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8/12/2019 Ee 360 Lecture Presentation(Copy)
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By
E. A. Frimpong
EE 360 HIGH VOLTAGE ENGINEERING(3 0 3)
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COURSE CONTENT
Propertie o! "ig" #o$t%ge in&$%tion %n' re%'o*n p"enomen%in m%teri%$ %n' %ir *it" 'i!!erent type o! e$e+tro'e
Tr%nient- $ig"tning p"enomen% &rge in tr%nmiion $ine'&e to $ig"tning %n' *it+"ing. Prote+tion o!
e/&ipment%pp$i%n+e %g%int &+" tr%nient.
Tr%n!ormer- H%rmoni+% &n%$%n+e' $o%'ing 31*in'ing HVtr%n!ormer imp&$e teting.
Hig" #o$t%ge tet e/&ipment in+$&'ing imp&$e gener%tor %.+.%n' '.+. HV tet et %n' port%$e in&$%tion tet et &e' inin'&trie !or oi$ %n' ot"er in&$%tion teting. 2etr&+ti#e %n'non1'etr&+ti#e teting in+$&'ing p%rti%$ 'i+"%rge te+"ni/&e.App$i+%tion o! HV te+"ni/&e in io1me'i+%$ engineering.
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COURSE INTRODUCTION
T"e r%pi'$y in+re%ing tr%nmiion #o$t%ge $e#e$in re+ent 'e+%'e i % re&$t o! t"e gro*ing'em%n' !or e$e+tri+ po*er %n' 'it%nt po*erp$%nt.
Hig" #o$t%ge permit gre%ter po*er tr%n!er *it"minim&m $oe
It i imper%ti#e to g%in &n'ert%n'ing in %re%&+" % "ig" #o$t%ge in&$%tion "ig" #o$t%ge tet%n' tet e/&ipment.
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HV INSULATION
P&rpoe o! e$e+tri+%$ in&$%ting m%teri%$ in&$%te t"e $i#e p%rt o! e$e+tri+%$
int%$$%tion !rom one %not"er in&$%te t"e $i#e p%rt o! e$e+tri+%$
int%$$%tion !rom e%rt"e' tr&+t&r%$+omponent
Pre#ent e$e+tri+ "o+ In&$%tion $e#e$ %!!e+t e/&ipment /&%$ity
%n' +otForm o! in&$%tion('ie$e+tri+)- g%eo&
$i/&i' or o$i'
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ELECTRICAL PROPERTIES OF
DIELECTRICS
on'&+ti#ityA me%&re o! +&rrent +%rrying +%p%i$ity2etermine' y reit%n+e- reiti#ity
$engt"(t"i+ne) %n' +ro1e+tion%$ %re%on'&+ti#ity m&t e $o*($o* $e%%ge +&rrent)In&$%tion reit%n+e 'epen'- temper%t&re
"&mi'ity &r!%+e +ont%min%tion
In&$%tion reit%n+e me%&re' &ing %nin&$%tion reit%n+e teter
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ELECTRICAL PROPERTIES OF
DIELECTRICS
2ie$e+tri+ $o A me%&re o! e$e+tri+ energy %ore'
E#i'en+e' y "e%t
4&t e $o*
= power loss in the dielectric (in watts )= !pplied "olt!#e (in volts )
= !n#$l!r %re&$enc' = is the %re&$enc' o% the !pplied "olt!#e
= c!p!cit!nce o% the dielectric (in Farads).
= dielectric or loss %!ctor
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ELECTRICAL PROPERTIES OF
DIELECTRICS
2ie$e+tri+ $o (+ont.)
Lo !%+tor
w
r
Itan
I
=
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ELECTRICAL PROPERTIES OF
DIELECTRICS
E5%mp$e
A F 'ie$e+tri+ i &7e+te' to % 8kV
0Hz #o$t%ge. 2etermine t"e 'ie$e+tri+$o i! t"e $o !%+tor o! t"e 'ie$e+tri+ i0.09.
