Research And Implementation Of Network And Protocol Of Distribution Line Carrier Communication

In electric power communication network, the power line carrier communication is one of the important means. Especially in medium voltage distribution network, carrier communication has become one of predominate communication modes because of its exceptional advantage, and it is also widely used in power distribution automatic system and load control system. Traditional power line carrier communication equipment only provides the transparent data transmission channel. Therefore it can not guarantee the assignment problem and accuracy of data transmission channel. Based on the above, this paper studies communication architecture which is applied to distribution network.Distribution power line carrier communication technology is such a technology which uses the existing power distribution networks as the transmission medium to make information transfer and exchange come true, and which has some advantages, such as, quick effect, high reliability, high stability, low operating cost and less investment. At present, it develops very fast. The distribution line carrier technology which is the use of 10 kV distribution line has a very good application. However, as its requirement of high reliability and real-time, the main task of the paper is to researchand develop a set of efficient communication protocol to improve the performance of the whole system.According to the international standard "IEC61334 distribution automation using distribution line carrier systems", this paper simplifies the communication model into three layers: the physical layer, data link layer and application layer. According to the internal structure of the distribution network(chain network, tree network and loop network) and the data transmission technology, this paper divides distribution network into two categories: point to point and point to multipoint network, and designs two kinds of model of the communication protocol. The first is point to point communication protocol design for data transmission protocol a stop and wait, automatic retransmission. The second is point to multipoint communication network which is very complicated and difficult to realize. The key is to solve how to ensure the transmission of real-time data in the processing of channel conflict. This paper uses three solutions: polling, based on collision avoidance and collision detection based on virtual carrier. The first scheme is simple, and it can guarantee the real-time. The disadvantage is low efficiency, and it can not fundamentally solve the problem. The other two schemes are relatively flexible, which can effectively utilize the channel and also can improve the efficiency of data transmission, but it is difficult to realize.Different system architectures also have great influence on the overall performance of this system. In the fifth chapter, the design idea and technical scheme of the system architecture are introduced in detail. Distribution line carrier communication system designed in this project works well in the laboratory. The whole system has high real-time, high reliability and high flexibility, and can meet the requirements of the distribution line carrier communication development.