Internati
o
nal Journal
of App
lied Power E
n
gineering
(IJAPE)
V
o
l.
3, N
o
. 1
,
A
p
r
il
201
4, p
p
.
23
~32
I
S
SN
: 225
2-8
7
9
2
23
Jo
urn
a
l
h
o
me
pa
ge
: h
ttp
://iaesjo
u
r
na
l.com/
o
n
lin
e/ind
e
x.ph
p
/
IJAPE
Remediation of Old Subst
a
ti
ons for Arc Flash Hazard
Z
a
kir Husain
,
Deep
ak
Ku
m
a
r,
Khu
s
hbu
Thakur
Departem
ent
of
Ele
c
tri
cal
Eng
i
n
eering
,
Na
tiona
l
Institute
of
Te
ch
nolog
y, Ham
i
rp
ur, HP, Ind
i
a
Article Info
A
B
STRAC
T
Article histo
r
y:
Received
Ja
n 11, 2014
Rev
i
sed
Feb
21
, 20
14
Accepte
d
Mar 8, 2014
Arc Flash is mu
ch differ
e
nt fro
m the
conventio
nal shock hazard
in the sens
e
that it doesn’t
involve dir
ect contac
t of human beings with the live or
energized part.
The arcing ener
g
y
involv
e
s high temperature o
f
up to or
bey
ond
20000K. This pap
e
r pres
ents a
case
stud
y of arc flash h
a
zard an
aly
s
is
carried out in older industrial plant a
nd the techn
o
logical and wor
k
procedure
changes
that
c
a
n
be
incorpor
ated
to r
e
duc
e th
e
in
ciden
t
en
erg
y
le
vel
and thus
provide
a saf
e
r
environment for
the working
pers
onnels in
plan
t.
Keyword:
Fl
ash P
r
ot
ect
i
on B
o
u
n
d
ary
Inci
dent
E
n
e
r
g
y
PCC
R
e
l
a
y
coor
di
na
t
i
o
n
Copyright ©
201
4 Institut
e
o
f
Ad
vanced
Engin
eer
ing and S
c
i
e
nce.
All rights re
se
rve
d
.
Co
rresp
ond
i
ng
Autho
r
:
1.
INTRODUCTION
Arc Flas
h Haz
a
rd eve
n
after
extensi
v
e study re
m
a
in
s an unex
p
l
o
re
d area
i
n
m
o
st
of t
h
e subst
a
t
i
o
ns
i
n
In
di
a as t
h
e
swi
t
c
hgea
r
s u
s
ed are al
m
o
st 30 y
ears ol
d wi
t
h
p
r
ot
ect
i
o
n sy
st
em
desi
gned t
o
a
d
d
r
ess
sho
r
t
-
circu
it fau
lt isolatio
n
.
Thu
s
arc flash
h
azard
l
e
v
e
ls for th
ese
ex
istin
g
su
bstatio
n
s
is q
u
ite hig
h
allo
wi
n
g
al
m
o
st
n
o
work
t
o
b
e
d
o
n
e
in
liv
e pan
e
ls ev
en
with
PPEs
o
f
20
cal/c
m
2
. Ho
wev
e
r for m
a
in
ten
a
n
ce activ
ities in
th
e
vi
ci
ni
t
y
of
l
i
v
e areas a
n
d f
o
r
o
n
l
i
n
e c
o
n
d
i
t
i
on m
oni
t
o
r
i
ng t
e
c
hni
que
s
l
i
k
e t
h
e
r
m
ogr
aphy
t
h
e S
w
i
t
c
hgea
r
Pan
e
ls are to
be op
en
ed
and
th
eir th
erm
a
l i
m
ag
in
g
is
t
o
b
e
t
a
ken i
n
t
h
ei
r
l
i
v
e co
n
d
i
t
i
on
t
hus m
a
ki
ng
i
t
uns
afe
fo
r t
h
e o
p
e
r
at
o
r
s. I
n
or
der t
o
m
i
ti
gat
e
t
h
i
s
pr
obl
em
,
certain changes ca
n be
m
a
de in these
existing s
w
itchgears
as well as in
Pro
t
ection
settin
g
s
to
m
a
k
e
th
em safer for human
o
p
e
ratio
ns an
d
also
th
e
co
st in
vo
lv
ed
can
be
ju
st
i
f
i
e
d
wi
t
h
t
h
e sa
vi
n
g
s i
n
c
o
st
by
av
oi
di
n
g
fai
l
u
re a
n
d c
ons
eq
ue
nt
dam
a
ge.
There a
r
e seve
ral
m
e
thods s
u
gge
sted till now to carry
out
the arc flash ca
lculation [1]-[4]. Howeve
r,
IEEE
m
e
t
hod
base
d
on
e
xpe
ri
m
e
nt
al
resul
t
s
an
d em
pi
ri
cal
fo
rm
ul
as der
i
ved
t
h
erei
n a
r
e f
o
u
n
d
t
o
be
m
o
st
accurate
First step is t
o
carry
out a
r
c fl
ash
hazard a
n
a
l
ysis
of the e
x
i
s
ting s
w
itchge
a
r s
o
that the
problem
areas
can
b
e
id
en
tifi
e
d
an
d im
p
r
o
v
e
m
en
ts o
r
ch
ang
e
s can
t
h
en b
e
sug
g
ested
as
per feasib
ility.
2.
AR
C
FL
AS
H HAZ
A
R
D
AN
ALYS
IS
In orde
r to ca
rry out the arc flas
h hazard
analysis, first of all da
ta collection is the single m
o
st
i
m
p
o
r
tan
t
and cu
m
b
erso
m
e
task
wh
ich
tak
e
s a lo
t o
f
time an
d
if
m
a
in
tain
ed
pro
p
e
rly can
lead
to
easy
i
n
co
rp
orat
i
o
n f
o
r f
u
t
u
re cha
n
g
e
s. In a
n
ol
d
In
dust
r
i
a
l
subst
a
t
i
on/
pl
a
n
t
,
t
h
e a
r
c fl
ash a
n
al
y
s
i
s
can be car
ri
ed o
u
t
in
th
e
fo
llo
wi
ng
step
wise m
a
n
n
e
r so
as
n
o
t
t
o
m
i
ss an
yth
i
ng
:
The
w
hol
e
pl
a
n
t
/
s
u
b
st
at
i
on
s
h
o
u
l
d
be
di
vi
d
e
d i
n
t
o
sect
i
o
n
s
o
r
ar
eas.
I
n
d
i
vi
dual
w
o
r
k
i
n
g
pers
o
nnel
m
o
st
fam
i
l
i
a
r sho
u
l
d
be
gi
v
e
n a
r
eas t
o
ga
t
h
er
dat
a
f
o
r
all equipm
ents in that
pa
rticular a
r
ea s
o
t
h
at
no
equi
pm
ent
i
s
m
i
ssed out
.
Whi
l
e
carry
i
n
g out
t
h
i
s
su
r
v
e
y
, t
h
e equi
pm
ent
s
sh
oul
d al
so be l
a
bel
e
d by
t
h
ei
r
Evaluation Warning : The document was created with Spire.PDF for Python.
I
S
SN
:
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252
-87
92
IJA
P
E Vol
.
3
,
No
. 1, A
p
ri
l
20
14
:
23
–
3
2
24
vol
t
a
ge
a
n
d
s
o
urce
fee
d
,
i
f
n
o
t
al
rea
d
y
do
n
e
. A
s
p
rea
d
s
h
e
e
t
sh
oul
d
be
m
a
de an
d
f
o
l
l
o
wi
ng
d
a
t
a
s
h
oul
d
be
cap
tured in
t
h
at.
a.
