SVC PLUS Frequency Stabilizer Frequency and voltage support for dynamic grid stability SVC PLUS Frequency Stabilizer FrequencySVC PLUS Frequency Stabilizer FrequencySVC PLUS Frequency Stabilizer FrequencySVC PLUS Frequency Stabilizer FrequencySVC PLUS Frequency Stabilizer FrequencySVC PLUS Frequency Stabilizer FrequencySVC PLUS Frequency Stabilizer FrequencySVC PLUS Frequency Stabilizer FrequencySVC PLUS Frequency Stabilizer FrequencySVC PLUS Frequency Stabilizer FrequencySVC PLUS Frequency Stabilizer FrequencySVC PLUS Frequency Stabilizer FrequencySVC PLUS Frequency Stabilizer FrequencySVC PLUS Frequency Stabilizer FrequencySVC PLUS Frequency Stabilizer FrequencySVC PLUS Frequency Stabilizer FrequencySVC PLUS Frequency Stabilizer FrequencySVC PLUS Frequency Stabilizer FrequencySVC PLUS Frequency Stabilizer FrequencySVC PLUS Frequency Stabilizer Frequency

1. SVC PLUS
Frequency Stabilizer
Frequency and voltage support for
dynamic grid stability

2. The challenge:
Ensuring grid stability
with fewer rotating masses
As the infeed of power from
renewable sources continues to
replace conventional synchro-
nous power generation, the grid
frequency is becoming more sen-
sitive due to the reduced amount
of rotating machines. Now grid
operators are faced with the
challenge of providing sufficient
system inertia in their synchro-
nous generators with high rotat-
ing masses to stabilize the grid.
Because renewables have little
to no inertia, and can’t be used
for frequency stabilization, other
solutions are needed.
The challenge
While grids are undergoing fundamental changes in terms of power
generation, renewable infeed and ever-growing demand, power quality
and dynamic grid stability are at risk due to less synchronous power
generation.
The grid frequency is balanced to 50 Hz or 60 Hz by parity of power
demand and generation. The frequency must be kept within specific
limits, even in the event of an imbalance: for example, from a distur-
bance. After a fault, the frequency can only be stabilized by an inertial
response from generator-turbine sets. The mechanical kinetic energy
defines the frequency drop after disturbance until the operating reserve
is activated after several seconds by the primary frequency reserve (PFR).
Fewer rotating machines result in shrinking instantaneous reserves,
which increases the risk of exceeding critical frequency levels. This may
lead to load rejection or a blackout. Grid operators are forced to keep
power plants in operation in order to preserve the instantaneous re-
serve or to optionally invest in additional primary reserve. Some source
of fast frequency response (FFR) is urgently needed to cover the gap
between inertial response and operating reserves.
SVC PLUS FS: A convincing solution
By using a bulk number of supercapacitors, the new SVC PLUS frequency
stabilizer (SVC PLUS FS) is a cost-efficient, compact solution that can
emulate system inertia by boosting high active power into the grid
when needed. It also offers voltage support by means of reactive power
compensation.
Power
PFR* SFR*
FFR*
Future Today
Inertial
response
Operating
reserve
minutes
Time
Increasing
gap
Increasing
df/dt
2 seconds 10–30 seconds
* FFR =Fast frequency response
PFR =Primary frequency reserve
SFR =Secondary frequency reserve
The frequency control process: Future scenario
with increasing power imbalances and growing rate
of change of frequency due to less inertia
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3. Operational benefits
Blackout prevention
Dynamic voltage and frequency support com-
bined in one unit for optimal power quality.
Cost-effective solution
Low lifetime expenditures through compact,
space-saving installation with high power
density, low losses, and easy maintenance.
Short response time
Fast response time with high active power
output over several seconds.
High flexibility
The highly adaptable solution is suitable
for various applications through the flexible
adjustment of control parameters.
Independent of power generation
Not defined as a power generating unit and
therefore available to all transmission system
operators who aren’t allowed to operate
power-generating assets.
Environmentally friendly
Small footprint, no local CO2 emissions;
allows more grid access for renewable power
generators.
Proven technologies
High-end field-proven SVC PLUS technology
and innovative application of supercapacitors
combined into a reliable solution.
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4. Fast frequency stabilization and voltage support
Combining the SVC PLUS (modular multilevel STATCOM)
and supercapacitors that allow +/–50 MW of active power
output/input for up to several seconds, the SVC PLUS FS
is an ideal tool for providing a fast frequency response
within the first few seconds of a major grid disturbance.
While the STATCOM part provides inductive or capacitive
reactive power of +/–70 Mvar with a response time of less
than 50 ms, the electrical energy in the supercapacitors
is boosted into the grid to prevent load shedding or black-
out. The active power injection is activated by exceeding
the preset threshold values of either the rate of change of
frequency or specific absolute frequency values.
The active power response of the SVC PLUS FS substitutes
the kinetic inertia of large thermal power plants such as
coal-fired plants (see figure below). Depending on grid
conditions, the SVC PLUS FS can also absorb excessive
active power, preventing grid overfrequency.
Supercapacitors make the difference
The supercapacitors are the economical solution of choice
for providing high power density with a space-saving
footprint. Supercapacitors can be discharged similar to
standard capacitors, which simplifies their maintenance.
The compact SVC PLUS FS can be located decentrally,
wherever the reactive power injection and voltage control
is most efficient; this depends on the network topology.
Technical data
Key technical parameters of SVC PLUS FS:
• Can address any voltage level
• Footprint: 2,700 m2
• Active power: Pmax =+/–50 MW
• Reactive power: Q =+/–70 Mvar
• Available energy: 450 MJ
(upscaling to 4x units in parallel possible)
The SVC PLUS FS saves the grid operator from expensive
investments in must-run units or the need to provide addi-
tional primary reserves, as the figures below demonstrate.
Without providing additional primary reserve, frequency
will exceed the threshold value for load shedding in the
near future, probably by 2024.
The activation of bulk power infeed by SVC PLUS FS reduces
the rate of change of frequency and so covers the critical
time range until the primary reserve is activated. The
SVC PLUS FS eliminates the need for additional investments
in primary reserve.
Innovative solutions offer
more options for grid operators
Better support of power grids
2 3 4 5 6 7 8 9 10 11 12 Time (s)
Nuclear (1,250 MVA)
Coal (550 MVA)
Gas unit (200 MVA)
Base case (no additional power)
SVC PLUS
frequency stabilizer
(50 MVA)
Frequency (Hz)
50.0
49.9
49.8
49.7
49.6
49.5
49.4
49.3
49.2
49.1
49.0
48.9
Frequency (Hz)
50
49
Power (MW)
Primary injection 2014
Required primary
injection 2024
Event 2024 with
Load shedding primary reserve 2014
Time (s)
Time (s)
In the first five seconds, the power output of a 50-MVA SVC PLUS FS substitutes
the inertial response of, for example, a 550-MVA coal-fired power plant
Functionality of SVC PLUS FS
Event 2014
with primary
reserve 2014
4

