QDJ-I Model Rail Breakage Monitoring Systemfor Semi-automatic Block Section

QDJ-I Model Rail Breakage MonitoringSystemfor Semi-automatic Block SectionNanchang Railway Tianhe Construction Co., Ltd.May 20171. OVERVIEW OF SYSTEMThe QDJ-I model rail breakage monitoring system for semi-automatic block section is no-track-circuit rail breakage monitoring equipment researched, developed and produced independently by the company. Research, development and design of the rail breakage monitoring mainly focus on conducting inspection by ensuring certain current to pass through each rail as a lead wire. In case of physical breakage and electric disconnection of the rail, the loop current is disconnected and alarm messages are sent. Currently, there are multiple rail breakage monitoring schemes, including AC/DC track circuit monitoring, carrier wave monitoring, and ultrasonic wave monitoring. Which rail breakage monitoring scheme costs less but presents high reliability? After going through many times of research and comparison, the research group decided to develop a new energy-saving jointless section track circuit. The purpose of real-time rail breakage monitoring can be achieved by loading carrier signals on rails, and transmitting signals among different field transceivers, with a broken rail differentiation range below 1Km. Besides, this system is also able to monitor and judge the train travel direction and display the whole process of section occupation and clearance. This scheme not only guarantees train travel safety, but also realizes higher efficiency with less personnel, as well as lower cost.2. APPLICATION FIELD AND WORKING PRINCIPLE OF SYSTEM2.1 Application fieldThe section rail breakage monitoring system is used to monitor breakage of rails having no track circuits in real time, and is applicable for both electric and non-electric sections.2.2 Structure and working principle of system2.2.1 System compositionA number of trackside data sending and receiving equipment (“field transceivers” hereinafter) for monitoring overall rail status are installed, using remote cloud as the server and a fixed PC client and a mobile APP as the monitoring points. The information of all the field transceivers is relayed to terminal field transceivers (“managers” hereinafter), which then send the information to the remote server through wireless transceiving devices, so that the users can access the database of the remote server through the fixed client and mobile APP.The manager 1 and field transceivers transmit the data in a relay way to the manager N, the manager N collects the information transmitted from the manager 1 and field transceivers, pack and communicate it to a GPRS module through RS-485, and the GPRS module sends the monitoring data to a control center once every 15 seconds. The control center stores and analyzes the data sent wirelessly from the GPRS module, to provide real-time monitoring data, graphics and alarm messages to the PC client, and send rail breakage alarm messages and rail breakage recovery messages to adesignated phone number. The PC client mainly functions to display database data, analysis and processing results and monitoring curves of the control center, and various user operation and alarm interfaces. In case of rail breakage or monitoring equipment failure, audible and visual alarms are made to warn the person on duty of equipment abnormality and to take prompt measures to prevent accidents.The managers and field transceivers are installed at an interval ≤1KM, and the gauge bars between the rails are all insulated ones. For sections in severe environment, i.e., at low leakage resistance of the track bed, the interval can be adjusted to improve the monitoring precision.The system is mainly composed of the field transceivers, managers, GPRS module, solar power supply, control center, fixed client and mobile client.2.2.2 Working principle of systemThe system finds rail breakage by checking physical and electric disconnection of the rail through carrier current. 13.5KHz FM signals are used, such that the electrical loss of rail transmission is low, and the transmission distance conforms to the requirements.2 managers are set within each section and a field transceiver is set within each kilometer. The manager 1 and field transceivers send information once every 15 seconds in a relay way, the field transceiver 2, field transceiver3 and field transceiver n transmit the information in sequence to the manager through the rail, and the manager checks the electric disconnection status of the rail on the basis of the status of the rail-transmitted/ received signals received from the manager 1, field transceiver 2 and field transceiver n. Then the manager sends the information to the GPRS module through RS485 communication, the GPRS module sends the data to the control center database, and the control center stores and analyzes the data