Superconductivity UK - Diboride Conductors Ltd.

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15 Νοε 2013 (πριν από 3 χρόνια και 4 μήνες)

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Superconductivity UK

Dr. Philip Sargent, Diboride Conductors Ltd.

Commercial superconductors,
Cryogenics and Transformers

This Talk


Materials Review and price predictions


BSCCO


MgB2


YBCO


Cryogenics considerations


Superconducting Transformers


Commercial Wire & Tape


Commercial production:


Niobium alloys

(NbTi, Nb
3
Sn etc)


B2223

/ silver tape
-

1
st

Generation HTS


Pre
-
commercial:


MgB
2


Industrial laboratory:


YBCO

2
nd

Generation HTS “coated conductor”



Key issues for power applications


Overall current density
J
e

of conductor, not
just of superconductor


Performance in field


Multiple filaments for
AC applications


Anisotropy of
J
c
with
respect to field
direction


Cost!


Conductor itself


Cooling (AC losses)


Scalability of
fabrication


Mechanical


Strength, bend radius


HTS

perovskite ceramics

Cu

O

Ba

Y

Ba

YBCO
-

YBa
2
Cu
3
O
7


B2223
-

Bi
2
Sr
2
Ca
2
Cu
3
O


Engineering Implications


Requires near
single
-
crystal microstructure

by complex processing,


Oxide requires furnace treatment in
controlled oxygen atmosphere, in silver,


Highly anisotropic resulting tape:


Along and across tape,


Sensitive to magnetic field direction!


AMSC & Sumitomo


AMSC &
Sumitomo have a
reciprocal licensing
agreement

American Superconductor 55 filament
(B2223) tape

Sumitomo (B2223) tape

AMSC B2223 Manufacturing Plant


Larger billets, Process automation, Longer
strands, Multi
-
dies, Faster line
-
speed,
Combination of process steps


Began volume production in early 2003


Full capacity could be 20,000 km/year, now
900 km/year







How much does it cost to buy the wire to carry
1000 Amps a distance of 1m?


Copper:
6 $/kA.m


22 $/kA.m

depending on
current density (400


100 A/cm
2
)


Superconductors typically quoted at J
c

and at 77K
and either zero magnetic field or “self field”.



Cryogenic OFHC copper can be 0.06 $/kA.m.


NbTi is approx. 0.9 $/kA.m in liquid helium.

Price/Performance $/kA.m

Reduced Manufacturing Costs ($/m)
and

Increased Wire
Performance (current carrying capacity)

1995

1996

1997

1998

1999

2000

2001

2002

2003

2004

$/kA.m

0

200

400

600

800

1000

1200

Price/Performance Ratio, $/kA
-
m

World’s First HTS Wire
Manufacturing Plant
Opened By AMSC

Price/Performance $/kA.m

200 $/kA.m

B2223 & Commercial Products



At $50/kAm (77K) price/performance ratio
significant markets would be enabled (it was
thought in ~1999):


Utility Generators (>100MVA)


Ship Propulsion Motors and Generators (>5MW)


Wind Turbine Generators (>4MW)


Urban T&D Power Cables


Industrial Magnetic Processing



Significant worldwide industry in B2223


American Superconductor, Innova, Nordic Superconductor,
Sumitomo Electric, Vacuumschmelze, Trithor

Bought and shut down


by AMSC in 2002

Magnetic Field


High magnetic field reduces current
carrying capacity


Lower temperatures enhance current
carrying capacity


Transformers, cables and FCLs are low
magnetic field devices


B2223 at 27K carries twice the current, so
$/kA.m reduces to 100 $/kA.m.

Diboride & YBCO


YBCO and similar compounds have had
research worth $$billions devoted to their
physics and processing.


MgB
2

was discovered in January 2001;
physics now entirely understood.


Both can be made in:


Tape geometry


Massive lumps for
new motor designs

Mg

Mg

Mg

Mg

B

B

B

Magnesium Diboride

s

p

39K

Magnesium Diboride

~ 400 $/kg

Making Diboride tape

Cu
-
sheathed tape

transverse cross
section

Tube filling with

MgB
2

powder

Wire drawing
and/or rolling

Flat rolling

Long lengths can
be now fabricated

irregular cross section

Simple sintering ~700C

In situ B+Mg with Fe barrier in Monel Sheath

With iron

tough to make multifilament
-

most likely be cabled ,

(twisted) monofilaments for low AC loss conductor, working on

Outer sheaths of Monel, Cu/Ni, and Cu to improve stabilization.

Hyper Tech Research


Magnesium Diboride (MgB
2
)


Advantages


No weak
-
link effects, low anisotropy


Easy to fabricate wires, films: <$10/kA.m potential



Challenges


T
c

< 40 K (77 K applications like cables, transformers not
viable)


High field applications such as NMR not viable



Possible applications in 20
-
30K range for modest
field environments, e. g., rotating machinery




YBCO Coated Conductor


Rolled, textured Nickel tape (Ni
-
W)


Oxide buffer layer, preserves texture


YBCO (or analogue, e.g. HoBCO), preserves texture


Near “single crystal” 100s of metres long


<$10/kA.m potential, but extraordinary plant cost




YBCO







Ni tape

Oxide buffer

layer deposition

YBCO







YBCO

precursor







YBCO

oxygenation

and conversion














YBCO Coated Conductor tape


Active programs in US, Japan and Europe



Examples of results in 2001:


122 A (75 K) over 1 m by LANL


World record for meter length


50 A over 10 m by Fujikura


World record for 10 meter length


Over 60 m :Fujikura


World’s longest processed tape

YBCO CC Technical Issues


Adequate uniformity over length



Stability to over
-
currents or cracks



Adequate current in MOD films



Mechanical properties


spalling, cracking



Stability of metal
-
oxide epitaxial interface



Deposition rate for ion beam and laser processes



Thicker than 3 micron YBCO ?



