A grounding conduction device and DC traction power supply system

Abstract

The present application discloses a grounding conduction device, which includes a plurality of first branches and a controller; the plurality of first branches are connected in parallel; wherein the controller is connected to each of the plurality of first branches, and is used to control each of the plurality of first branches to be in an on state or a off state. The present application also discloses a DC traction power supply system, which includes a traction rectifier unit, a contact network, a return rail, a running rail, a grounding network, and the grounding conduction device; the positive pole of the traction rectifier unit, the contact network, the train, the return rail, and the negative pole of the traction rectifier unit are sequentially connected to form an electrical circuit to provide electrical energy for the train; the grounding conduction device is arranged between the running rail and the negative pole of the traction rectifier unit.

Description

Technical Field

[0001] The embodiments of the present application relate to the field of urban rail transit power supply technology, and in particular to a grounding conduction device and a DC traction power supply system. Background Art

[0002] The conventional design of the urban rail DC traction power supply system is to use the contact network or contact rail to transfer current to the pantograph or collector shoe of the train. The train contacts the rail through the wheelset, and the rail leads the current to the traction substation through the cable to form a complete electrical circuit. Due to the poor insulation performance to the ground, the rail inevitably leaks current to the roadbed and stations, tunnel structures, viaducts, etc. This part of the current can be widely distributed due to the different conductive properties of the earth's soil and the location of underground metal pipelines. It is called "stray current" or "stray current". The existence of stray current will corrode the main structure of rail transit and the urban pipelines or structural steel bars along the line, affecting the safe operation of rail transit and the safety and life of public facilities along the rail transit. In the prior art, an insulated return rail is laid beside the line, and the return rail is connected to the negative pole of the DC traction power supply inside the train through the collector shoe. The return rail is connected to the negative pole of the traction rectifier unit on the traction substation side to form an electrical circuit consisting of the positive pole of the traction rectifier unit-contact network-train-return rail-negative pole of the traction rectifier unit. However, the insulation installation of the return rail will also cause insulation leakage or short circuit between the DC positive pole (i.e., the contact network) and the ground. The DC protection system that relies on the current flow to operate cannot monitor the fault, which brings certain hidden dangers to the safe operation of the system. Summary of the invention

[0003] In order to solve the above technical problems, the embodiments of the present application provide a grounding conduction device and a DC traction power supply system.

[0004] The embodiment of the present application provides a grounding conduction device, the device comprising a plurality of first branches and a controller; the plurality of first branches are connected in parallel; wherein,

[0005] The controller is connected to each of the plurality of first branches, and is used to control each of the plurality of first branches to be in an on state or an off state.

[0006] In an optional embodiment of the present application, each of the plurality of first branches has a first end and a second end;

[0007] Each of the plurality of first branches comprises a diode, a first switch and a first shunt; wherein the diode, the first switch and the first shunt in each of the first branches are connected in series in any order;

[0008] The first end of each of the plurality of first branches is connected in parallel to form an input end of the ground connection device;

[0009] The controller is connected to the first shunt in each first branch, and is used to detect the current of the first shunt in each first branch;

[0010] The controller is also connected to the first switch in each of the first branches, and is used to control the state of the first switch in each of the first branches according to the detected current of the first shunt in each of the first branches.

[0011] In an optional implementation manner of the present application, the diode, the first switch and the first shunt are connected in series in any order, including:

[0012] The diode, the first switch and the first shunt are connected in series in sequence; or,

[0013] The diode, the first shunt and the first switch are connected in series in sequence; or,

[0014] The first switch, the diode and the first shunt are connected in series in sequence; or,

[0015] The first switch, the first shunt and the diode are connected in series in sequence; or,

[0016] The first shunt, the diode and the first switch are connected in series in sequence; or,

[0017] The first shunt, the first switch and the diode are connected in series in sequence.

[0018] In an optional implementation manner of the present application, the series connection mode of the internal components of different first branches in the plurality of first branches is the same; or,

[0019] Different first branch internal components in the plurality of first branches are connected in series in different ways;

[0020] Wherein, the internal components include the diode, the first switch and the first shunt.

