summer internship report on wbsedcl substation

8/16/2019 Summer Internship Report on WBSEDCL Substation

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VOCATIONAL TRAINING REPORT

Under the Guidance of

Mr. K. Singh

.E. ! i"i#iona$ Manager

U$u%eria i"i#ion

&'SECL

Mr. A. Chatter(ee

!

Mr. R. Aha))ed

A##i#tant Engineer

Su%)itted %*

Arna% 'hui*a

'.Tech

+rd *ear

E$ectrica$ Engineering

Co$$ege of Engineering ! Manage)ent, Ko$aghat


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Table of Contents

Preface of the Project Report...................................................................................... 4

ACKNOWLEDGEMENT................................................................................................. 5

Rough decr!pt!o" o" #$u%er!a D!&!!o"......................................................................'

(u%)tat!o" Na*e a"d Load Capac!t+......................................................................,

(u%)tat!o"................................................................................................................. -

De"!t!o" of (u%)tat!o"/.......................................................................................-

(!te e$ect!o" for 00122K3 u%)tat!o".....................................................................-

Eu!p*e"t !" a 00122K3 u%tat!o"/...................................................................26

7u %ar/.............................................................................................................. 26

8o$ator/..............................................................................................................26

C!rcu!t %rea9er/................................................................................................... 22

Tra"for*er/....................................................................................................... 20

Protect!&e Re$a+/.................................................................................................2,

8"u$ator/............................................................................................................ :6

Co"ductor pec!cat!o"/.....................................................................................:2

Ca%$e/................................................................................................................. :2

L!ghte"!"g arretor/............................................................................................::

(u%tat!o" Earth!"g (+te*/................................................................................. ::

Earth *at/..........................................................................................................::

O"erhead ground -ire#............................................................................................:0

7u Coup$er/.......................................................................................................... :0

D.C. %atter+ ource/.............................................................................................. :0

Co"tro$ a"d Re$a+ Pa"e$/....................................................................................... :4

Tra"for*er protect!o"/............................................................................................:5

7uchho$; re$a+/......................................................................................................:5PR3/....................................................................................................................... :5

MOG/..................................................................................................................... :5

O(R/......................................................................................................................:5

D!


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Ma!"te"a"ce of u%)tat!o" eu!p*e"t/.................................................................:=

Pred!ct!&e *a!"te"a"ce/........................................................................................:=

Co"d!t!o" %aed *o"!tor!"g/.............................................................................. :,

Precaut!o"ar+ *a!"te"a"ce/..................................................................................:-

Co"c$u!o"/............................................................................................................... 06

7!%$!ograph+/............................................................................................................ 02


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Preface of the Project Report

I ha"e e/0erienced 1Vocationa$ Training2 in &'SECL U$u%eria i"i#ion fro) 34th 5une 6738

to +7th 5une 6738.

I a) "er* than9fu$ to a$$ the officer# for their 0reciou# ti)e for )e. &e ha"e e$ectrica$ 0o-er

#*#te) $a%, )achine $a% in our co$$ege -here -e ha"e %een trained in educationa$ en"iron)ent.

:o-e"er, %* thi# "ocationa$ training I ha"e $earnt )an* thing# in rea$ $ife en"iron)ent, -hich

-i$$ %e he$0fu$ for )* future. '* the 0ractica$ 9no-$edge, a00$ication and higher rated )achine

;tran#for)er ;37 MVA, 4.+ MVA, 377 KVA


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ACKNOWLEDGEMENTI -ou$d $i9e to e/0re## )* #incere gratitude to a$$ the 0eo0$e -ho had %een a##ociated -ith )e in

#o)e -a* or the other and he$0ed )e a"ai$ thi# o00ortunit* for )* Vocationa$ Training on the

to0ic

I a) e#0ecia$$* than9fu$ to Mr. K. Singh .M. of U$u%eria i"i#ion for 0ro"iding )e e/ce$$ent

guidance and )oti"ation.

I -ou$d $i9e to than9 Mr. Ari(it Chatter(ee ! Ra>ui% Aha)ed, A##i#tant Engineer U$u%eria

i"i#ion for their #u00ort and guidance throughout the "ocationa$ training.

I a) a$#o than9fu$ to the other officer# for #haring their "a$ua%$e e/0erience# at the *ard -ith the

0ractica$ 0heno)enon.


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Rough description on !u"eria Di#ision

U$u%eria i"i#ion i# a di"i#ion of the :o-rah i#trict in &e#t 'enga$. It con#i#t# of U$u%eria

Munici0a$it* and #e"en CCC %$oc9#.

3. 'uri9ha$i CCC

6. 'i#h%0ur CCC+. 'agnan?I CCC

@. 'agnan?II CCC

8. A(odh*a CCC4. Panch$a CCC

. Garchu)u9 CCC

The #e"en %$oc9# contain B7 Gra)?Pancha*t# and #i/ cen#u# to-n#. The di"i#ion ha# it#

head>uarter# at U$u%eria.

U$u%eria i"i#ion ha# e$e"en ++33 KV #u%#tation#

3. 'anita%$a Su%?#tation

6. 'agnan Su%?#tation

+. U$u%eria Indu#tria$ Gro-th Centre Su%?#tation@. U$%eria Grid Su%?#tation

8. Dood Par9 Su%?#tation

4. Po$* 0ar9 Su%?#tation. Doundr* Par9 Su%?#tation


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. Mug?9a$*an0ur Su%?#tation

B. Sh*a)0ur Su%?#tation

37. 'aganda Su%?#tation33. Ranihati Su%?#tation

36. Ka$*an0ur Su%?#tation


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$u"%station Na&e and Load Capacit'

$u"%station

Sub-station Name Installed Capacity

MVA

'anita%$a Su%?#tation +F4.+

Ranihati Su%?#tation +F4.+

Dood 0ar9 Su%?#tation +F37

Po$* 0ar9 Su%?#tation +F37

Doundr* 0ar9 Su%?#tation 3F37, 3F4.+

U$%eria Indu#tria$ Gro-th centre Su%?#tation 3F37, 6F4.+

U$u%eria Grid Su%?#tation +F4.+

'agnan Su%?#tation +F4.+

Ka$*an0ur Su%?#tation 6F4.+

'aganda Su%?#tation 6F4.+

Mug9a$*an Su%?#tation 6F4.+

Sh*a)0ur Su%?#tation 6F4.+


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De(nition of $u"%stations)

The a##e)%$* of a00aratu# u#ed to change #o)e characteri#tic# ;e.g. "o$tage #te0 u0 to #te0 do-n

or "ice "er#a< of e$ectric #u00$* #*#te) i# 9no-n a# #u%?#tation.