Gene
rato
r
i.
R
a
t
i
ng (M
V
A
)
ii.
Sub-tra
n
sie
n
t reactance
iii.
Bus to which c
o
nnected
b.
Transform
e
r
i.
R
a
t
i
ng (M
V
A
)
ii.
Vo
ltag
e
Ratio
iii.
Perce
n
t
a
ge i
m
peda
nce
iv
.
Bu
s to and
from
c.
Transm
ission Line
i.
Length (km
)
ii.
Ty
pe of
C
o
nd
u
c
t
o
r
iii.
Im
pedance (
Ω
/k
m)
iv
.
Nu
m
b
er
o
f
lin
es in
p
a
rallel
d.
Mo
to
r
i.
R
a
t
i
ng (
k
W)
ii.
Ty
pe of
m
o
t
o
r
iii.
Ratio
o
f
starting
cu
rren
t t
o
rated
cu
rren
t
e.
Cab
l
e
i.
Size of ca
ble
ii.
Mater
i
al
iii.
Mak
e
iv
.
Ratin
g
(A)
v.
Length of
cabl
e
vi
.
N
u
m
b
er
o
f
runs
v
ii.
Bu
s to and
from
f.
Relay
i.
Type (Electromechanica
l/Solid state/Num
e
rical)
ii.
Settin
g
rang
e
iii.
Setting (PSM,
TMS/Set
curre
nt,
tim
e)
g.
CT
i.
Ratio
ii.
Seco
nda
ry
rat
i
ng
h.
Breake
r
i.
Breaking ca
pa
city
ii.
Trip
un
its,
if an
y
i.
Bu
s
i.
Nam
e
s
ii.
kV
Le
vel
iii.
Design
Fau
lt
with
stan
d lev
e
ls
iv
.
Co
ndu
cto
r
g
a
ps
v.
Sw
itchg
ear type (
B
ox
or
O
p
en
)
The
data ca
ptured a
b
ove ca
n be
use
d
to prepare
an
up
dated
sing
le lin
e
d
i
agram
in
co
rp
orating
th
e
rat
i
ngs
of e
qui
pm
ent
and t
h
e rel
a
y
set
t
i
ngs. Al
so,
vari
ou
s
co
nf
igu
r
ation
s
of
op
er
ation
of
Pow
e
r
system
sh
ou
l
d
be m
e
nt
i
oned
on t
h
e
SLD
(S
i
ngl
e Li
ne Di
a
g
ram
)
i
ndi
cat
i
ng t
h
e st
at
u
s
o
f
brea
ke
rs, t
r
a
n
sf
orm
e
rs et
c. du
ri
n
g
t
h
ese c
o
n
f
i
g
ura
t
i
ons.
Se
parat
e
SLDs
can
be
m
a
de
fo
r t
h
i
s
p
u
r
pos
e.
There
s
h
o
u
l
d
b
e
a l
i
s
t
i
ng
o
f
j
obs
bei
n
g ca
rri
ed
out
i
n
pl
ant
at
va
ri
o
u
s t
i
m
es i
n
cl
u
d
i
n
g a
n
y
swi
t
c
hi
n
g
ope
rat
i
o
ns, m
a
i
n
t
e
nanc
e
jo
bs,
t
e
st
i
ng et
c.
The l
i
s
t
i
ng sh
o
u
l
d
al
so i
n
cl
ud
e t
h
e nat
u
r
e
of
jo
b i
.
e. w
h
et
h
e
r i
t
i
s
t
o
be done
onl
i
n
e/
of
fl
i
n
e. M
o
st
o
f
th
e job
s
to
b
e
carried ou
t in
a sub
s
tatio
n
can
be don
e in
de-en
e
rg
ized
state th
u
s
m
a
k
i
n
g
th
e job
safe fo
r t
h
e
wo
rk
ers.
Fo
r f
u
rt
her i
n
s
u
ranc
e of safet
y
f
o
r
suc
h
ki
n
d
o
f
j
o
bs,
pri
o
r t
o
car
ry
i
ng
out
t
h
e
j
o
b
,
t
h
e de
-e
ner
g
i
z
e
d
state sh
ou
ld
be co
nfirm
e
d
by a tested
v
o
l
t
a
g
e
d
e
tect
or.
Th
is will avo
i
d
hu
m
a
n
erro
rs lik
e work
ing o
n
t
h
e
neighboring c
o
m
p
artm
ent, any brea
ke
r accidentally rem
a
inin
g close
d
etc.
Also the
voltage detector s
h
ould be
t
e
st
ed near
an
y
l
i
v
e equi
pm
ent
eve
r
y
t
i
m
e
i
t
i
s
bei
ng
us
ed t
o
e
n
s
u
re i
t
doe
s n
o
t
gi
ve
err
one
o
u
s i
n
d
i
cat
i
on.
Pr
op
er
g
r
ou
ndin
g
shou
ld
b
e
pr
ov
id
ed
no
t
b
y
insu
lation
st
i
c
k
but
by
fi
xe
d cl
i
p
s
t
o
ens
u
re t
h
e sy
s
t
em
i
s
gr
o
u
n
d
e
d
whi
l
e carry
i
ng
out
t
h
e jo
b. T
h
e rem
oval
of
g
r
ou
n
d
i
n
g sh
oul
d be ens
u
red
bef
o
re
rest
o
r
at
i
on o
f
supply (t
o
be i
n
corporated i
n
check s
h
eet).
Evaluation Warning : The document was created with Spire.PDF for Python.
I
J
APE
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:
225
2-8
7
9
2
Reme
di
at
i
o
n
of
Ol
d
S
u
b
st
at
i
o
ns f
o
r Arc
Fl
as
h
Haz
a
r
d
(
Z
aki
r
H
u
s
a
i
n
)
25
Thu
s
, Job
s
to
b
e
don
e in
liv
e state are v
e
ry li
mite
d
.
Ou
t of th
ese, th
e remo
te op
eration
an
d
rem
o
te
racki
n
g of
breakers
can further re
du
ce t
h
e ex
po
su
r
e
lev
e
l of
wo
rk
er
s.
The
rem
o
t
e
o
p
erat
i
o
n c
a
n
be
i
m
p
l
e
m
en
ted
by
m
a
k
i
n
g
simp
le ch
ang
e
s in th
e co
n
t
ro
l ci
rcu
it of t
h
e equ
i
p
m
en
t wh
ile it is tak
e
n
out for
main
ten
a
n
ce. Re
m
o
te
rack
i
n
g, wh
ile n
o
t
always
ph
ys
i
cally p
o
ssib
l
e in
ex
istin
g
plan
ts, can
always b
e
considere
d
a
pos
sibility and retrof
itting fe
asibility shoul
d be c
h
ecke
d
. Such J
o
bs re
qui
re ba
re m
i
nim
u
m
change
to t
h
e
existing equipm
ent and a
r
e
m
o
st econom
i
cal. They
should
be ide
n
tifie
d
from
the list of
jobs
and
cha
n
ges s
h
oul
d
be
pl
an
ne
d i
n
a
pha
se
wi
se m
a
nner
du
ri
ng
t
h
ei
r
sche
d
u
l
ed o
u
t
a
ge
.
Fig.
1.
Re
m
o
te Power Rack
ing
Un
it
On
ly tho
s
e jobs sho
u
l
d
b
e
h
i
g
h
ligh
t
ed
wh
ich
canno
t b
e
do
n
e
i
n
d
e
-en
e
rg
ized
co
nd
ition
.
