Functions
2.11 Function Logic
SIPROTEC, 7RW80, Manual
C53000-G1140-C233-1, Release date 10.2010
113
2.11 Function Logic
The function logic coordinates the execution of protection and auxiliary functions, it processes the resulting de-
cisions and information received from the system. This includes in particular:
– Fault Detection / Pickup Logic
– Processing Tripping Logic
2.11.1 Pickup Logic of the Entire Device
General Device Pickup
The pickup signals for all protection functions in the device are connected via an OR logic and lead to the
general device pickup. 4 It is initiated by the first function to pick up and drop out when the last function drops
out. As a consequence, the following message is reported: 501 „Relay PICKUP“.
The general pickup is a prerequisite for a number of internal and external consequential functions. The follow-
ing are among the internal functions controlled by general device pickup:
• Start of a trip log: From general device pickup to general device dropout, all fault messages are entered in
the trip log.
• Initialization of Oscillographic Records: The storage and maintenance of oscillographic values can also be
made dependent on the general device pickup.
Exception:
Apart from the settings ON or OFF, some protection functions can also be set to Alarm Only. With
setting Alarm Only no trip command is given, no trip log is created, fault recording is not initiated and no spon-
taneous fault annunciations are shown on the display.
External functions may be controlled via an output contact. Examples are:
• Automatic reclosing devices,
• Starting of additional devices, or similar.
2.11.2 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 2-35). 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
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