ABB RELION REB500 Technical Manual page 149

1MRK 505 406-UEN B
Discrimination times (t 1P discrim. and t 3P discrim.)
The discrimination time determines the procedure in the event of a different kind of fault
occurring during the dead time (evolving fault), that is, one of the other two phases also picks
up or the tripping signal resets and picks up again. The discrimination time is started together
with the dead time. Should a tripping signal recur due to an evolving fault between the expiry
of the discrimination time and before the end of the dead time, the reclaim timer is started
and a definitive trip (Def. Trip) initiated. The dead time is also discontinued and the signal AR
in prog. reset.
If the first fault was initially an earth fault and evolves during the time
the end of the discrimination time
phase reclosure takes place.
The discrimination time
circuit-breaker has its own autoreclosure function.
A typical setting for the parameters
reclosure is 50% of the shortest dead time.
The minimum permissible setting for the discrimination time is:
100 ms + CB time
The distance protection parameter
subsequent fault (evolving or unsuccessful reclosure) results in a three-phase trip, that is,
every second trip by the distance protection function trips all three phases. The autoreclosure
function also signals the switchover to three-phase tripping by exciting the signal Trip 3-Pol at
the end of the fault discrimination time
It is advisable to set the time t1EvolFaults longer than the autoreclosure dead time t Dead1 1P.
t Timeout
The parameter
signal must be issued, otherwise a Def.Trip is generated and no further reclosure attempt is
made. Before a close command is issued at the end of every dead time, the logic [(synchroChck
AND CO ready) OR Dead Line OR ExtSCBypas)] is checked and the command only enabled
providing all the criteria are correct within the setting of
Blocking time (t AR Block)
The autoreclosure function can be enabled or disabled by the following binary input signals:
• ExtBlkAR also blocks during the reclosure cycle
• Manual close also blocks during the reclosure cycle
• Inhibit Inp also blocks during the reclosure cycle
• CB Ready blocks excepting during the reclosure cycle
• CB2 Ready blocks excepting during the reclosure cycle 1)
• CO Ready blocks at the end of the reclosure cycle after expiry of the time
• CO Ready 2 blocks at the end of the reclosure cycle after expiry of the time
• Mast.noSucc blocks the follower CB after an unsuccessful reclosure attempt by the
master
• CondBlkAR blocks excepting during the reclosure cycle
1) 2 denotes the inputs for CB2 in a duplex scheme.
Bay protection functions REB500
Technical manual
t Discrim 1P , the dead time t Dead1 3P is started and three-
t Discrim 3P is also needed for 2 or 1½ breaker schemes, where each
t Discrim 1P or t Discrim 3P for single- and three-phase
The time t1EvolFaults during which a subsequent fault has to be detected
(evolving or unsuccessful reclosure) is a distance function setting.
t1EvolFaults enables the time to be set during which a
t Timeout determines the period after the dead time within which the close
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t Discrim. 1P .
t Timeout .
Section 5
Bay protection functions
t Dead1 1P , but before
t time-out
t time-out 1)
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