less than or equal to the second preset threshold value, the negative insulation detection result of the DC traction power supply system is determined to be insulation detection failed.

[0086] Specifically, if the positive and negative insulation resistance to ground is greater than the preset positive and negative insulation resistance threshold to ground, the insulation test result of the DC traction power supply system is determined to be that the system insulation test has passed; if the positive and negative insulation resistance to ground is not greater than the preset positive and negative insulation resistance threshold to ground, the system insulation test result of the DC traction power supply system is determined to be that the system insulation test has failed.

[0087] Exemplarily, if the positive insulation resistance to ground is greater than the preset positive insulation resistance threshold to ground (first preset threshold), and the negative insulation resistance to ground is greater than the preset positive insulation resistance threshold to ground (second preset threshold), then the insulation test result of the DC traction power supply system is determined to be the system insulation test passed; otherwise, the insulation test result of the DC traction power supply system is determined to be the system insulation test failed. According to actual working conditions, the busbar insulation resistance is generally above 5MΩ, and the contact network capacitance to ground is generally greater than 1uF. The preset busbar insulation resistance alarm threshold can be set to 500K. The specific preset insulation resistance threshold can be set according to actual conditions and is not limited to the examples given above.

[0088] It can be understood that in this embodiment, when judging the insulation detection result of the DC traction power supply system, the insulation detection result of the DC traction power supply system can be obtained by comparing the positive and negative insulation resistances to the ground with the preset positive and negative insulation resistance thresholds. If the insulation resistance of the system insulation detection obtained by comparing the positive and negative insulation resistances to the ground with the preset positive and negative insulation resistance thresholds is lower than the threshold, an alarm is processed, and the insulation value is output to the screen display or sent remotely to the superior unit through a communication line. Compared with other mobile insulation detection methods, the method proposed in this embodiment adopts a distributed terminal architecture, which can not only ensure that the insulation detection terminal and the main circuit of the system under test are electrically isolated from each other, and the setting is flexible, but also can realize rapid alarm processing of the insulation value and upload it to the demand end through networking, which can improve the speed of judgment while ensuring the accuracy of the judgment result, thereby improving the efficiency and convenience of subway operation and maintenance.

[0089] In one embodiment, based on the bridge balancing method, according to the first resistor, the second resistor, the first ground sampling voltage, the second ground sampling voltage and the DC system voltage, the detection values ​​of the positive insulation resistance to ground and the negative insulation resistance to ground of the DC traction power supply system are solved, including: based on the bridge balancing method, constructing a first equation according to the first resistor, the first ground sampling voltage, the DC system voltage and the positive insulation resistance to ground and the negative insulation resistance to ground of the DC traction power supply system; based on the bridge balancing method, constructing a second equation according to the second resistor, the second ground sampling voltage, the DC system voltage and the positive insulation resistance to ground and the negative insulation resistance to ground of the DC traction power supply system; solving the first equation and the second equation to obtain the detection value of the positive insulation resistance to ground and the detection value of the negative insulation resistance to ground of the DC traction power supply system.

[0090] Specifically, Figure 4 As shown, first, a resistor R is connected between the positive pole of the DC traction power supply system and the ground (shell). + (first resistor), so that the first resistor R + And the insulation resistance Riso of the DC traction power supply system to ground + , DC traction power supply system negative insulation resistance Riso - Form a positive resistance input detection circuit to collect the positive resistance to ground sampling voltage U + (The first sampling voltage to ground), the formula (the first equation) is obtained:

[0091]

[0092] like Figure 4 As shown, then disconnect the positive pole of the DC traction power supply system from the ground (shell) and connect the first resistor R + , connect the negative pole of the DC traction power supply system to the ground (shell) and connect the resistor R -(second resistor), so that the second resistor R - And the insulation resistance Riso of the DC traction power supply system to ground + , DC traction power supply system negative insulation resistance Riso - , forming a negative resistance input detection circuit, collecting the negative resistance to ground sampling voltage U - (Second sampling voltage to ground), the formula (second equation) is obtained:

[0093]

[0094] like Figure 4 As shown, the positive pole of the DC traction power supply system is connected to the ground (shell) and the first resistor R is connected. + , the negative pole of the DC traction power supply system is connected to the ground (shell) and the second resistor R - , forming positive and negative resistances and simultaneously putting them into the detection circuit to collect the positive resistance to ground sampling voltage U +′ And the negative ground resistance to ground sampling voltage U -′ , find the DC system voltage U:

[0095] U +′ +U -′ =U According to the above formulas (the first equation and the second equation), the insulation resistance Riso of the DC traction power supply system to ground is obtained respectively. + And DC traction power supply system negative insulation resistance Riso - The insulation test result of the DC traction power supply system is obtained by comparing the detection value of the positive and negative insulation resistance to ground with the preset threshold.

