National Conference
of State Legislatures
April 2011
The Forum for America’s Ideas
Q U A N TA
SERVI CES
Quanta Technology
Advancing the Grid
BGE
Technology Provides New
Transmission
Options
January 4,
2008
Dr. Aty Edris
November 2007
Sr. Director and Executive Advisor
aedris@quanta-technology.com
National
Association of
Regulatory Utility
Commissioners
Global Reach - National Presence!
Quanta Technology HQ
Quanta Technology Offices
Quanta Presence
Quanta Technology Projects
Page 2
US Grid
Electro-Mechanical Systems
Page 3
Challenges
• Increased Transmission Capacity
• Maintain Power Delivery Stability
• Managed Real and Reactive Power Flow
Improved Reliability, Integrity, and
Efficiency of Transmission Grid
Smarten the Grid
4
Power Systems Complexity
Electro-Mechanical Systems
Complexity results in major
blackouts from time to
time, affecting millions of
people and loss of large
generating power
August 2003
February 2008
Page 5
Electric Power Grid Complexity
Ind.
Cap
Database:
Raw and pre-processed measurements
System configuration data
Increased
Transmission
Capacity
Information Exchange
Data Integration
DFRs
DPRs
PQ
Meters
RTUs
SERs
PLCs
CBMs
Operator Training
Power Flow
Stabilities
Reactive Power
Management
Data Exchange
Complexity Attributes
Power Flows are not Optimally Controlled
Reactive Power/ Reactive Reserve Need to be Managed
System Stabilities are not Fully Controlled
Inadequate Training for Planners and Operators
Lack of Effective Data Integration and Information Exchange
6
Limits of AC Transmission System
• Uncontrolled Power Flows
Results are:
– Low Power Transfer Capability
– Bottlenecks
– Loop Flows
1
3
U ncontrolled Flow s
4
2
O ntario
H ydro
N ew Y ork
P ow er P ool
5
Loop Flow
Therm al Lim it
100%
50%
0
1-2
1-3
2-3
2-4
2-5
3-4
Unused capacity
4-5
7
Reactive Power Puts a Limit on the
Full Utilization of Power Transmission
FOAM =“reactive power”
• Mvar Support is Exchangeable with MW
• The Exchange Rate could be up to 0.5 MW/Mvar
8
REACTIVE POWER SCALE
“Surge Impedance Loading (SIL)”
Ind.
“Light” Loading < SIL
Capacitive > Inductive
Cap.
• Overvoltage Risk
Loading = SIL
Cap.
Ind.
Inductive = Capacitive
Underutilized Transmission
“Heavy”Loading >SIL
Cap.
Inductive > Capacitive
Voltage Instability Risk
Ind.
9
STABILITY ISSUES
Transient Stability
Dynamic Stability
180
Transient instability
Negatively damped
Dynamic instability
Stable
120
60
Prefault
Rotor angle δ in degrees
Rotor angle δ in degrees
180
Poorly Damped
120
60
Reasonably damped
Prefault
tc = 0.1 s
tc = 0.07 s
0
0
1
2
3
4
0
5
0
Time t in seconds
1
2
3
4
5
Time t in seconds
Voltage Instability
Voltage
Tripping line L2
L1
System
Slight increase
in loading
L2
Collapse
Voltage
PL+jQL
t
0
10
20
30
s
10
Transmission Capacity Limits??
Unused capacity Voltage
Thermal Limit
U
Uncontrolled
ncontrolledPow
Power
er Flow
FlowLim
Limit
it
Stability
(SIL)
StabilityLimit
Limit (SIL)
(kV)
230
345
500
765
1100
SIL
(MW)
150
400
900
2200
5200
Typical Thermal
Rating (MW)
400
1200
2600
5400
24000
SIL is the Surge Impedance Loading
• Thermal Limits
• Uncontrolled Power Flows
• Stability Limits << Thermal Limits
11
Squeezing more MWs from the Grid
The objectives are:
• Increased Transmission Capacity
• Maintain Power Delivery Stability
• Managed Real and Reactive Power Flow
Improved Reliability, Integrity, and
Efficiency of Transmission Grid
12
New Transmission Technology Options
Dealing with Thermal Limit
• Dynamic Thermal Circuit Ratings Technology
• High Temperature Low sag Conductor
Power Flow Control and System Dynamics
• Power Electronics-Based Transmission
Controllers (FACTS and HVDC Technologies)
• Reactive Power Management
• Segmentation and Grid Shock Absorbers
Vision
• Wide Area Monitoring and ControlSynchrophasor Technology
13
New Transmission Technology Options
Thermal limit
• Dynamic Thermal Circuit Ratings Technology
• High Temperature Low sag Conductor
Power Flow Control and System Dynamics
• Power Electronics-Based Transmission
Controllers (FACTS and HVDC Technologies)
• Reactive Power Management
• Segmentation and Grid Shock Absorbers
Vision
• Wide Area Monitoring and ControlSynchrophasor Technology
