Handset for rail-to-ground transition resistance test

Abstract

The utility model provides a handset used for a rail-ground transition resistance test, and relates to the technical field of rail electrical parameter measurement. The handset is characterized in that a first steel rail voltage measuring circuit and a second steel rail voltage measuring circuit are respectively connected to an analog-to-digital conversion module through a first signal conditioning circuit; the rail ground voltage measuring circuit is connected to the analog-to-digital conversion module through the second signal conditioning circuit; the analog-to-digital converter and the memory are respectively connected to the microcontroller; the first steel rail voltage measuring circuit is used for measuring a 10-meter voltage tiny signal of the first steel rail; the second steel rail voltage measuring circuit is used for measuring a 10-meter voltage tiny signal of a second steel rail; the analog-to-digital conversion module is used for converting the 10-meter voltage tiny signal conditioned by the first signal conditioning circuit and the rail ground voltage conditioned by the second signal conditioning circuit into digital signals; the microcontroller is used for acquiring the digital signal and storing the digital signal to the memory. The handset is high in integration level, simple in wiring, easy to carry, high in maneuverability, easy to operate and high in measured data synchronism.

Description

Technical Field

[0001] The utility model relates to the technical field of track electrical parameter measurement, in particular to a handheld device used for rail-to-ground transition resistance testing. Background Art

[0002] Currently, urban rail transit systems both domestically and internationally utilize a DC traction power supply system (hereinafter referred to as the system). Trains draw power from the overhead catenary, and the traction current returns to the negative terminal of the rectifier unit in the traction substation via the running rails, forming the return path for the traction current. DC traction power supply systems utilize suspended grounding, with the running rails insulated from the ground. Due to the inherent longitudinal resistance of the running rails, the return traction current creates a potential difference between the rails and the ground, known as the rail potential. Because the running rails are not completely insulated from the ground and the rail potential exists between the rails and the ground, some of the return current leaks from the running rails into the surrounding media, generating stray current. This stray current can cause severe electrochemical corrosion to the system itself and surrounding buried metal pipelines, compromising its safe operation. Currently, stray current has become a significant safety concern for rail transit power supply systems both domestically and internationally.

[0003] Rail-to-ground transition resistance is the primary factor determining the level of stray current in the system. Because the running rails along the entire line are seamlessly welded, the traditional volt-ampere method requires three high-precision voltmeters at each measurement endpoint to measure rail and ground voltages in different sections. This presents technical challenges such as the large number of instruments required, complex wiring, and low synchronization of measured data. Furthermore, the ease of instrument omissions, the need for manual data transcription, the high workload, and the cumbersome and inefficient communication all hinder the efficiency of the actual measurement process.

[0004] On the other hand, measurement with a high-precision voltmeter requires an external power supply, which further increases the inconvenience of the measurement process. Utility Model Content

[0005] In view of the problems existing in the above-mentioned prior art, the purpose of the present invention is to provide a handheld device for rail-to-ground transition resistance testing. The handheld device has a simple structure, is compact and convenient, and has a simple and fast testing method, which can facilitate quick and accurate testing of the transition resistance.

[0006] To achieve the above-mentioned object, the utility model provides a handheld device for rail-to-ground transition resistance testing, comprising: a first rail voltage measurement circuit, a second rail voltage measurement circuit, a rail-to-ground voltage measurement circuit, a first signal conditioning circuit, a second signal conditioning circuit, an analog-to-digital converter, a microcontroller, and a memory;

[0007] The first rail voltage measurement circuit and the second rail voltage measurement circuit are respectively connected to the analog-to-digital converter via the first signal conditioning circuit; the rail-to-ground voltage measurement circuit is connected to the analog-to-digital converter via the second signal conditioning circuit; the analog-to-digital converter and the memory are respectively connected to the microcontroller;

[0008] The first rail voltage measurement circuit is used to measure the 10-meter voltage tiny signal of the first rail; the second rail voltage measurement circuit is used to measure the 10-meter voltage tiny signal of the second rail; the rail-to-ground voltage measurement circuit is used to measure the rail-to-ground voltage; the analog-to-digital converter is used to convert the 10-meter voltage tiny signal conditioned by the first signal conditioning circuit and the rail-to-ground voltage conditioned by the second signal conditioning circuit into digital signals; the microcontroller is used to obtain the digital signal and store it in the memory.

