IEEE Power & Energy Magazine - January/February 2016 - 52

EastCentral
SouthSoutheast

NorthNortheast

WestCentral
SouthSouthwest

NorthNorthwest

framework, dividing a bulk power
grid among nine participants. the
Northwest
North
Northeast
region of modeling responsibility
assigned to each participant is called
a "frame," and the framework is
West-Northwest
North-Central
East-Northeast
completed by 12 "boundary" parts,
one for each place where two participants have ties, and so must
agree about how their adjacent
West
Central
East
models fit together.
both frames and boundaries
in
a
framework define roles that
West-Southwest
South-Central
East-Southeast
are filled by eQ model parts.
consider for a moment what is
required for North and central to
Southwest
South
Southeast
marry their models properly. For
each tie, they have to sit down and
agree about some minimal comfigure 1. An interconnection model partitioned among nine participants.
mon bit of modeling that neither
party
will
change
without
consulting the other. in fact, what
in this vision, the two most recognizable characteristics
of a building block model part are its type (which defines the this does is to create three sets of data: the set that North can
kind of information it contains) and its source (which defines change by itself, the set that central can change by itself,
the portion of the grid that it represents). the grand idea is and the set that can only change by North and central acting
that model parts may be assembled in different ways to cre- together. in the ciM, each of these three sets is captured by
an eQ model part. roughly, it goes like this:
ate all the necessary analytical models.
✔ North and central together define North-central, an
eQ boundary model part containing the objects that
Creating a Framework of Model Parts
make up their agreement on mutual modeling.
the ciM encourages (but as per requirement eight does not
require) entities participating in a grid to get together and
✔ North and central then separately define model parts
formally define their areas of modeling responsibility so that
that fit into the North and central frames respectively,
each datum has a single source and each set of data from a
each of which may be individually validated as adhering
given source fits together with each other set. this is called
to the agreement simply by verifying that their dangling
a "model framework."
references all properly terminate in the North-central
the primary agreement on a framework is made at the level of
boundary model part.
type "eQ" (i.e., equipment) model parts, which defines what grid
in this scheme, the fact that validation only requires testing
equipment is represented in a model. Figure 1 shows a very basic against the immediate boundary model parts for the frame is
very important because it means
that a set of consistent model parts
can be established without ever
assembling the whole framework in
one place.
ciM exchanges do not require
that this sort of partitioning occur
in any particular way. the longrange expectation is that partitioning will ultimately take place in
layers, as illustrated in Figure 2,
in which the model parts of the top
blue layer are composed of a purple layer framework and the model
parts of the purple layer are composed of a further red layer framework, and so on. in most cases,
given the nature of electric grids,
the top layers will tend to be the
figure 2. The layered partitioning of a model framework.
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Table of Contents for the Digital Edition of IEEE Power & Energy Magazine - January/February 2016