[0021] In an optional embodiment of the present application, the device further comprises a second branch having a third end and a fourth end;

[0022] The second branch includes a second shunt and a second switch, wherein the second shunt and the second switch are connected in series in any manner;

[0023] The third end of the second branch is connected to the second end of each of the plurality of first branches; the fourth end of the second branch constitutes the output end of the ground connection device;

[0024] The controller is connected to the second shunt and is used to detect the current in the second shunt;

[0025] The controller is connected to the second switch and is used to control the state of the second switch.

[0026] In an optional implementation manner of the present application, the second shunt and the second switch are connected in series in any manner, including:

[0027] The second switch and the second shunt are connected in series in sequence; or,

[0028] The second shunt and the second switch are connected in series in sequence.

[0029] In an optional implementation manner of the present application, the input end of the grounding conductive device is grounded, and the output end of the grounding conductive device is connected to a negative electrode.

[0030] The present application also provides a DC traction power supply system, which includes a traction rectifier unit, a contact network, a return rail, a running rail and a grounding network, and the grounding conduction device described in the above embodiment; wherein,

[0031] The positive electrode of the traction rectifier unit, the overhead line, the train, the return rail and the negative electrode of the traction rectifier unit are sequentially connected to form an electrical circuit to provide electrical energy for the train;

[0032] The grounding conduction device is arranged between the running rail and the negative pole of the traction rectifier unit.

[0033] In an optional embodiment of the present application, a plurality of grounding conduction devices are arranged between the running rail and the negative pole of the traction rectifier unit; wherein the input end of the grounding conduction device is connected to the running rail, and the output end of the grounding conduction device is connected to the negative pole of the traction rectifier unit.

[0034] In an optional implementation manner of the present application, the current of the second shunt in two or more grounding conduction devices among the multiple grounding conduction devices is used to determine the interval in which the contact network or the return rail generates leakage current to the ground.

[0035] In an optional implementation manner of the present application, the DC traction power supply system further includes: a feeder protection circuit; wherein,

[0036] The feeder protection circuit is arranged between the positive pole of the traction rectifier unit and the contact network, and is used to cut off the current between the contact network and the ground when the contact network is short-circuited to the ground.

[0037] In an optional embodiment of the present application, the system includes multiple sections of running rails, which are connected by cables to form a passage; wherein the passage formed by the multiple sections of running rails is connected to the ground or each section of the multiple sections of running rails is connected to the ground.

[0038] In an optional implementation of the present application, the running rail is installed in a non-insulated manner.

[0039] In an optional embodiment of the present application, the running rail is connected to the structural steel bars and shielding doors of the platform at the station with the same potential; or, the running rail is connected to the structural steel bars and safety doors of the platform at the station with the same potential.

[0040] In the technical solution of the embodiment of the present application, the grounding conduction device includes a plurality of first branches and a controller; the plurality of first branches are connected in parallel; wherein the controller is connected to each of the plurality of first branches, and is used to control each of the plurality of first branches to be in an on state or a disconnected state. In this way, the control of the controller can ensure that the current in the grounding conduction device only flows from the input end to the output end. The DC traction power supply system provided in the embodiment of the present application includes a traction rectifier unit, a contact network, a return rail, a running rail, a grounding network and a grounding conduction device; wherein the positive pole of the traction rectifier unit, the contact network, the train, the return rail and the negative pole of the traction rectifier unit are sequentially connected to form an electrical circuit to provide electrical energy for the train; the grounding conduction device is arranged between the running rail and the negative pole of the traction rectifier unit. In this way, the current in the return rail can be prevented from flowing to the ground to generate stray current. At the same time, without destroying the stray current protection performance of the DC traction power supply system, when the contact network is short-circuited to the ground and current leakage occurs, the feeder protection circuit is used to cut off the current between the contact network and the ground, and only the faulty section of the system is cut off, avoiding large-scale tripping caused by partial faults in the system, thereby improving the safety and reliability of system operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 A schematic diagram of a DC leakage protection device provided between a return rail and a ground according to an embodiment of the present application;

[0042] Figure 2 A schematic diagram of a grounding conduction device provided in an embodiment of the present application;

