Voltage type AC / DC live detection automatic grounding system

Abstract

The utility model relates to the technical field of power electronics, and discloses a voltage-type AC / DC live detection automatic grounding system. Comprising a positive bus, a negative bus, a transformer, a resistor, a Hall voltage sensor, a grounding switch and a detection master control device, the input end of the transformer is connected with the positive bus, the output end of the transformer is connected with the input end of the resistor, and the output end of the resistor is connected with the negative bus. The input end and the output end of the resistor are connected in parallel to the Hall voltage sensor; the grounding switch input end is connected with the positive bus, and the grounding switch output end is connected with the negative bus. The system can adapt to real-time live-line detection and automatic grounding of AC / DC voltages of AC 27.5 KV, DC 1500V and DC 750V, and real-time voltage display and AC / DC characteristic display under the live-line condition by installing only one set of device; the grounding knife switch is automatically switched on, safety accidents and misoperation in the manual electricity testing and switching-on process are avoided, and the safety of the grounding working condition of a locomotive traction power supply system is effectively improved.

Description

Technical Field

[0001] The utility model belongs to the technical field of power electronics, and in particular relates to a voltage-type AC / DC live detection automatic grounding system for rail transit contact network. Background Art

[0002] The rapid development of rail transit has spurred the establishment of numerous locomotive manufacturers, each equipped with dedicated lines for dynamic locomotive commissioning. Current locomotive commissioning plants typically use the same commissioning power supply line for DC 1500V, DC 750V, and AC 27.5kV. After locomotive commissioning, the power supply line must be grounded to ensure safety. Before grounding, a live line test is performed to ensure the system is de-energized. This current approach presents two major issues. First, because mixed AC and DC lines require separate test poles, manual operation can lead to breakdown or inaccurate testing, potentially causing safety incidents. Second, even if the line is energized during the test, the current real-time voltage cannot be accurately displayed. Second, since the grounding switch must be manually closed after the test, there is a risk of misplaced or incomplete grounding, posing a safety hazard. Utility Model Content

[0003] In view of the shortcomings of the existing technology, the purpose of the utility model is to provide a voltage-type AC / DC live detection automatic grounding system, which solves the operational risks in the process of power testing and grounding knife closing.

[0004] In order to achieve the above purpose, the present invention is implemented through the following technical solutions:

[0005] A voltage-type AC / DC live detection automatic grounding system includes a positive bus, a negative bus, a transformer, a resistor, a Hall current sensor, a grounding switch, and a detection main control device. The input end of the transformer is connected to the positive bus, the output end of the transformer is connected to the input end of the resistor, the output end of the resistor is connected to the negative bus, and a Hall voltage sensor is connected in series between the output end of the resistor and the negative bus.

[0006] The input end of the grounding switch is connected to the positive bus, and the output end of the grounding switch is connected to the negative bus;

[0007] The input end of the detection main control device collects the current signal of the Hall voltage sensor and the voltage signal output by the secondary side of the transformer, and the output end controls the opening and closing of the grounding switch.

[0008] Furthermore, the Hall voltage sensor is used to collect the real-time voltage across the resistor.

[0009] Furthermore, when the system input voltage is DC1500V or DC750V, the transformer in the system has no inductive reactance effect on DC, only its own impedance.

[0010] Furthermore, when the system input voltage is AC27.5kV, the transformer outputs the secondary side voltage, and the resistor and the primary side of the transformer divide the system voltage; the real-time voltage of the resistor and the secondary side input voltage of the transformer are collected through the Hall voltage sensor.

[0011] Furthermore, the detection main control device includes a control output module, an AC voltage sampling module, a Hall voltage sampling module, a display module and a microcontroller MCU.