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ELECTRICAL PROPERTIES OF
DIELECTRICS
2ie$e+tri+ $o- (+ont.) Lo !%+tor- T"e gre%ter t"e $o !%+tor %$$
ot"er !%+tor eing e/&%$ t"e "ig"er t"e
'ie$e+tri+ $o t"%t i t"e poorer t"e /&%$ityo! t"e 'ie$e+tri+. Lo !%+tor i in!$&en+e' y temper%t&re
%n' moit&re
Typi+%$ $o !%+tor !or tr%n!ormer in&$%tion%t 800 0 H: r%nge !rom 0.00 to 0.08.
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ELECTRICAL PROPERTIES OF
DIELECTRICS
Permitti#ityA me%&re o! 'ie$e+tri+ po$%ri%tion2ie$e+tri+ po$%ri%tion i t"e e$%ti+
'ip$%+ement o! e$e+tri+ +"%rge &n'er t"ein!$&en+e o! e$e+tri+ !ie$' !or+e
Hig" po$%ri%tion imp$ie "ig" +%p%+it%n+e%n' "en+e "ig" energy tore
T"e 'ie$e+tri+ po$%ri%tion i /&%ntit%ti#e$ye#%$&%te' in term o! t"e re$%ti#epermitti#ity .
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ELECTRICAL PROPERTIES OF
DIELECTRICS
Permitti#ity (+ont.) Permitti#ity m&t e $o*
Permitti#ity i in! $&en+e' ytemper%t&re %n' !re/&en+y
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ELECTRICAL PROPERTIES OF
DIELECTRICS
E$e+tri+ !ie$' trengt"A me%&re o! #o$t%ge *it"t%n' +%p%i$ity In+re%ing #o$t%ge %+ro in&$%tor re'&+e
it trengt"Vo$t%ge %t *"i+" re%'o*n o++&r i +%$$e'
re%'o*n #o$t%ge
E$e+tri+ !ie$' trengt" m&t e "ig"E$e+tri+ !ie$' trengt" in+re%e *it"in+re%ing m%teri%$ t"i+ne
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ELECTRICAL PROPERTIES OF
DIELECTRICS
E$e+tri+ ! ie$' trengt"(+ont.)
ExampleA 'ie$e+tri+ o! t"i+ne mm i &7e+t to %re%'o*n #o$t%ge o! 900V. 2etermine t"ere%'o*n tre on it.
= electric (re!)down stress *in kV/mm+
= electric (re!)down "olt!#e *in kV+
= thic)ness o% the dielectric *in mm+
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NON,ELECTRICAL PROPERTIES OF
DIELECTRICS
T"erm%$ t%i$ity He%t *it"t%n' +%p%i$itie
Ageing o! m%teri%$ +%n re&$t !rome5po&re to "e%t2ie$e+tri+ m&t e t"erm%$ t%$eoo$ing i emp$oye' to impro#e t"erm%$
t%i$ity
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NON,ELECTRICAL PROPERTIES OF
DIELECTRICS
"emi+%$ e"%#io&r Re$%te to e!!e+t o! oper%ting en#ironment on
'ie$e+tri+
O5i'%tion %n' "y'ro$yi +%n %rie o++&r ;$tr%#io$et reit%n+e i re/&ire' *"en
'ie$e+tri+ i e5poe' to r%'io%+ti#e e$ement orroion %n' o$#ent reit%n+e %re %$o e
re/&ire'
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INSULATION -REA.DO/N
2e!inition- T"e $o o! in&$%ting propertie
Ho* it "%ppen- Intro'&+tion o! +on'&+ti#e&t%n+e ioni%tion or ot"
%&e-He%t imp&ritie Hig" #o$t%ge "ig"!re/&en+ie e5po&re to r%'i%tion
E!!e+t-
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-REA.DO/N IN 0ASES
TO=N2O=N PROE
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-REA.DO/N IN 0ASES
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-REA.DO/N IN LI1UIDS
Li/&i' "%#e "ig"er 'ie$e+tri+ trengt" t"%n g%e
Li/&i' %re &&%$$y +ont%min%te'%tegori%tion o! imp&ritie
Imp&ritie *"i+" "%#e re%'o*n trengt"$o*er t"%n t"%t o! t"e $i/&i' ite$!
