[loinru02-100611-01.tif, 2, en_US]
Figure 6-81
Basic Structure of the Inrush-Current Detection
Harmonic Analysis
For this method of measurement, the content of the 2nd harmonic and the fundamental component (1st
harmonic) are determined for each of the phase currents I
A
, I
B
, and I
C
and the quotient I
2nd harm
/ I
1st harm
is
formed from this. If this quotient exceeds the set threshold value, a phase-selective signal is issued.
If 95 % of the set threshold value is exceeded, this leads to a pickup reset (dropout ratio = 0.95).
Protection and Automation Functions
6.8 Inrush-Current Detection
SIPROTEC 5, Overcurrent Protection, Manual 487
C53000-G5040-C017-8, Edition 07.2017
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