Functions
2.16 Function Control
SIPROTEC, 7SD80, Manual
E50417-G1140-C474-A1, Release date 09.2011
195
2.16.2
Overall Tripping Logic of the Device
3-Pole Tripping
The device trips 3-pole in the event of a fault. The output function
„Relay TRIP“
is used for to send the
command to the circuit breaker.
General Trip
All trip signals for the protection functions are connected by OR and generate the indication
„Relay TRIP“
.
This indication can be routed to LED or output relays.
Terminating the Trip Signal
A trip command once transmitted is stored (see Figure 2-78). At the same time, the minimum trip command
duration
TMin TRIP CMD
is started. It ensures that the command is transmitted to the circuit breaker for a
sufficient amount of time, even if the tripping protection function drops out very quickly. The trip commands can
only be reset after all tripping protection functions have dropped out and after the minimum trip command time
has elapsed.
A further condition for terminating the trip command is that the circuit breaker is recognized to be open. The
function control of the device checks this condition by means of the circuit-breaker position feedback (Section
„Detection of the Circuit-Breaker Position“) and the flow of current. In address
1130
the residual current
PoleOpenCurrent
is set which is certainly undershot when the circuit-breaker pole is open. 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 falls below the setting
in address
1130
PoleOpenCurrent
(see above). If
Current AND 52a
is set, the circuit-breaker auxiliary
contact must also send a message that the circuit breaker is open. This setting requires the position of the aux-
iliary contact to be routed 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 2-78
Storage and termination of the trip command