Hi h T t S d tiHigh Temperature Superconducting...
Transcript of Hi h T t S d tiHigh Temperature Superconducting...
Hi h T t S d tiHigh Temperature Superconducting Transmission:
Losses and other Considerations
Dr. Michael Gouge, ORNL
GCEP Advanced Electricity Infrastructure Workshop
Stanford University
November 1, 2007
Superconductivity is not newp y
• Superconductivity discovered in 1911Superconductivity discovered in 1911 in the element mercury
• metallic superconductors (for magnets):magnets):– materials are NbTi, Nb3Sn
• operation in liquid helium– 4 K or -452 F – “low temperature superconductors”
• medical imaging (MRI) & research g g ( )magnets
• fusion and accelerator magnets
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Superconductors: Electricity p yflows without loss of energy
O di d t l tOrdinary conductor: electronsmoving at random lose energy in
collisions, generating heat.
Superconductor: electrons moving in pairs don’t collidein pairs don’t collide,
generating no heat and losingno energy!
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How Cold is Cold, and What is “High-Temperature?” g p
321-321
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The Electricity Chain
hydrowind solar digital
electronics
coalgas
heatmechanical
motion electricity
communication
power grid
transportationmotion
fuel cells lighting
grid
industrynuclearfission
fuel cells g gheating
refrigeration35% of primary energy
production delivery use
transportation petroleum chain ⇒ 29% of primary energy
Basic Energy SciencesBasic Energy Sciences Workshop on Superconductivity May 8Workshop on Superconductivity May 8--11, 200611, 2006
transportation petroleum chain ⇒ 29% of primary energy
The Great Enabler
% primary energy devoted to electricity production
30
40
20
30
%
10 QuickTime™ and aTIFF (Uncompressed) decompressor
are needed to see this picture.
1880 20201920 1940 1960 1980 20000.0
1900
Basic Energy SciencesBasic Energy Sciences Workshop on Superconductivity May 8Workshop on Superconductivity May 8--11, 200611, 2006
source: EPRI
DOE Superconductivity for Electric S t PSystems Program
– Develop & Demonstrate Equipment
• Transmission & Distribution– Power Cables– Transformersa s o e s– Fault Current Limiters
• Rotating Electric Machines– Generators (MVA)Generators (MVA)– Motors (HP)– Synchronous Condensers (MVAR)
• Magnets• Magnets– Medical Imaging– Separation & Processing
R&D
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– R&D
Potential to Impact Existing Technologies and Opportunities for Novel Applicationspp pp
• Significant efficiency benefits to the national electricity infrastructure.
HTS motor is 50% smaller and lighter
. . .and losses are cut in half
HTS cable carries 3-5 x the current
HTS transformers are non-flammable (do not use oil) and more efficient
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Transforming the Grid: Efficiency and Environment
deliveryproduction
deliveryuse
HTS cablesFraction of resistance
Preferred power flow routeLow impedance ⇒ easier regulation
HTS generatorsHigh power density ⇒ 1/2 size weight
Low impedance ⇒ easier regulation
HTS motorsHigh power density⇒ 1/2 size, weight
⇒ 1/2 size, weight
1/2 to 2/3 the losses
high efficiency down to 5% of
TransformersHigh power density ⇒ 1/2 size, weight h t ti
1/2 losses at high speedHigh efficiency at low
speed
the rated load
withstand voltage and reactive power fluctuations
⇒ cheaper construction
1/2 the losses
No flammable or contaminating transformer oil
Replacement of industrial motors could save 1% of total electricity use = 4
GW
Basic Energy SciencesBasic Energy Sciences Workshop on Superconductivity May 8Workshop on Superconductivity May 8--11, 200611, 2006
transformer oilSite in urban areas
Efficiency and Environment
electricityelectricityproduction electricity
deliveryelectricity
use
incandescent~ 5% efficient
Solid state> 50% efficient
Lighting ~ 22% of electricity use
51% produced from coal
63% primary energy lost
2 Gt CO2/yr
7-10% transmitted energy lost
= 40 GW
Clean electrical energy
electric motors ~ 64% of electricity use
2 Gt CO2/yr34% of CO2 emissions
Clean electrical energy
Contaminating and flammabletransformer oil
Urban restrictions on substationsTransportation 72% energy lost
Basic Energy SciencesBasic Energy Sciences Workshop on Superconductivity May 8Workshop on Superconductivity May 8--11, 200611, 2006
72% energy lost 31% CO2 emissions
High Temperature Superconducting (HTS) Generators: Modest efficiency savings but over a
large fraction of electricity generated
From final report: p“GE believes that the economic breakpoint for a utility class HTS generator will be a based loaded unit rated above 500 MW At these higherrated above 500 MW. At these higher ratings, the fixed costs, such asthe refrigeration and other auxiliary equipment, can be amortized over a greater efficiency benefit.”
