The report of the 16th National Congress of the Communist Party of China pointed out: Informatization is an inevitable choice for China to accelerate industrialization and modernization. Insist on promoting industrialization with informatization and promoting informatization with industrialization, and embark on a new way of industrialization with high technological content, good economic benefits, low resource consumption, less environmental pollution, and full advantage of human resources. An industrial pattern with a high-tech industry as the guide, basic industries and manufacturing as the support, and a comprehensive development of the service industry will be formed. The power industry also needs to be informatized, and the energy meter data collection system is a good application. Due to technical and economic constraints, the existing energy meter collection meter reading mode also has harmonic interference problems such as 220V low-voltage power grids; manual problems with handheld infrared meter reading; self-built network costs and maintenance issues; telecommunications and telephone Tariff issues; wireless network transmission quality and rate issues, etc. In order to find a communication method that can better solve these problems, we turned our attention to the broadband network. In recent years, with the rapid development of global informatization and information digitization, China has invested huge manpower and material resources in the information industry, and has proposed the goal of "Gigabit to the community, 100 trillion to the floor, and 10 trillion to the family", and Has achieved gratifying results. In order to build a "digital information port", many cities and regions are spending huge sums of money to strengthen the construction of network infrastructure based on IP technology, and have solved the "last mile" access problem, in order to build applications that meet different needs on the network The service and the cultivation of a good e-commerce market environment have laid a solid foundation. Therefore, the full use of fast, reliable, maintenance-free, relatively cheap, and gradually reduced public wired networks to transmit energy meter information is one of the future development of energy meter collection. The megatrend is also an important part of the value-added services in the urban information port plan. 2. Working principle of network centralized meter reading system The network centralized copying system is composed of data collection equipment, data Internet access equipment, broadband network and main copying station (including front-end software and back-end database). Among them, the data collection device is also the collection terminal, which can not only collect the pulse output of the pulse electronic meter and convert it into the energy meter data, but also collect the data output by the multi-function meter through the 485 port. The data Internet access device refers to a network communication server or an IP server, which has the function of packaging the data sent from the collection terminal into a data packet conforming to the relevant network protocol and performing bidirectional transmission. The broadband network has the function of transmitting data between the computer of the master station and the energy meter. The network monitor has the functions of monitoring the operation of the system, determining the fault point, and dividing the maintenance responsibilities; the network terminal hub is the network operator (Internet Service Provider (ISP for short) is the terminal equipment in each residential building unit, through which the communication server accesses the broadband network. The master station has the function of processing various data and connecting with the billing system. The working principle and data flow of the network collective reading system are shown in Figure 1. The collection terminal processes and stores the collected energy meter data, waits for the background timing or issues commands at any time, and sends the data to the network communication server. Table master station. The meter reading master station performs simple statistical calculations on the collected data for the meter reading specialist to make preliminary analysis and judgment, and finally sends the data to the electricity billing system. It can be seen that the network meter reading system can complete the meter reading and billing work in a large area or even the whole city in a short time. At the same time, periodic collection and random collection can be set for key enterprises or users who need to monitor to meet the monitoring needs. It is worth mentioning that in areas where network collection is required, if the collection terminal cannot access the Internet nearby, a "high-speed PLC" system can also be used to solve the "last mile" access problem. PLC, or Power Line Communication Technology, refers to a communication method that uses power lines to transmit data and voice signals. "High-speed PLC" system is composed of PLC modem, PLC router and repeater, etc. The transmission rate of these devices can reach 2 ~ 45Mbps. The role of PLC modem is similar to ordinary MODEM. It is responsible for packaging and transmitting the data sent from the collection terminal to the power line. The PLC router is installed beside the distribution transformer and is responsible for collecting the data sent by the PLC modem on each phase distribution line, and then sending the data to the Internet through high-speed communication means such as optical fiber. When the communication distance between the PLC modem and the PLC router exceeds 300 meters, a repeater can also be used to amplify the transmitted data. 3. Security measures in the network centralized meter reading system The normal operation of the network copying system requires the following conditions: (1) Rich IP address resources, such as: community local area network or public network VPN, etc .; (2) Can prevent illegal activities of various professional intruders; (3) Timely and automatically identify the fault point of the system and determine the faulty equipment. To this end, the network collective reading system has taken different measures in three aspects of data collection terminal, network communication server and broadband network to ensure its own safe operation. 1. Data collection terminal The data storage and transmission in the data collection terminal adopts special encoding rules. Since the encoding rules are kept secret from the outside and are the industry's internal secrets, an attacker cannot recover the stolen data without knowing the encoding rules. Industry secrets. Attackers cannot recover the stolen data without knowing the encoding rules. 