A track circuit operating characteristic analysis system and method

Abstract

This invention relates to the field of rail transit safety monitoring technology, specifically to a track circuit operating characteristic analysis system and method, comprising: a traction rail return current monitoring module, used to monitor the line parameters on the lead wire between the choke transformer and the rail, and extract its 50Hz component; and a dynamic shunt resistance monitoring module. In use, this invention, by real-time monitoring of the absolute value and direction of the rail return current, utilizes a mathematical model of the track transmission line to achieve real-time quantitative monitoring of the train shunt status, and achieves continuous spectrum tracking of the target frequency point through sliding Fourier transform, thus simultaneously monitoring traction rail return current, dynamic shunt resistance, and adjacent line interference online. Based on the monitoring data, comprehensive analysis is performed, which helps improve the sensitivity of abnormal shunt behavior detection, eliminate the influence of adjacent line interference, and requires only one current transformer to achieve multi-frequency signal extraction, thus reducing hardware complexity and cost.

Description

Technical Field

[0001] This invention relates to the field of rail transit safety monitoring technology, specifically to a system and method for analyzing the operating characteristics of track circuits. Background Technology

[0002] In railway signaling, a track circuit is a system consisting of transmitting equipment, rail lines, and receiving equipment. It is used to detect whether a section of rail line (hereinafter referred to as "track section") is occupied by a train, and when necessary, to provide locomotive signal information.

[0003] In existing technology, during actual operation, track circuits are easily affected by factors such as traction return current, interference from adjacent tracks, and contact resistance between wheelsets and rails, causing changes in the operating characteristics of the track circuits and affecting train operation. When the track circuit is operating in the adjustment state, the traction return current flowing through the rails, i.e., rail return current, becomes unbalanced, including steady-state imbalance and impact imbalance. This causes magnetic saturation of the choke transformer in the track circuit, and the track circuit switches from the adjustment state to the shunt state, i.e., the "abnormal red light band." Subsequent trains are prohibited from entering this track section, but in reality, there are no trains in this track section, which seriously affects the normal operation of trains. When the track section is occupied by a train, i.e., it should be operating in the shunt state, at which point subsequent trains should be prohibited from entering. In this section, due to localized rust on the rail surface, the contact resistance between the wheelset and the rail surface increases, weakening the short-circuit effect of the signal transmission equipment of the train's wheelset rail circuit. This leads to increased received voltage, and the track circuit relays may suddenly activate, switching to adjustment mode, affecting the normal operation of the signal system and consequently train operating efficiency. In severe cases, this can cause subsequent trains to "rush" into the track section already occupied by a train, resulting in serious accidents. When a track section needs to provide locomotive signal information to trains, if an adjacent track section is also providing locomotive signal information, trains in this track section may mistakenly interpret the locomotive signal information from the adjacent section as coming from their own, resulting in adjacent track interference. This phenomenon occurs frequently in railway operations and can easily lead to incorrect train operation and serious accidents. In summary, most current track circuits lack the ability to simultaneously monitor traction rail return current, dynamic shunt resistance, and adjacent track interference online, and to perform comprehensive analysis based on the monitoring data.

[0004] In conclusion, developing a system and method for analyzing the operating characteristics of track circuits remains a critical issue that urgently needs to be addressed in the field of rail transit safety monitoring technology. Summary of the Invention

[0005] The purpose of this invention is to solve the problem that most existing track circuits do not have the ability to simultaneously monitor traction rail return current, dynamic shunt resistance, and adjacent line interference online, and to perform comprehensive analysis based on the monitoring data. This invention provides a track circuit operating characteristic analysis system and method.

[0006] To achieve the above objectives, the present invention provides the following technical solution: This invention provides a system for analyzing the operating characteristics of track circuits, comprising: The traction rail return current monitoring module is used to monitor the line parameters on the lead wire between the choke transformer and the rail and extract its 50Hz component. The dynamic shunt resistance monitoring module establishes a mathematical model of the transmission loop based on the line parameters, calculates the shunt resistance-time curve in real time, and obtains the dynamic shunt resistance. The adjacent line interference monitoring module is used to extract the locomotive signal information current frequency component from the line parameters and monitor adjacent line interference. The frequency signal extraction module is used to output frequency domain signals through the MCU using digital filtering and fast Fourier transform algorithms, and to calculate the corresponding signal current value according to the frequency points of different signals.

[0007] Furthermore, the traction rail return current monitoring module is used to monitor the line parameters on the lead wire between the choke transformer and the rail, and its workflow for extracting the 50Hz component is as follows: By installing choke transformers on both sides of the insulation joint and connecting the center points of the two choke transformers with a center connecting plate, the rail return current path is connected. Then, the current on the lead wire between the choke transformer and the rail is monitored, the 50Hz component is extracted, the rail return current is monitored, and the unbalanced rail return current is calculated.

[0008] Furthermore, the dynamic shunt resistance monitoring module, based on the line parameters, establishes a mathematical model of the transmission loop and calculates the shunt resistance-time curve in real time, thus obtaining the following workflow for the dynamic shunt resistance: The line parameters include, but are not limited to, uniform transmission line theory, track section length, and ballast type. A mathematical model of the transmission loop is established. The track signal voltage and current at a frequency of 25Hz from the transmitting side rail lead-in line are used as outputs, and the track signal voltage and current from the receiving side rail lead-in line are used as inputs. The equivalent shunt resistance of the train is calculated in real time, thereby generating shunt resistance-time curve data to obtain the dynamic shunt resistance, expressed as: In the formula, Indicates time Reflection coefficient at time 10:00 Indicates time The equivalent shunt resistance at time . It represents the intrinsic impedance of the track circuit, and based on the historical curve data of the dynamic shunt resistor, it tracks the operating characteristics of the shunt state of one section, providing a maintenance basis for on-site maintenance personnel.

