New Transmission Options Case Study Superconductor Cables · The challenge of moving renewable...
Transcript of New Transmission Options Case Study Superconductor Cables · The challenge of moving renewable...
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Transmission Policy InstituteSheraton Downtown — Denver, Colorado
April 20-21, 2011
New Transmission Options – Case StudySuperconductor Cables
What is a Superconductor?
• Superconductors 100/25
• Superconductors are materials that exhibit unique electrical characteristics:
- Little to no resistance to the flow ofelectricity
- Ability to carry hundreds of times as muchelectrical current as copper
- Repel magnetic fields
• These characteristics require:
- Cooling below a critical temperature
- Current levels below a critical current
• Above these critical levels the material “quenches”, and current must flow elsewhere
• New, ceramic high temperature superconductor (HTS) material discovered in 1986
- Requires less cooling; cost effective liquid nitrogen may be used
Development of HTS has enabled utility commercial applications
Current
Capacity
Equivalents
Superconductor Cable’s ELECTRICAL Characteristics
• Very high power transfer capability compared to
conventional cables solves many siting problems
• Very low impedance reduces loading on parallel lines
and equipment
• Minimal magnetic field and elimination of heat
simplifies placement concerns, minimizes right-of-way,
and is easy on the environment
• Optional HTS cables with fault current management
capabilities eliminate need to upgrade existing equipment
HTS Cables offer unique capabilities
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Superconductor Cables Driving to Commercial Adoption
Dozens of successful HTS cable projects globally in service or in process
2001 2002199919981997 2010 2011 201320122000 2009200820072006200520042003
US/DTE – 24kV (120m)
US/EPRI – 115kV (50m)
DENMARK – 36kV (30m)
CHINA – 35kV (30m)
JAPAN – 66kV (30M)
US/Southwire – 12.5kV (30m)
KOREA – 22.9kV (30m)
US/Nat. Grid – 34.5kV (400m)
JAPAN – 77kV (500m)
SPAIN – 10kV (30m)
US/AEP – 13.8 kV (200m)
CHINA – 10.5kV (75m)
US/LIPA Phase I – 138kV (600m)
KOREA – 22.9kV (100m)
MEXICO – 15kV (30m)
CHINA – 110 kV (30m)
KOREA –22.9kV (100m)
RUSSIA – 35 kV (30m)
Powered by AMSC wire
Powered by other wire
JAPAN – 66kV (250m)
SHANGHAI PROJECT (SECRI)
US/ConEd – 13.8 kV (220m)
US/LIPA Phase II – 138 kV (600m)
KOREA/KEPCO – 22.9kV (500m)
SPAIN – 20kV (30m)
KOREA/KEPCO – 154kV (100m)
Project list updated 4-2010
US/TresAmigas-200kVdc(10km)
Undecided
China/SGCC– 110kV (1km)
Korea/KEPCO – 154kV (1km)
Korea – 22.9kV (3km)
Key HTS Cable PHYSICAL Characteristics
Familiar Physical Characteristics
• Looks like conventional cable
• May be spliced
• May be placed in ducts or direct buried
• Must be cooled with liquid nitrogen
• No thermal constraints for placement
HTS Cables offer unique capabilities in a familiar package
Unique Electrical Characteristics
• Very high power transfer capability
• Very low impedance
• Minimal magnetic field
• Elimination of heat
• HTS cables with fault current management
Power Transfer Equivalency of Superconductor Cables
Superconductor cables provide transmission-level power transfer at medium voltage
* No XLPE cable de-rating factors applied. Superconductor rating based on conventional 4000A breaker rating
0 200 400 600 800 1000
13.8kV
34.5kV
69kV
138kV
230kV
345kV
Power Transfer Capability - 3-phase MVA
XLPE
XLPE
XLPE
XLPE
XLPE
XLPE
HTS
HTS
HTS
HTS
• Same Voltage, More Power
- Greatly increased power transfer capacity at any voltage level
• Same Power, Lower Voltage
- New MV versus HV Siting Opportunity
• “MV Transmission”
• Ideal for NIMBY & ROW sparse environments
Simplifying Transmission Siting
HTS Cables Offer New Options to Siting Power Lines
Photo courtesy Consolidated Edison
One MV HTS Cable can replace:
• Many conventional underground
circuits
• Overhead transmission line
Background
Holbrook Superconductor
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LIPA is a NYS Authority established in 1998 as the primary electric service provider for LI1207 sq. mi. (roughly 100 miles by 12 miles)
Nassau, Suffolk and the Rockaway Peninsula
Population of about 3 million1.1 million residential customers
100,000 commercial customers
Since 1998, 5.7% population growth (172,000 more people)
$2.0 billion invested in system upgrades and improvements
LIPA owns the assets All T&D operations and most IS systems are outsourced
LIPA
LIPA Transmission System
LIPA Long Term Needs
Must meet increasing power demands in existing ROWs
Load continues to increase
LIPA expects 1200 MW of new load by 2020 - Major transmission reinforcements
will be required
Project Provides Potential Tool to Meet LIPA’s Long Term Needs
ROW Congestion - HTS Cables provide increased power transfer capability
within existing ROWs (2 - 5 times the capacity in the same space)
Overhead Permitting Problems
Potential cost savings compared to upgrading to 345 kV transmission
system
Site Specific
East / West transfer capability increase required by upcoming power
insertions
Why was LIPA Interested in a
Superconductor Cable?
