IEEE Electrification - September 2020 - 20

As projected, power
electronic inverters
that would be
installed along with
wind and solar
generation would
account for about
30% of the U.S.
electricity need
in 2050.

fractions of 12.5% wind energy and
17.5% solar energy in 2050 in the
U.S., which correspond to 205.7 and
449.8 GW of installed capacity, respectively. As projected, power electronic
inverters that would be installed
along with wind and solar generation
would account for about 30% of the
U.S. electricity need in 2050. To put
this into perspective, today's shares of
hydro- and coal-based electricity in
the U.S. are 7 and 24%, respectively.
Power electronics, such as highvoltage dc (HVdc) and FACTS, has
been used for electric transmission
systems in the past several decades.
Geographical imbalance between
generation and load and the need to
transfer wind and solar generation to
load centers have accelerated dc transmission development around the world. Many HVdc and ultra-HVdc
(UHVdc) transmission infrastructures are in service or
under construction in China because the energy resources
in western China are far away from the load centers in
eastern China. In December 2018, the Changji-Guquan
UHVdc project commissioned a 3,293-km, 1,100-kV
UHVdc line connecting the northwestern Xinjiang Region
to central Anhui Province at a transfer capacity of 12 GW
of power, enough to power 50 million Chinese households.
In Europe, the conversion of existing multicircuit highvoltage ac (HVac) transmission infrastructures to HVdc or
hybrid ac/dc overhead lines is becoming a predominant
measure taken to accelerate grid reinforcements. Studies
have demonstrated that future hybrid ac/dc lines in the

New Vehicle Sales of Battery-Powered Vehicles
(AEO2020 Reference Case)
Millions of Vehicles
2019
3
History Projections

Total Battery Electric

300-mi Electric Vehicle
Hybrid Electric
200-mi Electric Vehicle

0
2010

2020

2030

2040

Plug-In Hybrid Electric
100-mi Electric Vehicle
2050

Figure 3. The EIA projected two million EVs by 2050. (Source: EIA;
used with permission.)

I E E E E l e c t r i f i cati o n M agaz ine / SEPTEMBER 2020

Swiss transmission network will be
beneficial because their use can lead
to a reduction in ac line loading, lower
operating costs, and increased utilization of the network infrastructure by
enabling higher flows. Germany has
been installing a large number of
HVdc transmission systems to allow
new offshore wind generation from
German waters of the North Sea to
connect to the onshore ac network.
One of these HVdc links, the Dol-Win3
HVdc offshore transmission system,
has a 900-MW rating at ±320 kV and is
configured as a single symmetrical
monopole system.
In distribution systems, inverters
are also becoming ubiquitous because
the number of significant distributed
photovoltaic (PV) systems, EV charging stations, and modern electric loads is increasing. Of the 449.8-GW solar generation projected by EIA for 2050, 138.4 GW would be
derived from distributed PVs. EIA also projected an
increase in EV sales to about two million in the United
States in 2050 (Figure 3). Traditional electric loads are being
transformed as well. From large loads, such as industry
motors and building heating and cooling equipment, to
small devices, such as computers and solid-state lighting,
more and more of the controls are being implemented
with power electronic converters such as those for variable frequency drives and all kinds of switched-mode
power supplies and battery chargers.
Power electronics is trending to become ubiquitous
throughout the power system from generation to transmission to end uses. Such a high penetration of power
electronics is poised to make significant changes in power
system operation landscapes and dynamic characteristics.
In some parts of the world, power systems have already
experienced the impact; e.g., the 9 August 2019 U.K. power
outage and the 29 September 2017 South Australia blackout, where high penetration of power electronics interacted with system faults in unprecedented ways. We must
examine such impact and how power electronics could be
utilized to enhance power system operation and control,
as discussed in the following sections.

The Impact of Ubiquitous Power Electronics
on Power System Dynamics
The power system is a complex system with inherent
dynamics. Historically, the dynamics have been dominated by massive rotating machines in conventional largescale thermal and hydro generators. With the increasing
power-electronics-connected generation and load, the
power system dynamics will no longer be dominated by
the conventional generators, and operating such a power
system will require entirely new approaches.

IEEE Electrification - September 2020

Table of Contents for the Digital Edition of IEEE Electrification - September 2020