ABB 615 series Technical Manual page 219

1MAC059074-MB A
615 series ANSI
Technical Manual
GUID-640654EC-1E77-4ED5-BE41-9EC399B686BA-ANSI V1 EN
Figure 106: Pickup value behavior with ENA_MULT input activated
Phase selection logic
If the fault criteria are fulfilled in the level detector, the phase selection logic detects the
phase or phases in which the measured current exceeds the setting. If the phase
information matches the Num of pickup phases setting, the phase selection logic activates
the timer module.
Timer
Once activated, the timer activates the PICKUP output. Depending on the value of the
Operating curve type setting, the time characteristics are according to DT or IDMT. When
the operation timer has reached the value of Trip delay time in the DT mode or the
maximum value defined by the inverse time curve, the TRIP output is activated.
When the user-programmable IDMT curve is selected, the operation time characteristics
are defined by the parameters Curve parameter A, Curve parameter B, Curve parameter
C, Curve parameter D and Curve parameter E.
If a drop-off situation happens, that is, a fault suddenly disappears before the trip delay is
exceeded, the timer reset state is activated. The functionality of the timer in the reset state
depends on the combination of the Operating curve type, Type of reset curve and Reset
delay time settings. When the DT characteristic is selected, the reset timer runs until the set
Section 4
Protection functions
213