St-Petersburg, Florida - May 8 2003 1
PRACTICAL CONSIDERATIONS PRACTICAL CONSIDERATIONS FOR CONTROLLED SWITCHINGFOR CONTROLLED SWITCHINGOFOF POWERPOWER TRANSFORMERSTRANSFORMERS
Esteban Portales Yvon FilionAndré Mercier
Seminar / Workshop on Controlled SwitchingSeminar / Workshop on Controlled Switching
Possible Benefits for Transformers Applications
St-
Pet
ersb
urg,
Flo
rida
-M
ay 8
200
32
Tra
nsf
orm
ers
Tra
nsf
orm
ers
Co
ntr
olle
dC
on
tro
lled
Sw
itch
ing
Sw
itch
ing
: P
rog
ram
me
: P
rog
ram
me
1.In
tro
du
ctio
n2.
Tra
nsf
orm
er e
ner
giz
atio
nan
d r
esu
ltin
g T
emp
ora
ry
Ove
rvo
ltag
es(T
OV
s)3.
Mit
igat
ion
mea
ns
4.R
easo
ns
for
usi
ng
CS
S o
n t
ran
sfo
rmer
s5.
Exa
mp
les
of
case
s w
her
e C
SS
can
ad
van
tag
eou
sly
be
use
d:
a)In
tegr
atio
n of
pow
er p
lant
b)
Sys
tem
res
torin
gc)
Ene
rgiz
atio
nof
tran
sfor
mer
nea
r se
nsib
le e
quip
men
td)
Rep
lace
men
t or
com
plet
e re
furb
ishm
ent o
f CB
6.O
pti
mal
clo
sin
g s
trat
egy
a)Im
port
ance
of t
he r
esid
ual f
lux
b)S
witc
hing
alg
orith
mc)
Sim
ulat
ions
with
Con
trol
led
Sw
itchi
ng s
olut
ion
d)M
eans
for
mea
surin
g th
e re
sidu
al fl
ux7.
Mea
ns
for
mea
suri
ng
th
e re
sid
ual
flu
x8.
Co
ncl
usi
on
s9.
Ref
eren
ces
St-
Pet
ersb
urg,
Flo
rida
-M
ay 8
200
33
1: In
tro
du
ctio
n1:
Intr
od
uct
ion
Tra
nsfo
rmer
ene
rgiz
atio
npr
oduc
esan
inru
shcu
rren
twho
sem
agni
tude
dep
ends
on th
etr
ansf
orm
er c
hara
cter
istic
s, th
epo
int o
n w
ave
clos
ing
time
and
resi
dual
flux.
Inru
shcu
rren
thas
a ric
hha
rmon
icco
nten
t, am
ong
whi
ch2n
d , 3
rd, 4
thha
rmon
ics
are
the
mos
tim
port
ant.
Inru
shcu
rren
thar
mon
ics
may
caus
e te
mpo
rary
over
volta
ges
on th
esy
stem
due
to r
eson
ance
prev
ailin
gun
der
som
eop
erat
ing
cond
ition
s.
St-
Pet
ersb
urg,
Flo
rida
-M
ay 8
200
34
2:
2: T
rans
form
er
Tra
nsfo
rmer
ene
rgiz
atio
nen
ergi
zatio
nan
dan
dre
sulti
ngre
sulti
ngT
OV
sT
OV
s
Bec
ause
gen
erat
edte
mpo
rary
-ove
rvol
tage
son
th
esy
stem
attr
ansf
orm
er e
nerg
izat
ion
depe
ndon
: Net
wor
k co
nfig
urat
ion
Ope
ratin
gco
nditi
onT
rans
form
er c
hara
cter
istic
sC
ircui
t bre
aker
char
acte
ristic
sE
tc.
