Differential Protection Pickup Logic And Tripping Logic; Functional Description - Siemens SIPROTEC 4 7SD80 Manual

Functions
2.2 Phase Comparison Protection and Ground Differential Protection

Differential Protection Pickup Logic and Tripping Logic

2.2.5
2.2.5.1

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
Tripping Logic
The following figure shows the tripping logic of the differential protection.
[lo-esd-erd-aus-20101117, 2, en_US]
Figure 2-16
If the pickup signals apply for longer than the configurable trip time delay, the differential protection trips.
62
General pickup
Differential protection trip
SIPROTEC 4, 7SD80, Manual
E50417-G1100-C474-A2, Edition 02.2018