A method for identifying a fault section of a railway AT power supply catenary based on a special flow interaction

Abstract

This invention relates to the field of fault detection and location technology for railway power supply systems. Specifically, it discloses a method for identifying fault sections in railway AT power supply contact networks based on special-type interconnects. This method solves the problem that existing railway AT power supply traction networks may make mistakes in determining fault sections by relying solely on electrical quantities when a fault occurs near the AT substation. The method involves installing a wireless communication sensor with a built-in special-type interconnect near the AT substation's connection point towards the section substation. After the data is collected and processed by a centralized data receiving device, the data is uploaded to a communication server. The server uses the GOOSE communication protocol to communicate with the fault location device at the AT substation via Ethernet. The sensor's activation signal and the collected electrical parameters are uploaded to the traction substation's fault location device through the fault location channel between the traction substation and the AT substation. Combined with AC sampling data from each substation, the method achieves accurate identification of the fault section, accurately guiding maintenance personnel to reach the fault location as quickly as possible for repair, troubleshooting, and restoration of normal power supply.

Description

Technical Field

[0001] This invention relates to the field of fault detection and location technology for railway power supply systems, specifically to a method for identifying fault sections in railway AT power supply contact networks based on special-type current interconnection. Background Technology

[0002] The AT (Automatic Transmission) power supply traction network is a core component of the high-speed railway power supply system, and its operational stability directly affects the safe and efficient operation of the high-speed railway. During the operation of the AT power supply traction network, when a fault occurs near an AT depot, the existing fault section identification strategy cannot adapt to the traction network current distribution characteristics of that area. This easily leads to incorrect fault section identification, which in turn significantly reduces the accuracy of the fault location system, prolongs fault investigation and repair time, and affects the reliability of the railway power supply system and train operation efficiency.

[0003] Existing methods for fault location in railway overhead contact systems are mostly based on current data collected by traditional current transformers. They lack interval discrimination logic for special areas near the AT substation. Relying solely on conventional electrical parameters cannot accurately locate fault intervals near the AT substation. There is an urgent need for a fault interval discrimination method that adapts to the short-circuit current distribution characteristics near the AT substation, has high sampling accuracy, and high reliability. Summary of the Invention

[0004] This invention addresses the technical problems of incorrect fault section identification and low ranging accuracy in existing high-speed railway AT power supply traction network AT substations. It provides a fault section identification method for railway AT power supply contact network based on a special type of wireless communication interconnect. This method achieves high-precision current acquisition through a special type of wireless communication interconnect. Combined with sensor deployment at specific locations and fault identification logic, it accurately adapts to the current distribution characteristics of the traction network near the AT substation, significantly improving the accuracy of fault section identification and ranging accuracy.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: a method for identifying fault sections in railway AT power supply contact networks based on special type current interconnection, comprising the following steps:

[0006] S1. Install multiple built-in special-type current-interchange wireless communication sensors on the catenary and positive feeder lines of the contact network near the power supply point of the AT substation in the direction of the substation, and deploy a data collection device on the outer wall of the AT substation near the line side. The data collection device establishes a wireless communication connection with the sensors. At the same time, the data collection device is connected to the communication server of the AT substation integrated automation system through wired serial communication.

[0007] S2. The data centralization device provides timing to each wireless communication sensor to achieve synchronous sampling of all sensors. The sensors transmit current through the special current mutual induction contact wire and positive feeder.

[0008] S3. The sensor detects the incremental values ​​of the catenary current and the positive feeder current in real time. When either current increment exceeds the set value, the sensor starts fault recording, collects electrical data for 6 cycles before the fault and 10 cycles after the fault, and extracts the effective value data of the maximum fault current for 1 cycle, which is then transmitted to the data centralization device via wireless communication. The set value is set according to the maximum current increment value when a single locomotive or EMU is in operation.

[0009] S4. The data centralization device receives normal monitoring data and fault recording data uploaded by the wireless sensor. After parsing and processing the data, it forwards the data to the communication server through the protocol converter using the serial port 101 protocol.

[0010] S5. The communication server converts the received data into GOOSE communication protocol data, uploads the time-stamped fault data to the AT fault ranging substation through the station control layer switch, and then the fault ranging substation uploads the data to the fault ranging master station through the fault channel.

