Technical Data
4.8 Differential Protection (ANSI 87T) for Transformers
SIPROTEC, 7UM62, Manual
C53000-G1176-C149-7, Release date 03.2010
480
Figure 4-10 Restraining Influence of Higher-Order Harmonics
Figure 4-11 Influence of Frequency in Transformer Differential Protection
where:
I
DIFF
Differential current = |I
1
+ I
2
|
I
fN
Current at nominal frequency
I
Xf
Current at any frequency within specified range