Ground fault hierarchical detection and positioning system for monorail vehicles

Abstract

The present invention provides a grounding fault grading detection and location system applicable to monorail vehicles. The fault detection unit includes: a voltage sensor disposed between the negative busbar and the vehicle body for detecting the voltage V between the negative busbar and the vehicle body; a data acquisition unit for acquiring the voltage value detected by the voltage sensor, and a fault analysis unit for analyzing and locating the grounding fault of the monorail vehicle according to the voltage value acquired by the data acquisition unit: if V2 < V ≤ V3, the fault occurs between the train AC380V system and the vehicle body, or between the AC220V system and the vehicle body; if V1 < V < V2, the fault occurs between the DC110V system and the vehicle body. Further, by combining the current values detected by the pantograph current sensor, the auxiliary power supply box current sensor, and the traction inverter box current sensor, the location of the grounding fault is determined. This system automatically locks the system and equipment where the grounding fault occurs by adding some on-vehicle voltage and current sensors on the train and comparing and analyzing the acquired voltage and current values.

Description

Technical Field

[0001] The present invention relates to the technical field of rail transportation, and in particular to a ground fault hierarchical detection and positioning system suitable for monorail vehicles. Background Art

[0002] Monorail vehicles rely on rubber tires to travel on track beams. Unlike the general subway system that uses a positive contact network for power supply and a negative contact network for return flow, the monorail vehicle's DC traction system relies on a dedicated negative contact network for return flow. Therefore, the detection and protection of grounding faults in the monorail vehicle system has become a key issue that needs to be urgently addressed and improved.

[0003] Currently, there are two established methods for detecting ground faults: the 64D ground fault protection device on the power supply side and the GR ground fault protection device on the vehicle side. Based on current application, both methods effectively protect the line and onboard equipment. Both ground fault protection devices rely on voltage differences between different circuits. Therefore, if a ground fault occurs within a train station, it can cause widespread tripping of other vehicles and power supply equipment within the station, triggering a ground fault alarm. If a ground fault occurs between stations, the ground fault protection devices of other units on the train will also activate, failing to pinpoint the actual faulty equipment. Therefore, while currently established ground fault protection devices can provide rapid protection when a monorail vehicle experiences a ground fault, they cannot quickly and effectively locate the fault point, necessitating a complete vehicle power outage and reliance on other trains for rescue, severely impacting operations. Summary of the Invention

[0004] An object of the present invention is to provide a system that can accurately locate a ground fault in a monorail vehicle.

[0005] To achieve the above object, the technical solution adopted by the present invention is:

[0006] A ground fault hierarchical detection and positioning system for a monorail vehicle includes a fault detection unit provided in each train unit, the fault detection unit including:

[0007] Voltage sensor, installed between the negative bus and the vehicle body, used to detect the voltage between the negative bus and the vehicle body ;

[0008] Data acquisition unit: collects the voltage value detected by the voltage sensor,

[0009] Fault analysis unit: Analyzes and locates the monorail vehicle grounding fault based on the voltage value collected by the data acquisition unit:

[0010] like , the fault occurs between the train's AC380V system and the train body, or between the AC220V system and the train body;

[0011] like , the fault occurs between the DC110V system and the vehicle body;

[0012] in, is the first judgment threshold set, is the second determination threshold set, is the set third determination threshold.

[0013] In some embodiments of the present invention, the fault detection unit further includes:

[0014] Positive bus current sensor group, including one or a combination of the following sensors,

[0015] Positive current sensor of auxiliary power box: connected in parallel with the connecting line between the positive busbar and the auxiliary power box;

[0016] Traction inverter box positive current sensor: connected in parallel with the connection line between the positive busbar and the traction inverter box;

[0017] Negative bus current sensor group, including one or a combination of the following sensors,

[0018] Auxiliary power box negative current sensor: connected in parallel with the connecting line between the negative bus and the auxiliary power box;

[0019] Traction inverter box negative current sensor: connected in parallel with the connection line between the negative busbar and the traction inverter box;

