IEEE Power & Energy Magazine - July/August 2020 - 21

Approaches for Regional
Transmission Operators

EXTREME WEATHER, SUCH AS HURRICANES AND
other storms, is the primary cause of widespread power
failure in the United States. Power failures can have a
significant impact on our society. With the increased frequency and intensity of these extreme weather events and
future risks brought on by an evolving resource mix and the
increased potential for cyber- and physical attacks, beyond
reliability, the resilience of the power grid is becoming more
critical. The energy industry is working to improve resilience to make the grid stronger and smarter so it can better
withstand disruptive events and reduce the magnitude and
duration of any power failures that do occur.
Many weather-related resilience improvements are located
in the distribution systems. In this article, we
focus on the regional transmission operator (RTO) perspective and provide an
overview of approaches to improve bulk
power system resilience. Based on our
experiences at PJM Interconnection, we
discuss improvements and challenges to
creating a more resilient system, looking at aspects of operations, infrastructure planning, markets, and cyber- and
physical security.

System and Market
Overview
PJM is responsible for ensuring
reliable power system operation
and efficient electricity market
operation in all or part of 13 states
and Washington, D.C.. It is also
responsible for the regional planning processes for generation and
transmission expansion to ensure
future system reliability. The
resilience of this region's bulk
power system, which is part of the
Eastern Interconnection of North
A mer ica, has broad s o c i e t a l

impact, producing approximately 21% of the U.S. gross
domestic product.
This system has more than 84,000 mi (135,000 km) of
transmission lines and 1,440-plus generation resources, with
a peak load greater than 165,000 MW. The system's reliability is bolstered by the largest competitive wholesale electricity market in the world, with more than 1,040 member
companies and US$50 billion in billing in 2018. The market
products include energy, capacity, ancillary services (such as
reserves and regulation), and financial transmission rights.
The total installed capacity of the system is greater than
186,000 MW, of which natural gas resources account for
roughly 40% (over 74,000 MW). Natural gas is becoming the
dominant fuel for our generation fleet on the basis of installed
capacity. We estimate that in three to four years, natural gas
will make up approximately half of the committed capacity
(Figure 1). The resource mix also includes more than 10,000 MW
of demand response (DR) resources.

Enhancing Bulk Power System Resilience
At PJM, resilience means the ability of the system to withstand
and reduce the magnitude or duration of disruptive events,
which includes the capability to anticipate, absorb, adapt to, or
rapidly recover from those incidents. Such high-impact, lowfrequency threats include extreme weather, electromagnetic
and geomagnetic disturbances, cyber- and physical attacks,
fuel security, and the loss of interdependent infrastructure
needed to maintain grid reliability (e.g., telecommunications).
All grid operators already comply with established North
American Electric Reliability Corporation (NERC), regional,
and transmission owner reliability standards. Resilience moves
beyond reliability, addressing the challenges and emerging risks
that existing reliability standards do not fully capture, including
✔ maintaining reliability in the face of disastrous events
✔ evaluating threats and protecting essential systems
based on assessed risks
✔ improving grid flexibility and control to adapt efficiently and quickly to postevent conditions
✔ slowing disruptive events and mitigating their impacts
as well as quickly recovering essential functions.

By Hong Chen, Frederick S. (Stu) Bresler III,
Michael E. Bryson, Kenneth Seiler,
and Jonathon Monken
july/august 2020

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IEEE Power & Energy Magazine - July/August 2020

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