[0043] Figure 3 A schematic diagram of the composition of the first branch provided in an embodiment of the present application;

[0044] Figure 4 A schematic diagram of the composition of the second branch provided in an embodiment of the present application;

[0045] Figure 5A schematic diagram of a specific implementation of a grounding conduction device provided in an embodiment of the present application;

[0046] Figure 6 Schematic diagram of a DC traction power supply system provided in an embodiment of the present application. DETAILED DESCRIPTION

[0047] In order to enable a more detailed understanding of the features and technical contents of the embodiments of the present application, the implementation of the embodiments of the present application is described in detail below in conjunction with the accompanying drawings. The attached drawings are for reference only and are not used to limit the embodiments of the present application.

[0048] In one embodiment, a dedicated return rail is used in some track lines to prevent the generation of stray current. The train on the track does not use the running rail for return current, but an insulated return rail is laid beside the line. The return rail is connected to the negative pole of the DC traction power supply in the car through the power receiving shoe, wherein the negative pole inside the train is insulated from the car body, and the return rail is connected to the negative pole of the traction rectifier unit on the traction substation side, forming an electrical circuit consisting of the positive pole of the traction rectifier unit-contaminant network-train-return rail-negative pole of the traction rectifier unit. Because the return rail is installed with an insulator or an integral insulating bracket, wherein the volume resistivity of the return rail ρ≥10 13 Ω. Under the specified working voltage, the leakage current of the return rail to the ground is close to zero, and the return rail can be considered to be a truly insulated installation. However, the insulated installation of the return rail will also lead to insulation leakage or short circuit to the ground of the positive pole of the power supply system (such as the positive pole of the traction rectifier unit or the contact network). Since the return rail cannot form a through electrical circuit, the feeder protection circuit that relies on the current for protection cannot monitor the fault, which brings certain safety hazards to the operation of the DC traction power supply system.

[0049] In another embodiment, using Figure 1 The leakage protection device shown in the figure. Figure 1As shown, in a DC traction power supply system with a dedicated return rail, a DC leakage protection device is provided between the return rail and the ground, and the device is composed of a diode and a voltage monitoring unit; wherein the diode is used to prevent the current from flowing from the return rail to the ground; the voltage monitoring unit is used to monitor the voltage between the return rail and the ground in real time, and when the voltage is higher than the set value (generally set between 170V-200V), the voltage monitoring unit sends a trip signal, triggering the DC feeder protection circuit of the traction substation to disconnect, cut off the short-circuit current between the positive pole of the traction rectifier unit and the ground, and prevent the accident from further expanding and damaging the power supply equipment. However, when this embodiment is adopted, since the negative poles of the entire DC traction power supply system are connected together and the ground is also connected, when one point in the DC traction power supply system is grounded or seriously leaks, the DC feeder protection circuit of the traction substation is disconnected only based on the potential difference between the negative pole and the ground, which is easy to cause a large-scale tripping of the DC traction power supply system.

[0050] Based on the analysis of the above two implementation methods, various embodiments of the present application are proposed.

[0051] Figure 2 A schematic diagram of a ground connection device 100 provided in an embodiment of the present application is shown in FIG. Figure 2 As shown, the device includes a plurality of first branches 101 and a controller 102; the plurality of first branches 101 are connected in parallel; wherein,

[0052] The controller 102 is connected to each of the plurality of first branches 101 , and is used to control each of the plurality of first branches 101 to be in an on state or an off state.

[0053] Specifically, the controller is connected to each of the multiple first branches. In one embodiment, a voltage threshold at both ends of each of the multiple first branches can be set, and the controller monitors the voltage at both ends of each of the multiple first branches. When the voltage of one or more of the first branches exceeds the set voltage threshold, the controller cuts off the one or more first branches whose voltages at both ends exceed the set voltage threshold. In another embodiment, a threshold of the current flowing through each of the multiple first branches can be set, and the controller monitors the current flowing through the multiple first branches. When the current in one or more of the first branches exceeds the set current threshold, the controller cuts off the one or more first branches whose current exceeds the set current threshold.

