I.B. 17555C
Effective November 1999
Page 9
Phase Inverse Time Overcurrent Time Multiplier:
The available time settings, shown in Table 2.2, depend
on the curve shape selected. For the thermal curves, the
settings represent relay operating times at a current value
equal to 3 times (I
n
). For ANSI and IEC curves, the set-
tings represent the relay’s time multiplier for the current
value equal to I/I
pu
.
Phase Short Delay Pickup: The available pickup set-
tings, shown in Table 2.2, range from 1 to 11 times (I
n
) or
NONE. If NONE is selected, the short delay protective
function is disabled.
Phase Short Delay Time: The available time settings,
shown in Table 2.2, range from 0.05 to 1.5 seconds at
currents equal to or above the short delay pickup setting
selected. If NONE was selected for the Phase Short
Delay Pickup Setting, the relay will bypass requesting the
time setting.
Phase Instantaneous: The available pickup settings,
shown in Table 2.2, range from 1 to 25 times (I
n
) or
NONE. If NONE is selected, the instantaneous protective
function is disabled and a choice of whether to turn the
discriminator option on (DON) or off (DOFF) is offered.
The discriminator is a true making current release. When
the circuit breaker closes, the discriminator function, if
selected to be on, is functional in an instantaneous trip
mode for 10 cycles after the breaker closes. The breaker
will trip instantaneously via the discriminator, if the fault
current is above 11 times (I
n
). After the 10 cycle period
has passed, the discriminator will no longer be functional.
It becomes functional again only when the breaker opens
and then is reclosed.
Ground Fault: After the phase instantaneous setting is
established, the ground curve shape, the ground inverse
time overcurrent pickup, ground inverse time overcurrent
time, ground short delay pickup, ground short delay time
and ground instantaneous settings are selected. The
available settings are shown in Table 2.3. Note that the
ground curve settings are independent of the phase
curve and are programmed separately.
Programming the ground settings is done in the same
manner as the phase settings, except there is no discrim-
inator option for ground instantaneous, and there is a
NONE selection for the inverse time overcurrent pickup
setting.
Note: The DT3000 displays pickup settings in the
“Settings” window to three significant digits only. If
there is a 4th digit in the setting, it will not be
displayed in the “Settings” window.
TABLE 2.4 MISCELLANEOUS SETTINGS
TYPE SETTING AVAILABLE SETTINGS
HIGHLOAD TIME
(pickup fixed @ 0.85 X Phase
Time Overcurrent Setting)
0 Sec, 5 Sec, 10 Sec, 30 Sec, 1 min, 2 min, 5 min
FREQUENCY 50 Hz, 60 Hz
PHASE CT RATIO 5,10, 25, 50, 75,100,150, 200, 250, 300, 400, 500, 600, 630,
800,1000,1200,1250,1500,1600, 2000, 2400, 2500, 3000,
3200, 4000, 5000
GROUND CT RATIO 5,10, 25, 50, 75,100,150, 200, 250, 300, 400, 500, 600, 630,
800,1000,1200,1250,1500,1600, 2000, 2400, 2500, 3000,
3200, 4000, 5000
TEST
Phase
Phase Trip
Ground
Ground Trip
P1, P2, P3, P4, P5, P6, P7, P8, P9, P10, P12, P14, P16
P18, P20, P22, P25
P3T, P10T, P25T
G.1, G.2, G.3, G.4, G.5, G.6, G.7, G.8, G.9, Gi, G2, G3, G4
G5, G6, G8, G10
G1T, G3T, G10T
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