DCSwitchcomponents.docx

DCSwitchcomponents.docx

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DCSwitchcomponents

DRAFT

NEPTUNECircuitBreakerComponents

DeniseDennis,CircuitBreakerGroup

April,2002

ABSTRACT

TheNEPTUNEcircuitbreakerisdesignedfor10kVand10Adcsystem.Thecomponentsofthecircuitbreakerincludea2-10Fcapacitor,21kresistorsand3-4vacuumswitches.Thetaskathandistolocatecomponentsthatmeetthedesiredspecifications.Atleasttwosourcesarelocatedforeachcomponent,andcomparisonsofthedifferentproductsarepresented.Insomeinstancestentativepricesareobtained.Atthispointrecommendationsarenotmade,ascertainaspectsofthedesignarenotyetfinalized.

Beyondthecomponentsofthecircuitbreaker,diodesandsurgearrestersareneededineachnode.Theseimportantcomponentsarealsoaddressedinthisreport.

INTRODUCTION

TheNEPTUNEpowersystemisuniqueinseveralrespects.First,thesourcevoltageis10kVdirectcurrent,whichisuncommoninutilitysystems.Second,theoperatingcurrentislargerthanmostindustrialhighvoltagedcapplications.Thiscombinationcreatesachallengeinfindingoff-the-shelvecomponents.

Thecircuitbreakerisdesignedtobeimmersedinstandardtransformeroiltoreducethesizeofthevariouscomponentsandtoprovideaheatexchangemedium.Thecomponentsmustbecapableofwithstandingthegeneratedheatforthelifespanoftheproject.Afigureofthecircuitbreakerisshownbelow,withallswitchesopen.

Figure1.CircuitBreaker

Theworkdonehereiscomposedofthreesteps:

1.Tofindifthecomponentswiththedesiredratingsexist.

2.Ifavailable,thesizeanddurabilityofthecomponentsareexamined

3.Ifallsatisfactory,thecostisconsidered

Circuitbreakercomponents

CAPACITOR

Theinitialinvestigationindicatesthatthebypasscapacitormayhaveavaluedbetween2Fand10F.Thephysicalsizeofacapacitorisdeterminedlargelybyitsvoltageratingaswellasitscapacitance.Sincethevoltageisfixed（10kV）,andthecurrentisdeterminedbythepowerflow,thecapacitanceisthedeterminingfactorforthephysicalsize.10Fcapacitorsareratherlarge,（upto14incheslongestdimension）,the1Fand5Fcapacitorsareconsiderablysmaller（about6incheslongestdimension）.WearecurrentlyusingATPsimulationstoselectthesmallestcapacitancethatlimitsthesystemtransientstoatolerablelevelwhilepreventingrestrikeswhenthebreakerisopening.Asmallercapacitorcouldsignificantlydecreasetheoverallsizeofthecircuitbreakerasdemonstratedbelow,buttheexactsizeistobedeterminedaftertheATPsimulationsarecompleted.

Threesourcesforcapacitorsarelocated,HiVoltCorporation,PlasticCapacitorsIncandHighEnergyCorporation.Thesethreecompaniesmanufacturesimilarproducts.Belowisasummaryoftheircapacitors’specificationsanddimensions.Figures1-3showthegeneraldimensions,andTables1-4givesthespecifications.Table5showsacomparisonbetweentheseproducts.Informationaboutthecompaniesisincludedintheappendix,alongwithdatasheets.

HiVoltCapacitors

Construction:

Dielectricmaterial:

polyester/polypropylenefilmandcapacitortissue;

Case:

hermeticallysealedtinplate,rolled-seamed;

Internalconstructiondesignedtopreventmovementwhencapissubjectedtomechanicalshockorvibration;Externalconnectionsviaceramicterminals;Enamelfinish

Impregnant:

mineraloil

Tolerance:

10%

Temperature:

-55to85C

Applications:

DCapplicationssuchasfilters,bypass,couplingoflowfrequnecyaudio.AlsoPulse-Formingnetworks,energystorage,Highvoltagesmoothing,oscillatorcircuits,arcandsparksuppression

Notes:

Vtest:

2Vratedfor1minute

Figure1.Hi-VoltCapacitorDiagram

10kVDCworkingvoltage

CapacitanceinF

A

B

C

D

E

PMR100-503

0.05

58

80

48

40

60

PMR100-504

0.5

140

80

48

40

60

PMR100-105

1

160

85

67

40

60

PMR100-205

2

140

130

100

50

60

PMR100-605

6

350

130

100

50

60

PMR100-156

15

350

180

180

75

60

Dimensionsareinmm

Table1.HiVoltCapacitors:

ModelsandDimensions

PlasticCapacitors

Construction:

SimilartoMIL-C-19978;notQPLlisted;militarycan,hermetically

sealed;Highvoltageterminalsofthesolder-sealvariety—eliminatesgasketfailure,commonfaultinsomecaptypesasgasketsage;internalindividualcapacitorelementsarewoundusingextendedfoildesign;elementsconnectedtobrassterminalstudwithheavycopperbraid.

Impregnant:

mineraloil,145Cflashpoint

Temperature:

-55to85C

Tolerance:

10%

Applications:

energystorage/dischargeofhighcurrentatlowrepetitionrates

Pulsex-ray,photoflash,laserpumping,pulse-formingnetworks,

Highintensitystrobe

Notes:

Capableofhandlingadead-shortdischarge,thoughnotrecommended.