The e$ectric 0o-er i# 0roduced at generating #tation#. It i# de$i"ered to the con#u)er end#

through a $arge net-or9 of tran#)i##ion and di#tri%ution. At )an* 0$ace in the $ine of #u00$*

#*#te), it )a* %e de#ira%$e to and nece##ar* to change #o)e characteri#tic# ;e.g. "o$tage #te0 u0

to #te0 do-n or "ice "er#a< of e$ectric #u00$* #*#te). Thi# i# acco)0$i#hed %* #uita%$e a00aratu#

ca$$ed #u%?#tation.

Dor e/a)0$e, generation "o$tage 33 KV at the generation #tation i# #te00ed high to 3+6KV or

667KV for tran#)i##ion and #te00ed do-n to ++ KV and further #te00ed do-n to 33KV for

di#tri%ution.

$ite se!ection for **+,,K- su"%station

Main 0oint# to %e con#idered -hi$e #e$ecting the #ite for Su%?Station are a# fo$$o-#

i< The #ite cho#en #hou$d %e a# near to the $oad center a# 0o##i%$e.ii< It #hou$d %e ea#i$* a00roacha%$e %* road or rai$ for tran#0ortation of e>ui0)ent#.

iii< Land #hou$d %e fair$* $e"e$ed to )ini)i=e de"e$o0)ent co#t.

i"< The #ource of -ater #hou$d %e a# near to the #ite a# 0o##i%$e. Thi# i# %ecau#e -ater i#

re>uired for "ariou# con#truction acti"itie# H; E#0ecia$$* ci"i$ -or9#,


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E.uip&ent/s in a **+,,K- su"station)

0us "ar)

&hen no of feeder# are o0erating at the #a)e "o$tage ha"e to %e direct$* connected e$ectrica$$*,

%u# %ar i# u#ed a# the co))on e$ectrica$ e>ui0)ent. 'u# %ar# are )ade of 0anther ca%$e to

o0erate at con#tant "o$tage. In #u%?#tation it i# i)0ortant to %rea9 do-n and )aintenance #hou$d %e interfere a# $itt$e a# 0o##i%$e -ith continuit* of #u00$*, to achie"e thi# high %u# and $o- %u#

#*#te) are u#ed.

1so!ator)

I#o$ator i# a )echanica$ #-itch -hich i#o$ate# a 0art of circuit fro) re#t of the #*#te). Circuit

%rea9er a$-a*# tri0# the circuit %ut o0en contact# of %rea9er cannot %e "i#i%$e 0h*#ica$$* fro)

out#ide of the %rea9er. So for %etter #afet* there )u#t %e #o)e arrange)ent #o that one can #ee

the o0en condition of the #ection of the circuit %efore touching it. There are different t*0e# of

i#o$ator# a"ai$a%$e de0ending u0on #*#te) re>uire)ent #uch a#

3. T.P.G.O.6. C.R.T.


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Circuit "rea2er)

E$ectrica$ circuit %rea9er i# a #-itching de"ice -hich can %e o0erated )anua$$* a# -e$$ a#

auto)atica$$* for contro$$ing and 0rotection of e$ectrica$ 0o-er #*#te) re#0ecti"e$*. Genera$$*

Vacuu) circuit %rea9er# are u#ed in ++33KV #u%?#tation.

Vacuum circuit breaker:A "acuu) circuit %rea9er i# #uch 9ind of circuit %rea9er -here the arc >uenching ta9e# 0$ace in

"acuu). The o0eration of o0ening and c$o#ing of current carr*ing contact# and a##ociated arc

interru0tion ta9e 0$ace in a "acuu) cha)%er in the %rea9er -hich i# ca$$ed "acuu) interru0ter.

The "acuu) interru0ter con#i#t# of a #tee$ arc cha)%er in the center #*))etrica$$* arranged

cera)ic in#u$ator#. The "acuu) 0re##ure in#ide a "acuu) interru0ter i# nor)a$$* )aintained at

37 ? 4 %ar.

Advantages of Vacuum Circuit Breakers

3. Vacuu) circuit %rea9er# doe# not re>uire fi$$ing of an* ga# or oi$. The* do not need

au/i$iar* air #*#te), oi$ hand$ing and free fro) 0eriodic )aintenance

6. Ra0id reco"er* of "er* high die$ectric #trength on current interru0tion #o that on$* ha$f

c*c$e or $e## arcing occur# after 0ro0er contact #e0eration

+. No e)i##ion of ga#e#, hence 0o$$ution free

@. Current interru0tion occur# at fir#t current =ero after contact #e0aration -ith no re?

#tri9ing, )a9ing it e/ce0tiona$$* good for ca0acitor and ca%$e #-itching and $ong $ine

droo0ing8. Non e/0$o#i"e and #i$ent o0eration co)0ared to air %$a#t and SD4 %rea9er#.

isadvantages of Vacuum Circuit Breakers

3. Vacuu) circuit %rea9er# are unecono)ica$ a%o"e +4KV and SD4 %rea9er# ha"ing

e>ui"a$ent 0ro0ertie# are econo)ica$. :ence for E:V ;"o$tage# a%o"e 6+7KV < #*#te)#

SD4 circuit %rea9er# are e)0$o*ed6. Lo## of "acuu) due to tran#it da)age or fai$ure )a9e# the entire interru0tion u#e$e## and

it cannot %e re0aired at #ite.


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Specification of !!"V Vacuum Circuit Breaker#

T*0e +4KV, 68KA

Vo$tage +4KV

Current 3687A

Dre>uenc* 87:=

No. of 0o$e# +

'rea9ing current +3.89A)0#

Ma9er# Rated Current 79A)0#

Short Circuit -ith#tand current ! duration +3.89A)0# for +#ec#

.C. Co)0onent 87J

'IL 737KV0

Shunt Tri0 6+7 V ;d.c.<

Ma## B779g

Ma9er A''

Transfor&er)

In #u%?#tation# t-o t*0e# of tran#for)er are u#ed.


