Siemens 7SR11

7SR11 & 7SR12 Description Of Operation
©2012 Siemens Protection Devices Limited Chapter 1 Page 39 of 76
1
&
&
50SEF-n Dir En
67SEF Fwd
67SEF Rev
VT Fail
& &
&
1
V
0
I
4
(I
SEF
)
3I
0
cos(θ-θ
c
)
c
I
4
(I
SEF
)
&
50SEF-n Dir En
&
= 50SEF-n
= Delayed
AUTORECLOSE
3I
0
cos(θ-θ
c
)
Wattmetric Block
Wattmetric Block
Figure 1-36 Logic Diagram: 7SR12 SEF Instantaneous Element