[0020] The data acquisition unit further acquires currents of the positive bus current sensor group and the negative bus current sensor group;

[0021] The fault analysis unit further analyzes and locates the grounding fault of the monorail vehicle based on the current value and voltage value collected by the data collection unit:

[0022] like , and the current difference detected by the auxiliary power box positive current sensor and the auxiliary power box negative current sensor is greater than or equal to the set current threshold, it is determined that the short circuit fault occurs in the auxiliary power box;

[0023] like , and the current difference detected by the positive current sensor of the traction inverter box and the negative current sensor of the traction inverter box is greater than or equal to the set current threshold, it is determined that the short circuit fault occurs in the traction inverter box.

[0024] In some embodiments of the present invention, each traction inverter box corresponds to a traction inverter box positive current sensor and a traction inverter box negative current sensor.

[0025] In some embodiments of the present invention,

[0026] The connection line between the positive busbar and the auxiliary power supply box, as well as the connection line between the positive busbar and the traction inverter box, are combined into the positive busbar main line, which is connected to the positive busbar; the connection line between the negative busbar and the auxiliary power supply box, as well as the connection line between the negative busbar and the traction inverter box, are combined into the negative busbar main line, which is connected to the negative busbar;

[0027] The fault detection unit includes:

[0028] Positive pantograph current sensor: connected in parallel with the positive busbar main line;

[0029] Negative pantograph current sensor: connected in parallel with the negative busbar main line;

[0030] The data acquisition unit further acquires currents of the positive pantograph current sensor and the negative pantograph current sensor;

[0031] The fault analysis unit further analyzes and locates the grounding fault of the monorail vehicle based on the current value and voltage value collected by the data collection unit:

[0032] If the short-circuit fault does not occur in the traction inverter box or the auxiliary power supply box, and the current difference between the positive pantograph current sensor and the negative pantograph current sensor is greater than or equal to the set current threshold, it is determined that the short-circuit fault occurs between the pantograph and the auxiliary power supply box, or between the pantograph and the traction inverter box.

[0033] In some embodiments of the present invention, the fault analysis unit is further configured to:

[0034] Fault classification detection and positioning are carried out when the train is running between stations or when it stops at a station.

[0035] In some embodiments of the present invention, when the train is running between stations, the fault analysis unit is further configured to:

[0036] If there is a short circuit fault, and the fault is eliminated between the AC380V system and the vehicle body, between the AC220V system and the vehicle body, between the DC110V system and the vehicle body, the auxiliary power box, the traction inverter box, between the pantograph and the auxiliary power box, and between the pantograph and the traction inverter box, then it is determined that the short circuit fault occurs between the positive pantograph and the vehicle body.

[0037] In some embodiments of the present invention, if the train stops in a station, the fault analysis unit is further configured to:

[0038] If a short circuit fault exists and the fault occurs between the AC380V system and the vehicle body, or between the AC220V system and the vehicle body, between the DC110V system and the vehicle body, the auxiliary power box, the traction inverter box, between the pantograph and the auxiliary power box, or between the pantograph and the traction inverter box, then:

[0039] Control all pantographs to lower and close the contact network:

[0040] If there is a fault: it is determined that the ground fault occurs in the overhead line or substation;

[0041] If the fault is eliminated: control all pantographs to raise and determine that the short circuit fault occurs between the positive pantograph and the vehicle body.

[0042] In some embodiments of the present invention, after the short circuit fault is located, the faulty device is disconnected.

[0043] In some embodiments of the present invention, is 80V, is 150V, It is 600V.

[0044] In some embodiments of the present invention, the current threshold is 50A.