[0012] Compared with the prior art, the beneficial effects of the present invention are:

[0013] The utility model realizes automatic live detection of AC and DC voltages. Only one set of devices is required to adapt to real-time live detection and automatic grounding of AC and DC voltages of AC27.5KV, DC1500V and DC750V, as well as real-time voltage display and AC and DC characteristic display under live conditions. It realizes automatic closing of the grounding knife, avoids safety accidents and misoperation during manual power testing and closing, and effectively improves the safety of the grounding working condition of the locomotive traction power supply system. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a structural diagram of the utility model;

[0015] Figure 2 This is a control flow chart of the utility model;

[0016] Among them: 1. Positive bus; 2. Negative bus; 3. Transformer; 4. Resistor; 5. Hall voltage sensor; 6. Grounding switch; 7. Detection main control device. DETAILED DESCRIPTION

[0017] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0018] The present invention will be further described with reference to the accompanying drawings and embodiments:

[0019] Example 1:

[0020] A voltage-type AC / DC live detection automatic grounding system, reference Figure 1-Figure 2As shown, it includes a positive bus 1, a negative bus 2, a transformer 3, a resistor 4, a Hall voltage sensor 5, a grounding switch 6 and a detection main control device 7;

[0021] The input end of the transformer 3 is connected to the positive bus 1, the output end of the transformer 3 is connected to the input end of the resistor 4, the output end of the resistor 4 is connected to the negative bus 2, and a Hall voltage sensor 5 is connected in series between the output end of the resistor 4 and the negative bus 2;

[0022] The input end of the grounding switch 6 is connected to the positive bus 1, and the output end of the grounding switch 6 is connected to the negative bus 2;

[0023] The input end of the detection main control device 7 collects the current signal of the Hall voltage sensor 5 and the voltage signal output by the secondary side of the transformer 3, and the output end controls the opening and closing of the grounding switch 6.

[0024] In this embodiment, the detection main control device 7 includes a control output module, an AC voltage sampling module, a Hall voltage sampling module, a display module, a controller and a microcontroller MCU;

[0025] Specifically, the control output module includes an optocoupler isolation circuit, a MOSFET drive circuit and a high-voltage relay; the optocoupler isolation circuit isolates the control signal of the microcontroller MCU from the high-voltage circuit to prevent strong electrical interference from affecting the control signal; the MOSFET drive circuit amplifies the power of the isolated signal to provide sufficient drive current for the high-voltage relay; the high-voltage relay acts as an actuator to directly control the opening and closing actions of the grounding knife 6.

[0026] This module receives control commands from the microcontroller MCU and, based on system detection results, controls the high-voltage relay contacts to close or open, thereby opening and closing the grounding switch 6. When the system detects a bus voltage drop and, after a certain delay, no voltage input, it drives the high-voltage relay to close the grounding switch 6, completing the grounding and preventing the bus from energizing again. Upon receiving a request to energize the bus, the system drives the high-voltage relay to open the grounding switch 6.

[0027] Specifically, the AC voltage sampling module includes a voltage transformer, a signal conditioning circuit, and an A / D converter module. The voltage transformer isolates and steps down the AC voltage output from the secondary side of transformer 3, ensuring the safety of the sampled signal. The signal conditioning circuit filters, amplifies, and adjusts the bias of the stepped-down signal, converting it into a DC signal suitable for processing by the A / D converter module. The A / D converter module converts the analog signal into a digital signal for processing by the microcontroller (MCU).

[0028] This module collects the AC voltage signal from the secondary side of transformer 3 in real time and, after processing and conversion, provides the system with accurate AC voltage data. By analyzing the AC voltage signal, it can determine the system's AC power supply status and voltage amplitude anomalies, providing key evidence for fault diagnosis.

[0029] Specifically, the Hall voltage sampling module includes a signal amplification circuit and a linear optocoupler isolation circuit; the signal amplification circuit amplifies the weak signal output by the Hall voltage sensor 5; the linear optocoupler isolation circuit electrically isolates the amplified signal to prevent common-mode interference, and at the same time transmits the signal to the microcontroller MCU.

[0030] The module can quickly respond to voltage changes and provide the system with real-time and accurate voltage data, helping the microcontroller MCU determine whether the system has abnormal conditions such as overvoltage and undervoltage;

[0031] Specifically, the display module uses an LCD screen to intuitively display system operating parameters such as busbar voltage, transformer 3 secondary voltage, and grounding switch 6 status. It also displays fault information in real time, including the type and time of occurrence of overvoltage, undervoltage, and grounding faults. The touchscreen allows for system parameter settings and historical data query, enhancing user convenience. The display module provides real-time information on various system parameters, such as current level and grounding switch 6 status, facilitating system monitoring and operation. Furthermore, when a system fault occurs, the display module promptly displays the fault type and related information, helping maintenance personnel quickly locate and troubleshoot the problem.

