Siemens SIPROTEC 7UT613 series Manual page 438

4 Technical Data
438
Figure 4-3 Restraining influence of n-th harmonic in transformer differential protection
I
differential current = |I
diff
I
Nominal current of protected object
NObj
I
Current at nominal frequency
fN
I
Current at n times the frequency (n = 3 or 4)
nf
Figure 4-4 Frequency influence in transformer differential protection
I
Differential current = |I
diff
I
Nominal current of the protected object
NObj
I
Current at any frequency within specified range
Xf
+ I
|
1 2
+ I
|
1 2
7UT613/63x Manual
C53000-G1176-C160-2