• Typical efficiency savings for
GE 100 MVA HTS GeneratorDesign
Typical efficiency savings for larger units are 0.35-0.55%.• For a 575 MVA GE unit, the loss savings was 2 GW – 0.35%.
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Design
Cable cross-sectional view• Co-axial cable features:
– Magnetic field shielded (HTS outer shield).B th d t d
Liquid Nitrogen Coolant
Inner Cryostat Wall
Copper Shield Wire
Outer Protective Covering
Liquid Nitrogen Coolant
Inner Cryostat Wall
Copper Shield Wire
Outer Protective Covering
– Both conductor and dielectric are wrapped from tapes.
– Cryogenic dielectric reduces size and
Copper Core
High Voltage Dielectric
HTS Shield Tape
Coppe S e d e
HTS Tape
Copper Core
High Voltage Dielectric
HTS Shield Tape
Coppe S e d e
HTS Tape
reduces size and increases current carrying capacity.
– Flexible cable to allow reeling Outer Cryostat Wall
Thermal “Superinsulation”
Outer Cryostat Wall
Thermal “Superinsulation”
g• New tri-axial design is
most compact superconducting cable concept:– Minimizes use of HTS
tape– Requires minimum
surface area for cryostat-lower heat load
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lower heat load
HTS cables are attractive in niche applications like NYC to deliver high current (power) in a small duct spaceto deliver high current (power) in a small duct space• 9 three-phase copper circuits, each
in a 6 inch duct– copper conductors de-rated due to
heating in adjacent ducts• One three-phase tri-axial cable in 10
Copper
inch duct• At constant current can increase
capacity by increasing voltageHTS
William Street & Fulton
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William Street & Fulton Sreet, New York City
(2003)
HTS cables have loss reductions relative to copper d t b t th ibl k t i llconductors but the accessible market is small
• Transmission (~138 kV and above) ( )About 12 percent (160,000 miles) of all power lines are transmission lines.For most utilities, over 99% of transmission lines are overhead. An equivalent underground transmission line can cost 5 to 15 times the cost of an overhead transmission line but there is a growing market.g gHTS cables are now several times more expensive than copper underground cables so there only an incentive to install HTS cables in the transmission grid in niche applications or where there are strong aesthetic considerations.
• Distribution (~69 kV and below)Distribution ( 69 kV and below)About 88 percent of all power lines.Generally the capacity of these lines are low (less than 20 MVA) and the load factor variable so it is not attractive for HTS cables.There may be some applications for HTS cables at 35-69 kV and 2-4 kAThere may be some applications for HTS cables at 35 69 kV and 2 4 kA (100’s of MVA) but this market will not impact national grid losses much.
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Why HTS Transformers?• From power generation to end user there are 8-9% losses. Much
of this is in transformers.• 80% of losses in transformers are load loss, which HTS ,
application makes almost negligible.• Need for efficient delivery of electric power will continue to grow
world wide.
