Retrip; Backup Trip; Remote Trip; Unconditional Trip - ABB REG316 4 Series Operating Instructions Manual

ABB Switzerland Ltd
4.2.7.4.

'Retrip'

The unit protection issues a trip command and simultaneously
starts individual phases or all three phases of the breaker fail
function.
A second attempt is made to trip the corresponding phase or
phases after the first time step (t1), providing the current detec-
tors have not reset.
The 'Retrip' logic can be disabled if not required.
Separate timers for each phase ensure correct operation during
evolving faults.
4.2.7.5.

'Backup Trip'

A second time step (t2) follows the first time step (t1) and initi-
ates backup tripping which is always of all three phases. If the
first time step is disabled, the second time step is started imme-
diately, providing the current detectors have activated by the
starting signal from the protection.
The backup trip logic trips all surrounding breakers feeding the
fault.
4.2.7.6.

'Remote Trip'

The 'Remote Trip' logic trips the breaker at the remote end of the
line.
Remote tripping can take place concurrently with the 'Retrip' or
'Backup' functions or not at all as desired.
In contrast to the other tripping commands which remain activate
for a given period after the initiating signal has reset, the remote
tripping signal is an impulse with a width which is adjustable irre-
spective of when the starting signal from the protection resets.
4.2.7.7.

'Unconditional Trip'

This feature was introduced to respond to low-level faults with
currents too low for the current detectors to pick up or do not ini-
tially cause any fault current at all such as mechanical protection
devices like Buchholz, etc.
The start input bypasses the current detectors and activates the
time steps if the breaker is in the closed position. In all other re-
spects, this logic is similar to the 'Retrip' and 'Backup' logics.
4-44
REG 316*4 1MRB520049-Uen / Rev. B