[0096] This embodiment designs an insulation detection method suitable for the DC system of the subway dedicated return rail. As a supplement to the ground fault protection, the DC power supply system is subjected to online and offline insulation detection. The subway works in online mode during normal operation during the day and in offline mode during power outages at night. It provides data support for improving the health status model of the current DC switchgear. This function is of great significance for ensuring the safe and stable operation of the subway and improving the quality of subway operation services. By realizing the insulation detection function of the DC system of the subway dedicated return rail, not only can the efficiency of subway maintenance work be improved, but also the impact of faults on subway operations can be reduced, thereby improving the service level of the subway.

[0097] The present embodiment proposes an insulation detection method for a rail transit dedicated rail return power supply system, comprising: adaptively determining whether a detection mode is an online detection mode or an offline detection mode according to a detection location and a detection condition or time period of a DC traction power supply system for rail transit dedicated rail return; respectively inputting a first resistor to the positive pole of the DC traction power supply system and a second resistor to the negative pole of the DC traction power supply system to collect a first ground sampling voltage and a second ground sampling voltage; simultaneously inputting the first resistor and the second resistor and collecting the DC system voltage; based on a bridge balancing method, solving the detection values ​​of the positive insulation resistance to ground and the negative insulation resistance to ground of the DC traction power supply system according to the first resistor, the second resistor, the first ground sampling voltage, the second ground sampling voltage and the DC system voltage; and obtaining the insulation detection result of the DC traction power supply system according to the comparison result of the detection values ​​of the positive insulation resistance to ground and the negative insulation resistance to ground with a preset threshold. In this embodiment, the detection values ​​of the positive insulation resistance to ground and the negative insulation resistance to ground can be obtained by analyzing and calculating through the bridge balance method. According to the different detection parts of the positive busbar, feeder outlet, power supply arm or contact network, negative busbar or special return rail, and the different detection conditions or time periods, online detection mode and offline detection mode are respectively adopted. The insulation detection accuracy can be adjusted in multiple gears according to the actual working conditions. While ensuring the insulation detection results, real-time monitoring is realized, and various possible insulation faults are pre-checked and warned in advance. The detection time is short and the scope of fault protection power outage can be effectively controlled. The online and offline insulation detection of the DC traction power supply system is realized, the detection time is short, and online monitoring and real-time warning can be realized, and the scope of fault protection power outage can be effectively controlled.

[0098] In addition, an embodiment of the present invention further proposes a storage medium, on which is stored an insulation detection program for a rail transit dedicated rail return power supply system. When the insulation detection program for a rail transit dedicated rail return power supply system is executed by a processor, the steps of the insulation detection method for a rail transit dedicated rail return power supply system as described above are implemented.

[0099] Based on the above detection method embodiment, the present invention also provides an insulation detection system for a rail transit dedicated rail return power supply system. Figure 5 , Figure 5 The present invention is a structural block diagram of an insulation detection system for a rail transit dedicated rail return power supply system according to an embodiment of the present invention.

[0100] like Figure 5 As shown, the insulation detection system of the rail transit dedicated rail return power supply system includes:

[0101] A detection mode determination module 10 is used to adaptively determine whether the detection mode is an online detection mode or an offline detection mode according to the detection location and detection working condition or time period of the DC traction power supply system of the rail transit dedicated rail return;

[0102] The resistor input module 20 is used to respectively input a first resistor to the positive pole of the DC traction power supply system and a second resistor to the negative pole of the DC traction power supply system, so as to collect a first sampling voltage to the ground and a second sampling voltage to the ground;

[0103] A resistance simultaneous input module 30, used for simultaneously inputting the first resistor and the second resistor and collecting the DC system voltage;

[0104] A bridge calculation module 40, configured to obtain detection values ​​of the positive insulation resistance to ground and the negative insulation resistance to ground of the DC traction power supply system based on the first resistor, the second resistor, the first sampling voltage to ground, the second sampling voltage to ground and the DC system voltage based on a bridge balancing method;

[0105] The result determination module 50 is used to obtain the insulation detection result of the DC traction power supply system according to the comparison result of the detection value of the positive insulation resistance to ground and the negative insulation resistance to ground with the preset threshold value.

