Superconductors for Power Transmission and Distribution

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Superconductors for Power Transmission and
Distribution
Technology Engineering Division
Joseph V. Minervini Division Head, Technology and
Engineering Plasma Science and Fusion
Center Massachusetts Institute of
Technology PPPL Colloquium Princeton, NJ May
13, 2009
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Outline

• Background on superconductivity
• Electric power usage in the US and worldwide
• The Electric Power Grid
• Energy Losses
• Grid Congestion and Reliability
• Superconductors in the grid
• AC vs DC
• Summary

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• Superconductivity

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Discovery of Superconductivity (1911)
Heike Kamerlingh Onnes (1853-1926) Door meten
tot weten (Through measurement to knowledge)
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Resistance is a function of temperature
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Facts on Superconductors

• There are two groups of superconductors
• Low-temperature (metallic) superconductors
  (LTS)
• High-temperature (oxide) superconductors (HTS)

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Facts on Superconductors - Electrical Behavior
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Facts on Superconductors

• Three Critical Parameters
• Critical temperature, Tc
• Critical magnetic field, Hc
• Critical current density, Jc

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Type II Superconductors Display Magnetic
Hysteresis
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Progress of Tc
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J.V. Minervini - PSFC Seminar, February 20, 2009
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BSCCO Wire (1st Gen) is Expensive
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J.V. Minervini - PSFC Seminar, February 20, 2009
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YBCO Tape (2nd Generation-HTS)

• SuperPower (Latham, NY) uses a reel-to-reel
  system for tape production

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HTS Conductors
HTS versus Copper Equivalent current carrying
capacity
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• Electric Power Usage in the US and Worldwide

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J.V. Minervini - PSFC Seminar, February 20, 2009
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Human Development is Directly Related to
Electricity Use
Source Global Energy Futures and Human
Development A Framework for Analysis, Alan D.
Pasternak, LLNL Report, UCRL-ID-140773 (October
2000)
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GDP and Energy per Capita are Related
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Energy consumption by 2025 is expected to more
than triple from 1970 levels
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J.V. Minervini - PSFC Seminar, February 20, 2009
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United States Electric Grid
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North American Electric Grid
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Total Electrical Energy Supply and Loss in the
Transmission and Distribution Systems(per annum,
24 member countries)

• Energy losses in the U.S. TD 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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• Electric Grid Congestion
• and Reliability

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New Transmission Capacity is Critical

• Electricity demand is far outrunning expansion in
  transmission capacity
• Transmission line investment is decreasing yearly

Source Karl Stahlkopf, Vice President, Power
Delivery, EPRI, Presentation at University of
Wisconsin, October 20, 2000
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Major Congestion Corridors
From DOE Congestion Study, 2006
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Need for Fault Current Limiters

• Accidents do happen

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Northeast Blackout - August 14, 2003

• Impact
• Over 50 million people
• 60-65,000 MW
• 30 hours to restore
• Manufacturing disrupted
• 400 Generators tripped
• Statistics
• Line trips began at 305 PM
• Cascading began at 406 PM
• Lasted approximately 12 seconds
• Thousands of discrete events

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• Electric Utility and Power Applications
• Of Superconductivity

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Three Major Challenges for Electric Power

• Increase transmission capacity
• Superconducting AC and DC transmission lines
• Increase system stability and reliability
• Superconducting fault current limiters (SFCL)
• Superconducting Magnetic Energy Storage (SMES)
  for energy storage and system stabilization
• Superconducting machines running as synchronous
  condensors for system stabilization and VAR
  compensation
• Increase system efficiency and safety
• Superconducting transformers

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Visions of A Superconducting Grid

• Efficiency
• Energy sector and transmission losses waste 300
  TWh (equivalent to 400 million barrels of oil)
  per year
• Environment
• Superconducting transmission lines require
  1/3-1/4 as much tunneling/trenching as copper

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Grid 2030 Vision
Superconducting systemsare seamlessly
integrated with high voltage direct current
systems and other advanced conductors for
transporting electric power over long distances.
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Proposed Configurations for HTS AC Cable
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Warm Dielectric HTS Cable
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Cold Dielectric HTS Cable
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Advantages of HTS Over Conventional Cables

• HTS gt 3 x current density of conventional cable.
  HTS also permits a smaller overall diameter,
  because of the absence of a need for heat
  exchange to the air or ground. The size and
  current advantages lead to
• Reduced investment cost by reducing
  infrastructure and right-of-way costs HTS
  coaxial cable is smaller than conventional cable.
  For underground transmission 3-4 x more power
  can be carried by HTS than copper cables in
  trenches and tunnels.
• Reduced substation costs by delivering power at
  lower voltages.
• The lower weight of HTS allows quicker and less
  expensive deployment by lower tension cable
  pullers, smaller spools, cheaper transport, and
  reduced mechanical support.
• Possible deployment in existing infrastructure
  not currently used for conventional cable,
  including commuter lines, light rail, subways,
  auto, railroad and sewer tunnels, overhead
  highways and bridges.

