Analysis of Multi-network integration mode of ATM-Based Power Communication Networks

Due to historical reasons and the special nature of the industry, the electric power system and the railway, civil aviation, petrochemical and other departments all have their own large-scale communication networks. Due to the wide variety of communication network services and independent business, the power system formed a situation where multiple networks operated in parallel within a certain period of time. With the continuous development of the industry, the demand for communication in the power system is also increasing. In addition to voice, data, fax and other communication services, the exchange and transmission of broadband data such as images are also increasing. Some new terminal devices are widely used, which puts forward higher requirements on the transmission capacity, speed and bandwidth of the power network. On the other hand, due to the rapid development of basic technologies, especially the development of microelectronics, optical communication, Internet and ATM and software technologies, it has had a profound impact on the development of communication networks in the power industry. In this context, the power communication network is rapidly developing towards Digitalization, integration, and broadband.
Previously, the communication networks of Power Enterprises designed several independent networks based on different specific services such as administrative communication, scheduling communication, and data communication, one of these networks is often unable to fully adapt to other services. The consequence of these service network specializations is that multiple independent networks coexist, and each network needs to be ordered and maintained by the enterprise, even if a network has
Idle resources cannot be used by other types of services. Recently, the Datang power grid directly affiliated to China North Electric Power Corporation includes Beijing, Zhangjiakou, Chengde, Langfang, Tangshan, Qinhuangdao, and other power supply/power companies) we are establishing a digital broadband integrated service network with ATM switch as the core technology. ATM has a variety of comprehensive capabilities, including comprehensive business calls.
Sound, data and images), network integration from desktop, LAN to Wan) and technology integrated transmission, reuse, cross-connection and exchange ), it integrates the features of circuit switching and group switching and provides end-to-end connectivity to ensure the quality of service (QoS) for voice, data, images, and multimedia information transmission ), it also provides comprehensive traffic control and congestion control, Flexible Dynamic Bandwidth Allocation and Management, strong self-healing ability, and security. Although the structure of ATM is complex and expensive, it can integrate all telecommunication services, including voice, data and images, and implement it to the desktop. Based on these advantages and the special requirements for communication reliability based on the characteristics of the power system industry, the ATM Integrated Service Network has become the development direction of the Power Communication Network. With the establishment of the ATM network, the "N-network integration" trend of the power enterprise communication network is becoming more and more obvious. The ATM network will change from business integration to network integration, and is gradually becoming a unified transmission platform of the power communication network.

I. Business overview of China North Electric Power Group tongtang Communication Network
In the production and infrastructure of China North power grid, there are several communication businesses that coexist: administrative telephone system, power dispatching communication system, integrated communication monitoring system, information center business, lightning monitoring system, conference and television system, and EMS computer system. The following describes the functions, status quo, and features of these systems based on the actual situation of Zhangjiakou Power Supply Company.
1. China North Electric Power administrative communication exchange network
China North power system administrative communication exchange Network (CEN) is a Shijiazhuang Ministry of Information Industry 54th HARRIS20-20LH/LX Type Digital Control Switch Based on the exchange node composed of the coverage of North China Composite Network, is a part of the special communication network of North China Power System, it is also a Backup Communication operator for North China Power Dispatching.
. It supports communication between users of tongtang power grid, including working users and residents. The network adopts a tree structure and is networked based on administrative and geographical relations. In the tree structure, a small number of direct routes are provided based on business needs and channel conditions. The settlement center is located in China North Electric Power Corporation, and one or two regional settlement centers are located in each region. Regional settlement centers are generally located in regional power supply/power supply companies and power generation plants. The North China junction centers and their subordinate areas are developing towards the hybrid network. Currently, inter-Bureau relay uses automatic connection. Generally, there are several 4WEM signaling channels, and a few are
2 Mbit/s. Each vswitch is connected to the Local PSTN Public Network Using several 2 Mbit/s PCM channels to become an End board or user switch of the public network. Inter-office relay adopts automatic connection, while BID + DOD2 or DID + DOD1 is used for public networks. The signaling mode mainly adopts the same-path signaling, while the existing ISDN function is the same-channel signaling. The Backbone Routing is set up step by step from the receiving center to the end station, and the exchange station establishes a direct or efficient route for low call loss based on the traffic volume. The route selection sequence is from bottom-up in the sending swap area, from top to bottom in the SWAp area, and from far and near in the whole network. First, select efficient direct route, and finally select the base dry route.
