ABB COM600 Station Automation Series User Manual page 18

COM600 3.2
18
COM600 Station Automation Series
User's Guide
Figure 2.3.5-1 Overview of IEC 61850 model usage
The smallest unit in the IEC 61850 modelling is a data attribute which is linked to an
OPC item in the OPC server. A data attribute can be, for instance, the state value of a
double point object (stVal), quality information (q), or timestamp (t). In the OPC server
some of the services are also mapped to the same level as the attributes. This means that,
for example, control services (such as ctlOperOn, ctlOperOff) for operating a double
point object are available as OPC items.
For different types of data, the IEC 61850 standard defines over 30 common data classes
including a set of mandatory and optional attributes and services. For example, common
data classes are defined for Controllable double point (DPC), Single point status (SPS)
and Measured value (MV).
Furthermore, the standard defines approximately 90 functional groups of data, based on
common data classes. These groups are called logical nodes. Examples of logical nodes
are controllable switch (CSWI) and distance protection (PDIS).
Logical nodes can be further grouped below logical devices (LD), forming logical groups
within a physical device (IED), see Figure 2.3.5-2.
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