Intelligent backflow rail grounding device

Abstract

The utility model discloses an intelligent backflow rail grounding device which comprises a main direct current contactor, a diverter and a controller, one end of a main contact of the main direct current contactor is connected with one end of the diverter, the other end of the main contact of the main direct current contactor is connected to a grounding busbar, and the other end of the diverter is connected to a backflow rail or a backflow box. Two ends of the shunt are connected to a current detection end of the controller through a current transmitter, the other end of the shunt and the other end of a main contact of the main direct current contactor are respectively connected to a voltage detection end of the controller through a voltage transmitter, and a control contact of the main direct current contactor is connected with a contactor control end of the controller. According to the scheme, through the control design of the controller, the problems that the service life of equipment is shortened due to frequent action of a potential limiting device and normal operation of a subway is affected due to high sensitivity of three-section protection in the prior art are solved, and the beneficial effects of reducing material and operation and maintenance cost and prolonging the service life are achieved.

Description

Technical Field

[0001] This application relates to the technical field of equipment for the traction power supply system of urban rail transit trains, and specifically to an intelligent return rail grounding device. Background Art

[0002] The core function of the rail potential limiting device is to monitor and limit the potential difference between the rail and the ground in real time to ensure it is within a safe range. The device precisely measures the rail-to-ground potential through a voltage detection unit. Once the detected voltage exceeds the preset value, the device will be quickly activated to short-circuit the rail to the ground, thus effectively suppressing the potential increase. This design not only ensures the personal safety of passengers when getting on and off the train but also prevents equipment from being damaged due to high voltage. Under normal operating conditions, when the train starts or runs, the traction current flowing through the rail will cause the rail-to-ground potential to rise to a positive or negative value. At this time, the rail potential limiting device will start three-stage protection according to the negative ground voltage. The third-stage protection is that the thyristor quickly turns on, and then the contactor closes to ensure that the rail potential is limited within a safe range. However, in actual working conditions, it is often encountered that the increase in negative ground voltage causes the device to act frequently. The three-stage protection will trigger the thyristor to conduct, and the frequent operation of the equipment reduces the service life of the equipment and increases the frequency of personnel inspection and maintenance. In addition, the high sensitivity of the three-stage protection may cause the device to malfunction under non-fault conditions, affecting the normal operation of the subway. Summary of the Invention

[0003] Aiming at the problems of the existing technology that the potential limiting device acts frequently, reducing the service life of the equipment, and the high sensitivity of the three-stage protection affecting the normal operation of the subway, this application provides an intelligent return rail grounding device to solve the above problems.

[0004] To achieve the above objectives, the present application is implemented through the following technical solutions: An intelligent return rail grounding device includes a main DC contactor, a shunt, a measurement amplifier, and a controller. One end of the main contact of the main DC contactor is connected to one end of the shunt, and the other end is connected to the grounding busbar. The other end of the shunt is connected to the return rail or the return box. The measurement amplifier includes a current transmitter and a voltage transmitter. The two ends of the shunt are connected to the current detection end of the controller through the current transmitter, and the other end of the shunt and the other end of the main contact of the main DC contactor are respectively led to the voltage detection end of the controller through the voltage transmitter. The control contact of the main DC contactor is connected to the contactor control end of the controller. The controller is used to detect the voltage difference Ub between the rail and the ground through the voltage transmitter, and when Ub is greater than the operating voltage Ua, control the main DC contactor to close after a first delay time Ta, and after a second delay time Tb, when the current detected by the current detection end of the controller is lower than the breaking current setting value Ia, automatically restore to the open state. When the controller detects that the main DC contactor has continuously operated a specified number of times within a specified time Tc, control the main DC contactor not to automatically restore to the open state but to remain in the closed state and provide an alarm signal.

[0005] Preferably, a secondary DC contactor is also connected between the control contact of the main DC contactor and the contactor control end of the controller, and the secondary DC contactor is a low-voltage DC contactor.

[0006] Preferably, the breaking current setting value is 10A ≤ Ia ≤ 1500A.

[0007] Preferably, the operating voltage is 30V ≤ Ua < Ub, and the number of adjustment segments of Ua is not less than 8 segments, and each adjustment step is not greater than 1V.

[0008] Preferably, the voltage difference between the rail and the ground is 350V ≤ Ub ≤ 600V.

[0009] Preferably, the first delay time is 0s < Ta ≤ 300s, and each adjustment step is not greater than 0.05s.

[0010] Preferably, the second delay time is 1s ≤ Tb ≤ 300s, and each adjustment step is not greater than 1s.

[0011] Preferably, the specified time is 0.1min ≤ Tc ≤ 30min, and each adjustment step is not greater than 0.1min.