[0009] Furthermore, the adjacent line interference monitoring module is used to extract the locomotive signal information current frequency component from the line parameters. The workflow for monitoring adjacent line interference is as follows: When a train enters an adjacent track section and that section requires locomotive signal information, it constitutes an interference source. The locomotive signal information creates interference in the signal transmission loop of this track section through paths including but not limited to spatial coupling and ground conduction. By monitoring the current on the rail leads of the choke transformer, the frequency components of the locomotive signal information are extracted, including four frequency points: 1700Hz, 2000Hz, 2300Hz, and 2600Hz. An observation window is then constructed. For time series signals Perform a sliding Fourier transform, the expression is: In the formula, Indicates time Time to frequency The time-frequency energy spectral density value at that location, Indicates the length of the time window Integrating the signal from within arrive , Indicates time The time function of the original signal being observed. It is a window function. Indicates center alignment at Symmetrical windows, The complex exponential function is used to extract frequency. The signal components, It is the imaginary unit. Indicates the first The frequency value of each frequency component This represents the current time point in the scan. Represents the time variable Integrate the points.

[0010] Furthermore, the adjacent line interference monitoring module is used to extract the locomotive signal information current frequency component from the line parameters. The workflow for monitoring adjacent line interference is as follows: When a locomotive signal information frequency point from an adjacent track section is detected on the choke transformer lead wire of this track section, it indicates the presence of adjacent line interference. When the current of the adjacent line interference exceeds a preset value, on-site maintenance personnel resolve the adjacent line interference by lowering the output voltage of the locomotive signal information power supply in the adjacent section. The expression is: In the formula, This indicates the output voltage after the interference occurred. This represents the signal source voltage when there is no interference. It is a regulating factor used to control the sensitivity of voltage regulation. Indicates time The instantaneous value of the adjacent line interference current at time . This indicates the minimum disturbance value at which intervention and adjustment are needed. This represents the current value at which the interference reaches a critical threshold. This indicates the current disturbance as a linear proportion of the alarm and critical threshold.

[0011] Furthermore, the frequency signal extraction module, which uses the MCU to output frequency domain signals through digital filtering and fast Fourier transform algorithms, and calculates the corresponding signal current values ​​based on the frequency points of different signals, works as follows: Using a single current transformer, the analog current is converted into a signal that can be processed by an MCU microcontroller based on an ADC analog-to-digital converter. The MCU then employs a digital filtering algorithm to filter out components other than track circuit current, traction rail return current, and locomotive signal information frequencies. The expression is: In the formula, Indicates the first The filtered signal value at each time point. Is seeking The sum of, It is an index variable The range is from 0 to common item, Indicates the filter for the first The weight value of each delayed input, It is the first in the original input signal The value of each sampling point represents the current time step back. The value of the step.

[0012] Furthermore, the frequency signal extraction module, which uses the MCU to output frequency domain signals through digital filtering and fast Fourier transform algorithms, and calculates the corresponding signal current values ​​based on the frequency points of different signals, works as follows: The Fast Fourier Transform algorithm converts the filtered time-domain signal into a frequency-domain signal for output, expressed as: In the formula, Indicates the first Complex frequency domain output at each frequency point Indicates to arrive Accumulate. It is an index variable The range is from 0 to common item, Indicates the first Filtered current signal values ​​at each time-domain sampling point The rotation factor is used to project a time-domain signal onto the frequency domain. The base of the natural logarithm, It is the imaginary unit. To represent the angle of a complete sine wave, The frequency point index ranges from 0 to... , This represents the total number of sampling points in the Fast Fourier Transform. A spectral reconstruction factor is added based on the frequency of different signals to calculate the corresponding signal current value. The expression is: In the formula, Indicates the first Estimated current amplitude at each frequency point The first one defined Spectral leakage compensation factor at each frequency point This indicates the turns ratio of the current transformer. This represents the voltage-to-digital gain conversion factor of the ADC analog-to-digital converter. Indicates the first Window function weights for each point The cosine function is used to describe the response of a window function under frequency shift conditions. It is the Fast Fourier Transform (FFT) The center frequency of each frequency point Represents the actual frequency components in the actual signal. Indicates the sampling period.

[0013] On the other hand, the present invention also provides a method for analyzing the operating characteristics of a track circuit, which includes the following steps: S1. By monitoring the line parameters on the lead wire between the choke transformer and the rail, the 50Hz component is extracted. S2. Based on the line parameters, establish a mathematical model of the transmission loop, calculate the shunt resistance-time curve in real time, and obtain the dynamic shunt resistance. S3. Extract the locomotive signal information current frequency component from the line parameters and monitor adjacent line interference; S4. The MCU uses digital filtering and fast Fourier transform algorithms to output frequency domain signals and calculates the corresponding signal current values ​​based on the frequency points of different signals.

[0014] Furthermore, in step S1, the method for extracting the 50Hz component by monitoring the line parameters on the lead wire between the choke transformer and the rail is as follows: By installing choke transformers on both sides of the insulation joint and connecting the center points of the two choke transformers with a center connecting plate, the rail return current path is connected. Then, the current on the lead wire between the choke transformer and the rail is monitored, the 50Hz component is extracted, the rail return current is monitored, and the unbalanced rail return current is calculated.

[0015] Further, in step S2, based on the line parameters, a mathematical model of the transmission loop is established, and the curve of shunt resistance versus time is calculated in real time to obtain the dynamic shunt resistance. The line parameters include, but are not limited to, uniform transmission line theory, track section length, and ballast type. A mathematical model of the transmission loop is established. The track signal voltage and current at a frequency of 25Hz from the transmitting side rail lead-in line are used as outputs, and the track signal voltage and current from the receiving side rail lead-in line are used as inputs. The equivalent shunt resistance of the train is calculated in real time, thereby generating shunt resistance-time curve data to obtain the dynamic shunt resistance, expressed as: In the formula, Indicates time Reflection coefficient at time 10:00 Indicates time The equivalent shunt resistance at time . It represents the intrinsic impedance of the track circuit, and based on the historical curve data of the dynamic shunt resistor, it tracks the operating characteristics of the shunt state of one section, providing a maintenance basis for on-site maintenance personnel.

