Siemens SIPROTEC 7SA522 Manual page 340

2 Functions
General Trip
Terminating the
Trip Signal
Figure 2-153 Storage and termination of the trip command
340
All trip signals for the protective functions are connected by OR and generate the
message ´5HOD\ 75,3µ. This can be allocated to LED or output relay.
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 2-153). At the same
time, the minimum trip command duration 70LQ 75,3 &0' is started. 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 commands
can only be terminated when the last protection function dropped out (i.e. functions no
longer pick up) AND the minimum trip signal duration expired.
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 (Subsection "Detection of the Circuit Breaker Position") and the flow of cur-
rent. The residual current  that is certainly undershot when the circuit breaker
pole is open is set in address 3ROH2SHQ&XUUHQW. Address  5HVHW 7ULS &0'
determines under which conditions a trip command is reset. If &XUUHQW2SHQ3ROH is
set, the trip command is reset as soon as the current disappears. It is important that
the value set in address  3ROH2SHQ&XUUHQW (see above) is undershot. If
&XUUHQW $1' &% 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 contacts is allocated via a binary input.
7SA522 Manual
C53000-G1176-C155-3