[0012] Preferably, the controller performs wave recording before and after the main DC contactor closes, records current and voltage signals, and the controller is also connected to a stray current monitoring system for uploading communication, and the wave recording data is output in the form of waveforms.

[0013] Preferably, the controller is also communicatively connected to the substation integrated automation system for remote control and remote signaling of the controller.

[0014] The intelligent return rail grounding device provided by this solution solves the problems in the prior art that the potential limiting device frequently operates, reducing the service life of the equipment, and the high sensitivity of the three-section protection affects the normal operation of the subway. It realizes the multi-section protection function, avoids misoperation under non-fault conditions, ensures the normal operation of the subway, and at the same time makes the device lightweight, reduces the main components, and lowers the equipment cost. It can also monitor the negative pole-to-ground voltage and provide monitoring data to the stray current monitoring system. When used in conjunction with the stray current system, the added remote signaling and remote control solutions of this device reduce the on-site maintenance frequency and cost of the operation personnel. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a schematic diagram of the composition of an embodiment of the intelligent return rail grounding device of this application;

[0016] Among them, 1 - main DC contactor, 2 - shunt, 3 - current transmitter, 4a - first voltage transmitter, 4b - second voltage transmitter, 5 - controller, 6 - auxiliary DC contactor. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0017] Next, the technical solutions in the embodiments of this application will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of this application. Obviously, the described embodiments are only a part of the embodiments of this application, rather than all the embodiments.

[0018] This embodiment provides a technical solution: a device including a main DC contactor 1, a shunt 2, a measuring amplifier, and a controller 5. One end of the main contact of the main DC contactor 1 is connected to one end of the shunt 2, and the other end is connected to the grounding busbar. The other end of the shunt 2 is connected to the return rail or return box. The measuring amplifier includes a current transducer 3 and a voltage transducer. Both ends of the shunt 2 are connected to the current detection end of the controller 5 through the current transducer 3. The other end of the shunt 2 and the other end of the main contact of the main DC contactor 1 are respectively led to the voltage detection end of the controller 5 through the voltage transducer. In this embodiment, two voltage transducers with different applicable ranges are used to access the two voltage detection ends of the controller 5, namely the first voltage transducer 4a applicable to ±150V and the second voltage transducer 4b applicable to ±1000V. The control contact of the main DC contactor 1 is connected to the contactor control end of the controller 5. The controller 5 is used to detect the voltage difference Ub between the rail and the ground through the voltage transducer, and when Ub is greater than the operating voltage Ua, control the main DC contactor 1 to close after a first delay time Ta, and after a second delay time Tb, when the current detected by the current detection end of the controller 5 is lower than the breaking current setting value Ia, automatically restore to the open state. When the controller 5 detects that the main DC contactor 1 continuously operates a specified number of times within a specified time Tc, control the main DC contactor 1 not to automatically restore to the open state but to remain in the closed state and provide an alarm signal. Once Ua and Ub are set, their setting values will not shift due to the frequent operation of the contactor or other reasons. When the control power is lost, the contactor closes and remains in the closed state.

[0019] In this embodiment, a secondary DC contactor 6 is also connected between the control contact of the main DC contactor 1 and the contactor control end of the controller 5. The secondary DC contactor 6 is a low-voltage DC contactor to ensure the matching of the current-carrying capacity of the contacts.

[0020] The breaking current setting value satisfies 10A ≤ Ia ≤ 1500A, the operating voltage satisfies 30V ≤ Ua < Ub, the number of adjustment segments of Ua is not less than 8 segments, and each adjustment step is not greater than 1V. The voltage difference between the rail and the ground satisfies 350V ≤ Ub ≤ 600V. The first delay time satisfies 0s < Ta ≤ 300s, and each adjustment step is not greater than 0.05s. The second delay time satisfies 1s ≤ Tb ≤ 300s, and each adjustment step is not greater than 1s. The specified time satisfies 0.1min ≤ Tc ≤ 30min, and each adjustment step is not greater than 0.1min.

[0021] The controller 5 performs wave recording before and after the main DC contactor 1 is closed, records current and voltage signals, and outputs the wave recording data in the form of waveforms. The total time of wave recording is not less than 10 minutes, the time recorded before the main DC contactor 1 is closed is not less than 5 minutes, the time recorded after closing is not less than 5 minutes, the recording time before and after closing is adjustable, and the sampling interval for closing wave recording is not greater than 1 ms.

