Ground-Fault Delay; Voltage-Unbalance Relay Pickup; I2T Out - GE MicroVersaTrip Plus Series User Manual

(l)
E
i-=
Current
Figure 22. Time-current curve for ground-fault pickup.

Ground-Fault Delay

This function sets the delay before the breaker trips
when the ground-fault pickup current has been
detected. The Trip Unit display is shown in Figure
23. The choices are listed in Table 15. The delay for
I 2 T OUT
is at the lower limit of each band. The delay
I 2 T IN
for is at 200% of the pickup setting at the
lower limit of the band.
I 2 T OUT
The function establishes a constant time
delay, as shown in Figure 24.
with a constant slope, as shown in Figure 25.
With the X or GD options (switchable ground fault) ,
an selection appears as an additional time-delay
O F F
set point. Selecting
O F F
tion.
'
'
GF
Figure 23. Trip Unit display for ground-fault delay, showing
Ground-Fault
Pickup Settings
I 2 T IN
biases the delay
disables ground-fault protec­
SETUP
DELAY
out.
Band
OFF
1
2
3
Table 15. Lower-limit delays for ground-fault delay bands.
(l)
E
i-=
Figure 24. Time-current curve for ground-fault delay with
(l)
E
i-=
Figure 25. Time-current curve for ground-fault delay with
t2r

Voltage-Unbalance Relay Pickup

This function compares the highest or lowest phase
voltage with the average of all three phases and
initiates a trip if the difference exceeds the set point.
The true rms voltage is computed for each phase.
The range of set points is from 1 0 to 50% of the
unbalance, with an increment of 1 % . The Trip Unit
display is shown in Figure 26.
19
2.
Time Delay, sec
Disabled
0.10
0.21
0.35
Delay Set Points
Current
OUT.
Delay Set Points
12T
with I N
Current
t2r
frtN.