Tripping Logic Of The Entire Device; Setting Notes - Siemens 7SK80 Manual

2.19.2

Tripping Logic of the Entire Device

General Tripping
The trip signals for all protective functions are connected by OR and generate the message 511 „Relay
TRIP".
This message can be configured to an LED or binary output, just as the individual tripping messages can.
Terminating the Trip Signal
Once the trip command is output by the protection function, it is recorded as message „Relay TRIP" (see
figure 2-98). At the same time, the minimum trip command duration TMin TRIP CMD 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 be terminated first when the last protection func-
tion has dropped out (no function is in pickup mode) AND the minimum trip signal duration has expired.
Finally, it is possible to latch the trip signal until it is manually reset (lockout function). This allows the circuit-
breaker to be locked against reclosing until the cause of the fault has been clarified and the lockout has been
manually reset. The reset takes place either by pressing the LED reset key or by activating an appropriately
allocated binary input („>Reset LED"). A precondition, of course, is that the circuit-breaker close coil – as
usual – remains blocked as long as the trip signal is present, and that the trip coil current is interrupted by the
auxiliary contact of the circuit breaker.
Figure 2-98
2.19.3

Setting Notes

Trip Signal Duration
The minimum trip command duration TMin TRIP CMD was described already in Section 2.1.3. This setting
applies to all protective functions that initiate tripping.
SIPROTEC, 7SK80, Manual
E50417-G1140-C344-A5, Release date 11.2012
Terminating the Trip Signal
Functions
2.19 Function Logic
259