Eac
hca
se h
asto
be
stud
ied
clos
ely
(sim
ulat
ions
per
form
ed, e
tc.)
in o
rder
to s
elec
t th
erig
htso
lutio
n an
dto
spe
cify
the
right
char
acte
ristic
sfo
r as
soci
ated
equi
pmen
ts
St-
Pet
ersb
urg,
Flo
rida
-M
ay 8
200
35
2:
2: T
rans
form
er
Tra
nsfo
rmer
ene
rgiz
atio
nen
ergi
zatio
nan
dan
dre
sulti
ngre
sulti
ngT
OV
sT
OV
s–– e
xam
ple
exam
ple
--
Net
wor
k T
OV
prod
uced
atth
een
ergi
zatio
nof
a 3
15-1
61 k
V
tran
sfor
mer
from
315
kV
wit
ho
ut
con
tro
lled
sw
itch
ing
St-
Pet
ersb
urg,
Flo
rida
-M
ay 8
200
36
2:
2: T
rans
form
er
Tra
nsfo
rmer
ene
rgiz
atio
nen
ergi
zatio
nan
dan
dre
sulti
ngre
sulti
ngT
OV
sT
OV
s––
exam
ple
exam
ple
--
Inru
shcu
rren
tpro
duce
dat
the
ener
giza
tion
of a
315
-161
kV
tr
ansf
orm
er fr
om 3
15 k
V w
ith
ou
tco
ntr
olle
d s
wit
chin
g
St-
Pet
ersb
urg,
Flo
rida
-M
ay 8
200
37
3: M
itig
atio
n m
ean
s 3:
Mit
igat
ion
mea
ns
--R
easo
ns fo
r us
ing
them
to r
educ
e th
e ov
ervo
ltage
s(T
OV
) re
sulti
ng
from
the
ener
giza
tion
of la
rge
pow
er
tran
sfor
mer
s [1
], [2
], [3
].to
red
uce
the
mec
hani
cal a
nd e
lect
rical
st
ress
es o
n X
FO
S in
ord
er to
incr
ease
thei
r re
mai
ning
life
[4],
[5]
St-
Pet
ersb
urg,
Flo
rida
-M
ay 8
200
38
3: M
itig
atio
n m
ean
s 3:
Mit
igat
ion
mea
ns
––lis
t o
f p
oss
ible
so
luti
on
slis
t o
f p
oss
ible
so
luti
on
s
Use
of p
re-in
sert
ion
resi
stor
s
Use
of c
ontr
olle
d sw
itchi
ng s
yste
m (
CS
S)
Gen
erat
orvo
ltage
ram
ping
rest
orat
ion
proc
edur
e;E
nerg
izat
ion
oftr
ansf
orm
ers
unde
rlo
adon
the
sub-
tran
smis
sion
sid
e(if
pos
sibl
e).
App
ly r
estr
ictio
ns o
n th
e op
erat
ing
cond
ition
s (le
ss
flexi
bilit
y fo
r th
e op
erat
ors,
may
be
criti
cal f
or s
yste
m r
esto
ring
scen
ario
s)
St-
Pet
ersb
urg,
Flo
rida
-M
ay 8
200
39
3: M
itig
atio
n m
ean
s 3:
Mit
igat
ion
mea
ns
––p
rep
re-- i
nse
rtio
n r
esis
tors
in
sert
ion
res
isto
rs --
Inse
rer
les
resu
ltat
sd
e si
mu
lati
on
ave
c 8
et 1
4 m
s
St-
Pet
ersb
urg,
Flo
rida
-M
ay 8
200
310
4: U
se
4: U
se o
fo
fC
SS
C
SS
wit
hw
ith
op
tim
al
op
tim
al c
losi
ng
clo
sin
gst
rate
gy
stra
teg
y
A.
Impo
rtan
ce o
f the
res
idua
l flu
x
B.
Sw
itchi
ng a
lgor
ithm
C.
Sim
ulat
ions
with
Con
trol
led
Sw
itchi
ng
solu
tion
D.
Mea
ns fo
r m
easu
ring
the
resi
dual
flux
St-
Pet
ersb
urg,
Flo
rida
-M
ay 8
200
311
4: a
) Im
po
rtan
ce o
f 4:
a)
Imp
ort
ance
of
the
the
resi
du
alre
sid
ual
flu
xfl
ux
Opt
imal
clo
sing
str
ateg
y fo
r 3-
phas
e tr
ansf
orm
ers
equi
pped
with
a s
econ
dary
or
tert
iary
del
ta w
indi
ng w
as
foun
d to
be
first
clo
sing
the
phas
e ha
ving
the
high
est
resi
dual
flux
, and
then
clo
sing
the
two
rem
aini
ng p
hase
s si
mul
tane
ousl
y:
For
the
first
pha
se to
clo
se, t
he o
ptim
al c
losi
ng ti
me
is
dete
rmin
ed b
y th
e re
sidu
al fl
ux r
elat
ive
to th
e in
stan
tane
ous
volta
ge;
Clo
sing
tim
e of
the
two
othe
r ph
ases
is o
ptim
al u
pon
zero
cr
ossi
ng o
f the
vol
tage
indu
ced
onto
thes
e ph
ases
.