[0045] The ground fault hierarchical detection and positioning system provided by the present invention has the following beneficial effects:

[0046] To address the difficulty in quickly locating the fault point after a ground fault occurs on a monorail train, a hierarchical detection and location system for monorail ground faults has been proposed. This system adds some onboard voltage and current sensors to the train, and by comparing and analyzing the collected voltage and current values, it automatically locates the system or equipment where the ground fault occurred. The system offers the following technical benefits:

[0047] 1. The hierarchical detection and positioning system can detect ground faults occurring in monorail vehicles within or between stations, and cut off the faulty equipment, ensuring the normal operation of other equipment and the personal safety of passengers.

[0048] 2. The hierarchical detection and positioning system can automatically and quickly lock the fault location after a ground fault occurs on a monorail train, and isolate the faulty equipment separately, ensuring that the train has the ability to self-rescue and return to the depot, thereby improving the train's operating efficiency.

[0049] 3. The hierarchical detection and positioning system can help maintenance personnel quickly and accurately locate the grounding position and carry out maintenance on it, thereby improving the efficiency of train maintenance. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0051] Figure 1 This is a schematic diagram of the structure of the ground fault hierarchical detection and positioning system provided by the present invention;

[0052] Figure 2 A schematic diagram of the ground fault location structure of the ground fault hierarchical detection and location system provided by the present invention;

[0053] Figure 3 A flow chart of inter-station detection of ground faults in the ground fault hierarchical detection and positioning system provided by the present invention;

[0054] Figure 4 This is a flow chart of ground fault in-station detection of the ground fault hierarchical detection and positioning system provided by the present invention. DETAILED DESCRIPTION

[0055] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0056] The present invention provides a ground fault hierarchical detection and positioning system applicable to a monorail vehicle. The system can accurately locate the fault location when a ground fault occurs in the monorail vehicle.

[0057] refer to Figure 2 According to the different locations of ground faults on monorail vehicles, the locations of ground faults on the entire vehicle are divided into 6 levels, which can basically cover all possible occurrences of ground faults on monorail vehicles. The specific classification is as follows:

[0058] (1) Grounding position 1: The positive busbar or pantograph is short-circuited with the vehicle body.

[0059] (2) Grounding position 2: After the positive current sensor, before the VVVF box (traction inverter box), short-circuited with the vehicle body.

[0060] (3) Grounding position 3: A short circuit occurs between the inside of the VVVF box (traction inverter box) or the inside of the auxiliary power box and the vehicle body.

[0061] (4) Grounding position 4: The AC380V and AC220V systems are short-circuited with the vehicle body.

[0062] (5) Grounding position 5: The DC110V system is short-circuited with the vehicle body.

[0063] (6) Grounding position 6: The positive contact network is short-circuited with the ground.

[0064] Structural reference of ground fault hierarchical detection and positioning system Figure 1, including a fault detection unit installed in each train unit, which can perform independent fault detection on each car. The configuration of the fault detection unit in each car is basically the same, with slight differences depending on the configuration of the specific electrical equipment in the car.

[0065] The structure of the fault detection unit includes:

[0066] Voltage sensor TV, set between the negative bus and the vehicle body, is used to detect the voltage between the negative bus and the vehicle body ;

[0067] Data acquisition unit: collects the voltage value detected by the voltage sensor;

[0068] Fault analysis unit: Analyzes and locates the monorail vehicle grounding fault based on the voltage value collected by the data acquisition unit:

[0069] like , the fault occurs between the train's AC380V system and the car body, or between the AC220V system and the car body; corresponding to the grounding position 4 mentioned above.

[0070] like , the fault occurs between the DC110V system and the vehicle body; this corresponds to the grounding position 5 mentioned above.

[0071] in, is the first judgment threshold set, is the second determination threshold set, The third determination threshold value may be set according to the configuration of the system. In some embodiments of the present invention, is 80V, is 150V, It is 600V.

[0072] Right now:

[0073] like , the fault occurs between the train's AC380V system and the car body, or between the AC220V system and the car body; corresponding to the grounding position 4 mentioned above.

[0074] like , the fault occurs between the DC110V system and the vehicle body; this corresponds to the grounding position 5 mentioned above.

