The Simulation Of Ethernet-based Substation Automation Communication Protocols

The Ethernet is used widely as the communication network of SAS with the development of computer technology and the communication network technology. However, the traditional Ethernet technology using the CSMA/CD protocols is a delay-non-deterministic network, even does not support the priority transmission. When the network loads oversizes, the communication performance reduces greatly. Therefore it is neccessary to thoroughly research the delay of the communication network of Ethernet- based SASThis paper introduces the protocol formats,the transmission rules and the application process of IEC60870-5-104 and IEC60870-5-103, analyzes the format of network-103 protocols ,and indicates that it is a better choice to use network-103 protocols when Ethernet is used in the bay layer network. Then, this paper studies the network structure, the data stream, the transimmission rules of message in the Ethernet-based SAS, obtains the factors that affecting the realtime of communication network., and simulates the sending prosses of the spontaneity message and loop messages by the EPOCHS .This thesis uses a method that synchronically simulates the traffic in a substation with the PSCAD/EMTDC simulator and the NS2 software ,and simulates the alarm messages closely related to the faults in the electric power system around substation . This thesis obtaines the results of link layer delay, message delay and network load etc., and quantitatively analyzes the factors affecting the communication network realtime transimission ability through setting different the network environment and parameters.