Th
e fau
lt
lev
e
ls at th
ese
j
o
b
l
o
cation
s
sh
ou
ld be calculated
b
y
ca
rry
i
n
g
o
u
t
Sh
ort
ci
rcui
t
st
udy
.
It
sho
u
l
d
be asce
rt
ai
ne
d
that the Buses/
cables/Breake
r
s/CT s
econ
d
a
r
y
are desi
gne
d
fo
r wi
t
h
st
an
di
ng t
h
ese f
a
ul
t
l
e
vel
s
as i
n
a
n
y
ol
d
sub
s
t
a
t
i
on m
a
ny
l
o
ads are a
dde
d l
a
t
e
r o
n
or t
h
e
buse
s
are ext
e
n
d
e
d
w
i
t
hout
pay
i
n
g
m
u
ch at
t
e
nt
i
on t
o
t
h
e
d
e
sign
with
stan
d fau
lt lev
e
ls. Relay co
ord
i
natio
n
for t
h
e ex
istin
g relay settin
g
s
sh
ou
ld
b
e
co
nfirm
e
d
b
e
fo
re
carrying
arc flash
an
alysis.
Any ad
ju
stm
e
n
t
s in
relay se
ttin
g
s
, if
requ
ired
, sho
u
l
d
b
e
m
a
d
e
at th
is po
in
t.
Th
e ar
c
f
a
u
lt cu
rr
en
t
lev
e
ls sh
ou
ld
b
e
calculated
at th
e iden
tif
ied
jo
b locatio
n
s
as
p
e
r
I
EEE 1584.
Th
e tim
e o
f
o
p
eratio
n as
p
e
r th
e
relay settin
gs fo
r t
h
e arc
fau
lt curren
t
sh
ou
ld
b
e
d
e
term
i
n
ed.
The i
n
ci
dent
e
n
er
gy
an
d
fl
ash p
r
ot
ect
i
on
b
o
u
n
d
a
r
y
can
the
n
be
calculated by the em
pirical equations
gi
ve
n
by
IE
EE
15
8
4
a
n
d
t
h
e a
r
eas
wi
t
h
e
n
er
g
y
lev
e
ls >
1
.
2
cal/c
m
2
are to
be id
en
tified
.
At th
is
po
in
t, t
h
e id
en
tified lo
catio
ns
with
i
n
cid
e
nt
e
n
er
gy
l
e
vel
s
>
1.
2 c
a
l
/
c
m
2
sho
u
l
d
be c
h
eck
e
d
for th
ese
p
o
i
n
t
s, if app
licab
le, to
b
r
i
n
g down
th
e en
erg
y
lev
e
ls:
1.
Wh
ile carrying
ou
t an
y swit
ch
ing
action
s
t
h
ere
s
hou
ld
b
e
well do
cu
m
e
n
t
ed
proce
d
ure
s
/
checksheets
marking e
v
en the s
w
itch a
n
d
com
p
artm
en
t nu
m
b
er
to
avo
i
d hu
m
a
n
m
i
stak
es.
2.
During
m
a
in
te
n
a
n
ce
of a break
e
r if
an
y ch
eck
on
liv
e
bu
s bar is to
b
e
m
a
d
e
to
ch
eck
p
itti
n
g
, it sho
u
l
d
be
mad
e
b
y
two-prong
ed shu
tter
lifter m
a
d
e
o
f
i
n
su
lat
o
r.
3.
Onl
y
Trai
ne
d
Pers
on
nel
s
sh
o
u
l
d
be al
l
o
we
d fo
r suc
h
j
o
b
s
i
n
prese
n
ce of a st
and
b
y
p
e
rso
n
t
o
av
oi
d
err
o
rs
. Pe
rs
on
n
e
l
s
sh
oul
d
be
g
i
ven l
i
v
e
d
e
m
o
o
n
s
p
are
o
n
de
com
m
i
ssi
oned
equi
pm
ent
.
4.
Prov
ision
o
f
viewin
g
wi
n
dow with
b
e
tter
emissiv
ity
for job
s
lik
e therm
o
g
r
aph
y
so
th
at t
h
e
p
a
nel
co
m
p
art
m
en
t is no
t requ
ired
t
o
b
e
o
p
e
n
e
d
5.
Prov
ision
o
f
Main
ten
a
n
c
e b
y
p
a
ss switch
to
in
co
rp
o
r
ate an
altern
at
e set o
f
relay settin
g
s
fo
r
in
stan
tan
e
ou
s
o
p
e
ration
of
relay in
th
e even
t of fau
lt wh
ile wo
rk
ing
o
n
t
h
e system
.
Th
ese settings
shoul
d
be
normalized after t
h
e
job is
finis
h
ed.
6.
Retro
f
ittin
g to
arc resistan
t switch
g
e
ars i
n
sp
ecific
p
r
o
b
l
ematic areas.
7.
Use of
Categ
o
r
y
II
I or IV
m
u
ltim
e
ter.
8.
If t
h
ere i
s
a l
o
ad m
i
xup
of a
r
eas i
n
M
C
C
s
, t
h
i
s
shoul
d be
rect
i
f
i
e
d i
n
an
y
schedul
e
d
o
u
t
a
ge so t
h
at
i
t
doe
s not
ca
use heart
b
u
r
n
.
9.
Pro
v
i
s
i
o
n
o
f
f
u
sed i
n
com
i
ng a
n
d
cha
n
ge
fuse
s o
f
no
rm
al
t
y
p
e
wi
t
h
c
u
rre
nt
l
i
m
i
t
i
ng t
y
pe
(c
l
a
ss R
K
1
)
.
10
.
In ea
rl
i
e
r
desi
gns
t
h
e
LV m
o
t
o
rs are
p
r
ovi
ded
wi
t
h
on
ly sh
ort-circu
it
(cleared
by fuse
s) a
n
d therm
a
l
pr
ot
ect
i
on
(cl
eared
by
co
nt
act
or)
.
Whi
l
e
fo
r
faul
t
s
i
n
v
o
l
v
i
ng t
w
o
pha
ses
and si
ngl
e-
p
h
a
se gr
o
u
n
d
, t
h
e
fu
se will tak
e
a lo
t of tim
e fo
r clearing
t
h
e fau
lt. Th
u
s
t
h
e
co
st vs b
e
n
e
fit for
p
r
o
v
i
d
i
ng
ad
d
ition
a
l relay
pr
ot
ect
i
on
o
n
hi
g
h
rat
i
n
g m
o
t
o
rs f
o
r
fast
i
s
ol
at
i
on s
h
o
u
l
d
be ca
ref
u
l
l
y
consi
d
ere
d
.
F
o
r t
h
i
s
, t
h
e L
V
Evaluation Warning : The document was created with Spire.PDF for Python.
I
S
SN
:
2
252
-87
92
IJA
P
E Vol
.
3
,
No
. 1, A
p
ri
l
20
14
:
23
–
3
2
26
cont
act
o
r
s b
r
ea
ki
n
g
capaci
t
y
in case of fa
ul
t
s
sho
u
l
d
be c
h
e
c
ked
.
Ot
he
r So
l
u
t
i
ons - Tem
pora
r
y
R
e
duce
d
Set
t
i
ngs,
A
r
c
Sensi
n
g
R
e
l
a
y
s
, Z
one
Sel
ect
i
v
e I
n
t
e
rl
ocki
n
g
,
A
r
c C
ont
ai
nm
ent
Devi
ce
an
d
PPEs
.