T"e e$e+tri+ !ie$' E in % g% &$e *"i+" iimmere' in % $i/&i' o! permitti#ity 9
i gi#en y
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-REA.DO/N IN LI1UIDS
Imp&ritie o! $o* trengt"o G% e$ong%tiono re%'o*n o! g% +%&e 'e+ompoition o!
mo$e+&$e
Imp&ritie *"i+" %re &nt%$e in t"e e$e+tri+!ie$' (eg- g$o&$e o! *%ter).
o re&$t in % $o* reit%n+e ri'ge %+rot"e e$e+tro'e
Imp&ritie *"i+" re&$t in $o+%$ en"%n+ement o!e$e+tri+ ! ie$' in % $i/&i' (eg- +on'&+tingp%rti+$e).
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-REA.DO/N IN SOLIDS
E$e+tro1me+"%ni+%$ re%'o*n A me+"%ni+%$ !or+e gener%te' '&e to
!or+e o! %ttr%+tion n &r!%+e +"%rge Re'&+tion in 'ie$e+tri+ t"i+ne '&e to
%pp$ie' e$e+tri+ !ie$'
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-REA.DO/N IN SOLIDS
Bre%'o*n '&e to intern%$ 'i+"%rge Preen+e o! #oi' o! *e% 'ie$e+tri+
trengt" %roni%tion %n' eroion re&$ting
!rom 'i+"%rge %roni%tion %n' eroion re&$t in
re'&+tion o! 'ie$e+tri+ t"i+ne
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-REA.DO/N IN SOLIDS
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-REA.DO/N IN SOLIDS
Tr%+ing- !orm%tion o! % perm%nent+on'&+ting p%t" %+ro % &r!%+e o! t"ein&$%tion
Eroion- Re&$t !rom #o$%ti$e'e+ompoition
T"erm%$ re%'o*n- E5+ei#e "e%t in'ie$e+tri+
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-REA.DO/N IN SOLIDS
T"erm%$ re%'o*n-(+ont.)
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-REA.DO/N IN SOLIDS
E$e+tro1+"emi+%$ re%'o*nno 'ie$e+tri+ i !ree !rom ionion re%+t *it" e$e+tro'ee!!e+t o! e$e+tro$yi
%tt%+ on 'ie$e+tri+ %n' e$e+tro'e re$e%e o! g%e 'epoition o! &t%n+e on e$e+tro'e
r%te o! e$e+tro$yi i gre%ter *it" 'ire+t tre
t"%n *it" %$tern%ting tre
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-REA.DO/N IN SOLIDS
"emi+%$ 'eterior%tion
+"emi+%$ int%i$ity- pont%neo& re%'o*n o! t"etr&+t&re o! 'ie$e+tri+ epe+i%$$y %t "ig" temper%t&re
o5i'%tion- re&$t in poi$e &r!%+e +r%+ in !ore5%mp$e po$yet"y$ene %n' r&er
"y'ro$yi- re&$t in 'eterior%tion o! 'ie$e+tri+m%teri%$ in+omp%tii$ity-eg. R&er %ge %t e$e#%te'
temper%t&re in t"e preen+e o! +opper
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TRANSFOR2ER INSULATION
Tr%n!ormer Oi$F&n+tion-o In&$%te
o
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TRANSFOR2ER INSULATION
F%+tor %!!e+ting oi$ /&%$ityinter!%+i%$ tenion%+i'ity
reit%n+e to o5ygenreit%n+e to 'epoit !orm%tionpo*er !%+tor
'ie$e+tri+ trengt"
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TRANSFOR2ER INSULATION
%&e o! oi$ 'egr%'%tionHe%to o&r+e1+opper %n' iron $oeo
e!!e+t1'eterior%tion o! in&$%tionO5ygeno o&r+e1%ir &$e +%pt&re' !rom p&mping oi$
$e% in p&mp *%rming &p o! +oreo
e!!e+t1!orm%tion o! $&'ge
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TRANSFOR2ER INSULATION,C!se
st$d'
%&e o! oi$ 'egr%'%tion(+ont.)4oit&reo
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TRANSFOR2ER INSULATION
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TRANSFOR2ER INSULATION
PB in tr%n!ormer oi$(+ont.)Goo' propertie-
o Fire reit%n+e
o
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TESTS ON TRANSFOR2ER OIL
2ie$e+tri+ tet4e%&re t"e #o$t%ge %t *"i+" re%'o*n
o++&r
A+i'ity tet4e%&re t"e %+i' +ontent o! t"e oi$
It i re+ommen'e' to re+$%im oi$ *"en %+i'n&mer re%+"e 0.80mg>OHgm
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TESTS ON TRANSFOR2ER OIL
Po*er !%+tor tetPo*er !%+tor o! tr%n!ormer oi$ gi#e %n
in'i+%tion o! it 'ie$e+tri+ $o
A "ig" po*er !%+tor in'i+%te'eterior%tion %n'or +ont%min%tion *it"moit&re +%ron et+.
