Application Guide - NP900 Series
80 (504
)
A996A
D
IRECTLY OR SMALL IMPEDANCE GROUNDED NETWORK
Figure 3.2.5.2-41 Angle tracking of DEF function. Petersen coil grounded network model.
In directly grounded network the amplitude of single phase fault current is similar to
amplitude of short circuit current. Directly or small impedance grounded network schemes
are normal in transmission, distribution and in industry.
Phase angle setting of the trip area is adjustable as is the base direction of the area
(angle offset).
U0
I
0
F2 current
I
0
F1 current
