ABB Relion 611 Series, Technical Manual

Page: 447 / 536

When the drop-off period is longer than the set Reset delay time , as described in Figure
215 , 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
START
output and the
operate timer starts elapsing. The reset (drop-off) timer starts when the timer input
falls, that is, the fault disappears. When the reset (drop-off) timer elapses, the operate
timer is reset. Since this happens before another start occurs, the
OPERATE
output is
not activated.
A070420 V1 EN
Figure 216: 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 216 , 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
START
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
OPERATE
output, since the
operate timer already has elapsed.
1MRS757454 D
Section 9
General function block features
611 series 441
Technical Manual