T
h
e
te
m
p
o
r
ary redu
ced
setting
s
o
f
relay requ
i
r
es sp
ecific cap
a
b
l
e trip
sy
ste
m
s an
d
d
o
es n
o
t
p
r
ov
ide
pr
ot
ect
i
on i
f
t
h
e event
d
o
es n
o
t
occ
u
r
d
u
ri
n
g
t
h
e
pl
an
ne
d
act
i
v
i
t
y
. The pr
o
v
i
s
i
on
o
f
l
i
ght
se
ns
ors al
o
n
g
wi
t
h
cu
rre
nt
i
n
put
f
r
o
m
C
T
and Z
o
ne sel
ect
i
v
e i
n
t
e
rl
oc
ki
n
g
can al
s
o
be
u
s
ed f
o
r i
n
st
ant
a
neo
u
s t
r
i
ppi
n
g
purpose
for t
h
e arc fa
ult. Howeve
r for hi
gher
haza
rd
ris
k
category jobs
eve
n
the
3-c
y
cle time to be
taken by breaker to clear the fault will not be accep
table.
Thus in suc
h
cases, arc containm
ent device
can be used
.
T
h
e
l
a
st
l
i
n
e of
defe
nse
ca
n be
PPE
t
o
be use
d
whi
l
e
wo
rki
n
g
.
I
n
m
a
rket
as
o
f
no
w
e
v
e
n
40cal/cm
2
suits are a
v
ailable. But these s
u
it
s are
ve
ry
b
u
l
ky an
d
m
a
y lea
d
to
d
i
fficu
lty in
carryin
g ou
t
th
e jo
b. Thu
s
, after redu
cing
th
e en
erg
y
levels as
m
u
ch as
pos
si
bl
e by
ot
her m
eans as d
e
scri
be
d ab
o
v
e
,
t
h
e PPE s
h
oul
d
be ch
ose
n
.
Aft
e
r t
h
i
s
, as
per
The Na
ti
onal E
l
ectrical Code (NEC
), Section 110.16, a Arc
Flash Hazard Warning
la
bel
shoul
d
be
placed
on the e
qui
pm
ent to
warn the
qual
ified pers
ons
of
pote
n
tial electric arc haza
rds
.
It shoul
d
be placed so a
s
to
be clearly visi
ble, s
h
ould i
n
c
l
ude the Haza
rd
ri
sk cat
eg
o
r
y
,
fl
ash
pr
ot
ect
i
o
n b
o
u
n
d
ary
a
n
d rec
o
m
m
ended PPE
s re
qui
r
e
d i
f
w
o
rk i
s
t
o
be
do
ne i
n
norm
al working
distance.
He
re for study a
sam
p
le
sin
g
l
e lin
e d
i
agram
is
tak
e
n wh
ere th
e
b
o
lted fau
l
t
l
e
vel
s
an
d
pr
ot
ect
i
v
e de
vi
ce r
a
t
i
ngs a
r
e cal
c
u
l
a
t
e
d
fo
r
di
ff
e
r
ent
p
o
ssi
bl
e c
o
n
f
i
g
urat
i
o
ns
f
o
r
o
p
erat
i
n
g t
h
e
Po
wer Sy
st
em
. Ot
her S
o
l
u
t
i
ons
- Tem
pora
r
y
R
e
duce
d
Se
t
t
i
ngs, A
r
c Se
nsi
n
g R
e
l
a
y
s
, Zo
ne Sel
ect
i
v
e
In
terl
o
c
k
i
n
g
,
Arc C
o
n
t
ain
m
en
t Dev
i
ce and
PPEs.
Th
e t
e
m
p
o
r
ary reduced
setting
s
of relay requ
ires
specific capabl
e
trip system
s
and
do
es n
o
t
pr
o
v
i
d
e
pr
ot
ect
i
on i
f
t
h
e e
v
e
n
t
d
o
es
not
oc
cur
d
u
ri
n
g
t
h
e
pl
an
ned act
i
v
i
t
y
.
The p
r
ovi
si
on
of l
i
g
ht
se
n
s
ors al
on
g
wi
t
h
cu
rre
nt
i
n
put
fr
om
C
T
and Zo
ne sel
ect
i
v
e
i
n
t
e
rl
oc
ki
n
g
ca
n al
s
o
be
used
fo
r i
n
st
ant
a
ne
o
u
s t
r
i
ppi
ng
p
u
r
pos
e f
o
r t
h
e
ar
c fa
ul
t
.
Howe
ver for
highe
r hazard ri
sk category jobs eve
n
th
e 3-cycle tim
e
to be take
n by bre
a
ker to clear
the fault will not
be accepta
ble. Thus
in such case
s
, arc
containm
ent device ca
n be
use
d
. The last line of
defe
nse ca
n be
PPE t
o
be
use
d
w
h
i
l
e
wo
r
k
i
n
g
.
I
n
m
a
rk
et as of
now eve
n
40cal/cm
2
s
u
its are availa
ble. But
these s
u
its are
very
bul
ky and m
a
y lead to difficulty in
carr
yin
g
ou
t th
e
jo
b. Th
us, af
ter r
e
du
ci
n
g
t
h
e en
erg
y
l
e
vel
s
as m
u
ch as p
o
ssi
bl
e
by
ot
he
r m
eans as desc
ri
be
d ab
ove
, t
h
e
PPE s
h
o
u
l
d
be c
h
ose
n
.
Aft
e
r
t
h
i
s
, a
s
p
e
r
The Nati
onal
Electrical Code (NEC
), Secti
on
110.16, a
Arc Flash
Hazard
W
a
rni
ng la
bel should
be pl
aced on
th
e equ
i
p
m
en
t to
warn
t
h
e qualified
p
e
rson
s o
f
p
o
t
en
tial el
ectric arc haza
rds
.
It s
h
ould
be place
d s
o
a
s
to be
clearly visible, should incl
ude th
e Hazard risk category, flash protec
tion bounda
ry and recomm
ended PPEs
req
u
i
r
e
d
i
f
w
o
rk i
s
t
o
be
do
ne i
n
n
o
rm
al
wo
rki
n
g di
st
an
ce. Here
fo
r st
udy
a sam
p
l
e
si
ngl
e l
i
n
e di
a
g
ram
i
s
t
a
ken w
h
er
e t
h
e b
o
l
t
e
d faul
t
l
e
vel
s
and pr
ot
ect
i
v
e de
v
i
ce rat
i
ngs ar
e cal
cul
a
t
e
d for di
ffe
rent
p
o
ssi
bl
e
con
f
i
g
urat
i
o
ns
fo
r
ope
rat
i
n
g t
h
e P
o
wer
Sy
st
em
.
3.
SAMPLE SYSTEM FAULT CAL
CULATION
Th
e
Sing
le Line d
i
agram
fo
r th
e sam
p
le syste
m
is as shown b
e
low:
Fig.
2.
i
ngl
e Li
ne
Di
agram
of a
Sam
p
l
e
sy
st
em
Evaluation Warning : The document was created with Spire.PDF for Python.
I
J
APE
I
S
SN
:
225
2-8
7
9
2
Reme
di
at
i
o
n
of
Ol
d
S
u
b
st
at
i
o
ns f
o
r Arc
Fl
as
h
Haz
a
r
d
(
Z
aki
r
H
u
s
a
i
n
)
27
The Sam
p
l
e
syst
em
consi
s
t
s
of a
pl
ant
havi
ng C
a
pt
i
v
e Po
wer
Generat
i
o
n o
f
31.
