IEEE PES T&D Conference & Exposition 2022 - 98

table 1. Comparison of Various Voltage Regulation Technologies.
Voltage Regulation Technology
Tap-Changing Voltage Regulator
Static VAR Compensator
Switched Reactor/Capacitor Bank
Fixed Reactor/Capacitor Bank
Dynamic Voltage Restorer
Shunt Active Filter w/ Energy
Storage
D-STATCOM
Mitsubishi Electric Power Products,
Inc. Power Quality Compensator
PQ Support
N/A
Reactive Power Only
Reactive Power Only
Reactive Power Only
Reactive Power Only
Real/Reactive Power
Reactive Power Only
Real/Reactive Power
Control Type,
Response Time
Coarse Stepped, > 30s
Fine Continuous, > 10ms
Coarse Stepped, > 10ms
Fine Continuous,
Instantaneous
Fine Continuous, > 25ms
Fine Continuous, > 40ms
Fine Continuous, < 10ms
Fine Continuous, < 10ms
threshold of their low-voltage ride-through curve and disconnect
from the grid. With these sources disconnecting
from the grid, the voltage event may be prolonged. In this
case, a fast-acting voltage regulation device should be sized
to boost the grid voltage above the low-voltage ride-through
curves of the solar inverters to stay online. For critical
load applications, many use the guidance of the Informa5
Size
−
+
+
+
+
+
−
−
Area
of
Effectiveness
Grid Level
Grid Level
Grid Level
Grid Level
Load Specific
Grid Level/Load
Specific
Grid Level/Load
Specific
Grid Level/Load
Specific
tion Technology Industry Council, which was derived from
the previous Computer Business Equipment Manufacturers
Association curve, with the published voltage curve shown
in Figure 1.
This is even more restrictive than a typical ride-through
curve for solar inverters, requiring voltage to be raised
above 0.7pu within 20ms to keep equipment operating without
interruption. The speed of the
required response
restricts
the
type of voltage regulation devices
that can be used at a distribution
grid level. As a result, this
limits the equipment to power
electronics-based regulators such
as the static VAR compensator or
D-STATCOM, or at the consumer
level, an uninterruptible power
supply. Referencing the discussion
earlier
Voltage
Tolerance
Envelope
in this section,
Prohibited Region
the
speed of these devices is enough
to react, but the amount and type
of power
required to support a
1.4
1.2
1
0.8
0.7
0.4
0.01c
No Interruption in Function
No-Damage Region
0.003 0.02 0.1 0.5 110
Duration in Cycles(c) and Seconds(s)
figure 1. Information Technology Industry Council power acceptability curve.
98
ieee power & energy magazine
1.1
0.9
severe short-term sag depend on
the feeder and impedance characteristics
of the grid. A unique
solution for momentary sags is to
bridge the gap between pure reactive
power support and the real
power support of an uninterruptible
power supply by combining a
D-STATCOM with a right-sized
real power source, such as ultracapacitors.
In this case, a high
level of voltage support can be
provided with combined real and
reactive power for up to about 5
seconds. Similarly, for a temporary
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