Power supply arm branch fault detection terminal

Abstract

The utility model belongs to the technical field of railway line detection, and particularly relates to a power supply arm branch fault detection terminal which comprises a Rogowski coil and a box body, the Rogowski coil is installed on a cable to be detected, and the cable to be detected is located at the center position of the Rogowski coil; the box body is fixedly installed on a power supply arm cable or a supporting column, a circuit board and a lithium battery are arranged in the box body, a circuit structure is arranged on the circuit board, the circuit structure comprises a main control module, a communication module, a trigger module and a power supply module, and the power supply module provides power management for the power supply arm branch fault detection terminal. The Rogowski coil is connected with the main control module through the trigger module; the Rogowski coil detects the current of the power supply arm to be detected, the main control module collects the detected current information and uploads the current information to the Internet of Things server through the communication module, and the trigger module provides timing trigger and external interruption trigger for the main control module. When the current of the power supply arm changes suddenly, the terminal can report the suddenly changed current to related personnel of a dispatching management center in time.

Description

Technical Field

[0001] The utility model belongs to the technical field of railway line detection, and in particular relates to a power supply arm branch fault detection terminal. Background Art

[0002] The power supply arm defines the power supply range in the railway power supply system. Understanding the operation status of the power supply arm as a whole is the basis for fault isolation and fault recovery. With the vigorous development of high-speed railways, the power supply arm, as a management unit in the railway power supply system, has received more attention. Therefore, higher requirements are put forward for the detection and response speed of the traction power supply arm. An effective means is needed to detect the status of the power supply arm, accurately cut off the fault line, protect the operation of the power supply arm, and meet the requirements of high-speed train traction stability and reliability. Summary of the invention

[0003] The purpose of the utility model is to solve the problems existing in the prior art and to propose a power supply arm branch fault detection terminal. When a sudden change occurs in the current of the power supply arm, it can report to the relevant personnel of the dispatching management center in time to reduce the occurrence of safety accidents.

[0004] To achieve the above purpose, the technical solution adopted is:

[0005] A power supply arm branch fault detection terminal, the terminal comprises a Rogowski coil and a box body, the Rogowski coil is installed on a cable to be tested, and the cable to be tested is located at the center of the Rogowski coil; the box body is fixedly installed on the power supply arm cable or support, and a circuit board and a lithium battery are arranged inside, a circuit structure is arranged on the circuit board, and the circuit structure comprises a main control module, a communication module, a trigger module and a power supply module, the power supply module provides power management for the power supply arm branch fault detection terminal, and the Rogowski coil is connected to the main control module through the trigger module; the Rogowski coil detects the current of the power supply arm to be tested, the main control module collects the detected current information, and uploads the current information to an Internet of Things server through the communication module, wherein the trigger module provides timing triggering and external interrupt triggering for the main control module.

[0006] According to the power supply arm branch fault detection terminal of the utility model, further, the model of the Rogowski coil is ZRC-50; the Rogowski coil is fixed to the outer circumference of the cable to be tested through a coil bracket.

[0007] According to the power supply arm branch fault detection terminal of the utility model, further, the main control module adopts an STM32L151RBT6 single-chip microcomputer, and the single-chip microcomputer is connected to a status indicator light, a SWD interface, a debugging UART interface, a watchdog circuit and a battery voltage collection circuit.

[0008] According to the power supply arm branch fault detection terminal of the utility model, further, the communication module selects the EC800 module, and its port is connected with the antenna interface, SIM card interface, USB interface and communication interface, and the communication interface communicates with the single-chip microcomputer through the level conversion chip.

[0009] According to the power supply arm branch fault detection terminal of the utility model, further, the trigger module includes an integration circuit, an analog-to-digital conversion circuit, a dual-threshold trigger circuit and a monostable circuit, the Rogowski coil is connected to the integration circuit through a coil interface, the output of the integration circuit is connected to the analog-to-digital conversion circuit on one side, converted into an SPI signal and then processed by the single-chip microcomputer, and is connected to the dual-threshold trigger circuit on the other side; the dual-threshold trigger circuit is connected to the single-chip microcomputer through the monostable circuit.