[0009] Furthermore, it also includes: a wireless communication module;

[0010] The wireless communication module is connected to the microcontroller and is used to receive the start signal and forward it to the microcontroller;

[0011] The microcontroller is also used to start the first rail voltage measurement circuit, the second rail voltage measurement circuit and the rail-to-ground voltage measurement circuit to perform measurements according to the start signal.

[0012] Furthermore, it also includes: a power supply circuit;

[0013] The power supply circuit is connected to the microcontroller and is used to provide working power for the handheld device.

[0014] Furthermore, it also includes: a charge and discharge management circuit and at least one USB interface;

[0015] The charge and discharge management circuit is connected between the microcontroller and the power supply circuit and is used to manage the charge and discharge status of the power supply circuit;

[0016] The USB interface is connected to the charge and discharge management circuit to provide a charging interface.

[0017] Furthermore, it also includes: at least one USB interface connected to the microcontroller, for exporting digital signals.

[0018] Furthermore, it also includes: a prompt module;

[0019] The prompt module is connected to the microcontroller and is used for measuring start prompt and measuring end prompt.

[0020] Further, it also includes: a manual input module;

[0021] The manual input module is connected to the microcontroller and is used for manual input by the data entry personnel.

[0022] Furthermore, it also includes: a display screen;

[0023] The display screen is connected to the controller and is used for displaying digital signals.

[0024] It can be seen that in the technical solution provided by the present invention, the first rail voltage measurement circuit, the second rail voltage measurement circuit and the rail-to-ground voltage measurement circuit integrated in the same handheld device can replace the three independent high-precision voltmeters in the traditional volt-ampere measurement method, so that the integration of the measuring device is improved, the number of measuring instruments is reduced, and the wiring complexity is reduced; further, the improvement of the integration of the measuring device helps to reduce the workload and the probability of instrument omission and improve the measurement efficiency. The memory can reduce the error rate of data recording on the basis of improving the data entry efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a structural diagram of the traditional voltammetry method for measuring rail-to-ground transition resistance.

[0026] Figure 2 This is a structural diagram of an optional solution of the utility model.

[0027] Figure 3 This is a signal sampling circuit diagram of an optional solution in the utility model.

[0028] Figure 4 This is a circuit diagram of an analog-to-digital converter in an optional solution of the utility model.

[0029] Figure 5 This is a circuit diagram of a reference voltage source in an optional solution of the utility model.

[0030] Figure 6 This is a circuit diagram of an optional charge and discharge management circuit in the utility model.

[0031] Figure 7 This is a circuit diagram of an optional USB communication module in the utility model.

[0032] Figure 8 This is a circuit diagram of a wireless communication module of an optional solution in the present utility model.

[0033] Figure 9 This is a circuit diagram of an optional prompt module in the utility model.

[0034] Figure 10 This is a circuit diagram of a manual input module of an optional solution in the utility model.

[0035] Figure 11 This is a circuit diagram of a display screen of an optional solution in the utility model. DETAILED DESCRIPTION

[0036] Hereinafter, the technical solution proposed by the utility model will be further elaborated in combination with the accompanying drawings.

[0037] like Figure 1 As shown in the figure, in the traditional voltammetry method, when the central host injects current between the rail and the ground, a voltmeter and an ammeter are used to record the voltage and current at the injection point. A manual intercom is then used to call measurement personnel at both ends, who use two voltmeters to measure the rail voltage (a tiny signal at 10 meters) and one voltmeter to measure the voltage between the rail and the ground at the sampling point (10 meters). The data is manually observed, statistically analyzed, and then aggregated for calculation. A single measurement requires seven high-precision voltmeters. Therefore, using the traditional voltammetry method to test rail-to-ground transition resistance in different sections requires a large number of personnel. The complex measurement process, numerous instruments, and complicated wiring require high professional expertise. Even so, measurement accuracy is still limited. Furthermore, the measurement process is plagued by technical issues such as poor communication, the inability to automatically record and calculate measurement results, manual communication to synchronize measurement times, and manual recording of data and calculations, which results in a high workload and prone to errors. Furthermore, the traditional voltammetry method requires a power supply, further exacerbating these issues.