[0075] Through the above steps, when a ground fault occurs on a train, the voltage level at the fault location is accurately determined based on the voltage value collected by the voltage sensor (TV1) between the negative busbar and the car body: DC1500V system, AC380V / AC220V system, and DC110V system. The fault location can then be quickly narrowed down based on the voltage level. If the fault is located in the DC1500V system, the following steps are used to further narrow the fault.

[0076] In some embodiments of the present invention, the fault detection unit further includes:

[0077] Positive bus current sensor group, including one or a combination of the following sensors:

[0078] Positive current sensor of auxiliary power box: connected in parallel with the connecting line between the positive busbar and the auxiliary power box;

[0079] Traction inverter box positive current sensor: connected in parallel with the connection line between the positive busbar and the traction inverter box;

[0080] Negative bus current sensor group, including one or a combination of the following sensors:

[0081] Negative current sensor of the auxiliary power box: connected in parallel with the connecting line between the negative bus and the auxiliary power box;

[0082] Traction inverter box negative current sensor: connected in parallel with the connection line between the negative busbar and the traction inverter box;

[0083] The data acquisition unit further acquires the current of the positive bus current sensor group and the negative bus current sensor group;

[0084] The fault analysis unit further analyzes and locates the monorail vehicle grounding fault based on the current and voltage values ​​collected by the data acquisition unit:

[0085] like ,Right now , and the current difference detected by the auxiliary power box positive current sensor and the auxiliary power box negative current sensor is greater than or equal to the set current threshold, it is determined that the short circuit fault occurs in the auxiliary power box;

[0086] like ,Right now , and the current difference detected by the positive current sensor of the traction inverter box and the negative current sensor of the traction inverter box is greater than or equal to the set current threshold, it is determined that the short circuit fault occurs in the traction inverter box.

[0087] To achieve more accurate fault location, in some embodiments of the present invention, each traction inverter box corresponds to a traction inverter box positive current sensor and a traction inverter box negative current sensor.

[0088] In some embodiments of the present invention, the current threshold is 50A.

[0089] refer to Figure 1 Taking the specific configuration of a train car as an example, the car is equipped with an auxiliary system (auxiliary power supply box) and three traction inverter boxes. The auxiliary system is connected between the positive and negative busbars. The auxiliary power supply box's positive current sensor (LH1) is connected to the line connecting the auxiliary system to the positive busbar, and the auxiliary power supply box's negative current sensor (LH2) is connected to the line connecting the auxiliary power supply box to the negative busbar. The traction inverter box is also connected between the positive and negative busbars. The traction inverter box's positive current sensor is connected to the line connecting the traction inverter box to the positive busbar, and the traction inverter box's negative current sensor is connected to the line connecting the traction inverter box to the negative busbar. In this embodiment, each car contains three traction inverter boxes. The first traction inverter box's positive current sensor (LH3) is installed on the line connecting the traction inverter box VVVF1 to the positive busbar, and the first traction inverter box's negative current sensor (LH4) is installed on the line connecting the traction inverter box VVVF1 to the negative busbar. A second traction inverter box positive current sensor (LH5) is installed on the line connecting traction inverter box VVVF2 and the positive busbar, and a second traction inverter box negative current sensor (LH6) is installed on the line connecting traction inverter box VVVF1 and the negative busbar. A third traction inverter box positive current sensor (LH7) is installed on the line connecting traction inverter box VVVF1 and the positive busbar, and a third traction inverter box negative current sensor (LH8) is installed on the line connecting traction inverter box VVVF1 and the negative busbar. If there are other traction inverter boxes in the car, the number of traction inverter box positive current sensors and traction inverter box negative current sensors can be increased accordingly.

[0090] If the current difference between LH3 and LH4 is greater than or equal to 50A, the fault is determined to have occurred in the traction inverter box VVVF1;

[0091] If the current difference between LH5 and LH6 is greater than or equal to 50A, the fault is determined to be in the traction inverter box VVVF2;

[0092] If the current difference between LH7 and LH8 is greater than or equal to 50A, it is determined that the fault occurs in the traction inverter box VVVF3.