…but must have that 10 $/kA.m process!



B2223 (1G) to YBCO (2G)







Reduced Manufacturing Costs ($/m)
and

Increased Wire
Performance (current carrying capacity)

1995

1996

1997

1998

1999

2000

2001

2002

2003

2004

$/kA.m

0

200

400

600

800

1000

1200

Price/Performance Ratio, $/kA
-
m

World’s First HTS Wire
Manufacturing Plant
Opened By AMSC

Price/Performance $/kA.m

200 $/kA.m

ORNL Model

Assumed by analogy with other fibres

B2223/YBCO Wire cost ($/kA.m)

Magnesium Diboride

Effort

Performance

Technology ‘S’ Curves

Effort

Performance

Copper
-
Iron

HTS g1

MgB
2

75y

17y

2003

HTS g2

Power Technologies

Conclusions:

Superconductors for AC Power


HTS G1:


B2223 tape



Diboride:


MgB
2
wire


HTS G2:


YBCO CC tape



AC Power Superconductors

Refigeration Energy Consumption
Carnot Thermodynamics
0
20
40
60
80
Temp (K)
Energy Consumption
Higher running costs,

lower wire costs

Lower running costs,

uses more wire

Higher running costs =

Higher cryogenic capital costs


Higher magnetic field

capability

Temperatures

0

20

40

60

80

T (K)

He

H

Ne

O

N

CO

Liquid Phase at 1 atmosphere

Cryogen Gap

Cryogenic Cooling Costs

Ideal Energy Consumption

0.00

20.00

40.00

60.00

80.00

0

20

40

60

80

Temp (K)

EC

Carnot

Sterling

27K

77K

10.1x

70.4x

4K

2.9x

14x

9x

30

Cryogenics


High AC power is intrinsic to transformers


Cables have high losses: so need cryogens


Conduction
-
cooled designs need exploring
20
-
24K and 27K
-
60K for other applications


Thermal reservoirs need investigating to
peak
-
shave cryogenics capital costs


Reducing the capital cost of cryogenics is as
important as their efficiency for grid markets

Cooling & Purchase Costs


There is a trade
-
off between cryogenic capital cost
and materials capital cost


colder running means
less material required but more cryogenics.


The cheaper the superconductor, the higher the
optimum operating temperature.


Comparing different materials therefore requires a
whole
-
system comparison


Competition between materials is application
dependent


Transport applications are always more attractive

Cost “Prediction”

Source: Mulholland et al, DOE June 2003

Cryogenic Patents

Cryogenic Cooling System patents filed in the U.S.
0
2
4
6
8
10
12
14
16
18
20
1974
1976
1978
1980
1982
1984
1986
1988
1990
1992
1994
1996
1998
2000
2002
Year
Number of Patents Filed
Cryogenic Cooling System Patents
Cryocooler
Qi3 Limited (2003)

Targets


Copper:
6


22 $/kA.m

(400 to 100

A/cm
2
)


B2223:
100 $/kA.m

(at 27K)


Device

kA/cm
2

Tesla

$/kA.m

Static
Transformer

10
5

1.4

15

Cables

10
5

<0.1

10 ?

Dick Blaugher, NREL

ABB HTS Transformer


100 MVA, 225 / 20 kV



oil free, liquid nitrogen 68K



20% lower weight



80% lower load losses



5% smaller volume



Short circuit reactance 50% of
conventional



25% over
-
loadability without
accelerated ageing



150% first cost



90% lifecycle cost



Short circuit current limitation in first
half wave, self restoring FCL

11 m


135 000
kg

5
m

Other HTS Transformer Benefits


Reduced need for load tap changer
units


Reduced system VAR requirements


Reduction in capacitor banks


With a generator, reduced VAR enables
additional generator capacity so
reduced capital cost of generator

ABB Conclusions


With current costs for energy and equipment, an open loop
refrigeration system is the most economical.


The mechanical refrigeration industry is not currently able to meet
performance targets required for a commercial Utility product.


Cryocoolers are too expensive, maintenance intervals are too
short, and production methods are not cost effective.


The number of competitors in the field is limited, and the
companies are generally small operations.


Production scale
-
up and comprehensive global service could
be problematic


Near term market too small to justify continuation
of project!


Waukesha/ORNL Project


Waukesha 24.9kV to
4.2kV


$10m project


2x overload capability


FCL capability


1 MVA pilot at 25K with
cryocooler


Transformers

Lifetime

Cost of Ownership in $/kW

2000 ABB SPI Phase I Analysis

Cu (330 K)

@ 300 A/cm
2

HTS (68 K)


200$/kAm

MgB
2
(25 K)


Losses

60

Cryo

-

Wire

5

Total

65

5

25

50

80

5

10

34

5

50

Adapted from Paul Grant EPRI

ORNL HTS Transformer


High utilization and
high cryocooler
efficiency required
to get energy
savings (RAND)


Feasible with 10
-
year payback if
<15$/kA.m at 77K.
(Lawrence Assc.)


Energy Efficient Transformers


High
-
copper section designs


Domain
-
refined steels


Ultra
-
thin iron laminations


High
-
field (1.7T) iron alloy core


Metallic glass or amorphous iron core


Lowest first
-
cost purchasing prevents
adoption of any of these technologies.

www.efficient
-
transformers.org

Primary Benefit


The primary benefit in a
superconducting transformer is the
Fault Current Limiting capability
.


Therefore, make FCLs first!

Thankyou

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