Inrush-Current Detection/Blocking - Siemens SICAM Manual

Device Functions
4.1 Description
NOTE
i
i
The V threshold is not considered during I
NE

Inrush-Current Detection/Blocking

4.1.25
The device detects the presence of high level of 2nd harmonic current. For example, a transformer inrush
current. If the 2nd harmonic current is greater than 15 % of the measured phase current of any of the 3
phases, the device does not issue a fault indication for the set threshold I>, tI>, I
persists for more than the configured CrossBlockTimer value, then the device displays a fault indication. The
device does not block the fault indication if the fault current is above the set threshold I>> for the time tI>>.
If the fault current persists for the respective time setting (tI> for phases, tI
blocking function monitors the inrush current. The inrush current is detected by analyzing the magnitude of
the 2nd harmonic components of the phase vectors.
[lo_sfcm-inrushcrnt-dct, 2, en_US]
Figure 4-18
50
Inrush-Current Detection Logic Diagram
> pickup.
N
>, and tI >. If the fault
N N
> for ground), the inrush-current
N
SICAM, Feeder Condition Monitor, Manual
E50417-H8940-C580-A4, Edition 03.2019