IEEE Electrification - June 2021 - 53

that excite underfrequency/overfrequency events are
known to concurrently stimulate power oscillation
modes, thereby impacting system stability. This operating
mode is utilized for simultaneously providing fast frequency
response both during underfrequency/overfrequency
events, and dynamic reactive power control for example,
for power oscillation damping. This operating mode is
portrayed in an expanded manner in Figure 4. During
underfrequency/overfrequency events, the PV-STATCOM
control dynamically increases or decreases the active
power output of solar PV system and modulates it to
alleviate system frequency variations, as shown in
regions C1 and C2, res pectively. Concurrently, reactive
power is dynamically modulated with the inverter capacity
remaining after active power modulation.
PV-STATCOM Control for
Critical Motor Stabilization
A
Need for Stabilization of Motors
Induction motors (IMs) are extensively
employed in various industries
such as petrochemicals,
process control, rolling mills, mining,
automotive, and so on. Stalling
of these critical IMs, even for a few
minutes, can cause significant
financial loss to the industries as
the complete batch of products
being transported by these motors
can get damaged. In the petrochemical
industry in Ontario, the
economic loss estimated for just
1 h of motor cessation is about
US$1 million. These motors are
especially prone to shut down if
served by weak distribution lines
and also if adequate dynamic reactive
power support is not provided.
FACTS Controllers for Motor
Stabilization
SVC and STATCOM are widely
employed for providing dynamic
reactive power support to ensure
stable operation of such critical
motors during system faults. A
−36/+8 Mvar SVC is installed in
Fairbanks, Alaska, to provide support
to a pumping station in the
trans-Alaska pipeline. A 41-Mvar
SVC is installed at a mining facility
at Malmberget, Sweden. Six
4.5-Mvar STATCOMs are installed
to provide dynamic reactive power
support for motors in a gold mine
100
Active Power
Reactive Power
50
Night
Night
B
A
B
A
in Matachewan, Ontario. A 16.8-Mvar STATCOM is used to
obviate voltage instability of large motors in a petrochemical
plant in the Gulf Coast in Texas. A 5-Mvar STATCOM is
installed to provide dynamic support to critical motors at
Seattle Iron and Metal Corporation. Finally, a 15-Mvar
STATCOM is utilized to protect critical motors from stalling
in a refinery in the Southern California Edison system.
Field Demonstration of PV-STATCOM Control
for Critical Motor Stabilization
The nighttime and daytime " PV-STATCOM " technology
was demonstrated for the first time in Canada (and perhaps
in the world) on 13 December 2016 in the utility
network of Bluewater Power, Sarnia, Ontario, and is
described here.
12 a.m.
6 a.m.
12 p.m.
Time of Day
A: Full-STATCOM
B: Partial-STATCOM
Figure 3. The combined modulation of active and reactive power.
A
100
Active Power
Reactive Power
50
Night
Night
B
C1
C
C2
B
A
6 p.m.
12 a.m.
12 a.m.
6 a.m.
t1
A: Full-STATCOM
12 p.m.
Time of Day
B: Partial-STATCOM
C: Curtailed Mode (C1: Under-Frequency Support;
C2: Over-Frequency Support)
Figure 4. Simultaneous modulation of active power and reactive power with preexisting power
curtailment.
IEEE Electrification Magazine / JUNE 2021
53
t2
6 p.m.
12 a.m.
PV Inverter Capacity (%)
PV Inverter Capacity (%)

IEEE Electrification - June 2021

Table of Contents for the Digital Edition of IEEE Electrification - June 2021