IEEE Electrification - March 2022 - 23

These rules include power-sharing, coordinated protection,
synchronization, voltage regulation, and black start-
things that are taken for granted today and are fundamental
to grid operation all over the world. The main objective
was to ensure interoperability so that the grid could serve a
large number of customers and could accommodate various
generators, ranging from hydro to thermal. This was to
be done in an era when technology was evolving rapidly,
driven by an unregulated industry that was trying to establish
itself well before standards could exist or be enforced.
This cooperation between engineers and the equipment
manufacturers allowed the industry to rapidly grow and
scale to serve the entire nation. Today, we are at a similar
crossroads. As we make a transition to a future grid with
high penetration of renewables and inverter-based
resources (IBRs), it is important that consensus is rapidly
forged between diverse interest groups on what the operating
rules for the future grid should be. New initiatives,
such as the Department of Energy/Solar Energy Technologies
Office-funded Universal Interoperability for GridForming
Inverters Consortium, are attempting to create
such a consensus (https://www.energy.gov/eere/solar/
solar-energy-technologies-office-fiscal-year-2021-systems
-integration-and-hardware).
Key " intrinsic " attributes that have helped to ensure a
stable and functioning grid include: inherent communications-free
power-sharing between generators using a
P/f droop; stable operation under large transients and
faults; rapid, autonomous operation of protection gear to
isolate faults, synchronous generators with inertia
constant, H, in the range of 2-6 s; and generators that look
like voltage sources and loads that look like current
sources, all connected by a low-impedance network.
These attributes allowed early power grids to operate
even when there was minimum communication or computers
to optimize system behavior. A nearly constant
frequency became a fundamental part of the grid operating
paradigm. Frequency domain analysis and phasors
allowed the steady-state analysis of large complex interconnected
systems. As supervisory control and data
acquisition systems were developed and computational
resources became available, improved control and system-level
optimization became a key focus. Because the
real-time operation and protection of the system were
governed by rules and intrinsic and autonomous device
behavior, most of the new research in power systems was
focused on slow (5-15 min) system-level optimization,
including optimal power flow, congestion management,
and security-constrained economic dispatch. This basic
approach has worked very well for 100 years and would
have continued to work well for many more if we had not
decided to change the basic operating paradigm.
Framing the New Grid Operating Paradigm
The new operating paradigm is driven by climate change
and by plunging prices of new distributed energy resources
(DER) technologies, where photovoltaic (PV) and wind,
including several hours of energy storage, are already below
the price of energy from coal or gas plants. In Europe, we are
already seeing frequent conditions where DERs represent
Figure 1. A joint meeting of the IEE and the AIEE, St. Louis, September 1904 (Source: Cohn 2017).
IEEE Electrification Magazine / MARCH 2022
23

https://www.energy.gov/eere/solar/solar-energy-technologies-office-fiscal-year-2021-systems-integration-and-hardware https://www.energy.gov/eere/solar/solar-energy-technologies-office-fiscal-year-2021-systems-integration-and-hardware https://www.energy.gov/eere/solar/solar-energy-technologies-office-fiscal-year-2021-systems-integration-and-hardware

IEEE Electrification - March 2022

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