REG 316*4 1MRB520049-Uen / Rev. F ABB Switzerland Ltd
3-109
0t
Tripping stage
Alarm stage
I
2
I
2
HEST 905 015 C
In cases where both stages are used for tripping, the one with
the higher setting must be faster.
Compensating the frequently differing rated currents of generator
and c.t’s is also recommended for the NPS protection. The
corresponding compensated setting is given by
Setting = calculated setting
I
I
GN
N1
Typical settings:
1st. stage (alarm)
I2-Setting 0.1 I
N
Delay 5 s
2nd. stage (tripping)
I2-Setting 0.15 I
N
Delay 10 s
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