ABB RELION 630 Series Technical Manual page 328

Section 9
General function block features
322
Timer input
OC_STR
OC_OPR
Reset timer
Operate timer
GUID-172943A9-F4AD-4B8A-A47F-E8BC032EE30D V1 EN
Figure 168: Drop-off period is shorter than the set Reset delay time
When the drop-off period is shorter than the set Reset delay time, as described in
Figure 168, the input signal for the definite timer (here: timer input) is active, provided
that the current is above the set Start value. The input signal is inactive when the
current is below the set Start value and the set hysteresis region. The timer input rises
when a fault current is detected. The definite timer activates the OC_STR output and
the operate timer starts elapsing. The Reset (drop-off) timer starts when the timer input
falls, that is, the fault disappears. Another fault situation occurs before the reset (drop-
off) timer has elapsed. This causes the activation of the OC_OPR output, since the
operate timer already has elapsed.
If the RESET_OC (Overcurrent reset) input is activated when the operate timer is
running as described in Figure
resets the OC_STR and OC_OPR outputs.
Reset delay time
Operate delay time
169, the operate timer and the reset timer reset. It also
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