ABB RELION REX640 Technical Manual page 861

1MRS759142 F
When the operation timer has reached the value set by
mode or the maximum value defined by the IDMT, the OPERATE output is activated.
When the user-programmable IDMT curve is selected, the operate time
characteristics are defined by the parameters
B , Curve parameter C , Curve parameter D and Curve parameter E .
If a drop-off situation occurs, that is, a fault suddenly disappears before the operate
delay is exceeded, the reset state is activated. The behavior in the drop-off situation
depends on the selected operate time characteristics. If the DT characteristics are
selected, the reset timer runs until the set
the drop-off situation exceeds the set
START output is deactivated.
When the IDMT operate time curve is selected, the functionality of the Timer in the
drop-off state depends on the combination of the
reset and Reset delay time settings.
Table 792: Reset time functionality when IDMT operation time curve selected
Reset functionality
Instantaneous
reset
Frozen timer
Linear decrease
REX640
Technical Manual
Reset delay time , the Timer is reset and the
Setting Type of
reset curve
Operation timer "Immediate"
is "Reset instan-
taneously" when
drop-off occurs
Operation timer "Def time reset"
is frozen during
drop-off
Operation timer "Def time reset"
value linearly de-
creases during
the drop-off sit-
uation
Protection functions
Operate delay time in the DT
Curve parameter A , Curve parameter
Reset delay time value is exceeded. If
Type of reset curve , Type of time
Setting Type of
time reset
Setting has no
effect
"Freeze Op tim-
er"
"Decrease Op
timer"
Setting Reset
delay time
Setting has no
effect
Operate timer is
reset after the
Reset delay
set
time has elapsed
Operate timer is
reset after the
Reset delay
set
time has elapsed
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