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A. Po-er tran#for)er ;++KV33KV<

'. Station tran#for)er ;++KV.@@KV<

C. In#tru)ent tran#for)er

Power transformer:

Tran#for)er i# a #tatic de"ice %* )ean# of -hich e$ectric 0o-er in one circuit i# tran#for)ed intoe$ectric 0o-er of the #a)e fre>uenc* in another circuit. The 0h*#ica$ %a#i# of a tran#for)er i#

)utua$ induction %et-een t-o circuit# $in9ed %* a co))on )agnetic f$u/. It con#i#t# of t-o

inducti"e coi$# -hich are e$ectrica$$* #e0arated %ut )agnetica$$* $in9ed through a 0ath of $o-

re$uctance. The fir#t coi$ in -hich e$ectrica$ energ* i# fed fro) the a.c. #u00$* )ain#, i# ca$$ed

0ri)ar* -inding and the other fro) -hich energ* i# dra-n out, i# ca$$ed #econdar* -inding.

A# the #*#te) "o$tage goe# u0, the techni>ue# to %e u#ed for the de#ign, con#truction,

in#ta$$ation, o0eration# and )aintenance a$#o %eco)e )ore and )ore critica$. The tran#for)er#

u#ed in #u%?#tation# ha# de$ta #tar ;< connection.

Accessories of transformer#

Core $ %inding#


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There are t-o genera$ t*0e# of tran#for)er#, the core t*0e and the #he$$ t*0e. The )agnetic core

i# a #tac9 of thin #i$icon?#tee$ $a)ination#. In order to reduce the edd* current $o##e# the#e

$a)ination# are in#u$ated fro) one another %* thin $a*er# of "arni#h. Dor reducing the core

$o##e#, the )agnetic core )ade fro) co$d?ro$$ed grain?oriented #heet #tee$ ;C.R.G.O.uate #0ace to thi# e/0and tran#for)er oi$

and it a$#o act# a# a re#er"oir for tran#for)er oi$.

Breat&er#

&hene"er tran#for)er i# $oaded, the te)0erature of the

tran#for)er oi$ increa#e#, con#e>uent$* the "o$u)e of the

oi$ i# increa#ed and the air a%o"e the oi$ $e"e$ incon#er"ator -i$$ co)e out. &hen the oi$ te)0erature i# $o-,

the "o$u)e of the oi$ i# decrea#ed -hich cau#e# air to enter into the con#er"ator. The out#ide air

a$-a*# contain# )oi#ture -hich i# "er* har)fu$ for tran#for)er in#u$ation. A #i$ica ge$ %reather

i# u#ed for fi$tering air fro) )oi#ture. Si$ica ge$ %reather i# connected -ith con#er"ator tan9 %*

)ean# of %reathing 0i0e. To re)o"e the du#t 0artic$e a 0ot i# attached -ith %reather end.

'adiator#


15/32

Under $oaded condition, heat i# 0roduced in the -inding -hich in

turn increa#e the te)0erature of the oi$. The -ar) oi$ increa#e# in

"o$u)e and co)e# to the u00er 0ortion of the )ain tan9. Then

thi# oi$ enter# in the radiator through to0 "a$"e and coo$# do-n %*

di##i0ating heat through the thin radiator -a$$. Thi# co$d oi$

co)e# %ac9 to the )ain tan9 through the %otto) radiator "a$"e.

Bus&ing#

It i# fi/ed on the tran#for)er tan9 and the#e connection# are )ade

to the e/terna$ circuit#. Ordinar* 0orce$ain in#u$ator# can %e u#ed

a# %u#hing u0 to "o$tage of ++KV.

Mars&aling Bo(#

It ha# t-o )eter -hich indicate# the te)0erature of the oi$ and

-inding if the )ain tan9. If te)0erature of oi$ or -inding e/ceed#

than #0ecified "a$ue, re$a* o0erate# to #ound a$ar). If there i#

further increa#e in te)0erature than re$a* co)0$ete# the tri0

circuit %rea9er contro$$ing the tran#for)er.

)'V#

PRV ;Pre##ure re$ief "a$"e< i# one of the 0rotection co)0onent#

in the tran#for)er. It i# u#ed to )aintain in#ide 0re##ure for the

#afet* 0ur0o#e. It# -or9# auto)atica$$* -hen in#ide 0re##ure

i# out of $i)it#.

Arcing &orn#

It con#i#t# of t-o horn #ha0ed )eta$ rod# #e0arated %* a #)a$$ air ga0. The horn# are )ounted on

the 0orce$ain in#u$ator#. On the occurrence of high "o$tage, arcing ta9e# 0$ace acro## the ga0 !

the arc tra"e$ u0 the ga0. Con#e>uent$* the arc i# e/tingui#hed ! the e/ce## charge on the $ine i#

conducted to ground.

Buc&&ol* relay#


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It i# a ga# actuated re$a* in#ta$$ed in oi$ i))er#ed tran#for)er# ha"ing rating )ore than 877KVa

for 0rotection again#t a$$ 9ind# of interna$ fau$t#. Such re$a*# can on$* %e fitted to the

tran#for)er# e>ui00ed -ith con#er"ator tan9# a# it i# in#ta$$ed in %et-een the con#er"ator tan9

and tran#for)er tan9.

It con#i#t# of t-o hinged f$oat. The to0 f$oat i# connected -ith a$ar) circuit and the $o-er f$oat

i# connected -ith the tri0 circuit. &hene"er a fau$t occur# in#ide the tran#for)er the oi$ of the

tan9 get# o"erheated and ga#e# are generated and co$$ected in the cha)%er #o the oi$ $e"e$

gradua$$* fa$$# ! c$o#ing the a$ar) circuit. I f no attention i# 0aid to it, the ga# co$$ection -i$$ %e

)ore ! c$o#e# another circuit -hich -i$$ cut out the tran#for)er fro) the $ine.

