IEC_61850_-_Communication_Networks_and_Systems_In_Substations.pdf

IEC 61850 Communication Networks and Systems In Substations:An Overview for Users Drew Baigent Mark Adamiak Ralph Mackiewicz GE Multilin GE Multilin SISCO Markham,Ontario King of Prussia,PA Sterling Heights,MI IEC 61850 Communication Networks and Systems in Substations:An Overview for Users Drew Baigent Mark Adamiak Ralph Mackiewicz GE Multilin GE Multilin SISCO Markham,Ontario King of Prussia,PA Sterling Heights,MI Abstract Over the last decade,the“digitization”of the electron enterprise has grown at exponential rates.Utility,industrial,commercial,and even residential consumers are transforming all aspects of their lives into the digital domain.Moving forward,it is expected that every piece of equipment,every receptacle,every switch,and even every light bulb will possess some type of setting,monitoring and/or control.In order to be able to manage the large number of devices and to enable the various devices to communicate with one another,a new communication model was needed.That model has been developed and standardized as IEC61850 Communication Networks and Systems in Substations1.This paper looks at the needs of next generation communication systems and provides an overview of the IEC61850 protocol and how it meets these needs.I.Communication System Needs Communication has always played a critical role in the real-time operation of the power system.In the beginning,the telephone was used to communicate line loadings back to the control center as well as to dispatch operators to perform switching operations at substations.Telephone-switching based remote control units were available as early as the 1930s and were able to provide status and control for a few points.As digital communications became a viable option in the 1960s,data acquisition systems(DAS)were installed to automatically collect measurement data from the substations.Since bandwidth was limited,DAS communication protocols were optimized to operate over low-bandwidth communication channels.The“cost”of this optimization was the time it took to configure,map,and document the location of the various data bits received by the protocol.As we move into the digital age,literally thousands of analog and digital data points are available in a single Intelligent Electronic Device(IED)and communication bandwidth is no longer a limiting factor.Substation to master communication data paths operating at 64,000 bits per second are becoming commonplace with an obvious migration path to much high rates.With this migration in technology,the“cost”component of a data acquisition system has now become the configuration and documentation component.Consequently,a key component of a communication system is the ability to describe themselves from both a data and services(communication functions that an IED performs)perspective.Other“key”requirements include:High-speed IED to IED communication 1 Networkable throughout the utility enterprise High-availability Guaranteed delivery times Standards based Multi-vendor interoperability Support for Voltage and Current samples data Support for File Transfer Auto-configurable/configuration support Support for security Given these requirements,work on a“next generation”communication architecture began with the development of the Utility Communication Architecture(UCA)in 1988.The result of this work was a profile of“recommended”protocols for the various layers of the International Standards Organization(ISO)Open System Interconnect(OSI)communication system model.This architecture resulted in the definition of a“profile”of protocols,data models,and abstract service definitions that became known as UCA.The concepts and fundamental work done in UCA became the foundation for the work done in the IEC TC57 Working Groups 10,11,and 12 which resulted in the International Standard IEC 61850 Communication Networks and Systems in Substations1.II.Scope and Outline of IEC 61850 The stated scope of IEC 61850 was communications within the substation.The document defines the various aspects of the substation communication network in 10 major sections as shown in Table 1 below.Part#Table 1 Title 1 Introduction and Overview 2 Glossary of terms 3 General Requirements 4 System and Project Management 5 Communication Requirements for Functions and Device Models 6 Configuration Description Language for Communication in Electrical Substations Related to IEDs 7 Basic Communication Structure for Substation and Feeder Equipment 7.1 -Principles and Models 7.2 -Abstract Communication Service Interface(ACSI)7.3 -Common Data Classes(CDC)7.4 -Compatible logical node classes and data classes 8 Specific Communication Service Mapping(SCSM)8.1 -Mappings to MMS(ISO/IEC 9506 Part 1 and Part 2)and to ISO/IEC 8802-3 9 Specific Communication Service Mapping(SCSM)9.1 -Sampled Values over Serial Unidirectional Multidrop Point-to-Point Link 9.2 -Sampled Values over ISO/IEC 8802-3 10 Conformance Testing 2 Parts 3,4,and 5 of the standard start by identifying the general and