[0016] Further, in step S3, the method for extracting the locomotive signal information current frequency component from the line parameters and monitoring adjacent line interference is as follows: When a train enters an adjacent track section and that section requires locomotive signal information, it constitutes an interference source. The locomotive signal information creates interference in the signal transmission loop of this track section through paths including but not limited to spatial coupling and ground conduction. By monitoring the current on the rail leads of the choke transformer, the frequency components of the locomotive signal information are extracted, including four frequency points: 1700Hz, 2000Hz, 2300Hz, and 2600Hz. An observation window is then constructed. For time series signals Perform a sliding Fourier transform, the expression is: In the formula, Indicates time Time to frequency The time-frequency energy spectral density value at that location, Indicates the length of the time window Integrating the signal from within arrive , Indicates time The time function of the original signal being observed. It is a window function. Indicates center alignment at Symmetrical windows, The complex exponential function is used to extract frequency. The signal components, It is the imaginary unit. Indicates the first The frequency value of each frequency component This represents the current time point in the scan. Represents the time variable Integrate the points.

[0017] When a locomotive signal information frequency point from an adjacent track section is detected on the choke transformer lead wire of this track section, it indicates the presence of adjacent line interference. When the current of the adjacent line interference exceeds a preset value, on-site maintenance personnel resolve the adjacent line interference by lowering the output voltage of the locomotive signal information power supply in the adjacent section. The expression is: In the formula, This indicates the output voltage after the interference occurred. This represents the signal source voltage when there is no interference. It is a regulating factor used to control the sensitivity of voltage regulation. Indicates time The instantaneous value of the adjacent line interference current at time . This indicates the minimum disturbance value at which intervention and adjustment are needed. This represents the current value at which the interference reaches a critical threshold. This indicates the current disturbance as a linear proportion of the alarm and critical threshold.

[0018] Furthermore, in step S4, the method for the MCU to output the frequency domain signal using a digital filtering algorithm and a fast Fourier transform algorithm, and to calculate the corresponding signal current value based on the frequency points of different signals, is as follows: Using a single current transformer, the analog current is converted into a signal that can be processed by an MCU microcontroller based on an ADC analog-to-digital converter. The MCU then employs a digital filtering algorithm to filter out components other than track circuit current, traction rail return current, and locomotive signal information frequencies. The expression is: In the formula, Indicates the first The filtered signal value at each time point. Is seeking The sum of, It is an index variable The range is from 0 to common item, Indicates the filter for the first The weight value of each delayed input, It is the first in the original input signal The value of each sampling point represents the current time step back. The value of the step.

[0019] The Fast Fourier Transform algorithm converts the filtered time-domain signal into a frequency-domain signal for output, expressed as: In the formula, Indicates the first Complex frequency domain output at each frequency point Indicates to arrive Accumulate. It is an index variable The range is from 0 to common item, Indicates the first Filtered current signal values ​​at each time-domain sampling point The rotation factor is used to project a time-domain signal onto the frequency domain. The base of the natural logarithm, It is the imaginary unit. To represent the angle of a complete sine wave, The frequency point index ranges from 0 to... , This represents the total number of sampling points in the Fast Fourier Transform. A spectral reconstruction factor is added based on the frequency of different signals to calculate the corresponding signal current value. The expression is: In the formula, Indicates the first Estimated current amplitude at each frequency point The first one defined Spectral leakage compensation factor at each frequency point This indicates the turns ratio of the current transformer. This represents the voltage-to-digital gain conversion factor of the ADC analog-to-digital converter. Indicates the first Window function weights for each point The cosine function is used to describe the response of a window function under frequency shift conditions. It is the Fast Fourier Transform (FFT) The center frequency of each frequency point Represents the actual frequency components in the actual signal. Indicates the sampling period.

[0020] Beneficial effects Compared with known public technologies, the technical solution provided by this invention has the following beneficial effects: In use, this invention achieves real-time quantitative monitoring of train shunt status by monitoring the absolute value and direction of the rail return current in real time and utilizing a mathematical model of the track transmission line. It also achieves continuous spectrum tracking of the target frequency point through sliding Fourier transform, enabling simultaneous online monitoring of traction rail return current, dynamic shunt resistance, and adjacent line interference. Based on the monitoring data, comprehensive analysis is performed, which helps improve the sensitivity of abnormal shunt behavior detection and eliminate the influence of adjacent line interference. At the same time, only one current transformer is needed to extract signals from multiple frequency points, which helps reduce hardware complexity and cost. Attached Figure Description

[0021] Figure 1 This is a system diagram of a track circuit operating characteristic analysis system according to the present invention; Figure 2 This is a flowchart of a method for analyzing the operating characteristics of a track circuit according to the present invention; Figure 3 This is a schematic diagram of the rail return current crossing mechanical insulation joint of a track circuit operating characteristic analysis system according to the present invention; Figure 4 This is a schematic diagram of the dynamic shunt resistor principle of a track circuit operating characteristic analysis system according to the present invention; Figure 5 This is a schematic diagram of the device structure for the method of analyzing the working characteristics of a track circuit according to the present invention. Detailed Implementation

[0022] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0023] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0024] The present invention will now be described in further detail with reference to the accompanying drawings: Example 1: like Figure 1 - Figure 5 As shown, the present invention provides a track circuit operating characteristic analysis system, comprising: The traction rail return current monitoring module is used to monitor the line parameters on the lead wire between the choke transformer and the rail and extract its 50Hz component. Furthermore, the traction rail return current monitoring module is used to monitor the line parameters on the lead wire between the choke transformer and the rail, and its workflow for extracting the 50Hz component is as follows: By installing choke transformers on both sides of the insulation joint and connecting the center points of the two choke transformers with a center connecting plate, the rail return current path is connected. Then, the current on the lead wire between the choke transformer and the rail is monitored, the 50Hz component is extracted, the rail return current is monitored, and the unbalanced rail return current is calculated. Specifically, the current returning to the rails flows in the same direction on both rails, as indicated. Figure 3By extracting the components of the 50Hz traction current, the absolute value and direction of the rail return current can be monitored in real time. The rail return current imbalance index can quantitatively describe the current deviation, improving the intelligence level of equipment health assessment. When a significant imbalance occurs, the system can automatically issue an alarm, indicating that there may be problems such as loose contact of the choke transformer lead wire or cable fault.

