6 AP HTS Transformer Technology

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HTS Transformerv

c wen er y

Oak Ridge National Laboratory

Ed PlevaWaukesha Electric Systems

June 30, 2010

Team:

- c wen er y, ona an em o, v n s,Robert Duckworth, Randy James, Isidor Sauers, EnisTuncer

WES- Ed Pleva, Sam Mehta, Vinay Mehrotra, Bob

1 Managed by UT-Battellefor the Department of Energy

Del Vecchio


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Project Purpose

To establish the technical and economic benefits ofHTS Transformers of >10-MVA ratings.

To carry out materials studies in support of thisdevelo ment.

Supports DOE-OE Mission and Subprogram goals:Modernize electric grid; Smart Grid Program.

Enhance security, reliability and efficiency of energyinfrastructure.

Develop revolutionary power equipment using HTS wires.

Characterize dielectric materials and establish design rules.


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.


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Program Historyase : , , an

1 MVA 1- prototype tested 199813.8kV HV/6.9kV LV; Bi-2212; 25 K

HV, vacuum, ac loss testing, cold mass assy at ORNL

rea own cause y ;

later reached 13.8 kV in airPhase 2: 2000 2005 (WES, SuperPower, ORNL and Energy East)

5/10 MVA 3- prototype tested 2003-4. . -

HV, ac loss testing, cooling system design/fab at ORNL

Transformer failed HV dielectric tests; cracked epoxy

insulation; root cause & lessons learned analysis done

ase : resen ,

WES using internal funds; DOEbase program funding to ORNL

Conceptual design rework; 70-K YBCO;

cryogen c e ec r c ac oss es ng,composite dewar development at ORNL

Simplify manufacturing process

Phase 4: Future (WES, SP, SCE, ORNL)


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Construct 28-MVA FCL Smart Grid Demo Transformer for SCE


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Why HTS Transformers? HTS transformer develo ment is underwa worldwide.

Projects in Japan, Korea, China, India, Australia.

Many transformers in the grid are aging, creating a ready HTS market.

2 .

Conventional transformer losses are 40% of total grid loss because they are sonumerous

If HTS transformer is 0.2% more efficient, losses are reduced by 1/3

~ 107 ton annual CO2 reduction

Transformer size, weight, fire hazard, and environmental impact reduced.

Overload o eration is ossible with no loss of lifetime.

Fault current limiting (FCL) capability is possible supports Smart Grid.THIS IS UNDER DEVELOPMENT IN A NEW COLLABORATION WITH SUPERPOWER

AND SOUTHERN CALIFORNIA EDISON.

FCL transformer development helps other FCL projects

High-voltage insulation, dewar development

Conductor cooling, YBCO properties


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Fault Limiting Equipment is

Enabler of Smart GridWithout limiter

Fault currents are growing

inexorably in expanding urban grids

With HTS limiter

Need fast limiting of fault currents avoid damage to grid and equipment

avoid power interruptions

Smart Grid vision of re-configurable networks

re uires connectivit

Fault currentlimitinge ui ment


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OUTLINE Research plan

Summary of new 28-MVA FCL Smart GridTransformer project

Specifications Ed Pleva

Overall configuration

Windin details

Composite dewar long-term testing

AC Loss testing and calculation

550-kV BIL flashover test coil Bill Schwenterly

Bushing tests

Technology Transfer/Collaborations

Future Plans


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Overall Research Planon nuous y evo ve concep ua es gns or rans ormers us ng

YBCO immersed in pressurized, subcooled nitrogen.

Near-term, develop FCL HTS analog for conventional unit.

- .

Far-term, with low-cost conductor and refrigeration, develop HTSunit that exceeds conventional performance at same cost insmaller envelope.

Carry out high-voltage tests to qualify electrical insulationsystems up to 115-138 kV operating voltage and 650 kV BIL.

Perform ac loss, stabilit , and fault handlin tests on sub-scaletest coils.