St-
Pet
ersb
urg,
Flo
rida
-M
ay 8
200
312
4: a
)… Im
po
rtan
ce
4: a
)… Im
po
rtan
ce o
fo
fth
eth
ere
sid
ual
resi
du
alfl
ux
flu
x
Acc
urat
ekn
owle
dge
ofth
ere
sidu
alflu
x (m
agni
tude
and
pola
rity
on e
ach
phas
e) o
fthe
tran
sfor
mer
sto
be
switc
hed-
inis
a ke
ypa
ram
eter
allo
win
gto
det
erm
ine
the
best
stra
tegy
for
min
imiz
ing
the
inru
shcu
rren
tand
thus
limit
syst
emov
ervo
ltage
san
dtr
ansf
orm
er s
tres
ses.
St-
Pet
ersb
urg,
Flo
rida
-M
ay 8
200
313
4: b
) S
wit
chin
g A
lgo
rith
m4:
b)
Sw
itch
ing
Alg
ori
thm
The
firs
t clo
sing
inst
ant i
s se
t whe
n th
e in
stan
tane
ous
volta
ge is
equ
al to
:
()
αsi
n*
32
*
=V
v
=ω
αϕ
*2
*3
*ar
ccos
Vr
St-
Pet
ersb
urg,
Flo
rida
-M
ay 8
200
314
4:
4: b
) b
) ……
Sw
itch
ing
Alg
ori
thm
Sw
itch
ing
Alg
ori
thm
Gra
ph
ical
exa
mp
le o
f th
e al
go
rith
m a
pp
licat
ion
Gra
ph
ical
exa
mp
le o
f th
e al
go
rith
m a
pp
licat
ion
P
has
e B
P
has
e A
P
has
e C
St-
Pet
ersb
urg,
Flo
rida
-M
ay 8
200
315
5.
5. P
ract
ical
cas
es w
her
e C
SS
can
ad
van
tag
eou
sly
be
use
d.
Pra
ctic
al c
ases
wh
ere
CS
S c
an a
dva
nta
geo
usl
y b
e u
sed
.
5.1
Inte
gra
tio
n o
f p
ow
er p
lan
t
5.1.
1 E
ner
giz
ing
at
pow
er p
lan
t S
/S
5.1.
2 E
ner
giz
ing
at
inte
gra
tin
g S
/S
5.2
Sys
tem
res
tori
ng
5.3
En
erg
izat
ion
of
tran
sfo
rmer
nea
r eq
uip
men
t se
nsi
ble
to
sy
stem
dis
turb
ance
s
St-
Pet
ersb
urg,
Flo
rida
-M
ay 8
200
316
5.1
Inte
gra
tio
n o
f p
ow
er p
lan
t5.
1 In
teg
rati
on
of
po
wer
pla
nt
Pow
er p
lant
sub
stat
ion
Inte
grat
ing
subs
tatio
n
St-
Pet
ersb
urg,
Flo
rida
-M
ay 8
200
317
5.1.
15.
1.1
En
erg
izin
g o
f tr
ansf
orm
er a
tE
ner
giz
ing
of
tran
sfo
rmer
at
po
wer
po
wer
pla
nt
s/s
pla
nt
s/s
Pow
er p
lant
su
bsta
tion
Inte
grat
ing
subs
tatio
n
St-
Pet
ersb
urg,
Flo
rida
-M
ay 8
200
318
5.1.
15.
