POWER ENGINEERING AND ELECTRICAL ENGINEERING VOLUME: 11 |NUMBER: 3 |2013 |JUNE
Backup Al e na i es o 110 kV Lines
Vi HOUDEK1, S anisla RUSEK1, Radomi GONO1
1Depa men o Elec ical Powe Enginee ing, Facul y o Elec ical Enginee ing and Compu e Science,
VSB–Technical Uni e si y o Os a a, 17. lis opadu 15, 708 33 Os a a-Po uba, Czech Republic
i .houdek@cen um.cz, [email p o ec ed], [email p o ec ed]
Abs ac . The pape desc ibes backup al e na i es o
110 kV lines. Line backup is one o inpu pa ame-
e s used o op imise he eno a ion o 110 kV lines.
The op imisa ion is based on he p inciple o eliabil-
i y cen ed main enance (RCM) which depends on he
echnical condi ion and impo ance o a pa icula ele-
men . The pape s a s wi h illus a ing he me hod o
eliabili y schemes. This me hod enables he e alua ion
o ailu e- ee ope a ion p obabili y. The p obabili y o
a ailu e- ee ope a ion can be es ima ed o all backup
ypes o 110 kV lines exis ing in he dis ibu ion ne -
wo k. To compa e di e en backup al e na i es, ype
lines we e selec ed and calcula ed wi h. The esul s o
he me hod helped es ima e he e ec s o a line ailu e
o a pa icula dis ibu ion dis ic .
Keywo ds
Backup, e ec o ailu e, main enance, RCM,
eliabili y.
1. In oduc ion
Fo a oday’s consume , a eliable and ailu e- ee op-
e a ion o elec ici y ne wo k is a i al and na u al
hing. Howe e , o a dis ibu ing company espon-
sible o he sa e y and eliabili y o ne wo k, mee ing
his need is a complica ed ask liable o he “Regula-
ions o dis ibu ion ne wo k ope a ion“. I he powe
supply is in e up ed, he dis ibu ion company loses
p o i on dis ibu ion and powe supply. Mo eo e , he
dis ibu o can be ined o he ene gy unsupplied o
consume s.
To main ain he eliabili y and sa e y o ope a ion,
a dis ibu ion ne wo k mus be egula ly se iced as
pe he “Schedule o p e en i e main enance“ [1]. To
op imise main enance, eliabili y cen e ed main enance
(RCM) seems o be he mos app op ia e ool [2]. I
is based on he echnical condi ion and impo ance o
he equipmen . The e a e wo inpu pa ame e s which
help assess he impo ance o a line. Fi s ly, his pape
ou lines he back-up al e na i es o a ailed line. An-
o he inpu pa ame e is ansmi ed ene gy [3]. Also,
we p esen an e alua ion o one dis ibu ion dis ic .
2. Impo ance o Line
The possibili y o a line backup in o ms bes on he
impo ance o a line [4]. Howe e , impo ance o a
110 kV line can be also de e mined by i s losses, load o
ca ying capaci y. Backup al e na i es o a ailed line
mus be speci ied - powe can be supplied by ano he
110 kV line o an MV line. Howe e , some 110 kV lines
ha e no backup. I a line ails, localiza ion o a ailu e
and manipula ions o deal wi h ailu e, ei he manual
o emo e, mus be ca ied ou . In e ms o eliabili y,
du a ion o manipula ion is essen ial.
2.1. Reliabili y Scheme Me hod
To e alua e backup, we use p obabili y o ailu e- ee
ope a ion Rcalcula ed in he ollowing equa ion [5]:
R= 1 −
λτ
8760.(1)
To calcula e he p obabili y o a ailu e- ee ope a-
ion, ailu e a e λ(yea −1) and mean ailu e ime τ
(hou ) mus be de e mined. The calcula ion is un as
pe CEZ 22/80, bu he main enance down imes a e
neglec ed. The me hod di e si ies h ee basic ypes o
connec ing wo elemen s:
•se ies connec ion o elemen s,
•pa allel connec ion o elemen s – ho ese e,
•pa allel connec ion o elemen s – cold ese e.