5M
V
A
i
n
o
r
de
r t
o
sel
f-sust
a
i
n
t
h
e pl
ant
al
ong
wi
t
h
ru
nni
n
g
i
t
i
n
paral
l
e
l
wi
t
h
t
h
e gri
d
f
o
r i
m
proved
rel
i
a
bi
l
i
t
y
.
The Power from
grid is being r
eceived by
the plant at 33kV level
and then is being step down to
11
kV,
6.
6kV
a
nd
41
5V
fo
r su
bseque
nt
di
st
ri
but
i
on t
o
l
o
a
d
s.
At each distribution level there ar
e 2 transformers each individually
capable of feeding the load. The
extra capacity
is provid
ed
fo
r f
u
ture usa
g
e.
Now s
hort
ci
rcui
t
st
udy
i
s
carri
ed out
on t
h
e gi
ven sy
st
em
t
o
cal
cul
a
t
e
bol
t
e
d faul
t
curre
nt
l
e
vel
s
.
Here, Differe
n
t
operating configu
r
ati
ons and t
h
ei
r im
pact
on B
o
l
t
e
d faul
t
current
and arc fl
ash l
e
vel
s
i
s
considered. The different
case
s
considere
d
are:
Case 1: T1, T3, T5 in line
Case 2: T1, T3,
T4, T
5
, T6 in line
Case 3: T1, T2,
T3, T
5
in line
Case 4
:
All Tran
sform
e
rs in
l
i
n
e
Thus
bol
t
e
d fa
ul
t
current
l
e
vel
s
of t
h
e buses
are as gi
ven i
n
Tabl
e I. Here
B
u
s 1 i
s
not
co
nsi
d
ered as i
t
is d
i
rectl
y
co
n
n
ected
to
th
e g
r
id
and
an
y wo
rk o
n
it will b
e
do
n
e
after
d
i
scon
n
ectin
g
fro
m
t
h
e g
r
id.
TABLE I.
F
AULT
C
URRENT
W
HEN
S
YST
E
M
R
UNN
ING
I
N
P
ARAL
LE
L
W
ITH
G
RID
Bus Na
m
e
Voltage
level (kV
)
Bolted F
a
ult
Curre
n
t (kA
)
Case 1
Case 2
Case 3
Case 4
Bus 2
11
16.
87
22.
47
Bus
3
6.
6
10.
93 15.
2 11.
42
16.
5
PCC
0.
415
28.
9
54.
32
29.
39
56.
02
As can
b
e
seen
th
e fau
lt
lev
e
l
s
v
a
ry wid
e
ly
with
di
fferent
operat
i
ng co
nfi
gurat
i
ons an
d al
so wi
t
h
t
h
e
rat
i
ng of
di
ffe
r
e
nt
equi
pm
ent
l
i
k
e t
r
ansform
e
r, ge
nerat
o
r
c
h
osen
du
ri
ng sy
st
em
desi
gn. The l
east
faul
t
l
e
vel
of
syste
m
is
th
ere wh
en
o
n
l
y o
n
e tran
sfo
r
m
e
r
i
s
o
p
e
rated
.
Bu
t th
is wi
ll
d
ecrease th
e re
liab
i
l
ity
o
f
th
e s
y
ste
m
a
s
th
is tran
sfo
r
m
e
r failu
re can lead
to
co
m
p
le
te
lo
ss of
p
o
wer. Fu
rth
e
r ev
en
with
on
e tran
sfo
r
m
e
r o
p
e
ratio
n
t
h
e
fau
lt cu
rren
t
lev
e
ls will ch
an
ge with
syste
m
o
p
e
ratio
n in
p
a
rallel with
g
r
id
o
r
in iso
l
ated
co
nd
itio
n
(as sho
w
n i
n
Table II).
C
a
se 5:
Isol
at
ed + T3,
T5 i
n
l
i
ne
Case 6
:
Iso
l
ate
d
+ All Tran
sformers in
lin
e
TABLE II.
FAUL
T CURRE
N
T
WHE
N
SY
STE
M
RUN
N
IN
G I
N
I
S
OLA
TED
COND
ITI
O
N
Bus Na
m
e
Voltage
leve
l
(kV
)
Bolted F
a
ult
Curre
n
t (kA
)
Case 5
Case 6
Bus 2
11
11.
25
Bus 3
6.
6
6.
4
9.
55
PCC
0.
415
28.
012
51.
19
Thus, a com
p
romise has to be reached between reliab
ility
and
fault level of
syste
m
.
The design of
the
sy
st
em
as well
as t
h
e confi
gur
at
i
on i
n
whi
c
h i
t
i
s
ope
rat
e
d has a
m
a
jor im
p
act
on t
h
e arc f
l
ash l
e
vel
s
. The st
udy
shoul
d be carri
ed out
fo
r arc f
l
ash current
l
e
vel
s
and en
ergi
es keepi
ng al
l
the scenari
o
s of
sy
st
em
operat
i
on i
n
min
d
so
as to
ascertain
th
e b
e
st o
p
e
ratin
g
scen
ario
.
4.
P
RO
TECTIVE
D
EVICE
C
OOR
DINATION
Rela
ys p
r
ov
ided
at d
i
fferen
t
lev
e
ls, th
eir
sett
in
g
s
and
ch
aracteristics
d
a
ta fo
r th
e SLD g
i
v
e
n
is
d
e
ter
m
in
ed
b
a
sed
on
th
e l
o
ad
d
a
ta, fau
lt lev
e
ls, relay c
oor
di
n
a
t
i
on [6]
et
c. T
h
e co
ordi
nat
i
on cu
rves a
r
e as
gi
ven
bel
o
w.
As
of
n
o
w,
arc
fl
ash p
r
ot
ect
i
on i
s
n
o
t
t
a
ken i
n
t
o
co
n
s
i
d
erat
i
on and
cal
cul
a
ti
ons ar
e do
ne
onl
y
f
o
r
bol
t
e
d
fau
lt cu
rren
t
lev
e
ls.
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E Vol
.
3
,
No
. 1, A
p
ri
l
20
14
:
23
–
3
2
28
Fi
g. 1.
R
e
l
a
y
C
oor
di
n
a
t
i
on
of
4
1
5
V
sy
st
em
befo
re
arc fl
as
h cal
c
u
l
a
t
i
ons a
r
e t
a
ke
n i
n
t
o
c
o
n
s
i
d
er
at
i
o
n
Fi
g. 2.
R
e
l
a
y
C
oor
di
n
a
t
i
on
of
6
.
6
k
V
sy
st
em
befo
re
arc fl
as
h cal
c
u
l
a
t
i
ons a
r
e t
a
ke
n i
n
t
o
c
o
n
s
i
d
er
at
i
o
n
During
th
e
relay selectio
n
and co
ord
i
n
a
tion
wh
en
ar
c flash current is not taken i
n
to acc
ount, t
h
e two
m
o
st
im
port
a
nt
feat
ure
s
t
o
be
kept
i
n
m
i
nd a
r
e t
h
at
t
h
e sel
e
ct
i
v
e coo
r
di
nat
i
on s
h
o
u
l
d
be
st
ri
ct
l
y
fol
l
o
we
d i
.
e.
th
e break
er closest to
th
e
fau
l
t sh
ou
ld
op
erat
e first and
if it
fails to
op
er
ate, only then t
h
e upstream
bre
a
ker
shoul
d
operate
and in t
h
e eve
n
t of
startin
g
of h
i
gh
est rating
m
o
to
r wh
ile o
t
h
e
r con
n
ected
lo
ad
s are runn
ing
,
th
e r
e
lay should
h
a
v
e
a tim
e
d
e
lay g
r
eater
th
an
the star
tin
g
tim
e o
f
th
e
m
ach
in
e so
as to
avo
i
d
er
ron
e
ou
s
o
p
e
ration
o
f
t
h
e pro
t
ection
sy
ste
m
wh
en
th
ere is no
fau
lt.