[0093] If the current difference between LH1 and LH2 is greater than or equal to 50A, it is determined that the fault occurs in the auxiliary power box.

[0094] The above fault corresponds to the grounding position 3 mentioned above.

[0095] If the fault occurs in the high-voltage bus system (DC1500V), the above steps can accurately locate the equipment box where the ground fault occurs based on the current difference collected by the positive and negative bus current sensors inside each device in the traction system, and the faulty device can be removed. After that, the train can operate normally. If no internal ground fault is detected in all devices, the following detection structure is available, and the following detection steps are continued.

[0096] The connection lines between the positive busbar and the auxiliary power box, as well as the connection lines between the positive busbar and the traction inverter box, are combined into the positive busbar main line, which is connected to the positive busbar; the connection lines between the negative busbar and the auxiliary power box, as well as the connection lines between the negative busbar and the traction inverter box, are combined into the negative busbar main line, which is connected to the negative busbar. The voltage sensor is set in parallel between the vehicle body and the negative busbar;

[0097] The fault detection unit includes:

[0098] Positive pantograph current sensor (LHA): connected in parallel with the positive busbar main line;

[0099] Negative pantograph current sensor (LHB): connected in parallel with the negative busbar main line;

[0100] The data acquisition unit further acquires currents of the positive pantograph current sensor and the negative pantograph current sensor;

[0101] The fault analysis unit further analyzes and locates the monorail vehicle grounding fault based on the current and voltage values ​​collected by the data acquisition unit:

[0102] If the short-circuit fault does not occur in the traction inverter box or the auxiliary power supply box, and the current difference between the positive pantograph current sensor and the negative pantograph current sensor is greater than or equal to the set current threshold, it is determined that the short-circuit fault occurs between the pantograph and the auxiliary power supply box, or between the pantograph and the traction inverter box.

[0103] For the configuration of auxiliary power box and multi-traction inverter box, refer to Figure 1 As can be seen, the output of the positive pantograph current sensor (LHA) has multiple branches, each of which is connected to the positive current sensor of the auxiliary power box or a positive current sensor of the traction inverter box. The negative pantograph current sensor (LHB) has multiple inputs, and the positive current sensor of the auxiliary power box and each positive current sensor of the traction inverter box converges into the negative pantograph current sensor (LHB).

[0104] The data acquisition unit further acquires currents of the positive pantograph current sensor and the negative pantograph current sensor;

[0105] The fault analysis unit further analyzes and locates the monorail vehicle grounding fault based on the current and voltage values ​​collected by the data acquisition unit:

[0106] If the short-circuit fault does not occur in the traction inverter box or the auxiliary power supply box, and the current difference between the positive pantograph current sensor and the negative pantograph current sensor is greater than or equal to the set current threshold, it is determined that the short-circuit fault occurs between the pantograph and the auxiliary power supply box, or between the pantograph and the traction inverter box.

[0107] That is, if the current difference between LHA and LHB is greater than 50A, the fault occurs between the pantograph and the auxiliary power box, or between the pantograph and the traction inverter box.

[0108] The above fault corresponds to the grounding position 2 mentioned above.

[0109] According to the current difference collected by the positive pantograph and the negative pantograph current sensors, if the difference is too large, it is determined that a grounding fault has occurred in the cable from the pantograph to the outside of the equipment box. The pantograph of the faulty unit is lowered, and other units that have not failed are used to run to the nearest station. After evacuating the passengers, return to the vehicle base; if the positive and negative bus current difference is normal, the following detection structure is present, and the following detection steps are continued.

[0110] The above fault classification detection and positioning method is carried out when the train is running between stations or when it is stopping at a station.

[0111] In addition to the above methods, in some embodiments of the present invention, if the inter-station operation is in progress, the following fault location detection is further performed.

