Study Of Digital Substation Communication Simulation And Network Reliability

IEC 61850 protocol provided a direct reference to realize network construction of digital substation. This paper presents the IEC 61850 standard architecture and modeling process of substation automation system applying IEC 61850.Substation functions are achieced by logic nodes and logic devices defined by IEC 61850,while adopting PICOM to describe information enchange between logic devices.IEC 61850 defined ASCI to describe external communication performance and SCSM to mapping communication service to protocol stack.Substation automation executed by switch network is divided into three levels by IEC61850 protocol:station level,bay level and process level. Network structure could be divided into two modes in logic:the mode of combining station bus and process bus,the mode of the independent process bus.Three kinds of network structure could be used in digital substation:bus,star and ring topology. Considering the reliability,redundancy of the network is necessary.This paper analyzed several redundant structures and improved forms applying the existing protocols.A communication network structure of three-level digitized substation based on HSR was presented.In allusion to two kinds of real-time messages(SAV and GOOSE),the models of typical data flows in substation network were built. This paper constructed IED nodes in OPNET modeling,end-to-end time delay and delay fluctuation of SAV and GOOSE were simulated under different substation types(T1-1 and D2-1).Broadcast and muticast messages would be confined in their necessary parts of the network by organizing VLAN,and message transmission conflicts in switchs would be reduced which improved the real-time performance of the networkAccording to reliability requirement, this paper analysised the reliability of digital substation communication network. Reliability block diagrams were established under different network structures.Under the consideration of the reliability function of each part of the network.reliability indexs were obtained and compared.with different network structures.