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I
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2-8
7
9
2
Reme
di
at
i
o
n
of
Ol
d
S
u
b
st
at
i
o
ns f
o
r Arc
Fl
as
h
Haz
a
r
d
(
Z
aki
r
H
u
s
a
i
n
)
29
5.
A
RC
F
LASH
C
ALCULATI
O
N
Many
m
e
thods
for Arc
fault Hazard level calculati
on have
been given till now. Ralph Lee’s
m
e
thod is
one
of t
h
e fi
rst
m
e
t
hods but
i
t
gi
ves conse
r
vat
i
v
e resul
t
s
and
i
s
onl
y
referred
for
v
o
l
t
a
ge l
e
vel
s
bey
ond
15
k
V
for
which the t
e
sts by IEEE were not
carried out.
The IEEE 1584
m
e
thod
till now is the m
o
st accurate
m
e
thod
as i
t
has been f
o
u
nd
out
o
n
t
h
e basi
s of re
gre
ssi
on anal
y
s
i
s
of t
h
e ex
peri
m
e
nt
al
dat
a
obt
ained
by
carry
i
ng o
u
t
th
e test.
As per
IEEE
1
5
8
4
[
1
]
,
t
h
e em
pi
ri
cal
equat
i
ons fo
r arc
fl
ash
l
e
vel
s
are as gi
ven
bel
o
w:
a.
Arc Fault Current and Clearing tim
e
For PCC (<
1kV sys
t
em),
Arc Fau
lt Cu
rren
t,
I
a
= 10
(K + 0.66
2 l
og (I
bf
) + 0
.09
66V
+ 0
.
0005
26G
+ 0
.55
88V
lo
g (I
bf
) –
0.
003
04G
log
(I
bf
))
Where,
K = -
0
.
1
5
3
f
o
r
open
confi
g
urat
i
on a
n
d -
0
.0
97
fo
r b
o
x
co
nfi
g
u
r
at
i
o
n
V = sy
st
em
volt
a
ge i
n
kV,
G = co
nd
uct
o
r
gap i
n
m
m
I
bf
= Bo
lted
Fau
lt Cu
rren
t
I
a
= Arc fault Curre
nt
For
Voltages >1kV and
< 15kV,
I
a
= 10
(0.00402 + 0.98
3
lo
g
(I
bf
))
The fault clearing tim
e
for I
a
a
nd 85% of I
a
can be c
h
ecked
from
the relay operation curve.
Fro
m
th
is
calc
u
lated
arc fau
lt cu
rren
t
an
d
t
h
e fau
lt
clearing tim
e
, the incident
energy
at a distance of
610mm fro
m
the source of arc is ca lcula
t
ed as given
below:
b.
Norm
alized Incident Energy
and In
cident energy at
working distance
Norm
alized Energy,
En = 1
0
(
K
1 +
K2 +
1.0
8
1
l
o
g
Ia + 0.
00
11
G)
Where,
K1 = -
0
.
7
9
2
f
o
r o
p
en co
nfi
g
ur
at
i
on and
-0.
5
5
5
f
o
r bo
x confi
g
urat
i
on,
K2 =
0 f
o
r
un
g
r
ou
nde
d an
d hi
gh
resi
st
ance grou
ndi
n
g
an
d
-
0
.1
13
, gr
ou
nded
syste
m
E
n
is in
J/c
m
2
(5
J
/
cm
2
= 1.2 cal
/
c
m
2
)
Inci
dent
ener
g
y
,
E = 4.1
84C
f
E
n
(t/0
.2
) (6
10
x
/D
x
)
Where, C
f
= calculation factor
= 1, > 1kV
= 1.5,
<= 1k
V
x
= 1.4
73,
swi
t
c
hgear (<1
k
V
)
= 0.9
73,
swi
t
c
hgear (>5
–
15
k
V
)
D
= working distance in mm
En
= norm
a
li
zed in
cident energy
For
V> 1
5
k
V
,
R
a
l
ph Lee’s m
e
t
hod [
2
]
i
s
used f
o
r I
n
ci
dent
e
n
ergy
cal
cul
a
t
i
on
E = 2
.
14
2 X
1
0
6
V I
bf
(t/D
2
)
The arc flas
h c
u
rrent, its clearing tim
e,
incident energy rele
ased at wo
rking distance a
r
e provide
d
in the
Tabl
e I
II,
I
V
a
nd
V
fo
r di
ffe
r
e
nt
b
u
ses at
va
ri
o
u
s b
o
l
t
e
d
fa
ul
t
cur
r
ent
l
e
ve
l
s
fo
r co
nfi
g
u
r
at
i
ons c
onsi
d
er
ed
above.
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IJA
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.
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,
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. 1, A
p
ri
l
20
14
:
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–
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2
30
TABLE III.
INI
T
IA
L ARC
FL
ASH L
E
V
ELS
AS
PER
IEE
E
1584
(BUS
2)
Bus No.
Voltage
(k
V)
Case
Bolted Fault
Cu
rren
t
(k
A)
Arc F
a
ult
Cu
rren
t
(k
A)
100% and
85%
Ti
m
e
of
clearing
arc f
a
ult curr
ent
(sec)
I
n
cident E
n
er
gy
released at
wor
k
ing distance
(cal/c
m
2
)
Bus 2
11
1 16.
87
16.
23
0.
1
2.
184
13.
79
0.
1
1.
832
2 16.
87
16.
23
0.
1
2.
184
13.
79
0.
1
1.
832
3 22.
47
21.
51
0.
1
2.
962
18.
28
0.
1
2.
484
4 22.
47
21.
51
0.
1
2.
962
18.
28
0.
1
2.
484
5 11.
25
10.
9
0.
1
1.
42
9.
26
0.
1
1.
191
6 11.
25
10.
9
0.
1
1.
42
9.
26
0.
1
1.
191
TABLE IV.
INI
T
IA
L ARC
FL
ASH L
E
V
ELS
AS
PER
IEE
E
1584
(BUS
3)
Bus No.
Voltage
(k
V)
Case
Bolted Fault
Cu
rren
t
(k
A)
Arc F
a
ult
Cu
rren
t
(k
A)
100% and
85%
Ti
m
e
o
f
clearing arc
fault current
(sec)
I
n
cident E
n
er
gy
released at
working
distance (cal/c
m
2
)
Bus 3
6.
6
1 10.
93
10.
59
0.
2232
2.
7217
8
9 0.
2382
2.
4367
2 15.
2
14.
65
0.
1982
3.
4312
12.
45
0.
21
3.
0498
3 11.
42
11.
06
0.
2196
2.
8056
9.
4 0.
234
2.
5079
4 16.
5
15.
88
0.
1928
3.
6419
13.
5
0.
204
3.
2326
5 6.
4
6.
26
0.
2801
1.
9341
5.
32
0.
3038
1.
7597
6 9.
55
9.
28
0.
2353
2.
4859
7.
88
0.
252
2.
2334
TABLE V.
INI
T
IA
L ARC
FL
ASH L
E
V
ELS
AS
PER
IEE
E
1584
(PCC)
Bus No.
Voltage
(k
V)
Case
Bolted Fault
Cu
rren
t
(k
A)
Arc F
a
ult
Cu
rren
t
(k
A)
100% and
85%
Ti
m
e
o
f
clearing arc
fault current
(sec)
I
n
cident E
n
er
gy
released at
working
distance (cal/c
m
2
)
PCC 0.