1.1
En
erg
izin
g o
f tr
ansf
orm
er a
tE
ner
giz
ing
of
tran
sfo
rmer
at
po
wer
po
wer
pla
nt
s/s
pla
nt
s/s
(( Nex
tN
ext ))
Tem
po
rary
ove
rvo
ltag
es(t
ov)
wer
e o
bse
rved
wh
en
ener
giz
ing
th
e st
ep-u
p t
ran
sfo
rmer
s lo
cate
d a
t th
e p
ow
er p
lan
t su
bst
atio
n (
refe
r to
fig
. 1)
Pro
tect
ion
sys
tem
s m
ay o
per
ate
un
der
su
ch v
olt
age
dis
turb
ance
s, p
oss
ible
dam
ages
fo
r th
e eq
uip
men
t
Fo
r th
e ca
ses
wh
ere
imp
ort
ant
TO
Vs
are
ob
serv
ed, i
t is
nec
essa
ry t
o r
edu
ce o
verv
olt
ages
usi
ng
co
ntr
olle
d
swit
chin
g o
r p
re-i
nse
rtio
n r
esis
tors
.
St-
Pet
ersb
urg,
Flo
rida
-M
ay 8
200
319
Exa
mp
le o
f E
xam
ple
of
TO
Vs
TO
Vs
ob
serv
ed in
th
e p
ow
er p
lan
t o
bse
rved
in t
he
po
wer
pla
nt
s/s
s/s
du
rin
g
du
rin
g e
ner
giz
atio
nen
erg
izat
ion
of
of
tran
sfo
rmer
at
the
Po
wer
pla
nt
S/S
wit
ho
ut
any
mit
igat
ion
mea
ns
tran
sfo
rmer
at
the
Po
wer
pla
nt
S/S
wit
ho
ut
any
mit
igat
ion
mea
ns
Fig
1 -
TO
Vs
and
inru
sh c
urre
nts
obse
rved
whe
n en
ergi
zatio
nta
kes
plac
e at
pow
er p
lant
S/S
St-
Pet
ersb
urg,
Flo
rida
-M
ay 8
200
320
PPra
ctic
alra
ctic
alca
se 1
: ca
se 1
: E
ner
giz
ing
En
erg
izin
gp
ow
erp
ow
ertr
ansf
orm
ers
tran
sfo
rmer
satat
SM
S
M --
3 (
3 ( w
ith
wit
hco
ntr
olle
dco
ntr
olle
dsw
itch
ing
swit
chin
g))
4:
4: c
) c)
Sim
ula
tio
ns
wit
h C
on
tro
lled
Sw
itch
ing
so
luti
on
St-
Pet
ersb
urg,
Flo
rida
-M
ay 8
200
321
5.1.
25.
1.2
En
erg
izat
ion
En
erg
izat
ion
at r
emo
te
at r
emo
te s
/ss/
s(p
arti
cula
r o
per
atin
g
(par
ticu
lar
op
erat
ing
con
dit
ion
s w
hen
po
wer
pla
nt
is is
lan
ded
on
th
e ra
dia
l su
bco
nd
itio
ns
wh
en p
ow
er p
lan
t is
isla
nd
ed o
n t
he
rad
ial s
ub
-- tra
nsm
issi
on
sys
tem
)tr
ansm
issi
on
sys
tem
)
St-
Pet
ersb
urg,
Flo
rida
-M
ay 8
200
322
5.1.
2 S
itu
atio
n
5.1.
2 S
itu
atio
n a
tatth
eth
ere
mo
tere
mo
tes/
ss/
s
Ove
rvo
ltag
esd
ue
to t
ran
sfo
rmer
en
erg
izat
ion
atre
mo
tes/
s w
ith
the
po
wer
pla
nt
isla
nd
edo
n
the
sub
tran
smis
sio
nsy
stem
may
lead
to e
ven
hig
her
ove
rvo
ltag
es. (
refe
rto
fig
. 2)
solu
tio
ns
con
tem
pla
ted
to m
itig
ate
ove
rvo
ltag
es:
Pre
-in
sert
ion
resi
sto
rso
n b
reak
ers;
Co
ntr
olle
dsw
itch
ing
wit
hso
me
adap
tio
ns
for
this
par
ticu
lar
app
licat
ion
;G
ener
ato
rvo
ltag
e ra
mp
ing
rest
ora
tio
np
roce
du
re;
En
erg
izat
ion
of
tran
sfo
rmer
su
nd
erlo
ado
n
the
sub
tran
smis
sio
nsi
de.