[0025] The dynamic shunt resistance monitoring module establishes a mathematical model of the transmission loop based on the line parameters, calculates the shunt resistance-time curve in real time, and obtains the dynamic shunt resistance. Furthermore, the dynamic shunt resistance monitoring module, based on the line parameters, establishes a mathematical model of the transmission loop and calculates the shunt resistance-time curve in real time, thus obtaining the following workflow for the dynamic shunt resistance: The line parameters include, but are not limited to, uniform transmission line theory, track section length, and ballast type. A mathematical model of the transmission loop is established. The track signal voltage and current at a frequency of 25Hz from the transmitting side rail lead-in line are used as outputs, and the track signal voltage and current from the receiving side rail lead-in line are used as inputs. The equivalent shunt resistance of the train is calculated in real time, thereby generating shunt resistance-time curve data to obtain the dynamic shunt resistance, expressed as: In the formula, Indicates time Reflection coefficient at time 10:00 Indicates time The equivalent shunt resistance at time . It represents the intrinsic impedance of the track circuit, and based on the historical curve data of the dynamic shunt resistor, it tracks the operating characteristics of the shunt state of one section, providing a maintenance basis for on-site maintenance personnel.

[0026] Specifically, dynamic shunt resistance refers to the equivalent resistance of the train's wheelsets (which may be multiple wheelsets) to the shunt resistance of the track section during train travel. (See diagram for principle.) Figure 4 The dynamic shunt resistance monitoring module establishes a mathematical model of the track transmission line to achieve real-time quantitative monitoring of the train shunt status. By no longer relying on the traditional binary judgment of voltage / no voltage, it improves the sensitivity of detecting abnormal shunt behavior (such as loose connections and interruptions). Through the continuous change trend of the reflection coefficient, it can predict fault signs such as poor contact and cable aging in advance. It provides maintenance personnel with a visual basis using historical shunt impedance data, which helps to formulate differentiated and preventive operation and maintenance plans.

[0027] The adjacent line interference monitoring module is used to extract the locomotive signal information current frequency component from the line parameters and monitor adjacent line interference. Furthermore, the adjacent line interference monitoring module is used to extract the locomotive signal information current frequency component from the line parameters. The workflow for monitoring adjacent line interference is as follows: When a train enters an adjacent track section and that section requires locomotive signal information, it constitutes an interference source. The locomotive signal information creates interference in the signal transmission loop of this track section through paths including but not limited to spatial coupling and ground conduction. By monitoring the current on the rail leads of the choke transformer, the frequency components of the locomotive signal information are extracted, including four frequency points: 1700Hz, 2000Hz, 2300Hz, and 2600Hz. An observation window is then constructed. For time series signals Perform a sliding Fourier transform, the expression is: In the formula, Indicates time Time to frequency The time-frequency energy spectral density value at that location, Indicates the length of the time window Integrating the signal from within arrive , Indicates time The time function of the original signal being observed. It is a window function. Indicates center alignment at Symmetrical windows, The complex exponential function is used to extract frequency. The signal components, It is the imaginary unit. Indicates the first The frequency value of each frequency component This represents the current time point in the scan. Represents the time variable Integrate the points.

[0028] Furthermore, the adjacent line interference monitoring module is used to extract the locomotive signal information current frequency component from the line parameters. The workflow for monitoring adjacent line interference is as follows: When a locomotive signal information frequency point from an adjacent track section is detected on the choke transformer lead wire of this track section, it indicates the presence of adjacent line interference. When the current of the adjacent line interference exceeds a preset value, on-site maintenance personnel resolve the adjacent line interference by lowering the output voltage of the locomotive signal information power supply in the adjacent section. The expression is: In the formula, This indicates the output voltage after the interference occurred. This represents the signal source voltage when there is no interference. It is a regulating factor used to control the sensitivity of voltage regulation. Indicates time The instantaneous value of the adjacent line interference current at time . This indicates the minimum disturbance value at which intervention and adjustment are needed. This represents the current value at which the interference reaches a critical threshold. This indicates the current disturbance as a linear proportion of the alarm and critical threshold.

[0029] Specifically, the adjacent line interference monitoring module uses time-frequency analysis technology to accurately identify and adaptively control adjacent line interference in track circuits. Taking a double-track section of the Beijing-Shanghai High-Speed ​​Railway as an example, when a train enters an adjacent track section and sends a 2000Hz locomotive signal, spatial electromagnetic coupling will generate an induced current of about 50mA on the lead wire of the choke transformer in this section (normal background noise <10mA). By constructing a 500ms observation window through the Hamming window function, a sliding Fourier transform is performed on the lead wire current, separating four characteristic frequency points from 1700Hz to 2600Hz in the time-frequency domain. When the energy spectral density of the 2000Hz frequency point continuously exceeds 0.8V² / Hz (preset alarm threshold), it is determined that adjacent line interference exists, and the interference current is calculated to be 62mA (exceeding the preset value of 50mA). At this time, according to the ratio of the interference current to the critical threshold (100mA) (currently 0.62), the voltage of the signal source in the adjacent section is dynamically adjusted by setting an adjustment factor. =0.3, reducing the output voltage from the standard 120V to 113V (120×(1-0.3×0.62)), reducing the interference current to 45mA, and eliminating the interference effect.

[0030] The frequency signal extraction module is used to output frequency domain signals through the MCU using digital filtering and fast Fourier transform algorithms, and to calculate the corresponding signal current value according to the frequency points of different signals. Furthermore, the frequency signal extraction module, which uses the MCU to output frequency domain signals through digital filtering and fast Fourier transform algorithms, and calculates the corresponding signal current values ​​based on the frequency points of different signals, works as follows: Using a single current transformer, the analog current is converted into a signal that can be processed by an MCU microcontroller based on an ADC analog-to-digital converter. The MCU then employs a digital filtering algorithm to filter out components other than track circuit current, traction rail return current, and locomotive signal information frequencies. The expression is: In the formula, Indicates the first The filtered signal value at each time point. Is seeking The sum of, It is an index variable The range is from 0 to common item, Indicates the filter for the first The weight value of each delayed input, It is the first in the original input signal The value of each sampling point represents the current time step back. The value of the step.

