Electrical Substation General Equipments

SUBSTATION HIGH VOLTAGE COMPONENTS POWER PLANT SWITCHING SWITCHI NG ST STA ATION (SWITCHYARD)

SUBSTATION •

SUBSTATION  - A station in the power transmission

system at whih e!etri power is trans"orme# to a on$enient!y %se# "orm& The station may onsist o" trans"ormers' swithes' ir%it (rea)ers an# other a%*i!!iary e+%ipment& Its main "%ntion is to reei$e ener,y transmitte# at hi,h $o!ta,e "rom the ,eneratin, station' (y either step-%p or step-#own the $o!ta,e to a $a!%e appropriate "or !oa! %se an# pro$i#e "ai!ities "or swithin,& S%(stations ha$e some a##itiona! "%ntions& Its pro$i#e points where sa"ety #e$ies may (e insta!!e# to #isonnet ir%its or e+%ipment in the e$ent o" tro%(!e& Some substation, such as power plant switchyard are simply switching stations where diferent connections can be made between various transmission lines.

 Typia!  Typia! Components Components o" a Power Power P!ant S%(station Swithyar#. •

CONNECT

A - Busbar 

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 CONNECT & DIS-CONNECT

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 CONNECT, DIS-CONNECT & DETECT

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 DETECT & TRANSFORM

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 DETECT & TRANSFORM

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 PROTECT & SAFETY

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 PROTECT

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B - Disconnector

C - Circuit Breaker  D - Current Transformer 

E - Voltage Voltage Transformer 

F - Earthing Switch G - Surge Arrestor 

A& BUSBA/ •

BUSBAR (or bus, or short) 0 short)  0 is a term we %se "or a

main (ar or on#%tor arryin, an e!etri %rrent to whih many onnetion may (e ma#e& B%ses are mere!y on$enient means o" onnetin, swithes an# other e+%ipment into $ario%s arran,ements& The %s%a! arran,ement o" onnetions in most s%(stations permit wor)in, on a!most any piee o" e+%ipment witho%t interr%ption to inomin, or o%t,oin, "ee#ers& In the swithyar# or s%(station' (%ses are open to the air& A!%min%m or opper on#%tors s%pporte# on pore!ain ins%!ators' arry the e!etri ener,y "rom point to point& poi nt&

Busbars (long heavy  tube type)

B& 1ISCONNECTS •

DISCONNECT 0 is an easi!y remo$e# piee o" the

at%a! on#%tor o" a ir%it& The p%rpose o" #isonnets is to iso!ate e+%ipment& 1isonnets are not %se# to interr%pt ir%its2 they are no-!oa# #e$ies& A typia! %se o" #isonnets is to iso!ate a ir%it (rea)er (y insta!!in, one #isonnet on either si#e o" the ir%it (rea)er in series with the (rea)er.& Operation o" #isonnets is one o" the most important an# responsi(!e 3o(s o" a power p!ant operator& One error in iso!ation o" e+%ipment' or the ai#enta! ,ro%n#in, o" !ine e+%ipment' an (e a "ata! mista)e&

Disconnect Switc ( moving contact rod (A) & contacts with flexible fingers (B) )

B

A

C& CI/CUIT B/EA4E/ •

CIRCUIT BREAKER 0 is %se# to interr%pt ir%its whi!e

%rrent is 5owin, thro%,h them& The ma)in, an# (rea)in, o" ontats in a Oi! type ir%it (rea)er are #one %n#er oi!' this oi! ser$es to +%enh the ar when the ir%it is opene#& The operation o" the (rea)er is $ery rapi# when openin,& As with the trans"ormer' the hi,h $o!ta,e onnetions are ma#e thro%,h (%shin,s& Cir%it (rea)ers o" this type are %s%a!!y arran,e# "or remote e!etria! ontro! "rom a s%ita(!y !oate# swith(oar#& Some reent!y #e$e!ope# ir%it (rea)ers ha$e no oi!' (%t p%t o%t the ar (y a (!ast o" ompresse# air2 these are a!!e# air ir%it (rea)ers& Another type en!oses the ontats in a $a%%m or a ,as s%!"%r he*a5%ori#e' S6 7. whih ten#s to se!" maintain the ar&

Circuit Brea!ers ( Connected in a typical 3phase circuit )

"osition #ndicator

perating !echanism "anel

1& CU//ENT T/ANS6O/ME/ •

0 C%rrent trans"ormer are %se# with ammeters' watt meters' power-"ator meters' watt-ho%r meters'ompensators' proteti$e an# re,%!atin, re!ays an# the trip oi! o" ir%it (rea)ers& One %rrent trans"ormer an (e %se# to operate se$era! instr%ments' pro$i#e# that the om(ine# (%r#en #oes not e*ee# that "or whih the trans"ormer is #esi,ne# an# ompensate#& The %rrent trans"ormer is onnete# #iret!y in series with the !ine& CURRENT

TRANSFORMER

E& VOLTAGE T/ANS6O/ME/ •

VOLTAGE TRANSFORMER 0 a!so )now as potentia!

trans"ormer' trans"ormer' are %se# with $o!t-meters' wattmeters' watt-ho%r meters' power-"ator meters' "re+%eny meters' synhrosopes an# synhroni8in, apparat%s' proteti$e an# re,%!atin, re!ays an# the no-$o!ta,e an# o$er-$o!ta,e trip oi!s o" a%tomati ir%it (rea)ers& One trans"ormer an (e %se# "or a n%m(er o" instr%ments at the same time i" the tota! %rrent ta)en (y the instr%ment #oes not e*ee# that "or whih the trans"ormer is #esi,ne# an# ompensate#& The or#inary $o!ta,e trans"ormer is onnete# aross the !ine' an# the ma,neti 5%* in the ore #epen#s %pon the primary $o!ta,e

