F.8
SEL-751A Relay Instruction Manual Date Code 20100129
IEC 61850 Communications
IEC 61850 Operation
Within ACSELERATOR Architect, IEC 61850 datasets have two main
purposes:
➤ GOOSE: You can use predefined or edited datasets, or create
new datasets for outgoing GOOSE transmission.
➤ Reports: Twelve predefined datasets (DSet01 to DSet12)
correspond to the default six buffered and six unbuffered
reports. Note that you cannot change the number (12) or type of
reports (buffered or unbuffered) within
ACSELERATOR
Architect. However, you can alter the data attributes that a
dataset contains and so define what data an IEC 61850 client
receives with a report. The last dataset, DSet13, is a list of the
Breaker Status and Control Data Attributes that are in the
SEL-751A.
Supplemental
Software
Examine the data structure and value of the supported IEC 61850 LNs with an
MMS browser such as MMS Object Explorer and AX-S4 MMS from Sisco,
Inc.
The settings needed to browse an SEL-751A with an MMS browser are shown
below:
Time Stamps and
Quality
In addition to the various data values, the two attributes quality and t (time
stamp) are available at any time. The time stamp is determined when data or
quality change is detected.
The timestamp is applied to all data and quality attributes (Boolean, Bstrings,
Analogs, etc.) in the same fashion when a data or quality change is detected.
However, there is a difference in how the change is detected between the
different attribute types. For points that are assigned as SER points, i.e.,
programmed in the SER report, the change is detected as the receipt of an SER
record (which contains the SER timestamp) within the relay.
For all other Booleans or Bstrings, the change is detected via the scanner,
which compares the last state against the previous state to detect the change.
For analogs, the scanner looks at the amount of change relative to the
deadband configured for the point to indicate a change and apply the
timestamp. In all cases, these timestamps are used for the reporting model.
Functionally Constrained Data Attributes mapped to points assigned to the
SER report have 4 ms SER-accurate timestamps for data change events. In
order to ensure that you will get SER-quality timestamps for changes to
certain points, you must include those points in the SER report. All other
FCDAs are scanned for data changes on a 1/2-second interval and have 1/2-
second timestamp accuracy. See the SET R command for information on
programming the SER report.
The SEL-751A uses GOOSE quality attributes to indicate the quality of the
data in its transmitted GOOSE messages. Under normal conditions, all
attributes are zero, indicating good quality data. Figure F.3 shows the GOOSE
quality attributes available to devices that subscribe to GOOSE messages from
SEL-751A datasets that contain them. Internal status indicators provide the
information necessary for the device to set these attributes.
NOTE: Do not edit the dataset
names used in reports. Changing or
deleting any of those dataset names
will cause a failure in generating the
corresponding report.
OSI-PSEL (Presentation Selector) 00000001
OSI-SSEL (Session Selector) 0001
OSI-TSEL (Transport Selector) 0001
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