Time Delay - ABB REG650 Technical Manual

1MRK 502 043-UUS B
10.3.6.2
Technical Manual
negative value, and a trip signal has been issued, then a 100 ms pulse is issued on the
RESTORE output, when the frequency recovers to a value higher than the setting
RestoreFreq. A positive setting of PUFreqGrad, sets SAPFRC (81) to PICKUP and
TRIP for frequency increases.
To avoid oscillations of the output PICKUP signal, a hysteresis has been included.

Time delay

SAPFRC (81) has a settable definite time delay, tTrip.
Trip signal issuing requires that SAPFRC (81) condition continues for at least the user
set time delay, tTrip. If the PICKUP condition, ceases during the delay time, and is not
fulfilled again within a defined reset time, the PICKUP output is reset after the reset
time has elapsed.
After an issue of the TRIP output signal, the RESTORE output of SAPFRC (81) is set,
after a time delay tRestore, when the measured frequency has returned to the level
corresponding to RestoreFreq. If tRestore is set to 0.000 s the restore functionality is
disabled, and no output will be given. The restore functionality is only active for
lowering frequency conditions and the restore sequence is disabled if a new negative
frequency gradient is detected during the restore period.
Section 10
Frequency protection
301