Study Of Digital Substation Network Structure

Substation is an important node of power system, it plays an important role for thedistribution of electricity. Ensuring the safe and stable operation of substation, which is avery important role in maintaining power system stability.Automation system of substation,as the core part of substation, how to ensure the performance of continuous improvementto adapt to the rapid development of the power system, has becoming more and moreimportant. At present, substation automation system has realized the protection function ofthe independent and parts of the information sharing.However, there are still someproblems existing in Substation Automation System, for example the automation functionis independent, lacking of interoperability; the using of information is inefficient; and thesecondary connection is complex, and so on. The IEC61850standant which is the latestand the most authoritative communication standard, provided a direct reference to realizethe Substation Automation System.This paper firstly introduces the contents and technical features of IEC61850standard.Then introduces the types and the features of the message. And then analyses theadvantages of digital substation: data acquisition digital, hierarchical and distributedsystem structure, system structure compact, equipment modeling unification, informationnetworked, information application integration, equipment maintenance, equipmentoperation state of intelligent.The IEC61850standard divides the substation automation system into three layerstructure from the physical structure: the process layer, bay layer and station layer. Fromthe logic structure it has been divided into two networks: process layer network and stationlayer network.According to the characteristics of substation communication structure, based on IEC61850standard, studied IEC61850standard the process layer network: position oriented mode, single bus mode and function oriented methods; and the station layer network bus:the total unified communication structure and the two network independentcommunication.At the same time, in order to ensure the reliability of communicationnetwork of digital substation, the redundancy of the network is necessary. After introducingthree network topology structure: bus type, star type and ring type and analysing theiradvantages and disadvantages, then this paper introduces redundancy structure in common useat present: ring network structure, hybrid redundant structure and double network cardredundancy structure, and puts forward the form could be adopted from the angle ofnetwork reliability.Finally, build the node models using the OPNET simulation software. According to theactual situation of substation, set the simulation conditions, summarize theinfluencing parameters of real time performance of process network andsubstation network, and the network structure which can be used by digital substation. Thework in this paper is a reference for the Substation Automation System and theconstruction of digital substation.