ABB Relion 611 Series, Technical Manual

Page: 260 / 536

When the operation timer has reached the value set by Operate delay time in the DT
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
Curve parameter A , Curve parameter 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
Reset delay time value is exceeded. If the
drop-off situation exceeds the set Reset delay time , the Timer is reset and the
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
Type of reset curve , Type of time reset
and Reset delay time settings.
Table 265: Reset time functionality when IDMT operation time curve selected
Reset functionality Setting Type of
reset curve
Setting Type of time
reset
Setting Reset delay
time
Instantaneous
reset
Operation timer is
“Reset
instantaneously”
when drop-off
occurs
“Immediate” Setting has no
effect
Setting has no
effect
Frozen timer Operation timer is
frozen during
drop-off
“Def time reset” “Freeze Op timer” Operate timer is
reset after the set
Reset delay time
has elapsed
Linear decrease Operation timer
value linearly
decreases during
the drop-off
situation
“Def time reset” “Decrease Op
timer”
Operate timer is
reset after the set
Reset delay time
has elapsed
Section 4
1MRS757454 D
Protection functions
254 611 series
Technical Manual