[0054] In an optional implementation manner of the present application, each of the plurality of first branches 101 has a first end and a second end; Figure 3 A schematic diagram of the composition of the first branch 101 provided in the embodiment of the present application is shown as follows: Figure 3As shown:

[0055] Each of the plurality of first branches 101 comprises a diode 1011, a first switch 1012 and a first shunt 1013; wherein the diode 1011, the first switch 1012 and the first shunt 1013 in each of the first branches 101 are connected in series in any order;

[0056] The first end of each first branch 101 of the plurality of first branches 101 is connected in parallel to form an input end of the ground connection device 100;

[0057] The controller 102 is connected to the first shunt 1013 in each first branch 101, and is used to detect the current of the first shunt 1013 in each first branch 101;

[0058] The controller 102 is also connected to the first switch 1012 in each first branch 101 , and is used to control the state of the first switch 1012 in each first branch 101 according to the detected current of the first shunt 1013 in each first branch 101 .

[0059] It should be noted that the diode 1011, the first switch 1012 and the first shunt 1013 are connected in series in any order, including:

[0060] The diode 1011, the first switch 1012 and the first shunt 1013 are connected in series in sequence; or,

[0061] The diode 1011, the first shunt 1013 and the first switch 1012 are connected in series in sequence; or,

[0062] The first switch 1012, the diode 1011 and the first shunt 1013 are connected in series in sequence; or,

[0063] The first switch 1012, the first shunt 1013 and the diode 1011 are connected in series in sequence; or,

[0064] The first shunt 1013, the diode 1011 and the first switch 1012 are connected in series in sequence; or,

[0065] The first shunt 1013 , the first switch 1012 , and the diode 1011 are sequentially connected in series.

[0066] In an optional implementation manner of the present application, the series connection mode of the internal components of different first branches 101 in the plurality of first branches 101 is the same; or,

[0067] Different first branches 101 in the plurality of first branches 101 have different serial connection modes of internal components;

[0068] The internal components include the diode 1011 , the first switch 1012 and the first shunt 1013 .

[0069] The grounding conduction device of the embodiment of the present application connects branches with diodes in series in parallel, so that when the diodes in one or more branches are in an abnormal state, the branch where the diodes in the abnormal state are located is disconnected, thereby preventing current from flowing from the output end to the input end of the grounding conduction device, and ensuring that the current flowing through the grounding conduction device can only flow from the input end to the output end.

[0070] Specifically, the controller is connected to the first shunt in each branch, and by detecting the current of the first shunt, it is determined whether the current of the first shunt in each branch exceeds the set current threshold value. If the current of the first shunt in a branch exceeds the set current threshold value, it indicates that the diode connected in series with the first shunt is in an abnormal state. At this time, in order to prevent the current from flowing from the output end to the input end in the grounding conduction device, the controller controls the first switch connected in series with the diode in the abnormal state to be disconnected.

[0071] In an embodiment of the present application, the current threshold of the first shunt in each branch can be set to indicate the current when the diode connected in series with the first shunt is in a breakdown state. The diode, the first switch and the first shunt in each of the multiple branches can be selected according to the actual application scenario of the grounding conduction device. Appropriate types and models can be selected. For example, a contactor can be selected as the first switch in each branch.

[0072] In an optional implementation manner of the present application, the device further includes a second branch 103, Figure 4 Schematic diagram of the composition of the second branch 103 provided in the embodiment of the present application, wherein the second branch 103 has a third end and a fourth end; Figure 4 Shown

[0073] The second branch 103 includes a second shunt 1032 and a second switch 1031, wherein the second shunt 1032 and the second switch 1031 are connected in series in any manner;

[0074] The third end of the second branch 103 is connected to the second end of each first branch 101 of the plurality of first branches 101; the fourth end of the second branch 103 constitutes the output end of the ground connection device 100;

[0075] The controller 102 is connected to the second shunt 1032 and is used to detect the current in the second shunt 1032;

[0076] The controller 102 is connected to the second switch 1031 and is used to control the state of the second switch 1031 .

[0077] It should be noted that the second shunt 1032 and the second switch 1031 are connected in series in any manner, including:

[0078] The second switch 1031 and the second shunt 1032 are connected in series in sequence; or,

[0079] The second shunt 1032 and the second switch 1031 are connected in series in sequence.

