GE Industrial Solutions WavePro - Manuel (Page 13)

Power+™ Trip Units
Chapter 2. Trip Unit Setup
7
Figure 8. Time-current curve illustrating instantaneous pickup.
2–7 Ground-Fault Pickup
Ground-fault pickup is available only with the installation
of a rating plug equipped with ground fault. This function
sets the pickup current for ground-fault protection. The
available settings are listed in Table 10 as multiples of X,
the current sensor rating. The maximum setting may be
less than .6, depending on the breaker frame size. Figure 9
illustrates the time-current curve for ground-fault pickup.
Breaker Frame Settings as Multiple of X
800–2000 A .20, .25, .30, .35, .40, .45, .50, .60
3200 A .20, .22, .24, .26, .28, .30, .34, .37
4000–5000 A 20, .22, .24, .26, .28, .30
Table 10. Settings available for ground-fault pickup according to
breaker frame size.
Figure 9. Time-current curve illustrating ground-fault pickup.
2–8 Ground-Fault Delay
Ground-fault delay is available only with the installation of
a rating plug equipped with ground fault. This function
sets the delay before the breaker trips when the ground-
fault pickup current is detected. The switch settings
MIN ,
INT , and MAX correspond to nominal time delays of .10,
.21, and .35 second, respectively. The delay with I 2 T OUT is
for the lower limit of each band. The delay with I 2 T IN is at
200% of the pickup setting at the lower limit of the band.
The I 2 T OUT function, illustrated in Figure 10, establishes a
constant time delay. I 2 T IN biases the delay with a constant
slope, as shown in Figure 11.
Figure 10. Time-current curve illustrating ground-fault delay with I 2 T
OUT.
Figure 11. Time-current curve illustrating ground-fault delay with I 2 T
IN.