[0011] S6. After receiving the data, the fault ranging master station determines whether it has received the start signal of any sensor. If it has, it determines that the fault occurs in the second section of the power supply arm, and then calculates the specific location of the fault by combining the electrical parameters of the ranging device. If it has not received the signal or the data upload timeout occurs, it determines that the fault is not in the second section, that is, the fault is in the first section.

[0012] S7. The fault location master station uploads the fault section determination results and specific distance measurement data to the background system of the traction substation through the fault channel. Staff can obtain the fault section and location information through the background system, carry out fault investigation and repair work, and complete the entire fault section identification process.

[0013] In a preferred embodiment of the present invention, in S1, four built-in special-type wireless communication sensors are installed on the catenary and positive feeder lines of the contact network near the AT power supply point of the railway AT power supply traction network in the direction of the substation, corresponding to the downlink T1 phase, downlink F1 phase, uplink T2 phase, and uplink F2 phase, respectively.

[0014] A data centralization device is deployed on the outer wall near the line side of the AT station. This device establishes wireless communication connections with four sensors, with a communication distance of no more than 50 meters. Simultaneously, the data centralization device is connected to the communication server of the AT station's integrated automation system via an RS232-to-RS485 converter. The sensors are open-type current transformers, housing a special-type current transformer, battery, supercapacitor, sampling and logic judgment circuitry, power management, and wireless communication circuitry. The internal circuit boards are sealed and secured with a fastening structure to ensure stable fixation to the contact wire and positive feeder conductors.

[0015] In a preferred embodiment of the present invention, in S2, the data centralization device has a built-in timing module that sends timing information to each sensor, enabling synchronous sampling by all sensors. The sensors transmit current to the catenary and positive feeder of the contact network via a special-type current transformer. One output voltage of the special-type current transformer is sent to the sensor's sampling circuit, while the other output charges a supercapacitor. The supercapacitor and battery form a power supply module. The power management circuit rationally allocates power according to the sensor's power consumption and the intermittent power supply characteristics of the contact network line, ensuring continuous and stable sensor operation. The special-type current transformer has a current acquisition accuracy of 0.5 class and a maximum induced current of 5000A, enabling precise acquisition of large current changes near the AT (Anti-Torrent Station) and adapting to the current distribution characteristics of the area.

[0016] In a preferred embodiment of the present invention, in step S3, the sensor's sampling and logic judgment circuit continuously detects the incremental values ​​of the catenary current and the positive feeder current, comparing these two current increments with a set value. This set value is configured to avoid the maximum current increment during normal operation of a single locomotive or EMU, preventing false judgments triggered by current fluctuations during normal locomotive operation. When the incremental value of the catenary current or the positive feeder current exceeds the set value, a fault is determined to have occurred. The sensor immediately activates the fault recording function, collecting electrical data for the 6 cycles before and 10 cycles after the fault, fully recording the current change characteristics before and after the fault. Simultaneously, it extracts the effective value data of the maximum current cycle during the fault process and actively transmits it to the data centralization device via wireless communication.

[0017] In a preferred embodiment of the present invention, in step S4, the data centralization device receives normal monitoring data and fault recording data uploaded by four sensors, parses and organizes the data, and adds time scales. The data centralization device is powered by a battery and solar panel or by AC / DC power supply from the AT plant's internal AC / DC power supply, with an output power of DC12V or DC220V to ensure continuous power supply. The data centralization device integrates an RS232 interface and forwards the parsed remote signaling information and telemetry information to the communication server via the serial port 101 protocol. The remote signaling information includes status information such as low voltage alarm of the collection unit battery, short circuit / grounding alarm of phases T1 / F1 / T2 / F2, and undervoltage alarm of each phase battery. The telemetry information includes electrical parameters such as collection unit battery voltage, load current of each phase, temperature, battery voltage, fault current, and electric field strength. The data centralization device detects the communication status with the four sensors respectively and synchronously uploads the communication status to the fault location system for easy system status monitoring.

