Traditional Culture Encyclopedia - Traditional stories - On the overall composition of urban rail transit system
On the overall composition of urban rail transit system
Keywords: overall composition of urban rail transit system
1. transmission system
The transmission system is the most important subsystem. When designing the overall scheme and system capacity, the requirements of short-term construction and long-term development should be considered to ensure reliable system performance, expandable capacity and relatively flexible system construction.
In order to meet the needs of rail transit signal, power monitoring, disaster prevention, environment and equipment monitoring, automatic fare collection and voice transmission, the transmission system adopts optical communication as the main transmission medium. The logical topology structure of transmission network adopts double-ring structure, which ensures that the system can still provide better system recovery ability under fault conditions and improves the reliability of network operation. Network nodes and user interface modules are the only way for users to access the network. Client information is uploaded and downloaded through network nodes. Due to the diversity of information, the system can provide users with rich interface types. The network management system of transmission equipment adopts mature operating system, which has powerful functions and friendly interface. Operators can easily complete network configuration, management and maintenance.
2. Official telephone system
The official telephone system of rail transit is built as a private network, which consists of program-controlled switches, telephones and auxiliary equipment. The connection between the official telephone system and the public telephone network adopts automatic outgoing and incoming calls, and works through a 2M digital relay circuit. The telephone number should be incorporated into the unified number of the local public telephone network. The system functions mainly include: telephone exchange function, billing function, non-telephone service function (including data, fax and other non-telephone services), recovery control mode function, number storage and decoding function, circuit selection and release function, new service function (including new functions such as dialing reduction, hotline service, call prohibition, three-way call, call transfer, forced disconnection/forced insertion), maintenance management function, overvoltage and overcurrent protection and anti-interference function.
3. Private telephone system
Private telephone system is an important communication system, which provides an effective communication means for operation organization, power supply, equipment maintenance and disaster prevention and rescue. The system is mainly composed of dispatching switchboard, dispatching desk and dispatching extension, which are connected by transmission system. Dispatching switchboard is the core part of dispatching telephone subsystem, which consists of switches or switching modules with switching functions. The dispatching desk is located in the control center and is the operation console for dispatching business. The dispatching extension is an ordinary telephone, which is connected with the point-to-point dedicated audio channel provided by the switchboard through the transmission system.
The main functions of the system in practical application include: call function, selective call function (i.e. single call, group call, full call from dispatching desk to extension and total call or emergency call from extension to dispatching desk), conference function, recording function and maintenance management function.
4. Wireless communication system
Wireless communication system is a special system that provides communication means between fixed users such as dispatcher of control center, dispatcher of vehicle base and station attendant, and mobile users such as train drivers, disaster prevention, maintenance and public security. The wireless communication system adopts wired and wireless transmission modes. The central wireless equipment is connected with the wireless base stations of stations and vehicle bases through transmission systems, and each base station communicates with the mobile station through antenna space wave propagation or leakage cable radiation. According to the needs of operation and management, wireless communication system is equipped with traffic scheduling, disaster prevention scheduling, comprehensive maintenance, vehicle base scheduling and other systems. The system has dispatching communication functions such as single call, group call, full call, emergency call and call priority authority setting, and has functions such as recording, storage and monitoring.
5. Video monitoring system
The system provides operators with video information about train operation, disaster prevention and relief, and passenger guidance. The system consists of local station monitoring system, control center remote monitoring system, remote multi-channel signal transmission system and multimedia network management terminal. The system has the functions of monitoring, priority control, cyclic display, arbitrary freezing and locking, image selection, real-time video recording, camera range control, character superposition and so on.
Digital transmission is used for long-distance video signal transmission, and video coaxial cable is used for local video signal transmission. The video and control signals of the station and the control center are transmitted through the transmission system, and the number of digital video signals uploaded to the control center is only related to the number of channels that the control center needs to display at the same time, regardless of the number of front-end cameras. Therefore, there is no need to set a large-capacity video switching matrix and transmission equipment in the control center, and the system structure is simple.
6. Broadcasting system
Broadcasting system is a necessary means of urban rail transit organization. On the one hand, broadcast passengers and inform them of the relevant ride information; On the one hand, it is organized and directed accident rescue and disaster prevention broadcasting; In addition, relevant information can also be released to operators through broadcasting for cooperative work.