[0080] In the embodiment of the present application, the current of the second shunt is mainly used to determine the interval in which the positive pole of the traction rectifier unit generates current leakage to the ground; or to determine the interval in which the negative pole of the traction rectifier unit generates current leakage to the ground. In addition, in order to avoid damage to the equipment when operating the second switch under load, the current of the second shunt is also used to lock the operation of the second switch.

[0081] It should be noted that the types and models of the second shunt and the second switch can be selected according to the actual application scenarios of the grounding conduction device. For example, an isolating switch can be selected as the second switch.

[0082] In an optional implementation manner of the present application, the input end of the grounding and conducting device 100 is grounded, and the output end of the grounding and conducting device 100 is connected to a negative electrode.

[0083] Specifically, when using the grounding conduction device of the embodiment of the present application, the specific connection method of the grounding conduction device is set according to the actual application scenario. For example, when the grounding conduction device is applied to the power supply system of rail transportation, in order to ensure that the grounding conduction device can work normally, the input end of the grounding conduction device needs to be connected to the running rail, and the output end of the grounding conduction device needs to be connected to the negative pole of the traction rectifier unit.

[0084] Figure 5 A schematic diagram of a specific implementation of a grounding conduction device provided in an embodiment of the present application is shown in FIG. Figure 5 As shown, the grounding conduction device includes a plurality of first branches 101, a controller 102 and a second branch 103, wherein the plurality of first branches 101 are connected in parallel;

[0085] Each first branch 101 of the multiple first branches 101 includes a diode 1011, a first switch 1012 and a first shunt 1013 connected in series in sequence; wherein the positive electrode of the diode in each first branch 101 constitutes the first end of each first branch 101; and one end of the first shunt constitutes the second end of each first branch 101.

[0086] The anode of each diode 1011 in the plurality of first branches 101 is connected in parallel to form the input end of the ground connection device 100;

[0087] The controller 102 is connected to the first shunt 1013 in each first branch 101, and is used to detect the current of the first shunt 1013 in each first branch 101;

[0088] The controller 102 is also connected to the first switch 1012 in each first branch 101 , and is used to control the state of the first switch 1012 in each first branch 101 according to the detected current of the first shunt 1013 in each first branch 101 .

[0089] The second branch 103 includes a second shunt 1032 and a second switch 1031; wherein the first end of the second shunt 1032 constitutes the third end of the second branch 103, and the second end of the second switch constitutes the fourth end of the second branch 103;

[0090] The first end of the second splitter 1032 is connected to the first splitter 1013 in each branch;

[0091] The second end of the second shunt 1032 is connected to the first end of the second switch 1031;

[0092] The second end of the second switch 1031 constitutes the output end of the ground connection device 100;

[0093] The controller 102 is connected to the second shunt 1032 and is used to detect the current in the second shunt 1032;

[0094] The controller 102 is connected to the second switch 1031 and is used to control the state of the second switch 1031 .

[0095] The grounding conduction device provided in the embodiment of the present application can, on the one hand, determine the diode branch fault by detecting the current of the first shunt in each first branch through the controller, and automatically isolate the diode branch fault by controlling the first switch connected in series with the faulty diode through the controller; on the other hand, the current of the second shunt can also be detected by the controller, and the on or off state of the second switch can be controlled. For example, when the grounding conduction device is applied to the power supply system of rail transit, the second switch can be disconnected when the rail transit is under maintenance, thereby achieving the switching of the grounding conduction device between the maintenance state and the working state by controlling the on or off state of the second switch.

[0096] Figure 6 Schematic diagram of a DC traction power supply system provided in an embodiment of the present application. Figure 6As shown, the system includes a traction rectifier unit 600, a contact network 601, a return rail 602, a running rail 603 and a grounding network 604, and the grounding conduction device 100 described in the above embodiment; wherein,

[0097] The positive electrode of the traction rectifier unit 600, the overhead line 601, the train (not shown in the figure), the return rail 602 and the negative electrode of the traction rectifier unit 600 are sequentially connected to form an electrical circuit to provide electrical energy for the train;

[0098] The grounding conduction device 100 is arranged between the running rail 603 and the negative pole of the traction rectifier unit 600; wherein the input end of the grounding conduction device is connected to the running rail, and the output end of the grounding conduction device is connected to the negative pole of the traction rectifier unit.

