Functions
2.25 Function Control and Circuit Breaker Test
SIPROTEC, 7SD5, Manual
C53000-G1176-C169-5, Release date 02.2011
454
General Trip
All trip signals for the functions are connected by OR and generate the message
„Relay TRIP“
. This can
be allocated to LED or output relay.
Terminating the Trip Signal
Once a trip command is initiated, it is phase segregatedly latched (in the event of three-pole tripping for each
of the three poles) (refer to Figure 2-224). At the same time, the minimum trip command duration
TMin TRIP
CMD
(address
240
) is started. This ensures that the trip command is output to the circuit breaker for a sufficiently
long time even if the tripping protection function resets very rapidly. The trip commands can only be reset after
all tripping protection functions have dropped out and after the minimum trip command duration has elapsed.
A further condition for the reset of the trip command is that the circuit breaker has opened, in the event of single-
pole tripping the relevant circuit breaker pole. In the function control of the device, this is checked by means of
the circuit breaker position feedback (Section „Detection of the Circuit Breaker Position“) and the flow of cur-
rent. In address
1130
PoleOpenCurrent
, the residual current threshold which may definitely not be exceed-
ed when the circuit breaker pole is open, is set. Address
1135
Reset Trip CMD
determines under which
conditions a trip command is reset. If
CurrentOpenPole
is set, the trip command is reset as soon as the
current disappears. It is important that the value set in address
1130
PoleOpenCurrent
(see above) is un-
dershot. If
Current AND CB
is set, the circuit breaker auxiliary contact must send a message that the circuit
breaker is open. It is a prerequisite for this setting that the position of the auxiliary contact is allocated via a
binary input. If this additional condition is not required for resetting the trip command (e.g. if test sockets are
used for protection testing), it can be switched off with the setting
Pickup Reset
.
Figure 2-224
Storage and termination of the trip command