[0112] The fault analysis unit is further configured to:

[0113] If a short circuit occurs between the AC380V system and the car body, the AC220V system and the car body, the DC110V system and the car body, the auxiliary power supply box, the traction inverter box, the pantograph to the auxiliary power supply box, or the pantograph to the traction inverter box, the short circuit is determined to be between the positive pantograph and the car body. Lower the pantograph of the faulty unit, and run the train to the nearest station using the remaining units. After evacuating passengers, return to the train depot.

[0114] The above fault corresponds to the grounding position 1 mentioned above.

[0115] In addition to the above method, in some embodiments of the present invention, if the train stops in a station, the following fault location detection is further performed.

[0116] The fault analysis unit is further configured to:

[0117] If a short circuit fault exists and the fault occurs between the AC380V system and the vehicle body, or between the AC220V system and the vehicle body, between the DC110V system and the vehicle body, the auxiliary power box, the traction inverter box, between the pantograph and the auxiliary power box, or between the pantograph and the traction inverter box, then:

[0118] Control all pantographs to lower and close the contact network:

[0119] If there is a fault: it is determined that the ground fault occurs in the overhead line or substation;

[0120] If the fault is eliminated: control all pantographs to raise and determine that the short circuit fault occurs between the positive pantograph and the vehicle body.

[0121] In some embodiments of the present invention, after the short circuit fault is located, the faulty device is disconnected.

[0122] Specifically, when a train is docked at a station, the train body is connected to the ground via a grounding device to protect passengers from electric shock. Therefore, the train body and the ground are at the same potential. If a ground fault occurs on a train at a station, not only will the onboard ground detection device activate, but the 64D ground fault protection device in the substation will also activate.

[0123] According to the above characteristics, when a grounding fault occurs on a train in a station, the specific steps for locating the grounding point are as follows. The difference between the confirmation of the grounding point position on the vehicle side and the fault locating between train stations is that when a grounding fault occurs in the positive pantograph circuit and above of the train, it is necessary to combine the contact network and substation for investigation. All trains in the station need to lower their pantographs and then close the contact network. If the grounding fault still exists, it can be determined that the contact network line or substation is grounded. If the fault is eliminated, the pantographs of the trains in the station need to be raised one by one to lock the faulty vehicle, lower the pantograph of the faulty unit, and after evacuating the passengers, the train uses the remaining units to return to the vehicle base.

[0124] The fault hierarchical location detection system provided by the present invention, after a ground fault occurs on a monorail vehicle, hierarchically divides the possible grounding locations on the vehicle and power supply sides. Using the voltage and current values ​​collected by onboard voltage and current sensors, it quickly locates the vehicle ground fault system and the specific faulty device. The faulty device or unit is then removed to ensure the train can self-rescue and return to the depot. This method improves the accuracy of fault location and enhances the safety and reliability of train operations.

[0125] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A ground fault hierarchical detection and positioning system suitable for monorail vehicles, characterized in that: The system comprises a fault detection unit provided in each train unit, wherein the fault detection unit comprises: Voltage sensor: set between the negative bus and the vehicle body, used to detect the voltage between the negative bus and the vehicle body ; Data acquisition unit: collects the voltage value detected by the voltage sensor, Fault analysis unit: Analyzes and locates the monorail vehicle grounding fault based on the voltage value collected by the data acquisition unit: like , the fault occurs between the train's AC380V system and the train body, or between the AC220V system and the train body; like , the fault occurs between the DC110V system and the vehicle body; in, is the first judgment threshold set, is the second determination threshold set, is the set third determination threshold; The fault detection unit further comprises: Positive bus current sensor group, including one or a combination of the following sensors, Positive current sensor of auxiliary power box: connected in parallel with the connecting line between the positive busbar and the auxiliary power box; Traction inverter box positive current sensor: connected in parallel with the connection line between the positive busbar and the traction inverter box; Negative bus current sensor group, including one or a combination of the following sensors, Auxiliary power box negative current sensor: connected in parallel with the connecting line between the negative bus and the auxiliary power box; Traction inverter box negative current sensor: connected in parallel with the connection line between the negative busbar and the traction inverter box; The data acquisition unit further acquires currents of the positive bus current sensor group and the negative bus current sensor group; The fault analysis unit further analyzes and locates the grounding fault of the monorail vehicle based on the current value and voltage value collected by the data collection unit: like , and the current difference detected by the auxiliary power box positive current sensor and the auxiliary power box negative current sensor is greater than or equal to the set current threshold, it is determined that the short circuit fault occurs in the auxiliary power box; like , and the current difference detected by the positive current sensor of the traction inverter box and the negative current sensor of the traction inverter box is greater than or equal to the set current threshold, it is determined that the short circuit fault occurs in the traction inverter box.