[0099] It should be noted that the traction rectifier unit 600 is located at the traction substation side.

[0100] Specifically, in the embodiment of the present application, the grounding conduction device is arranged between the running rail and the negative pole of the traction rectifier unit, wherein the running rail is connected to the grounding grid at each station. The return rail is connected to the negative pole of the traction rectifier unit. By arranging the grounding conduction device between the running rail and the negative pole of the traction rectifier unit, it can be ensured that in the DC traction power supply system, current can only flow from the running rail to the negative pole of the traction rectifier unit, and the current is prevented from flowing from the return rail through the running rail and the grounding grid to the ground terminal, generating stray current.

[0101] When one or more diodes in the grounding conduction device are in an abnormal state, the controller will disconnect the first switch connected in series with the one or more diodes to ensure that the current only flows from the running rail to the negative pole of the traction rectifier unit. In the grounding conduction device, the current of the second shunt is mainly used to determine the interval where the positive pole of the traction rectifier unit leaks current to the ground; or to determine the interval where the negative pole of the traction rectifier unit leaks current to the ground. In addition, in order to avoid damage to the equipment when operating the second switch under load, the second shunt is also used to lock the operation of the second switch. For example, when the grounding conduction device is applied to the power supply system of rail transit, the second switch can be disconnected when the rail transit is under maintenance, thereby realizing the switching of the grounding conduction device between the maintenance state and the working state by controlling the connection or disconnection of the second state.

[0102] In an optional embodiment of the present application, a plurality of grounding conduction devices 100 are arranged between the running rail 603 and the negative pole of the traction rectifier unit 600; wherein the input end of the grounding conduction device is connected to the running rail, and the output end of the grounding conduction device is connected to the negative pole of the traction rectifier unit.

[0103] Specifically, in the embodiment of the present application, a plurality of grounding conduction devices are provided between the running rail and the negative pole of the traction rectifier unit, and the grounding conduction devices are installed in sections according to the actual need to limit the fault range.

[0104] In an optional implementation manner of the present application, the current of the second shunt in two or more grounding conduction devices 100 among the multiple grounding conduction devices 100 is used to determine the interval in which the contact network 601 or the return rail 602 generates leakage current to the ground.

[0105] Specifically, the controller in each grounding conduction device detects the current value of the second shunt in the device and sends the detected current value to the power monitoring center of the DC traction power supply system. The power monitoring center can detect the leakage of the return rail or the negative pole of the DC traction power supply system to the ground by comparing the currents of the second shunts in multiple grounding conduction devices, and determine the interval where the current leakage occurs from the negative pole of the return rail or the traction rectifier unit to the ground. In addition, by comparing the currents in the second shunts in multiple grounding conduction devices, the interval where the contact network generates leakage current to the ground can also be determined.

[0106] In an optional implementation manner of the present application, the DC traction power supply system further includes: a feeder protection circuit 605; wherein,

[0107] The feeder protection circuit 605 is disposed between the traction rectifier unit 600 and the contact network 601, and is used to cut off the current between the contact network 601 and the ground when the contact network 601 is short-circuited to the ground.

[0108] The embodiment of the present application utilizes the running rail and the ground as the short-circuit current path without destroying the protection performance of the return rail against stray current, relies on the feeder protection circuit to cut off the fault, has good protection for the DC traction power supply system, and does not need to change the traditional protection configuration and setting scheme.