14
Dynamic Thermal Ratings Technology
Results in 10%-15% Increase of transmission capacity
Monitoring
The
idea
Heat Balance Equation
dT
Qgen +Qsun = Qrad +Qconv + mC *
p dt
Video Sagometer
1500
1400
1300
1200
1100
1000
900
800
1
33
65
97
129
161
193
225
257
289
321
353
385
417
449
481
513
545
577
609
641
Conservative Criteria,
low wind speed, high ambient temperature
Rating - amperes
Static Thermal Rating
Dynamic Thermal Rating
Number
ofof15
minutes
Number
15 m
inute Periodsperiods
Weather Only (22 deg wind angle)
Tension/Weather
Static Rating
15
C3 – Conditionally Committed Capacity for Overhead Transmission
Lines- “Smart idea” for time-ahead generation scheduling
High Temperature Low Sag Conductors
Conventional, ACSR
Conductor
Heavy, Low Ampacity,
High Mechanical
Elongation
Clearance
New High Temperature
Low sag Conductors
Less weight, Higher
Ampacity, Higher
Strength Higher cost
17
New Transmission Conductors
Aluminum ConductorSteel Reinforced (ACSR)
3M Composite
Conductor
CRACComposite Reinforced
Aluminum Conductor
Sumitomo Gapped
Conductor
Conventional (reference)
Composite core (Alumina Fiber)
1.5-3.0 Ampacity improvement
Low thermal expansion
High strength-to-weight ratio
Costs 8-10 times
Composite core (thermoplastic)
1.3-2.0 Ampacity improvement
30% strength increase
25% weight reduction
Costs 1.5-2.0 times
Extra high-tensile galvanized steel core
Heat resistant aluminum alloy (added
zirconium)
Gapped heat resistant grease
30% less sag for the same temperature
1.5 -2.0 Ampacity improvement
Costs 2-3 times
18
New Transmission Technology Options
Thermal limit
• Dynamic Thermal Circuit Ratings Technology
• High Temperature Low sag Conductor
Power Flow Control and System Dynamics
• Power Electronics-Based Transmission
Controllers (FACTS and HVDC Technologies)
• Reactive Power Management
• Segmentation and Grid Shock Absorbers
Vision
• Wide Area Monitoring and ControlSynchrophasor Technology
19
Power Flow Control and Management of System Dynamics
Flexible AC Transmission
System (FACTS)
Technology
High Voltage Direct Current
(HVDC) Technology
Thomas Edison DC
Segmentation and Grid
Shock Absorber Concept
Power Electronics-based
Transmission Controllers
Reactive Power
Management Concept
Synchrophasor Technology
Nikola Tesla AC
Power Flow Control and System Dynamics
“HVDC and FACTS” have the ability to help in rerouting power to eliminate
transmission bottlenecks and prevent a potential of cascading outages
situation.”
Smart Transmission Grid
Increased transmission capacity
Improved flexibility and
controllability of transmission
grid
Bulk power transmission in the
Flexibility
GW range over distances of 1,000
kilometers and more
Reliability
Controllability
Accessibility
Reduction in CO2 emissions, grid
access of large wind, hydro, and
solar power plants
Increased robustness and
reliability of transmission grid
Power Flow Equation
V
1
δ
P
1
T r a n s m is s io n L in e
P
=
V
2
δ
2
X
V
1
V
1
2
X
s in (δ 1 -δ 2 )
Thyristor
Gate Turn-Off
Edris
22
Voltage-Sourced Converter
“A Building Block for New Transmission Controllers”
Vo
Transm
ission
lineline
Transm
ission
VL L
V0 V0
Transformer
Transformer
I I inducta
inductance
nce
Voltage
Sourced
sourced
Inverter
inverter
Gate Turn Off Switch
GTO, GCT, IGBT
Voltage sou rce
converter w ith
controlled
output voltage
If V L =V 0, I = 0
If V L <V 0, I = cap acitive
If V L >V 0, I = inductive
DC DC
cacapacitor
pacitor
Vo
V dV
c dc
Vo
Pulse-Width Modulation
Three-Level Switching
Edris
FACTS Technology
Electricity flows passively
P
V 1δ 1
T r a n s m is s io n L in e
Gate Turn Off
Power Switches
V 2δ2
X
P = V 1V 2
1
X
s in ( δ 1 - δ 2 )
Smart
Idea
Smart control of Electricity flows
Vpq
Transmission line
GTO
V1
Shunt Inez
transformer
I
P
Breaker
138kV bus
Series
V’1 Q
transformerTransmission
line
V21
Converter 1 (shunt)
to Big Sandy
Converter 2 (series)
V1
I sh
P
+ Vdc
AC
AC
V2
IGBT
Qconv1
Pconv1
Qconv2
Q
Pconv2
Gate signals
ETO
Converter 1
Converter 2V 1
Ish
Internal
converter
control
V’1(UPFC)
(shunt)
(series)
Unified Power Flow Controller
I
IqRef
Parameter
Settings
Vdc
System operation control
VpqRef
System variables:
P,Q,V 1 ,V’1 , etc.