2. The ground fault hierarchical detection and positioning system for monorail vehicles according to claim 1, characterized in that: Each traction inverter box corresponds to a traction inverter box positive current sensor and a traction inverter box negative current sensor.

3. The ground fault hierarchical detection and positioning system for monorail vehicles according to claim 1, characterized in that: The connection line between the positive busbar and the auxiliary power supply box, as well as the connection line between the positive busbar and the traction inverter box, are combined into the positive busbar main line, which is connected to the positive busbar; the connection line between the negative busbar and the auxiliary power supply box, as well as the connection line between the negative busbar and the traction inverter box, are combined into the negative busbar main line, which is connected to the negative busbar; The fault detection unit includes: Positive pantograph current sensor: connected in parallel with the positive busbar main line; Negative pantograph current sensor: connected in parallel with the negative busbar main line; The data acquisition unit further acquires currents of the positive pantograph current sensor and the negative pantograph current sensor; The fault analysis unit further analyzes and locates the grounding fault of the monorail vehicle based on the current value and voltage value collected by the data collection unit: If the short-circuit fault does not occur in the traction inverter box or the auxiliary power supply box, and the current difference between the positive pantograph current sensor and the negative pantograph current sensor is greater than or equal to the set current threshold, it is determined that the short-circuit fault occurs between the pantograph and the auxiliary power supply box, or between the pantograph and the traction inverter box.

4. The ground fault hierarchical detection and positioning system for monorail vehicles according to any one of claims 1 to 3, characterized in that: The fault analysis unit is further configured to: Fault classification detection and positioning are carried out when the train is running between stations or when it stops at a station.

5. The ground fault hierarchical detection and positioning system for monorail vehicles according to claim 4, characterized in that: When the train is running between stations, the fault analysis unit is further configured to: If there is a short circuit fault, and the fault is eliminated between the AC380V system and the vehicle body, between the AC220V system and the vehicle body, between the DC110V system and the vehicle body, the auxiliary power box, the traction inverter box, between the pantograph and the auxiliary power box, and between the pantograph and the traction inverter box, then it is determined that the short circuit fault occurs between the positive pantograph and the vehicle body.

6. The ground fault hierarchical detection and positioning system for monorail vehicles according to claim 4, characterized in that: If the train stops at the station, the fault analysis unit is further configured to: If a short circuit fault exists and the fault occurs between the AC380V system and the vehicle body, between the AC220V system and the vehicle body, between the DC110V system and the vehicle body, the auxiliary power box, the traction inverter box, between the pantograph and the auxiliary power box, and between the pantograph and the traction inverter box, then: Control all pantographs to lower and close the contact network: If there is a fault: it is determined that the ground fault occurs in the overhead line or substation; If the fault is eliminated: control all pantographs to raise and determine that the short circuit fault occurs between the positive pantograph and the vehicle body.

7. The ground fault hierarchical detection and positioning system for monorail vehicles according to claim 1, characterized in that: After locating the short circuit fault, disconnect the faulty device.

8. The ground fault hierarchical detection and positioning system for monorail vehicles according to claim 1, characterized in that: is 80V, is 150V, It is 600V.

9. The ground fault hierarchical detection and positioning system for monorail vehicles according to claim 1 or 3, characterized in that: The current threshold is 50A.

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