2. China North Electric Power Dispatching Network
China North Electric Power Dispatching Network is a communication network that carries the state-level, provincial, and regional power dispatching of China north. In the China North Electric Power Dispatching department, provincial dispatching agencies, regional dispatching centers, and important substations all have their communication nodes. The scheduling communication network of tongtang power grid is a composite network composed of more than 30 programmable digital dispatching machines (MD110) of Beijing zhaowei Group Corporation. Among them, power plants and power supply companies in various subordinate institutions have a central node in the control building and several nodes distributed in each substation. Considering the reliability requirements of scheduling operations, the network requirements are strict. Exchange nodes are connected through various channels, such as microwave, carrier, and optical fiber. Generally, administrative users are prohibited from accessing the nodes. There are several detour channels available between each two nodes. The relay channel is usually in the 4WEM mode and adopts intermittent Signaling connection.
3. Comprehensive Monitoring and Management Network for power systems
The network is an independent power Communication Management Network (PTMN) to achieve comprehensive management of communication equipment in the power system communication network. The Communication Management Network of tongtang power in North China is composed of monitoring subnets in Beijing, Zhangjiakou and Tangshan to form a wide area network. Each subnet consists of a central station and several workstations. This network center uses 100 Mbit/s Ethernet,
The WindowsNT4.0 operating system and TCP/IP protocol are interconnected with the wide area network for comprehensive monitoring and enterprise network or ATM switch of the Power System Communication Network in North China. It is scalable and flexible, and the application software and interface equipment are standardized and modular. The workstation collects data in real time, processes the level, voltage, temperature, smoke, anti-theft, and other telemetry values of the devices and environments of each communication station, and sets the threshold value, and historical databases in the distribution mode are stored in various historical information for reference for a long time. Client/Server C/S) or browser/server B/S.
As a private network for monitoring, controlling, and managing the communication network of the power system, the communication network monitoring system monitors transmission devices, exchange devices, user devices, and other related devices in real time, and can communicate with other networks to achieve data sharing.
4. Information Center System
The information center system of Zhangjiakou Power Supply Company uses the SYSTEM5000 of BAY as the main switch and the ALPHA2100 minicomputer of DEC as the main server. With the performance provided by this network, you can easily establish an enterprise intranet and access the Internet as a user of the North China Bureau Wan. This fast-switching Ethernet is dominated by the scheduling building and the connection package
Multiple LAN points, including the substation work area, power distribution business office, multi-Longitude office, and line work area, are connected to the computer networks of the publicity office, lower office, County Power Supply Company, and North China Power Group Company through microwave, A scheduling building-centered wide area network is formed. The scheduling building itself is a LAN on the 17th floor. Each room in the building has three sites, totaling 492 sites and 80 sites.
, And. Running the Management Information System ZGMIS on this network ), it includes more than a dozen subsystems, including planning, integrated query, production technology, production and operation, finance, electricity, labor, security supervision, infrastructure, materials, and scheduling SCADA interfaces. In addition, in terms of office automation, IBM's lotus notes cluster is used to implement functions such as transaction processing, Information Publishing, information query, document flow grading, conference management, email, and information editing. Lotus notes can also be connected to large databases for data sharing and smart processing.
5. Lightning Monitoring System
Lightning Monitoring System (LLS) is a system that monitors lightning activity in real time. It consists of three parts: the direction time difference detector (DTF), the central processor (NPA), and the lightning information analysis and display terminal (LIADS. It can measure parameters such as the time, location, amplitude, polarity, and number of return attacks of lightning in real time, providing a large amount of practical data for lightning protection, it also provides convenience for Quick Searching for lightning fault points of transmission lines. LIADS is one of the three components of the lightning positioning system. It is a lightning analysis and display terminal composed of a computer hardware and a dedicated LIADS software, it mainly displays the lightning point position and the running track of thunderstorms, and analyzes and collects lightning information. Such as real-time display of lightning information, replay display of historical information, target database editing and fault query. After receiving the lightning signal from the central processor NPA, LIADS converts it into computer screen coordinate based on the longitude and latitude of lightning through a series of transformations, calculations, and processing,
The lightning strike points and lightning parameters are located at the corresponding positions on the screen map, where the color electronic map is transferred to the memory after the program is started ).