+,TC#

In 0o-er tran#for)er, for 0ro0er "o$tage regu$ation of tran#for)er , on $oad ta0 changer i#

re>uired. A# there i# no 0er)i##ion of #-itching off the tran#for)er during ta0 changing. The

ta00ing arrange)ent i# 0$aced in #e0arate di"erter tan9 attached to e$ectrica$ 0o-er tran#for)er

)ain tan9. In#ide thi# tan9, the ta0 #e$ector# are genera$$* arranged in a circu$ar for). The

di"erter #-itche# ha"e contact# o0erating in ra0id #e>uence -ith u#ua$$* four #e0arate )a9e and

%rea9 unit#.

of .V Turns Tap S%itc&)osition

Connections .V Side Volts ,V Side Volts

8 3 to 4 +@487 33777

6.8 6 4 to ++68 33777

N + to 8 ++777 33777

?6.8 @ 8 to B +638 33777

?8 8 B to @ +3+87 33777

?.8 + @ to 37 +7868 33777

?37 37 to + 6B77 33777

Specification of transformer#

http://www.electrical4u.com/voltage-regulation-of-transformer/http://www.electrical4u.com/voltage-regulation-of-transformer/


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MVA rating 4.+ 37

Vo$tage at no $oad :V #ide LV

#ide

++KV33KV ++KV33KV

Current at :V #ide LV #ide 337.68A++7.44A 38A868A

I)0edance "o$tage J .8B

Dre>uenc* 87:= 87:=

T*0e of coo$ing ONAN ONAN

Vector grou0 *n?33 *n?33

Ma## of oi$

Tota$ )a##

Vo$u)e of oi$

Ma/i)u) te)0erature ri#e in

oi$

87> 87>

Station transformer:

E"er* #u%?#tation ha# one #tation tran#for)er. The #tation tran#for)er i# a ++KV@@7"o$t

tran#for)er. It )aintain# the continuou# 0o-er #u00$* of #u%?#tation.


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Instrument transformer:

I. Current transformer/

Current tran#for)er# are %a#ica$$* u#ed to ta9e the reading# of the current# entering the

#u%#tation. Thi# tran#for)er #te0# do-n the current fro) @77 a)0# to 3 a)0. Thi# i# done

%ecau#e -e ha"e no in#tru)ent for )ea#uring of #uch a $arge current. The )ain u#e of thi#

tran#for)er i#

• i#tance Protection

• 'ac9u0 Protection

• Mea#ure)ent

II. )otential transformer#

There are t-o 0otentia$ tran#for)er# u#ed in the %u# connected %oth #ide of the %u#. The 0otentia$

tran#for)er u#e# a %u# i#o$ator to 0rotect it#e$f. The )ain u#e of thi# tran#for)er i# to )ea#ure

the "o$tage through the %u#. Thi# i# done #o a# to get the detai$ infor)ation of the "o$tage 0a##ing

through the %u# to the in#tru)ent. There are t-o )ain 0art# in it

• Mea#ure)ent

• Protection

Protecti#e Re!a')

A 0rotecti"e re$a* i# a de"ice that detect# the fau$t and initiate# the o0eration of the C.'. i# to

i#o$ate the defecti"e e$e)ent fro) the re#t of the #*#te). The re$a* detect# the a%nor)a$

condition in the e$ectrica$ circuit %* con#tant$* )ea#uring the e$ectrica$ >uantitie#, -hich are

different under nor)a$ and fau$t condition.

Mo#t of the re$a* o0erate# on the 0rinci0$e of e$ectro)agnetic attraction or e$ectro)agnetic

induction. The fo$$o-ing i)0ortant t*0e# of re$a*# are u#ed in ++33KV #u%?#tation#.


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3. Induction t*0e o"er current re$a*

6. ifferentia$ Re$a*

+. Earth fau$t re$a*@. Re#tricted earth fau$t re$a*

8. Ma#ter tri0 re$a*

Instantaneous type over current relay:

The o"er current re$a* re#0ond# to a )agnitude of

current a%o"e a #0ecified "a$ue. There are four %a#ic

t*0e# of con#truction The* are 0$unger, rotating di#c,

#tatic, and )icro0roce##or t*0e. In the 0$unger t*0e, a

0$unger i# )o"ed %* )agnetic attraction -hen the

current e/ceed# a #0ecified "a$ue. In the rotating

induction?di#c t*0e, -hich i# a )otor, the di#c rotate#

%* e$ectro)agnetic induction -hen the current e/ceed#

a #0ecified "a$ue.

Restricted earth fault relay:

An e/terna$ fau$t in the #tar #ide -i$$ re#u$t in current f$o-ing in the $ine current tran#for)er of

the affected 0ha#e and at the #a)e ti)e a %a$ancing current f$o-# in the neutra$ current

tran#for)er, hence the re#u$tant current in the re$a* i# therefore =ero. So thi# RED re$a* -i$$ not

%e actuated for e/terna$ earth fau$t. 'ut during interna$ fau$t the neutra$ current tran#for)er on$*

carrie# the un%a$ance fau$t current and o0eration of Re#tricted Earth Dau$t Re$a* ta9e# 0$ace. Thi#

#che)e of re#tricted earth fau$t 0rotection i# "er* #en#iti"e for interna$ earth fau$t of tran#for)er.

The 0rotection #che)e i# co)0arati"e$* chea0er than differentia$ 0rotection #che)e.

)rotection Sc&eme


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Master trip relay:

Ma#ter tri0 re$a* 4 i# the )ain tri0 re$a*. The %rea9er -i$$ tri0

through thi# re$a* on$*. In tran#)i##ion ! di#tri%ution $ine

there are #o )an* 0rotection re$a*# $i9e o"ercurrent re$a*, earth

fau$t re$a*. A$$ re$a*# contact -i$$ connect 0ara$$e$ to )a#ter

tri0 re$a*. If an* of the 0rotection re$a* #en#e the fau$t. It -i$$

energi=e the )a#ter tri0 re$* and the )a#ter tri0 re$a* -i$$ tri0

the %rea9er. It got one )ore na)e $i9e $oc9 out re$a*.

1nsu!ator)

There are )ain$* three t*0e# of in#u$ator u#ed in #u%?#tation.

3. Pin In#u$ator 6. Su#0en#ion In#u$ator

+. Po#t In#u$ator

Pin type insulator:

A# the na)e #ugge#t#, the 0in t*0e in#u$ator i# )ounted on a 0in on the cro##?ar) on the 0o$e.

There i# a groo"e on the u00er end of the in#u$ator. The conductor 0a##e# through thi# groo"e

and i# tied to the in#u$ator -ith annea$ed -ire of the #a)e )ateria$ a# the conductor. Pin t*0ein#u$ator# are u#ed for tran#)i##ion and di#tri%ution of co))unication#, and e$ectric 0o-er at

"o$tage# u0 to ++ KV. 'e*ond o0erating "o$tage of ++ KV, the 0in t*0e in#u$ator# %eco)e too

%u$9* and hence unecono)ica$.