[0018] In a preferred embodiment of the present invention, in step S5, protocol conversion and data upload are performed as follows: The communication server acts as a protocol converter, converting the received serial port 101 protocol data into GOOSE communication protocol data. The time-stamped fault data is then uploaded to the fault ranging substation of the AT institute via the station control layer switch. The fault ranging substation then uploads the data to the fault ranging master station via the fault channel. The communication server is connected to the communication management unit via the station control layer switch. The communication management unit accurately synchronizes the time for the communication server, and then the communication server synchronizes the time for the data centralization device, achieving full system clock synchronization of the sensors, data centralization device, communication server, and fault ranging system, ensuring the consistency of data time stamps. The communication server detects the communication status with the data centralization device and feeds back the communication status to the integrated automation system.

[0019] In a preferred embodiment of the present invention, in S6, after receiving fault data, the fault ranging master station first determines whether it has received a start signal from any of the four sensors. If a sensor start signal is received, it directly determines that the fault occurs in the second interval. Then, combined with the electrical parameters such as voltage and current collected by the ranging device, it calculates the specific location of the fault, achieving dual positioning of the fault interval and the specific location. If no sensor start signal is received, or the data upload times out, it determines that the fault does not occur in the second interval. When a fault occurs and reclosing occurs on a permanent fault, due to the short reclosing time interval, the data concentrator can only upload the data from the first fault. At this time, the fault ranging master station first determines the fault interval based on the sensor start signal, and then calculates the fault location using the reactance method during the second full disconnection and direct supply, without needing to predetermine the interval, thus ensuring the fault ranging accuracy in the reclosing scenario.

[0020] Compared with the prior art, the beneficial effects of the technical solution of the present invention are as follows:

[0021] (1) This invention installs a built-in special current sensor at a designated location on the AT line. The special current sensor has a current acquisition accuracy of 0.5, a synchronous sampling accuracy of 1ms, and a maximum induced current of 5000A. It can accurately acquire the current change of the AT line near the fault and adapt to the current distribution characteristics of the traction network in the area.

[0022] (2) The present invention designs a customized fault section discrimination logic, which directly determines the fault of the second AT section near the AT based on the sensor start signal. This breaks through the technical bottleneck that the existing method cannot adapt to the current distribution characteristics near the AT, greatly improves the accuracy of fault section judgment, and avoids the ranging deviation caused by section judgment error.

[0023] (3) The sensor of the present invention adopts a dual power supply mode of special current mutual self-powered power supply + battery, combined with the power distribution strategy of power management circuit, which can adapt to the intermittent power supply characteristics of contact network line and ensure the continuous and stable operation of the sensor; at the same time, the sensor has an IP67 protection level and the data collection device has an IP55 protection level, which can adapt to the complex outdoor operating environment of railway and improve the reliability of the equipment.

[0024] (4) This invention constructs a full-link data transmission and clock synchronization system of “sensor-data centralization device-communication server-fault ranging system” to realize synchronous data acquisition, reliable transmission and accurate time synchronization. At the same time, it sets up communication status detection and data upload timeout judgment mechanism to further improve the reliability and anti-interference ability of fault interval judgment. Attached Figure Description

[0025] Figure 1 This is a structural diagram of the special type of fluid interconnection system in this embodiment.

[0026] Figure 2 This is a schematic diagram of the installation positions of the contact wire characteristic flow in this embodiment.

[0027] Figure 3 This is a schematic diagram of the data acquisition and reception system in this embodiment. Detailed Implementation

[0028] The invention will be further described in detail below with reference to a specific engineering implementation case. This embodiment takes the fault section identification of the railway AT power supply contact network of one power supply arm of a traction substation in Hangzhou-Quzhou as the application scenario, and implements the fault section identification method based on special current interaction of the present invention.

[0029] Step 1: Equipment Deployment and Networking

[0030] like Figures 1-2 As shown, four built-in special-type current transformer sensors are installed near the junction of the catenary and the feeder on the outer side of the AT substation, towards the substation. These sensors correspond to phases T1, F1, T2, and F2, respectively. The sensors are open-type current transformers, sealed and fixed to the conductors using fastening mechanisms. A data centralization device is deployed on the elevated structure near the line side wall of the AT substation or near the corresponding support pillar of the feeder switch, ensuring a wireless communication distance of no more than 50 meters with the sensors. The data centralization device establishes wireless communication with the sensors. The data centralization device is connected to the communication server of the AT substation feeder protection panel via an RS232 to RS485 converter. The RS485 cable uses 0.5mm² shielded twisted-pair cable with terminating resistors at both ends. The communication server is connected to the station control layer switch to achieve network communication with the fault location substation.