[0038] In response to the technical problems existing in the above-mentioned related technologies, an embodiment of the present application provides a handheld device for rail-to-ground resistance detection. The handheld device is based on the basic operating principle of voltage measurement and is equipped with two track voltage measurement circuits and a rail-to-ground voltage measurement circuit to sample the first rail voltage, the second rail voltage and the rail-to-ground voltage of the two rails respectively, and obtain the corresponding sampling signals in the form of analog signals. The sampling signals are conditioned into digital signals by the conditioning circuit, and the controller obtains the digital signals and stores them in the memory. It should be noted that all the above-mentioned circuits are integrated into the handheld device. Obviously, the handheld device can avoid the complexity of the measurement process and does not require too much wiring. General staff can master its use method after a simple explanation, and can complete a certain degree of automated measurement process, including sampling, signal conditioning, analog-to-digital conversion and automatic storage.

[0039] Alternatively, as Figure 2 As shown, the present application provides a structural schematic diagram of a handheld device, which may include: two measurement circuits for measuring the 10-meter rail voltage tiny signals of two rails and one measurement circuit for measuring the rail-to-ground voltage, two signal conditioning circuits, an analog-to-digital converter, a microcontroller unit (MCU) and a memory.

[0040] The tiny signal of the 10-meter rail voltage is measured, conditioned by a signal conditioning circuit, and then converted into a digital signal through an analog-to-digital converter; the rail-to-ground voltage is measured, conditioned by another signal conditioning circuit, and then converted into a digital signal through an analog-to-digital converter; the microcontroller obtains the digital signal and stores it in the memory.

[0041] In some embodiments, after the microcontroller initiates the measurement process via a control signal, the first rail voltage measurement circuit and the second rail voltage measurement circuit each sample the voltage of the two parallel rails in response to the control signal, obtaining two corresponding sampled signals in the form of analog signals. These are then conditioned by the first signal conditioning circuit to filter out high-frequency common-mode interference and other interference signals from the original analog signals. The analog signals are then converted into two corresponding digital signals via an analog-to-digital converter. Similarly, the rail-to-ground voltage is sampled by the rail-to-ground voltage measurement circuit, conditioned by the second signal conditioning circuit, and processed by the analog-to-digital converter before being converted into a digital signal. The microcontroller uses these three digital signals to obtain the voltage values of the first rail voltage, the second rail voltage, and the rail-to-ground voltage at the same sampling moment, and stores them and the digital signals in a memory.

[0042] In some embodiments, the above-mentioned conditioning circuit may include the following elements: a front-end conditioning circuit composed of a series of conductive, capacitive and resistive elements, ceramic capacitors for filtering, resistors for balancing common-mode voltage, common-mode inductors for filtering high-frequency common-mode interference, ESD protectors for preventing external electrostatic surges, and analog switches for controlling channel switching of two rail sampling signals; the above-mentioned analog-to-digital converter may be any chip or circuit structure that can perform this function, such as: a 16-bit high-precision ADC converter.

[0043] like Figure 3 As shown in the figure, G1, G2, G3, G4, L5, C34, C35, R49, R56, R50, R53, R51, and R54 constitute the front-end conditioning circuit for sampling the tiny signals of two 10-meter rails. C34 and C35 are two ceramic capacitors for filtering. R49 and R56 are two resistors to balance the common-mode voltage. L5 is a common-mode inductor for filtering high-frequency common-mode interference. ESD protector D10 is used to prevent external electrostatic surges and protect ADC devices. G1, G2 and G3, G4 are analog switches that control the channel switching of the two 10-meter rail sampling signals and are turned off when no measurement is being performed to protect the subsequent circuits and ADC.

