2 Functions
204
7UM61 Manual
C53000-G1176-C127-3
2.34.2 Tripping Logic of Device
This section describes general pickup and terminating of the trip command.
2.34.2.1 Functional Description
General Trip
The trip signals for all protective functions are OR-combined and generate the
message
“Relay TRIP”
.
This annunciation, like individual trip indications, can be allocated to an LED or an
output relay. It can also be used as a group indication.
Terminating the
Trip Signal
For terminating the trip command the following applies:
• If a protective function is set to
Block. Relay
, it is blocked for the activation of
the output relay. The other protective functions are not affected by this.
• A trip command once transmitted is stored (see Figure 2-77). The minimum trip
command duration
T TRIPCOM MIN
is started at the same time. This ensures that
the command is transmitted to the circuit breaker for a sufficient amount of time,
even if the function which issued the trip signal drops out quickly. The trip com-
mands can only be terminated when the last protection function dropped out (i.e.
functions no longer pick up) AND the minimum trip signal duration has expired.
• Finally, it is possible to latch the trip signal until it is manually reset (lockout func-
tion). This allows interlocking the circuit breaker against reclosing until the cause of
the malfunction has been clarified and the interlock has been manually reset. The
reset takes place either by pressing the LED reset key or by activating an appropri-
ately masked binary input (
“>LED-Acknowledgement”
). A precondition of
course is that the circuit breaker trip coil – as usual – remains blocked as long as
the trip signal is present, and the trip coil current is interrupted by the auxiliary
contact of the circuit breaker.
Figure 2-77
Terminating the Trip Signal, Example of a Protective Function
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