Siemens 7UT51

4
Transformer Differential Protection (87T and 87HS)
7UT51 v3
42 PRIM-2330C
The relay performs a Fourier analysis of the differential
current using numerical filters optimized for transient
behavior. Hence, no additional restraining measures
are necessary.
Figure 4.4
Typical CT Wiring for a Two
-
Winding, Delta
-
Wye Transformer
7UT51 Relay
a
A
b
B
c
C
Primary
Secondary
I
A
I
B
I
C
I
a
I
b
I
c
3A1 3A2
2A1
2A2
1A1
1A2
3B1
3B2
2B1
2B2
1B1
1B2
Vector
Group 1