6& EA/THING S9ITCH •

EARTHING

SWITCH

0 a!so )nown as ,ro%n# #isonnet' whih %se# to onnets the e+%ipment to a ,ri# o" e!etria! on#%tors (%rie# in the earth on the station property& property& It is inten#e# to protet peop!e wor)in, on the ,ro%n#e# e+%ipment& It #oes this (y omp!etin, a ir%it path' there(y re#%in, the $o!ta,e #i:erene (etween the e+%ipment an# its s%rro%n#in,s& 6or sa"ety reasons' it is important that ,ro%n# #isonnets an# a!! assoiate# onnetions ha$e ,oo# ontat an# !ow resistane& It is a!so important that the proteti$e ,ro%n# not (e ai#enta!!y remo$e' that is why a!! the earthin, swithes' #isonnet swithes an# ir%it (rea)ers are a!! inter!o)e# to eah other an# proper;orret se+%enin, m%st (e "o!!owe#&

G& SU/GE A//ESTO/ •

SURGE ARRESTOR 0 are #e$ies %se# to pro$i#e the

neessary path to ,ro%n# "or s%h s%r,es' yet pre$ent any power %rrent "rom "o!!owin, the s%r,e& An i#ea! arrester m%st there"ore ha$e the "o!!owin, properties< =& A(i!ity to remo$e the s%r,e ener,y "rom the !ine in a min& time& >& Hi,h resisti$e to 5ow o" power %rrent& ?& A $a!$e ation a%tomatia!!y a!!owin, s%r,e to pass an# then !osin, %p so as not to permit power %rrent to 5ow to ,ro%n#& @& A!ways rea#y to per"orm& & Per"ormane s%h that no system #ist%r(anes are intro#%e# (y its operation& 7& Eonomia!!y "easi(!e

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OVERHEAD GROUND WIRE 0 (y a ,ro%n# wire

is meant a wire' ,enera!!y o" stee!' s%pporte# "rom the top o" transmission-!ine towers an# so!i#!y ,ro%n#e# at eah tower& It is onsi#ere# a pre$enti$e #e$ie' (%t it #oes not entire!y pre$ent the "ormation o" tra$e!!in, wa$es on a !ine& 6%rthermore' those !ines whih are not e+%ippe# with ,ro%n# wires wi!! (e s%(3ete# to #ist%r(anes whih pro#%e s%r,es that m%st (e a!!owe# to esape# to ,ro%n#' or the apparat%s onnete# to the !ine m%st (e stron, eno%,h to re5et or a(sor( these s%r,es %nti! they are entire!y #ampe# o%t&

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   

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PREVENTIVE MAINTENANCE BUSBA/S  OVE/HEA1 G/OUN1 9I/E  At least once once a year  year  Vis%a! Inspetion  E*amination o" a!! wirin, onnetors& Che) Ins%!ator ' !ean or app!y HVIC i" neessary& Che) the physia! on#ition o" (%s a(!es or (ars. 6or ,ro%n# wire' he) or test the ,ro%n#in, system&

1ISCONNECT  EA/THING S9ITCHES

 At least once once a month month  Vis%a! Inspetion&  Che) heatin, resistor !oate# at its ontro! pane! "or proper "%ntionin,&  At least once once a year   C!ean ontats o" #isonnetors as we!! as earthin, swithes an# app!y e!etria! ontat ,rease ' i" neessary&

 Che)

#isonnetors an# earthin, swithes' 3oints an# (earin,s o" the operatin, !in)a,es "or #e"orme# (earin, points&  Che) 5e*i(!e onnetions o" earthin, swithes&  Che) a!! srewe# 3oints "or ti,ht t&  C!ean ins%!ators i" neessary' when an e*essi$e amo%nt o" #irt has a%m%!ate#&  Carry-o%t the maintenane o" operatin, mehanism&

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VOLT VOLTAGE T/ANS6O/ T/ANS6O/ME ME/ /

 At least once a month  Inspet the $o!ta,e #i$i#er to (e s%re that no oi! !ea) or serio%s a%m%!ation o" soot' #%st or sa!t omposite is present& present&  Inspet the interme#iate $o!ta,e trans"ormer an# he) the minim%m permissi(!e permissi(!e oi! !e$e!&  At least once a year   Che) a!! srewe# 3oints  ontat "or ti,ht t&  C!ean ins%!ators i" neessary' when an e*essi$e amo%nt o" #irt has a%m%!ate#&

CU//ENT T/ANS6O/ME/ T/ANS6O/ME/  At least once a month  Vis%a! Inspetion to he) oi! !e$e! an# #e"ets or possi(!e oi! !ea)s&  At least once a year   Che) a!! srewe# 3oints  ontat "or ti,ht t&  C!ean ins%!ators i" neessary' when an e*essi$e amo%nt o" #irt has a%m%!ate#&  Che)

primary an# seon#ary onnetors an# on#%t neessary ti,htenin,& Note< Never open a secondary winding o a C while on service.

SU/GE A//ESTO/

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 At least once a year  Vis%a! Inspetion  E*amination o" a!! wirin, onnetors& Che) Ins%!ator an# meta! ir%!ar rin,' !ean or app!y HVIC i" neessary& Che) the physia! on#ition o" (%s a(!es or (ars.

 6or

,ro%n# wire' he) or test the ,ro%n#in, system& Note< Arrestors sho%!# ne$er (e to%he# %n!ess omp!ete!y #isonnete# "rom "rom a!! !i$e !ines an# e+%ipment an# e:eti$e!y onnete# to ,ro%n# at the !ine si#e o" the arrestor&