Distribution Automation Communication System Based On Middle Voltage Power Line--Sub-station System

With the development of economy and rise in people's living standard, the demand for power increases more and more. The degree of that people are dependent on power becomes deeper and deeper. The quality and reliability of supplying power also become more and more important. However, middle voltage and low voltage power network structure in most areas is not reasonable. The equipments are out of date. Something wrong often happen. And the supply is not sufficient. The quality of power is not satisfied. The circumstances of breaking off often appear. For solving the mention above, we are proceeddmg city power network reform. City power network reform has two sides. One is that reforming city distribution network structure. The other one is that improving distribution system management level by realizing distribution automation. Only by reforming city power network and realizing distribution automation step by step, the improvement of the quality and reliability of supplying power could become true.Distribution automation is an integrated system that real-time keep an eye on, coordinate and control the equipments in distribution network. Developed countries have begun to realize distribution automation step by step. Distribution automation communication system is the foundation of realizing distribution automation. Only by developing a reliable, effective and economical distribution automation communication system, distribution network can realize automation completely.Because of the mentioned reason above, this paper studies distribution automation communication system based on middle voltage power line. Distribution automation communication system has many ways of communication. We choose the best of all- distribution line communication. After the characteristics of middle voltage power line are described, the paper introduces two possible solutions of high-speed data communication -spread-frequency modulation and OFDM. The paper analyses some MAC protocols too. To conclude, OFDM and CSMA/CA are fit for middle voltage distribution network by comparing with both advantages and disadvantages. Based on middle power line and using PowerPacket technology, the paper presents the design of sub-station of communication system to realize high-speed data communication. The cores of the design are INT51X1 of Intellon Co. and W90N740 of WINBOND Co. It runs sound in the middle voltage power line.