1) Se ies Connec ion o Elemen s
In se ies connec ion o elemen s ailu e o one elemen
causes a ailu e o he whole sys em, e.g. ans o me
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and line connec ion:
λ=λ1+λ2,(2)
τ=λ1τ1+λ2τ2
λ.(3)
Fig. 1: Se ial connec ion o elemen s.
2) Pa allel Connec ion o Elemen s – Ho
Rese e
Ho ese e is a pa allel connec ion wi hou he use
o manipula ion. I one elemen ails, ano he elemen
akes o e i s unc ion, e.g. wo pa allel ans o me s.
To al ailu e a e and mean ailu e ime a e de e mined
as ollows:
λ=1
8760 (λ1λ2(τ1+τ2)) ,(4)
τ=λ1λ2τ1τ2
8760λ.(5)
Fig. 2: Pa allel connec ion o elemen s – ho ese e.
3) Pa allel Connec ion o Elemen s – Cold
Rese e
Cold ese e is a connec ion iden ical wi h he ho e-
se e. The connec ion is pa allel and wi h manipula-
ion, so manipula ion ime mus be included in he
calcula ion. Schema ically, he connec ion is se ial-
pa allel. Howe e , in case o a ailu e, he ese e ele-
men does no swi ch on immedia ely bu wi h a delay.
The ailu e a e o manipula ion co esponds wi h
he ailu e a e o he i s elemen . The manipula-
ion akes place i he i s elemen ails. Cold ese e
equa ions a e a combina ion o ela ions o pa allel ho
ese e and se ies combina ion.
Fig. 3: Pa allel connec ion o elemen s – cold ese e.
2.2. P obabili y o Failu e-F ee Ope -
a ion
Inpu pa ame e s o he calcula ion i sel [6], ailu e
a e and mean ailu e ime, ha e been upda ed in a
long- e m moni o ing o ailu es. The upda ed alues
a e in he ollowing Tab. 1 [7]:
Tab. 1: Inpu pa ame e s.
λ(yea −1)τ(hou )
HV line 100 km 0,282 3,155
MV line 100 km 3,623 18,759
HV/MV ans o me 0,048 74,892
Fi e di e en ypes o connec ions we e used. As we
sol e HV lines, he e a e se e al condi ions we mus
deal wi h:
•no backup,
•backup by HV line o he same leng h,
•backup by HV line o 1,5 mul iple o i s leng h,
•backup by MV line o he same leng h,
•backup by MV line o 1,5 mul iple o i s leng h.
E e y backup has wo al e na i es – one wi hou ma-
nipula ion (ho ese e), he o he wi h manipula ion
(cold ese e). Manipula ion imes a e 7 minu es o
HV backup lines and 20 minu es o MV backup lines.
HV lines o a ype we e calcula ed, he leng h o he
o iginal line is 100 km. The backup line is ei he o
he same leng h o o he 1,5 mul iple o i s leng h o
bo h HV and MV. Al oge he , nine al e na i es we e
calcula ed. The calcula ion is o he same leng h o
longe , i.e. 150 km.
1) No Backup
The scheme has one elemen . To calcula e he p ob-
abili y o ailu e- ee ope a ion, pa ame e s o 110 kV
line mus be subs i u ed in ela ion R= 0,999898434,
1.
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Fig. 4: No backup – powe and eliabili y scheme.
2) Backup by HV Line o he Same Leng h
In his case, pa allel connec ion is a ailable. This al-
e na i e can be wi h o wi hou manipula ion. Relia-
bili y scheme is used o he calcula ion o p obabili y
(Fig. 5). Fi s , pa allel combina ion is calcula ed and
hen manipula ion is added o o al calcula ion, de-
pending on he al e na i e:
•no manipula ion: R= 0,999999989,
•wi h manipula ion: R= 0,999996234.
Fig. 5: Backup by HV line – powe and eliabili y scheme.
3) Backup by HV Line o 1,5 Mul iple o
i s Leng h
Schemes a e iden ical wi h he p e ious al e na i e
(Fig. 5), backup line is longe :
•no manipula ion: R= 0,999999985,
•wi h manipula ion: R= 0,999996229.