[0109] Specifically, the DC traction power supply system of the embodiment of the present application also includes a feeder protection circuit, which includes a circuit breaker body large current trip protection, current quick-break protection, overcurrent protection, and current increment protection (di / dt+ΔI). The feeder protection circuit is set with a reasonable setting value. By setting the feeder protection circuit between the traction rectifier unit and the contact network, the return rail is also connected to the ground through the grounding conduction device and the running rail. When the contact network is short-circuited to the ground, a complete current path will be formed between the positive pole of the traction rectifier unit, the feeder protection circuit, the contact network, the ground, the running rail, the grounding conduction device, and the negative pole of the traction rectifier unit. At this time, by disconnecting the feeder protection circuit, the current between the contact network and the ground can be cut off, which plays a role in leakage protection in the DC traction power supply system. At the same time, since the feeder protection circuit and grounding conduction device in the DC traction power supply system are segmented according to the need to limit the fault range, when the feeder protection circuit is in the disconnected state, only the faulty section of the system is cut off, avoiding full line tripping caused by partial faults in the system, thereby improving the safety and reliability of system operation.

[0110] In an optional embodiment of the present application, the system includes multiple sections of running rails 603, and the multiple sections of running rails 603 are connected by cables 606 to form a passage; wherein the passage formed by the multiple sections of running rails 603 is connected to the ground or each section of the multiple sections of running rails 603 is connected to the ground.

[0111] Specifically, when installing the running rails, it is necessary to connect the running rails installed in sections through connecting cables to form a circuit that is electrically connected throughout the entire line. The running rails in the track generally use running steel rails, and the running rails installed in sections are connected to the grounding grid at each station.

[0112] In an optional embodiment of the present application, the running rail 603 is connected to the structural steel bars and shielding doors of the platform at the station with the same potential; or, the running rail 603 is connected to the structural steel bars and safety doors of the platform at the station with the same potential.

[0113] Specifically, the running rail is connected to the structural steel bars and shielding doors of the platform at the station with the same potential; or, the running rail is connected to the structural steel bars and safety doors of the platform at the station with the same potential. This prevents electric shock to passengers due to the existence of step voltage and ensures the personal safety of passengers.

[0114] It should be noted that in the embodiments of the present application, the running rails can be installed in an insulating manner or in a non-insulating manner. When non-insulating installation is adopted, no special measures are required to meet the insulation strength requirements of the running rails. However, during the implementation of the project, insulating installation is sometimes adopted due to the needs of track installation. However, when the running rails are installed in an insulating manner, no special requirements are made on the insulation strength.

[0115] The DC traction power supply system provided in the embodiment of the present application can prevent the current in the return rail from flowing to the ground to generate stray current by arranging a grounding conduction device between the running rail and the negative pole of the traction rectifier unit. At the same time, a complete current path can be formed between the positive pole of the traction rectifier unit, the feeder protection circuit, the contact network, the ground, the running rail, the grounding conduction device, and the negative pole of the traction rectifier unit. When the contact network is short-circuited to the ground to generate current leakage, the current between the contact network and the ground is cut off through the feeder protection circuit, thereby providing leakage protection for the DC traction power supply system. At the same time, since the feeder protection circuit and the grounding conduction device in the DC traction power supply system are segmented according to the need to limit the fault range, when the feeder protection circuit is in the disconnected state, only the faulty part of the system is cut off, thereby avoiding large-scale tripping caused by partial faults, thereby improving the safety and reliability of system operation.

[0116] The technical solutions described in the embodiments of the present application can be combined arbitrarily without conflict.

[0117] In the several embodiments provided in the present application, it should be understood that the disclosed methods and intelligent devices can be implemented in other ways. The device embodiments described above are merely schematic. For example, the division of the units is only a logical function division. There may be other division methods in actual implementation, such as: multiple units or components can be combined, or can be integrated into another system, or some features can be ignored or not executed. In addition, the coupling, direct coupling, or communication connection between the components shown or discussed can be through some interfaces, and the indirect coupling or communication connection of the devices or units can be electrical, mechanical or other forms.

[0118] The units described above as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units; some or all of the units may be selected according to actual needs to achieve the purpose of the present embodiment.

[0119] In addition, all functional units in the embodiments of the present application may be integrated into a second processing unit, or each unit may be a separate unit, or two or more units may be integrated into one unit; the above-mentioned integrated units may be implemented in the form of hardware or in the form of hardware plus software functional units.

[0120] The above description is only a specific implementation manner of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application.

