Technology Development & Applications
of Power Electronics-Based Controller
on Transmission Grids
Aty Edris
EPRI
Edris
Vision/Mission
• Power electronics is one of the fastest changing
“enabling infrastructure technologies” in electrical
engineering.
• It has made and continues to make significant
impacts on power and energy infrastructures, which
constitute one of the pillars of the foundation of our
society and the rest of the world.
• Power electronics-based controllers are the key
elements for transforming the electric grid from being
a “passive” to be an “active” system, i.e., flexible,
controllable, securely utilizable up to its maximum
capacity, and delivering power with the quality
needed for a “digital” society.
Edris
Transmission Grid “Complex Machine ??”
August 14 Blackout:
50+ M people
62 000 MW
Edris
Transmission Grid Issues
Uncontrolled Power Flows
Results are:
Low power transfer capability
Bottlenecks
Loop flows
Uncontrolled Flows
Power and Voltage Stabilities
Results are:
Generator Outages
Line tripping
Blackouts
Ontario
Hydro
New York
Power Pool
Loop flow
Edris
Available Transmission Grid Capacity??
Thermal Limit
UncontrolledPower FlowLimit
Stability Limit (SIL)
Voltage
(kV)
230
345
500
765
1100
SIL
(MW)
150
400
900
2200
5200
Typical Thermal
Rating (MW)
400
1200
2600
5400
24000
• Thermal Limits
• Uncontrolled Power Flows
• Stability Limits << Thermal Limits
Edris
The “Power” of Power ElectronicsBased Controllers
Dynamic Power
• Fast voltage support
Capacitive Mvar
• Controlled compensation response
• Counteracts power oscillations
• Ride-through during faults
• Smooth return to normal
Inductive Mvar
Valve Current
Steady State Power
• Voltage regulation
• Power flow control
Shock Absorber
• Power management
• Relief or elimination of bottlenecks
Edris
SYSTEM BENEFITS
Reliability & Quality of Power Delivery
Increase of Power Transfer
Full Control of Power Transfer
A E P U P F C C O N T R O L L IN G P O W E R O N
B IG S A N D Y - IN E Z L IN E
1 .05
IN E Z B U S V O L T A G E ( P U )
Without UPFC
1
0 .95
Big
Sandy
0
725
670
94% at -2 7°
100 % at -3 °
146
185
Wi th UP FC
Big
Sa ndy
10
20
30
40
50
60
70
80
90
1 00
Inez
2 00
L IN E R E A L P O W ER ( P ) M W
1 00
L IN E R E A C T IVE P O W E R ( Q ) M v a r
Q
0
8 50
777
- 2 00
100 % at - 1.2°
U PFC
60
P
- 1 00
Inez
99 % at -24°
- 3 00
0
374
UP FC
10
20
30
40
50
60
70
80
90
1 00
1 00
S H U N T IN V ER T E R R EA C T IV E P O W E R ( M v a r )
50
0
- 50
- 1 00
0
10
20
30
40
50
60
70
80
90
10 0
T im e ( s )
Edris
SYSTEM BENEFITS
Reliability & Quality of Power Delivery
Bi directional Power Flow &
Voltage Support
Fast and Transient Free
V and Q Control
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Use of Power Electronics in Controlling
Transmission Grid - Historical Perspectives
P
V
G
Thyristors
Switches
IC
IL
Static Var Compensator (SVC)
In the late
1970s
Thyristor-Controlled Series Capacitor (TCSC)
Thyristor switched and/or controlled Capacitors/Reactors
P
V
Gate
Turn-Off
Switches
IC
IL
Static Synchronous
Compensator (STATCOM)
G
In the
mid 1980s
Static Synchronous Series
Compensator (SSSC)
Voltage-Sourced Converter-based Controllers
Edris
Thyristor- versus Converter-based Controller
Thyristor switched and/or
controlled capacitors/reactors
•Limited performance
•Limited functionality
•Large footprint
Converter-based Controllers
•Superior performance
•Versatile functionality
•Smaller footprint
Edris
Thyristor- versus Converter-based
Controller
Higher Cost (25%)
Better Performance
Versatile Functionality
ConverterBased
Lower Cost
Limited Performance
Single Functionality
ThyristorBased
$ $$ $
$ $ $ $ $
Cost Breakdown
Edris
EPRI Development Objectives
Reduction of Overall Costs (goal 25%-30%)
Improvement of Reliability/Availability (goal 99%)
Featuring Structural Modularity and Scalability
Edris
Conceptual Design Study
Objective :
Innovative Converter-Based Concept
Meeting the targeted Objectives
Characterizing Criteria :
•
Sinusoidal output
•
Standard coupling transformer, if needed
•
Modular- using basic building block converters to
provide partial availability, and expandability both in
rating and functional flexibility
•
Reasonable operating losses
Edris
New Converter Platform
“Carrier-Neutralized Converter Platform (CNCP)”
VC
I
I
+
-
V dc
S ta tic S y n c h ro n o u s
S e rie s C o m p e n s a to r
- SSSC -
H-BRIDGE NO. 1 OUTPUT VOLTAGE
H-BRIDGE NO. 2 OUTPUT VOLTAGE
H-BRIDGE NO. 3 OUTPUT VOLTAGE
Building
Building
Building
Building
Block 1
Block 2
Block 3
Block 4
H-BRIDGE NO. 4 OUTPUT VOLTAGE
TOTAL OUTPUT
VOLTAGE
Edris
CNCP Meeting Targeted Objectives
• Cost Reduction Goal: 20%-25% cost reduction
- Provides potential for the lowest $/KVA- minimum number of
components and highest output power per total VA of used
semiconductors- Transformer-less Series Controller
• Reliability/Availability Goal: 99%
- No auxiliary components are needed for harmonic cancellation
- Transformer-less Series Controller
- Identical Building Blocks Module Structure for partial availability
- Wide-frequency band control operation-fast and effective
protection action during abnormal operation conditions and
contingencies
Edris
Power Electronics-Based Transmission Controllers
EPRI Sponsored (5 installations)
Commercial (8 installations)
Unified Power Flow Controller (UPFC):
“All Transmission Parameters Controller”
± 160 MVA Shunt and ± 160 MVA Series at
Inez Substation (AEP) 1998
Convertible Static
Compensator (CSC):
“Flexible Multifunctional
Compensator”
± 200 MVA at Marcy
Substation (NYPA)
2000 & 2003
Thyristor Controlled
Series Capacitor
(TCSC), 208 Mvar
Slatt Substation
(BPA) 1993
TCSC
UPFC
CSC
BTB
FACTS Controller
“Back-To-Back HVDC Tie”
36 MW at Eagle Pass (CSW)
2000
Static Synchronous
Compensator (STATCOM) :
“Voltage Controller”
± 100 Mvar STATCOM at
Sullivan Substation (TVA)
1995
STATCOM
Edris
World Wide INSTALLATIONS
„
„



‡
z
»
 

”
z
”


„
„
»
„ TCSC, Thyristor Controlled Series Capacitor
 STATCOM, Static Compensator
z
UPFC, Unified Power Flow Controller
» HVDC, High Voltage DC Voltage Source Converter
‡ CSC, Convertible Static Compensator
” BTB, Back to Back Voltage Sourced Converter
QUESTIONS?
Edris