SIZING+GROUNDING+TRANSFORMERS+AND+RESISTORS

SIZING GROUNDING TRANSFORMERS AND RESISTORS

TABLE OF CONTENTS

1.0 2.0 3.0 4.0 5.0 6.0 7.0

PURPOSE PURPOSE & SCOPE.......... SCOPE................ ............. .............. .............. ............. ............. .............. ............. ............. .............. .............. ............. ............. ................. ......................... ............... DEFINITION DEFINITIONS....... S.............. .............. ............. ............. .............. .............. ............. ............. .............. ............. ............. .............. .............. ............. ................... ............................... .................. APPLICABI APPLICABILITY. LITY........ ............. ............. .............. .............. ............. ............. .............. ............. ............. .............. .............. ............. ............. .............. .............. ............. ................ ............. ... RESPONSIBIL RESPONSIBILITIES... ITIES.......... .............. .............. ............. ............. .............. .............. ............. ............. .............. ............. ............. .............. .............. ............. ........................ .................. PROCEDURE PROCEDURE / REQUIREMENT REQUIREMENTS....... S.............. .............. ............. ............. .............. .............. ............. ............. .............. ....................... ............................... ............... REFERENCES.. REFERENCES........ ............. .............. ............. ............. .............. .............. ............. ............. .............. ............. ............. .............. .............. ............. ................. ............................ ................. ATTACHMEN ACHMENTS..... TS............ .............. ............. ............. .............. .............. ............. ............. .............. ............. ............. .............. .............. .................... ................................. ....................

1.0 PURPOSE & SCOPE

T!" #$%'()$' %)*+!,'" *' -'*%( *% ' %++%'( %$ #$'#$*!%, % *' ','$*%$   N')*$+ $%),(!, ,( T$,"%$-'$ N')*$+ $%),(!, ,( R'"!"*%$ S!!, ,( !" !,*',('( *% "")$' ),!%$-!* % ++ ") ""*'-". T!" #$%'()$' ('#!*" $%),(!, "'-'" " '++ " "!!, % $%),(!, ')!#-',* %$ *' %++%!, '+'*$!+ ""*'-" ,( ')!#-',* • M!, ','$*%$8 • M!, T$,"%$-'$8 • U,!* A)9!+!$ T$,"%$-'$8 S*$*)# T$,"%$-'$8 • L%:;%+*' L%( C',*'$ T$,"%$-'$8 • D!'"'+ ','$*%$ 8 • AC ,( DC UPS ""*'-"

2.0 DEFINITIONS Generator Neutral Grounding T' #)$#%"'" % ','$*%$ ,')*$+ $%),(!, *$%)

, !-#'(,' $' *% +!-!* *' (-' * *' #%!,* % )+*8 +!-!* *$,"!',* %='$: =%+*'" ,( #$%=!('  "',"!*!=' -'," % ('*'*!%, %$ !,")+*!%, ('*'$!%$*!%,. T'$' $' *% '#*+' -'*%(" % $%),(!, ),!* %,,'*'( ','$*%$"? $'"!"*%$  $%),(!, ,( $'"%,,* <$'*%$> $%),(!,. Resistance Grounding A $'"!"*,' $%),('( ""*'- )"'"  $'"!"*%$ !, *' ,')*$+:*%:$%),( !$)!* *% +!-!* *' -9!-)=+)' % "%$* !$)!* )$$',* ()$!,  +!,' *% $%),( )+* +!-!*!, *' )$$',* ,( $'()!, *' '9*',* % (-' *% ')!#-',* )"'(  *' '*!, ,( -',!+ "*$'""'" ','$*'(  *' "%$* !$)!* )$$',*" Low Resistance Grounding I,  +% $'"!"*,' $%),('( ""*'- *' =+)' % $'"!"*,' !" )")++ "'+'*'( "% ** *' $%),( )+* )$$',* !" +$' ',%) *% *$!# #$%*'*!=' ('=!'" "'+'*!='+8 '* +% ',%) *% +!-!* (-' *% ')!#-',* High Resistance Grounding I,  ! $'"!"*,' $%),('( ""*'- *' =+)' % $'"!"*,' !" "'+'*'( "% ** !* !" % ")!!',* =+)' *% +!-!* )+* )$$',*" *% ='$ +% =+)'"8 )")++ ')+ *% *' *%*+ $!, )$$',* %  *' ""*'- Resonant (Reactor) Grounding T!" $%),(!, "'-' !" "!-!+$ *% $'"!"*,' $%),(!, '9'#* *' $'"!"*%$ !" $'#+'( !*  $'*%$ ')!=+',* *% *' ""*'- $!, )$$',* *% %$-  *),'( <$'"%,,*> !$)!*. 3.0 APPLICABILITY

