hvdc transmission ppt part 1

7/26/2019 Hvdc Transmission Ppt Part 1

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HVDC TRANSMISSION

Part 1


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Text Books:

Direct current Transmission b !D"ARD "I#SON

$IMBAR$%"i&e interscience' Ne( ork'1)*1+,

Hi-. Vo&ta-e D,C,Po(er Transmission sstem b

$,R,PADI/AR IISc Ban-a&ore' Ne( A-e Internationa&Pub&is.ers #t0,


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Oerie(:

2enera& As3ects o4 DC transmission an0 com3arison o4

it (it. AC transmission,

Conerter Circuits

Ana&sis o4 t.e Bri0-e conerterContro& o4 HVDC Conerters an0 Sstems,

Protection,


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PART A %5nit 1 6 7+

2enera& As3ects o4 DC Transmission an0 com3arison o4 it(it. AC Transmission

Historica& Sketc.

Constitution o4 !HV AC an0 DC &inks,

#imitations an0 A0anta-es o4 AC an0 DC transmission,


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Historica& Sketc.:

!o&ution o4 Po(er Sstems:

#ate 18*9s Commercia& use o4 e&ectricit,

In 1887 ;irst !&ectric 3o(er sstem (.ic. inc&u0es 2enerator'

Cab&e'4use'#oa0 0esi-ne0 b T.omas !0ison at Pear& Street station in

Ne( ork,

It (as DC Sstem %#o( Vo&ta-e 119V+'un0er-roun0 cab&e is use0 to

0istribute t.e 3o(er to consumers, On& #imitation o4 DC

Hi-. &osses an0 Vo&ta-e Dro3

Trans4ormation o4 Vo&ta-e re?uire0,


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Continues@

Trans4ormer an0 AC 0istribution %1


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Continues

In 18);irst P.ase &ine '7,$V'17 $m in Ca&i4ornia ,

Im3roement in o&ta-es ear b ear'

1)771>


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Continues@

Stan0ar0 o&ta-es are 111'79$V 3re4erre0 4or Hi-.

Vo&ta-e %HV+&ines,

Remainin- =


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!ntr o4 HVDC sstem:

HVDC transmission (as 0esi-ne0 b a ;renc. !n-ineer'R!N! TH5R/, Simu&taneous& AC sstem (as a&so

0ee&o3e0 s&o(&,

In bet(een 18891)11'at&east 11 T.ur sstem (ere insta&&e0

in !uro3e, T.e 3rominent (as Mouteirs to #ons%;rance+ in1)9>, It com3rises 189$m%=,< km un0er-roun0

cab&e+'=,M"'$V'*


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Continues@,

In1)79Transerter%Mec.anica&conerter3o&3.asetrans4ormer+(ere 0ee&o3e0, A-ain AC sstem 0ominate0,

In 1)8A&& t.e T.ur sstem (ere 0ismant&e0, Because in

DC sstem' (e nee0 4re?uent maintenance ' cost a&so is not

e44ectie,A-ain AC reo&ution back ti&& 1)


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#imitations o4 HVAC

Reactie 3o(er &oss

Stabi&it

Current carrin- ca3acit

Skin an0 ;erranti e44ect

Po(er 4&o( contro& is not 3ossib&e,


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A0anta-es o4 HVDC

No reactie 3o(er &oss

No Stabi&it Prob&em

No C.ar-in- Current

No Skin 6 ;erranti !44ect

Po(er contro& is 3ossib&e

Re?uires &ess s3ace com3are0 to ac 4or same o&ta-e

ratin- an0 sie,

2roun0 can be use0 as return con0uctor#ess corona &oss an0 Ra0io inter4erence


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Continues@

C.ea3er 4or &on- 0istance transmission

Asnc.ronous o3eration 3ossib&e

No s(itc.in- transient

No transmission o4 s.ort circuit 3o(er

No com3ensation 3rob&em

#o( s.ort circuit current

;ast 4au&t c&earin- time


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Disa0anta-es o4 HVDC

Cost o4 termina& e?ui3ment is .i-.

Intro0uction o4 .armonics

B&ockin- o4 reactie 3o(er

Point to 3oint transmission

#imite0 oer&oa0 ca3acit

Hu-e reactie 3o(er re?uirement at t.e conerter

termina&s,


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Com3arison o4 AC an0 DC Transmission

T.e re&atie merits o4 t.e t(o mo0es o4 transmission%ACan0 DC+ (.ic. nee0 to consi0ere0 b a sstem 3&anner are

base0 on t.e 4o&&o(in- 4actors:

!conomics o4 Transmission

Tec.nica& 3er4ormance

Re&iabi&it

A maor 4eature o4 3o(er sstems is t.e continuous

ex3ansion necessitate0 b increasin- 3o(er 0eman0 ,

T.is im3&ies t.at t.e estab&is.ment o4 a 3articu&ar &ine

must be consi0er as a 3art o4 an oera&& &on- term sstem

3&annin-,


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!conomics o4 3o(er transmission:

T.e cost o4 transmission &ine inc&u0es t.e inestment an0o3erationa& costs,

Inestment cost inc&u0es'

Ri-.t o4 (a

Transmission to(ers Con0uctors

Insu&ators

Termina& e?ui3ment

O3erationa& costs inc&u0es

It main& 0ue to cost o4 &osses


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Ri-.t o4 "a%Ro"+:

An e&ectric transmission &ine ri-.to4(a %RO"+ is astri3 o4 &an0 use0 b !&ectrica& uti&ities to construct'

o3erate' maintain an0 re3air t.e transmission &ine

4aci&ities,

Ri-.ts o4 (a ma a&so inc&u0e t.e 3urc.ase o4 ri-.ts toremoe 0an-er trees, A 0an-er tree is a tree outsi0e t.e

ri-.t o4 (a but (it. t.e 3otentia& to 0o 0ama-e to

e?ui3ment (it.in t.e ri-.t o4 (a, I4 t.e 0an-er tree

4a&&s or is cut 0o(n' it cou&0 strike 3o&es' to(ers' (ires'&ines' a33&iances or ot.er e?ui3ment an0 0isru3t t.e 4&o(

o4 e&ectricit to our customers,


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Ima-es 4or %Ro"+


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Continues@


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Continues@

T.is Im3&ies t.at 4or a -ien 3o(er &ee&' DC &inesre?uires &ess Ro"' Sim3&er ' an0 c.ea3er to(ers an0

re0uce0 con0uctors an0 insu&ator costs,

T.e 3o(er &osses are a&so re0uce0 (it. DC as t.ere are

on& t(o con0uctors are use0,No skin e44ect (it. DC is a&so bene4icia& in re0ucin-

3o(er &oss mar-ina&&,

T.e 0ie&ectric &osses in case o4 3o(er cab&es is a&so er

&ess 4or DC transmission,T.e corona e44ects ten0s to &ess si-ni4icant on DC

con0uctors t.an 4or AC an0 t.is &ea0s to c.oice o4

economic sie o4 con0uctors (it. DC transmission,


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Continues@

T.e ot.er 4actors t.at in4&uence t.e &ine cost are t.e costo4 com3ensation an0 termina& e?ui3ment,

In 0c &ines 0o not re?uire com3ensation but t.e termina&

e?ui3ment costs are increase0 0ue to t.e 3resence o4

conerters an0 4i&ters,


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Variation o4 cost (it. &ine &en-t.:


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Descri3tion:

AC ten0s to be more economica& t.an DC 4or 0istances&ess t.an Break een 0istance an0 cost&ier 4or &on-er

0istances,

T.e breakeen 0istances can ar 4rom


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Tec.nica& 3er4ormance

T.e DC transmission .as some 3ositie 4eatures (.ic.are &ackin- in AC transmission, T.ese are main& 0ue to

t.e 4ast contro&&abi&it o4 3o(er in DC &ines t.rou-.

conerter contro&,

Advantages:Full control over power transmitted.

The ability to enhance transient and dynamic

stability in associated AC networks.

Fast control to limit fault currents in DC lines.

This makes it feasible to avoid DC breakers in two

terminal DC links.


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Continues@

STA!"!T# "!$!TS:

T.e 3o(er trans4er in AC &ines is 0e3en0ent on t.e an-&e

0i44erence bet(een o&ta-e 3.asors at t.e t(o en0s, ;or a

-ien 3o(er &ee&' t.is an-&e increases (it. 0istance,

T.e maximum 3o(er trans4er is &imite0 b t.e

consi0erations o4 stea0 state an0 transient stabi&it, T.e

3o(er carrin- ca3abi&it o4 an AC &ine as a 4unction o4

0istance,

But in DC &ines (.ic. is una44ecte0 b t.e 0istance o4transmission,


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Po(er trans4er ca3abi&it Vs, Distance


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Continues@

%&"TA'( C&)T*&"

T.e o&ta-e contro& in AC &ines is com3&icate0 b &ine

c.ar-in- an0 in0uctie o&ta-e 0ro3s,

T.e o&ta-e 3ro4i&e in a AC &ine re&atie& 4&at on& 4or

4ixe0 &ee& o4 3o(er trans4er corres3on0in- to sur-eim3e0ance &oa0in- %SI#+ or norma& &oa0in-,

T.e Vo&ta-e 3ro4i&e aries (it. t.e &ine &oa0in-, ;or

constant o&ta-e at t.e &ine termina&' t.e mi0 3oint o&ta-e

is re0uce0 4or &ine &oa0in- .i-.er t.an SI# an0 increase04or &oa0in-s &ess t.an SI#,