[0010] According to the power supply arm branch fault detection terminal of the utility model, further, the integration circuit adopts an M6LP chip, the analog-to-digital conversion circuit adopts an ADS7822 chip, the dual threshold trigger circuit adopts a TLV7032 chip, and the monostable circuit adopts an SN74LVC1G123 chip.

[0011] According to the power supply arm branch fault detection terminal of the utility model, further, the power supply module includes a charging management chip, and the charging management chip is respectively connected to the charging interface, the solar charging interface and the battery interface, the charging interface is connected to an external power supply, the solar charging interface is connected to the solar panel, and the battery interface is connected to the lithium battery.

[0012] According to the power supply arm branch fault detection terminal of the utility model, further, the power supply module also includes a switch interface connected to an external switch, the switch interface is arranged between the battery interface and the power conversion circuit, the power conversion circuit includes an LDO linear regulator and a DCDC buck-boost chip, the LDO linear regulator provides a 3V power supply for the microcontroller and the trigger module, and the DCDC buck-boost chip provides a 3.6V power supply for the communication module.

[0013] According to the power supply arm branch fault detection terminal of the utility model, further, the power supply module also includes a hysteresis comparator circuit, which is arranged between the switch interface and the LDO linear regulator.

[0014] According to the power supply arm branch fault detection terminal of the utility model, further, the charging management chip adopts a CN3791 chip.

[0015] The beneficial effects achieved by adopting the above technical solution are:

[0016] The utility model uses a high-precision Rogowski coil to detect the current of the traction power supply arm. When the current of the power supply arm changes suddenly, it can be reported to the relevant personnel of the dispatching management center in time, so as to take emergency measures in advance and prevent and reduce the occurrence of railway operation safety accidents. After the single-chip microcomputer wakes up at a fixed time or triggers the wake-up, it collects the current information of the power supply arm and uploads it to the Internet of Things server wirelessly. After completing the data transmission, it enters the sleep mode again to achieve the effect of low power consumption and energy saving. The terminal also supports solar charging and battery power supply, which further extends the battery life and improves the availability of the equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings of the embodiments of the present invention are briefly introduced below. The drawings are only used to show some embodiments of the present invention, but not to limit all embodiments of the present invention thereto.

[0018] Figure 1 It is a principle block diagram of a power supply arm branch fault detection terminal according to an embodiment of the utility model;

[0019] Figure 2 This is a battery voltage acquisition circuit diagram of an embodiment of the utility model;

[0020] Figure 3 It is an analog-to-digital conversion circuit diagram of an embodiment of the utility model;

[0021] Figure 4 It is an integration circuit diagram of an embodiment of the utility model;

[0022] Figure 5 This is a dual threshold trigger circuit diagram of an embodiment of the utility model;

[0023] Figure 6 It is a monostable circuit diagram of an embodiment of the utility model;

[0024] Figure 7 It is a waveform diagram of input and output signals of a monostable circuit of an embodiment of the utility model;

[0025] Figure 8 This is a circuit diagram of a power supply module of the utility model;

[0026] Fig. 9 It is a structural schematic diagram of the power supply arm branch fault detection terminal of the utility model, in which 1 is a cable, 2 is a metal waterproof box, 3 is an outer shell, 4 is a Rogowski coil, 5 is a fixing plate, and 6 is a coil bracket. DETAILED DESCRIPTION

[0027] The following will be combined with the drawings of the specific embodiments of the utility model to clearly and completely describe the exemplary scheme of the utility model. Unless otherwise defined, the technical terms or scientific terms used in the utility model should be the common meanings understood by people with ordinary skills in the field.

[0028] like Figure 1 and Fig. 9 As shown, the power supply arm branch fault detection terminal of this embodiment includes a Rogowski coil (current transformer can also be used) and a box body. The Rogowski coil collects alternating current with a frequency of 50Hz. The Rogowski coil is fixed to the outer circumference of the cable to be tested through a coil bracket, and the cable to be tested is at the center of the Rogowski coil. The optional installation method is: one end of the coil bracket clamps the Rogowski coil, and the other end is tied to the cable with a cable tie. The Rogowski coil model is ZRC-50 of Pinyan Company, which can test a maximum current of 500kA, and the current measurement error does not exceed 1%.

