Research On Substation Automation Network Communication System Based On Ethernet

The development of substation automation brings some new demands on its communication network. The most important thing is that the new and high-powered communication network is used to meet the demand of technology progress. Due to its low speed and multiple standards, the Fieldbus hardly comes up with the requirement. Ethernet has become the preferred network solution for the industry control network because of its ubiquitous application, low cost, high speed and abundant software and hardware resources. The trend of new substation automation is that Ethernet will be used for process bus and station bus in substation.As for Ethernet, the mechanism of CSMA/CD (Carrier Sense Multiple Access/Collision Detection) is used in media access control. This mechanism has unforeseen delay characteristic, so the transmission on network is not determinable, especially when the network load is so large, the real-time performance decreases greatly. At the same time, reliability, usability and security of Ethernet are not applicable fully in substation circumstance.In this paper, the development and application of industrial Ethernet are discussed. The factors that influencing the real-time performance of Ethernet are studied based on profound analysis of basic principle and the concepts of message transmission of Ethernet through simulation. The characteristics of data flow in communication system of digital substation automation network and the requirements of communication network are analyzed based on IEC61850. A scheme with RTPS (Real-Time Publish /Subscribe) model is presented, based on which the key technologies for the realization of message transmission reliability and priority are researched. A simulation model of Ethernet is founded based on the communication scheme. A research on the substation communication network performance is carried out on the model, which will help to choose the network parameters, improve the transporting capacity and raise the property of substation automation. The researching result is valuable for communication design of the new substation automation based on Ethernet. Some problems are put forward for further study.