IEEE Power & Energy Magazine - September/October 2019 - 21

The grid architecture synthesis process begins with a general
model that separates the characteristics of the grid into two sets,
arbitrarily labeled qualities and properties.

✔ limit propagation of undesired change effects
✔ strengthen desirable grid characteristics
✔ simplify design and implementation decisions.

This definition inherently assumes that while we are not working in a green field or developing country, the methods we
employ would work just as well in those situations. There would
be no need to identify legacy grid constraints, but the issue of
specifying new structures would remain.

Principles and Methods
The creation of a grid architecture involves some processes
familiar to most architects and engineers and other methods
that may not be familiar. We use two sets of principles in
the creation of grid architectures: one set is general and outlines the bases for developing good architectures, while the
other is specific to the particular architectural problem being
solved and varies from architecture to architecture. Some of
the general principles are as follows:
✔ A good architecture is one that meets the needs of the
stakeholders (especially the users) to their satisfaction, does not violate established principles of system
architecture, and takes into account the stakeholders'
relevant characteristics.
✔ Architectural structures should have formal bases
where possible to minimize ad hoc configurations
with unknown properties.
✔ Good architectures have conceptual integrity (free
from unnecessary complexities or exceptions, traceable back to basic core principles and rigorous bases, similar problems are solved in similar ways, and
so forth).
✔ Conceptual integrity is best achieved by a small, cohesive team of like-minded architects.
✔ Architecture should be the product of a single architect or small team with an identified leader.
✔ Stakeholders should be involved in the process as
much as possible, giving frequent and honest feedback
on all aspects of the system architecture.
✔ Essential functionality drives complexity, not architectural "elegance."
✔ Architecture should produce enforceable key constraints.
✔ The architect must be cognizant of the global system
when optimizing subsystems.
✔ Each component should be responsible for only
a specific feature or functionality or aggregation of
cohesive functionality. Components should be couseptember/october 2019

pled only through explicit structure, avoiding hidden
coupling where possible.
✔ Architecture should not depend on a particular commercial product or tool.
✔ The system architect is not a generalist but, rather, a
specialist in managing complexity.
This last principle is a crucial point: while we generate a variety of documents, drawings, and so forth in the
process of creating grid architectures, our primary product
is stakeholder insight. In that connection, grid architecture recognizes a very wide set of potential stakeholders,
including consumers, asset owners and operators, public
policy makers and regulators, utility executives, engineers
and grid operators, grid product developers and vendors,
and researchers. Because this article is not just for architects
and engineers, we use tools and methods that are much more
widely accessible than the typical architects' tool kit/workbench products.
For specific architectures, we also develop and apply a set
of principles that we use to guide the architectural decision
process, and we explicitly relate architectural elements to
them. Regarding the high grid resilience reference architecture we have been developing as part of the DOE Grid Modernization Initiative, we created and documented a set of
principles derived from a definition of resilience for the grid
and used those selected and combined structural representations to create a revised model for the grid with improved
inherent resilience characteristics.
The grid architecture synthesis process begins with a
general model that separates the characteristics of the grid
into two sets, arbitrarily labeled qualities and properties, as
shown in Figure 1. Qualities are those characteristics seen by
the users of the system; we think of them as existing in the
problem domain, and the users' expectations for these qualities are input requirements for the architecture. We label the
characteristics seen or required by the designers, builders,
and operators of the system as properties and treat them as
solution domain elements that are also requirements. This
model has practical implications for stakeholder communication and architectural evaluation, as further discussed in
this this section. The conflation of these two sets of characteristics can, and often does, cause considerable confusion,
and one role of the grid architect is to help stakeholders sort
them out.
We use the general model for architecture synthesis
shown in Figure 2. As with all architectural and engineering
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IEEE Power & Energy Magazine - September/October 2019

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