DIN EN 61850-7-1:2012-04
EN 61850-7-1:2011
Implementations to reach interoperability have to be based on common understanding of definitions.
Therefore, the parts describing the data model contain mandatory semantic tables which have to be
considered very carefully.
The IEC 61850 series defines the information and information exchange in a way that it is independent of a
concrete implementation (i.e., it uses abstract models). The standard also uses the concept of virtualisation.
Virtualisation provides a view of those aspects of a real device that are of interest for the information
exchange with other devices. Only those details that are required to provide interoperability of devices are
defined in the IEC 61850 series.
As described in IEC 61850-5, the approach of the standard is to decompose the application functions into the
smallest entities, which are used to exchange information. The granularity is given by a reasonable
distributed allocation of these entities to dedicated devices (IED). These entities are called logical nodes (for
example, a virtual representation of a circuit breaker class, with the standardised class name XCBR). The
logical nodes are modelled and defined from the conceptual application point of view in IEC 61850-5. Several
logical nodes build a logical device (for example, a representation of a Bay unit). A logical device is always
implemented in one IED; therefore logical devices do not contain logical nodes from different IEDs.
Real devices on the right-hand side of Figure 3 are modelled as a virtual model in the middle of the figure.
The logical nodes defined in the logical device (for example, bay) correspond to well-known functions in the
real devices. In this example, the logical node XCBR represents a specific circuit breaker of the bay to the
right.
NOTE 2 The logical nodes of this example may be implemented in one or several IEDs as appropriate. If the logical nodes are
implemented in different IEDs, they need exchange information over a network. Information exchange inside a logical node is outside the
scope of the IEC 61850 series.
Based on their functionality, a logical node contains a list of data (for example, position) with dedicated data
attributes. The data have a structure and a well-defined semantic (meaning in the context of systems for
power utility automation or, e.g. more specifically, of substation automation systems). The information
represented by the data and their attributes are exchanged by the services according to the well-defined rules
and the requested performance as described in IEC 61850-5. The services are implemented by a specific
and concrete communication means (SCSM, for example, using MMS, TCP/IP, and Ethernet among others).
The logical nodes and the data contained in the logical device are crucial for the description and information
exchange for substation automation systems to reach interoperability.
The logical devices, the logical nodes and the data they contain need to be configured. The main reason for
the configuration is to select the appropriate logical nodes and data from the standard and to assign the
instance-specific values, for example, concrete references between instances of the logical nodes (their data)
and the exchange mechanisms, and initial values for process data.
5.4 Applications modelled by logical nodes defined in IEC 61850-7-4
Table 1 lists all groups of logical nodes defined in IEC 61850-7-4. Over one hundred logical nodes covering
the most common applications of substation and feeder equipment are defined. While the definition of
information models for protection and protection related applications is important because of the high impact
of protection for safe and reliable operation of the power system, the covered applications include many other
functions like monitoring, measurement, control and power quality.
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B55EB1B3E14C22109E918E8EA43EDB30F09DCCB7EF86D9
NormCD - Stand 2012-08