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TESTS ON TRANSFOR2ER OIL
Inter!%+i%$ tenion tetA tet o! inter!%+i%$ tenion o! *%ter
%g%int oi$
In'i+%te t"e %+t&%$ $&'ging +on'itiono! oi$
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TREAT2ENT OF TRANSFOR2ER
OIL
Appro%+"e to oi$ tre%tmentPre#enti#e ? ontin&o& oi$ re+$%m%tion
Advantages
o
Oi$ %n' p%per 'egr%'%tion pro'&+t %re remo#e'% t"ey %re !orme'oT"e o#er%$$ +on+entr%tion o! moit&re %n'
o5ygen in oi$ i m%int%ine' %t $o* $e#e$ t"&ret%r'ing t"e %ging pro+e oi$
oA&to +%t%$yti+ o5i'%tion %n' "y'ro$yi re%+tion%re re'&+e'.
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TREAT2ENT OF TRANSFOR2ER
OIL
oT"e migr%tion o! %'ore' pro'&+t!rom p%per to oi$ i promote' y t"e'yn%mi+ e/&i$iri&m m%int%ine'
et*een t"e t*o p"%eDisadvantages
oT"ere i in+re%e in o#er%$$ po*er
+on&mption '&e to +ontin&o&r&nning o! t"e p&ri!i+%tion ytemo It i re$%ti#e$y e5peni#eo It re/&ire more monitoring to e 'one
on t"e ytem
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TREAT2ENT OF TRANSFOR2ER
OIL
orre+ti#e? Perio'i+ oi$ re+$%m%tionO!!1$ine %n' On1$ine tre%tment met"o'O!!1$ine tre%tment met"o'
Fi$ter1preing t"e oi$ ? Remo#%$ o! o$i' p%rti+$e%n' !ree *%terRetro!i$$ing ? "%nging oi$ +omp$ete$y ;nt%ning &nit !$&"ing t"e t%n r%'i%tor +ore
%n' +oi$ ytem *it" o$#ent t"en re!i$$ing t"e&nit *it" ne* oi$
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PARTIAL DISCHAR0ES IN DR3
T3PE TRANSFOR2ERS
2ry type tr%n!ormer %re &&%$$y emp$oye'&p to %o&t 36V
T"e m%in %'#%nt%ge %re re'&+e'
m%inten%n+e %n' impro#e en#ironment%$!rien'$ineT"e m%in 'i%'#%nt%ge i eniti#ity to
p%rti%$ 'i+"%rge (P2)P%rti%$ 'i+"%rge %re $o+%$ie' re%'o*nP2 +%&e inter1t&rn "ort1+ir+&it
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PARTIAL DISCHAR0ES IN DR3
T3PE TRANSFOR2ERS
4e%&re %'opte' %g%int P2Poiti#e Temper%t&re oe!!i+ient !&e
%re integr%te' in LV +oi$ !or temper%t&re
rie ign%$$ing;e o! P2 $o+%tor
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PO/ER S3STE2 DISTUR-ANCES
Voltage dips
Definition momentary reduction in rms
voltages
Single voltage dip
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PO/ER S3STE2 DISTUR-ANCES
Multiple voltage dip
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PO/ER S3STE2 DISTUR-ANCES
Multiple voltage dip
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PO/ER S3STE2 DISTUR-ANCES
An actual voltage dip captured by a power quality analyser
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PO/ER S3STE2 DISTUR-ANCES
Causes - Local and remote faults inductive
loading switc! on of large loads
"ffects - #ripping of sensitive equipment
resetting of control systems motor stalling$tripping
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PO/ER S3STE2 DISTUR-ANCES
Voltage surge$spi%es
Definition momentary rise in rms
voltages
&rofile of voltage surge
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PO/ER S3STE2 DISTUR-ANCES
Causes capacitor switc!ing switc! off of
large loads p!ase faults
"ffects tripping of sensitive equipment
damage to insulation and windingsdamage to power supplies for electronic
equipment
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PO/ER S3STE2 DISTUR-ANCES
'vervoltage
Definition An increase in rms voltage for several
seconds
Causes Load switc!ing capacitor switc!ing
system voltage regulation
"ffects dielectric brea%down degradation of
equipment Long interruptions disturbances in
control systems and low current communication
circuits "lectrodynamic and t!ermal stress(
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PO/ER S3STE2 DISTUR-ANCES
)ndervoltage
Definition A reduction in rms voltage for
several seconds or minutes
Causes *eavy networ% loading Loss ofgeneration poor power factor lac% of
var support
"ffects reduced lig!t output dielectric
equipment over!eating and eventual tripping
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PO/ER S3STE2 DISTUR-ANCES
Supply interruptions
Definition Loss of power supply
Causes &ower system faults equipment failures
control malfunctions C+ tripping
"ffects loss of supply to customers
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PO/ER S3STE2 DISTUR-ANCES
Voltage fluctuations