T!" #$%'()$' !" ##+!+' *% ++ #$%@'*". 4.0 RESPONSIBILITIES 4.1 L'( E+'*$!+ E,!,''$ 

T' L'( E+'*$!+ E,!,''$ !" $'"#%,"!+' %$ "!!, *' $%),(!, *$,"%$-'$" ,( $'"!"*%$". 5.0 PROCEDURE / REQUIREMENTS 5.1 E)!#-',* $%),(!, R')!$'-',*" 5.1.1 M!, ','$*%$ 

M!, ','$*%$ "++ +" ' ! $'"!"*,' $%),('(. M!, T$,"%$-'$  5.1.2 M!, *$,"%$-'$ %$ *' ','$*!, #+,* "++ +" ' "%+!(+ $%),('( * *' ! "!('. L% "!(' %,,'*'( *% *' ','$*%$ !" +" ('+* %,,'*'(. N% "#'!+ ')!#-',* !" $')!$'( %$ ! "!(' $%),(!,. 5.1.3 U,!* A)9!+!$ T$,"%$-'$  U,!* )9!+!$ *$,"%$-'$ %,,'*'( *% *' ','$*%$ +'(" "++ +" =' *' ! "!(' ('+* %,,'*'(. L% "!(' % *!" *$,"%$-'$ !" ','$++ ' %,,'*'( ,( "++ ' +% $'"!"*,' $%),('( ++%!,  -9!-)- % 1000A $%),( )+* )$$',*. $%),(!, $'"!"*%$ (!$'*+ %,,'*'( *% *' ,')*$+ "++ ='  -!,!-)- % 10:"' $*!,. L% $'"!"*,' $%),(!, "++ +" ' )"'( ),+'"" "#'!!++ $')!$'(  *' +!',*. C"'"8 '$' +% "!(' % *!" *$,"%$-'$ !" +"% ('+* %,,'*'(8 ()' *% #"!,8 $%),(!, , % T:*#' %$ !: *#' !*  $'"!"*%$ ++%!,  1000A -9!-)$%),( )+* "++ ' )"'(. R*!, % *' $%),(!, ')!#-',* "++ %  -!,!-)- %  10 "'. ', *' %,*$* $')!$'"  (!'$',* -'*%(8  +)+*!%, "!-!+$ *% A**-',* 7.2 "++ ' #'$%$-'(. 5.1.4 S*$*)# T$,"%$-'$ 

