Earthing Trafo and NGR Calculation

Siemens Ltd., Kolkata

Simplex Engg. & Foundry Works (P) Ltd. R!L " #SP P$ System %or F " ' &  Earting *rans%ormer & !+R seletion and details

11.02.2009

132 KV, 31.5 KA Sym

 Y

132 / 11 KV 56.25 MVA 12.50%

Ear!"#g $rafo.

e&ral 'ro&#("#g   )es"sor  6.6 KV SoureVolage* +a&l leel*

132 KV 7201.656 MVA

ain *rans%ormer Pr"mary olage*

V1

132 KV

Se-o#(ary Volage* aa-"y* me(a#-e*

V2

11 KV 56.25 MVA 0.125 .&.

 

Earting *rans%ormerVE$1

11 KV

o

100 A 30 se-

 Arox"mae al&e of e&ral gro&#("#g res"sor > V2 x 1000 / 1.732 x o

)'a

63.5 63.510 108 8 !ms !ms

o#s"(ere( al&e of e&ral 'ro&#("#g )es"sor

)'

Pr"mary olage* 4"#e  4"#e Eart Fault $urrent4"m""#g al&e* &ra"o#* $alulation-

:ase MVA :ase olage :ase res"sa#-e > :ase KV2 / :ase MVA

50 !  !m s 56.25 MVA 11 KV 2.15 2.151 11 !ms !ms

So&r-e me(a#-e  > :ase MVA / So&r-e fa&l leel

?S

0.007; 0.007;1070 107035 35 .&. .&.

$oal So&r-e < $rafo me(a#-e

?$

0.132;107035 .&.

$oal So&r-e < $rafo me(a#-e "# !ms

?$

0.2;57 !  !ms

$oal So&r-e < $rafo me(a#-e  Pos""e se=&e#-e

?$1

0.2;57 !ms

$oal So&r-e < $rafo me(a#-e  ege"e se=&e#-e

?$2

0.2;57 !ms

+a&l leel o# 11 KV s"(e > :ase MVA / ?$

823.5 823.58 8 MVA MVA

Ma"# $rafo se-o#(ary P!ase Volage "# Vols*

V2P!

Ear!"#g $rafo s!or "me ra"#g  > @3 x V2P! x o/3

 E$

6351.08 Vo Vols 635 635 KVA KVA

Volage e=&a"o# of ear! fa&l e=&"ale# -"r-&" V2P! > o x )' < o / 3 x ? $1 < ?$2 < ?E$o Ear!"#g $rafo Bero se=&e#-e me(a#-e "# !ms* > 3 x @V2P! / o  )'  ?$1  ?$2

261353763.xls

?E$o

39.9 39.959 59; ; !ms !ms

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Siemens Ltd., Kolkata

Simplex Engg. & Foundry Works (P) Ltd. R!L " #SP P$ System %or F " ' &  Earting *rans%ormer & !+R seletion and details

Ear!"#g $rafo Bero se=&e#-e me(a#-e "# .&.* > ?E$o "# !ms x  E$/V22

?E$o

?E$o / ?$1

11.02.2009

0.2097 .&. 139.;7

Spei%iation o% Earting *rans%ormer)efere#-e sa#(ar( Max"m&m amC"e# emera&re )ae( 4"#e Volage D"g!es Sysem Volage +a&l leel o# l"#e s"(e o. of !ases ero se=&e#-e me(a#-e "# !ms ero se=&e#-e me(a#-e "# .&. $olera#-e o# Bero se=&e#-e me(a#-e Ve-or 'ro& +a&l &rre# !ro&g! e&ral S!or "me ra"#g of "#("#gs f ') "s s!ore( S!or "me KVA ra"#g #s&la"o# leel  m&lse #s&la"o# leel  Poer fre=&e#-y ool"#g #s&la"o# "#("#g maer"al $emera&re of "#("#g afer 100 A for 30 se$emera&re of "#("#g afer 159 A for 5 se-

S 2026 50 (eg.  11 KV 7.2 KV 823.58 MVA 3 39.959; !ms / !ase 0.2097 .&. 0%, <20% #0 100 A for 30 se-. 15;.98 A for 5 se-. 635 KVA for 30 se-. 75 KV 2; KV A lass  A oer   As er S 2026 As er S 2026

#-om"#g erm"#a"o# s&"aCle for 13/, 150 S=.mm Al ea-!aCle aCle Cox ?4PE -aCle e&ral :&s!"#g 11KV, 500 A m"#"m&m 1 o. +""#gs* 2 #os. Ear!"#g erm"#al Exlos"o# e# 4"f"#g !ooFs o&Cle floa :&-!!olB relay "! alarm a#( r" -o#a-s G#(er Case -!a##el "! C"("re-"o#al rollers Mars!all"#g Cox $!ermomeer o-Fe o#seraor "! "#(o ye o"l leel ga&ge S"l"-a 'el Crea!er  ra"# a#( f"ler ales Ha-F"#g a(s :&s!"#g ye 4"#e s"(e $* 3 #os. 100/1 A, -lass 5P20, 10 VA o#e for ea-! !ase e&ral $* 1 #o. 200/1 A, -lass 5P20, 10 VA

261353763.xls

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