Current situation and Prospect of automatic meter

Abstract: This paper briefly describes the background of automatic meter reading technology for electric energy measurement, introduces the structure and characteristics of automatic meter reading system for electric energy measurement, expounds the current situation of automatic meter reading technology for electric energy measurement from the aspects of electric energy meter, collector and concentrator, as well as communication channel, and points out the application of automatic meter reading technology for electric energy measurement in power line carrier communication, wireless spread spectrum communication The research hotspot and development direction of the security of composite communication and automatic meter reading

key words: electric energy measurement automatic meter reading channel acquisition terminal electric energy measurement is an important link in the modern power marketing system. Traditional electricity 1. For ordinary metal and non-metal samples, the jaws of the fixture directly contact with the samples. Energy settlement depends on manual regular on-site reading data, which is insufficient in real-time, accuracy and applicability. Customers who use electricity not only require electricity, but also high-quality electricity to enjoy better service. Therefore, it has become the consensus of all power departments to improve the real-time settlement level of electricity charges and establish a new meter reading method. In addition, the power supply department also puts forward higher requirements for anti stealing technology. The automatic meter reading system of electric energy measurement is a system that automatically collects, transmits and processes electric energy measurement data. It overcomes the low efficiency and uncertainty of the traditional manual meter reading mode, and promotes the development process of the modernization of power management. 1 Composition and characteristics of automatic meter reading system for electric energy measurement typical automatic meter reading system for electric energy measurement is mainly composed of front-end acquisition subsystem, communication subsystem and central processing subsystem, as shown in Figure 1. 1.1 the front-end acquisition subsystem can be divided into local automatic meter reading system and remote automatic meter reading system according to different data acquisition methods. The electric energy meter of the local automatic meter reading system is generally equipped with an infrared conversion device to convert the electric quantity into an infrared signal. When reading the meter, the operator goes to the site to use a portable meter reading microcomputer to read the data contactlessly. The remote automatic meter reading system consists of an electronic watt hour meter or an electromechanical pulse watt hour meter equipped with a photoelectric converter, which transmits the user's power consumption to the upper level data acquisition device in the form of electric pulses. At present, most of the practical remote automatic meter reading systems use a two-level data collection structure, that is, the collector installed in the user's living quarter unit collects the readings of more than a dozen or dozens of electric energy meters, while the concentrator installed under the distribution transformer is responsible for reading data from the collector regularly. 1.2 communication subsystem communication subsystem is the channel that transmits data to the control center. In order to adapt to different environmental conditions and cost requirements, there are many schemes for the composition of the communication subsystem. According to the different communication media, the communication subsystem mainly includes optical fiber transmission, wireless transmission, line transmission and low-voltage power line carrier transmission. Optical fiber communication has the characteristics of wide frequency band, high transmission rate, long transmission distance and strong anti-interference, which is suitable for the requirements of upper layer communication. However, due to its limited installation structure and high cost, it is rarely used in automatic meter reading system. Wireless communication is suitable for occasions where users are scattered and have a wide range, and wireless communication is carried out by scattering communication at a certain frequency point. Its advantages are wide transmission band, large communication capacity (it can communicate with thousands of watt hour meters) and long communication distance (dozens of kilometers, which can also be extended through relay stations). At present, GPRS wireless communication network provides an efficient, convenient and reliable data channel for the implementation of wireless meter reading system. The main disadvantage is that you need to apply for the right to use frequency points, and if the frequency point selection is unreasonable, adjacent channels will interfere with each other. Leased line communication uses the network to install modems at the sending and receiving ends of data. This method has high data transmission rate, good reliability and low investment; The disadvantage is that the line communication time is long (usually a few seconds or even dozens of seconds). Low voltage power line carrier communication uses low voltage power line as the data transmission channel of the front end of the system. Its basic principle is: when sending data, the data is first modulated to the high-frequency carrier wave, and then coupled to the power line after power amplification. This high-frequency signal is transmitted to the logical receiver of the experiment designed by the assumption through the power line. The receiver separates the high-frequency signal through the coupling circuit, filters out the interference signal, amplifies it, and then restores it to binary digital signal through the demodulation circuit. The power line carrier directly uses the distribution network, avoids the problems of renting lines or occupying frequency bands, reduces the cost of meter reading, is conducive to operation and management, and has a very broad development prospect. However, how to suppress the interference on the power line and improve the reliability of communication is still an urgent problem to be solved. 1.3 central processing subsystem the central processing subsystem mainly develops the use of materials in different fields, which is composed of central processing workstation and corresponding software. It is the top layer of the entire electric energy measurement automatic meter reading system. The power consumption information of all users is gathered here through channels. Managers use software to summarize and analyze data and make corresponding decisions. If the hardware allows, it can also directly send instructions to the lower concentrator or watt hour meter, so as to control the power consumption behavior of users, such as remote operation of power shutdown and transmission. 2 current situation of automatic meter reading technology of electric energy measurement 2.1 the development of sensor, automatic instrument and integrated circuit technology of electric energy meter makes both electromechanical pulse type and electronic electric energy meter better meet the needs of automatic meter reading technology of electric energy measurement today. It is expected that the terminal acquisition devices of the automatic meter reading system for electric energy measurement will be mainly electromechanical pulse watt hour meters and electronic watt hour meters for a considerable period of time in the future. 2.2 collector and concentrator collector and concentrator are devices that collect the electric quantity data of electric energy meter. They are composed of single chip microcomputer, memory and interface circuit. Now more mature products have appeared. 2.3 communication channel communication subsystem is the key of automatic meter reading technology of electric energy measurement. The selection of data communication mode should comprehensively consider the characteristics of geographical environment, users' electricity consumption behavior, technical level, management system, investment cost and other factors. At home and abroad, there are different emphasis on different communication methods. In western developed countries, the research on software measurement and control system and computer for the re shutdown of automatic meter reading technology of electric energy measurement started earlier. The power system includes