21/32

Suspension insulator:

Dor "o$tage# greater than ++ KV, it i# a u#ua$ 0ractice to u#e #u#0en#ion t*0e in#u$ator#,

con#i#ting of a nu)%er of g$a## or 0orce$ain di#c# connected in #erie# %* )eta$ $in9# in the for)

of a #tring. The conductor i# #u#0ended at the %otto) end of thi# #tring -hi$e the to0 end i#

#ecured to the cro##?ar) of the to-er. The nu)%er of di#c unit# u#ed de0end# on the "o$tage.

Post Insulator:

Po#t in#u$ator i# )ore or $e## #i)i$ar to Pin in#u$ator %ut for)er i# #uita%$e for higher "o$tage

a00$ication. Po#t in#u$ator ha# higher nu)%er# of 0etticoat# and ha# greater height. Thi# t*0e of

in#u$ator can %e )ounted on #u00orting #tructure hori=onta$$* a# -e$$ a# "ertica$$*. The in#u$ator

i# )ade of one 0iece of 0orce$ain %ut ha# fi/ing c$a)0 arrange)ent are in %oth to0 and %otto)

end.

Conductor speci(cation)

Conductor na)e Area

;))<

Current carr*ing

ca0acit*

;A)0<

A00$ication

og 377 647 :igh current

tran#)i##ion 0ur0o#e#

Panther 677 847 'u#

Ca"!e)

Cro##?$in9ed 0o$*eth*$ene, co))on$* a%%re"iated PEF or FLPE, i# a for)

of 0o$*eth*$ene -ith cro##?$in9#.


22/32

)articular ata ata

Rated "o$tage ++KV 33KV

:ighe#t #*#te) "o$tage +4KV 36KV

Short circuit current 3< @.3 KA for 3Sec for ++

KV 877

#>.))6< +.4 KA for 3Sec for ++

KV @77

#>.))

3< @.7 KA;B8.@MVA< for 3

#ec for 33KV 877 #>.))

6< +.4 KA ;34.+MVA< for 3 #ec for

33 KV @77 #>.))

Ma/i)u). Per)i##i%$e #hort

circuit Te)0erature

687deg for 3 #ec 687deg for 3 #ec

Continuou# -ith#tand current B7deg B7deg

Materia$ of conductor A$u)inu) A$u)inu)

In#u$ation FLPE of thic9ne##, .

;Mini)u)< for ++ KV

FLPE of thic9ne##, +.4 )).

;No)ina$< for 33 KV

Lightening arrestor)

A $ightning arre#ter i# a de"ice u#ed on e$ectrica$ #*#te)# to 0rotect the e>ui0)ent# and

conductor# of the #*#te) fro) the effect# of $ightening. The $ightening arre#tor can -or9 in an

ang$e of @8degree# around the). Meta$ o/ide

arre#tor# are u#ed for $ightening 0ur0o#e. Innor)a$ ca#e, it %eha"e# $i9e a high re#i#tance

0ath %ut -hen $ightening occur# it %eha"e# $i9e

a $o- re#i#tance 0ath. &hen $ightening #urge

0a##e# through thi# the #urge i# di"erted

through the arre#tor to earth. The LA#

e)0$o*ed for 0rotecting tran#for)er# #hou$d

%e in#ta$$ed a# c$o#e

a# 0o##i%$e to the tran#for)er.

$u"station Earthing $'ste&)

Earth &at)

In #u%#tation an earth )at i# in#ta$$ed at 0$ace# -here a 0er#on or an o0erator -ou$d #tand to

o0erate a #-itch or a00aratu#. In the "icinit* of e$ectro#tatic #en#iti"e de"ice#, an earth )at i#

u#ed to ground the #tatic e$ectricit* generated %* e>ui0)ent#.


23/32

+ver&ead ground %ires#

The )o#t effecti"e )ethod of 0ro"iding 0rotection

again#t direct $ightning #tro9e# i# %* the u#e of o"erhead

ground -ire#. The ground -ire# are 0$aced o"er the $ine

conductor# at #uch 0o#ition that 0ractica$$* a$$ $ightning

#tro9e# are interce0ted %* the). The ground -ire i#

ground at each to-er through a# $o- re#i#tance a#

0o##i%$e. &hen the direct $ightning #tro9e# occur on the

$ine -i$$ %e ta9en %* the ground -ire. The hea"* current#

f$o- to the ground through thi# -ire.

0us Coup!er)

The %u# cou0$er con#i#t# of circuit %rea9er and i#o$ator. Each feeder )a* %e connected to either

)ain %u# %ar or #0ar %u# %ar -ith the he$0 of %u# cou0$er. Re0airing, )aintenance and te#ting offeeder #ection can %e done %* 0utting the) on #0ar %u# %ar, thu# 9ee0ing the )ain %u# %ar

undi#tur%ed. 'u# cou0$er i# a de"ice -hich i# u#ed to #-itch fro) one %u# to another %u# -ithout

an* interru0tion in 0o-er #u00$* and -ithout creating ha=ardou# arc#.

D3C3 "atter' source)

The o0eration of )onitoring de"ice# #uch a# re$a*# and the tri00ing )echani#) of %rea9er#

re>uire an inde0endent 0o-er #ource,

-hich doe# not "ar* -ith )ain #ource %eing )onitored. 'atterie# 0ro"ide thi#

0o-er #ource for the #ucce##fu$ o0eration

of #-itching and contro$ the de"ice in

#u%?#tation. Each %atter* i# con#idered

6.6 "o$t and 34 %atterie# are re>uired to

contro$ the 0ane$.


24/32

Contro! and Re!a' Pane!)

