Eaton Cutler-Hammer Digitrip RMS 510 - Section 10 Digitrip RMS Retrofit

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33-855-4
Page 51
SECTION
1O DIGITRIP
RMS
RETROFIT
SWITCHGEAR
ASSEMBLY
APPLICATIONS
1O.1 Zone
lnterlocking
Zone Selective
lnterlocking
(ZSl)
capabilities
are
available
with Digitrip
RMS 510, 610,
810, & 910
Trip Units.
ZSI
provides positive
system
coordina-
tion by
allowing
the Breaker closest
to the
fault to
trip without any
preset
time delay.
This
is
achieved
by setting up
the distribution
system as
shown
in
the
adjacent
diagram.
The hard
wired connection
between
Trip Units sends
a restraining
signal
upstream,
allowing
the Breaker
closest to the
fault
to trip
instantaneously.
ZSI's
superior system
coordination
ensures
that
the Breaker closest
to the
fault will
trip without
preset
time delays
while reducing
stress on
the
distribution
system.
10.1.1
Zone Selective
lnterlocking
Fig.
10-1 Zone Selective
Interlocking
Fault
1
-
There are
no interlocking
signals.
The main
Breaker Trip Unit
will initiate
the trip
instantaneously.
Fault 2
-
The feeder
Breaker
Trip Unit will
initiate
the
trip instantaneously
to clear the
fault; and
Zone
2
will send
an interlocking
signal
to the Zone
1 Trip
Unit. The
Zone 1 Trip
Unit will begin
to time
out
and,
in ihe event
that the
feeder Breaker
in Zone
2
would not clear the
fault.
the main Breaker
in Zone
'1
will clear
the fault
in
0.5
seconds.
Fault 3
-
The branch
Breaker
Trip Unit
will initiate
the trip instantaneously
to clear
the fault; Zone 3
will send
an interlocking
signal
to the Zone
2 Trip
Unit; and
Zone 2
will send an
interlocking
signal
to
Zone 1
.
Zone
1 and Zone
2 Trip Units
will begin
to time out
and,
in the event
that
the branch breaker
in Zone
3
would
not clear
the fault,
the feeder breaker
in
Zone 2
will clear the
fault in 0.3 seconds.
Similarly,
in the
event that
the feeder
breaker in Zone
2
would not clear
the fault,
the main breaker
in Zone
1 will clear
the
fault in 0.5 seconds.
NOTE: Digitrip
RMS
Zone lnterlocking
will trip
the
Breaker
instantaneously
on Short
Time
(S)
or Ground
Fault
(G)
Delay
Trip Functions
unless it is defeated
as described
in the
following
text.
For RMS
510 Basic
Retrofit
Kits, Zone lnterlock
functions
are
not wired out
from the
Trip Unit.
The External
Harness
provided
consists
of a small
jumper
plug
that shods out
the Zone
lnterlock
signals
at
the Trip Unit.
For RMS
510 Zone,
610, 810, & 910
Retrofit
Kits,
Zone lnterlock
functions
are available
at the Cell
Harness
assembly
as shown
in Figure
12-12.The
Breaker External
Harness
plugs
into the Cell
Harness
Assembly,
which
includes
provisions
for
external
wiring connections
as shown
in Figure
12-12. Shorting
jumpers
are
provided
at
the Termi-
nal
Block Assembly
to defeat
the Zone
lnterlock
functions.
These
jumpers
can be
removed
and
selective
Zone lnterlocking
schemes
applied.
Typical
connection
schemes
for multiple
Circuit
Breakers are
shown
in Figures 10-2
and 10-3.
i
5OOA P1CKUP
i
0.3 sEcoNDs
rME DELAY
i.-2qNs
sg1s611yg
i
INTERLOCK
WIRING
BREAKER
NUMBER 1
GROUND
FAULT
SETTING:
l2OOA
PICKUP
0.5
SECONDS
TII\IE DELAY
BREAKER
NUMBER 2
GROUND
FAULT SETTING:
i
BREAKER
NUMBEB 3
--J
GROUND
FAULT SETTING:
3OOA
PICKUP
NO TIME DELAY
Etfective 9/01
FlT.il