[0029] The box body is fixed to the 27.5KV power supply arm cable or pillar by fixing plates and bolts. The box body adopts an inner and outer two-layer structure design. The inner layer is a metal waterproof box, and the outer shell is divided into an upper and lower combined box. The outer shell is sealed to prevent water vapor from entering. The circuit board and lithium battery are installed inside the metal waterproof box. When assembling, first stick the lithium battery to the upper part of the metal waterproof box, stick foam on the bottom of the circuit board, and then push it into the metal waterproof box from the guide rail, which saves costs and facilitates installation.

[0030] A circuit structure is arranged on the circuit board, and the circuit structure includes a main control module, a communication module, a trigger module and a power supply module. The power supply module provides power management for the power supply arm branch fault detection terminal. The Roche coil is connected to the main control module through the trigger module. The Roche coil detects the current of the power supply arm to be tested. The main control module collects the detected current information and uploads the current information to the Internet of Things server through the communication module. The trigger module provides timing trigger and external interrupt trigger for the main control module.

[0031] The following is a detailed introduction to each unit module.

[0032] Main control module: The main control module uses ST's STM32L151RBT6 microcontroller to realize interrupt response, working and sleeping state control, EC800 power supply control and communication control, current data acquisition and processing. The microcontroller is connected with a status indicator, SWD interface, debug UART interface, watchdog circuit and battery voltage acquisition circuit. The battery voltage acquisition circuit realizes battery voltage acquisition through the microcontroller's support for analog sampling IO port voltage sampling, such as Figure 2As shown, the PC6 pin of the microcontroller enables the battery voltage acquisition circuit, and PB1 acquires the voltage analog signal of the battery voltage divided into 1 / 3, with 2.5V as the voltage reference. The PA1 and PC13-WUKP pins are used as external trigger interrupt wake-up pins; the PB14, PB13, and PB15 pins are used as power supply pins to control other modules, which can control the EC800 to enter the sleep state after power is turned off, and communicate with the EC800 module through the MAIN serial port. The analog signal is read by communicating with the ADS7822 chip through the SPI interface.

[0033] Communication module: The communication module uses the EC800 module of Shanghai Quectel Electronics Co., Ltd., which supports deep sleep mode. The ports are connected to the antenna interface, SIM card interface, USB interface, communication interface and debug interface. The antenna interface connects to the built-in antenna to realize wireless data transmission and reception. The IPEX socket can be used, and the FPC antenna is pasted on the inner wall of the metal waterproof box. The USB interface is used as a firmware upgrade interface, and the SIM card interface is used for SIM card access to provide CCID / SIM card number when dialing the EC800 module. The communication interface communicates with the microcontroller through the level conversion chip, and the debug interface can use a 3-pin small white socket to communicate with the external PC through the level conversion chip. The EC800 module uses the DCDC buck-boost chip TPS631000 to convert to 3.6V for power supply, and the low power consumption of the EC800 module is achieved by controlling the DCDC buck-boost chip to power off through the microcontroller.

[0034] Trigger module: The trigger module includes an integration circuit, an analog-to-digital conversion circuit, a dual-threshold trigger circuit and a monostable circuit. The Rogowski coil is connected to the integration circuit through the coil interface. One output of the integration circuit is connected to the analog-to-digital conversion circuit, which is converted into an SPI signal and then processed by the microcontroller. The other output is connected to the dual-threshold trigger circuit to detect 471A and 1424A transient currents respectively. The dual-threshold trigger circuit is connected to the microcontroller through a monostable circuit.

[0035] The integration circuit uses M6LP chip, such as Figure 4 As shown, the integration circuit outputs a 50Hz sine wave signal with a bias voltage of 1.25V. The corresponding relationship between the effective value of the signal and the current value collected by the Rogowski coil is:

[0036] Right now

[0037] V 有效值 The microcontroller reads the analog-to-digital conversion circuit through the SPI interface. The analog-to-digital conversion circuit is as follows Figure 3 As shown, the analog-to-digital conversion circuit uses the ADS7822 chip.

