Research And Practice Of Communication Networks In Digital Substations Based On IEC 61850

Since SA(Substation Automation)technology was used in China more than ten years ago, it has been making a great contribution towards the secure and economic operation of power system. However, there are still some problems existing in SAS(SA system), for example the secondary connection is complex, the automation function is independent or overlapping, integrated application and interoperability are lacking, and the use of information is inefficient, which are due to the lack of digitalization and informatization in SAS.With the development of electric power industry and the deepening of the market reform in China, power quality and the secure and economic operation of power system are demanded increasingly.As the information source and executive terminal; digital substation is demanded increasingly as well.The inventions of ECT/EVT and intelligent switchgear make it possible to construct digital substation. High speed, credible and open communication network is the key of digital substation, especially the standard of communication networks and systems in substations- IEC 61850 provides the comprehensive standards for digital substation.This paper concerns about IEC 61850, CNDS (Communication Networks in Digital Substation based on IEC 61850), and the new type of digital protection platform applicable for digital substation. The significant achievements are as follows:◇Analysis of IEC 61850·The internal relationship between IEC 61850 and digital substation is described.·The connotations of IEC 61850 are summarized, which make IEC 61850 not only a communication protocol, but also a modeling method for substation automation function.·The technology characteristics of IEC 61850 are summarized, such as function leveling, object-oriented modeling, decoupling of function and communication, substation configuration description language, data object self-description,etc.·IEC 61850 information model is analyzed as object-oriented"class". The commonness and difference between information model and class are presented.Taking merging unit for example, the attribute and services of the information model are analyzed detailedly.◇Research on application of IEC 61850·The general steps of practicing IEC 61850 in system and equipment are summarized.·The two most important communication services, Sampled Value Class (SVC) and General Substation Event (GSE) , are analyzed systematically.·The Specific Communication Service Mapping methods (SCSM)of core ACSI model, GOOSE, SMV, GSE management, GSSE service, time and time synchronization are analyzed detailedly.·Three types of building methods of IEC 61850 information model are presented and compared detailedly.