[0031] Furthermore, the frequency signal extraction module, which uses the MCU to output frequency domain signals through digital filtering and fast Fourier transform algorithms, and calculates the corresponding signal current values ​​based on the frequency points of different signals, works as follows: The Fast Fourier Transform algorithm converts the filtered time-domain signal into a frequency-domain signal for output, expressed as: In the formula, Indicates the first Complex frequency domain output at each frequency point Indicates to arrive Accumulate. It is an index variable The range is from 0 to common item, Indicates the first Filtered current signal values ​​at each time-domain sampling point The rotation factor is used to project a time-domain signal onto the frequency domain. The base of the natural logarithm, It is the imaginary unit. To represent the angle of a complete sine wave, The frequency point index ranges from 0 to... , This represents the total number of sampling points in the Fast Fourier Transform. A spectral reconstruction factor is added based on the frequency of different signals to calculate the corresponding signal current value. The expression is: In the formula, Indicates the first Estimated current amplitude at each frequency point The first one defined Spectral leakage compensation factor at each frequency point This indicates the turns ratio of the current transformer. This represents the voltage-to-digital gain conversion factor of the ADC analog-to-digital converter. Indicates the first Window function weights for each point The cosine function is used to describe the response of a window function under frequency shift conditions. It is the Fast Fourier Transform (FFT) The center frequency of each frequency point Represents the actual frequency components in the actual signal. Indicates the sampling period.

[0032] Specifically, the track current signal is acquired by a single current transformer. The analog signal is converted into a digital signal by an ADC and then input to an MCU microcontroller for processing. Interference signals other than the target frequency are removed by a digital filter. The time-domain signal is then transformed into a frequency-domain signal by a fast Fourier transform. The spectrum signal is further reconstructed and the amplitude is estimated, which makes it easy to accurately distinguish weak current signals at multiple frequency points. Even in complex interference environments, specific frequency points can be accurately identified. Only one current transformer is needed to extract signals at multiple frequency points, reducing hardware complexity and cost.

[0033] Example 2: like Figure 1 - Figure 5 As shown, Example 2 provides a method for analyzing the operating characteristics of a track circuit, which includes the following steps: S1. By monitoring the line parameters on the lead wire between the choke transformer and the rail, the 50Hz component is extracted. S2. Based on the line parameters, establish a mathematical model of the transmission loop, calculate the shunt resistance-time curve in real time, and obtain the dynamic shunt resistance. S3. Extract the locomotive signal information current frequency component from the line parameters and monitor adjacent line interference; S4. The MCU uses digital filtering and fast Fourier transform algorithms to output frequency domain signals and calculates the corresponding signal current values ​​based on the frequency points of different signals.

[0034] Furthermore, in step S1, the method for extracting the 50Hz component by monitoring the line parameters on the lead wire between the choke transformer and the rail is as follows: By installing choke transformers on both sides of the insulation joint and connecting the center points of the two choke transformers with a center connecting plate, the rail return current path is connected. Then, the current on the lead wire between the choke transformer and the rail is monitored, the 50Hz component is extracted, the rail return current is monitored, and the unbalanced rail return current is calculated.

[0035] Further, in step S2, based on the line parameters, a mathematical model of the transmission loop is established, and the curve of shunt resistance versus time is calculated in real time to obtain the dynamic shunt resistance. The line parameters include, but are not limited to, uniform transmission line theory, track section length, and ballast type. A mathematical model of the transmission loop is established. The track signal voltage and current at a frequency of 25Hz from the transmitting side rail lead-in line are used as outputs, and the track signal voltage and current from the receiving side rail lead-in line are used as inputs. The equivalent shunt resistance of the train is calculated in real time, thereby generating shunt resistance-time curve data to obtain the dynamic shunt resistance, expressed as: In the formula, Indicates time Reflection coefficient at time 10:00 Indicates time The equivalent shunt resistance at time . It represents the intrinsic impedance of the track circuit, and based on the historical curve data of the dynamic shunt resistor, it tracks the operating characteristics of the shunt state of one section, providing a maintenance basis for on-site maintenance personnel.

[0036] Further, in step S3, the method for extracting the locomotive signal information current frequency component from the line parameters and monitoring adjacent line interference is as follows: When a train enters an adjacent track section and that section requires locomotive signal information, it constitutes an interference source. The locomotive signal information creates interference in the signal transmission loop of this track section through paths including but not limited to spatial coupling and ground conduction. By monitoring the current on the rail leads of the choke transformer, the frequency components of the locomotive signal information are extracted, including four frequency points: 1700Hz, 2000Hz, 2300Hz, and 2600Hz. An observation window is then constructed. For time series signals Perform a sliding Fourier transform, the expression is: In the formula, Indicates time Time to frequency The time-frequency energy spectral density value at that location, Indicates the length of the time window Integrating the signal from within arrive , Indicates time The time function of the original signal being observed. It is a window function. Indicates center alignment at Symmetrical windows, The complex exponential function is used to extract frequency. The signal components, It is the imaginary unit. Indicates the first The frequency value of each frequency component This represents the current time point in the scan. Represents the time variable Integrate the points.

[0037] When a locomotive signal information frequency point from an adjacent track section is detected on the choke transformer lead wire of this track section, it indicates the presence of adjacent line interference. When the current of the adjacent line interference exceeds a preset value, on-site maintenance personnel resolve the adjacent line interference by lowering the output voltage of the locomotive signal information power supply in the adjacent section. The expression is: In the formula, This indicates the output voltage after the interference occurred. This represents the signal source voltage when there is no interference. It is a regulating factor used to control the sensitivity of voltage regulation. Indicates time The instantaneous value of the adjacent line interference current at time . This indicates the minimum disturbance value at which intervention and adjustment are needed. This represents the current value at which the interference reaches a critical threshold. This indicates the current disturbance as a linear proportion of the alarm and critical threshold.

[0038] Furthermore, in step S4, the method for the MCU to output the frequency domain signal using a digital filtering algorithm and a fast Fourier transform algorithm, and to calculate the corresponding signal current value based on the frequency points of different signals, is as follows: Using a single current transformer, the analog current is converted into a signal that can be processed by an MCU microcontroller based on an ADC analog-to-digital converter. The MCU then employs a digital filtering algorithm to filter out components other than track circuit current, traction rail return current, and locomotive signal information frequencies. The expression is: In the formula, Indicates the first The filtered signal value at each time point. Is seeking The sum of, It is an index variable The range is from 0 to common item, Indicates the filter for the first The weight value of each delayed input, It is the first in the original input signal The value of each sampling point represents the current time step back. The value of the step.