S*$*)# *$,"%$-'$8 ', )"'(8 - =' '!*'$ ('+* %$ ' %,,'*!%, %$ ! %$  +% "!(' !,(!,. F%$ ! "!('8 ' %,,'*!%,8 ,')*$+ "++ ' "%+!(+ $%),('(. F%$ +% "!(' ' %,,'*!%,8 ,')*$+ "++ ' +% $'"!"*,' $%),('(. F%$ +% "!(' ('+*8 $%),(!, , % T:*#' %$ !: *$,"%$-'$" !*  $'"!"*%$ ++%!,  1000A -9!-)- $%),( )+* )$$',*. R*!, % *!" ')!#-',* "++ %  -!,!-)% 10 "'. 5.1.5 L%( C',*'$ T$,"%$-'$  T$,"%$-'$ ''(!, +% =%+*' +%( ',*'$ "++ ' ('+*/':"%+!(+ $%),('(8 ,')*$+8 ),+'"" "#'!!++ $')!$'(  *' +!',* *% ' (!'$',*. 5.1.6 D!'"'+ ','$*%$" D!'"'+ ','$*%$"8 ', #$%=!('( "++ ' +% $'"!"*,' $%),('( * *' -'(!)=%+*' ,( "%+!(+ $%),('( * +% =%+*' (!"*$!)*!%,. L% $'"!"*,' $%),(!, "++ ++%  -9!-)- % 1000A $%),( )+* )$$',*. $%),(!, $'"!"*%$ (!$'*+ %,,'*'( *% *' ,')*$+ "++ ='  -!,!-)- % 10 "' $*!,. 5.2 ','$*%$ N')*$+ $%),(!, C+)+*!%, M'*%(

A**-',* 7.1 #$%=!('"  $'',* #$%@'* +)+*!%, %$ "!!, *' ','$*%$ ,( *$,"%$-'$ $%),(!, *$,"%$-'$. T' %++%!, %,"!('$*!%, -)"* ' ,+'( ', $'%--',(!, ,( "'+'*!,  -'*%( % ','$*%$ $%),(!,. 1> T' (-' * *' #%!,* % )+* !" $'*+ $'()'( ', *' ),!* !" $'"%,,* $%),('( " %-#$'( *% $'"!"*%$ $%),('(. 2> S)$'" %, *' ! =%+*' ""*'- !++ ,%* ##'$ '*'', ','$*%$ ,')*$+ ,( $%),( ')"' % *' ':('+* *$,"%$-*!%, % *' -!, *$,"%$-'$. 3> T$,"!',* %='$=%+*'" %, *' ),)+*'( #"'" $' +!-!*'(  $'"%,,* $%),(!,. A$!, %$ )$$',* ")$'" $' $'()'(  $'"%,,* $%),(!,. T!"  #$'+)('" *' #%""!!+!* % *$,"!',* %='$=%+*'" ()' *% $!, $%),(". 4> T' ##'$,' % '$% "')',' =%+*' %, *' *$,"-!""!%, ""*'- %$  +!,' *% $%),( )+* !-#$'""'"  *$,"!',* =%+*' %, *' ','$*%$ ""*'-. T!" =%+*' !"  ),*!%, % *' #!*!=' %)#+!, $'*,' !, *' ),!* "*'#:)# *$,"%$-'$  ,( *' '$% "')',' !-#'(,' % *' ','$*%$ ""*'-. T' *$,"!',* =%+*' %, *' ','$*%$ ""*'- <#"' *% $%),( EO> !++ ' !'$ !, -,!*)(' !* $'"%,,* $%),(!, *, !* $'"!"*%$ $%),(!,. T!" =%+*' -)"* ' %,*$%++'( !*!, '#*+' +!-!*"  *' #$%#'$ "'+'*!%, % *' %!+ %,"*,* % *' $'*%$. 5> R'"%,,* $%),(!, #$%=!('" !,$'"'( "',"!*!=!* %$ ('*'*!%, % !,")+*!%, ('*'$!%$*!%, * , +%*!%, !, *' ','$*%$ ""*'- ,( ,')*$+ %,,'*'( ##$*)". 6> ', $'"!"*,' $%),(!, !" )"'(8 *'$' !"  ('( %,' '$' )+*" ,,%* ' ('*'*'(. T!" ('( %,' !"  !$+' * *' ""*'- ,')*$+ %,',*$! !* ++ '$% "')',' )+* =%+*'". B )"!, *' $'"%,,* $%),(!,8 *!" ('( %,' , ' %"'*  !,*$%()!,  =%+*' *% (!"#+' *' ""*'- ,')*$+. T!" #$%'()$' ")--$!'" *' $')!$'( (* ,( *' +)+*!%," ** -)"* '  #'$%$-'( *% "#'! *' (!"*$!)*!%, *$,"%$-'$8 $'*%$ %$ $'"!"*%$ $*!,". 5.3 R')!$'( D* ENERATOR 5.3.1