2. Network communication server With the rapid development of network technology, the Internet has penetrated into thousands of households, especially with the continuous expansion of the scale of broadband networks, low-cost equipment access to the Internet has become a trend, these are all popularization including network centralized meter reading Similar network applications have created conditions. The communication server solves the communication problem of ordinary serial devices on the Internet / Intranet by converting serial data such as RS232 / 485/422 into data packets conforming to the TCP / IP protocol. The communication server generally has a 10 Mbps Ethernet interface, which can be directly connected to the Ethernet; one or more RS232 serial interfaces can be expanded to other forms of serial ports such as RS485 for connecting terminal devices. The security measures of the network communication server include: (1) Specially designed data transmission protocol: There is a special data communication protocol in the server. Since the attacker cannot know the details of the protocol, it is difficult to attack from the protocol side. (2) Data encryption mechanism: Based on the proprietary communication protocol, the server encrypts the transmitted data at the same time. It is difficult for an attacker to obtain plain text data without knowing the encryption algorithm and encryption password. (3) Password authentication mechanism: A password authentication mechanism is designed in the server, and all password transmission adopts ciphertext transmission, which fully guarantees the system security. 3. Virtual Private Network (VPN) In order to make full use of network resources, obtain economical and flexible networking methods, and save users' investment in equipment, personnel, and management, the network centralized meter reading system adopts an MPLS-based VPN solution. Virtual private network (Virtual Private Network, referred to as VPN) is a service that network operators use the resources of the public network to form a private network for customers. VPN has two meanings: First, it is a virtual network, that is, there is no fixed physical connection, and the network is only established when users need it; Second, it is a private network composed of public network facilities. VPN combines many features of public network and private network. It combines the reliable performance and rich functions of public network with the flexibility and efficiency of private network. It is a network between public network and private network. MPLS (Multiprotocol Label Switching) is multi-protocol label switching, which belongs to the third layer switching technology based on the label mechanism. MPLS separates routing and forwarding, and the label specifies the path of a packet through the network. In the MPLS network, the data packet does not follow the IP header, but is forwarded by switching labels; when the data packet is to exit the MPLS network, the data packet is unencapsulated and continues to reach the destination according to the routing of the IP packet Ground. The node at the edge of the network is called the label edge router (LER), and the core node of the network is called the label switching router (LSR). The LER node completes the IP packet entry and exit process in the MPLS network, and the LSR node provides high-speed switching functions in the network. The path between MPLS nodes is the label switched path (LSP). An LSP can be regarded as a unidirectional tunnel running through the network. The MPLS-based VPN used in the network collection system can ensure the security of the network through BGP (Border Gateway Protocol) technology. BGP is a routing information distribution protocol that specifies the protocols and attributes of communication between network nodes. The VPN member attributes are determined by the logical port number that enters the VPN and the unique RD (Route Distinguisher) assigned to each VPN. The end user does not know the value of RD and can only participate in VPN communication through a predefined port. In MPLS-based VPNs, BGP only exchanges FIB (Forwarding Information Base) table updates between LSRs that have updated VPN sites. This ensures that each LSR only saves its own FIB table and VPN information. Since each user's logical port determines his RD, and this RD is uniquely associated with a VPN when the VPN is defined, the user can only access the VPN associated with him, that is, he can only realize this VPN The presence. Since each VPN defines a unique RD, combining each RD with the IP address of the VPN is unique to each node. The entry information of the VPN IP address is stored in the FIB of the VPN-related node, and the VPN IP forwarding table contains a mark corresponding to the VPN address. These tags route traffic to the node it should go to. Because the tag replaces the IP address, users do not need to use the address provided by NAT (Net Address Translation) or ISP, but keep their own private address. Due to the use of RD and BGP to realize the interconnection of VPNs, there is no awareness of the existence of other VPNs between different VPNs. If you need to connect to Extranet VPN, you only need to define the trust relationship between the two VPNs through RD. Not only that, MPLS also supports firewall technology and high application encryption. It can be seen that MPLS VPN mainly relies on core software technology to ensure network security. It provides routing information distribution restrictions and MD5 routing authentication technology, so that the public network on which users rely can become a trusted network. For security reasons, proper access control can be done between PE (network operator edge router) and CE (user edge router): CE can not allow from PE Telnet to CE router, that is, user-side data can be completely accessed by users The side itself performs maintenance processing; at the same time, the PE at the central office also does not allow CE Telnet to the PE router. 