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Variation o4 Vo&ta-e a&on- t.e &ine:


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Continues@

"ine compensation:AC &ines re?uire s.unt an0 series com3ensation in &on-

0istance transmission' main& to oercome o4 t.e &ine

c.ar-in- an0 stabi&it &imitations,

Series ca3acitors an0 s.unt in0uctors are use0 4or t.is

3ur3ose,

T.e increase in 3o(er trans4er an0 o&ta-e contro& is

3ossib&e t.rou-. t.e Static Var Sstems %SVS+,

In AC cab&e transmission' it is necessar to 3roi0e s.unt

com3ensation at re-u&ar intera&s,


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A (.o&e 3icture o4 ;ACTS 0eices 4ami&:


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Continues@

+*&"($S &F AC !)T(*C&))(CT!&):".en t(o 3o(er sstems are connecte0 t.rou-. AC

ties%Snc.ronous interconnection+'t.e automatic -eneration

contro& o4 bot. sstems .ae to be coor0inate0 usin- tie &ine

3o(er an0 4re?uenc si-na&s,

!en (it. coor0inate0 contro& o4 interconnecte0 sstems' t.e

o3eration o4 AC ties can be 3rob&ematic 0ue to

a+ T.e 3resence o4 &ar-e 3o(er osci&&ations (.ic. can &ea0 to

4re?uent tri33in-,

b+ Increase in 4au&t &ee&

c+ Transmission o4 0isturbances 4rom one sstem to t.e ot.er


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Continues@

T.e contro&&abi&it o4 3o(er 4&o( in DC &ines e&iminatesa&& t.e aboe 3rob&em, In a00ition' 4or asnc.ronous DC

ties' t.ere is no nee0 o4 coor0inate0 contro&,

It is obious t.at t(o sstems (.ic. .ae 0i44erent

nomina& 4re?uencies cannot be interconnecte0 0irect&(it. AC ties an0 re?uire t.e use o4 DC &inks,


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Continues@

'*&,)D !$+(DA)C(:

In AC transmission' t.e existence o4 -roun0%ero

se?uence+current cannot be 3ermitte0 in stea0state 0ue to

.i-. ma-nitu0es o4 -roun0 im3e0ance (.ic. (i&& not on&

a44ect e44icient 3o(er trans4er' but a&so resu&t in te&e3.oneinter4erence,

But -roun0 im3e0ance ne-&i-ib&e 4or DC currents an0 a DC

&ink can o3erate one con0uctor (it. -roun0

return% Mono3o&ar o3eration+, T.e -roun0 return is

obectionab&e on& (.en burie0 meta&&ic structures %Suc. as

3i3es+ are 3resent an0 are subect to corrosion (it. DC

current 4&o(,


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Re&iabi&it:

T.e re&iabi&it o4 DC transmission is ?uite -oo0 an0com3arab&e to t.at AC sstems,

An ex.austie recor0 o4 existin- HVDC &inks in t.e

(or&0 is aai&ab&e 4rom (.ic. t.e re&iabi&it statistics

cab be com3ute0, It must be remembere0 t.at t.e 3er4ormance o4

T.ristor a&es is muc. more re&iab&e t.an mercur arc

a&es an0 4urt.er 0ee&o3ments in 0eices' contro&'

3rotection is &ike& to im3roe t.e re&iabi&it &ee&,


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Continues@

T.ere are t(o measures o4 oera&& sstem re&iabi&it

a+ !ner- aai&abi&it

b+ Transient re&iabi&it


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!ner- aai&abi&it:

!?uia&ent outa-e time is t.e 3ro0uct o4 t.e

actua& outa-e time an0 t.e 4raction o4 sstem

ca3acit &ost 0ue to outa-e,


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Transient re&iabi&it:

T.is is t.e 4actor s3eci4in- t.e 3er4ormance o4 HVDC sstems

0urin- recor0ab&e 4au&ts on t.e associate0 AC sstems,

Recor0ab&e AC sstem 4au&ts are t.ose 4au&ts (.ic. cause one ormore AC bus 3.ase o&ta-es to 0ro3 be&o( )9E o4 t.e o&ta-e 3rior

to t.e 4au&t,

It is assume0 t.at t.e s.ort circuit &ee& a4ter t.e 4au&t is not be&o(

t.e minimum s3eci4ie0 4or satis4actor conerter o3eration,

oth energy availability and transient reliability of e-isting

DC systems with thyristors valves is /0 or more.


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HVDC outa-e statistics:

T.e aera-e 4ai&ure rate o4 t.ristors in a a&e is &ess t.an 9,>E

3er o3eratin- ear, T.e maintenance o4 t.ristor a&es is a&so

muc. sim3&er t.an t.e ear&ier mercur arc a&es,

hvdc transmission ppt part 1

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