IEC 61850 Protocol overview

What is IEC 61850 ??

• IEC 61850 is a global standard for “Communication Networks and Systems in Substations”

• It specifies an expandable data model and services

• It does not block future development of functions

• It specifies no protection or control functions

• It supports free allocation of functions to devices

• It is open for different system philosophies

• It provides the Substation Configuration description Language (SCL)

• It supports comprehensive consistent system definition and engineering

• It uses Ethernet and TCP/IP for communication

• Provides the broad range of features of mainstream communication

• It is open for future new communication concepts

History

• International Electrotechnical Commission (IEC) is global

• Publishes international standards for all electrical, electronic and related technologies.

• The IEC members are the national standardization organizations  i.e. not individuals nor companies.

• Experts in the technical committees represent their country i.e. not themselves or their employer

• IEEE and EPRI work under a similar charter in North America

IEC 61850:“COMMUNICATION NETWORKS AND SYSTEMS IN SUBSTATIONS”

• IEC 61850 is the first really global standard in the Electric Utility field

• Supported also in the ANSI/IEEE world

• Some 60 experts from Europe and North America have jointly developed the IEC v61850

• Includes the UCA 2.0 as a subset

• All 14 parts of the IEC 61850 were published in 2004/2005

• Influences other electric areas

• Wind power plants, Hydro power, Distributed Energy Resources.

• Implementation in progress by all major vendors

Objectives for the IEC 61850

Reduce cost from cradle to grave and into next generation:

• Interoperability

• IEDs from different vendors can exchange and use information over a common communications media.

• The functionality in different devices is however not necessarily the same. Therefore no interchangeability of devices from different vendors!

• Engineering and configuration data is portable between vendor tools

• Open IED description

• Reduces the engineering and configuration

• IEDs capabilities are described in a standardized way

• Proprietary functions, solutions, and data are still available and Allowed

• Communication closer to Power Apparatus

• Communication, data acquisition, and control capabilities will be directly imbedded into the primary equipment

• Free configuration

• Free allocation of functions in centralized or decentralized system configurations.

• Reduction of conventional wiring

• LAN instead of multiple copper wires

• Future proof

• Utility and Vendor investments shall be long lived in spite of fast changing technology

• The standard is able to follow the progress in communication technology as well as evolving system requirements.

Logical Nodes

• Functions or equipment used in power systems are represented in Logical Nodes, LN

• All information and functions in a substation is structured in atomic units, the LNs

• Each LN provides a list of well organized and named information Complex functions use a set of LN required to represent the function

• Services enable the exchange of the information in LNs between IEDs

• Example: the LN for a Circuit Breaker has the generic name XCBR

• New logical nodes can, if required, be created according rules defined in the standard

The substation LAN

• IEC 61850 specifies only the interface to the substation LAN

• The LAN itself is left to the system integrator

• The Ethernet LAN is a subpart of the station and needs engineering, configuration, supervision, and control as any other subpart

• A network management system is appropriate

• The LAN topology depends on a number of constraints:

• Operational requirements for the substation

• Size of the substation

• Reliability and availability

• The substation LAN as a whole will likely be separated into a station bus and one or more process buses

• Experience from previous substation communication architectures have shown that this is a sensible approach

Engineering and Configuration

• Savings from efficient IED engineering

• IEDs are engineered using manufacturer specific IED configuration tools

• Configuration tools translate the IED capabilities and configuration to the SCL (Substation Configuration description Language)

• SCL enables information exchange between IED configuration tools from different manufacturers

• SCL secures backwards compatibility between different versions of IEDs and IED configuration tools

Migration to IEC 61850

• Migration is technically possible as

• Replacement of station level devices

• Total or partial replacement of bay level devices

• Total or partial replacement of process level devices

• Extension with one or more bays

• Migration may not be profitable

• Two kinds of maintenance types in mixed installations

• No functional benefits

• Consider to migrate the total substation!

• Station computers and gateways will for long be compatible with current station bus protocols/interfaces

• Separation of communication and operator functions will allow for mix of station bus protocols, e.g. IEC 61850-8-1 and LON

• Problems if the station bus is used for station wide fast functions, e.g. interlocking, transfer between two buses may take time

Migration on Bay and Process levels

• Replacement of single IED

• Replace with plug compatible IED, if possible an IEC 61850 compatible one

• Retrofit of bay

• Select an IEC 61850 compliant set of IEDs, vendors will have IEC 61850 compliant IEDs with interfaces compliant to today's

• Extension with new bay

• As for retrofit but consider also a full process bus

• Retrofit of primary equipment or transducer/actuator

• Same as retrofit or new bays

Conformance Tests

• The conformance tests include verification of the vendor provided information and tools, as for example

• The formal SCL description of the IED in the ICD file, IED Configuration Description file

• The SCD, System Configuration Description, file that describes the system used for the verification of the IED.

• Conformance tests can be performed by the vendor himself or by an independent test organization as KEMA

• Interoperability between products from different vendors guaranteed by

• Quality Assurance program during development, market introduction, and project execution

• Conformance tests as type test for the communication capabilities

IEC 61850 – Benefits and Conclusions

• The standard for substation automation!

• Higher degree of flexibility though interoperability between IEDs from different vendors

• Taking full advantage of future innovations within Substation Automation and communication technologies

• Promises cost reductions from design to operation and maintenance!

• Substation architecture adapted to your requirements

• Gives the opportunity to select ‘Best value for money’

• Embraced by vendors and users equally!