The New Superconductors - Proposed Applications

The New Superconductors 1

The New Superconductors- Proposed Applications

Presented atIEEE Award Dinner Night

New York City5 October 2011

IEEE Award Dinner – NYC- 20111005

Dr. Swarn KalsiKalsi Green Power Systems, LLC

Princeton, NJ [email protected]

Ph: 609-356-0600

mailto:[email protected]

The New Superconductors 2

Types of SuperconductorsOld and New Temperature Superconductors

OLD – Low temperature (~4K)LTS

• Conductor Types– NbTi - operate at ~4.5K– Nb3Sn – operate at ~ 4.5K

• Applications– MRI– High field magnets– Particle accelerators– Fusion

NEW – High Temperature (>20K)HTS

• Conductor Types– BSCCO-2212 – operate at 4-20K– BSCCO-2223 – operate at 30 -77K– YBCO-123 coated - operate at 30 -77K– MgB2 - operate at 10-20K

• Applications– All LTS applications– Power cables – AC and DC– Power transformers– Fault current limiters– Rotating machines– Maglev


….. But, they all need low cost and reliable refrigerators

3

Current Status of HTS - I• High cost of HTS is the major challenge for applications in

commercial devices• Rising commodity prices have adversely impacted HTS

commercialization– First Generation (1G) superconductors (BSCCO-2212 and -2223) employ

large quantity of silver that has seen price inflation of 5X during the last decade

– Only limited performance improvements during the last 5 years

• Second Generation (2G) superconductors (YBCO-123 Coated) do not employ much noble metals but have manufacturing issues– 2G materials made by plasma sputtering have better performance but are

more expensive– 2G materials made by film coating have lower performance but are less

expensive– However, both materials are still too expensive and a price reduction of 5-

10X (from the current prices) is needed for manufacturing economically attractive devices

– Manufacturers wish for more demand to drive down the price and equipment developers wish for significantly lower prices prior to prototyping new devices

• Both 1G and 2G are manufactured only in tape form

IEEE Award Dinner – NYC- 20111005 The New SuperconductorsCourtesy AMSC

Courtesy AMSC

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Current Status of HTS - II

• Magnesium Diboride (MgB2)– This is the latest addition to the HTS category– Practical applications of this material are in the 5-15K temperature range– A potential feature of this material is the expected much lower cost than the 1G and 2G

conductors– This material is manufactured in both rectangular tape and circular wire forms– MgB2 material is least developed and is not yet ready for application in commercial

devices

IEEE Award Dinner – NYC- 20111005 The New Superconductors

Courtesy HyperTech

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Cooling System• All commercial applications require low cost highly reliable

cooling systems for maintaining HTS at their desired operating temperatures

• Generally cost and reliability are inversely proportional to the operating temperature; i.e. lower temperature refrigerators are more expensive and require more maintenance than the higher temperature refrigerators.

• Lower temperature refrigerators also require more power to remove each watt of loss from the low temperature.

• Some of the possible cooling options are;– Gifford-McMahon refrigerators – available in modular form but are

expensive and require frequent maintenance.– Pulse tube coolers are expected to be more reliable but are still

expensive and are not available in larger sizes– Stirling coolers are expected to be most reliable and affordable but are

not yet available for operating temperatures below 60K– Reverse Brayton cycle refrigerators are only economical for larger

systems


Courtesy Cryomech

Courtesy Stirling Cryogenics

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Applications – Power Cables

• Power Cable – AC and DC– Both medium and high voltage cables

have been successfully prototypes and have been operating in active grid for several years

– High costs of HTS and cooling system are major obstacle to wide adaption


138kV, LIPA13kV, AEP

Courtesy AMSC/NEXANSCourtesy ULTERA

Superconductor Applications 7

An Alternative ApproachEmploy resistive aluminum cable now and upgrade to HTS later

• GE developed* an aluminum cable cooled with liquid nitrogen during the 1970s.

• Because of high cost of HTS today, it may be possible to install resistive cables now and upgrade them to HTS when its price drops down to a more economical level.

• Resistive cable are made using existing cable manufacturing machinery


* S.S. Kalsi, ”Applications of HTS to Electric Power Equipment”, Wiley, 2011Sumitomo, Albany, NY HTS cable

GE Resistive aluminum cable

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Applications – Power Transformer

• Only 2G materials are suitable for manufacturing HTS transformers

• ½ size and weight of the conventional transformers are the two key attractive features

• A few prototypes are under development around the world

• The biggest challenge is withstanding 2-sec short-circuit fault at the transformer terminals

• Also ‘point on the wave switching scheme’ is required for minimizing in-rush transient currents


Courtesy Waukesha Electric

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Applications – Fault Current Limiters (FCL)

• FCL take advantage of the following HTS characteristics:– Very low resistance under normal

operation– Very high resistance during high

current transient• Several prototypes have been built

around the world but none commercialized due to the following reasons:– Sufficient time (>30sec) must be

allowed following a fault clearance before re-inserting a FCL in the circuit

– High costs of HTS and cooling system are still of serious concern.


Coils in Series Rods in Series

Saturable Reactors in Series

Courtesy Siemens Courtesy NEXANS

Courtesy Zenergy

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Applications – Rotating Machines• HTS are employed only in

the field winding• High field capability of HTS

allows to reduce size and weight of slow speed machines by ~5X

• Large machines (36MW @120-rpm) have been successfully demonstrated

• Large wind turbine generators (10MW @10-rpm) employing HTS field winding are under consideration worldwide

• Challenge – High costs of HTS and cooling system


36MW motor on test bedCourtesy AMSC

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Summary

• Wider use of HTS superconductors in commercial devices require– Low cost superconductors– Low cost and reliable cooling systems

• HTS technology is ready for large scale commercial applications

Reference:‘Applications of High Temperature Superconductors to Electric Power Equipment’, Swarn S. Kalsi, Wiley/IEEE, ISBN 978-0-470-16768-7


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The New Superconductors - Proposed Applications