St-
Pet
ersb
urg,
Flo
rida
-M
ay 8
200
323
5.1.
25.
1.2
En
erg
izat
ion
En
erg
izat
ion
atatre
mo
tere
mo
tes/
s (w
/o
s/s
(w/o
an
yan
ym
itig
atio
n
mit
igat
ion
mea
ns
mea
ns
)) Fig
2 -
TO
Vs
and
inru
sh c
urre
nts
obse
rved
whw
nen
ergi
zatio
nta
kes
plac
e at
inte
grat
ing
S/S
St-
Pet
ersb
urg,
Flo
rida
-M
ay 8
200
324
5.2
5.2
Sys
tem
res
tori
ng
Sys
tem
res
tori
ng
735
kV s
yste
m
1 . S
tart
gen
erat
or
grou
ps
2. E
nerg
ize
Xfo
at
inte
grat
ing
S/S
Inte
grat
ing
S/S
Pow
er p
lant
S/S
Pow
er p
lant
S/S
St-
Pet
ersb
urg,
Flo
rida
-M
ay 8
200
325
5.2
Sys
tem
res
tori
ng
5.
2 S
yste
m r
esto
rin
g --
resu
lts
resu
lts
Sim
ilar
case
as
for
ener
gizi
ng a
t rem
ote
S/S
Can
res
ult i
n ve
ry im
port
ant T
OV
s
Can
cau
se d
amag
e to
equ
ipm
ent
St-
Pet
ersb
urg,
Flo
rida
-M
ay 8
200
326
5.2)
Sys
tem
res
tori
ng
5.
2) S
yste
m r
esto
rin
g ––
ano
ther
sce
nar
io
ano
ther
sce
nar
io --
St-
Pet
ersb
urg,
Flo
rida
-M
ay 8
200
327
5.2
5.2
Sys
tem
res
tori
ng
exa
mp
le w
ith
2 G
rou
ps
Sys
tem
res
tori
ng
exa
mp
le w
ith
2 G
rou
ps
--1
Lin
e1
Lin
e
St-
Pet
ersb
urg,
Flo
rida
-M
ay 8
200
328
Pra
ctic
alP
ract
ical
case
2:
case
2:
Sw
Sw
.. --in
at
315
kV:
2Gro
up
sin
at
315
kV:
2Gro
up
s-- 1
Lin
e w
ith
1L
ine
wit
h c
sscss
5: S
yste
m r
esto
rin
g
5: S
yste
m r
esto
rin
g --
Sim
ula
tio
ns
wit
h C
on
tro
lled
Sw
itch
ing
so
luti
on
St-
Pet
ersb
urg,
Flo
rida
-M
ay 8
200
329
5.3
En
erg
izat
ion
of
tran
sfo
rmer
nea
r eq
uip
men
t
sen
sib
le t
o s
yste
m d
istu
rban
ces
Ene
rgiz
ing
one
of th
ese
xfo
w/o
mit
igat
ion
mea
n m
ay c
ause
som
e co
mm
utat
ion
fail
ure
of H
VD
C
conv
erte
r
Isla
nded
net
wor
k
St-
Pet
ersb
urg,
Flo
rida
-M
ay 8
200
330
6:
6:
Mea
suri
ng
th
e re
sid
ual
flu
xM
easu
rin
g t
he
resi
du
al f
lux
The
ory
Sen
sors
Rea
l cas
e m
easu
rem
ent
St-
Pet
ersb
urg,
Flo
rida
-M
ay 8
200
331
6:
6: m
easu
rin
g t
he
resi
du
al f
lux:
th
eory
mea
suri
ng
th
e re
sid
ual
flu
x: t
heo
ry
To
achi
eve
the
mag
netic
flu
x “Φ
”m
easu
rem
ent
with
out
bein
g in
trus
ive,
the
val
ue h
as t
o be
der
ived
fro
m a
mor
e co
mm
on (
or e
asily
acc
essi
ble)
sig
nal:
the
volta
ge “
E”
at t
he
tran
sfor
mer
inpu
t. .
rE
Nϕ
+
∫=
Φ1
Mea
suri
ng a
nd i
nteg
ratin
g th
e vo
ltage
of
each
pha
se j
ust
befo
re
and
duri
ng d
e-en
ergi
zatio
nof
the
tra
nsfo
rmer
in
the
stea
dy s
tate
de
term
ines
th
e re
sidu
al
flux
, w
hich
is
th
e en
d va
lue
of
the
inte
grat
ed v
olta
ge.