Support development of suitable dewar vessels.

Perform other materials tests as needed.

NEW PHASE In FY2010, WES/ORNL team joined withSuperPower and Southern Calif. Edison in a successfulproposal to develop a 28-MVA superconducting FCL


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transformer for SCEs Smart Grid site in Irvine, California.


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FY 2010 activity has centered on securing new

, ,losses, and high-voltage insulation.

Funding Action DOE Smart Grid RegionalDemonstration funding has been approved for 28-MVA

.

Milestone Open-top composite dewar successfully

passed four-month long-term test.

Milestone Further ac loss tests on YBCO simulatedHV coils were carried out.

550-kV BIL.

Long-term testing will begin on epoxy resin bushing.


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DOE Smart Grid Regional

for a 28-MVA HTS FCL transformer.

Rating: 28-MVA; 70.5 kV / 12.47 kV; 132 A / 1296 A

13.1% impedance to match existing conventional units.

Increase to 26% im edance in HTS uench ives 50% reductionof fault current.

Continuous operation at 40.6 MVA (145% of rated load) withextra liquid nitrogen supply.

Normal operation at 70 K, 3.4 bar.

HTS is sized for sufficient margin on 40.6-MVA current.

.

Current leads are sized for 125% of 28-MVA current.

Maximum current lead temperature rises to


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Conceptual Design

manufacturing techniques wil lutil ize experienced WES coilwinders.

Uses WES design software &

ORNL design spreadsheet.

70-K pressurized, subcooled

for oil.

HTS tape with parallel resistive

conductor for stability andau an ng.

Coil dewar surrounds warmsteel core.

- .

Proof of concept with single-phase Alpha-1 (normalconductor) and Alpha-2 (HTS)


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un s.


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2G-HTS Conductor Architecture Under

Original design used parallel copper.Motivated b ANSI re uirement for a conventional non-FCL

transformer to recover normal operation after a 2-sec fault.

This had disadvantages:Re uired amount of co er is nearl as much as in a

conventional unit.

Copper produces high eddy current losses.

Evaluatin allo o tions for re lacin co er.High resistance after HTS quenches reduces fault current to

about half that of conventional unit.

Eddy current losses are reduced.

SCE substation has type CO-8 distribution breakers.Opening t ime is ~1 sec in area of interest for 28 MVA.


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.

Few-minute re-cool time.


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The windings will be similar to WESs

. HV Continuous disc winding;

single conductor, 8-12 turns/disc.

crew w n ng; - con uc ors n

parallel. Transposed to give uniformcurrent sharing.

individually-tested modules to limitamount of conductor at risk in a testfailure.

Standard 6 or 12 mm 2G HTS tape withhigh resistance alloy strip.

Provides robust conductor that can be

insulated on high-speed machine.

High-resistance

alloy


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InsulationHTS


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28-MVA unit will be proof-tested at SCE

- , .


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Technical Progress

S. W. Schwenterly, ORNL


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The open-top composite dewar

- . Dewar performed well in vacuum and thermal cycling tests in

FY2009. Paper at 2009 Cryo.Eng. Conference.

-

maintain10-3 torr warm,


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Test coils help predict ac loss.- - .

HTS tape is bare, insulation is only around co-wound conductor to preventbuckling. 4-mm disc spacers machined from clear plastic.

Simulated high voltage winding 26 six-turn discs, continuously wound by, . -mm ape, . cm , . cm eng , m o ape, -

measured Ic (equivalent to 50 A rms).

Electronic loss measurement with lockin amplifier external toroidal air-core bucking transformer to cancel inductive signal has been added.

Validation third coil with only copper showed the expected resistive losses, atboth RT and 77 K.

New cryostat in the composite dewar with pumped LN bath allows testingat reduced tem erature, with no effect b nearl metal wall.


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Coil with co-wound copper was tested at reduced temperature and

several frequencies in this dewar.


