Sect 02 power system protection

8/13/2019 Sect 02 power system protection

1/25

Rev 0 POWER SYSTEM PROTECTION March 1997

SECTION 2

MEASUREMENT

Contents

MEASUREMENTS - GENERAL........................................................................2Direct Measurement.......................................................................................2Indirect Measurement.....................................................................................3Instrument Accuracy.......................................................................................4

VOLTAGETRANSFORMERDESIGN.....................................................................5CURRENTTRANSFORMERDESIGN.....................................................................6TERMINALMARKINGS.......................................................................................8SPECIALDANGERSWITHCURRENTTRANSFORMERS.........................................9BURDEN..........................................................................................................11

Calculation of an instrument transformer burden.......................................11Location of CTs and VTs..............................................................................12Instruments...................................................................................................12

CURRENT AND VOLTAGE TRANSFORMERS FOR PROTECTION......14CURRENT TRANSFORMERS.....................................................................14

Design...........................................................................................................14!eration......................................................................................................1"!en#Circuited Current Transformer..........................................................1$

%&ort#Time 'actor........................................................................................1(Accuracy Limit 'actor..................................................................................1(%!ecification of Current Transformers........................................................2)

*ated %econdary Current.............................................................................2)%econdary +inding Im!edance....................................................................21

,rimary +indings.........................................................................................21A!!lication...................................................................................................21-ffect of CT Magnetising Current on *elay %etting....................................23uadrature or Air#/a! Current Transformers............................................23%ummation Current Transformer.................................................................23

VOLTAGE TRANSFORMERS.....................................................................23

Accuracy.......................................................................................................24,rotection.....................................................................................................24*esidual Connection.....................................................................................24

CAPACITORVOLTAGETRANSFORMERS...........................................................25

Section 2 - Measureent Pa!e 2 - 1


2/25


Measurements - GeneralI !.". #$%&' ()(*&+( ,* ,( &"&((!') "$*,-!) *$ +$,*$' */& 0$*!& "-''&*(

#$%&' ! (,+,!' -!*,*,&( , */& 0!',$-( #!'*( $ */& ()(*&+. T/,( ,( $& ) */&-(& $ ,(*'-+&*( 7 */!* ,( ) ,,"!*, 0$*+&*&'( !++&*&'( %!**+&*&'( &*".

T/& (!+& +&!(-'& -!*,*,&( !'& !($ -(& *$ #'$*&"* */& ()(*&+ ) +&!( $'&!)( %/,"/ !'& &0,"&( *$ &*&"* %/& !) $ */& -!*,*,&( ,( $, $-*(,& */&

#'&&*&'+,& ,+,*. T/&) ,,*,!*& %/!*&0&' !-*$+!*," !"*,$ ,( &"&((!') *$'&(*$'& */& (,*-!*,$ $' ,("$&"* !-*) $' $0&'$!& !##!'!*-(.

A+$(* ! &&"*',"! ,(*'-+&*( ! '&!)( & $' */&,' !"*,$ $+&!(-'&+&*( $ 0$*!& $' "-''&* $' "$+,!*,$( $ */& *%$. M&!(-'&+&*( $'&-&") !'& $*!,& '$+ !!)(, ! 0$*!& +&!(-'&+&*.

Direct Mes!re"ent

V

A

V

1

2

"

12

"

Single Phase

Three Phase

Clip-on Ammeter

(any phase)

Three Phase

Single Phase

(a) Voltage

(b) Current

S#itch

Positions

1 R - Y

2 Y - $

" $ - R

FIGU! "#$ - %I!CT M!ASU!M!&T

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3/25


D,'&"* +&!(-'&+&* $ "-''&* , ! (,&7#/!(& ",'"-,* ,( $*!,& ) #!",*/& ,(*'-+&*;( "-''&*7$#&'!*& "$, , (&',&( %,*/ ! +!, "$-"*$' (/$% ,F,-'& 2.1:. I */& 37#/!(& "!(& ,* ,( $* #$((,& *$ (&&"* #/!(&( $' "-''&*+&!(-'&+&* -&(( "-''&* *'!($'+&'( !'& -(&. I* %$- $*/&'%,(& &&"&((!') *$ '&! &!"/ #/!(& *$ "$&"* */& !++&*&' ! */,( %$- $* &

!""*!&. S&&"*,$ %,*/ */& -(& $ "-''&* *'!($'+&'( ,( (/$% -&';I,'&"* M&!(-'&+&*; , F,-'& 2.2. A*&'!*,0&) */'&& (!'!*& !++&*&'(+!) & -(&.

