IEEE Power & Energy Magazine - March/April 2018 - 31

(PU)

Building on this foundation, enhancing resiliency presents ure, the green arrows show the real power flow, and the contour
the challenge of modeling and simulating systems in very shows the per-unit substation voltages.
enhancing power grid resiliency requires being able to
unusual and often highly stressed situations. there is also the
need for more multidimensional modeling. severe events are accurately simulate the impact of a wide variety of events on
likely to affect not just the electric grid but also other infra- the power grid-and, potentially, on its coupled infrastrucstructures as well. at times, there is a need to model some of tures. the events most likely to stress power system resilthe underlying dynamics of the disturbance itself, such as in iency share two characteristics.
First, they have a significant impact. From a modeling perthe case of severe storms and gmds. this leads to the need
to develop cosimulation platforms that can model interactions spective, this means that they strain the power grid in new
between the power system and other critical infrastructure, and often unexplored areas. a consequence is that they will
also mostly likely stress the power system modeling software.
including control systems.
Key to the research and development needed for the cre- the degree of power system impact often requires detailed
ation of simulation tools for improved resiliency is access to modeling of physical systems associated with the initiating
large-scale, realistic models of electric grids. While some event. For example, correctly modeling the impacts of large
of this information has been available in the past, because earthquakes requires coupled modeling between the power
of the U.s. Patriot act of 2001, data relating to the U.s. elec- grid and seismic simulations.
second, because the events are low frequency, there may
tric power grid are now considered critical energy/electricity
infrastructure information (ceii), with access much more be little historical information to accurately quantify the
restricted. While most researchers can obtain some infor- risk. From a model perspective, some of the more extreme
mation, e.g., with nondisclosure agreements, these restric- events could be considered extreme manifestations of more
tions can sometimes hinder the free exchange of models common occurrences. thus, a large-scale physical attack
could be considered a more severe manifestation of more
and results.
a solution is to develop entirely fictional (synthetic) models regular disturbances, such as those due to weather. Others,
that match the complexity of the actual grid models but con- however, such as the grid impacts due to an electromagnetic
tain no ceii. this is now starting to occur, due in large part pulse caused by a high-altitude nuclear explosion, would be
to the dOe's advanced research Projects agency-energy (or entirely novel.
"arPa-e") grid data program.
the challenge for this research is
to determine the wide multitude of germane characteristics
of actual grid models and then
mimic these in entirely synthetic
models that can be freely shared.
a quite useful characteristic of
such synthetic models would be
for them to include realistic geographic coordinates so as to allow
coupling between the power grid
and either other infrastructures or
the actual geography.
One approach is to use an electric load distribution that matches
the actual population in a geographic footprint, then employ public
data on the actual generator locations, and finally use algorithms to
Per Unit Voltages
create an entirely synthetic trans1.08
mission grid. as an example, Figure 5 shows a 10,000-bus model
1.03
entirely synthetically sited geo0.98
graphically in the western United
states; the system has a total of
seven different nominal transmisfigure 5. Synthetic models, such as this 10,000-bus model located in the western
sion voltages (765, 500, 345, 230,
United States, allow for the study of power grid resiliency without the disclosure of
161, 138, and 115 kV). in the figconfidential information about the actual grid.
march/april 2018

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Table of Contents for the Digital Edition of IEEE Power & Energy Magazine - March/April 2018