Functions
2.3 Differential Protection
SIPROTEC, 7SD5, Manual
C53000-G1176-C169-5, Release date 02.2011
101
Pickup of the differential protection
Figure 2-31 shows the logic diagram of the differential protection. The phase-selective indications of the stage
are summarised to form general phase indications. In addition, the device indicates which stage picked up.
Figure 2-31
Pickup logic for the differential protection function
As soon as the differential protection function registers a fault within its tripping zone, the signal
„Diff. Gen.
Flt.“
(general device pickup of the differential protection) is issued. For the differential protection function
itself, this pickup signal is of no concern since the tripping conditions are available at the same time. This signal,
however, is necessary for the initiation of internal or external supplementary functions (e.g. fault recording, au-
tomatic reclosure).