415
1 28.
9
14.
16
0.
6608
19.
988
6
12.
04
0.
7137
18.
110
5
2 54.
32
23.
73
0.
5345
28.
247
1
20.
17
0.
5689
25.
221
1
3 29.
39
14.
36
0.
6567
20.
163
7
12.
2
0.
7088
18.
256
3
4 56.
02
24.
33
0.
5295
28.
755
8
20.
68
0.
5633
25.
662
6
5 28.
012
13.
8
0.
6686
19.
674
2
11.
73
0.
7226
17.
838
3
6 51.
19
22.
604
0.
5444
27.
3
19.
21
0.
58
24.
398
8
From
the above tables, it ca
n be clearly seen th
at
t
h
e m
o
st
fav
o
r
abl
e
s
c
hem
e
of ope
r
a
t
i
on u
nde
r
no
rm
al
condi
t
i
on i
s
C
a
se 1 wi
t
h
o
n
e t
r
ans
f
o
r
m
e
r onl
y
i
n
oper
a
t
i
o
n
.
When
wo
rk i
s
t
o
be do
ne o
n
e
n
er
gi
zed
equi
pm
ent
,
t
h
e best
m
ode o
f
ope
rat
i
on i
s
C
a
se 5 i
.
e. i
n
i
s
ol
at
ed co
nd
i
t
i
on wi
t
h
o
n
l
y
one t
r
a
n
sf
or
m
e
r i
n
ope
rat
i
o
n t
o
fe
ed eac
h
bu
s.
An
y ch
an
g
e
s in
th
e settin
g
of th
e
relay to
bring
dow
n the
clearing tim
e
so as
t
o
lower th
e in
ci
d
e
nt
en
erg
y
in
o
l
d
e
r p
l
an
ts
with
limited
ran
g
e
of settin
g
s
in
th
e ex
istin
g
electro
m
ech
an
ical relays resu
lts in
Relay
coo
r
di
nat
i
o
n d
i
st
urba
nce a
n
d
m
a
y
l
ead t
o
ope
rat
i
o
n o
f
t
h
e rel
a
y
eve
n
un
de
r t
h
r
o
ug
h
faul
t
co
n
d
i
t
i
ons a
n
d
isolation of
e
v
en norm
al
areas.
Und
e
r th
ese limita
tio
n
s
two
p
o
s
sib
l
e actions th
at can
b
e
tak
e
n are:
Evaluation Warning : The document was created with Spire.PDF for Python.
I
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2-8
7
9
2
Reme
di
at
i
o
n
of
Ol
d
S
u
b
st
at
i
o
ns f
o
r Arc
Fl
as
h
Haz
a
r
d
(
Z
aki
r
H
u
s
a
i
n
)
31
Zone
Selective Interloc
king
Zon
e
Selectiv
e In
terlo
c
k
i
ng
(ZSI) can
be i
n
corporated in s
u
ch
a case s
o
t
h
at if the
breaker nea
r
est to
th
e fau
lt senses it will g
i
v
e
l
o
ck
i
n
g
co
mm
a
n
d
to
t
h
e
up
strea
m
b
r
eak
er an
d
will clear t
h
e fau
lt with
ou
t an
y
in
ten
tio
nal ti
me d
e
lay irresp
ectiv
e of th
e settin
g
of th
e relay
.
Tempo
r
a
r
y Red
u
ced
Setting
Ano
t
h
e
r
feasible so
lu
tion
for
th
is is b
y
p
r
ovid
i
n
g
m
a
in
ten
a
n
ce
b
y
p
a
ss switch
wh
ich
will p
r
o
v
i
d
e
a
di
ffe
re
nt
set
of
rel
a
y
set
t
i
ngs du
ri
n
g
any
m
a
int
e
na
nce act
i
v
i
t
y
t
hus gi
vi
ng i
n
st
ant
a
neo
u
s c
l
earance o
f
arc
faul
t
or
by
p
r
o
v
i
d
i
n
g u
n
i
t
di
f
f
ere
n
t
i
a
l
prot
ect
i
on
on t
h
e b
u
s
,
t
h
e
faul
t
cu
rre
nt
l
e
vel
s
an
d t
h
us
t
h
e i
n
ci
de
nt
e
n
er
gy
can
be
red
u
ce
d
su
bst
a
nt
i
a
l
l
y
.
The l
e
vel
s
t
h
us
re
duce
d
a
r
e
gi
ven
i
n
Tabl
e
V
I
.
TABLE VI.
FINA
L ARC
FLA
S
H L
E
VE
LS
AS P
E
R I
EEE
158
4
B
Y
L
O
W
ERI
NG C
LEARI
NG
TI
ME
Bus
No.
Voltage
(k
V)
Bolted Fault
Cu
rren
t
(k
A)
Arc F
a
ult
Cu
rren
t
(k
A)
Ti
m
e
of
clearing
arc f
a
ult curr
ent
(sec)
I
n
cident E
n
er
gy
released at
working
distance (cal/c
m
2
)
Bus 2
11
16.
87
16.
228
3
0.
1
2.
184
Bus 3
6.
6
10.
93
10.
592
1
0.
1
1.
22
PCC 0.
415
28.
9
14.
161
5
0.
1
3.
025
The Fl
as
h Pr
ot
ect
i
on B
o
un
da
ry
i
s
defi
ne
d a
s
an ap
pr
oac
h
l
i
m
i
t
at a di
st
ance f
r
om
l
i
v
e
part
s t
h
at
are
uni
ns
ulated or
expose
d
within whic
h a
pers
on could r
eceive a second
de
gree burn
(I
E
E
E
1584[1]). It
can be
calculates as.
c.
Fl
ash P
r
ot
ect
i
on B
o
u
n
d
ary
D
B
= [4.184C
f
E
n
(t/0
.2
) (6
10
x
/E
B
)]
1/x
Or by
Lee’s m
e
t
hod,
D
B
= [2.142 X
10
6
V
I
bf
(t/E
B
)]
1/2
Where,
E
B
= 5 J/c
m
2
for b
a
re skin (seco
n
d
de
gree b
u
r
n
s,
curable)
=
33.
33
J/
cm
2
f
o
r PPE
of
8 cal
/
c
m
2
Thu
s
,
f
l
ash pro
t
ectio
n bou
ndar
y
i.e. saf
e
wo
rk
ing
d
i
stan
ce fo
r
b
a
re sk
in and
with
PPE of
8
cal/cm
2
[5]
bef
o
re
an
d after rem
e
diation
is
s
h
o
w
n
in
Table VI
I
a
n
d
VI
II.
TABLE VII.
FLASH
PROT
EC
TION
BOU
NDAR
Y BEFOR
E
RE
M
E
DIA
T
I
O
N
Bus No.
Voltage (kV)
Flash Pr
otection B
oundar
y
(m
)
I
E
EE
1584
1.
2 cal/cm
2
(bare s
k
in)
8 cal/c
m
2
(PPE
)
Bus 2
11
1.
68
0.
24
Bus 3
6.
6
2.
1
0.
3
PCC 0.
415
3.
4
1.
065
TABLE VIII.
FLASH
PROT
EC
TION
BOU
NDAR
Y AFT
E
R R
E
M
E
DIAT
ION
Bus No.
Voltage (kV)
Flash Pr
otection B
oundar
y
(m
)
I
E
EE
1584
1.
2 cal/cm
2
(bare s
k
in)
8 cal/c
m
2
(PPE
)
Bus 2
11
1.
68
0.
24
Bus 3
6.
6
0.