The contro$ and re$a* 0ane$ i# of cu%ica$ con#truction #uita%$e for f$oor )ounting. A$$ 0rotecti"e,

indicating and contro$

e$e)ent# are )ounted on the

front 0ane$ for ea#e of

o0eration and contro$. The

hinged rear door -i$$

0ro"ide acce## to a$$ the

interna$ co)0onent# to

faci$itate ea#* in#0ection

and )aintenance. Pro"i#ion

i# )ade for ter)inating

inco)ing ca%$e# at the

%otto) of the 0ane$# %*

0ro"iding #e0arate $ine?u0

ter)ina$ %$oc9#. Dor ca%$eentr* 0ro"i#ion i# )ade %oth

fro) to0 and %otto). The

contro$ and re$a* 0ane$

acce0t# CT, PT au/ 6+7 AC and 667V37V C connection# at re#0ecti"e de#ignated ter)ina$

0oint#. 667V37V C #u00$* i# u#ed for contro$ #u00$* of a$$ interna$ re$a*# and ti)er# and a$#o

for energi=ing c$o#ing and tri00ing coi$# of the %rea9er#. 6+7V AC #tation au/i$iar* #u00$* i#

u#ed for interna$ i$$u)ination $a)0 of the 0ane$ and the #0ace heater. Protecti"e :RC fu#e are

0ro"ided -ith in the 0ane$. 'rea9er# are 0ro"ided -ith a $ine a))eter -ith #e$ector #-itch for +

0ha#e #*#te) ! o"er current re$a* ;6 0ha#e# and 3 Earth fau$t for + 0ha#e #*#te)


25/32

Transfor&er protection)

0uchho!4 re!a')

It i# a ga# actuated re$a* in#ta$$ed in oi$ i))er#ed tran#for)er# ha"ing rating )ore than 877KVa

for 0rotection again#t a$$ 9ind# of interna$ fau$t#. Such re$a*# can on$* %e fitted to the

tran#for)er# e>ui00ed -ith con#er"ator tan9# a# it i# in#ta$$ed in %et-een the con#er"ator tan9

and tran#for)er tan9.

It con#i#t# of t-o hinged f$oat. The to0 f$oat i# connected -ith a$ar) circuit and the $o-er f$oat i#

connected -ith the tri0 circuit. &hene"er a fau$t occur# in#ide the tran#for)er the oi$ of the tan9

get# o"erheated and ga#e# are generated and co$$ected in the cha)%er #o the oi$ $e"e$ gradua$$*

fa$$# ! c$o#ing the a$ar) circuit. I f no attention i# 0aid to it, the ga# co$$ection -i$$ %e )ore !

c$o#e# another circuit -hich -i$$ cut out the tran#for)er fro) the $ine.

PR-)

PRV ;Pre##ure re$ief "a$"e< i# one of the 0rotection co)0onent# in the tran#for)er. It i# u#ed to)aintain in#ide 0re##ure for the #afet* 0ur0o#e. It# -or9# auto)atica$$* -hen in#ide 0re##ure

i# out of $i)it#.

MOG)

Thi# de"ice i# u#ed to indicate the 0o#ition of tran#for)er in#u$ating oi$ $e"e$ in con#er"ator of

tran#for)er. A$$ oi$ i))er#ed di#tri%ution and e$ectrica$ 0o-er tran#for)er# are 0ro"ided -ith

e/0an#ion "e##e$ -hich i# 9no-n a# con#er"ator of tran#for)er. Thi# "e##e$ ta9e# care of oi$

e/0an#ion due to te)0erature ri#e. &hen tran#for)er in#u$ating oi$ i# e/0anded, the oi$ $e"e$ in

the con#er"ator tan9 goe# u0. Again -hen oi$ "o$u)e i# reduced due to fa$$ in oi$ te)0erature,

the oi$ $e"e$ in the con#er"ator goe# do-n. 'ut it i# e##entia$ to )aintain a )ini)u) oi$ $e"e$ inthe con#er"ator tan9 of tran#for)er e"en at $o-e#t 0o##i%$e te)0erature. A$$ $arge e$ectrica$

0o-er tran#for)er# are therefore 0ro"ided -ith a )agnetic oi$ $e"e$ indicator or )agnetic oi$

gauge/ Magnetic oi$ $e"e$ indicator i# a$#o incor0orated -ith a )ercur* #-itch. A# the a$ign)ent

of )ercur* #-itch change# a$ong -ith the 0ointer, thi# #-itch c$o#e# and actuate# an audi%$e

a$ar) -hen 0ointer reache# near e)0t* 0o#ition on the dia$ of )agnetic oi$ gauge.

O$R)

The Oi$ Surge Re$a* i# connected in %et-een OLTC cha)%er and con#er"ator tan9 -ith %reather.

A #e0aration #hou$d %e arranged #uch that the oi$ in OLTC cha)%er and tran#for)er )ain tan9

#hou$d not %e )i/ed together. In ca#e an* 0ro%$e) occur# during on $oad ta0 changing o0eration,

a ga# i# de"e$o0ed and that ga# -i$$ actuate the OSR. And the re$a* acti"ate# the a$ar) circuit.


26/32

Di5erentia! protection)

Genera$$* ifferentia$ 0rotection i# 0ro"ided in the tran#for)er rated )ore than 8MVA. The

ifferentia$ Protection of Tran#for)er ha# ad"antage# o"er other #che)e# of 0rotection.

The fau$t# occur in the tran#for)er in#ide the in#u$ating oi$ can %e detected %* 'uchho$= re$a*.'ut if an* fau$t occur# in the tran#for)er %ut not in oi$ then it cannot %e detected %* 'uchho$=

re$a*. An* f$a#h o"er at the %u#hing# are not ade>uate$* co"ered %* 'uchho$= re$a*. ifferentia$

re$a*# can detect #uch t*0e of fau$t#. Moreo"er 'uchho$= re$a* i# 0ro"ided in tran#for)er for

detecting an* interna$ fau$t in the tran#for)er %ut ifferentia$ Protection #che)e detect# the #a)e

in fa#ter -a*.

O#er current and Earth fau!t protection)

'ac9u0 0rotection of e$ectrica$ tran#for)er i# #i)0$e O"er Current and Earth Dau$t 0rotection

a00$ied again#t e/terna$ #hort circuit and e/ce##i"e o"er $oad#. The#e o"er current and earth

Dau$t re$a*# )a* %e of In"er#e efinite Mini)u) Ti)e ;IMT< or efinite Ti)e t*0e re$a*#.

Genera$$* IMT re$a*# are connected to the in?feed #ide of the tran#for)er.

