Outcomes, Insights, and Best Practices from IIC Testbeds: Microgrid Testbed
Simulations
because of their inherent speed and
synchronization ability combined with being
programmable (especially helpful in a
testbed). Whether using CompactRIO or a
custom-built controller, FPGAs are, at the
low level, the technology of choice for IGBT
control.
The team can run simulated generation
profiles on each of the three inverter
cabinets to simulate solar, wind and storage.
The team discussed using real solar, wind
and storage – a possible plan for the future
but the simulations make it easier to model
multiple scenarios. For example, wind is very
dynamic. Literally, one second could
generate large output from the wind turbine
or wind farm, then five seconds later there is
next to nothing because that was a wind
gust. These are the types of profiles that are
very difficult to control because they happen
so fast.
From a TSN standpoint, the Microgrid
Testbed can synchronize pulses between the
controllers on the order of 100-
nanoseconds. Both of those technologies
(programmable FPGAs and TSN) are very
well positioned to help solve the microgrid
problems, certainly relative to dynamic
control
and
device-to-device
communication. However, the effort is
focused on the reality that this is a new
standard, a new protocol.
Traditionally, the edge sensors send data
back to a cloud or to a central distribution
management or energy management
system. That round trip from sensor back to
control action can take longer than the wind
gust. So by pushing control down to the
edge, connecting it with surrounding sensors
and other protection and control devices,
the testbed team can coordinate much
faster, response times. Again, this would not
be a problem if wind/solar were a small
percentage of the grid because the inertia of
the grid would simply absorb it into
unperceivable perturbations.
Expanding Into Larger Field Deployment
There are additional concerns around
distance as the testbed moves into a larger
field deployment and the need arises to
ensure synchronous coordination across a
larger space. The problem gets more
complex with scale because, at some point
there is a need to physically run a cable to
different locations. The TSN protocol is
designed to work at those great distances.
So, the problem emerges not from a
technology standpoint, but more from an
infrastructure standpoint. As all the different
parts are networked around the city and
country, all the switches and nodes must be
TSN-compliant along the path. This rollout
may look like the transition from 100Mbit
Ethernet to 1Gb Ethernet.
Speed
Grids around the world operate at 50 Hz or
60 Hz (cycles per second). These are
standards – such as VHS/Betamax, HD-
DVD/BlueRay – except there was no clear
winner even though they exist in the same
global industry, albeit typically continents
apart.
In a microgrid, many times – such as the
remote village application or the foreign
operating base examples mentioned earlier
– all of the control equipment could be in a
single substation. A substation could be a
building. It could be a big building or it could
There are multiple switches (IGBTs), inside
this inverter and they must be articulated at
the right time to get the proper frequency
output. FPGAs are great for IGBT control
IIC Journal of Innovation
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