 #"'

M;A8 *$''

E C E30 E%

5.3.2

 P"' *% #"' =%+*' ;  S!,+' #"' *% $%),( #!*,' --   '$% "')',' ,%$-+ *!$( $-%,! =%+*' ;  '$% "')',' ,%$-+ ),(-',*+ $')', =%+*' ;

   

MAIN TRANSFORMERS  #"'

M;A8 *$''

 N N)-'$ % *$,"%$-'$" C  #"' *% $%),( #!*,' <',. "!('> --  C*  H! *% +% "!(' !,(!, #'$ #"' #!*,' --  EHO  H! "!(' '$% "')',' =%+*' %$  )+* %, *' ! "!(' % *' *$,"%$-'$ ;

5.3.3

UNIT STATION SER;ICE TRANSFORMER

 N)



C)

 S!,+' #"' *% $%),( #!*,' <',. "!('> -- 

5.3.4

 



M;A8 *$'' #"'  

ISOLATED PHASE BUS

C

5.3.5

N)-'$ % ),!* "**!%, "'$=!' *$,"%$-'$"

 S!,+'

 T%*+ "!,+' #"' *% $%),( #!*,' -- 



SURE CAPACITORS

C" -- 



S!,+' #"' *% $%),( #!*,' <',. "!('>



Eφ;



M9!-)- '#*+' =%+*' *' ""*'- ')!#-',* , *' !*%)* (-' 

5.4 C+)+*!%," F%$ R'"%,,* $%),(!,

 E  g  

3

E'

 ','$*%$ #"' *% ,')*$+ =%+*' ;

C

 T%*+ ""*'- #!*,'  3. -- 

 T%*+ ""*'- #!*!=' $'*,'  %-"

ω 



1012

1





⋅ C  %$ 2π   ⋅  f   ⋅ C 

E' ⋅



1 

I

 S"*'- #!*!=' )+* )$$',*  -#"



L

 E'*!=' !,()*!=' $'*,' %$ $'"%,,* $%),(   %-"



ELP  D!"*$!)*!%, *$,"%$-'$ #$!-$ =%+*' ≥  E' ; =!++'



ELS  D!"*$!)*!%, *$,"%$-'$ "'%,($ =%+*' 120/240 ;



TR G;A



C%,*!,)%)" (!"*$!)*!%, *$,"%$-'$ $*!,  I ⋅ E' ⋅ 10

:3



I ,% ('+ !" !,*',('( %$ *' ),!* *$!#8 *!" $*!, , ' $'()'(  *' *%$" $%- *' %++%!, *+' TIME

FACTOR

1 M!,)*' 5 M!,)*'" 30 M!,)*'" 1 H%)$ 2 H%)$" *



 

0.212 0.357 0.55 0.625 0.714

C#!*!=' %)#+!, $'*,' '*'', ! ,( +% "!(' % 

1012 *' -!, *$,"%$-'$  %-" LS

2π   ⋅  f   ⋅ C t 

 A"")-'( *%*+ +%""'" %$ *' $'*%$ 5





R



E'*!=' '$% "')',' $'"!"*,' !, *' ','$*%$  ,')*$+ %$ *!" +%"" 

100

3 ⋅  X  L ⋅

LS 



%-" G.E% 

N')*$+ =%+*' (!"#+'-',* ()' *% ','$*%$"

100 ),(-',*+ '$% "')',' =%+*'   LS 

⋅ E og 



; ER



N')*$+ (!"#+'-',* ()' *% )+* %, *' ! "!('