Land and Route
Holbrook Substation
Port
Jefferson Shoreham
Wading
River
Miller
Place
Terryville
CentereachSuperconductor
Superconductor Example: 138 kV, 575MW Capacity
4 ft ROW
200 ft ROW
• Self contained thermal envelope No thermal de-rating
• Minimal magnetic field No parallel line de-
rating• Lower Impedance
Longer practical distance
Superconductor Cables Simplify Placement and Offer New Options to Siting Lines
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Long Island Power Authority Cable System
• Energized in April 2008
• World’s first HTS transmission voltage cable system in the grid
• Longest, most powerful superconductor cable in the world
• Able to carry 574 MW of power in a four-foot-wide right of way
• Landmark cable installation proving high power, transmission level applications
Over 15 years of HTS Cable Experience
Next Step??
Holbrook Superconductor
Proposed Future Project
Required to Support East/West Power Flows
Extend 138kV superconductor cable to meet future transmission
requirements
Located between Holbrook and Central Islip substations (6.2 miles)
Originally planned for summer 2012 – delayed
due to lower load growth
ALL underground; eliminates need for
conventional overhead-underground hybrid
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Present Status and Future Direction of HTS Power Application in KEPCO
Y o u n g - J i n W O N
P o w e r G r i d P l a n n i n g T e a m , K E P C O
Large Capacity & Low loss + Eco-friendly
HTS Cable & SFCL
High cost for Civil works
Difficulty of excavating roads for const’n conduit or culvert
NIMBY for the construction of new substations
To cope with continuous increasing of fault current
Countermeasures to renew the aged power cables
Ⅱ. Why ? HTS System in KEPCO ?
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Supplying the huge buildings with electric power by HTS cables
Replacing 22.9kV conventional cables(2~3lines) with the superconducting
cables using the existing conduit or culverts without additional civil works
22.9 kVSW/S
22.9 kV Superconducting Cablesto replace 154 kV conventional cables
~
154 kV S/S in the suburbs
SFCL
SFCL
SFCL
22.9 kVSW/S
22.9 kV Superconducting Cablesto replace 22.9kV conventional cables
Superconducting Transformers
22.9 kVSW/S
Downtown Area
Circuit Breaker(Normal open)
Superconducting Power System (SPS) applying distributed switching stations
for metropolitan areas
Apply superconducting power devices (cables, transformers, FCLs) to real power system
154kV transmission power system 22.9kV superconducting power system
Replace 154kV substations in downtown with 22.9kV underground switching stations
Replace 154kV conventional cables with 22.9kV superconducting cables
Bulk power transfer by superconducting cables and transformers & Fault current reduction by SFCL
Skip substations
Reduce construction costs
Environment-friendly
Avoid civil petitions
154kV
S/S
154kVS/S
154kVS/S
154kV
S/S
Downtown
154kV conventional cables
154kV
S/S
154kV
S/S
22.9kVSW/S
22.9kVSW/S
22.9kVSW/S
22.9kVSW/S
22.9kVSW/S
22.9kVSW/S
22.9 kVSuperconducting cables
Downtown
154kV conventional cables
SuburbSuburb
One of solutions for the site problem
No substations & Compact size Easy to find a site for power facilities in downtown
Underground switching stations Make a park on the switching stations
Economic benefits
Reduction of cost for buying land
The site for 22.9kV switching stations is less than 30%, compared to 154kV substations.
No additional construction cost
We can use established underground facilities such as existing electric power conduit pipes.
Environmental and social benefits
Environment-friendly Avoid the trend of NIMBY
No oil for cooling the system
Free of the explosion danger (Superconducting transformer)
No additional construction Reduce the construction cost and ease traffic congestion
High efficiency and loss of superconductor Save energy and reduce CO2 emission
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DC Superconductor cables for long distance
transmission
Superconductor Advantages with DC Power
• When carrying DC current, superconductors themselves
are perfectly lossless
- Regardless of length
- Regardless of power rating
• Benefits
- No power limitations based on current-based losses
- Allows lower voltage, higher current transmission
- Allows underground construction
Superconductors open the door for a true underground transmission system
Superconductor PowerPipes™
Superconductor PowerPipes combine:
• Superconductor cables
• DC power transmission
The result:
• A high capacity electric transmission “pipeline”
that is:
Underground and easy to site
Highly efficient
Offers greater security than other technologies
Provides for multiple power on- and off-ramps
The challenge of moving renewable power long distances needs another option
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Today’s Key Energy Challenge: Carrying 100’s of Gigawatts of Green Power to Market
Many Issues
• Multiple Sources
• Multiple Destinations
• Cost Allocation
• Siting
• Transmission Across
Interconnections
• Losses
AC Overhead Transmission
• Higher power and longer distances require higher
voltages
• Losses
• Limited power flow
control
• Power transmission
characteristics
• Public opposition
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0.0
1.0
2.0
3.0
4.0
5.0
0 200 400 600 800 1000
Po
wer
Tra
nsfe
r C
ap
ab
ilit
y,
GW
Line Length in Miles
Transfer Capability Versus Distance of a 765 kV Overhead Line
0%
2%
4%
6%
8%
10%
12%
14%
16%
100 200 300 400 500 600 700 800 900 1000
% L
os
se
s (E
st.
