Design Of AMR System Of Low Voltage Power Line Based On OFDM

Automatic meter reading system on low voltage power line is composed of devices collecting the information of ammeter, channels and web servers. It collects low voltage power customer's information on power consumption, analyses and processes data using modern electronic technology, communication technology and computer technology. Automatic meter reading system decreases expense for electric power company and provides much more service for customers. Also it is the basis of smart grid. So the application and development of automatic meter reading system have a great significance for electric power companies, customers even all of the society. The study focuses on the following aspects:(1) This paper analyses the characteristics of power line channel such as impedance, fading and disturbance. And a simple model of low voltage power line has been established, which provides for simulation on communication technology.(2) A particular research on low voltage power line communication technology has been done. It is indicated by comparison that the main problem of narrow band technology applicated in power line carrier communication is that various noise and disturbance affect the communication qualitity, limited band restricts transfers speed; Then spread spectrum communication has excellent performance on anti-jamming and high transfers speed, but it goes against rare frequency resource, it is hard to improve transfers speed because low SNR in spread spectrum communication is attributed to spread bandwidth. However, orthogonal frequency division multiplexing(OFDM) could make full use of frequency bandwidth and improve the capability of anti-multi-path fading. An improved method is brought forward based on currently research in order to apply OFDM to power line carrier communication and it has been simulated by establishing Matlab model. It is indicated by the simulation result that reliable data transfers can be achieved under the situation of bad power line channel and high error code rate.(3) A deep research on implement of system has been done, including total scheme, software platform and hardware platform. Atme19260 is the core of hardware design of collecting device, and external extended-memory K5D5657ACB_D090 has been extended by EBI. Power system is composed of AC and DC, and several kinds of DC of different rank are provided for different circuits. Modularization is adopted in the design of circuits of power line carrier communication and remote wireless communication.(4) Communication tests on up and down channels are accomplished and the results prove that design of collecting device satisfies requirement in automatic meter reading system.Lastly, paper summarizes some harvest and significant meaning which is gained from the study. Also some difficult problems needed to be solved are brought up and a brief prospect has been done.