Claims

1. A grounding conduction device, characterized in that: The device comprises a plurality of first branches and a controller; the plurality of first branches are connected in parallel; wherein, The controller is connected to each of the plurality of first branches, and is used to control each of the plurality of first branches to be in an on state or an off state; The device also includes a second branch having a third end and a fourth end; The second branch includes a second shunt and a second switch, wherein the second shunt and the second switch are connected in series in any manner; The third end of the second branch is connected to the second end of each of the plurality of first branches; the fourth end of the second branch constitutes the output end of the ground connection device; The controller is connected to the second shunt and is used to detect the current in the second shunt; The controller is connected to the second switch and is used to control the state of the second switch.

2. The device according to claim 1, characterized in that Each of the plurality of first branches has a first end and a second end; Each of the plurality of first branches comprises a diode, a first switch and a first shunt; wherein the diode, the first switch and the first shunt in each of the first branches are connected in series in any order; The first end of each of the plurality of first branches is connected in parallel to form an input end of the ground connection device; The controller is connected to the first shunt in each first branch, and is used to detect the current of the first shunt in each first branch, and determine whether the current of the first shunt in each first branch exceeds a set current threshold, wherein the current threshold is set to indicate that the current when the diode connected in series with the first shunt is in a breakdown state; The controller is also connected to the first switch in each of the first branches, and is used to control the state of the first switch in each of the first branches according to the detected current of the first shunt in each of the first branches.

3. The device according to claim 2, characterized in that The diode, the first switch and the first shunt are connected in series in any order, including: The diode, the first switch and the first shunt are connected in series in sequence; or, The diode, the first shunt and the first switch are connected in series in sequence; or, The first switch, the diode and the first shunt are connected in series in sequence; or, The first switch, the first shunt and the diode are connected in series in sequence; or, The first shunt, the diode and the first switch are connected in series in sequence; or, The first shunt, the first switch and the diode are connected in series in sequence.

4. The device according to claim 2, characterized in that The serial connection mode of the internal components of different first branches in the plurality of first branches is the same; or, Different first branch internal components in the plurality of first branches are connected in series in different ways; Wherein, the internal components include the diode, the first switch and the first shunt.

5. The device according to claim 1, characterized in that The second shunt and the second switch are connected in series in any manner, including: The second switch and the second shunt are connected in series in sequence; or, The second shunt and the second switch are connected in series in sequence.

6. The device according to claim 1 or 5, characterized in that The input end of the grounding conductive device is grounded, and the output end of the grounding conductive device is connected to a negative electrode.

7. A DC traction power supply system, characterized in that: The system comprises a traction rectifier unit, a contact network, a return rail, a running rail and a grounding network, and a grounding conduction device according to any one of claims 1 or 5 to 6; wherein, The positive electrode of the traction rectifier unit, the overhead line, the train, the return rail and the negative electrode of the traction rectifier unit are sequentially connected to form an electrical circuit to provide electrical energy for the train; The grounding conduction device is arranged between the running rail and the negative pole of the traction rectifier unit.

8. The system according to claim 7, characterized in that A plurality of grounding conduction devices are arranged between the running rail and the negative pole of the traction rectifier unit; wherein the input end of the grounding conduction device is connected to the running rail, and the output end of the grounding conduction device is connected to the negative pole of the traction rectifier unit.

9. The system according to claim 7, characterized in that The current of the second shunt in more than two of the multiple grounding conduction devices is used to determine the interval in which the contact network or the return rail generates leakage current to the ground.

10. The system according to claim 7, characterized in that The DC traction power supply system further includes: a feeder protection circuit; wherein, The feeder protection circuit is arranged between the positive pole of the traction rectifier unit and the contact network, and is used to cut off the current between the contact network and the ground when the contact network is short-circuited to the ground.

11. The system according to claim 7, characterized in that The system includes multiple sections of running rails, which are connected by cables to form a passage; wherein the passage formed by the multiple sections of running rails is connected to the ground or each section of the multiple sections of running rails is connected to the ground.

12. The system according to claim 7, characterized in that The installation method of the running rail is non-insulated installation.

13. The system according to claim 7, characterized in that The running rail is connected to the structural steel bars and the shielding door of the platform at the station with the same potential; or, the running rail is connected to the structural steel bars and the safety door of the platform at the station with the same potential.

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