5. 3
1 Supercapacitors 5 Phase reactor yard
2 SVC PLUS converter 6 MV switchyard
3 Control room 7 Power HV/MV transformer
4 Cooling 8 Connection to the HV switchyard
2
4
5
7
8
6
1
Frequency (Hz)
50
49
Power (MW)
Event 2024 with
primary reserve
2014 and FS
FS Primary injection 2014
Event 2024 with
Load shedding primary reserve 2014
Time (s)
Time (s)
SVC PLUS FS Supercapacitor Tower
(Maxwell Technologies
Supercapacitor Subsystem)
Grid
Transformer
Converter
Supercapacitors
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6. Practical applications
Versatility for sustainable success
Fast frequency response saves investments in primary rese
With a fast active power injection, the SVC PLUS FS covers the t
between a grid disturbance and the activation of operating res
Stabilize weak grids
The SVC PLUS FS combines dynamic voltage (STATCOM operat
and frequency support in one unit.
Reduce must-run units
The SVC PLUS FS provides various system services that reduce t
rve
ime gap
erves.
ion)
he
ventional
need of must-run capacity, which is currently provided by con
power plants.
Support and strengthen interconnections
Disturbances at interconnections can lead to a cascading event in
weak grids. To counter this, the SVC PLUS FS solution can flexibly and
quickly change between injection and absorption of active power, thus
strengthening the link by reducing overfrequency and frequency drops.
Grid access and grid code compliance for renewables
The SVC PLUS FS supports renewable power generation by providing
grid code compliance.
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7. Turnkey solutions and services
for trouble-free operation
While every power grid and every large industrial consumer has specific challenges
in terms of power quality, active and reactive power compensation, and grid stability,
our customized SVC PLUS FS turnkey solutions answer these challenges from a single
source, including customized consulting.
From technical clarifications to on-site support and turnkey solutions, our service
portfolio helps you optimize your assets and their performance throughout their
entire service life – with comprehensive solutions from just one provider.
Consulting and
feasibility studies
Financing Project management Engineering
and design
Site facilities
and civil works
Procurement
Factory testing
Transport
On-site installation
and commissioning
After-sales services,
deconstruction,
and recycling
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