Figure2:

PlasticCapacitorsDiagram

10KVDC

CapacitanceinF

A

B

C

D

E

LK100-104ND

0.1

3.75

1.75

3.75

2

2.125

LK100-504ND

0.5

3.75

1.75

6.25

2

2.125

LK100-504ZND

0.5

3.75

3.1875

4.25

2

2.125

LK100-105ND

1

3.75

2.25

8

2

2.125

LK100-105YND

1

3.75

3.1875

6

2

2.125

LK100-105ZND

1

4.5625

3.75

5

2

2.125

LK100-205ND

2

4.5625

3.75

7.5

2

2.125

LK100-405ND

4

8

4

9.25

4.5

2.125

LK100-405YND

4

4.5625

3.75

11.5

2

2.125

LK100-605YND

6

7.375

5.625

9

3

2.125

LK100-805YND

8

7.375

5.625

9.75

3

2.125

LK100-106ND

10

13.5

4.125

11

6.75

2.125

LK100-106YND

10

7.375

5.625

12.125

3

2.125

LK100-206ND

20

13.5

6.125

12

6.75

2.125

Dimensionsareininches

Table2.PlasticCapacitors:

ModelsandDimensions

HighEnergyCorporation

Construction:

paper/polypropylenedielectric,platedsteelcasewithoptionalepoxyfinish,ormildsteelwithepoxyfinish.

Impregnant:

‘environmentallycompatibleimpregnant’

Temperature:

-40to85C

Tolerance:

10%

Applications:

PrimarilyusedasfiltersinoutputofhighDCpowersupplies.Canbeusedinbroadcastandradarpowersupplies,andotherhighvoltageDCsupplies.

Figure3.HighEnergyCapacitorDiagrams

DrawnRectangulars

WeldedCase

A

1

1.75

W1

4

8

B

1.19

2.5

W2

4.13

13.5

C

1.25

3.75

W3

5.13

13.5

D

1.75

3.75

W4

6.25

13.5

E

2.25

3.75

W5

7

14

F

2.5

3.75

G

3.19

3.75

K

2.84

4.56

J

3.75

4.56

Sizesareininches

Table3.HighEnergyCorpCapacitorDimensions

C-FVDCbasefigurehtBT

CC692

1

10,000

G

2

5.50

2.00

2.00

CC693

2

10,000

J

2

7.00

2.00

2.00

LC322

5

10,000

W1

3

10.00

3.00

5.00

LC330

10

10,000

W2

3

10.00

3.00

5.00

Dimensionsareinmm

Table4.HighEnergyCorp:

CapacitorsandDimensions

PlasticCapacitors

HiVoltCorp

HighEnergyCorp

Construction

Militarycan,hermeticallysealed;highvoltageterminalsofsolder-sealvariety—eliminatesgasketfailure;internalindividualcapacitorelementswoundusingextendedfoildesign;elementsconnectedtobrassterminalstudwithcopperbraid.

Dielectricmaterial:

polyester/polypropylenefilmandcapacitortissue;hermeticallysealedtinplatecase,rolled-seamed;

Internalconstructiondesignedtopreventmovementwhencapissubjectedtomechanicalshockorvibration;

Externalconnectionsviaceramicterminals

Enamelfinish

paper/polypropylenedielectric,platedsteelcasewithoptionalepoxyfinish,ormildsteelwithepoxyfinish.

Impregnant

mineraloil,145Cflashpoint

mineraloil

environmentallycompatibleimpregnant

Temperature

-55to85C

-55to85C

-40to85C

Tolerances

10%

10%

10%

Applications

Energystorage/dischargeofhighcurrentatlowrepetitionrates

Pulsex-ray,photoflash,laserpumping,pulse-formingnetworks,

Highintensitystrobe

DCapplicationssuchasfilters,bypass,couplingoflowfrequencyaudio.AlsoPulse-Formingnetworks,energystorage,highvoltagesmoothing,oscillatorcircuits,arcandsparksuppression

PrimarilyusedasfiltersinoutputofhighDCpowersupplies.Canbeusedinbroadcastandradarpowersupplies,andotherhighvoltageDCsupplies.

Notes

Capableofhandlingadead-shortdischarge

2Vratedfor1minute

Table5.CapacitorComparison

Figure4.Volumevs.Capacitance.Thelinearrelationshipbetweenvolumeandcapacitanceisapparent.Thecircuitbreakercouldbesignificantlysmallerifalowercapacitanceisused.

ThechartinFigure4showsthecapacitorvolumevs.itscapacitance.Therelationshipdemonstratesthatthesizeislinearlyreducedwhenthecapacitanceisreduced.

Thecostofthecapacitorsrangesfromaround$150forthe1Ftocloseto$500forthe10Fversion.

RESistors

Tworesistorsarerequiredforthecircuitbreaker（seeFigure1.R1andR2）.Oneisforthesoft-closingofthecircuitbreaker.Thesecondisforthedissipationofthestoredenergyofthecapacitorafterthebreakerisopened.Thetaskhereistofindresistorswhichcanwithstandthepowerandenergyforeachoftheseoperations.Threesourceswerelocated,KanthalGlobar,TeproElectrotechnik,andNicromElectronic.Companyinformationanddatasheetsarelocatedintheappendix.

Softcloseresistor

Intheinitialdesignofthebreaker,theR1=1kresistorisselectedforthesoftstartingprocess.Duringtheclosingsequenceofthebreaker,theresistanceispresentinthecircuitfort=1second.Inrealitythistimewillprobablybeshorter,butt=1secondisusedforpowerandenergycalculations.Thepower（P）andenergy（E）requirementsoftheresistorarecalculatedasfollows:

Thecurrentofthebreakerisassumedtobe1A.Thisisbecauseweareassumingthatwhenthebreakerisclosing,itexcitesonlyonesectionwithonenode.

NicromElectronicmanufacturesaresistorappropriateforourpurposes.Thisisthe500.100