The o"er current re$a*# cannot di#tingui#h %et-een e/terna$ #hort circuit, o"er $oad and interna$

fau$t# of the tran#for)er. Dor an* of the a%o"e fau$t, %ac9u0 0rotection i.e. o"er current and earth

fau$t 0rotection connected to in?feed #ide of the tran#for)er -i$$ o0erate. 'ac9u0 0rotection i#

a$though genera$$* in#ta$$ed


27/32

Restricted earth fau!t protection)

An e/terna$ fau$t in the #tar #ide -i$$ re#u$t in current f$o-ing in the $ine current tran#for)er of

the affected 0ha#e and at the #a)e ti)e a %a$ancing current f$o-# in the neutra$ current

tran#for)er, hence the re#u$tant current in the re$a* i# therefore =ero. So thi# RED re$a* -i$$ not

%e actuated for e/terna$ earth fau$t. 'ut during interna$ fau$t the neutra$ current tran#for)er on$*

carrie# the un%a$ance fau$t current and o0eration of Re#tricted Earth Dau$t Re$a* ta9e# 0$ace. Thi#

#che)e of re#tricted earth fau$t 0rotection i# "er* #en#iti"e for interna$ earth fau$t of tran#for)er.

The 0rotection #che)e i# co)0arati"e$* chea0er than differentia$ 0rotection #che)e.

Oi! and Winding Te&perature 1ndicator of Transfor&er)

The#e are genera$$* 0reci#ion in#tru)ent#. A te)0erature indicator of 0o-er tran#for)er i#

#0ecia$$* de#igned for 0rotection of tran#for)er in addition to it# te)0erature indication and

coo$ing contro$ feature#. That )ean#, thi# de"ice 0erfor)# three function#

3. The#e in#tru)ent# indicate in#tantaneou# te)0erature of oi$ and -inding# of tran#for)er.

6. Thi# a$#o record )a/i)u) te)0erature ri#e of oi$ and -inding#.+. The#e in#tru)ent# o0erate high te)0erature a$ar) at a 0redeter)ined "a$ue of a$$o-a%$e

te)0erature $i)it.@. Te)0erature indicator# of tran#for)er can a$#o tri0 the circuit %rea9er# a##ociated -ith

the 0o-er tran#for)er -hen the te)0erature of oi$ or -inding reache# a 0redeter)ined

$i)it.

&TI ! OTI #ha$$ %e #et to o0erate at the fo$$o-ing te)0erature

Oi$?A$ar)?7 >, Tri0?B7 >

&$nding?A$ar)?8>, Tri0?B8 >

Maintenance of su"%station e.uip&ent/s)

• Predicti"e Maintenance.

• Precautionar* Maintenance.

Predicti#e &aintenance)

Predicti"e )aintenance i# gaining 0o0u$arit* a# a 0roducti"it* too$ %ecau#e it he$0# e$i)inateun#chedu$ed do-nti)e of e/0en#i"e e>ui0)ent and reduce the o"era$$ co#t of )aintenance. Thi#

a00roach, #o)eti)e# ca$$ed condition?%a#ed )aintenance.

It ha# #o)e ad"antage#. The* are a# fo$$o-#,

0/ Reduced $ife c*c$e co#t# through $o-er )aintenance co#t#, reduced e/0enditure for #0are

0art#, and e/tended co)0onent $ife.

1/ Ma/i)i=ed co)0onent $ife through con#i#tent 0re"ention of condition# that reduce the

$ife e/0ectanc* of the e>ui0)ent.


28/32

!/ O0ti)i=ed 0erfor)ance through $oading a%o"e %oo9 rating.

2/ Mini)i=ed do-nti)e through 0roacti"e re0air 0$anning %a#ed on infor)ation gained

fro) a##et )onitoring.

3/ Reduction of in#urance co#t# %* de)on#trating re#0on#i%$e cu#todian#hi0 o"er grid

a##et#.

4/ A"oidance of 0ena$tie# through effecti"e 0rediction and 0re"ention of e>ui0)ent fai$ure#.5/ En"iron)enta$ %enefit# through 0re"ention of en"iron)enta$$* ha=ardou# condition#.

Condition "ased &onitoring)

IR thermometer for detecting hot spot:

The identification and the 0o##i%$e e$i)ination of :ot S0ot# in ti)e can #afeguard )an*

e>ui0)ent in a #u%?#tation. It he$0# to a"oid un#chedu$ed outage# and the con#e>uence )onetar*

$o##. Thu# %* 0rior detection of the hot #0ot#, the #u%?#tation i# #afeguarded and entire

re0$ace)ent of the 0$ant co)0onent# -i$$ %e )ade o%#o$ete. The i)0ortance of IR ca)era in

detecting :ot #0ot# in a high "o$tage #u%#tation i# -e$$ e#ta%$i#hed e#0ecia$$* the i)0ending

fai$ure of CT #.

Detection of PD by ultrasonic method:

Partia$ di#charge ;P< i# u#ua$$* ha00ened cau#ed %* f$a- and deterioration of tran#for)er

in#u$ation. It i# the )ain rea#on of the accident of tran#for)er and 0o-er #*#te). Therefore, it#

nece##ar* and i)0ortant to detect the 0artia$ di#charge of tran#for)er -hi$e o0erating and

)anufacturing. &hen P of tran#for)er interna$ in#u$ation occur#, e$ectro)agnetic -a"e#,

#ound -a"e# and other #igna$# are 0roduced. According to #u0er#onic #igna$, -e can detect the$ocation of P. 'ut thi# )ethod cannot te#t the nu)%er of charge. &ith u$tra#onic detection

)ethod, it i# ea#* to $ocate P and te#t the nu)%er of charge. In thi# 0a0er, a )ethod of

u$tra#onic detection i# 0re#ented, -hich i# %a#ed three?di)en#iona$ #catter 0oint and u$tra#onic

hit to ti)e. The )ethod i# effecti"e to $ocate fau$t of tran#for)er in#u$ation.

hermal imaging:

Mo#t tran#for)er# are coo$ed %* either oi$ or air -hi$e o0erating at te)0erature# )uch higher

than a)%ient. In fact, o0erating te)0erature# of 48 C for oi$?fi$$ed tran#for)er# are co))on.

Ne"erthe$e##, 0ro%$e)# -ith tran#for)er# often )anife#t the)#e$"e# in o"erheating or hot #0ot#,)a9ing ther)a$ i)aging a good too$ for finding 0ro%$e)#.

In oil-filled transformers6 monitor t&e follo%ing e(ternal components

.ig& and lo% voltage bus&ing connections O"erheating in a connection indicate# high

re#i#tance and that the connection i# $oo#e or dirt*. A$#o, co)0are 0ha#e#, $oo9ing for un%a$ance

and o"er$oading.

