ABB RER620

Section 10 1MAC309294-MB F
General function block features
460 RER620
Technical Manual
Figure 239: Drop-off period is longer than the set Reset delay time
When the drop-off period is longer than the set Reset delay time, as described in Figure
221, the input signal for the definite timer (here: timer input) is active, provided that the
current is above the set Pickup value. The input signal is inactive when the current is below
the set Pickup value and the set hysteresis region. The timer input rises when a fault current
is detected. The definite timer activates the PICKUP output and the trip 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 trip timer is reset. Since this
happens before another pickup occurs, the TRIP output is not activated.