Whe
n an
eve
nt o
ccur
s, a
tim
e w
indo
w i
s se
t (j
ust
befo
re a
nd d
urin
g de
-ene
rgiz
atio
nof
the
tra
nsfo
rmer
) an
d th
e in
tegr
atio
n of
the
vo
ltage
sig
nal o
f ea
ch p
hase
of
the
unlo
aded
tran
sfor
mer
is p
erfo
rmed
. Wit
h th
is m
etho
d, o
nly
a sm
all n
umbe
r of
cyc
les
is u
sed
for
inte
grat
ion
to p
reve
nt th
at e
ven
a sm
all o
ffse
t err
or in
the
volt
age
mea
sure
men
t lea
d to
a la
rge
erro
r in
the
resu
lts.
St-
Pet
ersb
urg,
Flo
rida
-M
ay 8
200
332
6: M
6: M
easu
rin
g t
he
resi
du
al f
lux:
sen
sors
easu
rin
g t
he
resi
du
al f
lux:
sen
sors
For
an
accu
rate
mag
netic
flux
mea
sure
men
t, th
e sy
stem
nee
ds3
mai
n ite
ms:
Tra
nsfo
rmer
vol
tage
mea
sure
men
t
Mea
sure
men
tof t
he tr
ansf
orm
erin
put c
urre
nt
and
a so
ftwar
e pa
ckag
e
St-
Pet
ersb
urg,
Flo
rida
-M
ay 8
200
333
Tra
nsfo
rmer
vol
tage
mea
sure
men
t
6: M
6: M
easu
rin
g t
he
resi
du
al f
lux:
sen
sors
easu
rin
g t
he
resi
du
al f
lux:
sen
sors
St-
Pet
ersb
urg,
Flo
rida
-M
ay 8
200
334
Tra
nsfo
rmer
vol
tage
mea
sure
men
t …
6: M
6: M
easu
rin
g t
he
resi
du
al f
lux:
sen
sors
easu
rin
g t
he
resi
du
al f
lux:
sen
sors
St-
Pet
ersb
urg,
Flo
rida
-M
ay 8
200
335
Acc
ura
tem
easu
rem
ent
of
the
tran
sfo
rmer
inp
ut
curr
ent ra
ng
ing
fro
m t
he
very
low
mag
net
izin
g
curr
ent
up
to
th
e h
igh
inru
sh c
urr
ent
valu
es
6: M
6: M
easu
rin
g t
he
resi
du
al f
lux:
sen
sors
easu
rin
g t
he
resi
du
al f
lux:
sen
sors
St-
Pet
ersb
urg,
Flo
rida
-M
ay 8
200
336
Tra
nsf
orm
er in
pu
t cu
rren
t …
6: M
6: M
easu
rin
g t
he
resi
du
al f
lux:
sen
sors
easu
rin
g t
he
resi
du
al f
lux:
sen
sors
St-
Pet
ersb
urg,
Flo
rida
-M
ay 8
200
337
Sof
twar
e pa
ckag
e
6: M
6: M
easu
rin
g t
he
resi
du
al f
lux:
sen
sors
easu
rin
g t
he
resi
du
al f
lux:
sen
sors
St-
Pet
ersb
urg,
Flo
rida
-M
ay 8
200
338
For
inte
grat
ing
the
new
Sai
nte-
Mar
guer
ite-3
hy
droe
lect
ric p
ower
hous
e (S
M-3
) in
Tra
nsÉ
nerg
ie’s
315-
kV g
rid, t
he fo
llow
ing
chal
leng
es w
ere
succ
essf
ully
ov
erco
me:
Ext
ensi
veE
MT
P s
imul
atio
n st
udie
s
Dev
elop
men
tof v
olta
ge a
ndcu
rren
tsen
sors
Dev
elop
men
tand
inst
alla
tion
of 2
pro
toty
pes
Pre
limin
ary
test
s
6: M
6: M
easu
rin
g t
he
resi
du
al f
lux:
rea
l cas
eea
suri
ng
th
e re
sid
ual
flu
x: r
eal c
ase
St-
Pet
ersb
urg,
Flo
rida
-M
ay 8
200
339
6.6.M
easu
rin
g t
he
resi
du
al f
lux:
rea
l cas
eM
easu
rin
g t
he
resi
du
al f
lux:
rea
l cas
e
Mea
sure
d/c
alcu
late
dre
sid
ual
flu
x af
ter
swit
chin
g-o
ut
the
tran
sfo
rmer
St-
Pet
ersb
urg,
Flo
rida
-M
ay 8
200
340
6. M
6. M
easu
rin
g t
he
resi
du
al f
lux:
rea
l cas
eea
suri
ng
th
e re
sid
ual
flu
x: r
eal c
ase
Mea
sure
dM
easu
red
curr
ent
curr
ent
atatth
eth
etr
ansf
orm
er
tran
sfo
rmer
en
erg
izat
ion
ener
giz
atio
n
St-
Pet
ersb
urg,
Flo
rida
-M
ay 8
200
341
6. M
easu
rin
g t
he
resi
du
al f
lux:
rea
l cas
e6.