[0038] The integrator circuit can be used as a low-pass filter to filter high-frequency signals. The cut-off frequency of the low-pass filter is:

[0039]

[0040] Dual threshold trigger circuit such as Figure 5 As shown, the dual threshold trigger circuit adopts TLV7032 chip. When the collected current reaches the corresponding threshold, the corresponding INT1 and INT2 interrupt signals are output. The signal is a square wave signal with a frequency of 50Hz.

[0041] A threshold calculation: [2.5V*13.3K / (10K+13.3K)-1.25V]*1000 / 1.414 / 0.266=471A

[0042] B threshold calculation: [2.5V*18K / (7.15K+18K)-1.25V]*1000 / 1.414 / 0.266=1434A

[0043] When the current range is 0-471A, INT1 and INT2 are low-level signals. When the current range is 471-1424A, INT1 outputs a square wave signal and INT2 is a low-level signal. When the current exceeds 1424A, both INT1 and INT2 output square wave signals.

[0044] In order to facilitate the interrupt processing of the microcontroller IO interface, a monostable circuit is added, such as Figure 6 and Figure 7 As shown in the figure, the monostable circuit uses the SN74LVC1G123 chip. The square wave signal is delayed by no more than 20ms after passing through the circuit. The microcontroller is expected to wake up in 41ms from triggering, which meets the wake-up requirement within 170ms. The EC800 module is measured to be less than 10s from power-on to successful dialing, which meets the requirement of triggering the alarm delay of no more than 20s. The A pin needs to periodically input a low-level signal within 100mS, and the Q pin can stably output a high level to provide a stable interrupt signal to the microcontroller.

[0045] Power supply module: Figure 8As shown, the power supply module mainly realizes solar charging, external charging, power output control, switch control, etc. The power supply module includes a charging management chip, which is connected to the charging interface, solar charging interface and battery interface respectively. The charging interface is connected to the external power supply. The charging interface uses a waterproof DC charging socket (charging voltage is 12V) to realize external charging. It is located on the bottom of the metal waterproof box to effectively prevent rain from entering the box. The solar charging interface is connected to the solar panel, and the battery interface is connected to the lithium battery. The lithium battery uses a 18650 cylindrical lithium-ion secondary battery with a nominal capacity of 2900mAh and a wide temperature range of -40℃~85℃ discharge temperature. The solar panel selects 5V and the output power is about 1.1W. The charging management chip uses the CN3791 chip of Ruyun Electronics Company, which is a high-efficiency PWM buck mode converter charging chip dedicated to solar energy. It has trickle, constant current and constant voltage charging modes, which is very suitable for lithium battery charging management.

[0046] The power supply module also includes a switch interface connected to an external switch, which is set between the battery interface and the power conversion circuit. The power conversion circuit includes an LDO linear regulator and a DCDC buck-boost chip. The LDO linear regulator provides 3V power for the microcontroller, integration circuit, analog-to-digital conversion circuit, dual threshold trigger circuit and monostable circuit. The DCDC buck-boost chip provides 3.6V power for the communication module. The Roche coil does not need power supply. The external switch is designed to prevent the battery from running out during storage or transportation, and disconnect the battery from the back end when not needed.

[0047] In order to prevent the battery from running out of power, the current is small during solar charging. At this time, the device will shut down due to low power when it is turned on, and the device may not start normally. The shutdown voltage is designed to be 3V and the startup voltage is 3.4V, that is, when the battery power is lower than 3V, the communication module power is turned off, and when the battery voltage is higher than 3.4V, the communication module is turned on. To this end, the TL331 comparator is used to build a hysteresis comparator circuit, which is arranged between the switch interface and the LDO linear regulator. The reference voltage is 2.5V, which can be divided by resistors. The voltage control part is controlled by MOS tubes, and the communication module power is turned on or off according to the output of the hysteresis comparator circuit.

[0048] Here’s how it works:

[0049] After the MCU is awakened by timing or triggering, it collects and processes data, and enters sleep mode after completing data transmission. In this mode, the MCU controls the power supply of the EC800 module and the MCU enters sleep mode. In this state, the trigger circuit works normally and the collection work is carried out normally. The overall power consumption in the sleep state is designed not to exceed 5mA.

