Siemens SIPROTEC 4 7SD80, Manual

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Differential Protection Pickup Logic and Tripping Logic
Functional Description
Pickup Logic
Once the differential protection function has reliably registered a fault within its tripping zone, the signal
87(N)L Gen.Flt.
(general pickup of the differential protection) is generated. 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 required to initiate the internal or external supplementary functions, e.g. fault
recording, automatic reclosing.
[lo-diff-g-anr-20110304, 1, en_US]
Figure 2-15 General pickup
Tripping Logic
The following figure shows the tripping logic of the differential protection.
[lo-esd-erd-aus-20101117, 2, en_US]
Figure 2-16 Differential protection trip
If the pickup signals apply for longer than the configurable trip time delay, the differential protection trips.
2.2.5
2.2.5.1
Functions
2.2 Phase Comparison Protection and Ground Differential Protection
62 SIPROTEC 4, 7SD80, Manual
E50417-G1100-C474-A2, Edition 02.2018