[0039] The Fast Fourier Transform algorithm converts the filtered time-domain signal into a frequency-domain signal for output, expressed as: In the formula, Indicates the first Complex frequency domain output at each frequency point Indicates to arrive Accumulate. It is an index variable The range is from 0 to common item, Indicates the first Filtered current signal values ​​at each time-domain sampling point The rotation factor is used to project a time-domain signal onto the frequency domain. The base of the natural logarithm, It is the imaginary unit. To represent the angle of a complete sine wave, The frequency point index ranges from 0 to... , This represents the total number of sampling points in the Fast Fourier Transform. A spectral reconstruction factor is added based on the frequency of different signals to calculate the corresponding signal current value. The expression is: In the formula, Indicates the first Estimated current amplitude at each frequency point The first one is defined Spectral leakage compensation factor at each frequency point This indicates the turns ratio of the current transformer. This represents the voltage-to-digital gain conversion factor of the ADC analog-to-digital converter. Indicates the first Window function weights for each point The cosine function is used to describe the response of a window function under frequency shift conditions. It is the Fast Fourier Transform (FFT) The center frequency of each frequency point Represents the actual frequency components in the actual signal. Indicates the sampling period.

[0040] Specifically, the device test structure consists of a test unit, a handheld terminal, and a PC terminal, as shown in the diagram. Figure 4The testing unit is primarily responsible for acquiring voltage and current data, extracting different frequency components, and sharing the monitoring results with handheld terminals and PCs via Bluetooth or SD card transfer. The handheld terminal is a portable operating terminal, designed to support the testing unit and provide simple data query and analysis. Its main functions include reading the testing unit's time, synchronizing the testing unit's time, checking the remaining battery power, setting the testing unit's operating mode, viewing the testing unit's monitoring data online, and recording test data. The PC is responsible for data processing and analysis. The PC collects all acquired data, supports direct import from the acquisition device, and data upload from the tablet. It also handles the processing, management, and querying of data related to traction rail return current, dynamic shunt resistance, and adjacent line interference, providing a historical curve query function.

[0041] Specifically, the operational steps and strategies for staff are as follows: A. Retrieve the traction rail return current and its imbalance value at the time point of the abnormal red light band in the track section, send the measured voltage and current, receive the voltage and current on the receiving side, analyze the correlation between different monitoring data at the same time, and locate the cause of the fault.

[0042] B. Retrieve dynamic shunt resistance curves for different trains, at different times, and under different climatic conditions in the track section, analyze the correlation between the working characteristics of the shunt state in the same track section and the train, time, and climatic environment, and assist in the maintenance of track circuits on site.

[0043] C. Intelligently monitors the interference frequency current of adjacent lines on the rail lead-in lines of the track section and determines in real time whether the current exceeds the set threshold. If the set threshold is exceeded, an early warning is triggered, and possible interference source sections are provided.

[0044] D. Conduct trend analysis on the unbalance value of traction rail return current, dynamic shunt resistance, and adjacent line interference to predict whether the working characteristics of the track section will deteriorate.

[0045] Example 3: This embodiment illustrates the process by which on-site maintenance personnel of station signaling use this device to collect data and analyze faults in station track circuits. In practice, this device mainly includes a test unit, a handheld terminal, and PC software.

[0046] In practice, maintenance personnel install the test unit near the choke transformers at both the power supply and receiving ends of the track circuit. The current on the two rail leads is collected by two current transformers, and the voltage is measured through the voltage acquisition terminals. During installation, a handheld terminal connects to the test unit via Bluetooth. The handheld terminal is used to calibrate the test unit's time, ensuring that the timelines of the data collected by the power supply and receiving test units are consistent. After the test unit is wired, the monitoring data can be read through the handheld terminal. After testing, the test unit is removed from the field, and the SD card from the test unit is connected to the card reader on the handheld terminal to import the data. For data analysis, dedicated analysis software is opened on a PC to analyze the test data and generate a test report.

[0047] like Figure 1 - Figure 5 As shown, Example 3 provides a method for analyzing the operating characteristics of a track circuit, which includes the following steps: 1. Maintenance personnel installed the test unit onto the choke transformers at the power supply and receiving ends of the track circuit, respectively.

[0048] 2. Maintenance personnel configure the acquisition mode and calibrate the clock of the test unit using a handheld terminal, and then read the current real-time measurement value through the handheld terminal.

[0049] (1) Set the acquisition mode. Select different acquisition modes according to the track circuit system on site.

[0050] (2) Obtain the current time of the test unit and synchronize the test unit's time to ensure that the clock module of each test unit is synchronized with the handheld terminal and that the test time axis of each unit is the same.

[0051] (3) Online data query: query the current working status of the test unit and obtain the data values ​​collected by the sensor.

[0052] 3. After the measurement task is completed, remove the test unit and import the data collected by the test unit into the software of the handheld terminal via SD card.

[0053] 4. In the PC software, summarize the test data of the handheld terminal, and query and analyze the data according to the on-site faults or abnormal situations.

[0054] 5. Select different analysis function modules according to the different types of fault diagnosis. (1) Branching characteristic analysis: ① Select to enter the branch characteristic analysis module ② Select the test records to be analyzed ③ Based on the on-site test results, select a section of track in the branching state and an adjacent time period. ④ Select the time point for adjusting the state within this time period to assist in calculation. ⑤ Input information such as the track length, number of compensation capacitors, and capacitance value of the track circuit section. ⑥ The PC-based analysis system calculates the equivalent shunt resistance data for this time period. ⑦ Present the trend of the equivalent shunt resistance and generate an analysis report with reference to other test data.

[0055] (2) Interference analysis of adjacent lines ① Select to enter the adjacent line interference analysis module ② Select the records to be analyzed ③ Select a time period to be analyzed or the entire test period. ④ The PC-based analysis system automatically analyzes the test data to determine if there is any adjacent line interference within the corresponding time period and generates an analysis report. (3) Traction return interference analysis ① Select to enter the traction return flow analysis module ② Select the records to be analyzed ③ Select a time period to be analyzed or the entire test period. ④ The PC-based analysis system automatically calculates the 50Hz interference and imbalance coefficient at each time point based on the test data. The PC-based analysis system analyzes the calculation results, automatically presents data for risky time periods, and generates analysis reports.