2000
2500
U.S. Power Transformers (10+MVA)
1000
1500
2000
Units
00
500
5 10 15 20 25 30
34,800
Age of Transformers in Years
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HTS Motors: Reduced losses in end use
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Superconductivity can reduce losses in ti t i i d dgeneration, transmission and end use
• The loss reduction is evaluated for the HTS component prelative to the copper or aluminum conductor it replaced.
• There is a cryogenic penalty which must be taken into account. Typically for 1 watt removed at 77 K it requiresaccount. Typically for 1 watt removed at 77 K it requires 10-12 watt of electrical input power at room temperature.
• The cryogenic losses are normally much less than the efficiency gain for larger devices This sets a thresholdefficiency gain for larger devices. This sets a threshold for HTS grid component size:– 100-300 MVA for HTS generators
10 20 MVA f HTS t f– 10-20 MVA for HTS transformers– ~5 MVA (6700 HP) for HTS motors
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General refrigeration cycleg y
H t j ti QHeat rejection Q hto ambient at T h
QFluid expansion to reduce
temperature Work done onprocess fluid
Power in via compressor or drive unit
QHX
Power produced and lost to ambient.
10-20 watt at 300 K
Heat absorptionQc watts at Tc
ch
cCarnot TT
T−
=η
HTS load at ~Tc ( ) Carnotreal .3-.1 ηη ×≈1 watt at 77 K
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Cycle efficiency vs. capacity at Top
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Typical cryogenic heat loads
Heat rejection Q hto ambient at T h
Q
Heat absorptionQc watts at Tc
Fluid expansionto reduce
temperature
Work done onprocess fluid
Power in viacompressoror drive unit
QHX
Power produced and lost to ambient.
HTS Component Heat load, Top C bl ( h ) 3 4 kW/k t 65 80 K
HTS load at ~Tc
Cable (per phase) 3-4 kW/km at 65-80 K
Transformer (10-100’s MVA) 100-1000 W at 60-80 K
Motors (5,000-40,000 HP) 50-100’s W at 50-65 K
Generators (400-1500 MW) 100-1000 W at 50-65 K
Fault Current Limiters ~ kW’s at 50-80 K
SMES, magnetic separation, 10-100’s W at 50-65 K
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MRI, etc.
Insert more efficient HTS i h i i idcomponents into the existing grid
• Analysis from EC and Japan:– Assign threshold component rating for HTS
t h l i ti (MW MVA HP)technology insertion (MW, MVA, HP)– Specify efficiency improvement taking into account
the cryogenic penaltythe cryogenic penalty– Assume a fraction of the total market is penetrable– Calculate annual energy savings in TWh– Convert to MMT of carbon dioxide (region specific)
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Results from EU StudyComponent Threshold
ratingLosses
relative to conventional
Annual Energy Savings
CO2 Reduction
Generator 100 MW 0.5 10.4 TWh
Transformer 12.5 MVA 0.5 20.7 TWh
Total 31 TWh 14.7 MMTTotal(1.2% of total generation)
(average over all generation)
(20% of Kyoto reqr.)
Teemu Hartikainen et al., “Reductions of greenhouse gas emissions by utilization of superconductivityin electric-power generation,” Applied Energy, 78, pages 151-158, (2004).
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Results from Japanese StudyComponent Threshold
ratingLosses
relative to conventional
Annual Energy Savings
CO2 Reduction
conventionalGenerator Efficiency
improved by 0.5%6.4 TWh 3.0 MMT
Transformer Efficiency improved by 0.125-0.25%
13.0 TWh 1.0 MMT
Motors 1 MW Efficiency 5 0 TWh 0 4Motors 1 MW Efficiency improved by 2%
5.0 TWh 0.4
Total 24.4 TWh 4.4 MMT
S. Morozumi, “Potential of energy conservation by superconductive applications,” Physica C, 357-360, pages 20-24, (2001).
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y , , p g , ( )
Results from Japanese Study: benchmark to U.S.