Mea
suri
ng
th
e re
sid
ual
flu
x: r
eal c
ase
Mea
sure
dM
easu
red
net
wo
rk v
olt
age
net
wo
rk v
olt
age
atatth
eth
etr
ansf
orm
er
tran
sfo
rmer
en
erg
izat
ion
ener
giz
atio
n
St-
Pet
ersb
urg,
Flo
rida
-M
ay 8
200
342
7.7.E
con
om
ical
co
nsi
der
atio
ns
Eco
no
mic
al c
on
sid
erat
ion
s
Lis
t o
f p
oin
ts t
o b
e co
nsi
der
ed
Co
st a
nal
ysis
(P
IR r
epla
cem
ent
vsC
SS
)M
ain
ten
ance
co
sts
(fre
qu
ent
swit
chin
g)
Tec
hn
ical
fea
sib
ility
of
CS
S w
ith
exi
stin
g C
B
char
acte
rist
ics
(RD
DS
, tim
e sc
atte
rin
g,)
Rel
iab
ility
issu
e an
d c
on
seq
uen
ces
for
un
avai
lab
ility
of
the
equ
ipm
ent
St-
Pet
ersb
urg,
Flo
rida
-M
ay 8
200
343
8. C
on
clu
sio
ns
8. C
on
clu
sio
ns
Ene
rgiz
atio
nof
pow
ertr
ansf
orm
er c
anre
sult
in s
ever
eT
OV
son
the
syst
emm
ainl
yde
pend
ing
on:
The
syst
emco
nditi
ons
Tra
nsfo
rmer
cha
ract
eris
tics
Inst
ant o
fene
rgiz
ing
on th
epo
int o
n w
ave
in r
elat
ion
with
the
resi
dual
flux.
Sys
tem
sim
ulat
ion
stud
ies
are
nece
ssar
yto
eva
luat
eth
eris
kof
havi
ngT
OV
sfo
llow
ing
XF
oen
ergi
zatio
n
For
the
case
s w
ithT
OV
s, m
itiga
tion
mea
nsar
e ne
eded
to
avoi
dda
mm
ages
to e
quip
men
t.
St-
Pet
ersb
urg,
Flo
rida
-M
ay 8
200
344
8. C
on
clu
sio
ns
…8.
Co
ncl
usi
on
s …
Labo
rato
ry te
sts
and
on-s
ite te
sts
conf
irmed
the
accu
racy
of
res
idua
l flu
x m
easu
rem
ent.
An
optim
al c
losi
ngst
rate
gyw
asva
lidat
edfo
r 3-
phas
e tr
ansf
orm
ers
havi
nga
seco
ndar
yor
tert
iary
delta
con
nect
edw
indi
ng.
Acc
urat
e re
sidu
al fl
ux m
easu
rem
ent e
nabl
es e
nerg
izat
ion
of u
nloa
ded
tran
sfor
mer
s w
ithou
t gen
erat
ing
inru
sh
curr
ent o
r T
OV
on
any
phas
e.
