Ground-Fault Delay; Voltage-Unbalance Relay Pickup; Time-Current Curve For Ground-Fault Pickup; Trip Unit Display For Ground-Fault Delay, Showing - GE MicroVersaTrip Plus User Manual

MicroVersaTrip Plus™ and MicroVersaTrip PM™ Trip Units
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
OFF
set point. Selecting
OFF
tion.
Figure 23. Trip Unit display for ground-fault delay, showing
I 2 T IN
biases the delay
disables ground-fault protec-
out.
B B B B a a a a n n n n d d d d
OFF
Table 15. Lower-limit delays for ground-fault delay bands.
Figure 24. Time-current curve for ground-fault delay with
Figure 25. Time-current curve for ground-fault delay with
I 2 T

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 10 to 50% of the
unbalance, with an increment of 1%. The Trip Unit
display is shown in Figure 26.
19
Chapter 2. Setup Mode
T T T T i i i i m m m m e e e e D D D D e e e e l l l l a a a a y y y y , , , , s s s s e e e e c c c c
Disabled
1 0.10
2 0.21
3 0.35
.
OUT
I 2 T
I 2 T IN
.