sent from the GPRS module in a wireless way. The client is provided with real-time monitoring data and graphics, and the processed data can be displayed, alarmed, stored, printed, etc. The system client includes the fixed client and mobile client. The fixed client is suitable for the existing computer, through which the cloud server can be logged in. After the server database is logged in by using the fixed client, the processed data can be displayed, alarmed, stored, printed, etc. The mobile client is a mobile APP, through which the cloud server can be logged in to call database data. Both the fixed and mobile clients can be used to monitor the data information of the field transceivers and managers, rail occupancy and clearance status in a section, rail breakage status and system equipment failure information in real time.3. EQUIPMENT CONFIGURATION OF SYSTEM3.1 Control centerThe control center is the place where the rail breakage monitoring data is collected. It includes hardware (like hosts and memories) and backup software, and provides centralized data storage, backup and management services for digitalization. In consideration of the need to manage information of several sections by the railbreakage server, a cloud server with 2-core CPU, 4GB memory, 2M bandwidth and 40GB system disk capacity is used. It also provides network security and management services, including an on-line anti-virus system, invasion detection system, log recording system, network performance monitoring system, etc.3.2 Client configurationFixed client: a Pentuin series computer (or the existing computer);Mobile client: a mobile phone of Android 4.4 version. It is applicable for a phone of Android 4.4 version or above.3.3 Configuration of sampling and monitoring system for section equipment Field transceiver Several (≤1Km/set);Manager 2 sets;Battery Several;Solar panel and charger Several;GPRS module 2 sets.3.4 Field transceiverThe field transceiver mainly functions to monitor the rail status by transmitting carrier signals through the rail, monitor the battery level of itself and failure status of the lightning protection device and of itself, and transmit data of other field transceivers. The field transceiver is composed of a power circuit, CPU, transceiving module 1, transceiving module 2, sleeping/wake-up circuit, etc.Description of the structure block diagram of the field transceiver: the battery provides power for the entire equipment; the CPU having large program memory, large internal RAM, watchdog, power failure detection function and strong interference resistance function is used; the high-precision crystal oscillator is used to provide clock for the CPU to realize accurate time synchronization and sleeping/wakeup; the LED lamp is used to indicate the working status; the CPU communicates with the carrier module through the serial interface; the lightning protection module provides lightning protection to the equipment. See the following diagram for the internal structure of the field transceiver.Structure block diagram of field transceiverThe output line of the field transceiver is connected to the rail through two plug-type power connecting lines. The circuit board and appearance of the field transceiver areas shown below.Circuit board of field transceiverAppearance of field transceiver3.5 ManagerThe manager mainly functions to monitor the rail status by receiving carrier signals transmitted through the rail, pack the collected data transmitted by the field transceivers through the rail, and communicate the data to the GPRS module through RS-485. The manager also monitors the battery level of itself and failure status of the lightning protection device and of itself. Description of the structure block diagram of the manager: the battery provides power for the entire equipment; the CPU having large program memory, large internal RAM, watchdog, power failure detection Solar panel Power processing andbattery status detection module High-precision crystal oscillator LED status indicating lamp Lightningprotection moduleCarrier input/output and protection module Carrier communicationand signal detection module 1 Carrier communicationand signal detectionmodule 2 RS232communicationinterfacefunction and strong interference resistance function is used; the high-precision crystal oscillator is used to provide clock for the CPU to realize accurate time synchronization and sleeping/wakeup; the LED lamp is used to indicate the working status; the CPU communicates with the carrier module through the serial interface; the lightning protection module provides lightning protection to the equipment. The manager has equipment monitoring functions. It can monitor failure of the manager, lightning protection module and battery, make alarms in case of such failure, monitor communication interruption of the GPRS module and make alarms in case of such interruption.The manager