)
Miles
5GW of Renewable Energy Transmission
Range of Losses for Various 765kV Overhead Line Designs
Courtesy Argonne National Lab
Dominant form of transmission, but
many challenges
Existing Transmission Options
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AC
Point-to-
Point
HVDC
Multi-
terminal
VSC
HVDC AC
Point-to-
Point
HVDC
Multi-
terminal
VSC
HVDC
Multi-Terminal
Superconductor
Pipeline
Low Power (<1GW) Short (<100 mile) lines
Low Power (<1GW) Moderate (100-400 mile) lines
Low Power (<1GW) Long (>400 mile) lines
Moderate Power (1-5GW) Short (<100 mile) lines
Moderate Power (1-5GW) Moderate (100-400 mile) lines
Moderate Power (1-5GW) Long (>400 mile) lines
High Power (>5GW) Short (<100 mile) lines
High Power (>5GW) Moderate (100-400 mile) lines
High Power (>5GW) Long (>400 mile) lines
SUITABLE TRANSMISSION SOLUTIONS
Overhead Solutions Underground Solutions
TRANSMISSION LINE POWER AND DISTANCE
REQUIREMENTS
No suitable solution for high power, long distance, underground transmission
HVDC Superconductor Cables
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AC
Point-to-
Point
HVDC
Multi-
terminal
VSC
HVDC AC
Point-to-
Point
HVDC
Multi-
terminal
VSC
HVDC
Multi-Terminal
Superconductor
Pipeline
Low Power (<1GW) Short (<100 mile) lines
Low Power (<1GW) Moderate (100-400 mile) lines
Low Power (<1GW) Long (>400 mile) lines
Moderate Power (1-5GW) Short (<100 mile) lines
Moderate Power (1-5GW) Moderate (100-400 mile) lines
Moderate Power (1-5GW) Long (>400 mile) lines
High Power (>5GW) Short (<100 mile) lines
High Power (>5GW) Moderate (100-400 mile) lines
High Power (>5GW) Long (>400 mile) lines
TRANSMISSION LINE POWER AND DISTANCE
REQUIREMENTS
SUITABLE TRANSMISSION SOLUTIONS
Overhead Solutions Underground Solutions
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Fit of DC superconductor cables for underground, long distance, high power, multi-terminal transmission
Operational Opportunities for DC Superconductor Cables: ELECTRICAL EFFICIENCY
• Converter losses 2%, cooling losses 22kW/km
• Overall losses 2.75% for 5GW @1600km (2.4% for 10GW)
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0%
2%
4%
6%
8%
10%
12%
14%
0 100 200 300 400 500 600 700 800 900 1000
Lo
ss
es
(%
of
5G
W)
Length (miles)
Losses for 5GW Transmission
765kV OH, 2 Lines
765kV OH, 3 Lines
+/-300kV Underground DC [6]
Overhead +/-800kV DC [7]
+/-200kV Superconductor Pipeline
Optimized 765kV, 3 Lines [8]
Loss advantage increases with distance and MW rating
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Rights of Way Already Exist for Superconductor Electricity Pipelines
Cost Analysis
• 5GW, 1000 mile Superconductor DC Cable
System
- US$8.8 Million/mile two pole cable
- Costs include DC terminals, refrigeration, installation
- Doubling capacity to 10GW increases cable cost by
only 50% (extra converters not included)
• Cost Competitive with EHV AC
- US$2.5 - $5.5 Million/mile
- 2 to 3 lines needed for same capacity
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Long distance, high power superconductor DC cables
are cost competitive with EHV AC lines
Advantages of DC Superconductor Cables
• Highest power capacity
• Highest efficiency (lowest power losses) of any transmission technology
• Ideal for very long distances
• Capable of transferring power across the three U.S. interconnections
• Able to accept power from multiple distributed sources, and precisely deliver power to multiple distributed destinations
• Underground construction with minimum right of way requirement
• Simplified cost allocation due to precise controllability of DC terminals
• Minimizes interaction with existing AC grid, reducing costs and increasing operational flexibility
• Cost competitive
DC Superconductor PowerPipes are uniquely and ideally suited to move renewable energy to distant load centers
Tres Amigas SuperStation Project
Western
Interconnection
Eastern
Interconnection
Texas
Interconnection
Unique 3-way DC project to link the three U.S. Interconnections
Tres Amigas Project to Use Superconductor Electricity Pipeline
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Summary
AC and DC superconductor cables offer
new option for high power, underground,
transmission of electric power
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Transmission Grid of the Future