S Morozumi “Potential of energy conservation by superconductive applications ”
The multiples of contribution of superconductive applications to energy conservation andCO2 reduction in the USA are compared to Japan (Japan is defined as 1 in each case).
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S. Morozumi, Potential of energy conservation by superconductive applications, Physica C, 357-360, pages 20-24, (2001).
Insert more efficient HTS i h i i idcomponents into the existing grid
• Analysis for U.S.– Same general approach as EU, Japan– 4,055 TWh of electricity generated in 2005, y g– Assume 9.5% of generated electricity is lost (EIA 2006)– Assign threshold component rating for HTS technology insertion
(MW, MVA, HP)– Specify efficiency improvement taking into account the cryogenic
penalty– Assume a fraction of the total market is penetrable– Calculate annual energy savings in TWh– Convert to MMT of carbon dioxide (5.4 MMT/GW-year)
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U.S. Similar Approach
Component Threshold rating
Losses relative to conventional
Annual Energy Savings
CO2 Reduction
SavingsGenerator 400 MW Efficiency
improved by 0.4%13.0 TWh
Transformer 10 MVA Efficiency improved by 0.2%
25.6 TWh
5 MW Effi i 12 8 TWhMotors 5 MW Efficiency improved by 1.9%
12.8 TWh
Total 51.4 TWh 31.8 MMT (average Total ( gover all generation)
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R&D, energy savings and policy can accelerate insertion 3-4 HTS can accelerate insertion
• HTS Conductors– Optimize conductor design to meet grid applications
tapes carry the same current as this 400-A copper cableg g
– Reduce manufacturing costs an order of magnitude – Reduce ac losses
• Cooling systems– Lower cost: from $100 to $25/watt at ~ 65-80 K Pulse-tube
copper cable
– higher efficiency (20-30% of Carnot) and high reliability cryocoolers• High voltage/low temperature electrical insulation
materials– Dielectric materials that meet application needs
cryocooler
– Make cryogenic electrical engineering routine• DOE-Office of Electricity is supporting HTS R&D
and realistic grid demonstrations• Need an incentive for utilities and end users to
switch to HTS grid devices– Annual electricity savings is a start….– CO2 reduction credit?
R e s is ta n c eis fu t ile .
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Reconfigure the Gridoror
Was Edison right?
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Enable efficient, reliable two-way power flow via HTS DC cablesflow via HTS DC cables
• Since there are effectively no resistive losses, HTS DC cables can carry 10-100 t t th ti l
Conventional cable 300-1000 A
100 x greater current than conventional cables
• For fixed power in a range of 20-500 MVA, this allows the DC voltage to be
12 cm
, greduced from 100-150 kV to 10’s of kV
• This simplifies the converter station, reduces its volume and cost and increases the reliability of the DC
LN
increases the reliability of the DC network HTS Tapes
Dielectric
Vacuum/MLI
HTS dc cable 10,000-50,000 A
DC network with
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HTS backbones
HTS DC Cable: A potential solution for growing power delivery needs of computing facilities
• ORNL Leadership Computing Facility is advancing:Cray XT3 Jaguar – 250 TF in 2007
Motivation
– Cray XT3 Jaguar – 250 TF in 2007– Cray Baker – 1-PF in 2008– Expansion to “exa-scale” systems considered
• Expect significant increase in power demand (30 MW) facility upgrade neededdemand (30 MW) facility upgrade needed
• DOE is interested in addressing efficiency issues for data centers
• No resistive loss increase efficiency, reduce CO2 footprint.• Single high power density cable reduce footprint and
Benefits of HTS DC cable
Single high power density cable reduce footprint and environmental impact
• DC power ready to integrate with computers• Relocate auxiliary power equipment outdoors
d li i t i bl
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OAK RIDGE NATIONAL LABORATORYU. S. DEPARTMENT OF ENERGY
SSM_0609
reduce cooling requirement, increase usable space
North American Transmission RegionsEASTERN470 GW
103 control areas
Four major independent asynchronous networks, tied together only by DC interconnections:1. Eastern Interconnected Network – all regions east of the Rockies except ERCOT and Quebec portion of the NPCC reliability council.
