The New Superconductors - Proposed Applications

IEEE Award Dinner – NYC- 20111005

Presented at IEEE Award Dinner Night New York City 5 October 2011

Dr. Swarn Kalsi Kalsi Green Power Systems, LLC Princeton, NJ 08540 [email protected]

Ph: 609-356-0600

The New Superconductors

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Types of Superconductors

Old and New Temperature Superconductors

OLD – Low temperature (~4K) LTS NEW – High Temperature (>20K) HTS

• Conductor Types – NbTi - operate at ~4.5K

– Nb3Sn – operate at ~ 4.5K

Applications – MRI – High field magnets – – Particle accelerators Fusion • 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 IEEE Award Dinner – NYC- 20111005 ….. But, they all need low cost and reliable refrigerators

The New Superconductors

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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 Superconductors

Courtesy AMSC Courtesy AMSC 3

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 4

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 IEEE Award Dinner – NYC- 20111005 Courtesy Cryomech

The New Superconductors

Courtesy Stirling Cryogenics 5

Applications – Power Cables

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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

13kV, AEP 138kV, LIPA

Courtesy ULTERA IEEE Award Dinner – NYC- 20111005

The New Superconductors

Courtesy AMSC/NEXANS 6

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An Alternative Approach

Employ 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 GE Resistive aluminum cable Sumitomo, Albany, NY HTS cable * S.S. Kalsi, ”Applications of HTS to Electric Power Equipment”, Wiley, 2011 IEEE Award Dinner – NYC- 20111005

Superconductor Applications

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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 IEEE Award Dinner – NYC- 20111005 Courtesy Waukesha Electric

The New Superconductors

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Applications – Fault Current Limiters (FCL)

Courtesy Siemens Courtesy NEXANS • • 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.

IEEE Award Dinner – NYC- 20111005

Coils in Series The New Superconductors Rods in Series Saturable Reactors in Series

Courtesy Zenergy 9

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 bed IEEE Award Dinner – NYC- 20111005

The New Superconductors

Courtesy AMSC 10

Summary

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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

IEEE Award Dinner – NYC- 20111005

The New Superconductors

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