Protection General
169
7SS52 V4 Manual
C53000-G1176-C182-1
5.9.7 Busbar Tripping via an External Signal
Apart from the tripping of bus zones by the busbar protection itself, there is the option
of tripping individual bus zones via an external signal. With enclosed switchgear, for
example, the output signal of a so-called arc barrier can be coupled in the central unit
via a binary input and be used to trip the faulty zone. For safety reasons the coupling
is carried out via one binary input per bus zone with an additional common release via
another binary input.
• The alarm ">TRIP-Release" (FNo. 10487/CU) is generated for the release and
">Trip $xx" (FNo. 177.1360.xx/CU) is generated for each triggering.
This is followed by the confirmation alarm "Trip BI $nn" (FNo. 177.1363.xx/
CU) and the group alarm "Device trip M" (FNo. 10445/CU). In this, xx or $nn
indicates the bus zone.
The monitoring of the inputs is done the same way as with the breaker failure pro-
tection. The active signals are time monitored individually. An alarm is generated in
the event of an excess for more than 15 s.
• The monitoring time between triggering and release is set with the parameter T-BF
2chan (128/BU).
• If the protection picks up, the following alarm is generated: "TripBIErr $03"
(FNo. 177.1361.xx/CU), the group alarm "TripRelErr" (FNo. 10486/CU)
and the further processing of the binary input is blocked.
If there is no TRIP release, the following alarm is generated:
(FNo. 177.1362.xx/CU) "noTripRel $03".
5.9.8 Setting Notes
Tmin TRIP The parameter Tmin TRIP (6106/CU) is used to set the minimum time that must
elapse before the TRIP command is reset. This time is started with the output of a
TRIP command.
In general, a TRIP command is reset via the current flow control (see Chapter 5.9.1,
page 165). If non-energized feeders, e.g. radial feeders, are tripped without any feed-
back, a safe reset of the TRIP command to the circuit breaker trip coil can instead be
ensured with the parameter Tmin TRIP (6106/CU). The setting must be higher than
the maximum circuit breaker closing time.
Local
control of BU
The parameter CTRL REL BU (6318/CU) is used to release or block changes of the
bay unit parameter Bay status (XX12/CU) locally on the bay units. This applies only
to the feeder settings out of service and maintenance. It affects also the pos-
sibility to change the operating status by means of the function keys F1 and F3 on the
bay unit operator panel.
Note
The parameter T TRIP (1141/BU) can only be set with the bay unit running in
stand-alone mode. If the bay unit is connected with the central unit, the setting of
this parameter is overwritten by the central unit Tmin TRIP (6106/CU).
With the bay unit linked to the central unit, the setting of this parameter is transmitted
from the central unit to the bay units. The local setting in the bay units is overwritten.
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