Definition momentary rise and fall of supply
voltage
Causes arc and induction furnaces rolling mills
mine winders resistance welders etc(
"ffects flic%er in incandescent lamps andflourescent lamps
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PO/ER S3STE2 DISTUR-ANCES
,requency variations
Definition c!anges in supply frequency
Causes fault or maladusted governors serious
over or under loading
"ffects irregular output of motor drives tripping of
generators and !eating in transformer core
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PO/ER S3STE2 DISTUR-ANCES
#ransients
Definition Sub-cycle disturbance wit! a fast voltage
c!ange
Causes line faults control and protection malfunctionslig!tning stri%es switc! of capacitor ban%s
"ffects control system resetting damage to sensitive
electronic components
damage to insulation
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PO/ER S3STE2 DISTUR-ANCES
*armonic
Definition A component of a periodic wave
!aving a frequency t!at is an integral
multiple of t!e fundamental power linefrequency
A distorted supply waveform
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PO/ER S3STE2 DISTUR-ANCES
Causes non-linear loads .personal computers
electronic ballasts rectifiers . supplies )&S
units disc!arge lig!ting/ adustable speed
motor drives ferromagnetic devices Dc motor
drives electric disc!arge lamps and arcing
equipment e(g( arc furnace and arc welders(
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PO/ER S3STE2 DISTUR-ANCES
*armonic current flow
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PO/ER S3STE2 DISTUR-ANCES
"ffects
o 0ncreased losses in customer and utility power
system components(
o#ransformers may !ave to be derated
oLoads wit! !ig!ly distorted current waveforms
also !ave a very poor power factoro'ver!eating and mec!anical oscillations in
motor-load systems
o0ncreased current increased !eating dielectric stress and potential failure of
capacitor ban%s(
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PO/ER S3STE2 DISTUR-ANCES
"ffects
o,alse or spurious operations and trips damaging
or rupturing of components in fuses and circuit
brea%ers
o)tility meters may record measurements
incorrectly resulting in !ig!er billings to
consumers(
oComputers and communication equipment may
e1perience interferences and failures(
oConductor over!eating(
RE2EDIAL 2EASURES FOR PO/ER
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RE2EDIAL 2EASURES FOR PO/ER
S3STE2 DISTUR-ANCES
)&S system
Composition energy storage device rectifier
inverter transfer switc!es etc
#ypes on-line and off-line
RE2EDIAL 2EASURES FOR PO/ER
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RE2EDIAL 2EASURES FOR PO/ER
S3STE2 DISTUR-ANCES ,ilters
S!unt connected
"liminate !armonics
Can be passive or active
Large space is required for passive filters
&ossible resonance effect
RE2EDIAL 2EASURES FOR PO/ER
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RE2EDIAL 2EASURES FOR PO/ER
S3STE2 DISTUR-ANCES
Static Var Compensators
A s!unt-connected assembly of capacitors and inductors
Dynamic voltage restorers
A voltage stource converter
"nergy storage system
Connected in series
0nects voltages
RE2EDIAL 2EASURES FOR PO/ER
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RE2EDIAL 2EASURES FOR PO/ER
S3STE2 DISTUR-ANCES
0nection transformer
RE2EDIAL 2EASURES FOR PO/ER
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RE2EDIAL 2EASURES FOR PO/ER
S3STE2 DISTUR-ANCES
Ferro1reon%nt tr%n!ormer 2uns !ig!ly saturated
Stored magnetic energy maintains voltage during volt dip disturbance
condition
Voltage surges do not proceed to secondary circuit
SUR0ES IN TRANS2ISSION LINES
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SUR0ES IN TRANS2ISSION LINES
DUE TO LI0HTNIN0
Lig!tning is a disc!arge of stored electricity in t!e clouds
Magnetic obects radioactive substances !ig! mountains tall beings
pointed c!urc! spires etc are prone to lig!tning
A lowered field intensity is required in t!e presence of moisture in order to
lig!tning to stri%e
#ypes of lig!tning stro%es3 Stepped leader return stro%e and dart leaderstro%e
SUR0ES IN TRANS2ISSION LINES
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SUR0ES IN TRANS2ISSION LINES