925
0.
132
PCC 0.
415
1.
071
0.
337
As ca
n
be see
n
fr
om
abo
v
e t
h
e ap
pr
oac
h
di
st
ances a
n
d i
n
ci
dent
e
n
e
r
gi
es
r
e
duce
d
c
o
nsi
d
e
r
abl
y
f
o
r
th
e 415
V PCC
syste
m
an
d
6
.
6k
V Bu
s.
W
i
t
h
PPEs
o
f
8 cal/cm
2
, th
e wo
rk
can
b
e
safely don
e
with
ou
t an
y
h
a
rm
to
th
e
operato
rs.
Evaluation Warning : The document was created with Spire.PDF for Python.
I
S
SN
:
2
252
-87
92
IJA
P
E Vol
.
3
,
No
. 1, A
p
ri
l
20
14
:
23
–
3
2
32
Arc Containm
ent De
vice
[6]
An
ot
he
r s
o
l
u
t
i
on t
h
at
can be
use
d
i
s
t
h
e arc
cont
ai
nm
ent
d
e
vi
ce [6]
w
h
i
c
h i
s
essentially an enclosure
cont
ai
ni
ng el
e
c
t
r
o
d
es.
W
i
t
h
t
h
e hel
p
o
f
t
r
i
g
erri
n
g
t
h
r
o
u
g
h
l
i
ght
sens
o
r
s a
nd C
T
i
n
p
u
t
t
h
e pl
asm
a
gun
can b
e
use
d
t
o
di
vert
t
h
e arc f
r
o
m
the swi
t
c
hgea
r
t
o
t
h
i
s
de
vi
ce
wi
t
h
i
m
pedanc
e l
o
we
r t
h
a
n
t
h
e arci
ng i
m
pedance
.
Thus arc curre
nt starts passi
ng through this cham
ber
and the interrupti
on
of a
r
c take
s place in 7-8m
s
as
com
p
ared t
o
al
m
o
st
100m
s t
a
ken
by
t
h
e
bre
a
ker
.
T
h
i
s
l
ead
s t
o
drast
i
c
red
u
ct
i
o
n
o
f
t
h
e a
r
c en
er
gy
an
d
safet
y
of worke
r
s.
The calculations
are s
h
own in
T
a
ble IX
with a
clearing tim
e
of
10m
s.
TABLE IX.
FLASH
PROT
EC
TION
BOU
NDAR
Y AFT
E
R R
E
M
E
DIAT
ION
WIT
H
THE
HE
LP O
F
A
RC CONTA
I
N
M
E
N
T
DEVIC
E
Bus No.
Voltage (kV)
Flash Pr
otection
Boundar
y
(m
)
I
E
EE
1584
1.
2 cal/cm
2
(bare
skin)
Bus 2
11
0.
158
Bus 3
6.
6
0.
087
PCC 0.
415
0.
263
B
u
t
p
r
i
o
r
t
o
u
s
i
ng t
h
e arc
c
ont
ai
nm
ent
de
vi
ce, i
t
s
effect on the B
I
L
of the system
or any
othe
r
harm
ful
ef
fect
s
d
u
ri
ng
n
o
r
m
a
l o
p
erat
i
o
n
o
f
t
h
e P
o
wer
sy
st
em
shoul
d
be
c
onsi
d
ere
d
.
C
a
r
e
sh
o
u
l
d
be
t
a
ken
s
o
t
h
at
t
h
i
s
uni
t
d
o
es n
o
t
o
p
erat
e un
der
no
rm
al
swi
t
c
hi
ng
op
eratio
n
s
. For th
is test sh
ou
ld b
e
carried
ou
t after
com
m
i
ssi
oni
ng
and
bef
o
re t
a
ki
n
g
i
n
t
o
l
i
n
e
.
Al
so, t
h
ere s
h
o
u
l
d
be p
r
ov
i
s
i
on o
f
chec
k
i
ng t
h
e c
o
n
d
i
t
i
on
o
f
electrodes
a
n
d replacem
ent
if require
d
duri
ng routine
m
a
intenanc
e
or a
f
ter failure
.
7.
CO
NCL
USI
O
N
Safet
y
of w
o
r
k
i
n
g per
s
o
n
n
el
i
s
param
ount
whi
l
e
carry
i
n
g
out
any
j
ob o
n
el
ect
ri
cal
equi
pm
ent
an
d
any
m
i
st
ake coul
d l
ead t
o
d
a
m
a
ge t
o
b
o
t
h
pers
o
n
n
e
l
w
o
r
k
i
n
g i
n
t
h
e
vi
ci
ni
t
y
and e
qui
pm
ent
.
To a
v
o
i
d su
c
h
occu
rre
nces
, A
s
m
u
ch as po
ss
i
b
l
e
, t
h
e m
a
i
n
tenance
w
o
r
k
o
n
any
el
ect
ri
ca
l
sy
st
em
shoul
d be ca
rri
e
d
ou
t
aft
e
r
de-e
ner
g
i
z
i
n
g t
h
e eq
ui
pm
ent
to be t
a
ke
n f
o
r
m
a
i
n
t
e
nance a
nd
pr
op
er w
o
r
k
pr
oce
d
ures a
nd c
h
eck
s sh
o
u
l
d
be
p
u
t
i
n
to
practice p
r
i
o
r to
startin
g th
e
jo
b.
Howev
e
r, i
f
it is im
p
o
ssib
l
e to
av
o
i
d
work
i
n
g
o
n
liv
e
p
a
n
e
ls
lik
e in
case of T
h
ermogra
phy etc., It has been found from
th
e above calculations that by
minor cha
nges i
n
the
Prot
ect
i
o
n l
ogi
c o
f
t
h
e
exi
s
t
i
n
g sy
st
em
t
h
e safet
y
of
t
h
e
w
o
r
k
i
n
g
pers
o
nnel
can
be e
n
s
u
re
d.
REFERE
NC
ES
[1]
IEEE
Guide
for
Perform
ing Arc
Flash Hazard
Ca
lcul
ations, IE
EE
Std 1584-2002.
[2]
R. H. Lee
.
“
T
he Other Ele
c
tri
c
a
l
Hazard: E
l
e
c
tri
c
Arc Burns
”
,
IEEE Power Syste
m
s Protection Committee Annua
l
Conf. and
Recor
d
, P
h
il
adelph
ia
,
P
A
, Oct. 5-9,198
1.
[3]
Doughty
,
R.L.,N
eal,T
.E.,and
Floy
d
,
H.L. “Predicting
incident energ
y
to better m
a
nage
the
electr
i
c ar
c hazard
o
n
600-V power di
stribution s
y
stems”,
IEEE Tran
sactions on Industry Applicat
io
ns
, Vol/Issue: 36(1). Pp. 257-269,
2000.
[4]
NFPA 70E,
Electrical Safety in
Workplace
, 200
9.
[5]
J.C. Das. “Prot
ection planni
ng
and s
y
s
t
em
de
s
i
gn to reduce arc flas
h incid
e
nt energ
y
in a m
u
ltivoltag
e
lev
e
l
distribution s
y
s
t
em to 8 cal/cm2 (H
RC2) or le
ss-Part 1. Methodolog
y
”
,
In co
nf. record, IEEE Pulp and Paper
Industry Conference
, San Anton
i
o, 2010
.
[6]
Roscoe, G
.
Pap
a
llo
T. and M
a
rcelo Vald
es P.E.
Arc
Flash Energy Mitigation
b
y
Fa
st Energy Captu
r
e
.
Evaluation Warning : The document was created with Spire.PDF for Python.