4. Common problems in the network centralized meter reading system 1. Interconnection of internal network of power supply bureau with external network: As mentioned above, the main station of the centralized meter reading system of the power supply bureau uses the VPN provided by the ISP as the channel for remote automatic meter reading, so it is connected to the external network of the power supply bureau. At the same time, the main meter reading station also needs to exchange data with the electricity business system database of the power supply bureau and provide a data source for the relevant departments of the power supply bureau to browse the meter reading information. Because the internal network and the external network have different requirements for the configuration of the network adapter (ie, the network card), if the main station computer has only one network card, the master station software communicates with the collection terminal of the external network or uses electricity with the internal network. Between the data exchange of the business system database, the properties of the network card need to be changed, and even the computer needs to be restarted for the Win98 operating system. To solve this problem, a relatively simple and low-investment method is to install two network cards for the main station computer, which are respectively connected to the internal network and the external network of the power supply bureau. For the network card connected to the internal network, the IP address, subnet mask, default gateway and other attributes should be configured according to the requirements of the power supply company's internal network; the network card connected to the external network must be configured according to the IP attributes provided by the ISP . In order to ensure the security of their local area networks, most power supply bureaus generally require the physical separation of the enterprise's internal and external networks. To this end, after the communication between the main station computer and the external network acquisition terminal is completed, the external network cable is unplugged to achieve physical isolation of the internal and external networks of the power supply bureau. 2. VPN interconnection of multiple network operators: When the collection terminals of the network collection are distributed in the networks of different ISPs, in order to communicate with these collection terminals, the power collection bureau collection collection master station should also be located in the same VPN as these collection terminals. Therefore, first, each relevant ISP should lay a line to the power supply bureau, and connect to the power supply bureau's switch via a router to ensure that the power supply bureau master station is physically located in each network. Secondly, on the routers connected to each network company, the IP address of the MAN port is set to the VPN IP address given by the network company, and the IP address of the LAN port of the power supply bureau is set to the internal network segment address of the power supply bureau. In this way, the power supply bureau master copy station can copy and collect the collection terminals in the VPN through different VPNs of different ISPs. And there is no awareness of the existence of other VPNs between these VPNs, that is, a seamless connection can be achieved. Figure 2 shows the situation where the power supply bureau master station is connected to two network companies, and many network companies can do the same. When only one VPN provided by an ISP is used, only one router can be used. This is also a relatively complicated and investment-intensive method for solving the problem of connecting the power supply bureau's internal network and external network. V. Conclusion The network centralized meter reading system, as a remote automatic meter reading system with broadband network as the channel, has the following characteristics: (1) Objective. To realize the automation of centralized meter reading, the energy meter data is directly transmitted to the main meter reading station of the power supply bureau through the broadband network, and sent to its electricity business system through the power supply bureau's local area network, and the electricity bills are output in time, completely eliminating the human factor. (2) Strong real-time performance. The Meter Reading Specialist of the Power Supply Bureau can click to inquire about the power consumption of any user (resident or enterprise) at any time, providing the possibility of conducting power inspections or developing remote control systems. (3) Fast and accurate. Compared with the other meter reading systems of electric energy meters, the network copying system has a fast copying speed and high data accuracy. After on-site testing, the network collection system only needs about one minute to complete the data collection of 300 meters at a time, and the collected data is completely correct after comparison. (4) Low cost and easy management. Using the energy meter network centralized reading system, the power supply bureau is only responsible for the management and maintenance of the meter reading master station and the collection terminal, and the operation management of the communication channel, that is, the broadband network, can be completely handed over to the ISP. Therefore, the power supply bureau acts as the broadband network. Users can maximize the benefits of professional management. (5) Easy to promote. There are not too many resources required to realize the power network collection. It is generally applicable in large and medium-sized cities and county-level electric power bureaus in developed regions. (6) Significant. As a result of remote automatic meter reading, it can improve the work efficiency of the enterprise, enhance the enterprise's technology, management level and establish a new image of the enterprise. It can be seen that the use of a network centralized meter reading system is a thing that benefits the power supply bureau, network operators, and the general public. Therefore, it has aroused great concern and strong interest from all parties concerned. The Communication Research Institute of the China Electric Power Research Institute has followed this trend of informatization development. To meet the needs of the market, it has developed a network meter reading system for electric energy meters, which has now been put into operation in some residential areas of Ningbo and Hangzhou in Zhejiang Province. . With the active cooperation of local power supply bureaus and network operators, the system is currently operating in good condition. It is foreseeable that the network meter reading system of electric energy meters will become the mainstream of automatic meter reading products in the distant future.
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Figure 1. Working principle of network centralized meter reading system 
Figure 2. VPN interconnection between power supply bureau master station and ISP 
October 29, 2020