

© A B

B G r o u p - 2 -

S e p

2 8 ,

2 0 1 5

Network General

Line Inductance and capacitance



© A B

B G r o u p - 3 -

S e p

2 8 ,

2 0 1 5

Network General Typical Values

Voltage X1 X0Level ohm/km ohm/km10 0!" 1!#"00 0! 1!$



© A B

B G r o u p - 4 -

S e p

2 8 ,

2 0 1 5

Network General

%ower Line



© A B B G r o u p - 5 -

S e p

2 8 ,

2 0 1 5

Network General

%ropagation speed and &urge impedance



© A B B G r o u p - -

S e p

2 8 ,

2 0 1 5

Network General

%ropagation speed and &urge impedance



© A B B G r o u p - ! -

S e p

2 8 ,

2 0 1 5

Network General

&urge impedance load

Sur"e i#pedance loadin" $ S%&' o( a line i) t*e

po+er deli,ered b- a line to a purel- re)i)ti,e load

e.ual to it) )ur"e i#pedance/

S%& $ &' 3 , ' $ &3' 6

Po+er )-)te# en"ineer) (ind it con,enient to

e7pre)) t*e po+er tran)#itted b- a line in ter#) o(

per unit o( S%&



© A B B G r o u p - 8 -

S e p

2 8 ,

2 0 1 5

Network General


At )ur"e i#pedance load t*e reacti,e po+er

produced in t*e )*unt capacitance o( t*e line

i) )a#e a) t*e reacti,e po+er con)u#ed b-t*e reactance alon" t*e line/



© A B B G r o u p - -

S e p

2 8 ,

2 0 1 5

Network General


Sur"e i#pedance load i) nor#all- con)idered (or

,er- lon" tran)#i))ion line) at ,er- *i"* ,olta"e)/

9or t*e)e ca)e) actual po+er )*ould not de,iatetoo #uc* (ro# )ur"e i#pedance

9or 220 k line $ Sin"le conductor' : 120 6

9or 400 k line $;uple7 conductor' : 500 6



© A B B G r o u p - 1 0 -

S e p

2 8 ,

2 0 1 5

Network General

Trans(erred active power ) &urge impedance load

and no reactive power taken at receiving end

olta"e at recei,in" end < olta"e at )endin" end

olta"e *i"*er at t*e #iddle o( t*e line i( ,olta"e

kept e.ual at bot* end)



© A B B G r o u p - 1 1 -

S e p

2 8 ,

2 0 1 5

Network General

Trans(erred active power * &urge impedance load

and no reactive power taken at receiving end

olta"e at recei,in" end = olta"e at )endin" end

olta"e lo+er at t*e #iddle o( t*e line i( ,olta"e

kept e.ual at bot* end)



© A B B G r o u p - 1 2 -

S e p

2 8 ,

2 0 1 5

Network General

+epresentation o( short lines ) ,0k-



© A B B G r o u p - 1 3 -

S e p

2 8 ,

2 0 1 5

Network General

+epresentation o( long lines ,0 . $00 k-



© A B B G r o u p - 1 4 -

S e p

2 8 ,

2 0 1 5

Network General

ctions to reduce voltage drop

>eep )er,ice ,olta"e *i"*

;ecrea)e reacti,e po+er (lo+ in line b-

producin" reacti,e po+er %n)tall )*unt capacitor)

?educe inducti,e reactance o( line

%n)tall )erie) capacitor



© A B B G r o u p - 1 5 -

S e p

2 8 ,

2 0 1 5

Network General

&ynchronous staility

An"ular c*an"e %( tran)(erred po+er durin" (ault i) @ero

N k G l



© A B B G r o u p - 1 -

S e p

2 8 ,

2 0 1 5

Network General

&ynchronous staility 23ual area method

An"ular c*an"e %( tran)(erred po+er durin" (ault i) not @ero

N k G l



© A

B B G r o u p - 1 ! -

S e p

2 8 ,

2 0 1 5

Network General

ctions to improve staility

ore t*an one conductor per p*a)e

Serie) capacitor

S*ort (ault clearin" ti#e

Sin"le p*a)e autoreclo)in"

%ncrea)e inertia con)tant in t*e "enerator

N t k G l



© A

B B G r o u p - 1 8 -

S e p

2 8 ,

2 0 1 5

Network General

&hunt +eactor

&i#it) o,er ,olta"e)

&i#it) tran)(er o( reacti,e po+er $)uall- t*-ri)tor

controlled'

N t k G l



© A

B B G r o u p - 1 -

S e p

2 8 ,

2 0 1 5

Network General

Neutral reactor apaciti,e couplin" bet+een p*a)e) *elp #aintain arc

at (ault point #akin" % p* auto reclo)in" di((icult

400k tran)po)ed line

0/5 S dead ti#e up to 180 k

400k un tran)po)ed line

1 S dead ti#e up to 0 k

9or lon"er line) nece))ar- to pro,ide reactor) on bot*end) and neutral reactor

%nductance o( neutral reactor : 2B

N t k G l



© A

B B G r o u p - 2 0 -

S e p

2 8 ,

2 0 1 5

Network General

4apacitive 4oupling and &ingle.pole Tripping

L R

A B C A B CC p

C p C p

C e C

eC

e

N t k G l



© A

B B G r o u p - 2 1 -

S e p

2 8 ,

2 0 1 5

Network General

5i6ed 5our.reactor &cheme

L R

A B C A B C

L p L

p L

p

L n

N t k G l

01 network general

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