4) Backup by MV Line o he Same Leng h
In his connec ion (Fig. 6) he e a e wo ans o m-
e s in he backup line in he se ial combina ion. This
combina ion is sol ed i s , la e he pa allel line is cal-
cula ed and inally he manipula ion depending on he
al e na i e:
•no manipula ion: R= 0,999999129,
•wi h manipula ion: R= 0,999988398.
Fig. 6: Backup by MV line - powe and eliabili y scheme.
5) Backup by MV Line o 1,5 Mul iple o
i s Leng h
The calcula ion is iden ical o he p e ious one (Fig. 6):
•no manipula ion: R= 0,999998735,
•wi h manipula ion: R= 0,999988004.
3. Backup Ranking
Wi h he help o p obabili y o ailu e- ee ope a ion,
all he al e na i es o backup we e anked (Tab. 2).
The bes backup is p o ided by backup wi hou ma-
nipula ion – ho ese e. The second is backup wi h
manipula ion - cold ese e. The wo s op ion is a line
wi h no backup. The anking illus a es heo e ical
assump ions, howe e o he inal e alua ion o op-
imisa ion accu a e da a on p obabili y o ailu e- ee
ope a ion is needed. Fo me ela i e alues o backup
al e na i es we e imp ecise and he e o e eplaced by
new ones.
The HV abb e ia ion in Tab. 2 means ha he
backup is ia HV line, l1=l2means ha he leng hs o
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Tab. 2: Backup anking.
Ranking Iden i ica ion Backup ype
No manipula ion – ho ese e
1. HV l1=l2HV line o same leng h
2. HV l1< l2HV line o 1,5 mul iple o i s leng h
3. MV l1=l2MV line o same leng h
4. MV l1< l2MV line o 1,5 mul iple o i s leng h
Wi hou manipula ion – cold ese e
5. HV l1=l2MAN HV line o same leng h
6. HV l1< l2MAN HV line o 1,5 mul iple o i s leng h
7. MV l1=l2MAN MV line o same leng h
8. MV l1< l2MAN MV line o 1,5 mul iple o i s leng h
O he
9. No No backup
he backed up line and he backup lines a e he same,
l1< l2means ha he leng h o he backup line is 1,5
longe han ha o he backed up line. Backups us-
ing MV lines a e ma ked MV. The MAN abb e ia ion
means ha he backup is wi h manipula ion. Theo e -
ical indings o anking o all backup al e na i es can
be used o de e mine line impo ance o a pa icula
ne wo k. P ima ily i can be used as a weigh c i e ion
o he inal algo i hm.
4. E ec o Line Failu e
To op imise eno a ion o 110 kV in, algo i hms on he
basis o eliabili y cen e ed main enance mus be de e -
mined. Backup al e na i es we e de e mined o e e y
line in a dis ibu ion dis ic . The abo e men ioned
me hod was used o do ha . The possibili y o backup
was subs i u ed by he e ec o a line ailu e. This e -
ec o ailu e ells us wha happens a e a line ails.
In heo e ical analysis educed ansmi ed powe was
neglec ed. Howe e , in a inal ield e alua ion his pa-
ame e mus be aken in o accoun . Ano he eason
o using he e ec o ailu e is ha i gi es a be e
pic u e o he line backup.
The e ec s o ailu e we e discussed and de e mined
by he echnicians ope a ing in he dis ibu ion dis ic
and hey co espond wi h he ield p ac ice. The e a e
no exis ing lines wi hou a backup in he a ea. Al o-
ge he , se en ypes o e ec s o ailu e exis :
•1: ”No e ec ” – no manipula ion necessa y,
•2: Back-up by 110 kV line o app ox. he same
leng h,
•3: Back-up by 110 kV line o app ox. he same
leng h wi h limi ed powe ,
•4: Back-up by a longe 110 kV line,
•5: Back-up by a longe 110 kV line - limi ed powe ,
•6: Back-up by MV line,
•7: Back-up by MV line - limi ed powe .
The e a e o al o 168 powe lines in one dis ibu ion
ne wo k. The esul s o e alua ion a e shown in Tab. 3
and in ba g aph (Fig. 7). Ba g aph does no show
he e ec numbe 7, because he alue is ze o.
Fig. 7: E ec o line ailu e – ba g aph.