[0050] The preferred embodiments for implementing the present invention have been described in detail above, but it should be understood that the role of these embodiments is only to exemplify, and is not intended to limit the scope, applicability or configuration of the present invention in any way. The protection scope of the present invention is defined by the attached claims and their equivalents. A person of ordinary skill in the art can make many changes to the above embodiments under the guidance of the present invention, and these changes all fall within the protection scope of the present invention.

Claims

1. A power supply arm branch fault detection terminal, characterized in that: The terminal includes a Rogowski coil and a box body, wherein the Rogowski coil is installed on a cable to be tested, and the cable to be tested is located at the center of the Rogowski coil; the box body is fixedly installed on a power supply arm cable or a support, and a circuit board and a lithium battery are arranged inside the box body, and a circuit structure is arranged on the circuit board, and the circuit structure includes a main control module, a communication module, a trigger module and a power supply module, and the power supply module provides power management for the power supply arm branch fault detection terminal, and the Rogowski coil is connected to the main control module through the trigger module; the Rogowski coil detects the current of the power supply arm to be tested, and the main control module collects the detected current information and uploads the current information to the Internet of Things server through the communication module, wherein the trigger module provides timing triggering and external interrupt triggering for the main control module.

2. The power supply arm branch fault detection terminal according to claim 1, characterized in that: The model of the Rogowski coil is ZRC-50; the Rogowski coil is fixed to the outer circumference of the cable to be tested through a coil bracket.

3. The power supply arm branch fault detection terminal according to claim 1, characterized in that: The main control module adopts an STM32L151RBT6 single-chip microcomputer, and the single-chip microcomputer is connected with a status indicator light, a SWD interface, a debugging UART interface, a watchdog circuit and a battery voltage acquisition circuit.

4. The power supply arm branch fault detection terminal according to claim 3, characterized in that: The communication module uses the EC800 module, whose ports are connected with an antenna interface, a SIM card interface, a USB interface and a communication interface. The communication interface communicates with the single-chip microcomputer through a level conversion chip.

5. The power supply arm branch fault detection terminal according to claim 3, characterized in that: The trigger module includes an integration circuit, an analog-to-digital conversion circuit, a dual-threshold trigger circuit and a monostable circuit. The Rogowski coil is connected to the integration circuit through a coil interface. One output of the integration circuit is connected to the analog-to-digital conversion circuit, which is converted into an SPI signal and then processed by a single-chip microcomputer, and the other output is connected to the dual-threshold trigger circuit; the dual-threshold trigger circuit is connected to the single-chip microcomputer through the monostable circuit.

6. The power supply arm branch fault detection terminal according to claim 5, characterized in that: The integration circuit adopts an M6LP chip, the analog-to-digital conversion circuit adopts an ADS7822 chip, the dual-threshold trigger circuit adopts a TLV7032 chip, and the monostable circuit adopts an SN74LVC1G123 chip.

7. The power supply arm branch fault detection terminal according to claim 3, characterized in that: The power supply module includes a charging management chip, which is respectively connected to a charging interface, a solar charging interface and a battery interface. The charging interface is connected to an external power supply, the solar charging interface is connected to a solar panel, and the battery interface is connected to a lithium battery.

8. The power supply arm branch fault detection terminal according to claim 7, characterized in that: The power supply module also includes a switch interface connected to an external switch, the switch interface is arranged between the battery interface and the power conversion circuit, the power conversion circuit includes an LDO linear regulator and a DCDC buck-boost chip, the LDO linear regulator provides a 3V power supply for the microcontroller and the trigger module, and the DCDC buck-boost chip provides a 3.6V power supply for the communication module.

9. The power supply arm branch fault detection terminal according to claim 8, characterized in that: The power supply module further includes a hysteresis comparator circuit, which is arranged between the switch interface and the LDO linear regulator.

10. The power supply arm branch fault detection terminal according to claim 7, characterized in that: The charging management chip adopts the CN3791 chip.

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