[0106] Specifically, Figure 6 As shown, S1. The insulation detection system of the rail transit dedicated rail return power supply system adopts a distributed terminal architecture. According to the different detection parts of the positive busbar, feeder outlet, power supply arm or contact network, negative busbar or dedicated return rail, as well as the different detection conditions or time periods, the online detection mode and the offline detection mode are adaptive; S2. The insulation detection system of the rail transit dedicated rail return power supply system first inserts a resistor between the positive pole of the DC traction power supply system and the ground, so that it forms a positive resistance input detection loop with the positive insulation resistance of the DC traction power supply system and the negative insulation resistance of the DC traction power supply system to the ground, and collects the sampling voltage of the positive resistance to the ground; S3. Then disconnect the positive pole of the DC traction power supply system and insert the DC The negative pole of the DC traction power supply system is put into resistance to the ground, and it is combined with the positive insulation resistance of the DC traction power supply system to the ground and the negative insulation resistance of the DC traction power supply system to the ground to form a negative resistance input detection circuit, and the negative resistance to ground sampling voltage is collected; S4, finally, the positive pole of the DC traction power supply system is put into resistance to the ground and the negative pole of the DC traction power supply system are put into resistance to the ground at the same time, to form a positive and negative resistance simultaneous input detection circuit to obtain the DC system voltage; S5, the insulation detection system of the rail transit dedicated rail return power supply system respectively obtains the positive insulation resistance and negative insulation resistance of the DC traction power supply system to the ground according to the above-mentioned collected voltages, and obtains the insulation detection result of the DC traction power supply system by comparing the positive and negative insulation resistance detection values ​​with the preset thresholds.

[0107] It should be noted that the implementation steps of the insulation detection system of the rail transit dedicated rail return power supply system can be used to design the insulation detection terminal of the rail transit dedicated rail return DC traction power supply system. The insulation detection terminal may include: memory, processor, relay switching matrix, ADC / DAC converter, high-voltage power supply module, sampling loop, communication module, power supply module and human-machine interface and computer program stored in the memory and running on the processor. The insulation detection terminal adopts a decentralized setting, and the insulation value is quickly processed for alarm and uploaded to the demand side through networking.

[0108] refer to Figure 7 The schematic diagram of the structure of the insulation detection terminal of the rail transit dedicated rail return DC traction power supply system is shown in FIG. Figure 7 As shown, the insulation detection terminal 1 includes: a power supply module 2, an offline measurement sampling circuit 3, an online measurement sampling circuit 4, a relay switching module (relay switching matrix) 5, a processor 6, a communication module 7, a high-voltage power supply 8, a memory 9, a display module (human-machine interface) 10, an ADC digital-to-analog converter 11, a DAC digital-to-analog converter 10, a switch quantity, a button input module 12 and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the steps of the insulation detection method for the rail transit dedicated rail return power supply system as described above are implemented.

[0109] In one example, the processor 6 controls the DAC digital-to-analog converter 10 to output 0-5V to the high-voltage power supply 8 to output an adjustable 0-1000V DC voltage to the insulation detection point. The detection point transmits the sampled voltage to the ADC digital-to-analog converter 11 through the detection sampling network (offline measurement sampling loop 3 or online measurement sampling loop 4). Through the most basic Ohm's law, the processor 6 finally performs data processing and algorithm processing, and transmits the detection results to the upper-level monitoring unit through CAN or RS485, etc., and displays them on the local terminal through the touch screen of the display module (human-machine interface) 10. For example, in order to ensure the accuracy and other performance during the hardware design, high-precision resistors with an accuracy of 0.1%, 16-bit ADC, 12-bit DAC, high-precision low-temperature drift DC high-voltage power supply, high-performance single-chip microcomputer, etc. can be selected.

[0110] It should be noted that the sampling loop in the offline mode and the sampling loop in the online mode in this embodiment are independent of each other. In one example, the offline sampling loop 3 completes the sampling in the offline mode, the computer program controls the high-voltage power supply 8 to output a DC voltage, the positive electrode is connected to the test point through a high-voltage relay, and the negative electrode is connected to the ground through another high-voltage relay. After the offline measurement sampling loop 3 obtains the sampling voltage, it is output to the ADC digital-to-analog converter 11 through the follower operational amplifier, and finally the insulation resistance is converted by the computer program of the processor 6. In another example, the online measurement sampling loop 4 completes the sampling in the online mode, and the high-voltage positive electrode, the high-voltage negative electrode and the ground are switched through the high-voltage relay. In order to ensure the anti-interference performance, a low-pass filter is added to the front end of the operational amplifier to filter out the high-frequency signal of the bus voltage. The follower operational amplifier has the effect of isolation and protection. After low-pass filtering, the online measurement sampling loop 4 obtains the sampling voltage respectively and outputs it to the ADC digital-to-analog converter 11 through the follower operational amplifier, and finally the insulation resistance is converted by the computer program of the processor 6.

