Functions
2.17 Function Logic
SIPROTEC, 7SK80, Manual
E50417-G1140-C344-A4, Release date 08.2010
239
2.17 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
2.17.1 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.
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