Example of Field Application of Converter-Based Technology
The Convertible Static Compensator installed at NYPA’s Marcy substation
Relieving Major Transmission Bottleneck
Marcy
Bus
New
Scotland
B R12
line
T R-SE2
Coopers
Corners
BR11
line
T R-SE1
T R -SH
LV1
M O D-1
M
CS-1
LV2
MO D-2
C S-2
M
M OD-3
M OD-4
M
M
M OD -5
M
M OD -6
M
T hyristor
Bypass
#2
T hyristo r
Bypass # 1
SWDC1
Transmission bottleneck
at Marcy Substation
M
2x 100 MVA Convertible
Static Compensatora smart solution
NYPA’s Marcy Convertible Static Compensator
“Smart Technology” Relieving Transmission Bottlenecks
Relief of major transmission
bottleneck
Strong dynamic voltage
support at Marcy has resulted in
increase of transmission capacity
by about 200 MW, approximately
enough power for about 200,000
homes.
Introduction of unprecedented
“Smart” controllability and
flexibility in transmission grids
HVDC Transmission Technology
HVDC Converter Station
Up to 6400 MW
Overhead Lines
Two conductors
HVDC Converter Station
Up to 6400 MW
Alt.
Submarine cables
Thyristor
Thyristor
Investment Cost versus
Distance for AC and DC
Edris
AC versus HVDC – Right-of-Way
10000
HVDC
AC
1000
MW
Power transmitted
100
30
40
50
60
70
80
m
Right-of-Way Width
Edris
AC versus HVDC – Right of Way
Comparison of Towers for 800 kV AC Line a) and 500 kV DC Line b), at same Transmission
Capacity
3000 MW
AC
DC
Edris
DC versus AC Transmission Solution for System
Interconnection
With DC Solution, Interconnection Rating is determined only by the
actual Demand on Transmission Capacity
With AC Solution, for System Stability Reasons, AC Rating must be
higher than the actual Demand of Power Exchange
Increase in Power Transfer: with DC, Staging is easily possible
With DC, the Power Exchange between the two Systems can be
exactly determined by the System Operator
DC features Voltage Control and Power Oscillation Damping
DC is a Barrier against Stability Problems and Voltage Collapse
DC is a Firewall against cascading Blackouts
Predetermined mutual Support between the Systems in Emergency
Situations
Edris
HVDC Technologies
HVDC Classic – VSC HVDC (PLUS/LIGHT)
HVDC Classic
HVDC PLUS/LIGHT
Line-Commutated
current-sourced Converter (LCC)
Self-commutated
Voltage-Sourced Converter (VSC)
Thyristor with turn-on Capability
only
Semiconductor Switches with turn-on
and turn-off Capability, e.g. IGBTs
Main Differences in Features and Characteristics of
LCC HVDC and VSC HVDC
LCC HVDC
•
•
•
•
•
•
•
•
•
In service since 1954
Installed Capacity > 70 GW
Highest Voltage +800 kV
Requires adequate AC voltage
support for commutation
Requires large Filters
Converters absorb 0.5 Mvar for
each MW transferred (2-quadrant
control)
Large footprint
Lower power losses <1%
Reverse of power flow direction
requires change in DC voltage
polarity
VSC HVDC
•
•
•
•
In service since 1997
Installed Capacity 1GW
Highest Voltage +150 kV
Self commutated, no commutation
problem
• Smaller, high frequency filters
• Capable of both injecting or absorbing
reactive power (4-quadrant control)
• Smaller footprint
• Higher power losses>1.5%
• No change in the DC polarity
33
VSC Back-to-Back Concept
HVDC Light/HVDC Plus Technology
System 1
System 2
V1
V2
P12
+
+
Smart
Idea
-
-
B a c k -t o -B a c k A s y n c h r o n o u s /S y n c h r o n o u s T ie
Transm
ission
lineline
Transm
ission
VL
L
V0 V0
V dV
c dc
Transformer
Transformer
I I inducta
inductance
nce
Transm
ission
lineline
Transm
ission
VL L
V0 V0
Transformer
Transformer
I I inducta
inductance
nce
Voltage
Sourced
sourced
In verter
inverter
Voltage
Sourced
sourced
In verter
inverter
DC DC
capacitor
capacitor
DC DC
capacitor
capacitor
V dV
c dc
Segmentation with Grid Shock Absorbers
Proof of Concept
System 1
System 2
V1
V2
P12
+
+
D
-
-
B a c k -t o - B a c k A s y n c h r o n o u s /S y n c h r o n o u s T ie
E
Hydro
Quebec
Ontario
A
A
New
England
B
System 1
P12
+
+
-
-
B
New
York
System 2
V2
V1
D
B a c k -to -B a c k A s y n c h r o n o u s /S y n c h r o n o u s T ie
PJM
C
Outside World
C
Eastern Interconnection
Voltage supported buses
Segmentation with Grid Shock Absorbers
Proof of Concept
2003 Blackout
Lights on
An Excellent Application of VSC HVDC
Edris
Thanks for your attention
Q U A N TA
SERVI CES
Quanta Technology
Advancing the Grid
BGE
Dr. Aty Edris
January
4, 2008Advisor
Sr. Director
and Executive
aedris@quanta-technology.com
November 2007
Edris