Cooling tubes# On oi$?coo$ed tran#for)er#, coo$ing tu%e# -i$$ nor)a$$* a00ear -ar). If one or

)ore tu%e# are co)0arati"e$* coo$, there )a* %e a 0ro%$e).


29/32

Pro%$e)# -ith #urge 0rotection and $ightning arre#tor# $ea9ing to ground and current trac9ing

o"er in#u$ator# can a$#o %e detected u#ing ther)ogra0h* and ther)a$ i)ager#.

Dor ther)a$ i)aging to %e effecti"e in 0in0ointing an interna$ tran#for)er 0ro%$e), the

)a$function )u#t generate enough heat to %e detecta%$e.

A good a00roach i# to create regu$ar in#0ection route# that inc$ude the tran#for)er# on a$$

e##entia$ e$ectrica$ circuit#. Sa"e ther)a$ i)age# for co)0ari#on and reference# of 0ro0er

o0erating e>ui0)ent.

!ltra "V Partial Discharge Detector

EA Techno$og*# U$tra TEV Partia$ i#charge etector Kit detect# %oth #urface and interna$

di#charge acti"it* -ithin )ediu) "o$tage e>ui0)ent.

The U$tra TEV etector i# a hand he$d, dua$ #en#or, Partia$ i#charge detector, -hich ena%$e#

#i)0$e fir#t 0a## identification of 0otentia$$* da)aging :V e>ui0)ent fau$t# and MV e>ui0)entfau$t# %efore the* %eco)e fai$ure#.

Precautionar' &aintenance)

The 0recautionar* )aintenance acti"itie# are underta9en on the #er"ice $ife of the co)0onent and

conducted after a fai$ure or %rea9do-n. Such )aintenance re#u$t# in outage of circuit and #u00$*.

In genera$, it con#i#t# of $ocating the trou%$e, re0air and deco))i##ioning.

Precautionar* )aintenance co"er# a -ide range of acti"itie# ai)ed at 9ee0ing the e>ui0)ent in

0erfect -or9ing condition for 0erfor)ing it# function a# 0er a##igned dutie#. The choice of

acti"itie# and #chedu$e de0end# u0on $oca$ re>uire)ent#.

Inspection# Thi# refer# to the )aintenance acti"it* -hich co)0ri#e# carefu$ o%#er"ation#crutin*

of the e>ui0)ent -ithout di#)ant$ing it. It u#ua$$* inc$ude# "i#ua$ and o0erationa$ chec9#.

Servicing# Thi# refer# to c$eaning, ad(u#t)ent, $u%rication and other )aintenance function#

-ithout di#)ant$ing the e>ui0)ent.

7(amination Thi# refer# to in#0ection -ith nece##ar* di#)ant$ing, )ea#ure)ent# and non?

de#tructi"e te#t# to o%tain data regarding the condition of co)0onent##u%?a##e)%$ie#.

+ver&aul# Thi# refer# to the -or9 done -ith the o%(ecti"e of re0airingre0$acing -orn?out 0art#and defecti"e 0art#. The e>ui0)ent, #u%?a##e)%$ie# are di#)ant$ed 0art$* or co)0$ete$*. The

condition of co)0onent# i# in#0ected. i)en#ion# of -orn?out co)0onent# are )ea#ured. The

co)0onent# -orn?out %e*ond acce0ta%$e $i)it are re0$aced. The a##e)%$* i# fo$$o-ed %*

functiona$ chec9# and )ea#ure)ent# to en#ure #ati#factor* o0eration.


30/32

Conc!usion) No- I ha"e #tudied a $ot a%out the e$ectrica$ tran#)i##ion #*#te). One )u#t ha"e ne"er thought

that #o )an* thing# are re>uired for (u#t #-itching on a te$e"i#ion or a refrigerator or #a* an

e$ectric tri))er. The three -ing of e$ectrica$ #*#te) "i=. Generation, tran#)i##ion and

di#tri%ution are connected to each other and that too "er* 0erfect$*. :ere )an and e$ectricit*

-or9 a# if the* are a fa)i$*. Lot# of $a%or, ca0ita$ and infra#tructure i# in"o$"ed in the #*#te) (u#t

to ha"e a #ing$e 0ha#e,667V,87:= 0o-er #u00$* at our hou#e#. At $a#t I -ou$d #a*... Energ*

Sa"ed I# Energ* Produced

The centra$ co)0onent of the #u%#tation i# the tran#for)er, a# it 0ro"ide# the effecti"e in enface

%et-een the high?and $o-?

"o$tage 0art# of the #*#te). Other crucia$ co)0onent# are circuit%rea9er# and #-itche#. 'rea9er#

#er"e a# 0rotecti"e de"ice# that o0enauto)atica$$* in the e"ent of a fau$t, that i#, -hen a

0rotecti"e re$a* indicate# e/ce##i"e current due to #o)e a%nor)a$ condition. S-itche# are

contro$ de"ice# that can %e o0ened or c$o#ed de$i%erate$* to e#ta%$i#h or %rea9 a connection. An

i)0ortant difference %et-een circuit %rea9er# and #-itche# i# that %rea9er# are de#igned

to interru0t a%nor)a$$* high current# ;a# the* occur on$* in tho#e "er* #ituation# for -hich

circuit 0rotection i# needed


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htt0---.edgef/.ine$ectrica$?engineering?#u%#tation?co)0onent#?and?their?-or9ing#

[email protected])e$ectrica$?circuit?%rea9er?o0eration?and?t*0e#?of?circuit?%rea9er

htt0e-h.ieee.org#oc0e#ne-*or9Ne-SitePD#Protection

J67Re$atedTran#for)erProtection.0df

htt0---.circuit#toda*.co)-or9ing?of?re$a*#

[email protected])e$ectrica$?in#u$ator?in#u$ating?)ateria$?0orce$ain?g$a##?0o$*)er?in#u$ator

htt0---.cea.nic.inre0ort#artic$e#godguide$ine#Q#huntQca0Qdi#tQ)eter#Qca%$e#[email protected]


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htt0---.-%#edc$.inir(go9)doc#internet-e%0agetech#0ecTEC:.SPEC.?ACSR.0df

htt0---.e$ectrica$0o-ereducation.co)o0eration#?)aintenancedi#tri%ution?tran#for)er?

0rotection

htt0---.e$ectrica$?engineering?0orta$.co)do-n$oad?center...0o-er?#u%#tation#

summer internship report on wbsedcl substation

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