Con
trol
led
switc
hing
of t
rans
form
ers
isfe
asib
le,
relia
ble,
co
st-e
ffect
ive
and
less
str
essf
ul fo
r th
e tr
ansf
orm
er a
nd th
e el
ectr
ical
net
wor
k.
St-
Pet
ersb
urg,
Flo
rida
-M
ay 8
200
345
1: …
Ref
eren
ces
1: …
Ref
eren
ces
Hyd
ro Q
uéb
ec S
imu
lati
on
stu
die
s
Oth
er r
efer
ence
s1)
CIG
RE
WG
13.0
7, C
on
tro
lled
Sw
itch
ing
of
HV
AC
Cir
cuit
Bre
aker
s –
Gu
ide
for
app
licat
ion
, Par
t 1:
EL
EC
TR
A, N
o 1
83, A
pri
l 199
9, p
p 4
3-73
. Par
t 2:
EL
EC
TR
A,
No
185
, Au
gu
st 1
999,
pp
37-
57
2) C
IGR
E W
G 1
3.07
, Co
ntr
olle
d S
wit
chin
g o
f H
VA
C C
ircu
it B
reak
ers
–P
lan
nin
g, S
pec
ific
atio
n a
nd
Tes
tin
g o
f co
ntr
olle
d s
wit
chin
g s
yste
ms,
E
LE
CT
RA
, No
197
, Au
gu
st 2
001
3) C
IGR
E 2
002,
rep
ort
12-
116,
«A
nal
ysis
, sim
ula
tio
n a
nd
tes
tin
g o
f tr
ansf
orm
er in
sula
tio
n f
ailu
res
rela
ted
to
sw
itch
ing
tra
nsi
ents
ove
rvo
ltag
es»
4) IE
EE
, Tra
nsa
ctio
ns
on
po
wer
del
iver
y,M
. Ste
ure
r, K
. Frö
hlic
h, “
Th
e im
pac
t o
f in
rush
cu
rren
ts o
n t
he
mec
han
ical
str
ess
of
hig
h v
olt
age
po
wer
tra
nsf
orm
er
coils
”
St-
Pet
ersb
urg,
Flo
rida
-M
ay 8
200
346
1: …
Ref
eren
ces
??
??
?1:
… R
efer
ence
s ?
??
??
«W
orld
wid
e m
any
tran
sfor
mer
insu
latio
n fa
ilure
s ha
vebe
en r
epor
ted
caus
ed b
y sw
itchi
ng o
pera
tions
, whi
leth
ose
tran
sfor
mer
s ha
d pr
evio
usly
pas
sed
all t
hest
anda
rd te
sts
and
com
plie
d to
all
qual
ity
requ
irem
ents
.»
«T
he p
robl
em is
gen
eral
ly a
ssoc
iate
d to
the
high
freq
uenc
yov
ervo
ltage
spr
oduc
ed b
y th
e re
-str
ikes
and
pre-
strik
es d
urin
g th
e op
enin
g or
clo
sin
gof
a s
witc
hing
devi
ce.»
St-
Pet
ersb
urg,
Flo
rida
-M
ay 8
200
347
1: …
Ref
eren
ces
1: …
Ref
eren
ces
«F
rom
failu
reex
per
ien
ceo
n p
ow
er t
ran
sfo
rmer
sve
ryo
ften
itw
assu
spec
ted
that
inru
shcu
rren
ts,
occ
urr
ing
wh
enen
erg
izin
gu
nlo
aded
tran
sfo
rmer
s, w
her
ere
aso
nfo
r d
amag
e.»
«A
lth
ou
gh
inru
sh c
urr
ents
no
rmal
ly a
re s
mal
ler
the
forc
es c
anh
ave
sim
ilar
amp
litu
des
as
tho
se a
t sh
ort
cir
cuit
ho
wev
erw
ith
lon
ger
exp
osu
re
tim
e.»
St-
Pet
ersb
urg,
Flo
rida
-M
ay 8
200
348
Th
ank
you
for
you
rat
ten
tio
n
Sem
inar
/ W
ork
shop o
n C
ontr
olled S
witchin
gSem
inar
/ W
ork
shop o
n C
ontr
olled S
witchin
g
Possib
le B
enefits
for
Tra
nsfo
rmers
Applications