[0056] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions will not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A system for analyzing the operating characteristics of a track circuit, characterized in that, include: The traction rail return current monitoring module is used to monitor the line parameters on the lead wire between the choke transformer and the rail and extract its 50Hz component. The dynamic shunt resistance monitoring module establishes a mathematical model of the transmission loop based on the line parameters, calculates the shunt resistance-time curve in real time, and obtains the dynamic shunt resistance. The adjacent line interference monitoring module is used to extract the locomotive signal information current frequency component from the line parameters and monitor adjacent line interference. The frequency signal extraction module is used to output frequency domain signals through the MCU using digital filtering and fast Fourier transform algorithms, and to calculate the corresponding signal current value according to the frequency points of different signals. The traction rail return current monitoring module is used to monitor the line parameters on the lead wire between the choke transformer and the rail, and its workflow for extracting the 50Hz component is as follows: By installing choke transformers on both sides of the insulation joint and connecting the center points of the two choke transformers with a center connecting plate, the rail return current path is connected. Then, the current on the lead wire between the choke transformer and the rail is monitored, the 50Hz component is extracted, the rail return current is monitored, and the unbalanced rail return current is calculated. The dynamic shunt resistance monitoring module, based on the line parameters, establishes a mathematical model of the transmission loop and calculates the shunt resistance-time curve in real time. The workflow for obtaining the dynamic shunt resistance is as follows: Based on the uniform transmission line theory and the track section length and ballast type, a mathematical model of the transmission loop is established. The output is the track signal voltage and current at a frequency of 25Hz from the sending side rail lead-in line, and the input is the track signal voltage and current from the receiving side rail lead-in line. The equivalent shunt resistance of the train is calculated in real time, thus generating shunt resistance-time curve data to obtain the dynamic shunt resistance, expressed as: wherein represents the reflection coefficient at time represents the equivalent shunt resistance at time represents the intrinsic impedance of the track circuit, and according to the historical curve data of the dynamic shunt resistance, the working characteristics of the shunt state of one section are tracked, and maintenance basis is provided for the on-site maintenance personnel.​​ The adjacent line interference monitoring module is used to extract the locomotive signal information current frequency component from the line parameters. The workflow for monitoring adjacent line interference is as follows: When a train enters an adjacent track section and that section requires locomotive signal information, it represents an interference source. The locomotive signal information creates interference in the signal transmission loop of this track section through spatial coupling and ground conduction. By monitoring the current on the rail leads of the choke transformer, the frequency components of the locomotive signal information are extracted, including four frequency points: 1700Hz, 2000Hz, 2300Hz, and 2600Hz. An observation window is then constructed. For time series signals Perform a sliding Fourier transform, the expression is: In the formula, Indicates time Time to frequency The time-frequency energy spectral density value at that location, Indicates the length of the time window Integrating the signal from within arrive , Indicates time The time function of the original signal being observed. It is a window function. Indicates center alignment at Symmetrical windows, The complex exponential function is used to extract frequency. The signal components, It is the imaginary unit. Indicates the first The frequency value of each frequency component This represents the current time point in the scan. Represents the time variable Integrate the points.

2. The track circuit operating characteristic analysis system according to claim 1, characterized in that, The adjacent line interference monitoring module is used to extract the locomotive signal information current frequency component from the line parameters. The workflow for monitoring adjacent line interference is as follows: When a locomotive signal information frequency point from an adjacent track section is detected on the choke transformer lead wire of this track section, it indicates the presence of adjacent line interference. When the current of the adjacent line interference exceeds a preset value, on-site maintenance personnel resolve the adjacent line interference by lowering the output voltage of the locomotive signal information power supply in the adjacent section. The expression is: In the formula, This indicates the output voltage after the interference occurred. This represents the signal source voltage when there is no interference. It is a regulating factor used to control the sensitivity of voltage regulation. Indicates time The instantaneous value of the adjacent line interference current at time . This indicates the minimum disturbance value at which intervention and adjustment are needed. This represents the current value at which the interference reaches a critical threshold. This indicates the current disturbance as a linear proportion of the alarm and critical threshold.

3. The track circuit operating characteristic analysis system according to claim 2, characterized in that, The frequency signal extraction module, which uses the MCU to output frequency domain signals through digital filtering and fast Fourier transform algorithms, and calculates the corresponding signal current values ​​based on the frequency points of different signals, works as follows: Using a single current transformer, the analog current is converted into a signal that can be processed by an MCU microcontroller based on an ADC analog-to-digital converter. The MCU then employs a digital filtering algorithm to filter out components other than track circuit current, traction rail return current, and locomotive signal information frequencies. The expression is: In the formula, Indicates the first The filtered signal value at each time point. Is seeking The sum of, It is an index variable The range is from 0 to common item, Indicates the filter for the first The weight value of each delayed input, It is the first in the original input signal The value of each sampling point represents the current time step back. The value of the step.

4. The track circuit operating characteristic analysis system according to claim 3, characterized in that, The frequency signal extraction module, which uses the MCU to output frequency domain signals through digital filtering and fast Fourier transform algorithms, and calculates the corresponding signal current values ​​based on the frequency points of different signals, works as follows: The Fast Fourier Transform algorithm converts the filtered time-domain signal into a frequency-domain signal for output, expressed as: In the formula, Indicates the first Complex frequency domain output at each frequency point Indicates to arrive Accumulate. It is an index variable The range is from 0 to common item, Indicates the first Filtered current signal values ​​at each time-domain sampling point The rotation factor is used to project a time-domain signal onto the frequency domain. The base of the natural logarithm, It is the imaginary unit. To represent the angle of a complete sine wave, The frequency point index ranges from 0 to... , This represents the total number of sampling points in the Fast Fourier Transform. A spectral reconstruction factor is added based on the frequency of different signals to calculate the corresponding signal current value. The expression is: In the formula, Indicates the first Estimated current amplitude at each frequency point The first one defined Spectral leakage compensation factor at each frequency point This indicates the turns ratio of the current transformer. This represents the voltage-to-digital gain conversion factor of the ADC analog-to-digital converter. Indicates the first Window function weights for each point The cosine function is used to describe the response of a window function under frequency shift conditions. It is the Fast Fourier Transform (FFT) The center frequency of each frequency point Represents the actual frequency components in the actual signal. Indicates the sampling period.