[0044] like Figure 4 As shown, U10 is a 16-bit high-precision ADC converter (analog-to-digital converter), which communicates with the microcontroller through the SPI interface. The microcontroller controls the ADC to start sampling, configure the ADC internal gain, and obtain the ADC conversion data.

[0045] like Figure 5As shown, U11 is a high-precision reference voltage source that outputs a 2.5V standard voltage to provide a reference voltage for the ADC.

[0046] Optionally, the microcontroller includes a high-performance processor that can process digital signals according to a preset calculation formula. The calculation formula can be determined according to actual conditions based on different test purposes and requirements.

[0047] In some embodiments, the memory may be any storage device capable of storing digital signal information and calculation results, such as an SD card, internal RAM, etc.

[0048] In some embodiments, the handheld device further includes: a power supply circuit, which is connected to the microcontroller and is used to provide working power for the handheld device; further, the module can be any electronic device that can provide working power to the handheld device and can be integrated into the handheld device, such as various types of dry cells, storage batteries, etc.

[0049] Further, if Figure 6 As shown, in some embodiments, a charge-discharge management circuit is also provided between the power supply circuit and the microcontroller. Optionally, the U1 chip acts as the master controller. When a 5V power supply is input at the VIN5V point, the internal linear regulator outputs the charging voltage to BAT according to the lithium battery charging process. When the battery is not charging, the internal boost controller and the external diode D5, inductor L1, and capacitors EC2, EC3, C4, and C5 form a complete boost circuit to output 5V to supply the entire handheld system.

[0050] In some embodiments, the handset further includes a USB module connected to the microcontroller for exporting measurement data and processing results, such as digital signals. Furthermore, the module includes at least one USB port, serving as both a data export port and a handset charging port. It should be noted that the USB ports serving as the data export port and the handset charging port can be independent of each other.

[0051] like Figure 7 As shown, the USB signal is converted into a UART serial signal supported by the microcontroller through the protocol conversion chip U5, so that the host computer can communicate with the handheld device through the USB and obtain the historical records of the handheld device.

[0052] In some embodiments, the handset also includes a wireless communication module, connected to the microcontroller, configured to receive a measurement start signal from the measurement host and forward it to the microcontroller to automatically and synchronously initiate the measurement. The module can also send measurement process status information to the measurement host or receive instructions from the measurement host, such as a measurement pause, to ensure consistency in the measurement progress of the two handsets during the overall measurement process. Furthermore, the module can be any wireless communication device that can cooperate with the measurement host to automatically and synchronously initiate the measurement and control the measurement process, and can be integrated into the handset.

[0053] like Figure 8 As shown, U7 is a 433M wireless communication module, which is powered by the system 5V. Due to the high peak current of wireless communication, the power supply is connected in series with the ferrite bead L3, and the tantalum capacitor C21 and ceramic capacitors C19 and C20 are connected in parallel to enhance the power supply stability. The serial communication with the microcontroller is carried out through the TX and RX interfaces to send and receive data, and the ANT is connected to the high-gain rod antenna.

[0054] In some embodiments, the handheld device further includes: a prompt module, which is connected to the microcontroller and is used to provide measurement status prompts; further, the module can be any physical device that can provide measurement status prompts to measurement personnel by light, vibration, sound or other physical signals, and can be integrated into the inside or outside surface of the handheld device, common ones include: a flash light, a vibrator or a buzzer.

[0055] like Figure 9 As shown in the figure, if a buzzer is used as a prompt module, the resistor R10 and the MOS tube Q2 form the buzzer drive circuit, and the D4 freewheeling diode is added to protect the MOS tube. The internal timer of the microcontroller can control the IO port to output PWM waves with different duty cycles and frequencies to control the loudness and tone of the buzzer.

[0056] In some embodiments, the handheld device also includes: a manual input module, which is connected to the microcontroller and is used for the measurement personnel to manually input content; further, the module can be any human-computer interaction device that can support the measurement personnel to manually input content independently and can be integrated on the outer surface of the handheld device. Common ones include: keyboard, capacitive touch screen, resistive touch screen, etc.

