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UR FAMILY – COMMUNICATIONS GUIDE
OVERVIEW
CHAPTER 3: IEC 61850 COMMUNICATION
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The complete set of logical devices in an IED are combined into an entity at the next level up in the hierarchy known as a
Server. Only one server exists in most IEDs, including UR devices, so a server can usually be considered synonymous with
the IED. The logical devices in an IED can be arranged in a hierarchical structure. Certain entities like revision counters have
a scope that extends to lower levels that do not contain an instance of that entity. UR family devices arrange their logical
devices such that the Master logical device is the root of the hierarchy, and all other logical devices are direct descendants
of Master.
When a particular data attribute or data object needs to be referenced by an SCL configuration file, in many cases the
name of each level in the information hierarchy are independently specified. For instance, to specify the reception of the
power of AC source 1 from an external IED, SCL can contain the following:
<ExtRef iedName="Fdr1" ldInst="Meter" prefix="ACsrc" lnClass="MMXU" lnInst="1" doName="TotW"
daName="mag.f" fc="MX" />
In other cases, an ObjectReference is used to identify the data attribute. An ObjectReference concatenates the names of
each hierarchical level with defined delimiting characters. For instance, the ObjectReference for the previous example
looks like the following:
Fdr1Meter/ACsrcMMXU1.TotW.mag.f
This format is known as the ACSI ObjectReference format, which is used exclusively in SCL, and in communication
messages where the value of a data attribute containing an ObjectReference is being transmitted. However, in
communications messages where an ObjectReference is a reference to the entity whose value is being communicated, it is
reformatted according to the MMS addressing scheme specified in IEC 61850 8-1. Thus on the wire, one can see a
message requesting the present value of source 1 power identifying the requested data attribute as
Fdr1Meter/ACsrcMMXU1$MX$TotW$mag$f
3.1.3 Datasets
A dataset is an ordered list of member data objects and/or data attributes. Datasets
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Allow for a client to get the values of all members of a dataset with a single request rather than having to individually
request each member
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Are used to define which data attributes to include in a GOOSE message or a sampled value message or a report
A dataset member can be either a functional constrained data attribute (FCDA) or a functional constrained data object
(FCD). An FCD is a structure containing all the data attributes of a data object or composite data object as explained in the
previous section, except that only those data attributes with function constraint code matching the code configured for
that member are included. An FCDA is to all intents and purposes a single data attribute or constructed data attribute; the
words "functional constrained" are superfluous. Note that a Substation Configuration Language (SCL) element with tag
"FCDA" is used to specify both FCDAs and FCDs. If the FCDA element attribute daName is omitted, an FCD is specified. If the
FCDA element attribute daName is included, an FCDA is specified.
UR devices accept both FCD and FCDA as dataset members.
The standards allow dataset names to be configured in SCL files as required, as do UR devices. The standards define a
service that creates a dataset online through MMS services, but UR family devices do not implement that service. Datasets
in UR devices must be pre-configured.
The following figure shows an EnerVista UR Setup dataset configuration page. Members are selected from a drop-down
list or by dragging and dropping. Datasets also can be configured from a GOOSE or Report configuration page. Note that in
EnerVista UR Setup the format of references to dataset members is:
<ldInst>.<LNName>.<fc>.<doName>.<daName>
where
