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Integration of Iot technologies into the Smart GridBog'liq sensors-22-02475-v2Sensors
2022
,
22
, x FOR PEER REVIEW
9 of 18
“BCU1M19/C1/LBAYMMXU1/A/phsB/cVal/mag/f”. These steps are represented inside
numbered circles, as shown in Figure 5; the numbers are assigned according to the tem-
poral sequence of the steps. In the first step, the Web User submits a POST request includ-
ing the identifier of the BDA whose data type he is interested in and the details about the
Broker to be used for the publication (this last piece of information is not shown in Figure
5 due to the lack of space). In order to accomplish the user’s request, the Middleware will
analyze the SCL data model description maintained by the Local SCL Repository (step 2),
looking for the SCL description of the BDA in the DataTypeTemplates section of the SCL
file associated with the Web User. Figure 5 shows the piece of the SCL DataTypeTemplates
section relevant to the requested BDA, inside the callout. The SCL description of this data
type is translated into JSON format, thus obtaining the payload shown in Figure 5 close
to the step number 3. This payload is published to the Broken chosen by the Web User.
The IEC 61850 Web Platform will send the topic identifier as a POST response to the Web
User (step 4). In step 5, the Web User will subscribe to this topic on the specified Broker.
Subscription will allow the Web User to receive an MQTT frame containing the requested
BDA data type in JSON format (step 6).
Figure 5.
Example of the publication of the description of a Basic Data Attribute Type.
According to the example shown in Figure 5, the Web User must be aware of the
identifier “BCU1M19/C1/LBAYMMXU1/A/phsB/cVal/mag/f” of the BDA featured by the
attribute name = “f”. This happens in two scenarios; the first is the simplest and occurs
when the Web User holds a list of pre-configured identifiers, for each of which he needs
to know the relevant data type. The second scenario is that the Web User has a complete
knowledge of the current structure of the hierarchical data model of the IEC 61850 server;
on the basis of this knowledge, he is able to specify whatever identifier he desires. Some-
times these two scenarios cannot be realized, and the Web User may have to explore at
run-time the current IEC 61850 data model maintained by a specific server, until he can
find a particular data type and the relevant identifier. For this reason, the implementation
of the proposed platform includes particular solutions to allow the Web User to acquire
information about the current IEC 61850 data model present in the IEC 61850 Server.
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