[0057] like Figure 10 As shown in the figure, a keyboard is used as a manual input module. Specifically, the keyboard adopts an ADC keyboard, and a total of 8 physical keys K1-K8 are connected to resistors R9-R16 respectively. Due to the different resistance values of the resistors, when different keys are pressed and divided by R8, the KEY-ADC test point will present different voltages. After being collected by the internal high-speed ADC of the microcontroller and digitally filtered, the currently pressed key can be identified.

[0058] In some embodiments, the handheld device also includes: a display screen, which is connected to the microcontroller and is used for measuring data and automatic measurement processes; further, the display screen can be any display device that can display measurement data and automatic measurement processes and can be integrated on the outer surface of the handheld device, common ones include: CRT display screen, LCD display screen, plasma display screen, etc.

[0059] like Figure 11 As shown, the display screen can be an LCD display screen. The specific LCD display screen communicates with the microcontroller through the SPI bus. C1 and C2 are LCD display bias voltage filter capacitors. Resistors R3, R4, R5 and transistor SS8050 constitute a backlight control circuit and are controlled by the microcontroller. The microcontroller can turn off the backlight of the LCD display screen and adjust the brightness.

[0060] In some embodiments, the display screen and the manual input module can be integrated into a single module, which can support the measurement personnel to manually input content, display measurement data and automate the measurement process.

[0061] The modules involved in all the above embodiments are integrated into a handheld device, the structural diagram of which is shown in FIG. Figure 2 It should be emphasized that any of the above options does not rely on other options to work, and can be integrated into Figure 2 On the handheld device shown in the structural diagram.

[0062] In some embodiments, the handset can utilize its internal charge-discharge management circuitry to provide operating power, eliminating reliance on an external power source and enabling autonomous rail-to-ground transition resistance testing. This solution reduces the number of measuring instruments and wiring, while also simplifying the measurement process, thereby improving the maneuverability of the test equipment and the efficiency of the testing process.

[0063] In some embodiments, the handheld device can export digital signal information and calculation results via a USB port. This USB port can also be used as a charging port to charge a battery connected to the charge-discharge management circuit. This solution allows for more detailed and clear data recording and storage. Beyond the necessary measurement data and calculation results, the export mechanism enables the recording of attribute information such as the time and location of each test, facilitating subsequent data application or archiving.

[0064] In some embodiments, the handset can synchronize the start and control of the measurement process with the measurement host via a wireless communication module, eliminating the need for manual intervention. This solution is highly beneficial for automated testing with handsets, ensuring that measurements at different locations are automatically synchronized and the measurement process remains consistent. This reduces the complexity of communication and coordination during the measurement process, ensures more consistent timing of measurement data at different locations, and reduces errors in the data input during subsequent calculations, resulting in more accurate results.

[0065] In some embodiments, the handheld device can use a prompt module to notify the measurement personnel of changes in measurement status, such as measurement start, measurement data anomalies, measurement line disconnection, automatic synchronization startup failure, and measurement completion. Clearly, this module can help measurement personnel identify problems more quickly, further saving measurement time and ensuring the credibility of measurement data.

[0066] In some embodiments, the handheld device can input instructions through the manual input module, which can be used to set parameters, view historical data, start or end the measurement process, change the measurement type, etc. This module provides more functions for the handheld device type and can ensure real-time control of the measurement process by the measurement personnel.

[0067] In some embodiments, the handheld device can display the measurement data and automatic measurement process in real time through the display screen. This module makes it possible for testers to monitor the measurement process in real time, which is convenient for surveyors to use and can also verify the measurement data and calculation results in time after the test is completed.

[0068] In some embodiments, the manual input module and display screen can be integrated into the same module. In this solution, the effective area of both the manual input module and the display screen can be increased, making manual input and information viewing more convenient. If supported by the microcontroller, more or more complex commands can be input, and more data or more detailed measurement processes can be viewed simultaneously.