[0032] Specifically, the microcontroller MCU is the core of the detection main control device 7, which receives digital signals from the AC voltage sampling module and the Hall voltage sampling module, and performs filtering, calculation, analysis and other processing; judges the system operation status based on preset thresholds and algorithms, and outputs control instructions to the control output module; manages the display content and operation interaction of the display module; realizes data interaction with the host computer through the communication interface, uploads detection data and receives remote control instructions.

[0033] In this embodiment, the transformer 3 has a transformation ratio of N, a self-impedance of Rr0, and an impedance of Rr1 of the resistor 4. The characteristic of the transformer 3 that it blocks AC and passes DC is used.

[0034] like Figure 1 As shown, the output end of the resistor 4 is connected in parallel to the Hall voltage sensor 5 for collecting the real-time voltage across the resistor 4 .

[0035] When the system input voltage is DC1500V or DC750V, the transformer 3 in the system has no inductive reactance effect on DC, only its own impedance Rr0. Therefore, the real-time voltage U2 collected by the Hall voltage sensor 5 is used to calculate the current DC current I flowing through the transformer: I = U2 ÷ Rr1;

[0036] The DC voltage of transformer 3 is U1=I×Rr0= (U2÷Rr1)×Rr0;

[0037] The total system bus voltage U is: U=U1+U2=(U2÷Rr1)×Rr0+U2;

[0038] The control system determines that the DC is energized and displays the real-time DC voltage.

[0039] When the system input voltage is AC27.5kV, transformer 3 outputs the secondary voltage, and resistor 4 and the primary side of transformer 3 divide the system voltage. Therefore, the sum of the resistor's real-time voltage U2, collected by Hall effect voltage sensor 5, and transformer 3's secondary input voltage U1, constitutes the total system voltage. The current total system bus voltage U is calculated as: U = U1 + U2. The system determines that the AC is live and displays the real-time voltage.

[0040] If the total system bus voltage is not zero, the system prohibits the grounding switch from closing. If the total system bus voltage is zero, the grounding switch will automatically close after a delay.

[0041] The above shows and describes the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions are merely illustrative of the principles of the present invention. Various changes and improvements may be made to the present invention without departing from the spirit and scope of the present invention. Such changes and improvements are intended to fall within the scope of the present invention. The scope of protection claimed in the present invention is defined by the appended claims and their equivalents.

Claims

1. A voltage-type AC / DC live detection automatic grounding system, characterized in that: It includes a positive bus, a negative bus, a transformer, a resistor, a Hall current sensor, a grounding switch and a detection main control device. The input end of the transformer is connected to the positive bus, the output end of the transformer is connected to the input end of the resistor, the output end of the resistor is connected to the negative bus, and a Hall voltage sensor is connected in series between the output end of the resistor and the negative bus. The input end of the grounding switch is connected to the positive bus, and the output end of the grounding switch is connected to the negative bus; The input end of the detection main control device collects the current signal of the Hall voltage sensor and the voltage signal output by the secondary side of the transformer, and the output end controls the opening and closing of the grounding switch.

2. A voltage-type AC / DC live detection automatic grounding system according to claim 1, characterized in that: The Hall voltage sensor is used to collect the real-time voltage across the resistor.

3. A voltage-type AC / DC live detection automatic grounding system according to claim 1, characterized in that: When the system input voltage is DC1500V or DC750V, the transformer in the system has no inductive reactance effect on DC, only its own impedance.

4. A voltage-type AC / DC live detection automatic grounding system according to claim 1, characterized in that: When the system input voltage is AC27.5kV, the transformer outputs the secondary side voltage, and the resistor and the primary side of the transformer divide the system voltage; the real-time voltage of the resistor and the secondary side input voltage of the transformer are collected through the Hall voltage sensor.

5. The voltage-type AC / DC live detection automatic grounding system according to claim 1, characterized in that: The detection main control device includes a control output module, an AC voltage sampling module, a Hall voltage sampling module, a display module and a microcontroller MCU.

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