receives data from the field transceiver, packs it, and sends it to the GPRS module through the RS-485 interface, and the GPRS module periodically sends the data from the manager to the remote cloud server. See the following diagram for the internal structure of the manager.Structure block diagram of managerThe output line of the manager is connected to the rail through two plug-type power connecting lines. The circuit board and appearance of the manager are as shown below.High-precision crystal oscillatorLightning protection moduleCarrier input/output and protection module Carrier communicationand signal detection module 1 Carrier communicationand signal detectionmodule 2 RS232 communication interface 2 RS485communication interface 1 Wireless GPRS moduleLED statusindicating lampDC-DCVoltage stabilizer Detection module for charging status of standby battery Standbybattery Solar panelCircuit board of manager Appearance of manager4. FUNCTIONAL PARAMETERS AND CHARACTERISTICS OF SYSTEM 4.1 Technical indicators of system(1) Able to monitor rail breakage in non-electric/electric semi-automatic block sections.(2) Missing report rate for rail breakage: 0; alarm accuracy for rail breakage: 99.8%.(3) Distance of reference monitoring unit: ≤1Km.(4) Setting of remote parameters, including alarm interval, track bed parameters, battery level alarm threshold, etc.(5) Remote program upgrade, and remote setting of GPRS target address in alarm host.(6) The control center supports B/S mode, and is developed based on GIS map, having three map modes available: railway-specific map, 3D geographic map and planimetric map. The rail breakage alarm message is uploaded in real time, the map visually shows the section where the broken rail is located and the corresponding kimometers, and makes audible and visual alarms.(7) The client interface also has alarm display function. In the normal condition, the rail section box and equipment box in the client interface are in green; in case of rail breakage, the rail section box is in red, making audible and visual alarms; in case of monitoring equipment failure, the equipment box is in yellow or red, making audible and visual alarms; when a train occupies the section, the rail section box is in blue, and recovers when being cleared.(8) The client interface has data query function. The real-time curve, historical curve, historical data, train passing curve and alarm record can be inquired.(9) The alarm messages can be sent to the phone via SMS.(10) The server stores equipment information and alarm records for 6 months, the system updates the displayed data in real time and displays latest records of ≥100,000.(11) The manager is connected to the GPRS module through the serial interface byRS-485 serial communication with a baud rate of 2,400bps.(11) System data sampling time: 15s; relay transmission.Broken rail identification time: ≤1min; broken rail alarm time: ≤3min (delayed if the rails are occupied). For rail breakage recovery, alarm recovery identification time: ≤1min; alarm elimination time: ≤3min.(13) Equipment self-diagnosis alarm function, including alarms for low voltage (alarms are made if the voltage is down to 5.3V and eliminated if it rises to 5.5V) and failure of the lightning protection module, and alarms for failure of the managers and field transceivers (power failure and line disconnection); alarm time: ≤2min (delayed if the rail is occupied). Alarm recovery time for self-diagnosis: ≤2min.(14) Client working environment: -5℃~+40℃.(15) Service life: field transceivers, managers, solar panel and battery: >5 years.4.2 Technical indicators of manager(1) Static operating current: ≤50mA.(2) Dynamic operating current: ≤400mA.(3) Information receiving distance from field transceiver: ≥0.8Km for track bed resistance of 1.0Ω/Km, and ≥1Km for track bed resistance of 2.0Ω/Km.(4) Carrier center frequency: 13.5KHz±0.5KHz; frequency deviation: 4.0KHz.(5) Instantaneous sending power: ≥0.6W (peak-to-peak value: +2.0V, -2.0V).(6) Maximum number of field transceivers: ≥32.(7) Sampling cycle: ≤15S.(8) Working power: battery: DC5.5V~12V; power supply period without solar power: >7 days.(9) Insulation resistance: ≥25MΩ.(10) Withstand voltage: >1.2KV (AC, 60 seconds, 1mA).(11) Working environment: -40～85℃.(12) Ingress protection rating of equipment casing: IP65.4.3 Field transceiver of field transceiver(1) Static operating current: ≤50mA.(2) Dynamic operating current: ≤400mA.(3) Information receiving distance from field transceiver: ≥0.8Km for track bed resistance of 1.0Ω/Km, and ≥1Km for track bed resistance of 2.0Ω/Km.(4) Carrier center frequency: 13.5KHz±0.5KHz; frequency deviation: 4.0KHz.(5) Instantaneous sending power: ≥0.6W (peak-to-peak value: +2.0V, -2.0V).(6) Sampling cycle: ≤15S.(7) Working power: battery: DC5.5V~12V; power supply period without solar power: >7 days.(8) Insulation resistance ≥25MΩ.(9) Withstand voltage: >1.2KV (AC, 60 seconds, 1mA).