T/& "-''&*( , */& (!'!*& #/!(&( "! /$%&0&' & +&!(-'& ,&&*)) -(& $ ! ",#7$ *)#& !++&*&'. D,&'&* !++&*&' ,(*'-+&*( "! -& ,*$ */& *$( *$ ,0& "-''&* '!&( '$+ 1*'&+& !-* "-''&*(. T/,( *$$ ,( $* #'!"*,"! &>"* $' */&,/*&(* ",'"-,*(.

In#irect Mes!re"ent

T$ $0&'"$+& */&(& $?&"*,$( ,,'&"* +&!(-'&+&* ,( &+#$)&. T'!($'+&'(!'& -(& $* $) *$ ("!& $% */& -!*,*,&( !"*-!) +&!(-'& -* !($ *$,($!*& */& ,(*'-+&* $' '&!) '$+ */& +!, ()(*&+ 0$*!&. S-"/*'!($'+&'( %/,"/ !'& &(,& (#&",,"!) $' */,( #-'#$(& !'& $% !(,(*'-+&* *'!($'+&'(.

I(*'-+&* *'!($'+&'( !'& $ *%$ *)#&( 7 ;0$*!& *'!($'+&'(; VT: !;"-''&* *'!($'+&'(; CT:. T/&) !'& (/$% ,!'!++!*,"!) , F,-'& 2.2 $'

$*/ (,&7#/!(& ! 37#/!(& ()(*&+(. F$' 37#/!(& */&'& +!) & &,*/&' */'&&(!'!*& (,&7#/!(& VT( %,*/ */&,' '!*,$( !?-(*& $' */& (*!' "$&"*,$: $'&(& ! 37#/!(& -,* %/,"/ ,( +$'& -(-!. C-''&* *'!($'+&'( !'& !%!)(

#'$0,& !( (!'!*& (,&7#/!(& -,*(.

T/& (&"$!') 0$*!&( ! "-''&*( +!) & "/$(& !( &(,'& -* , #'!"*,"&*/& VT (&"$!') 0$*!& ,( -(-!) 11


4/25


(a) Single Phase

(b) Three Phase

Current

O%erate&

Re'a(s

Current

O%erate&Re'a(

)o'ta!e

O%erate&

Re'a(Wattetric

Re'a(

)o'ta!e

O%erate&

Re'a(

A

V

V

A

Wattetric

Re'a(VT $$'V

VT $$'V$$'V (line)

CT

( or $A)

CTs

( or $A)

FIGU! "#" - I&%I!CT M!ASU!M!&T )IT* I&STUM!&T TA&SF+M!S

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Instr!"ent Acc!rc$

S,"& */& #-'#$(& $ ,(*'-+&*( ! '&!)( ,( *$ +$,*$' */& !"*-! "$,*,$(, */& +!, #$%&' ,& ,* ,( &"&((!') */!* VT( ! CT( ''$-"& */$(&"$,*,$( *$ ! (*#&7$% ("!& !( !""-'!*&) !( #$((,&. T/!* ,( *$ (!)*/&,' 0$*!& '!*,$ $' "-''&* '!*,$ +-(* & "$''&"* ! "$(*!* $0&' */&,' %/$&'!& $ $#&'!*,$@ */&) +-(* $* ,*'$-"& --& #/!(& (/,* %/,& $, ($,+#$'*!* $' %!**+&*&'(:@ ! */&) +-(* ''$-"& -!!"& "$,*,$(&>!"*).

T/& &>*&* *$ %/,"/ */&(& "$,*,$( !'& +&* &*&'+,&( */& !""-'!") "!(( $*/& ,(*'-+&* *'!($'+&'. A ,(*,"*,$ ,( '!% &*%&& ;+&!(-',; !;#'$*&"*,0&; *)#&(. F$' +&!(-'&+&*( */& !""-'!") %,*/, ! ! ,**& !$0&*/& $'+! %$', '!& ,( ,+#$'*!* -* !""-'!") , */& $0&'"-''&* ! !-*'!&( $ "-''&* $&( $* +!**&'. O */& $*/&' /! ! #'$*&"*,0& CT +-(*&,0&' !""-'!*& "-''&*( , */& !-* '!& %/&'&!( !""-'!") , */& %$','!& ,( -,+#$'*!*. T/,( ,0&( ',(& *$ *%$ ,&'&* &(, "$"*(.

