Cutler-Hammer Digitrip OPTIM 1050, Инструкция по эксплуатации и обслуживанию

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I.B. 29C891B
Page 29
Effective 11/98
• DSII/DSLII
- 1.5 to 10.0 times (I
r
) in 0.1 increments
Figure 3-9 graphically illustrates how the short delay
pickup portion of the overall curve can be moved hori-
zontally and independently by means of the programma-
ble settings.
Short Delay Time Setting (I
2
t or Flat Slopes)
The short delay time setting is programmable from 0.1
to 0.5 seconds in 0.01 increments for all OPTIM Trip
Units. The short delay time setting is programmable to
an
I
2
t or a Flat slope . The 0.1 to 0.5 second setting is
the nominal trip time at 8.0 times I
r
for I
2
t slope.
Notice: (1) When an I
4
t slope is programmed for the
long delay time setting, the short delay
time setting must be set to a FLAT slope.
(2) When an I
2
t slope is programmed for the
long delay time setting, the short delay
time setting may be set to FLAT or I
2
t.
The short delay time setting establishes the amount of
time a short-circuit will be carried before the circuit
breaker trips. Figures
3-10 and 3-11 graphically illus-
trate how the short delay time portion of the overall
TIME
CURRENT
Note: Short Delay Time
Setting represented
by dotted lines
Figure 3-11 Typical Short Delay Time Adjustment, (I
2
t)
Response
TIME
CURRENT
Note: Short Delay Time
Setting represented
by dotted lines
Figure 3-10 Typical Short Delay Time Adjustment, Flat
Response
curve can be moved vertically and independently by
means of programmable settings.
Zone Selective Interlocking (OPTIM Models 750 and
1050)
Zone selective interlocking is provided for the short
delay and the ground fault delay tripping functions for
improved system protection. The Digitrip OPTIM Trip
Unit zone selective interlocking feature is compatible
with Digitrip Trip Units, Model 510 and higher.
The zone selective interlocking feature is a means of
communications over a pair of wires between two or
more compatible trip units. Zone selective interlocking
makes it possible for programmed trip unit settings to be
altered automatically to respond to different fault condi-
tions and locations, thereby localizing the effects of an
interruption and providing positive coordination between
circuit breakers.
Figure 3-12 illustrates a typical ground fault protection
scheme using zone selective interlocking. For faults out-
side the zone of protection, the trip unit on the circuit
breaker nearest the fault sends an interlocking signal to
the trip unit of the up-stream circuit breakers. This inter-
locking signal restrains immediate tripping of the
upstream circuit breakers until their programmed coordi-