[0111] Specifically, in this embodiment, the relay switching module (relay switching matrix) 5 can select a high-power high-voltage reed relay, and the contacts are fully sealed to ensure that the insulation monitor is electrically isolated from the main circuit of the system under test. The drive control of the relay can adopt a circuit combining an optocoupler and a Darlington tube. The Darlington tube is a combination of bipolar transistors, which has the characteristics of high current amplification and low input resistance, and can be used to amplify the current signal output by the optocoupler, thereby driving the operation of the relay. Since there is isolation between the optocoupler and the Darlington tube, interference and noise in the circuit can be effectively prevented, and the stability and reliability of the circuit can be improved.

[0112] In this embodiment, the insulation detection system of the rail transit dedicated rail return DC traction power supply system adopts a distributed terminal architecture, which can not only ensure that the insulation detection terminal is electrically isolated from the main circuit of the system under test, but also avoid crossing the disconnector break and directly connecting to multiple system power supply parts including the positive bus, feeder outlet, power supply arm or contact network, negative bus or dedicated return rail, which conflicts with the concept that the DC traction power supply system must have an intuitive and visible break. The distributed terminal architecture used in this embodiment is easy to install, and each terminal can be flexibly set at various parts of the positive bus, feeder outlet, power supply arm or contact network, negative bus or dedicated return rail of the DC traction power supply system. Through networking, the insulation value can be quickly processed for alarm and uploaded to the demand side.

[0113] It should be noted that, for technical details that are not fully described in the embodiment of the insulation detection system of the rail transit dedicated rail return power supply system, reference can be made to the insulation detection method applied to the rail transit dedicated rail return power supply system as described above provided in any embodiment of the present invention, and will not be repeated here.

[0114] In addition, if Figure 8 As shown, an embodiment of the present invention further proposes a computer program product, including a computer program or an instruction. When the computer program or the instruction is executed by a processor, the steps in the insulation detection method of the rail transit dedicated rail return power supply system described in any one of the above items are implemented. The computer program includes: using human-computer interaction software as the core to realize functions such as operation control and parameter information display, performing insulation detection control in the software interface, and performing other operations such as "self-test" according to the prompt information of the software interface or actual operation requirements. The software displays the insulation detection related parameter information on the screen in the form of lists, names, values, colors, alarm information, etc., based on the valve insulation resistance value calculated by the MCU, key processing operations, etc.

[0115] It should be noted that the computer program of this embodiment uses human-computer interaction software as the core to realize functions such as operation control and parameter information display. The computer program architecture is as follows: Figure 8 Reference Figure 8 , the computer program has the function of operation control. The operator can perform insulation detection control in the software interface through buttons, or perform other operations such as "self-test" according to the prompt information of the software interface or the actual operation requirements. The human-computer interaction software captures, analyzes and processes the operations performed by the operator through the MCU to form control instructions. The control instructions control the control objects such as optocouplers, drivers, relays, DACs, ADCs, high-voltage power supplies, etc. At the same time, the current power-on status and insulation value of the controlled object are displayed on the interface according to the feedback information received by the MCU, thereby realizing human-computer interaction. The computer program has the function of displaying parameter information. The human-computer interaction software displays parameter information to the operator on the screen in the form of lists, names, values, colors, alarm information and other pictures and text through the valve insulation resistance value calculated by the MCU and the key processing operation. In the software interface, the operator can switch the displayed screen and perform other operations through human-computer interaction interfaces such as buttons.