[0031] Step 2: System time synchronization and sampling

[0032] The data centralization device has a built-in timing module that sends timing information to four sensors, achieving a synchronous sampling accuracy of 1ms. The sensors' special-type current transformers induct the current of the catenary wire and positive feeder of the overhead contact line. One output goes to the sampling circuit, and the other charges a supercapacitor. The supercapacitor, in conjunction with a battery, powers the sensors. The power management circuit allocates power according to the intermittent power supply characteristics of the overhead contact line, ensuring continuous operation of the sensors when no external power supply is available. In this embodiment, the current acquisition accuracy of the special-type current transformer is 0.5%, with a maximum induced current of 5000A, enabling precise acquisition of large current fluctuations near the AT (Anti-Torrent Station).

[0033] Step 3: Fault Detection and Waveform Recording

[0034] The sensor's current increment setting value is set to avoid the maximum current increment value of a single EMU train. The sensor detects the current increment of the catenary and positive feeder in real time. When a short circuit fault occurs, the current increment quickly exceeds the setting value. The sensor immediately starts fault recording, collects electrical data of 6 cycles before the fault and 10 cycles after the fault, and extracts the effective value data of the maximum fault current of 1 cycle. The data is then transmitted to the data centralization device via wireless communication.

[0035] Step 4: Data Aggregation and Forwarding

[0036] like Figure 3 As shown, after receiving fault data from the sensors, the data centralization device adds a timestamp and parses it into remote signaling and telemetry data, which is then forwarded to the communication server via the Serial Port 101 protocol. The remote signaling data includes short-circuit and grounding alarms for phases T1 / F1 / T2 / F2, while the telemetry data includes load current, fault current, and temperature for each phase. The data centralization device monitors the communication status with the four sensors in real time and uploads the data synchronously to the communication server. The transmitted content is shown in Tables 1 and 2.

[0037] Table 1: Remote Signaling Information Table.

[0038]

[0039] Table 2: Telemetry Information Table.

[0040]

[0041] Step 5: Protocol Conversion and Data Upload

[0042] The communication server converts serial port 101 protocol data into GOOSE protocol data, and uploads the time-stamped fault data to the AT fault ranging substation through the station control layer switch. The fault ranging substation then uploads the data to the fault ranging master station via the fault channel. At the same time, the communication server connects to the communication management unit through the station control layer switch to complete system time synchronization and ensure full-link clock synchronization.

[0043] Step 6: Fault Section Identification and Distance Measurement

[0044] After receiving the sensor's start signal, the fault location substation transmits the start signal and communication status information to the main station's fault location device via the fault location channel between the main station and the substation. When communication is normal and the transformer start signal is closed, the fault is directly determined to occur in the 2AT section of the AT substation. At this time, the electrical parameters of the fault location device are used to calculate the specific location of the fault point in the 2nd section. If communication is normal, and after a certain delay, the transformer start signal remains in the 1st section, then the fault point is located in the 1st section. When communication is interrupted, the main station's fault location device does not use the special current mutual start signal to determine the fault section, avoiding misjudgment.

[0045] This embodiment successfully achieves accurate identification of fault sections near the AT station using the method of the present invention, solving the problem of incorrect section identification by traditional methods in this area. The ranging accuracy reaches the design requirement of 500m. The equipment operates stably, has strong anti-interference ability, and is suitable for the complex outdoor environment of railways, effectively improving the fault detection efficiency and power supply reliability of the AT power supply contact network.

