IEEE Power & Energy Magazine - September/October 2019 - 42

These challenges drive two fundamental distribution grid
needs: 1) fully understanding the grid status in near-real time
(situational awareness) and 2) the ability to act upon operational issues that arise (distribution automation and control).
Therefore, systems and technologies are needed to monitor
and control the distribution grid, including telecommunications infrastructure to communicate with the distribution
technologies and back-office platforms such as distribution
management, demand response (DR), and DER management systems.
Grid modernization presents opportunities to solve these
technical challenges and transform the existing grid over the
next 20 or more years.
✔ Current: Significant growth of customer DERs has
outpaced the ability to properly address technical
and operational issues at all levels of the grid: bulk
generation, transmission, and the distribution system.
The rapid change in the operating characteristics of
the power system is challenging the operational capability of the system to provide essential services
and maintain the reliability of the electric supply
in Hawai'i.
✔ Near term: Continued customer DER adoption and
use of DERs as grid resources necessitate the integration of advanced grid technologies into the distribution system to enable cost-effective DER integration
and utilization. The grid will evolve into a conduit for
coordinated import and export of energy and related
services. This use of the distribution system represents a new paradigm for grid operations and further
emphasizes the importance of reliability and operational flexibility.
✔ Long term: There is a need to extend the integrated
grid platform to leverage energy storage, advanced
grid technologies, and cyberphysical infrastructure
upgrades that can incrementally evolve over time.
Such a grid can achieve the goal of 100% renewables
by 2045 with grid-scale and distributed resources
(both at approximately 3,000 MW) that are both intermittent and highly variable. Moreover, such a grid
would enable the convergence of multiple systems that
would create strong economic benefits for communities businesses, and customers as well as the infrastructure owners.

Hawai'i Grid Architecture
A modern grid should be based on a grid architecture that
addresses the challenges and opportunities presented and
one that also enables the right pieces to be added at the
right time and at the right level of investment to thoughtfully align customer and policy needs in a cost-effective
manner. As the Hawai'i Public Utilities Commission noted:
The complexity of the power grid has passed the point
where intuitive or siloed approaches to changes are
workable. ... The power of grid architecture would
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appear to be in its ability to aid in managing complexity, the use of which could well be the difference
between being able to actively shape the evolution of
the grid based on sound representation of a multiplicity of structures and the interactions involved, versus
passively allowing the grid to evolve in a bottom-up
manner and waiting to see what emerges.
Grid operational systems are evolving in complexity and
scale with the integration and utilization of DERs. This evolution increases the need for enhanced functionality related
to planning, operations, and support for operational markets.
However, this also introduces operational risks in the forms
of system complexity and vulnerability to cyberattacks. This
increased complexity goes well beyond what traditional distribution system designs can manage properly. To manage
the complexity, a scalable, extensible architectural approach
is needed that can address the multiple layers of resources
connected at transmission and distribution and behind the
meter on the customer's premises. Grid architecture is an
essential step in the development of a grid modernization strategy.
Three key architectural aspects were addressed in the
Hawaiian Electric Companies' grid modernization strategy:
1) layered architecture, 2) platforms, and 3) extensibility to
enable proportional deployment.

Layered Control Architecture
A layered architectural approach to operating the grid involves coordinating resources across three layers: customers,
distribution, and transmission. This layered approach allows
coordinated management of the complexity, security, and
control interfaces with DER aggregators and the flexibility to
interface with existing customer systems as well as with new
ones that will be added over time. Without proper coordination, managing this level of complexity will be problematic,
as many of these systems have nonstandard interfaces and
uncertain cybersecurity protocols.
Traditional distribution engineering architecture and
designs are inadequate to address these issues. Informationcentric architectures, focusing on information flows, are useful but not sufficient to address the physical aspects of the
modern grid. These are equivalent to having the plumbing
design for a house, whereas grid architecture is the whole
house blueprint. Given these issues, the Hawaiian Electric
Companies are pursuing a holistic grid architecture. One key
aspect of the layered approach involves control strategy. The
Hawaiian Electric Companies are pursuing a two-part control strategy: an approach for normal operating conditions to
utilize DERs as illustrated in Figure 2 and backup controls
to manage the output of DERs to maintain system reliability under abnormal operating conditions, a need unique to
Hawai'i's island grids.
The level of operational control and interfaces involves
several different types of DERs and controls within a distributed, layered architecture.
september/october 2019

IEEE Power & Energy Magazine - September/October 2019

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