LIADS can be put together as a local terminal and NPA, or as a remote display terminal to stay away from NPA. In this case, the communication channel between LIADS and NPA must be established. Lightning analysis shows that the communication of the terminal adopts asynchronous serial duplex leased line. The signal sent from NPA is sent to the serial port of the computer by the modem. It adopts ASCII code, 1-bit start bit, 8-Bit Data bit, no parity check, and the baud rate is between-, depending on the communication mode.
6. Conference and television
Conference television is a form of opening a meeting for remote participants in a virtual conference venue based on the ample bandwidth capacity of communication transmission channels in the power system and the wide regional distribution of the power system. Video and audio collection systems and high-speed broadband transmission are used to send and receive audio and video signals of participants distributed in different venues in real time.
Efficient information transmission and interaction. Audio and video signals are collected, quantified, encoded, compressed, and finally imported into the channel.
II. Introduction of various upper-layer services integrated in the underlying basic network transmission mode
1. Administrative telephone business
The remote control switch uses the 2ME1 interface and cas dtmf or etsi qsig signaling to connect to the E1MVP board of the ATM switch to realize the SVC connection of the voice. For R2DTMF and ISDN Q-SIG signaling, the SVC method can be used to achieve the voice connection of the Administrative phone.
2. Electricity Dispatching Network
In view of the importance and particularity of the Power Dispatching Network in Power Grid production, it must be smooth, non-blocking, and stable. Therefore, it cannot be fully translated into the ATM mode for the time being. After the experiment is completed, the ATM channel is used as its standby communication means to enhance its security and reliability and achieve safe production and scheduling of electricity.
3. Integrated Communication Monitoring System
For the communication Comprehensive Monitoring Service, the PASSPORTATM switch will be automatically connected to the new building of China North dispatching bureau in the central point in 10/100 Mbit/s mode, on other sites, the four-port E1C board of the ATM switch is connected through the router E1, And the PPP protocol is used. The OSPF protocol is used, and the business access mode is the same as the information center access mode.
4. Information Center Business Access Method
In the previous information center, the existing routers were used to achieve computer connection with power supply companies and power plants in different regions in the form of 2 Mbit/s or 64 Kbit/s, the new system uses the 10 Mbit/s/100 Mbit/s interface and OSPF protocol to access the PASSPORTATM Switches of each ATM switching node.
5. Lightning Monitoring System
Currently, this service uses a point-to-point structure. The PC terminals of the dispatching offices of various power supply companies access PCM through modem ansync. After the new system is installed, the original PCM Interface accesses the ATM network through the 2 M E1 CES port.
6. Conference and television
The conference and television business will adopt the H.320 standard and access the ATM switch through the E1 interface, which is implemented in the form of BTDS. Currently, the EMS computer system is only available in Beijing, Tangshan, and Tianjin. After the ATM switch system is established, the E1G703 interface is provided by the switch, using the CISCO router and using the IP protocol, RIP Protocol. The service access method is the same as the information center access method.
In the "China North tongtang Electric Power Digital Data Communication Network", the priority of all businesses is as follows: scheduling program-controlled exchange; scheduling EMS automatic information and computer system; electricity Market and marketing system; Administrative telephone; Conference television; integrated communication monitoring system; lightning monitoring and positioning system; Integrated Management MIS System and other MIS system.
Powered by the stability and superiority of its own equipment, the power system has continued to develop and become increasingly advanced, reliable and mature communication technology in recent years, A solid, solid, and reliable broadband communication network has been developed for its own communication business architecture. The integration of "bottom layer" transmission has basically formed various business separation, which laid a solid foundation for the rational use of resources and both reliability and stability. Communication in the power system plays an important role in the system. It is the material basis for automation and modernization of the power system. It has made great contributions to safety production, economic scheduling, and infrastructure construction. With the development of the situation, the communication of the power system is not only based on the service of the system, but also to fully grasp the potential of users outside the system, take a step of industrialization. From this point of view, the power communication field should seize the opportunity to improve and develop itself more quickly.