[0046] The above description is only a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for identifying fault sections in railway AT power supply contact networks based on special-type current interconnection, characterized in that, Includes the following steps: S1. Equipment Deployment and Networking: Install multiple built-in special-type wireless communication sensors on the catenary and positive feeder lines of the contact network near the network point of the AT power supply line of the railway AT power supply traction network towards the substation. Deploy a data collection device on the outer wall of the AT substation near the line side. The data collection device establishes a wireless communication connection with the wireless communication sensors. At the same time, the data collection device is connected to the communication server of the AT substation integrated automation system through wired serial communication. S2. System timing and synchronous sampling: The data centralization device provides timing to each wireless communication sensor to achieve synchronous sampling of all wireless communication sensors. The wireless communication sensors transmit current through the special current mutual induction contact wire and positive feeder. S3. Fault Detection and Waveform Recording: The wireless communication sensor detects the incremental values ​​of the catenary current and the positive feeder current in real time. When either current increment exceeds the set value, the wireless communication sensor starts fault waveform recording, collects electrical data for the 6 cycles before and 10 cycles after the fault, and extracts the effective value data of the maximum fault current for 1 cycle, which is then transmitted to the data centralization device via wireless communication. The set value is set according to the maximum current increment value when a single locomotive or EMU is in operation. S4. Data aggregation and forwarding: The data centralization device receives normal monitoring data and fault recording data uploaded by wireless communication sensors. After parsing and processing the data, it forwards the data to the communication server through the protocol converter using the serial port 101 protocol. S5. Protocol Conversion and Data Upload: The communication server converts the received data into GOOSE communication protocol data, uploads the time-stamped fault data to the AT fault ranging substation through the station control layer switch, and then the fault ranging substation uploads the data to the fault ranging master station through the fault channel. S6. Fault Section Identification and Distance Measurement: After receiving data, the fault distance measurement master station determines whether it has received the start signal of any wireless communication sensor. If it has, it determines that the fault occurs in the second section of the power supply arm, and then calculates the specific location of the fault by combining the electrical parameters of the distance measurement device. If it has not received the signal or the data upload timeout occurs, it determines that the fault is not in the second section, that is, the fault is in the first section. S7. Result Upload and Display: The fault ranging master station uploads the fault section judgment result and specific ranging data to the background system of the traction substation through the fault channel. Staff can obtain the fault section and location information through the background system, carry out fault investigation and repair work, and complete the entire fault section judgment process.

2. The method according to claim 1, characterized in that: In step S1, four wireless communication sensors are provided, corresponding to downlink phase T1, downlink phase F1, uplink phase T2, and uplink phase F2 respectively. The data collection device detects the communication status with the four wireless communication sensors and uploads it to the fault ranging system. The communication server detects the communication status with the data centralization device and feeds it back to the integrated automation system.

3. The method according to claim 1, characterized in that: In step S1, the wireless communication sensor is an open current transformer structure, with a built-in special current transformer, battery, supercapacitor, sampling and logic judgment circuit, power management and wireless communication circuit. The internal circuit board of the wireless communication sensor is sealed and fastened to the conductors of the contact network and positive feeder. One output voltage of the special current transformer is sent to the sampling circuit of the wireless communication sensor, and the other output voltage is used to charge the supercapacitor. The supercapacitor and the built-in battery form a power supply module. The power management circuit allocates power according to the power consumption of the wireless communication sensor and the intermittent power supply characteristics of the contact network.

4. The method according to claim 1, characterized in that: In step S4, the power supply of the data centralization device is either a battery + solar panel or AC / DC power supply from the AT plant; the data centralization device integrates an RS232 interface, and establishes long-distance wired communication with the communication server through an RS232 to RS485 converter; the RS485 cable uses 0.5mm² shielded twisted pair cable, with terminating resistors installed at both ends.

5. The method according to claim 1, characterized in that: In step S4, the data forwarded by the data centralization device includes remote signaling information and telemetry information. The remote signaling information includes low voltage alarm of the collection unit battery, short circuit / grounding alarm of each phase, and undervoltage alarm of each phase battery. The telemetry information includes collection unit battery voltage, load current of each phase, temperature, battery voltage, fault current and electric field strength.

6. The method according to claim 1, characterized in that: In steps S4 and S5, the communication server is connected to the existing communication management unit within the institute through the station control layer switch. The communication management unit synchronizes the time for the communication server, and then the communication server synchronizes the time for the data centralization device, thereby achieving clock synchronization of the entire system.

7. The method according to claim 1, characterized in that: In step S6, the set value of the data upload timeout is determined based on the data transmission delay of the concentrator during actual on-site testing. When a fault occurs and the circuit is reclosed to a permanent fault, the fault ranging master station first determines the fault range based on the wireless communication sensor start signal, and secondly, in the full disconnection power supply mode, the fault location is calculated using the reactance method. At this time, it is not necessary to determine the fault range.

8. The method according to claim 1, characterized in that: In step S1, the wireless communication distance between the data collection device and the wireless communication sensor does not exceed 50m.

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