[0116] It can be understood that, in this embodiment, the computer program software running process is as follows Fig. 9As shown. When the insulation detection system (or insulation detection terminal) is turned on, the computer program starts, and the insulation detection system (or insulation detection terminal) performs self-tests, mainly the detection circuit, to detect whether the AD conversion module is working normally, whether there is voltage at the positive and negative poles of the insulation detection contacts, whether the high-voltage power supply module is normal, etc. After the self-test is normal, it waits for the processing of the communication command. If the communication command asks the insulation detection system (or insulation detection terminal) to perform insulation measurement, the insulation detection system (or insulation detection terminal) initiates the insulation measurement. After the measurement is completed, if the insulation resistance is lower than the threshold, an alarm is processed, and the insulation value is output to the screen for display or sent remotely to the superior unit through the communication line. The insulation detection system (or insulation detection terminal) can perform insulation online and offline detection on the DC power supply system. The detection time is short and online monitoring and real-time early warning can be realized, effectively controlling the scope of fault protection power outage.

[0117] It should be understood that the above is only an example and does not constitute any limitation on the technical solution of the present invention. In specific applications, technicians in this field can make settings as needed, and the present invention does not limit this.

[0118] It should be noted that the workflow described above is merely illustrative and does not limit the scope of protection of the present invention. In practical applications, technicians in this field can select part or all of them according to actual needs to achieve the purpose of the present embodiment, and no limitation is made here.

[0119] In addition, it should be noted that, in this article, the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or system including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or system. In the absence of further restrictions, an element defined by the sentence "comprises a ..." does not exclude the existence of other identical elements in the process, method, article or system including the element.

[0120] The serial numbers of the above embodiments of the present invention are only for description and do not represent the advantages or disadvantages of the embodiments.

[0121] Through the description of the above implementation methods, those skilled in the art can clearly understand that the above-mentioned embodiment methods can be implemented by means of software plus a necessary general hardware platform, and of course by hardware, but in many cases the former is a better implementation method. Based on such an understanding, the technical solution of the present invention, or the part that contributes to the prior art, can be embodied in the form of a software product, which is stored in a storage medium (such as a read-only memory (ROM) / RAM, a magnetic disk, or an optical disk), and includes a number of instructions for a terminal device (which can be a mobile phone, a computer, a server, or a network device, etc.) to execute the methods described in each embodiment of the present invention.

[0122] The above are only preferred embodiments of the present invention, and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A method for detecting insulation of a rail transit dedicated rail return power supply system, characterized in that: include: Adaptively determine whether the detection mode is an online detection mode or an offline detection mode according to the detection location and detection working condition or time period of the DC traction power supply system of the rail transit dedicated rail return; Connecting a first resistor to the ground and a second resistor to the ground with the positive pole of the DC traction power supply system, respectively, to collect a first sampling voltage to the ground and a second sampling voltage to the ground; The first resistor and the second resistor are put into use at the same time to collect the DC system voltage; Based on the bridge balancing method, according to the first resistor, the second resistor, the first ground sampling voltage, the second ground sampling voltage and the DC system voltage, the detection values ​​of the positive insulation resistance to ground and the negative insulation resistance to ground of the DC traction power supply system are obtained; The insulation detection result of the DC traction power supply system is obtained according to the comparison result of the detection value of the positive insulation resistance to ground and the negative insulation resistance to ground with the preset threshold value.

2. The method according to claim 1, characterized in that The method of respectively connecting a first resistor to the positive pole of the DC traction power supply system and a second resistor to the negative pole of the DC traction power supply system to the ground, so as to collect a first sampling voltage to the ground and a second sampling voltage to the ground, comprises: A first resistor is connected between the positive pole of the DC traction power supply system and the ground, so that the first resistor and the positive insulation resistance to ground and the negative insulation resistance to ground of the DC traction power supply system are connected to a detection circuit; Collecting a first sampling voltage of the first resistor to ground; Disconnect the first resistor and connect a second resistor to the negative pole of the DC traction power supply system, so that the second resistor and the positive insulation resistance to ground and the negative insulation resistance to ground of the DC traction power supply system are connected to the detection circuit; A second ground sampling voltage of the second resistor is collected.

3. The method according to claim 1, characterized in that The detection parts of the DC traction power supply system for rail transit dedicated rail return include: positive busbar, feeder outlet, power supply arm or contact network, negative busbar or dedicated return rail.

4. The method according to claim 3, characterized in that The step of obtaining the insulation detection result of the DC traction power supply system according to the comparison result of the detection value of the positive insulation resistance to ground and the negative insulation resistance to ground with a preset threshold value includes: If the insulation test result of the positive busbar, feeder outlet, power supply arm or contact network in the test part is that the insulation test has passed, and the insulation test result of the negative busbar or dedicated return rail in the test part is that the insulation test has passed, it is determined that the insulation test result of the DC traction power supply system is normal; If the insulation test result of the positive busbar, feeder outlet, power supply arm or contact network insulation is that the insulation test fails, and / or the insulation test result of the negative busbar or dedicated return rail is that the insulation test fails, then it is determined that the insulation test result of the DC traction power supply system is insulation abnormality.

