2.4 Time Overcurrent Protection for Phase and Residual Currents
155
7UT613/63x Manual
C53000-G1176-C160-2
lected tripping characteristic. After expiration of this time period, a trip command is
output as long as no inrush current is detected or inrush restraint is disabled. If inrush
restraint is enabled and inrush current is detected, there will be no tripping. Neverthe-
less, an annunciation is generated indicating that the time expired.
For the zero sequence current 3I0p the characteristic can be selected independently
of the characteristic used for the phase currents.
The pickup values of the stages Ip (phases) and 3I0p (zero sequence current) and
the time multipliers valid for each of these states can be set individually.
Figures 2-69 and 2-70 show the logic diagrams of the inverse overcurrent time protec-
tion for phase currents I
p
and for the zero sequence currents 3I0p.
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