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Losses in HV prototype coils exhibit non-linearcurrent dependence

Losses (Ipeak/Ic)n. Losses are similar for

co-woun u an

Stainless. ForIpeak/Ic < 0.4, n ~

. .

Consistent with

ferromagnetic Ni-W

ForIpeak/Ic > 0.4, n ~ 2.

Eddy or coupling

mec an sm


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Losses in HTS/Cu coil varied as square of

fre uenc and were tem erature inde endent. Dividing ac loss by square

of frequency collapses the.

Loss proportional to squareof the frequency alsosuggests coupling or eddymec an sm.

Very l itt le change in losswhen temperature is lowered

rom o sugges smost of loss from Cu or HTSsubstrate.

HTS/SS coil will et similar


18Presentation_name

tests.


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Losses are higher at the coil ends

Each VT pair covers 2 discs.


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a a e s a en s ncrease osses.


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Insulation studies for 550 kV BIL

. Similar 350-kV BIL coi l

passed all tests in FY2008Flashover

New WES Test Coil

Standard WES designpressboard structure

Copper conductor withWES polymerinsulation

LVHV

LV & HV disc windings

HV Tests in LN in Fall2009

Bushin Test

Commercial 650 kVBIL bushingsuccessfully testedshor t-term in FY09

Long-term testplanned for smaller28-kV model


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Test Results - 550-kV Coil

HV coil was impulsed from topwith bottom & LV coil grounded.

-

1.8 bar absolute to stop boiling.Passed 3 impulse shots at -550 kV

.

Warmed up and un-grounded the

HV coil.Test with ac voltage showed 2.2 pC

partial discharge at 102 kVac.

Passed 1-min withstand at 201

kVac.650-kV impulse tests planned if

fundin available.


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FY 2010 Plans FY 2010 Performance Seek new funding options DOE Smart Grid Regional

Demonstration funding has been

MilestoneYBCO ac loss andIc testing

approved for 28-MVA FCL unit.

Carried out further Ic and ac loss testson YBCO sample coils with co-wound

Carry out further dielectrictesting

.

New 115 KV/550 kV BIL coil passed550kV impulse / 200 kV withstand;

long-term bushing tests started.es one ompos e ewar

testing and procurement

Modify WES transformer

Long-term tests on small open-topdewar completed successfully; newprocurement under consideration.

WES ro rams are now in use for HTS

design programs for HTS Begin 5/7-MVA single-phase

prototype substation

unit designs. Replaced by new 28-MVA FCL unit

project.


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Technology Transfer, Collaborations

New collaboration with SuperPower and SCE on a Smart Gridproposal for fault current limiting transformers has receivedDOE funding approval.

Team possesses strong complementary abili ties in research,engineering, manufacturing, & utility operation.

. ,2X WES to ORNL, Smart Grid FCL transformer team meetingsat WES and SP. Communication several t imes a week by phoneand E-mail.

Team is working with suppliers to develop dewars and qualifybushings. A 650-kV commercial bushing was used for impulse

Paper on composite dewar was presented at 2009 CEC/ICMC.


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Applied Superconductivity Conference.


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FY 2011 Plans

Su ort 28-MVA FCL unit conce tual desi n and en ineerinanalysis.

Cryogenic, electrical, mechanical issues

Support detail design of single-phase Alpha-1 unit with

Qualify YBCO materials for the reference design.Support SuperPower and WES in specification and

roduction of HTS FCL conductor laminated to a resist ivemetallic strip

Test sample coils with SP conductor wound by WES in

subcooled liquid nitrogen: -multiple-tape coils

Critical current and stability under operating conditions

Fault current handling, recovery, and load restoration after

Address Technology Issues.

Continue long-term bushing tests in LN.


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of single-phase test dewar for proof of concept.


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WES and ORNL continue to be committed

to the development of HTS transformers.

We welcome the

artici ation of

SuperPower

and SCE!

QUESTIONS?


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6 AP HTS Transformer Technology

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