The e alua ion shows ha app ox. 56 % o lines
equi e no manipula ion. In ac , hese lines a e backed
up by pa allel lines which a e pe manen ly connec ed.
Theo e ically, we speak abou a ho ese e. The e a e
72 lines which equi e manipula ion a e a ailu e, and
a e ha ull load can be ansmi ed. Only wo lines
a e backed up by lines which ca y educed load. The e
a e nine lines ha a e backed up by MV lines.
Tab. 3: Inpu pa ame e s.
E ec o Failu eCoun [-] Coun [%]
1 94 55,95
2 51 30,36
3 1 0,60
4 12 7,14
5 1 0,60
6 9 5,36
7 0 0,00
To al o : 168
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Also, du ing manipula ion, lines can only ca y e-
duced load and he e o e he du a ion o manipula ion
is impo an . Backup ia HV line needs max. 20 min.
manipula ion and backup ia lowe ol age lines may
need as much as minu es manipula ion.
5. Conclusion
Theo e ical assessmen o sequencing di e en backups
will be used as a weigh c i e ion in he algo i hm o
op imised eno a ion o 110 kV line. The line backup
is exp essed by he e ec o a ailu e.
The weigh will show how impo an a pa icula
alue o a ailu e e ec is. In case o he bes backup
al e na i e 1, his pa ame e is insigni ican . On he
con a y, he alue is i al in case o backup al e na-
i e 5. The echnical condi ion is assessed on he basis
o he ailu e da abase. Impo ance o a line is de e -
mined by ansmi ed ene gy and possibili y o backup.
The pape ou lines backup al e na i es o 110 kV
lines in one dis ibu ion a ea. This a ea was e alua ed
in he p e ious sec ion. O e all, app oxima ely 56 %
o lines ha e adequa e backup and he e o e equi e
no manipula ion in he dis ibu ion ne wo k. On he
con a y, lines wi h dec eased load backup a e ew.
Acknowledgmen
This wo k was suppo ed by he Czech Science Foun-
da ion (No. 102/09/1842), by he G an o SGS VSB-
Technical Uni e si y o Os a a (No. SP2013/137) and
by he p ojec ENET (No. CZ.1.05/2.1.00/03.0069).
Re e ences
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[2] MOUBRAY, J. Reliabili y-cen e ed main enance.
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ISBN 978-083-1131-463.
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Abou Au ho s
Vi HOUDEK was bo n in Ch udim. In 2011
he g adua ed VSB–Technical Uni e si y o Os a a,
Facul y o Elec ical Enginee ing and Compu e
Science, elec ical powe enginee ing. Today he is
Ph.D. s uden in he Depa men o Elec ical Powe
Enginee ing, VSB–Technical Uni e si y o Os a a
and he applies himsel o he issue o eliabili y o
elec ical ne wo ks.
S anisla RUSEK was bo n in Ha i o -Sucha.
In 1981 he g adua ed VSB–Technical Uni e si y
o Os a a, Facul y o Mechanical Enginee ing and
Elec ical Enginee ing, powe enginee ing ield. He
g adua ed scien i ic pos g adua e a Facul y o Elec i-
cal Enginee ing and Compu e Science B no, elec ical
machines and de ices, in 1989. Pos -g adua e educa-
ion a Facul y o Science Palacky Uni e si y Olomouc
in uni e si y educa ion g adua ed in 1991. He was
habili a ed a he Facul y o Elec ical Enginee ing
and Compu e Science, VSB–Technical Uni e si y o
Os a a in 1991. He is p o esso om 2001.
Radomi GONO was bo n in Bilo ec. In 1995
he g adua ed om VSB–Technical Uni e si y o Os-
a a, Facul y o Elec ical Enginee ing and Compu e
Science. He ecei ed his Ph.D. om VSB–Technical
Uni e si y o Os a a in 2000. He was habili a ed
a Facul y o Elec ical Enginee ing and Compu e
Science, VSB–Technical Uni e si y o Os a a in 2008.
Today he is ice-head o he Depa men o Elec ical
Powe Enginee ing. Resea ch wo k is ocused on
eliabili y o elec ic powe sys ems and enewable
ene gy sou ces.
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