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Advantages of HTS Over Conventional Cables
(contd)

• HTS DC cable carries only real power, not
  reactive power, thus avoiding significant
  derating of the cables.
• Low radiated EMF due to self-shielding design.
• Increased system reliability because of more
  flexibility in siting new capacity, more
  overcapacity leading to fewer outages, no
  temperature excursions during normal operation.
  Cold operation leads to longer insulation life.
• Better control of power flow by using phase angle
  regulators in series with a much lower impedance
  HTS cable

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HTS Cables Can Increase Power Insertion to
Congested Urban Areas Through Retrofit in
Existing Tunnels
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Albany Cable Project (SuperPower)
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Albany HTS Cable Project

• Delivery of nearly 10,000 m of 2G wire for the
  Albany HTS Cable Project
• Worlds first 2G device

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AEP-Southwire/Bixby Cable Project (SuperPower)
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System Reliability

• Superconducting Fault Current Limiter (SFCL)
• HTS Fault Current Limiters (FCLs)
  cost-effectively correct fault current problems
  at the transmission voltage level of 138kV and
  higher
• HTS FCLs reduce the available fault current to a
  lower,safer level so existing switchgear can
  still protect the grid

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ZENERGY Fault Current Limiter
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ZENERGY Fault Current Limiter
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• AC vs DC

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DC Superconducting Transmission Line

• Advantages
• No DC resistive losses
• No AC inductive storage - carries only real
  power, no reactive power
• No AC losses
• Long range transmission of high currents,
  including undersea
• Very high power ratings including transmission of
  several GVA
• Fault currents limited by fast acting inverters
  at AC/DC and DC/AC ends of the line
• Low voltage transmission, if desired, limiting
  the need for high voltage transformers
• Simplified cable design, more amenable to using
  HTS tape geometry
• Cable coolant also used to cool solid state
  inverters increasing capacity and reducing high
  temperature aging degradation
• Disadvantages
• Invertors can add substantially to cost
• Most electric power grid infrastructure is AC

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AC versus DC Transmission

• HTS cables can carry 10 - 100 x greater current
  than resistive cables
• This allows transmission voltage to be reduced
  from 100s kV to 10s kV for similar power
  ratings
• This results in a simpler converter station, with
  reduced volume and cost and increases network
  reliability

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Alternative HVDC Connections
Back-to-Back
Long Distance
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North American Transmission Region
4 independent asynchronous networks tied together
only by DC interconnections
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AC versus DC Overhead Transmission
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HTS DC Applications

• HTS DC increases efficiency for long distance
  transmission
• Opens other advanced technology opportunities
• Direct connection of alternative low-carbon or
  carbon-free power sources
• Wind
• Solar PV
• Fuel Cell
• Microturbine
• other
• Connection of advanced energy storage devices
• Flywheel
• Battery
• Supercapacitor
• Superconducting Magnetic Energy Storage (SMES)
• other

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Off-Shore Wind Farm Power Transmission Using
HTS DC Cable
DC-to-AC Power Conversion
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Solar Photovoltaic Power Transmission Using HTS
DC Cable
CSP
Solar PV
Transmit DC before conversion?
Solar and Wind
DC Power
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A National Supergrid?
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Continental Superconducting Grid (Chauncey
Starr, EPRI)
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Where is it Windy?

• Trees and Hills, Matter

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How Far Away?

• Trees and Hills, Matter

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Wind in Space and Time
Source Mass Renewable Energy Trust TrueWind
Solutions
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Solar in Space and Time
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Summary

• The US and the world will need major new electric
  power system infrastructure to satisfy growing
  demand for energy and human development
• Superconducting technology can help meet this
  demand while
• Conserving energy
• Reducing emissions of GHG
• Increasing system stability and reliability
• Tying together distributed power sources like
  solar and wind
• This new superconducting technology will include
• AC and DC transmission and distribution lines
• Generators, motors, and synchronous condensors
• Transformers
• Superconducting magnetic energy storage
• A visionary SuperGrid could lead to an integrated
  system of large scale distribution of both
  electricity and hydrogen

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Experimental Device in Chubu UniversityFirst
Demonstration of HTS DC Tranmsission
Parameters current gt 2.5 kA voltage gt 20 kV
length 20 m Sumitomo Bi-2223 cable coolant
LN2 equipped with pump and cryogenic cooler
72 K - 77 K
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BSCCO High Voltage DC Cable
CASER-Chubu University, Japan, 20m experimental
cable
Photo of cross-section

• made by Sumitomo