32
TB MRD1-G 11.97 E
5.3.4
Protection parameters
Differential protection
The tripping characteristic of the
MRD1
can be set with four parameters:
Idiff0:
Error of the CTs
Idiff2:
Additional error of the CTs (linear range of the CTs)
Idiff10:
Additional error by saturation of the CTs
Idiff>>:
maximum permitted difference current
d[Id]:
raise up of characteristic curve by offset in case of characteristic harmonics
In:
Generator nominal current (or motor nominal current)
0
Stabilisierungsstrom
stabilizing current
Is / In
Differenzstrom
differential current
Id / In
5
Idiff
(Is/In=10)
10
Idiff >>
1
2
8
Einstellbereich der Kennlinie
setting range of characteristic
2
8
I
II
III
Idiff
(Is/In=2)
Idiff
(Is/In=0)
1
0,2
0,1
0,5
d[Id]
Fig: Possible setting range of the characteristic