os-exe3-23-may2011-sr-i-776s21tr-lineprotection-120425095503-phpapp02.ppt

8/18/2019 os-exe3-23-may2011-sr-i-776s21tr-lineprotection-120425095503-phpapp02.ppt

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Classi!a"i#$ #% Ta$s'issi#$ Li$(s

)S*#" Li$(s L($+"* )/M

)M(0i1' Li$(s L($+"* 24)/M

)L#$+ Li$(s L($+"* 24)/M


3/39

T3(s #% %a1l"s i$ "*( "a$s'issi#$s3s"('

)Short circuit faults Frequency

)5*as( 6 G#1$0 %a1l"s 78

)5*as(- 5*as( %a1l"s 8)5*as( 6 5*as( 6G#1$0 %a1l"s 78

)9 5* %a1l"s 28

)Open circuit faults

)B#/($ !#$01!"#

)O($ 1'(


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5#"(!"i#$ S!*('(

)Protection Scheme for Transmission lines as per CBIP

guidelines

; S*#1l0 *aF (la3s

; A1"# (!l#s( (la3 s1i"a?l( %# @ *>9* =i"* 0(a0li$(!*a+i$+ a$0

s3$!*# !*(!/ (!l#s1(.

)Types of main Protections:

; O


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)Requirements of distance protection:

; S*all *a


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If = E/(ZS+ZL)

The reach of over current relay is function of SourceImpedance which varies consideraly! ma"in# it difficult

to #et fast and Selective trippin# $

E ZS ZL

If

XXXXX

Over Current Protection


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5*as( C#'ais#$ 5#"(!"i#$

) C1($" 5*as( !#'ais#$ "3(

) S1i"a?l( %# #(a"i#$ =i"* 5LCC

) Hi+* s($si"i


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Dis"a$!( 5#"(!"i#$

)Type of distance relays)Reactance

) S1i"a?l( %# s*#" li$(s) N#" ((!"(0 ?3 %a1l" (sis"a$!() E(!"(0 ?3 #=( s=i$+s

) N#$ 0i(!"i#$al

)Impedance

) S1i"a?l( %# '(0i1' li$(s) N#$ 0i(!"i#$al) E(!"(0 ?3 %a1l" (sis"a$!(

)Mho

) Di(!"i#$al) L(as" ((!"(0 ?3 #=( s=i$+s) L(ss ((!"(0 ?3 %a1l" (sis"a$!(


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I'(0a$!( R(la3 C*aa!"(is"i!s

L#a0A(a

RZ@

Z2Z9


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MHO (la3 !*aa!"(is"i!

The characteristic of a mho impedance element , when plotted

on a R/X diagram, is a circle whose circumference pass throughthe origin .

Ψ

Ψ = relay characteristic angleR

X


11/39

OFF set MHO characteristic

Under close up faults, when the voltage is near to zero then

!" will not operate# $he %ho characteristic can &e shiftedtowards origin for operation of close up faults# $his is 'now

as "(( set !"#

Ψ

Ψ= relay characteristic angle

R

X


12/39

L#a0

Lenticular characteristics

The characteristic of lenticular mho will be useful to

provide maximum load transfer condition with

maximum fault resistance coverage.

Ψ

Ψ= relay characteristic angle

Z-1

Z-

Z-!

Z-!

R


13/39

Quadrilateral characteristic

"t is a basicall# a reactance rela# superseded with

controlled resistive reach.

Ψ

Ψ = relay characteristic angle

Z-1$

Z-1

Z-

Z-!

Z-!


14/39

Zones of %istance &rotection'

Z)

Z*Z+

SI* SETTI, &-IL.S.&-

Z.E 01 ' 23 4 of protected line

Z.E 05 ' 133 4 of protected line + 53 4 of shortest ad6$ line

section or 1334 + 734 of transformer impedance

Z.E 08 ' 1334 of protected line + 133 4 of lon#est ad6$ line or 133 4 + 1334 of transformer impedance$

Z.E 9: To cover close up ac"9up non9directional faults #enerally

reverse reach will e provided in relays (134)#

X X X X X X


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Ters associated !ith distance "rotection

;each'Reach is the i%pedance of the tr# line up to which the

distance relay protects the line fro% the faults#

over reach Relay %easured i%pedance less than the actual fault

I%pedance# i#e effective reach of the relay increases


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5aall(l C#'($sa"i#$)N(!(ssi"3 #% aall(l !#'($sa"i#$:

F# "*( %a1l" #$ "*( aall(l li$(, %a1l" !1($" als# %(0 %#' *(al"*3 li$( a$0) "*is !1($" ass "*#1+* +#1$0. T*is !1($" !*a$+(s "*( '1"1al) i$01!"a$!( a$0 i$ "1$ !a1s(s (la3 '(as1i$+ i'(0a$!( "# i$!(as( a$0

) is '#( "*a$ a!"1al %a1l" i'(0a$!(.

T*is ((!" =ill ?( !#'($sa"(0 ?3 !#$$(!"i$+ $(1"al !1($" #% "*( li$( "#) aall(l li$(.

T*is !#'($sa"i#$ =ill $#" =#/, i% "*( aall(l li$( $(1"al !1($" is '#() "*a$ li$( $(1"al !1($".


