04 0800 hvdc plenary rashwan

7/30/2019 04 0800 Hvdc Plenary Rashwan

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IEEE 2011 Electrical Power and Energy Conference

State of the VSC technology

October 2011Presented by

Dr. Mohamed RashwanTransGrid Solutions


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LCCdevelopment

Firstthyristorvalvesystemin1972EelRiver.Aircooledthyristorvalves320MWBacktoBack.Togetthecurrentrangof2000A,4thyristorsare

connectedinparallel.

In1978firstwatercooledthyristorsysteminNelsonRiverratedat2000MW.Togetthecurrentrangof2000Atwothyristorswereconnectedinparallel.

In2004ThreeGorgesat3000MW.Noparallelconneconofthyristors.Theintroduconof5inchthyristorsof8kVand3500A(32yearsaSer

thefirstthyristorscheme)

In2009Introduconof6inchthyristorsanddcpowerupto6000MWperbipoleat+/-800kV(37yearsaSerthefirstthyristorscheme)

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VCdevelopment

1997Hellsjnexperimentalprojectat3MW 2002CrossoundCableat330MWand+/-150kV(5yearsaSerHellsjn)

2010TransBayat400MWand+/-200kV.Thisintroducedthefirstmul-levelconverter(13yearsaSerHellsjn)

2012VCupto500kVand700MWconverter(14yearsaSerHellsjn)

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Reactive Power requirements Does not consume any reactivepower and each terminal can

independently control its

reactive power.

Filtering Requires moderate size filter banks or no filters at all.

Black start Capable of black start and

feeding passive loads

AC system short circuit level Not critical at all

Commutation failureperformance

Does not fail commutation

Over load capability Does not have any overloadcapability

Application with overheadlines

Can be applied but dc linefaults are critical

Small taps Economic and seems not affectthe performance

Load rejection over voltage not large because of small sizeof filters if required.

Foot print Small for the comparable rating toan LCC

Off shore wind farms Straight forward application

Power losses Approximately 0.9% per terminal


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VSCHVDCtransmissionConfigura2on Inymmetricalmono-polarconfiguraonwheretheconvertersareconnectedbetweentwohighvoltageconductorsofoppositepolarity.The

groundreferencecanbeprovidedthroughhighimpedance.

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Positive conductor

Negative conductor

VSC based HVDC link with symmetrical mono-polar configuration


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VSCHVDCtransmissionConfigura2on Thistypeofconfiguraonhasbeenusedforthetwoorthreelevelconverter

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Symmetrical mono-polar configuration with dc capacitor mid

point grounding


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VSCHVDCtransmissionConfigura2on

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Positive

dc Voltage

Idc

Negative

dc

Voltage Idc

VSC bipolar arrangement


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IGBTs

IGBTsfortheVCapplicaonscanbepress-packorwirebonded

Press-packIGBTnosolderorwirebondjointssimilarinphysicalshapeasthyristorsandFailssafeshortcircuit

Wirebonded:mayexplodeonfailure

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Mul2-chipdesignofIGBT(fromABB)

takPakIGBThastwo,three,fourorsixsub-modules.Thenumberofsub-

modulesisselectedbasedonthecurrentrangoftheapplicaon

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The largest type of a reverse

conducting press pack comprising 48 IGBT and 24 diode

chips

has a rating of 4500V and 2000A


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IGBT3300V1200AMitsubishi

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Ud/2

Id

Ud/2

Uac

t

Uac

Ud/2

-Ud/2

Iac

VSC basic principles


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Ud/2

Id

Ud/2

Uac

t

Uac

Ud/2

-Ud/2

Iac


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Ud/2

Id

Ud/2

Uac

t

Uac

Ud/2

-Ud/2

Iac

Uac can be set to Ud/2 or Ud/2 independent of Iac, hence the name Voltage Source


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14

Uac1

Uac2

Uacn

Ud1

Ud2

Udn

Uac1

t

Ud1

Uac2

t

Ud2

Uacn3

t

Ud3

Uac

t

Uac

Multi level converter


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VSC ~

UcnvUsys

Icnv

X

Usys

UcnvUsys-UcnvIcnv=(Usys-Ucnv)/jX

Case 1: Coverter absorbing reactive power

Usys

Ucnv

Usys-Ucnv

Icnv

Case 2: Converter producing reactive power

Icnv

Reactive Power


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Usys

Ucnv

Usys-Ucnv

Icnv

Converter absorbing active power

Usys

Ucnv

Usys-UcnvIcnv

Converter producing active power

Active power is primarily determined by

angle Delta

Active Power


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P

Q

Max Q, nominal

AC voltage

Max MVA- mainlytransformer MVA limit

Max Q, MaxAC voltage

P-Q diagram


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Cigre paper 2010 B4-203

Performance


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Cigre paper 2010 B4-203

IGBT performance


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Conclusions

TheVCtechnologyisdevelopingfastandtheconverterrangsareincreasing.Inmyopinionwewillseerangsintherangeof2000MW

comingintothemarketinfewyears

TheVCmul-levelconverterisbecomingthebaseforthetechnology Thedevelopmentsofthedcgridswillcreatealotofopportunityforresearchanddevelopment.Thisisrealbecauseitisbeingpropelledbythe

integraonofrenewablesandthewillofgovernmentsmostlyinthe

Europeancommunity

Finallyweneedtosolvetheissueoftheoverheadlinedcfault.Whether,afastdcbreaker,circuittopology,oranyothermeans

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Thank You

04 0800 hvdc plenary rashwan

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