 E  HO ⋅ R % *' -!, *$,"%$-'$ 

 R −  j ⋅  X ct 



; Eφ



P"' *% $%),( =%+*' %$  $%),( )+* %, *' ! % *' -!, *$,"%$-'$  E'  GE%  ER



; I Eφ +)+*'( %=' !" -%$' *, *' -9!-)- '#*+' =%+*' !,$'"' *' $'*%$ +%""'" *%  !'$ =+)' ,( $'+)+*' R8 GE% ,( ER  LS



R'*,' !, *' "'%,($ % *' (!"*$!)*!%, *$,"%$-'$ 

( E  LS  ) 2  X  L ⋅ ( E  LP  ) 2



%-" RLS



R'"!"*,' !, *' "'%,($ % *' (!"*$!)*!%, *$,"%$-'$ 

 X  LS  ⋅

 LS  100



%-"

GL



C%!+ %,"*,*  100 LS

 I c ⋅ I"

 S'%,($ )$$',*  -#"

 E  LP   E  LS 

 E  ge ⋅ ;"

 S'%,($ =%+*'  ;



 E  LS   E  LP 



LSG;A  R'*%$J" G;A  G;A $F  F)+* $'"!"*,' %-"

I" . ;" .10:3

 

 E  ge IFO

 '$% "')',' )+* )$$',*  -#"

IF

 F)+* )$$',*  3 . IFO -#"

E%



 R + 3 ⋅ r  F 





P'$',*' ,')*$+ =%+*' (!"#+'-',*

 I  FO ⋅ R ⋅ 100 

 E  ge



-#" F

 E,'$ !,*% *' )+*  IF2 . $F **"



C,!, *' =+)' % )+* $'"!"*,' $%- '$% )#$( !, $'"%,+' "*'#"8 +)+*' ,( #+%* F ,( E % !,"* $'"!"*,'.

5.4.1

1K0 H8 N% F)+* O$ N%$-+ C%,(!*!%,"

U"!, *' %=' (!"*$!)*!%, *$,"%$-'$ !* #'$',*' $'*,' <> ')+ *% !-#'(,' <> 

3 ⋅ Z  ⋅ 10 − 2 ⋅ ( E  LP  )

2

TR ⋅ 103

'  %-"

P$!-$ $'*,' 



L3  %-"

T!$( $-%,! $'*,' !, *' ','$*%$ ,')*$+ 3 L





 E 30 g  I30#  -#"

T!$( $-%,! '$% "')',' )$$',* 

 I 30 p ⋅ I30"  -#"

R'*%$ )$$',* 

 j ⋅ 3 ⋅  X  L 3 + 3 ⋅ R L −  j ⋅  X c



 E  LP   E  LS 



;30"  ;



T!$( $-%,! ,%$-+ =%+*' $%"" *' $'*%$ 

I30" . 3



5.5 C+)+*!%," F%$ R'"!"*%$ $%),(!,

 E  g  3

E'

 ','$*%$ #"' *% ,')*$+ =%+*'  ;

C

 T%*+ ""*'- #!*,'  3 -- 

1 

 T%*+ ""*'- #!*!=' $'"!"*,'  %-"

wc

 E  ge ⋅

=





1012 2 ⋅ π   ⋅  f  c



1  X c

I

 S"*'- #!*!=' )+* )$$',*  -#"



I$'

 A"")-!, ,')*$+ )$$',*  I -#"



 E  ge R'

 E)!=+',* $'"!"*,' !, *' ','$*%$ ,')*$+  %-"

E#

 D!"*$!)*!%, *$,"%$-'$ #$!-$ =%+*' ≥ E' ;=!++'

TR



 I req

C%,*!,)%)" (!"*$!)*!%, *$,"%$-'$ $*!,  I$' . E' . 10:3







G;A I ,% ('+ !" !,*',('( %$ *' ),!* *$!#8 *!" $*!, , ' $'()'(  *' *%$" !=', ),('$ $'"%,,* $%),(!,. E"  D!"*$!)*!%, *$,"%$-'$ "'%,($ =%+*' 120/240 ;



 Req ⋅ R"

