Siemens SIPROTEC 4 7VK61 Manual page 156

Functions
2.8 Function Control and Circuit Breaker Test
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
CMD (address 240) is started. This ensures that the trip command is output to the circuit breaker for a suffi-
ciently 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
singlepole 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 current. In address 1130 PoleOpenCurrent, the residual current threshold which may definitely not
be exceeded 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
undershot. 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.
If the 7VK61 relay is operated without current transformer connection, the setting1135 Reset Trip CMD =
CurrentOpenPole termination of the trip command is only determined by the minimum trip time (TMin
TRIP CMD). If the setting is Reset Trip CMD = Current AND CB the trip command will be terminated by
the auxiliary contacts of the circuit breaker.
[logik-speich-absteuer-ausloese-wlk-020802, 1, en_GB]
Figure 2-68
Reclosure Interlocking
When a protection function has tripped the circuit breaker, it is often desired to prevent reclosing until the
tripping cause has been found. 7VK61 enables this via the integrated reclosure interlocking.
The interlocking state ("LOCKOUT") will be realized by an RS flipflop which is protected against auxiliary
voltage failure (Figure
156
Figure 2-68). At the same time, the minimum trip command duration TMin TRIP
Storage and termination of the trip command
2-69). The RS flipflop is set via binary input >Lockout SET (No. 385). With the output
SIPROTEC 4, 7VK61, Manual
C53000-G1176-C159-5, Edition 05.2018