[0022] In this embodiment, the current transmitter 3 and the first voltage transmitter 4a have an accuracy of ±0.3%, and can monitor the negative pole to ground voltage and current. In another embodiment, the controller 5 can also be connected to a stray current monitoring system for uploading communication. The controller 5 uploads the real-time measurement values to the stray current monitoring system, and the stray current monitoring system analyzes the stray current condition through continuous monitoring data analysis and can quickly detect insulation faults, so as to take measures to avoid corrosion damage of the equipment inside and outside the system caused by stray current.

[0023] The controller 5 is also communicatively connected to the substation integrated automation system. The connection interface can be one of fieldbus, Ethernet or optical fiber, and the communication protocol can be one of FTP, Modbus, IEC60870-5-104, IEC61850, etc. The fault recording waveform file can be viewed locally through special software and equipment, and the time value, voltage value and current value corresponding to each point of the waveform curve can be viewed. It can also be downloaded from the device of this application and uploaded by remote call. The waveform curve and event record can be viewed in the background, so that the operators can monitor the equipment in real time and analyze faults. The current Ia, each voltage and each time parameter setting value in the controller 5 can be modified through communication. The operators can modify the protection setting value remotely according to the actual working conditions. Through the communication method, the operation status and data of the real-time monitoring device can be monitored, and the closing and opening of the short-circuit device contactor can be remotely controlled to ensure remote switching-on and switching-off operations when needed. The above-mentioned remote signaling and remote control functions reduce the on-site maintenance frequency of personnel and reduce the operation and maintenance time and cost.

[0024] In the description of this application, it should be noted that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing this application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation to this application. In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0025] As described above, it is only the preferred specific implementation manner of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present application, according to the technical solution and inventive concept of the present application, making equivalent substitutions or changes should be covered by the protection scope of the present application.

Claims

1. An intelligent return rail grounding device, characterized in that: It includes a main DC contactor (1), a shunt (2), a measuring amplifier, and a controller (5). One end of the main contact of the main DC contactor (1) is connected to one end of the shunt (2), and the other end is connected to the grounding busbar. The other end of the shunt (2) is connected to the return rail or the return box. The measuring amplifier includes a current transmitter (3) and a voltage transmitter. Both ends of the shunt (2) are connected to the current detection end of the controller (5) through the current transmitter (3). Wires are respectively led from the other end of the shunt (2) and the other end of the main contact of the main DC contactor (1) and connected to the voltage detection end of the controller (5) through the voltage transmitter. The control contact of the main DC contactor (1) is connected to the contactor control end of the controller (5). The controller (5) is used to detect the voltage difference Ub between the rail and the ground through the voltage transmitter, and when Ub is greater than the operating voltage Ua, control the main DC contactor (1) to close after a first delay time Ta, and after delaying for a second delay time Tb, when the current detected at the current detection end of the controller (5) is lower than the opening current setting value Ia, automatically resume opening. When the controller (5) detects that the main DC contactor (1) has continuously operated a specified number of times within a specified time Tc, control the main DC contactor (1) not to automatically resume opening but to be in a closed state and provide an alarm signal.

2. The intelligent return rail grounding device according to claim 1, characterized in that: A secondary DC contactor (6) is also connected between the control contact of the main DC contactor (1) and the contactor control end of the controller (5), and the secondary DC contactor (6) is a low-voltage DC contactor.

3. The intelligent return rail grounding device according to claim 1, characterized in that: The opening current setting value is 10A ≤ Ia ≤ 1500A.

4. The intelligent return rail grounding device according to claim 1, wherein: The operating voltage is 30V ≤ Ua < Ub, and the number of adjustment segments of Ua is not less than 8 segments, and each adjustment step is not greater than 1V.

5. The intelligent return rail grounding device according to claim 1, characterized in that: The voltage difference between the rail and the ground is 350V ≤ Ub ≤ 600V.

6. The intelligent return rail grounding device according to claim 1, characterized in that: The first delay time is 0s < Ta ≤ 300s, and each adjustment step is not greater than 0.05s.

7. An intelligent return rail grounding device according to claim 1, characterized in that: The second delay time is 1s ≤ Tb ≤ 300s, and each adjustment step is not greater than 1s.

8. An intelligent return rail grounding device according to claim 1, characterized in that: The specified time is 0.1min ≤ Tc ≤ 30min, and each adjustment step is not greater than 0.1min.

9. The intelligent return rail grounding device according to claim 1, wherein: The controller (5) performs wave recording before and after the main DC contactor (1) closes, records current and voltage signals, and the controller (5) can also be connected to the stray current monitoring system for uploading communication, and the wave recording data is output in the form of waveforms.

10. The intelligent return rail grounding device according to claim 1, wherein: The controller (5) is also communicatively connected to the substation integrated automation system for remote control and remote signaling of the controller (5).

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