(10) Working environment: -40～85℃.(11) Ingress protection rating of equipment casing: IP65.4.4. Technical characteristics(1) Effectiveness①This system monitors rail breakage through transceiving communication with a center frequency of 13.5K.②T he rails are considered as lead wires and the left and right rails are used as loops for information transmission.(2) Reliability①A larm missing and false alarms are prevented by judging between sudden change and gradual change of signal intensity.②T he SPD lightning protection network impairs interference of lightning and HV arc of overhead electric lines to system monitoring and transmission, helping improve the data reliability.(3) SecurityThe system has a framework relatively independent from the measured system. Failure of the latter does not affect normal operation of the former and vice versa. (4) ExpandabilityThe advanced and stable carrier transmission technology will be expanded to more fields to play more roles through further improvement and development.5. SYSTEM ADVANTAGES(1) The system monitors rail breakage through transceiving communication by using FM signals with a center frequency of 13.5K. The electrical loss of rail transmission is low, and the transmission distance conforms to the requirements.(2) Partial functions of jointless section track circuits are realized to monitor the train travel direction, and section occupation and clearance. The rail section box in the client interface is shown in blue, such that the train travel kilometers within the section can be completely mastered, and the train operation conditions can be known.When a train passes through the section, it is not judged whether rail breakage occurs. After the rain has passed, if the section cannot receive information sent from the rail, it is regarded as rail breakage in this section. In this way, the rail breakage alarm precision can be improved, and false alarms can be reduced.(3) The mobile APP is developed to provide a convenient query method for field operators and managers.6. INNOVATION POINTS OF SYSTEM(1) When a train occupies the section, the train wheel pairs are short-circuited from the two rails. Information cannot be received if rail breakage is checked by using the two rails as the transmission medium. This situation is regarded as rail breakage. To reduce false alarms, the sending current of the field transceivers and managers are smartly utilized to differentiate among three statuses of the sending current: short circuit, open circuit and normal status.(2) Partial functions of jointless section track circuits are used to judge between section occupation and clearance. The rail length in the section having no track circuit is divided into equal parts of ≤1.0Km. The field transceivers are installed at this interval. The train occupation/clearance in the rail section box in the client interface is shown in blue to show the train operation conditions. When a train passes through the section, it is not judged whether rail breakage occurs. After the rain has passed, if the section cannot receive information, it is regarded as rail breakage in this section. In this way, the rail breakage alarm precision can be improved, and false alarms can be reduced.7. MEANING OF SYSTEMThe rail breakage monitoring system monitors rail breakage in real time in an all-weather way. It makes audible and visual alarms promptly in case of rail breakage to warn the operators to take prompt measures, so as to prevent train derail and over-turning accidents because of the broken rail.The rail breakage monitoring equipment allows to accurately acquire data about occupation or clearance of the section from the clients. The monitoring data can be called at any time from the database, which provides great convenience for security management and real-time site monitoring of the rail status, and eliminates a blind spot in site security management.8. PROSPECT OF SYSTEMThe QDJ-I model rail breakage monitoring system for semi-automatic block section can be widely used to monitor breakage of rails having no track circuits in real time. It makes alarms promptly in case of rail breakage to warn the operators to take prompt measures, so as to prevent train derail and over-turning accidents because of the broken rail. It brings remarkable social benefits:(1) The rail breakage monitoring system for semi-automatic block section can be built with the least amount of resources to guarantee train travel safety.(2) The broken position of a rail can be quickly found by using this system.(3) The train travel kilometers within the section can be completely mastered by using this system.(4) The rail breakage judgment accuracy is improved and false alarms are minimized in the easiest way.Test Report of Shanghai Institute of Quality Inspection and Technical ResearchTest Report of ICAS Testing Technology Service (shanghai) Co., Ltd.。