The system adopts modular design and bus structure, and consists of station level, center level and train broadcasting equipment. It has the functions of central broadcasting, radio broadcasting, pre-stored broadcasting information, automatic volume adjustment, automatic audio testing, remote control and so on. The system adopts two-level control mode: central broadcasting and station broadcasting. The audio signals and control signals output by the intelligent broadcasting station in the control center are transmitted to the stations through the transmission system through the RS422 channel provided by the high-quality voice card, and then connected to the station broadcasting equipment through the voice card, thus realizing the remote broadcasting organization and command of the control center.
7. Passenger Information System
The system is mainly composed of information management system and terminal passenger information display screen, and passenger information is transmitted through transmission system. Passenger information display screens are set up in all stations and passenger rooms along the whole line to display passenger information every hour, such as arrival, departure, boarding instructions, current affairs news, etc. , and has alarm linkage function to display relevant alarm information in case of emergency.
8. Clock system
In order to ensure the rail transit operation to serve passengers on time, unify the standard time of the whole line equipment and provide a unified timing signal, a clock system is set up. The system adopts GPS standard time information, and consists of a GPS standard clock signal receiving unit, a central primary master clock, monitoring equipment, a secondary master clock and a secondary clock. The system is equipped with digital synchronization equipment. The primary master clock receives the external GPS reference signal and calibrates the primary master clock. The primary master clock regularly sends time-coded signals to the secondary master clock, the slave clock of the control center and other systems that need to provide unified time information for calibration. The second master clock generates a time signal to provide the slave clock of the station. The master clock has the function of perpetual calendar, with the output and display of year, month, day, hour, minute and second. The clock can display hours, minutes and seconds. Its own time accuracy, the primary master clock is above 10-7 and the secondary master clock is above 10-6. The master clock and the secondary master clock are equipped with digital multi-output interfaces to provide timing signals for other systems.
9. Power supply and grounding system
The power supply of communication equipment should adopt the first-class load, and the power supply system should provide uninterrupted power supply with relatively stable voltage and frequency for communication equipment, with centralized monitoring and management functions.
Uninterruptible power supply system (UPS) is generally divided into two parts: UPS cabinet and storage battery. Offline UPS system or online UPS system can be used. Off-line UPS systems usually supply power directly to the load from the commercial power, and switch to the inverter instantly when the commercial power fails (practical for equipment with low requirements on power supply stability); On-line UPS system supplies power to the load after rectification and inversion by commercial power. When the main power supply fails, it is replaced by the battery. The inverter mode supplies power to the load, which is more stable than the previous mode. UPS system includes four working modes: normal working mode, battery working mode, static bypass mode and manual bypass working mode.
The grounding system shall be designed to ensure the safety of personnel and communication equipment and the normal operation of communication equipment. Communication equipment adopts comprehensive grounding mode, and the comprehensive grounding resistance value should not be greater than 1? The resistance values of protective grounding and lightning protection grounding of outdoor grounding body should not be greater than 10? .
10. Communication integrated network management system
In order to realize centralized management, maintenance and fault monitoring of communication subsystem, realize rapid fault location, and make it possible to repair faults as soon as possible, the rail transit communication system has specially constructed an integrated network management system. The system can monitor and manage transmission system, wireless communication system, telephone system, broadcasting system, video monitoring system and network management system itself.
The hardware part of the system is mainly composed of a remote terminal for collecting and processing information and a monitoring terminal located in the control center. Programmable logic controller (PLC) is the core component of remote terminal and monitoring terminal, which realizes data acquisition, analysis and processing. The remote connection and data transmission of the system are still realized by the transmission system. The software part includes the software applied to PLC and the software applied to monitoring terminal. The monitoring terminal software adopts visual graphical interface, which is intuitive, clear, simple, easy to operate, with detailed data records and easy to find.
1 1 conclusion
With the rapid development of urban rail transit construction and communication technology, various communication technologies and application methods applied to urban rail transit operation are also developing constantly, and many new technologies and modes have emerged to meet various application requirements. On the basis of analyzing the functional requirements of rail transit and combining with its own actual situation, the appropriate communication system mode is selected. Through the operation effect in recent years, the communication system has played an important role in improving operational efficiency and service level.
refer to
[1] GB 50458-2008, Code for Design of Straddle Monorail Traffic [S]. Beijing: China Building Industry Press, 2009.
[2] He, Wang Songzi, et al. Operation and maintenance of urban rail transit communication signal system [M]. Beijing: China Building Industry Press, 2007.
Xiao yajun, Wu. Communication Technology of Automatic Train Control System in Rail Transit [J]. Urban Rail Transit Research, 2002, (2):59.
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