ABB REB670 Applications Manual page 328

Section 12
Control
322
tTrip , Long trip pulse
Usually the trip command and initiate auto-reclosing signal reset quickly as the fault is
cleared. A prolonged trip command may depend on a CB failing to clear the fault. A trip
signal present when the CB is reclosed will result in a new trip. Depending on the setting
Extended t1 = Off or On a trip/initiate pulse longer than the set time tTrip will either block
the reclosing or extend the auto-reclosing open time. A trip pulse longer than the set time
tTrip will inhibit the reclosing. At a setting somewhat longer than the auto-reclosing open
time, this facility will not influence the reclosing. A typical setting of tTrip could be close
to the auto-reclosing open time.
tInhibit , Inhibit resetting delay
A typical setting is tInhibit = 5.0 s to ensure reliable interruption and temporary blocking
of the function. Function will be blocked during this time after the tinhibit has been
activated.
tReset , Reset time
The Reset time sets the time for resetting the function to its original state, after which a line
fault and tripping will be treated as an independent new case with a new reclosing cycle.
One may consider a nominal CB duty cycle of for instance, O-0.3sec CO- 3 min. – CO.
However the 3 minute (180 s) recovery time is usually not critical as fault levels are mostly
lower than rated value and the risk of a new fault within a short time is negligible. A typical
time may be tReset = 60 or 180 s dependent of the fault level and breaker duty cycle.
StartByCBOpen
The normal setting is Disabled. It is used when the function is started by protection trip
signals. If set On the start of the autorecloser is controlled by an CB auxiliary contact.
FollowCB
The usual setting is Follow CB = Disabled. The setting Enabled can be used for delayed
reclosing with long delay, to cover the case when a CB is being manually closed during
the "auto-reclosing open time" before the auto-reclosing function has issued its CB
closing command.
tCBClosedMin
A typical setting is 5.0 s. If the CB has not been closed for at least this minimum time, a
reclosing start will not be accepted.
CBAuxContType , CB auxiliary contact type
It shall be set to correspond to the CB auxiliary contact used. A NormOpen contact is
recommended in order to generate a positive signal when the CB is in the closed position.
1MRK 505 337-UUS -
Application manual