Research Of Communication In Digital Substations Based On IEC61850

Digital Substation has become the development trend of Substation Automation Systems. Emergence of smart equipments such as ECT/EVT, intelligent switchgear and etc. make deployment of Digital Substations possible. Fast, reliable and open communication networks as well as comprehensive communication standards ensure the implement of Digital Substations, especially the new distributed international standard of substation communication network and system EEC61850 provides complete criterion for construction of digital substations.This paper first analyzes the major technical indicators of IEC 61850 and describes several typical realization methods of communication service. Then based on characteristics of digital substation, taking D2 substation of IEC61850 standard as the example, several different network construction or network building schemes for digital substation are presented. The message types of substation communication are also analyzed.Based on the D2 digital substation model of IEC61850 and the actual situation of digital substations, this paper analyzes advantages and disadvantages of unicast, multicast and broadcast and adopts multicast as the transmission model of digital substations. Then this paper discusses several widely used methods for improvement of real-time processing in Ethernet network: changing network topology, adopting switched ethernet and priority tag, as well as improving real-time communication models and etc. According to the characteristics of digital substations, this paper proposes to carry out message priority transmission control simultaneously in node network and switch to improve real-time processing.Finally, this paper taking D2 substation of IEC 61850 as an example, simulates in OPNET. Simulation results show that our proposed method can considerably improve the communication performance of digital substations that meet the requirements of IEC61850. It achieves the time indicators of IEC 61850. The research is valuable for improvements of real-time processing in communication networks of new type digital substations which are networked with Ethernet model.