DUE TO LI0HTNIN0
4ays in w!ic! lig!tning affects transmission lines
Direct stro%e
0ndirect stro%e
&ropagation of lig!tning on transmission lines
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SUR0ES IN TRANS2ISSION LINES
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#ypical t5$t6 4ays in w!ic! lig!tning affects transmission
lines
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SUR0ES IN TRANS2ISSION LINES
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"ffects on lig!tning on power systems
+rea%down of insulators
,las!over of insulators
"quipment damage
Surge impedances
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SUR0ES IN TRANS2ISSION LINES
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2eflection and transmission of surges
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2emedial measures against lig!tning
S!ielding by eart! wires
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SUR0ES IN TRANS2ISSION LINES
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Surge modifiers
Connected in series
#!ey absorb some of t!e surge energy and flatten t!e wavefront
"1amples are cables arcing ground suppressers eart!ing coils .peterson
coils/ and water-et resistances
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SUR0ES IN TRANS2ISSION LINES
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Surge diverters Connected in parallel
#!ey divert surges to eart!
&rincipal types are !orn-gap arresters sp!ere-gap arresters rod-gap arresters pellet
arresters t!yrite arrestor
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SUR0ES IN TRANS2ISSION LINES
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&rinciple of operation of gap arresters
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SUR0ES IN TRANS2ISSION LINES
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&ellet arrestors Arrestor switc! is made up of pellets of brown lead pero1ide w!ic! are coated wit! lit!arge
.lead mono1ide/
Lit!arge is punctured under surge conditions allowing t!e lead pero1ide to divert surge to
ground
#!e !ig! current density c!anges t!e lead pero1ide at t!e punctured area to lit!arge t!us
!ealing t!e puncture
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SUR0ES IN TRANS2ISSION LINES
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#!yrite arrestors Made of a stac% of dis%s and an air gap
Dis% offers low resistance to !ig! voltages and !ig! resistance to low voltages
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SUR0ES IN TRANS2ISSION LINES
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0deal electrical c!aracteristics of an ideal surge diverter0t s!ould not absorb any current during normal operation or s!ould possess very !ig!
impedance
During overvoltage surges it s!ould brea% down easily to provide low resistance pat! to
eart!
#!e disc!arge current during brea%down s!ould not be e1cessive so as to damage t!e
surge diverter
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SU 0 S S SS O S
DUE TO LI0HTNIN0
#!e normal frequency current after t!e brea%down s!ould beinterrupted as soon as t!e transient voltage !as fallen below t!e
brea%down value
UN-ALANCE
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UN-ALANCE
2e!inition- )nbalance is a system condition w!ere t!ree-p!ase voltages andcurrents !ave different magnitudes and t!e angular displacement between
p!ases is not 567 degrees%&e untransposed lines distributed generation unsymmetrical faults and
single p!ase loading
UN-ALANCE
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UN-ALANCE@&%nti!i+%tion o! &n%$%n+e)nbalance is quantified using symmetrical components
45665
7
=
V
Vu
v
4566sc
L
v
S
Su
UN-ALANCE
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UN-ALANCE
Limit !or ;n%$%n+e for LV and MV systems for 57-minutes intervals
for *V systems for 57-minute intervals
45665
7
= I
I
uI
47
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EFFECTS OF UN-ALANCE
0nduction mac!ines-
Mac!ine cannot produce full torque due to bra%ing torque from
negative sequence component
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EFFECTS OF UN-ALANCE
0nduction mac!ines - cont.