5. The method according to claim 1, characterized in that The step of obtaining the insulation detection result of the DC traction power supply system according to the comparison result of the detection value of the positive insulation resistance to ground and the negative insulation resistance to ground with a preset threshold value includes: Determining a ground insulation detection result of the DC traction power supply system according to a comparison result of the detection value of the ground insulation resistance and a first preset threshold value; Determining a negative-to-ground insulation detection result of the DC traction power supply system according to a comparison result of the detection value of the negative-to-ground insulation resistance and a second preset threshold value; The insulation detection result of the DC traction power supply system is determined according to the positive insulation detection result to ground and the negative insulation detection result to ground.

6. The method according to claim 5, characterized in that The determining the ground insulation detection result of the DC traction power supply system according to the comparison result of the detection value of the ground insulation resistance and the first preset threshold value includes: If the detected value of the insulation resistance to ground is greater than a first preset threshold, it is determined that the insulation test result of the DC traction power supply system to ground is insulation test passed; If the insulation resistance to ground is less than or equal to the first preset threshold, determining that the insulation test result to ground of the DC traction power supply system is insulation test failure; Correspondingly, determining the negative-to-ground insulation detection result of the DC traction power supply system according to the comparison result of the detection value of the negative-to-ground insulation resistance and the second preset threshold value includes: If the detection value of the negative insulation resistance to ground is greater than a second preset threshold, it is determined that the negative insulation resistance detection result of the DC traction power supply system is insulation test passed; If the negative insulation resistance to ground is less than or equal to the second preset threshold, it is determined that the negative insulation resistance to ground of the DC traction power supply system fails the insulation test.

7. The method according to claim 1, characterized in that The method of obtaining the detection values ​​of the positive insulation resistance to ground and the negative insulation resistance to ground of the DC traction power supply system based on the bridge balancing method according to the first resistor, the second resistor, the first sampling voltage to ground, the second sampling voltage to ground and the DC system voltage includes: Constructing a first equation based on a bridge balancing method according to the first resistor, the first ground sampling voltage, the DC system voltage, and the positive ground insulation resistance and negative ground insulation resistance of the DC traction power supply system; Constructing a second equation based on the bridge balancing method according to the second resistance, the second ground sampling voltage, the DC system voltage, and the positive ground insulation resistance and negative ground insulation resistance of the DC traction power supply system; The first equation and the second equation are solved to obtain the detection value of the positive insulation resistance to ground and the detection value of the negative insulation resistance to ground of the DC traction power supply system.

8. The method according to any one of claims 1 to 7, characterized in that The online detection mode is that the measured part and the negative electrode have a rated voltage, and the offline detection mode is that the voltage between the measured part and the negative electrode is 0.

9. An insulation detection system for a rail transit dedicated rail return power supply system, characterized in that: include: A detection mode determination module, used to adaptively determine whether the detection mode is an online detection mode or an offline detection mode according to the detection location and detection working condition or time period of the DC traction power supply system of the rail transit dedicated rail return; The resistor input module is used to respectively input a first resistor to the positive pole of the DC traction power supply system and a second resistor to the negative pole of the DC traction power supply system, so as to collect a first sampling voltage to the ground and a second sampling voltage to the ground; A resistance simultaneous input module, used for simultaneously inputting the first resistor and the second resistor and collecting the DC system voltage; A bridge calculation module, used to solve the detection values ​​of the positive insulation resistance to ground and the negative insulation resistance to ground of the DC traction power supply system according to the first resistor, the second resistor, the first sampling voltage to ground, the second sampling voltage to ground and the DC system voltage based on the bridge balance method; The result determination module is used to obtain the insulation detection result of the DC traction power supply system according to the comparison result of the detection value of the positive insulation resistance to ground and the negative insulation resistance to ground with the preset threshold value.

10. An electronic device, characterized in that: The electronic device includes: a memory, a processor, and an insulation detection program for a rail transit dedicated rail return power supply system stored in the memory and executable on the processor, wherein the insulation detection program for a rail transit dedicated rail return power supply system is configured to implement an insulation detection method for a rail transit dedicated rail return power supply system as described in any one of claims 1 to 8.

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