Transmission Maintenance

7/26/2019 Transmission Maintenance

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Single Point of Failure (SPOF)

Transmission - Maintenance



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Denition

What does Single Point of Failure

(SPOF) mean

! single "oint of failure (SPOF) is a critical

s#stem com"onent $ith the a%ilit# to cease

s#stem o"erations during failo&er' SPOFs are

undesira%le to s#stems reuiring relia%ilit# and

a&aila%ilit#'

ighl# relia%le s#stems are designed $ithout

SPOFs' This means that failure of a com"onent*

eui"ment* s#stem or site does not halt s#stem



+

+

,ategories of SPOF

Permanent

• Single D, Source forthe Main and ac.u"Protection'

• T- ,onnection To"olog#

of the Transmission/ines'• Design at ,om"onent 0

S#stem le&el notmeeting the Targetedelia%ilit# le&el e'g' n-13'

• Soft$are ugs for the

Man# de&ices from oneManufacturer'

• Single Protection,ommunication,hannel 0 Media ordou%le at the sameroute'

•

Dou%le or more O/,ircuits on one to$er(or ca%les in one

Temporary

• Mo%ile Transformers'

• Planned 0 4mergenc#Shutdo$n e5ecting the

Targeted elia%ilit#le&el e'g' n-13'

• 6rgent 4nergi7ation ofSingle Su""l#!rrangement to feedthe customers'

Special• Single Point of Failure

(SPOF) that leads to a,ommon Point ofFailure (,POF) in the

8et$or.' !n# ,ritical"oint in the s#stemthat e9"eriences morefreuent distur%anceslead to $ide area orma:or incident' i'e'cascaded tri""ing dueto O&erloading or *

Oscillation Phenomena'



;

;

S<8=/4 D, SO6,4 FO T4 M!<8!8D !,>6P POT4,T<O8

!ll the under s"ecied "oints can %e sorted as SPOFof Single D, Source for The Main ? ac.u"

Protection@• Single atter# an. in the Su%station'

• The Main and ac.u" Protection are fed from thesame M,* although the e9istence of another D,Source'

• Single atter# ,harger in the su%station'

• Sole !u9iliar# Transformer'



A

A

T- ,O884,T<O8 TOPO/O=B OF T4T!8SM<SS<O8 /<84S'

O/-T- ,onnection

Feeding three su%stations %# one O/ circuit*an# fault on the O/ circuit $ill ,ause tri""ing onall three su%stations'

The relia%ilit# ad&ersel# a5ected'



C

C

S<8=/4 POT4,T<O8 ,OMM68<,!T<O8,!884/ 0 M4D<! O DO6/4 !T T4S!M4 O6T4'• !s sho$n in %elo$ gure (84TWO> F68,T<O8!/

D<!=!M ) * $e can see that S0S CE1 "h#sicall#

connected to communication net$or. through onl#o"tical %er ca%le to S0S E+G and %oth routes of scadato that S0S "ass through the same %er as acommunication media and the same o"tical eui"ment$hich means that during failure of either o"tical ca%le oro"tical eui"ment $e shall loose communication to s0s

CE1'• !lso if d'c' su""l# for telecom eui"ment lost at an# s0s

$e shall loose communication '

• For "rotection "ath an alternati&e %er route and s#stema&aila%ilit# is reuired' <n case of linear (adial ) lin.s

$e donHt ha&e choice to "rotect the traIc'



GG

SPOF 4J!MP/4@ S0SHs CE1*GCE1*CEC ? CE+ !K4 /<84!

,O884,T<O8 PO<8TS' TraIc e-routing not "ossi%le

"h#sicall# %# ca%le onl# &irtuall# %# 8MS'



DO6/4 O MO4 O/ ,<,6<TS O8O84 TOW4 (O ,!/4S <8 O84T48,) !S ! S<8=/4 F44D TO ! /O!D'

Single feed ( radial line) * dou%le circuits on singleto$er

• !n# mechanical damage on an# to$er $ill causeloss of su""l# to su%station'

,a%les in one trench

• !n# mechanical damage in an# ca%le $ill causeloss of su""l# to su%station'



SPOF ,ollected Data ,om"letion Solution,O! 4O! WO! SO!

Single Protectioncommunicationchannel0 media ordou%le at thesame route

A'+ L

8o' of SPOF+20A;

1EE L

8o' of SPOF+A0+A

1EE L

8o' of SPOFG10G1

1EE L

8o' of SPOF21021

Not Yet

Single D, Sourcefor the Main andac.u"

Protection

C;'2 L

C10A

Dec +1* 2E1A

E L

E011E

Nul +1* 2E1C

1EE L

202

1EE L

A0A

Not Yet

T- ,onnectionTo"olog# of theTransmission/ines

1EE L

C0C

1EE L

2A02A

E L

E01A

Nan +1* 2E1C

1EE L

0

Not Yet

Dou%le or moreO/ ,ircuits onone to$er (orca%les in oneTrench) as asingle feed to aload

1EE L

;10;1

1EE L

1E101E1

;2'1 L

01

Nan +1* 2E1C

1EE L

2G02G

Not Yet

Data To %e ,om"leted %# Nul# 2E1C as "er !reasHTSD



1E1E

49am"le of Solution

SPOFs are identied and resol&ed throughredundant and high-a&aila%ilit# of the s#stem or

its com"onents' For e9am"le* u"on tri""ing ofeui"ment* another eui"ment immediatel#ta.eo&er res"onsi%ilit#' edundanc# are

em"lo#ed at internal com"onent le&el* site le&elas $ell as s#stem le&el'

Transmission Maintenance

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