+earings may suffer mec!anical damage because of induced torque
components at double system frequency
"1cessive !eating in stator and rotor caused by fast rotating inverse
magnetic field
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EFFECTS OF UN-ALANCE
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UN-ALANCE
T"ree1*in'ing tr%n!ormer
2ITI0ATIN0 THE EFFECTS OF
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UN-ALANCEOt"er !&n+tion o! T"ree1*in'ing tr%n!ormer
#o supply p!ase-compensating devices t!at may be connected for purposes of power
factor correction or voltage regulation
#o provide voltage for au1iliary power purposes in a substation or to supply a local
distribution system
#o supply split-winding generators
2ITI0ATIN0 THE EFFECTS OF
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UN-ALANCE0n a star-star or star-8ig8ag transformer a delta connected tertiary winding
reduces t!e 8ero-p!ase sequence impedance and allows adequate eart! fault
current to flow for t!e operation of protective gear
Sometimes Delta-connected tertiary windings are put on 9-p!ase ban%s to
provide a circuit for t!e t!ird !armonic of t!e e1citing current
#o reduce t!ird-!armonic voltage components
2ITI0ATIN0 THE EFFECTS OF
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UN-ALANCE
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UN-ALANCE
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UN-ALANCE
2ITI0ATIN0 THE EFFECTS OF
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UN-ALANCE
Po*er e$e+troni+ 'e#i+e
+e!ave as if t!ey were rapidly c!anging complementary
impedances compensating for c!anges in impedance of
t!e loads on eac! p!ase(
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HI0H VOLTA0E TEST E1UIP2ENT
Po*er !re/&en+y "ig" #o$t%ge gener%torCascade arrangement of transformers
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HI0H VOLTA0E TEST E1UIP2ENT
Po*er !re/&en+y "ig" #o$t%ge gener%tor2esonant transformer
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HI0H VOLTA0E TEST E1UIP2ENT
Hig" !re/&en+y "ig" #o$t%ge gener%tor#esla coil
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HI0H VOLTA0E TEST E1UIP2ENT
Hig" !re/&en+y "ig" #o$t%ge gener%tor #esla coil
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HI0H VOLTA0E TEST E1UIP2ENT
Hig" 'ire+t #o$t%ge gener%tor Re+ti!ier +ir+&it
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DIRECT VOLTA0E 0ENERATORS
Vo$t%ge 'o&$er +ir+&it
DIRECT VOLTA0E 0ENERATORS
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E$e+trot%ti+ gener%torc!arge is placed on a carrier eit!er insulating or an isolatedconductor and raised to t!e required potential by being
mec!anically moved t!roug! t!e electrostatic field(
DIRECT VOLTA0E 0ENERATORS
I2PULSE VOLTA0E 0ENERATOR
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+asic operating principle
I2PULSE VOLTA0E 0ENERATOR
I2PULSE VOLTA0E 0ENERATOR
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)ncontrolled operation
I2PULSE VOLTA0E 0ENERATOR
I2PULSE VOLTA0E 0ENERATOR
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C!arging and disc!arging waveform ofuncontrolled operation
I2PULSE VOLTA0E 0ENERATOR
I2PULSE VOLTA0E 0ENERATOR
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Controlled operation
I2PULSE VOLTA0E 0ENERATOR
I2PULSE VOLTA0E 0ENERATOR
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C!arging and disc!arging waveform ofcontrolled operation
I2PULSE VOLTA0E 0ENERATOR
I2PULSE VOLTA0E 0ENERATOR
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4&$ti1t%ge imp&$e gener%tor,or larger impulse voltages from small si8ed
transformers
Several capacitors connected in parallel for
c!argingCapacitors disc!arge in series
I2PULSE VOLTA0E 0ENERATOR