[0069] It can be seen that in the technical solution provided by the present invention, the first rail voltage measurement circuit, the second rail voltage measurement circuit and the rail-to-ground voltage measurement circuit integrated in the same handheld device can replace the three independent high-precision voltmeters in the traditional volt-ampere measurement method, so that the integration of the measuring device is improved, the number of measuring instruments is reduced, and the wiring complexity is reduced; further, the improvement of the integration of the measuring device helps to reduce the workload and the probability of instrument omission and improve the measurement efficiency. The memory can reduce the error rate of data recording on the basis of improving the data entry efficiency.

[0070] In the above-mentioned preferred schemes, the handheld device has achieved the following beneficial effects on the basis of achieving the aforementioned beneficial effects: the wireless communication module can ensure the synchronous start-up of the measurement process of the two measurement endpoints and the synchronization of the measured data; the power supply circuit can further integrate the measuring instrument, which helps to improve the measurement efficiency and helps to improve the maneuverability and safety of the handheld device; the USB interface supports data export, which is conducive to data aggregation and archiving; the prompt module helps to improve measurement efficiency; the manual input module and display screen can improve the convenience of viewing measurement data.

[0071] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A handheld device for rail-to-ground transition resistance testing, characterized in that: include: A first rail voltage measurement circuit, a second rail voltage measurement circuit, a rail-to-ground voltage measurement circuit, a first signal conditioning circuit, a second signal conditioning circuit, an analog-to-digital converter, a microcontroller, and a memory; The first rail voltage measurement circuit and the second rail voltage measurement circuit are respectively connected to the analog-to-digital converter via the first signal conditioning circuit; the rail-to-ground voltage measurement circuit is connected to the analog-to-digital converter via the second signal conditioning circuit; The analog-to-digital converter and memory are connected to the microcontroller respectively; The first rail voltage measurement circuit is used to measure the 10-meter voltage tiny signal of the first rail; the second rail voltage measurement circuit is used to measure the 10-meter voltage tiny signal of the second rail; the rail-to-ground voltage measurement circuit is used to measure the rail-to-ground voltage; the analog-to-digital converter is used to convert the 10-meter voltage tiny signal conditioned by the first signal conditioning circuit and the rail-to-ground voltage conditioned by the second signal conditioning circuit into digital signals; the microcontroller is used to obtain the digital signal and store it in the memory.

2. The handheld device for rail-to-ground transition resistance testing according to claim 1, characterized in that: Also includes: Wireless communication module; The wireless communication module is connected to the microcontroller and is used to receive the start signal and forward it to the microcontroller; The microcontroller is also used to start the first rail voltage measurement circuit, the second rail voltage measurement circuit and the rail-to-ground voltage measurement circuit to perform measurements according to the start signal.

3. The handheld device for rail-to-ground transition resistance testing according to claim 1, characterized in that: Also includes: Power supply circuit; The power supply circuit is connected to the microcontroller and is used to provide working power for the handheld device.

4. The handheld device for rail-to-ground transition resistance testing according to claim 3, characterized in that: Also includes: Charge and discharge management circuit and at least one USB interface; The charge and discharge management circuit is connected between the microcontroller and the power supply circuit and is used to manage the charge and discharge status of the power supply circuit; The USB interface is connected to the charge and discharge management circuit to provide a charging interface.

5. The handheld device for rail-to-ground transition resistance testing according to claim 1, characterized in that: Also includes: At least one USB interface connected to the microcontroller for exporting digital signals.

6. The handheld device for rail-to-ground transition resistance testing according to claim 1, characterized in that: Also includes: Prompt module; The prompt module is connected to the microcontroller and is used for measuring start prompt and measuring end prompt.

7. The handheld device for rail-to-ground transition resistance testing according to claim 1, characterized in that: Also includes: Manual input module; The manual input module is connected to the microcontroller and is used for manual input by the data entry personnel.

8. The handheld device for rail-to-ground transition resistance testing according to claim 1, characterized in that: Also includes: Display screen; The display is connected to the microcontroller for displaying digital signals.

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