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Z.E 9 I *-;*TE;ISTI*S

Should isolate the faulted section instantaneously

Should cover protected circuit -fault resistance with so%e%argin to ta'e care of errors in %easure%ent

Selective phase tripping for )ph to ground faults for

auto reclose of the &rea'er#

(ast operation with secured directional discri%ination#

Should &e sta&le in the presence of

)# (ault resistance, arc resistance and tower footing resistance

*# .ower swings+# !eavily loaded condition

/# In feed condition

0# Errors in 1$, 12$ and 1$ saturation

3# $ransients in 1$ - 12$


19/39

Z.E9II *-;*TE;ISTI*S

%elayed trippin# and non selective phase trippin#$

&rovide ac" up protection for part of ad6acent line$

Trip the faulty line instantaneously usin# carrier aided trippin#$

Time delay is normally 733ms

Z.E9III *-;*TE;ISTI*S

This provides ac" up protection for the ad6acent lines or

transformer


Z.E 0I *-;*TE;ISTI*SThis provides ac" up protection for the station faults

It is normally in the reverse direction



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%istance Schemes'

1 $ & $ < $ ; 99 &ermissive under reach scheme

5$ & $ . $ ; 99 &ermissive .ver ;each scheme

8$ L.*>I, S*-E?E

:$ @E> E% AEE%


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*;;IE; S*-E?ES 9 & < ;

1!455EL

Z)4

Z*4

Z)6

Z*6

4

6

14RRIER

REL47REL47

(ault

$rip = Z) 8 Z*#1R8Z+#$+8Z*#$*

1S = Z)

Under reaching zone sends carrier signal


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*;;IE; S*-E?ES 9 & . ;

REL47

Z)4

Z*4

Z)6

Z*6

4

6

14RRIER REL47

(ault

$rip = Z)8Z*#1R8 Z*#$*8Z+#$+

1S = Z*

"ver reaching zone sends carrier signal


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@E> E% AEE%

It is a condition which occurs on a line when no current infeed

from the line terminal or when the current infeed is low dueto wea" ,eneration ehind protection$

If the fault current infeed is too low to operate the protection

at the wee" end! the followin# mi#ht occur! dependin# on

The selected communication scheme$

In permissive schemes or loc"in# schemes * at wee" infeed

end may fail to trip instantaneously! due to no relay operation

in the wea" end$

In permissive over reach scheme! if the fault is in Zone 5 from

stron#er end! oth *s may fail to trip instantaneously due to

no relay operation in the wea" end$


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@E> E% AEE% L.,I* I &$.$;

Aault in Z5+


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TRANSIENT FAULTS -CHARACTERISTIC

1hracterised &y disappearnance after Short dead ti%e and aredisapper without any action &eing ta'en#

TYPES OF TRANSIENT FAULTS

)# Lightning stro'es resulting in fashovers*# 1onductor swinging due to high winds

+# 6ird fault

/# $e%porary contact with foreign o&9ects li'e tree etc#

4&out :0 ; of faults on trans%ission lines are transient in nature


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SEMI PERMANENT FAULTS

$his type of faults rea%ple is a tree falling on the line and getting &urnt

up &y the arc when the line is re energised#

)?; of the reclosures are successful with second shot#

!owever this can cause unnecessary wear on E!2 16s#

$herefore second shot is not reco%%ended for E!2 Syste%s#


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DEAD TIME :

$he ti%e &etween the autoreclose sche%e &eing energisedand the operation of the contacts which energise the 16 closing

1ircuit#

RECLAIM TIME

$he ti%e following a successful closing operation %easured

fro% the instant the 4@R relay closing contacts %a'e, which

%ust elapse &efore the autoreclose relay will initiate reclosing

se


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CHOICE OF RECLAIM TIME

$he reclai% ti%e %ust not &e set to such a low value thatthe intended operating cycle of the &rea'er is e>ceeded

when two fault incidents occurs close together#

for e>a%ple the reclai% ti%e for a air &last circuit &rea'ers

%ust allow ti%e for air pressure to recover to its nor%alvalue#

CHOICE OF DEAD TIME

ead ti%e for E!2 syste% lower li%it is decided &y

deAionising ti%e, upper li%it is decided &y transient sta&ility

and synchronis%


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Poer Sing

)5#=( S=i$+s a( 0is"1?a$!(s i$ s3s"(' 01( "#


31/39

R

Z@

Z2

Z9

.ower

swing

detection

zones

Poer Sing detection

$i%e ta'en &y fault locus to cross the power swing

detection zones is %ore than /?A0?%s, then it is called

power swing#

F F il F "i


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F1s( Fail1( F1$!"i#$) !symmetrical measuring "oltage failure:

S1?s"a$"ial as3''("3 #% '(as1(0


33/39

S=i"!* #$ "# %a1l"

) T*is %(a"1( #


34/39

O$( a$0 Hal% B(a/( S!*('(

1'tA) 1'tA*

6usA)

6usA*

2@

Stub Protection


35/39

DEF 5#"(!"i#$

)I" #


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L#!al ?(a/( ?a!/ 1 #"(!"i#$

)I" is "*( s(!#$0a3 #"(!"i#$

) T# #


37/39

Di(!" "i S!*('(

) I" is (J1i(0 "# "i #"*( ($0 ?(a/(s =i"*#1" a

) !*(!/i$+ "*( s"a"1s a" #"*( ($0 01i$+ %#ll#=i$+) !#$0i"i#$s:

; O(a"i#$ #% #


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O


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