  This chapter summarizes the results obtained from a test bed, which is
composed of a microgrid and a wireless network, both relying on real and
practical premises. This test bed aims to evaluate application protocols
considered in the transport layer of the standard IEC-61850. The application is
a data gathering system, where IEC-61850 messages are transmitted from and
between different elements in a microgrid system, such as IED, publishers, and
subscribers, which are node elements that are part of the utility grid. The
standard IEC-61850 defines many protocols, such as SV, GOOSE, and MMS, each of
them with a variety of requirements and sharing similar transport communication
protocols, such as TCP and UDP. Hence, a testing framework is used in the test
bed in order to evaluate the performance of these protocols aiming to enable
the communication in a real microgrid deployment. The IEC-61850 messages
transported by TCP or UDP are transmitted to a centralized location, where a
local database stores the information under different test scenarios and using
different transmission sample times. The overall results are promising and
indicate that the protocols based on TCP in combination with a 5G cellular
network architecture would be suitable for most applications within the studied
microgrid case. In the case of UDP, the performance indicated some specific
constraints related to the multiple access nature of simultaneous transmissions
and also based on the SINR.