Four major independent asynchronous networks, tied together only by DC interconnections:1. Eastern Interconnected Network – all regions east of the Rockies except ERCOT and Quebec portion of the NPCC reliability council.2. Quebec – part of the NPCC reliability council.3. Texas – the ERCOT reliability council.4. Western Interconnected Network – the WSCC reliability council.
2. Quebec – part of the NPCC reliability council.3. Texas – the ERCOT reliability council.4. Western Interconnected Network – the WSCC reliability council. Source: Arrillaga (1998)Source: Arrillaga (1998)
From the U.S. - Scientific American - July 2006 Paul Grant EPRIPaul Grant, EPRI
Cryogenic superconductingCryogenic, superconductingconduits could be connectedinto a “SuperGrid” that wouldsimultaneously deliver dc electrical power and hydrogen fuel….hydrogen fuel….
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Japanese vision: HTS dc and solar, wind farms
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Ryosuke Hata, Dr., Eng.Sumitomo Electric Industries, Ltd.ISIS-16
More details
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ConclusionsConclusions
• Substitution of conventional generatorsSubstitution of conventional generators, transformers and large motors with their HTS counterparts can:HTS counterparts can:– save up to 14.7, 4.4 and 31.8 MMT of CO2 in
EU Japan and U SEU, Japan and U.S.• Reconfiguration of the grid can save more
but requires a major paradigm shift inbut requires a major paradigm shift in technology and policy.
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Thank you yand
Extra slidesExtra slides
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• From T. J. Blasing 1 kW-hr = 605 g of CO2; for 1 year 5.3 MMT for 1 GW• 2005 total generation is 4055 106 GW-hr: average over year is 463 GW: produces 2330 MMT of g g y p
CO2 or 5.0 MMT/GW• T&D losses of 7-10% of generated power about 40 GW producing 230 MMT of CO2: for I year this
is 5.8 MMT/GW• 64% of energy generated in the US is converted by electric motors--approximately half of this is
converted by motors greater than 1,000 hp• About 70% of the 1000 horsepower and above motor market is a viable target for HTS motors.• An HTS motor will have half the losses (or less) of a conventional motor of the same rating. The
size of the HTS motor will also be smaller. Consider a 6000 horsepower motor example. The ti l hi h ffi i i d ti t ill b 96 6% ffi i t hil th HTS t ill bconventional, high efficiency induction motor will be 96.6% efficient while the HTS motor will be
98.5% efficient (including the power loss associated with the HTS coil cryocooler system as a loss for the HTS motor). This 1.9% efficiency improvement results in a savings for the customer approaching $50,000 per year.
• If $1 Billion of HTS motors are sold worldwide each year about one third of these sales would beIf $1 Billion of HTS motors are sold worldwide each year, about one third of these sales would be in the United States. Factoring in the energy efficiency improvement of the HTS motors over conventional motors, the $333 Million in HTS motor sales in the Unites States results in an annual savings (from this one year of motor sales) due to the efficiency improvement provided by HTS motors of $41 Million (about 0.6 Billion kW-hr at $0.07 /kW-hr). Taking a typical large motor life
f 25 d l k t diti th ti i t ll d b d f l t ill bof 25 years, under normal market conditions, the entire installed based of large motors will be replaced by HTS motors over a 25 year period. It is expected that this transition will be faster as energy costs continue to climb. With a conversion of all large electric motors that are candidates for HTS technology the annual energy savings, in the United States alone, will be over $1 Billion (25 years of motor sales adding at least an additional $41 Million in energy savings each
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( y g $ gy gyear).
• Energy losses in the U.S. T&D system were 7.2% in 1995, accounting for 2.5 quads of primary energy and 36.5 MtC. Losses are divided such that about 60% are from lines and 40% are from transformers (most of which are for distribution).