5. A method for analyzing the operating characteristics of a track circuit, based on the track circuit operating characteristic analysis system according to any one of claims 1-4, characterized in that, Includes the following steps: S1. By monitoring the line parameters on the lead wire between the choke transformer and the rail, the 50Hz component is extracted. S2. Based on the line parameters, establish a mathematical model of the transmission loop, calculate the shunt resistance-time curve in real time, and obtain the dynamic shunt resistance. S3. Extract the locomotive signal information current frequency component from the line parameters and monitor adjacent line interference; S4. The MCU uses digital filtering and fast Fourier transform algorithms to output frequency domain signals and calculates the corresponding signal current values ​​based on the frequency points of different signals.

6. The method for analyzing the operating characteristics of a track circuit according to claim 5, characterized in that, In step S1, the method for extracting the 50Hz component by monitoring the line parameters on the lead wire between the choke transformer and the rail is as follows: By installing choke transformers on both sides of the insulation joint and connecting the center points of the two choke transformers with a center connecting plate, the rail return current path is connected. Then, the current on the lead wire between the choke transformer and the rail is monitored, the 50Hz component is extracted, the rail return current is monitored, and the unbalanced rail return current is calculated. In step S2, based on the line parameters, a mathematical model of the transmission loop is established, and the curve of shunt resistance versus time is calculated in real time. The method for obtaining the dynamic shunt resistance is as follows: Based on the uniform transmission line theory and the track section length and ballast type, a mathematical model of the transmission loop is established. The output is the track signal voltage and current at a frequency of 25Hz from the sending side rail lead-in line, and the input is the track signal voltage and current from the receiving side rail lead-in line. The equivalent shunt resistance of the train is calculated in real time, thus generating shunt resistance-time curve data to obtain the dynamic shunt resistance, expressed as: In the formula, Indicates time Reflection coefficient at time 10:00 Indicates time The equivalent shunt resistance at time . It represents the intrinsic impedance of the track circuit, and based on the historical curve data of the dynamic shunt resistor, it tracks the operating characteristics of the shunt state of one section, providing a maintenance basis for on-site maintenance personnel.

7. The method for analyzing the operating characteristics of a track circuit according to claim 6, characterized in that, In step S3, the method for extracting the locomotive signal information current frequency component from the line parameters and monitoring adjacent line interference is as follows: When a train enters an adjacent track section and that section requires locomotive signal information, it represents an interference source. The locomotive signal information creates interference in the signal transmission loop of this track section through spatial coupling and ground conduction. By monitoring the current on the rail leads of the choke transformer, the frequency components of the locomotive signal information are extracted, including four frequency points: 1700Hz, 2000Hz, 2300Hz, and 2600Hz. An observation window is then constructed. For time series signals Perform a sliding Fourier transform, the expression is: In the formula, Indicates time Time to frequency The time-frequency energy spectral density value at that location, Indicates the length of the time window Integrating the signal from within arrive , Indicates time The time function of the original signal being observed. It is a window function. Indicates center alignment at Symmetrical windows, The complex exponential function is used to extract frequency. The signal components, It is the imaginary unit. Indicates the first The frequency value of each frequency component This represents the current time point in the scan. Represents the time variable Integrate points; When a locomotive signal information frequency point from an adjacent track section is detected on the choke transformer lead wire of this track section, it indicates the presence of adjacent line interference. When the current of the adjacent line interference exceeds a preset value, on-site maintenance personnel resolve the adjacent line interference by lowering the output voltage of the locomotive signal information power supply in the adjacent section. The expression is: In the formula, This indicates the output voltage after the interference occurred. This represents the signal source voltage when there is no interference. It is a regulating factor used to control the sensitivity of voltage regulation. Indicates time The instantaneous value of the adjacent line interference current at time . This indicates the minimum disturbance value at which intervention and adjustment are needed. This represents the current value at which the interference reaches a critical threshold. This indicates a linear ratio of the current disturbance to the alarm and critical thresholds; In step S4, the MCU outputs a frequency domain signal using a digital filtering algorithm and a fast Fourier transform algorithm, and calculates the corresponding signal current value based on the frequency points of different signals as follows: Using a single current transformer, the analog current is converted into a signal that can be processed by an MCU microcontroller based on an ADC analog-to-digital converter. The MCU then employs a digital filtering algorithm to filter out components other than track circuit current, traction rail return current, and locomotive signal information frequencies. The expression is: In the formula, Indicates the first The filtered signal value at each time point. Is seeking The sum of, It is an index variable The range is from 0 to common item, Indicates the filter for the first The weight value of each delayed input, It is the first in the original input signal The value of each sampling point represents the current time step back. The value of the step; The Fast Fourier Transform algorithm converts the filtered time-domain signal into a frequency-domain signal for output, expressed as: In the formula, Indicates the first Complex frequency domain output at each frequency point Indicates to arrive Accumulate. It is an index variable The range is from 0 to common item, Indicates the first Filtered current signal values ​​at each time-domain sampling point The rotation factor is used to project a time-domain signal onto the frequency domain. The base of the natural logarithm, It is the imaginary unit. To represent the angle of a complete sine wave, The frequency point index ranges from 0 to... , This represents the total number of sampling points in the Fast Fourier Transform. A spectral reconstruction factor is added based on the frequency of different signals to calculate the corresponding signal current value. The expression is: In the formula, Indicates the first Estimated current amplitude at each frequency point The first one defined Spectral leakage compensation factor at each frequency point This indicates the turns ratio of the current transformer. This represents the voltage-to-digital gain conversion factor of the ADC analog-to-digital converter. Indicates the first Window function weights for each point The cosine function is used to describe the response of a window function under frequency shift conditions. It is the Fast Fourier Transform (FFT) The center frequency of each frequency point Represents the actual frequency components in the actual signal. Indicates the sampling period.

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