 $%),(!, $'"!"*%$ !, *' "'%,($  %-"

 E  s ;"

 M9!-)- "'%,($ =%+*'  ;

 I req ⋅ I"

 S'%,($ )$$',*  -#"

R"G;A  G; $F

 E  p

( E  s ) 2

( E  )

2

 p



⋅ E  ge 

 E  p  E  s



$%),(!, $'"!"*%$" G;A  I" . ;" . 10:3



F)+* $'"!"*,' %-"



3 ⋅ r  F  − 3 ⋅ IFO

 '$% "')',' )+* )$$',*  -#"

IF

 F)+* )$$',*  3 -#"

F

 E,'$ !,*% *' )+*  IF2 . $F **"

 E  ge ( Req ⋅  j ⋅  X  x )

( R

eq

−  j ⋅  X c )

. IFO





 I  FO ⋅ 3

−  Req ⋅  j ⋅  X c

( R

eq

E%



 P'$',*' ,')*$+ =%+*' (!"#+'-',*  

−  j ⋅  X c )

 E  ge

C,!, *' =+)' % )+* $'"!"*,' $%- '$% )#$( !, $'"%,+' "*'#"8 +)+*' ,( #+%* F ,( E% !,"* )+* $'"!"*,'. 

⋅ 100 



5.5.1

1K0 H8 N% F)+*8 %$ N%$-+ C%,(!*!%,

U"!, *' %=' (!"*$!)*!%, *$,"%$-'$ !* #'$',*' $'*,' <> ')+ *% !-#'(,' <>

3 ⋅ Z  ⋅ 10 − 2 ⋅ ( E  p ) '

 P$!-$ $'*,'  %-"

TR ⋅ 10

2

3



 E 30 g  I30#

 T!$( $-%,! '$% "')',' )$$',*  -#"

 I 30 p ⋅

3 ⋅ ( Req +  j ⋅  X e ) −  j ⋅  X c



 E  p

I30"

 $%),( $'"!"*%$ )$$',*"  -#"

;30"

 $%),( $'"!"*%$ ,%$-+ =%+*'  ;

 E  s



 I 30 s ⋅ 3 ⋅ R s



5.6 R')!$'( C+)+*!%, I,#)*"

T' %++%!, !"  ")--$ % *' $')!$'( !,#)*" *% *' +)+*!%, *% "*!" *!"  #$%'()$' 1> C%,*$* $%),(!, $')!$'-',*" % -'(!)-:=%+*' ,( +%:=%+*' )9!+!$ ""*'-. 2> U,!* )9!+!$8 "*$*)# ,( +%( ',*'$ *$,"%$-'$ %,,'*!%,". 3> C#!*,' *% $%),( %$ • ','$*%$  • S)$' $$'"*'$ • ','$*%$ "*'#:)# ,( ),!* )9!+!$ *$,"%$-'$" • I"%+*'( P"' B)" D)* 5. R')!$'( C+)+*!%, O)*#)*"

T' %++%!, !"  ")--$ % *' $')!$'( %)*#)*" *% *' +)+*!%, #$%=!('(  *!"  #$%'()$' 1> ','$*%$ N')*$+ $%),(!, C+)+*!%, ,( E)!#-',* R*!,. 2> M'(!)-:;%+*' N')*$+ $%),(!, E)!#-',* R*!,.

6.0 REFERENCES 6.1

EPRI P%'$ P+,* E+'*$!+ R''$',' S'$!'"8 ;%+)-' K8 S**!%, P$%*'*!%,.

.0 ATTAC!MENTS .1 .2

S-#+' P$%@'* C+)+*!%,: ','$*%$ ,( T$,"%$-'$ $%),(!, E)!#-',* R*!," <#(> S-#+' P$%@'* C+)+*!%,: N')*$+ $%),(!, T$,"%$-'$ ,( R'"!"*%$ S!!, C+)+*!%,: 4 ; A)9!+!$ (!"*$!)*!%, S"*'- <!#>