• The EIA estimates that transmission and distribution losses in the United States averaged about 9 percent of electricity generated in 2005.
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The Power Grid
6
5
4
TransmissionInvestment
4
3
2
1
$B
Source: Cambridge Energy Research Associates
200019801970196019501940 19900
capacity50% growth
reliabilityblackouts
efficiency / environment7-10% of power is lost in the grid
40 1GW l tsby 2030urban power bottleneck
cascadesquality
40 1GW power plants230 Mmt of CO2
Basic Energy SciencesBasic Energy Sciences Workshop on Superconductivity May 8Workshop on Superconductivity May 8--11, 200611, 2006
Blackouts, Cascading Failures, and Quality
Insufficient regional generationRolling blackouts west coast
Brownouts east coast400 major outages 1984-1999
Grid congestion preventspower sharing
Local failures cascade2003 Northeast Blackout
508 generators tripped outCleveland ⇒ Toronto ⇒ NYC1800400 major outages 1984-1999 Cleveland ⇒ Toronto ⇒ NYC
7 minutes
600
1000
1400Requests for Relief from Power Exchanges
Requ
ests
10/yr
ency
1996 1998 2000 2002
200
North American Electric Reliability Council
1/yr
1/10yrs
1/100yrs
Freq
ue
I t t d t t 2/3 it l t i lit diti i
Not only outages, but qualityCustomers affected
1/100yrs
10K 100K 1M 10M
Report on 2003 North American Blackout,
https://reports energy gov/
Report on 2003 North American Blackout,
h // /
Digital power quality: 10% demand today ⇒ 30% by 2020
Internet data centers: 2/3 capital cost is power quality conditioningSemiconductor fab lines need steady voltage to fraction of a cycle
https://reports.energy.gov/ https://reports.energy.gov/
Basic Energy SciencesBasic Energy Sciences Workshop on Superconductivity May 8Workshop on Superconductivity May 8--11, 200611, 2006
The grid cannot deliver digital quality power for the 21st century
Transforming the Grid: Superconducting Cable
5-fold more power than copper
same cross section
zero DC loss
100 f ld l C l h
Lower losses ⇒ longer transmission
Regional power sharingCross weather boundariesCross generation zones100-fold less AC loss than copper
high power density ⇒ small size
Cross generation zones
Generation at fuel source for distant transmission
Replace copper with superconductor
Use existing underground conduits
N Y k
HTS XLPE
XLPE
XLPE
138 kV
230 kV
345 kVLower voltageNo heatingNo impact on underground i f
New YorkCA
Transcontinental diurnal levelingIncrease efficiency and capacity
Only superconductors can achieve this HTS
XLPE
HTS XLPE
0 500 1000250 750
34.5 kV
69 kVinfrastructureEasier permitting
Basic Energy SciencesBasic Energy Sciences Workshop on Superconductivity May 8Workshop on Superconductivity May 8--11, 200611, 2006
0 500 1000250 750Power Capacity (AC 3Φ, MVA)
Transforming the Grid: Superconducting Power Control
Fault current limiters Reactive power controlFault current limitersManage overload currents due to lightning, wind, component failure, dynamic power flow
Growing complexity ⇒ growing fault currents age
Reactive power control
reactive loadtransformers
g p y g g
R l
Volt
aReal loadresistive
Superconductors:
smart fault control
The wire is the controller
Resi
stan
ce IcReal power
Driven by grid: motor
Superconducting reactive power regulator
The wire is the controller
Fault current limited in half cycle ~ 10ms
Fast automatic reset when fault is cleared
CurrentDr n y gr m t r
Injects/absorbs reactive power: generator
Smart dynamic responseFast automatic reset when fault is cleared
Transparent when not active
Superconductors enable smart self-healing grid
Small, economic packageFirst commercial
superconducting grid technology
Basic Energy SciencesBasic Energy Sciences Workshop on Superconductivity May 8Workshop on Superconductivity May 8--11, 200611, 2006
Superconductors enable smart self healing grid