Section 2 - Measureent Pa!e 2 - *


5/25


T/& "!((&( $ !""-'!") !'& !, $% ) B',*,(/ S*!!'(. F$' &!"/ *)#&,&'&* '!&( $ !""-'!") !'& (#&",,& $' +&!(-'&+&* ! $' #'$*&"*,0&*'!($'+&'( !""$', *$ */& #-'#$(& $' %/,"/ */&) !'& *$ & -(&. T/&'!&( !'& !( $$%(

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M&!(-'&+&*


6/25


0!',&( %,*/ ,&'&* +!-!"*-'&'(.

Current Trans,ormer %esign

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B!'7*)#& CT( !'& &&'!) -(& %/&&0&' */& "-''&* '!*,$ &.. 15


7/25


FIGU! "#0 - 1A T.P! CT S*+)I&G C+&STUCTI+& %!TAI/

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8/25


Terminal Mar2ingsT/& *&'+,!( $ ! CT (/$- & +!'& !( ,,"!*& , F,-'& 2.4. T/& #',+!')"-''&* $%( '$+ P1 *$ P2 ! ,* ,( (*!!' *$ #-* P1 &!'&' *$ */& ",'"-,*

'&!&'. T/& (&"$!') "-''&* $%( '$+ S1 *$ S2 */'$-/ */& -'&.

P1

P2

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P2

S 1

S 1

S 2

S 2S "

S *

a. Sin!'e Secon&ar(

- No Ta%%in!s

/. Sin!'e Secon&ar(

With Ta%%in!s

P1

P1

P 2

S 1

S 1

2C

P2

S 2

S 2S "

S *

C 1

c. Mu'ti Secon&ar(

Win&in!s

&. Priar( in

Sections

FIGU! "#( - CT T!MI&A/ MA3I&GS

Section 2 - Measureent Pa!e 2 -


9/25


Spe4ial %angers 5ith Current Trans,ormersW/& ! CT (&"$!') ",'"-,* ,( "$(& ! "-''&* $%( */'$-/ ,* %/,"/ ,( ! &>!"*

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10/25


T/& !&' '$+ ! $#&7",'"-,*& CT ,( *%$$. I* "! #'$-"& &*/! 0$*!&(! ($ ,( ! 0&') '&! !&' *$ #&'($&. T/& /,/ 0$*!& !"'$(( */& (&"$!')%,, "$- !($ "!-(& ,(-!*,$ !,-'& , */!* %,, &!, !* &(* *$,!""-'!") ! !* %$'(* *$ -'$-* $' ,'&.

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11/25


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12/25


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13/25


;ar

;ar

4os

4os

*!+#& ! CT '!*,$ $ 3


16/25


O0ertion

A ''&(&*!*,$ $ ! ',7*)#& "-''&* *'!($'+&' ,( (/$% , F,-'& 2.9. R2,(

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Section 2 - Measureent Pa!e 2 - 1,


17/25


Vb

I""

V"I"

Ie

I$

FIGU! "#$' V!CT+ %IAGAM +F A I&G-T.P! CU!&T TA&SF+M!

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R2+ Rb+jXb 6


VR2+ Rb+jXb

12


18/25


00+ 010 01+ 020 02+

20

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,0

0

100

120

1*0

)o'ta!e-)

2.

Ma!netisin! Current Ie 2%eres.

)3P

+04

104 increase

increase

FIGU! "#$$ - CT MAG&!TISI&G C*AACT!ISTIC

O0en-Circ!ite# C!rrent Trns*or"er

I */& ,+#&!"&Rb+jXb,( 0&') /,/ */& */& 0$*!& "!"-!*& '$+I2 (R2+ Rb+jXb) %$- & 0&') !'& %& !$0& &&7#$,* 0!-& !Ie%$- &"$+& (,,,"!*) !'& , */& !+#&'&7*-' !!"& &-!*,$

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-* , #&'/!#( 11


19/25


Sort-Ti"e Fctor

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20/25


S0eci*iction o* C!rrent Trns*or"ers

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21/25


Secon#r$ %in#in, I"0e#nce

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Section 2 - Measureent Pa!e 2 - 2+

Sect 02 power system protection

Documents

Transcript of Sect 02 power system protection