GE AKR User Manual

Ground
Fault Protection
A
ground
fault
is
uninten
-
tional
current
flowing
from
a
circuit
through
a
conducting
path
to
ground
.
It
is
usually
l
*
t
Function
An
l
2
t
function
is available
with
MicroVersaTrip
.
®
This
provides
a
ramp
function
(
l
2
t
=
constant
)
in
the
short
-
time
and
ground
fault
char
-
of
a
low
magnitude
{
less
acteristic
(
See
Fig
.
16.1
)
that
allows
maximum
coor
-
value
)
and
not
sensed
by
the
dination
with
downstream
thermal
-
magnetic
protective
modern electronic
trip
devices
that
follow
a curve
instead
of
a
square
path
.
The
l
2
t
function
also
allows
tighter
motor
protection
by
accommodating
the
tran
-
sient
inrush
while the
short
-
time
pickup
remains
just
slightly higher
than
the
steady
state
starting
current
.
In
other words
,
the
path
fol
-
plex
collection
of
external
lows
the
hypotenuse
in
-
stead
of
the
right
angle
.
When the
square
short
-
time
ground
fault
and
signal
a
path
might
intersect
with
a
downstream
fuse
or
breaker
,
the
l
2
t
function
per
-
delay
bands
with
l
2
t
in
and
mits
the
short
-
time
delay
path
to
veer
in
front of
the
time
current
curve
for
the
8
8
2
S
4
$ $
7
|
*
10
H
.
1
-
t
.
7
M I
I
»
H
51
B
)
0
HN
:
ltd
7
Ml
toe
/
700
MO
r
/
MO
GROUND
FAULT
/
PICKUP
IDO
y
'
A
than
the
long
-
time
pickup
200
protective
device
.
Using
/
100
«
0
'
•
0
devices
,
protection
against
ground
faults
can
be
built
into
a
distribution
protection
system
with
ground
fault
pickup
and
delay
functions
added
to
the
circuit
break
-
er
’
s
fault
interrupting
capa
-
bility
.
Before
electronic
trips
came
on
the
scene
,
a
com
-
70
«
0
so
40
'
'
lauiLr
30
'
-
/
20
/
X
V
GROUND
FAULT
DELAY
!
*
T IN
l
*
T
OUT
10
7
I
7
MAX MAX
/
'
/
6
1
/
7
in
5
relays
and
current
sensors
were
needed
to
sense a
a
V
z
V
,
o
«
/
/
IA
/
z
/
u
breaker
to
trip
.
Eight
ground
fault
pickup
levels and three
m
%
^
m
in
in
IN
our
i
KB
9
out to
allow
full
selectivity
,
insuring
that
only
the
breaker
closest
to
the
downstream
device
.
Without
ground
fault
will
trip
.
Addi
-
this
function
,
coordination
and
selectivity
would be
dif
-
locking
for
the
ground
fault
ficult
to
attain
.
SIS
OUT
SIS
1
Y
A
SS
SIS
!
KZ
res
g
5
f
5
*
r
<
tVPCB
MC
a
.
icce
Mai
4
55
cx
*
L
tion
of
zone
selective inter
-
>
C
LVPC
8
MC
S
ICCB
i
x
V
,
\
N
A
r
XX
4
,
J
ivpce
MC
.
&
ICCB
suss
Hi
BSSSSSSSS
*
function further
enhances
1
v
\
\
\
this
protection
by
permitting
"
timed
”
tripping
and
closer
back
-
up
protection
.
x
.
\
i
0
»
Dt
01
M
.
05
0
»
.
0
)
.
02
.
01
I
4
S
•
7
•
I
10
20
30
40 10
ID
701
DM
s
i
7
i
a
Fig
17.1
Time
Current
Curve Definition
Ground
Fault
17
Courtesy of store.ips.us

GE AKR Specifications

General

Standards	UL489, IEC 60947-2
Voltage Rating	600V
Mounting	Fixed, Drawout
Poles	3
Trip Unit	Electronic
Operating Temperature	+70°C